Originally published 28 September 2018; corrected 13 December 2018
www.sciencemag.org/content/361/6409/eaao4227/suppl/DC1
Supplementary Materials for
Neutrophil extracellular traps produced during inflammation awaken
dormant cancer cells in mice
Jean Albrengues, Mario A. Shields, David Ng, Chun Gwon Park, Alexandra Ambrico,
Morgan E. Poindexter, Priya Upadhyay, Dale L. Uyeminami, Arnaud Pommier, Victoria
Küttner, Emilis Bružas, Laura Maiorino, Carmelita Bautista, Ellese M. Carmona, Phyllis
A. Gimotty, Douglas T. Fearon, Kenneth Chang, Scott K. Lyons, Kent E. Pinkerton,
Lloyd C. Trotman, Michael S. Goldberg, Johannes T.-H. Yeh, Mikala Egeblad*
*Corresponding author. Email: [email protected]
Published 28 September 2018, Science 361, eaao4227 (2018)
DOI: 10.1126/science.aao4227
This PDF file includes:
Materials and Methods
Figs. S1 to S15
Captions for Movies S1 to S8
References
Other Supplementary Material for this manuscript includes the following:
(available at www.sciencemag.org/content/361/6409/eaao4227/suppl/DC1)
Movies S1 to S8
Correction: In the Research Article “Neutrophil extracellular traps produced during
inflammation awaken dormant cancer cells in mice,” figure panels S6C, S6D, S7H, S8D,
and S8E have been replaced. A systematic error in the transfer of raw image files into
image analysis software and subsequently Adobe Illustrator led to errors in the assembly
of figure panels S6C, S6D, S7H, and S8E. In addition, due to human error, an incorrect
part of the gel was used for the condition “C5a” during assembly of fig. S8D. None of
these changes affect the conclusions of the paper.
2
Supplementary Text
Supplementary Materials and Methods
Cell culture
D2.0R and D2.A1 cells were obtained from Dr. Jeffrey Green (National Institutes of Health
[NIH]) and cultured in Dulbecco’s Modified Eagle Medium (DMEM) (#10-013-CV,
Cellgro) supplemented with 10% fetal calf serum (FCS) (#1500-500, Seradigm), 100
units/mL penicillin, and 100 g/mL streptomycin. MCF-7 cells (obtained from Cold Spring
Harbor Laboratory [CSHL] Tissue Culture Facility) were cultured in DMEM
supplemented with 10% FCS, 100 units/mL penicillin, 100 g/mL streptomycin, and 10
nM -estradiol (#E8875, Sigma). Plate-E and 293T cells (obtained from CSHL Tissue
Culture Facility) were cultured in DMEM supplemented with 10% FCS. Cells were tested
repeatedly for mycoplasma over the course of the study, and were never positive.
To generate mCherry- and luciferase-expressing cells, a pGIPz vector containing
cDNA for mCherry and luciferase (Open Biosystems) was used. Lentiviral supernatants
were collected from a 293T packaging cell line transfected with the construct. D2.0R and
MCF-7 cells were infected with the viral supernatants overnight in the presence of 10
μg/mL polybrene (#TR-1003-G, Sigma) and selected with 1 μg/ml puromycin (#sc-
108071, Santa Cruz Biotechnology).
The pBOB-EF1-FastFUCCI-Puro vector was used to express the FUCCI cell cycle
reporter (23). Lentiviral supernatants were collected from 293T packaging cells transfected
with the construct. D2.0R cells were infected with the viral supernatants through a 1.5-hour
spin infection at 1,000 x g at 33 °C, and 72 hours later, were selected with 2 μg/ml
puromycin (#sc-108071, Santa Cruz Biotechnology). Then, the cells were sorted for high-
expressing red and/or green cells.
The pTOL-hCMV-TET3G-Hygro Transactivator vector (CSHL Cancer Center
Functional Genomics and Genetics Shared Resource) was used to express the Tet-On® 3G
doxycycline-dependent transactivator. Lentiviral supernatants were collected from 293T
packaging cells transfected with the construct. D2.0R mCherry-luciferase cells were
infected with the viral supernatants overnight in the presence of 10 μg/mL polybrene and
selected with 750 μg/ml hygromycin B (#10687010, Thermo Fisher Scientific).
Short hairpins (Ultramir, 5th-generation (50)) targeting Integrin , FAK, MLCK, and
YAP, as well as control short hairpins were cloned into the LTR-TRE3Gpro-DsRed-
mir30cassette-PGKpro-Venus-IRES-Neo-sinLTR vector. Lentiviral supernatants were
collected from a 293T packaging cell line transfected with the constructs. D2.0R mCherry-
luciferase Tet-On 3G cells were infected with the viral supernatants overnight in the
presence of 10 μg/mL polybrene (Sigma) and selected with 750 μg/ml geneticin
(#10131035, Thermo Fisher Scientific). In vitro, 1 μg/ml doxycycline (#D9891, Sigma)
was used to induce shRNA expression. The shRNA sequences used to target Integrin ,
FAK, MLCK, and YAP, as well as control short hairpins are listed below.
Integrins 3, 5, 6, 7, 8, 9, v, NE and MMP9 knockdowns were performed by
infecting D2.0R cells with lentivirus using the MISSION shRNA Lentiviral Transduction
system from Sigma and the following RNAi Consortium numbers (TRCNs): 3 TRCN
0000065998 and TRCN 0000066000; 5 TRCN 00000262922 and TRCN 00000262923;
6 TRCN 0000066148 and TRCN 0000066149; 7 TRCN 0000066188 and TRCN
3
0000066192; 8 TRCN 0000066238 and TRCN 0000066240; 9 TRCN 0000066328 and
TRCN 0000066332; v TRCN 0000066590 and TRCN 0000066591; NE TRCN
0000032596 and TRCN 0000453732; MMP9 TRCN 0000031230 and TRCN 0000031233;
non-targeted shRNA control Lentiviral Transduction Particles SHC002V. Lentiviral
transduction was done following the manufacturer’s instructions. Infected cells were
selected with 1 μg/ml puromycin (#sc-108071, Santa Cruz). The shRNAs all had the same
sequence surrounding the 21 specific nucleotides (underlined), as exemplified for the
Renilla Luciferase non-targeting control:
AGATCTTGTTTGAATGAGGCTTCAGTACTTTACAGAATCGTTGCCTGCACATC
TTGGAAACACTTGCTGGGATTACTTCTTCAGGTTAACCCAACAGAAGGCTAA
AGAAGGTATATTGCTGTTGACAGTGAGCGCAGGAATTATAATGCTTATCTAT
AGTGAAGCCACAGATGTATAGATAAGCATTATAATTCCTATGCCTACTGCCTC
GGACTTCAAGGGGCTACTTTAGGAGCAATTATCTTGTTTACTAAAACTGAATA
CCTTGCTATCTCTTTGATACATTTTTACAAAGCTGAATTAAAATGGTATAAAT
TAAATCACTTTACGCGT
For the shRNA sequences presented below, only the 21 specific nucleotides are listed.
Integrin 1-1: ATAATGTGATCCAGCTAATCA
Integrin 1-2: ATCCCACTTCAATCTCACCAA
FAK-1: AGACCTGGCATCTTTGATATT
FAK-2: AACCTGGCATCTTTGATATTA
MLCK-1: ACACTGTCACCGTCCAAGAGA
MLCK-2 :CGACAATGATAACGAGACCTT
YAP-1: CGACATCTTCTGGTCAAAGAT
YAP-2: CGGCTGCCACCAAGCTAGATA
Cell culture reagents
Lipopolysaccharide (LPS) (#L4391, Sigma) was used at 100 ng/ml; phorbol 12-myristate
13-acetate (PMA, #P1585, Sigma) was used at 20 nM; N-formylmethionyl-leucyl-
phenylalanine (fMLP, #F3056, Sigma) was used at 1 μM; recombinant mouse and human
complement 5a (#2150-C5/CF and #2037-C5/CF, respectively, R & D Systems) was used
at 100 ng/ml; cigarette smoke extract (CSE, Murty Pharmaceuticals Inc., generated by
smoking on an Federal Trade Commission Smoke Machine, University of Kentucky’s
3R4F standard research cigarettes) was used at 600 μg/ml unless otherwise stated. The
PAD4 inhibitor GSK484 (#14788, Cayman Chemical) was used at 10 μM to inhibit
Neutrophil Extracellular Traps (NETs) formation, and 1.5 units/ml of DNase I
(#04536282001, Sigma) was used to digest NET scaffolds. Taurolidine (#T7329, Sigma)
was used at 50 μg/ml to neutralize LPS. Recombinant mouse and human neutrophil elastase
(NE) (#4517-SE-010, R & D Systems and #ab91099, Sigma, respectively) and
recombinant mouse and human metalloproteinase (MMP) 9 (#909-MM-010, R & D
Systems and #ab157344, Abcam, respectively) were used at 2 μg/ml unless otherwise
stated. Anti-Integrin 1 antibodies, clone AIIB2 (#MABT409, EMD Millipore) and clone
Ha2/5 (#5555003, BD Biosciences) were used at 10 μg/ml to inhibit Integrin 1 activity;
PF-562271 (#HY-10458, Medchem Express) was used at 1 μM to inhibit FAK activity;
PD184352 (#sc-202759, Santa Cruz Biotechnology) was used at 1 μM to inhibit MEK
4
activity; ML7 hydrochloride (#4310, Tocris) was used at 1 μM to inhibit MLCK activity;
blebbistatin (#S709901, Selchem Chemicals) was used at 5 μM to inhibit non-muscle
myosin II; and verteporfin (#SML0534, Sigma) was used at 1 μM to inhibit YAP activity.
Sivelestat (#3535, Tocris), MMP9 inhibitor 1 (#44278, Calbiochem), and Cathepsin G
inhibitor 1 (#219372, EMD Millipore) were used at 10 μM to inhibit NE, MMP9, and
Cathepsin G activity, respectively. mLaminin-111 (#3446-005-01, R & D Systems), hLN-
111, -121, -211, -221, -411, -421, -511 (Biolamina), mTSP-1 (#7859-TH-050, R & D
Systems), and hTSP-1 (#3074-TH, R & D Systems) were used as indicated below in the
methods section.
Antibodies
For Western blot analysis, antibodies against Integrin 1 (#sc-6622) and YAP (#sc10199)
were purchased from Santa Cruz Biotechnology; MLC2 (#3672), pThr18/Ser19-MLC2
(#3674), pT202/Y204-ERK1/2 (#9101), ERK1/2 (#9107S), HSP90 (#4877S), and FAK
(#3285) were from Cell Signaling; laminin-111 (#ab11575) and MLCK (#ab76092) were
from Abcam; TSP-1 (#MS-1066-P1ABX) was from Thermo Fisher Scientific, and pY397-
FAK (#NBP1-60837) was from Novus Biologicals. For immunofluorescence staining of
in vitro cultures, antibodies against Ki67 (#NB110-89717, Novus Biologicals), active
mouse Integrin 1 (clone 9EG7, #550531, BD Biosciences), active human Integrin 1
(Clone Huts-21, #556047, BD Pharmingen), myeloperoxidase (#A0398, Dako), and
Histone H2B (#ab52484, Abcam) were used. Alexa Fluor 568 phalloidin (#A12380,
Thermo Fisher Scientific) was used to stain F-actin. For immunofluorescence on tissue
samples, antibodies against Ly6G (clone 1A8, #551459, BD Pharmingen), RFP-mCherry
(#600-401-379, Rockland or #M11217, Invitrogen), Ki67 (#12075, Cell Signaling),
myeloperoxidase (#AF3667, R & D Systems), laminin-111 (#ab11575, Abcam), and
citrullinated histone H3 (#ab5103, Abcam) were used. For ELISA, an anti-elastase
antibody (#sc-9521, Santa Cruz Biotechnology) and an anti-DNA peroxidase conjugated
antibody (#11774425001, Roche) were used. For flow cytometry analysis, antibodies
against Integrin 1 (#142605), Integrin 2 (#103515), Integrin 4 (#103705), Integrin 5
(#103805), Integrin v (#104105), CD4 (#100428, clone GK1.5), CD8 (#100714, clone
53.6.7), TcR beta clone (#109222, clone H57-597), TcR gamma delta (#118106, clone
GL3), CD19 (#152406, clone 1D3), CD45 (#103138, clone 30-F11), NKp46 (#137716,
clone 29A1.4), CD11b (#101224, clone M1/70), CD11c (#117318, clone N418), Ly6C
(#128016, clone HK1.4), Ly6G (#127606, clone 1A8), GR1 (#108408, clone RB6-8C5),
and streptavidin (#405214) were purchased from Biolegend; Integrin 3 (#FAB2787P),
Integrin 6 (#FAB13501P), Integrin 7 (#FAB3518A), Integrin 8 (#AF4076), and
Integrin 9 (#FAB3827P) from R & D Systems; Integrin 10 (#PAC096Mu01) from
Cloud-Clone Corp.; and Integrin 1 (#037132) from US Biological Life Sciences.
Proliferation assay on LN-111 and TSP-1 coated hydrogel
In this assay, D2.0R cells were used on mLN-111- and mTSP-1-coated hydrogel, and
MCF-7 cells were used on hLN-111,-121, -211, -221, -411, -421, -511, and hTSP-1-coated
hydrogel. 96-well 0.2 kPa hydrogel plates (#SW96G-EC-0.2, Matrigen) were coated
overnight with 50 μg/ml hLN (Biolamina), 50 μg/ml mLN-111 (#3446-005-01, R & D
Systems), mTSP-1 (#7859-TH-050, R & D Systems) or hTSP-1 (#3074-TH, R & D
Systems). The next day, the coating solution was aspirated, and mCherry-luciferase MCF-
5
7 cells or D2.0R cells (2×103) were resuspended in 100 l of DMEM supplemented with
1% FCS and 10 μg/ml human or murine LN-111 and TSP-1, respectively, and added to the
coated plates. The following day, the medium was replaced with 100 μL of CM from
neutrophils cultured at indicated conditions. The CM was changed every four days.
Proliferation was measured by BLI after 14 days using a plate reader (SpectraMax i3,
Molecular Devices).
Extracellular matrix remodeling assay
In this assay, D2.0R cells were used on matrigel-coated culture plates or mLN-111- and
mTSP-1-coated hydrogel, and MCF-7 cells were used on hLN-111- and hTSP-1-coated
hydrogel. Murine recombinant proteases were used with D2.0R cells, while human
recombinant proteases were used with MCF-7 cells. Coated matrigel, laminin-111, or TSP-
1 was incubated with recombinant proteases or CM (with or without inhibitors, as indicated
in figure legends) overnight at 37 °C and washed twice with phosphate buffer saline (PBS)
before adding cancer cells to the culture. After 14 days, the number of cancer cells was
assessed by BLI as described above.
Isolation of neutrophils
Mouse neutrophils were harvested from eight-week-old female BALB/c mice. For
neutrophil isolation from NE KO and MMP9 KO mice, wild-type C57BL/6J mice from
Charles River Laboratories were used as controls; all the mice were eight-week old
females. The bone marrow of the femurs and tibias was isolated in sterile Hank’s buffered
salt solution (HBSS) without Ca2+/Mg2+ (#14175-095, Gibco) and containing
penicillin/streptomycin. The bone marrow cell pellets were resuspended in ammonium-
chloride-potassium (ACK) buffer (0.15 M NH4Cl, 10 mM KHCO3, 0.1 mM Na2-
ethylenediaminetetraacetic acid [EDTA] pH 7.4) and washed twice with HBSS without
Ca2+/Mg2+. Neutrophils were separated from mononuclear cells by layering 2 mL of the
cell suspension on 3 mL of 81% Percoll (#17-0891-02, GE Healthcare) and under 3 mL of
62% Percoll, followed by centrifugation at 2,500 x g for 20 min at 4 °C. The middle layer
enriched for neutrophils was washed twice in HBSS without Ca2+/Mg2+, and cells were
resuspended in serum-free DMEM.
Neutrophils were isolated from healthy female volunteers after approval by the IRB of
CSHL and after informed consent was obtained (IRB-13-025). Whole blood (10 mL) was
collected by venipuncture into a 15 mL centrifuge tube containing 2 mL of 0.5 M EDTA,
pH 8.0. Then, 5 mL of whole blood was layered on top of 5 mL of Polymorphprep
(#1114683, Axis-Shield) in a 15 mL tube and centrifuged at 500 x g for 30 min at room
temperature. The lower leukocyte band containing neutrophils was collected, washed, and
resuspended into 5 mL of ACK lysis buffer, washed twice in HBSS without Ca2+/Mg2+,
and finally resuspended in serum-free DMEM.
Western blot
For immunoblotting analysis, cells grown on matrigel or matrigel-coated 0.2 kPa hydrogel
were lysed on ice in lysis buffer (25 mM Tris [pH 6.8], 2% sodium dodecyl sulfate (SDS),
5% glycerol, 1% β-mercaptoethanol, 0.01% bromophenol blue) and the samples were
sonicated. Equal amounts of protein from each sample were loaded on SDS-
polyacrylamide gel electrophoresis, separated, and transferred onto nitrocellulose. The
6
immunoblots were incubated in blocking buffer (5% BSA, 10 mM Tris-HCl [pH 7.5], 500
mM NaCl) for 30 min at room temperature and probed with specific antibodies overnight
at 4 °C. Then, the immunoblots were washed three times for 10 min in Tris-buffered saline
Tween 20 (TBST, 10 mM Tris-HCl [pH 7.5], 500 mM NaCl, 0.1% Tween 20), incubated
with secondary antibodies for one hour at room temperature in blocking buffer, and washed
three times in TBST again. Immunodetection was performed using chemiluminescent
horseradish peroxidase (HRP) substrate (#RPN 2109, GE Healthcare).
Tissue lysate from lungs was isolated by washing the lung tissues once with cold PBS,
cutting them into smaller pieces, and homogenizing thoroughly in
radioimmunoprecipitation assay (RIPA) buffer (50 mM Tris HCl [pH 7.4], 1% NP-40,
0.5% sodium deoxycholate, 0.1% SDS, 150 mM NaCl, 50 mM NaF, and 2 mM EDTA)
with protease inhibitors (#11836145001, Roche). For 10 mg tissue, 500 μl of RIPA buffer
was used. After 30 min on ice, the samples were centrifuged at 10,000 x g for 20 min at 4
°C, and protein concentration was determined on the supernatant using a bicinchoninic acid
(BCA) protein assay (#23225, Thermo Fisher Scientific). Proteins (40 μg) were loaded on
SDS-polyacrylamide gel electrophoresis and processed as described above.
Immunofluorescence of cell cultures
Cells grown on 0.2 kPa hydrogel bound to a glass bottom for 14 days were fixed with 4%
PFA for 20 min at room temperature, rinsed twice in PBS, incubated in 50 mM of NH4Cl
for 10 min, and permeabilized with 0.5% Triton X-100 for 5 min. Cells were then incubated
in blocking buffer (PBS containing 1% BSA) for 30 min and incubated with antibodies
against active Integrin 1 (1:50) or Ki67 (1:100) in blocking buffer overnight at 4 °C. After
two washes in PBS, cells were incubated in the presence of phalloidin and fluorochrome-
conjugated secondary antibodies (1:250, Invitrogen) for 40 min, rinsed twice in PBS,
stained with DAPI for 5 min, rinsed in water, and placed in PBS for subsequent analysis.
Immunostaining of tissues samples
For paraffin-embedded tissue, the lungs were fixed overnight at 4 °C in 4% PFA,
transferred into PBS, processed using conventional methods, embedded in paraffin, and
sectioned at 8 μm. For optimal cutting temperature (OCT) compound-embedded tissue, the
lungs were fixed in 4% PFA overnight at 4 °C, transferred to 20% sucrose in PBS for 48
hours, frozen in OCT compound in a -80 °C freezer, and sectioned at 10 μm.
Paraffin-embedded tissue sections were deparaffinized and rehydrated, and antigen
retrieval was performed in EDTA buffer (10 mM Tris Base, 1 mM EDTA solution, 0.05%
Tween 20, pH 9.0). Sections were blocked with Fc Receptor blocker (#NB309, Innovex),
and incubated with 1 x blocking buffer (5% donkey serum [# D9663, Sigma], 2.5% BSA,
0.1% Triton X-100 in PBS). Then, sections were incubated with anti-myeloperoxidase
(1:100) and anti-citrullinated histone H3 antibodies (1:250) in 0.5 x blocking buffer
overnight at 4 °C. After three washes with PBS, the sections were incubated with
fluorochrome-conjugated secondary antibodies (1:150, Invitrogen) in 0.5 x blocking buffer
for 45 min in the dark at room temperature. After two washes with PBS and one with water,
sections were counterstained with DAPI and rinsed in water, and the slides were mounted
onto coverslips using mounting media (#17985-16, Electron Microscopy Sciences).
OCT compound-embedded tissue sections were post-fixed with ice-cold methanol and
acetone (1:1 ratio), rinsed with PBS, blocked with Fc receptor blocker (#NB309, Innovex)
7
and incubated with 1 x blocking buffer (5% donkey [#D9663, Sigma] or goat serum
[#X0907, Dako], 2.5% BSA, 0.1% Triton X-100 in PBS). Sections were then incubated
with either anti-RFP-mCherry (1:150); anti-Ki67 (1:100); anti-laminin-111 (1:100); anti-
laminin Ab19, Ab25, or Ab28 (10 ug/ml); anti-myeloperoxidase (1:100); anti-citrullinated
histone H3 antibodies (1:250); or anti-Ly6G (1:600) antibodies in 0.5 x blocking buffer
overnight at 4 °C. No staining was needed to detect the Fluorescence Ubiquitination Cell
Cycle Indicator (FUCCI)-expressing D2.0R cells on OCT compound-embedded tissue
sections. After three washes with PBS, the sections were incubated with fluorochrome-
conjugated secondary antibodies (1:250, Invitrogen) in 0.5 x blocking buffer for 45 min in
the dark at room temperature. After two washes with PBS and one with water, sections
were counterstained with DAPI and rinsed in water, and the slides mounted onto cover
slips using mounting media (#17985-16, Electron Microscopy Sciences).
Spontaneous metastasis assay with primary tumor removal
To test the effect of LPS-induced inflammation on dormant cells that had spontaneously
disseminated, mCherry-luciferase expressing MCF-7 cells (5 million per mouse) were
injected into the number 4 mammary fat pad of eight-week-old female nude mice in 50 μl
of PBS. These mice had been implanted with 17β-estradiol 0.36 mg/pellet (#SE-121,
Innovative Research of America) 72 h before MCF-7 cell injection. Tumors resulting from
orthotopic injection were resected after six weeks. The mice were re-implanted with new
17β-estradiol 0.36 mg/pellet five days after resection, and two days later, the mice were
treated with LPS and GSK484 as described above to assess the effect of experimental
inflammation on spontaneously disseminated, dormant cells.
Effects of tobacco smoke exposure on lung inflammation
To determine how tobacco smoke exposure affects neutrophil recruitment and laminin-111
remodeling in the lungs, eight-week-old female BALB/c were exposed to tobacco smoke
(TS) or filtered air for three weeks using a smoke exposure system (Dr. Kent Pinkerton
Laboratory, University of California, Davis). For the TS groups, mice were exposed five
days/week to an average concentration of 75 + 11 mg/m3 of tobacco smoke for 6 h/day
using 3R4F research cigarettes (Tobacco Research Institute, University of Kentucky),
which were burned at a rate of four cigarettes every 10 min, with a puff volume of 35 mL
over a duration of 2 s, once per minute. Both side-stream and mainstream cigarette smoke
was collected via a chimney and passed to a dilution and aging chamber to allow the
animals to acclimate to TS exposure. The TS exposure started at an initial concentration of
60 mg/m3 and was increased, ultimately achieving a final target concentration of 90 mg/m3.
After each six-hour exposure to TS, the mice were then kept in the same chamber but in
filtered air. For the control group, the mice were handled in the same way, but were exposed
to filtered air only for 24 h a day, 7 days/week for the duration of the study.
Effects of experimental inflammation on RapidCaP mice lung metastasis
The effect of LPS-induced lung inflammation was tested on the RapidCaP mouse model
with low spontaneous incidence of lung metastasis. LPS (50 μL at a concentration of 0.25
mg/ml or PBS as control) was administered intranasally on days 0, 3, and 6 with a P200
pipette into mice under anesthesia (2.5% isoflurane) that had developed prostate cancer but
had no metastasis detectable by BLI. The inhibitor GSK484 (PAD4 inhibitor, #17488,
8
Cayman Chemical) was used at 20 mg/kg (in 10% DMSO in PBS) to inhibit the formation
of NETs. The inhibitor was intraperitoneally injected, starting on the first day of LPS
treatment. On days when the mice received LPS administration, they were treated three
times with inhibitors (30 min before LPS administration, three hours after administration,
and six hours after administration). On all other days, one daily treatment was given,
continuing until the end of the experiment. To follow metastatic disease, mice were injected
intraperitoneally with luciferin (5 mg per mouse, #Luck-100, Goldbio) and imaged using
the IVIS Spectrum in vivo imaging system (#128201, PerkinElmer) every three days. If
the first round of LPS instillation did not result in lung metastasis as detected by BLI, a
second round of LPS instillation (43 days after the end of the first round and following the
same protocol) was performed on the remaining animals, which were all at a more
advanced disease stage but had remained free of lung metastases. Mice were followed for
up to 110 days and differences in lung metastasis among the three treatment groups (saline;
LPS + vehicle; LPS + PAD4 inhibitor) were analyzed by Kaplan-Meier lung metastasis-
free curves. The presence of lung metastasis was confirmed post-mortem using a
fluorescent microscope, as cancer cells also expressed tdTomato. If lung metastasis was
not detected post-mortem by whole lung fluorescence, the animal was considered
metastasis-free. As whole lung fluorescence analysis is not sensitive enough to detect
single isolated, or small clusters of cancer cells, the presence of cancer cells in the lungs
was also evaluated by immunofluorescence as described above.
Quantification of metastatic burden and metastatic foci
The metastatic burden was evaluated from lung sections stained with hematoxylin and
eosin, calculated as percentage of lung area. The number of metastatic foci normalized to
the evaluated lung area was also calculated from the same hematoxylin and eosin-stained
lung sections.
Quantification of neutrophils per field and percentage of NET-forming neutrophils
Neutrophils were counted as myeloperoxidase or Ly6G positive cells from at least three
representative immunofluorescence images (from 2 neighboring sections) from three
different mice. NET-forming neutrophils were counted as MPO and extracellular
citrullinated H3 positive cells from at least three representative immunofluorescence
images (from 2 neighboring sections) from three different mice. The percentage of NET-
forming neutrophils was calculated using the formula: (number of NET-forming
neutrophils/number of neutrophils)*100.
qRT-PCR analysis
RNA was prepared from total cell lysates or lung tissues using an RNeasy mini kit (#79254,
Qiagen) according to the manufacturer’s instructions. cDNA was synthesized using 500 ng
of cytoplasmic RNA using a RevertAid First Strand cDNA synthesis kit (#K1622, Thermo
Fisher Scientific), following the manufacturer’s instructions. Real-time PCR was
performed using Taqman gene expression master mix (#4369016, Applied Biosystems),
and the following primers from Applied Biosystems were used: Tbp (Mm 01277042), NE
(Mm 00469310), MMP9 (Mm 00442991), lama1 (Mm 01226102), lama2 (Mm 00550083),
lama3 (Mm 01254735), lama4 (Mm 01193660), lama5 (Mm 01222029), lamb1 (Mm
9
00801853), lamb2 (Mm 00493080), lamb3 (Mm 00493108), lamc1 (Mm 00711820),
lamc2 (Mm 00500494), and lamc3 (Mm 01324510).
The PCR reactions were performed on the StepOne Real-Time PCR system and
analyzed using the StepOneSoftware v2.1 (Applied Biosystems). Gene expression was
normalized to endogenous TBP expression, or relative expression of the respective gene
was determined after normalization to TBP and calculated with the following formula:
relative expression level = 2ddCT.
RNA in situ hybridization
RNA in situ hybridization was performed using the RNAscope 2.5 HD Reagent Kit-RED
(#322350, Advanced Cell Diagnostics), following the manufacturer’s instructions. The
following probes from Advanced Cell Diagnostics were used: lama1 (#494931), lamb1
(#517641), lamc1 (#517451), and positive control DapB (#310043).
NE and MMP activity assays
NE and MMP activities were measured in neutrophil CM. For NE activity, Neutrophil
Elastase 680 FAST Fluorescent Imaging Agent (0.5 μM, #NEV11169, PerkinElmer) was
incubated with neutrophil CM for 30 min in the dark, and the resultant fluorescence was
read at excitation/emission wavelengths of 663/690 nm using a plate reader (SpectraMax
i3, Molecular Devices). For MMP activity, Mca-PLGL-Dpa-AR-NH2 Fluorogenic MMP
Substrate (10 μM, #ES001, R & D Systems) was incubated with neutrophil CM for 30 min
in the dark, and fluorescence read at excitation/emission wavelengths of 320/405 nm using
a plate reader (SpectraMax i3, Molecular Devices).
To quantify the concentrations of active NE and MMPs in the samples, a standard curve
was generated using rNE or rMMP9 in DMEM. After subtracting background fluorescence
(from the soluble fluorescent substrate in medium without enzyme), the concentration was
calculated using the correlation coefficient of the standard curve. For protease activity from
lung samples, proteins were extracted in RIPA buffer on ice without protease inhibitors,
and 40 μg of protein was used with the fluorescent probes as described above.
Gelatin zymography
Conditioned medium from neutrophils (250,000, in 24-well plates containing 500 μl
serum-free DMEM), grown on plastic overnight, was mixed at a 1:1 ratio with loading
buffer (0.25 M Tris, pH 6.8, 2% SDS, 4% sucrose, bromophenol blue). Samples were
then loaded on 10% SDS-PAGE gels containing 1 mg/ml gelatin (#G1890, Sigma).
Following electrophoresis, the gels were rinsed twice in water and incubated in 2.5%
Triton X-100 for 90 min at room temperature. The gels were then washed twice in
substrate buffer (50 mM Tris pH 7.4, 200 mM NaCl, 2 mM CaCl2, 1 mM MgCl2) and
incubated in substrate buffer at 37 °C for 16 h. Gels were stained with 0.5% Coomassie
Blue R-250 (#F789-03, J.T. Baker; diluted in 10% ethanol and 10% acetic acid) and
destained in 10% ethanol and 10% acetic acid. Enzymatic activities appear as clear
bands in a blue background. For gelatin zymography from lung samples, proteins were
extracted in RIPA buffer on ice without protease inhibitors, and 40 μg of protein was mixed
at a 1:1 ratio with loading buffer before processing as described above.
Plasma sample collection from mice
10
Plasma samples were obtained from cardiac blood collection using a syringe with a 25 G
needle containing 25 μl of sodium citrate solution (#C3821, Sigma). Whole blood was
centrifuged at 4 °C at 1300 x g for 10 min, and the top plasma layer was collected.
Double-stranded (Ds) DNA quantification
DsDNA was quantified in plasma samples and CM using the Quant-iT PicoGreen dsDNA
assay kit (#P11496, Thermo Fisher Scientific), following the manufacturer’s instructions.
NET-ECM adhesion assay
96-well plates were coated with 50 g/ml of ECM protein for one hour at 37 °C. After two
washes in PBS, CM from neutrophils stimulated as indicated in the figure legends were
incubated on top of the coated wells for one hour at 37 °C. After two gentle washes with
PBS, dsDNA bound to the ECM proteins was quantified in the wells following the
manufacturer’s instructions (#P11496, Thermo Fisher Scientific).
NET-remodeled laminin-111 ELISA
To obtain monoclonal antibodies, hybridoma supernatants from individual hybridoma
colonies were screened by ELISA for the ability to recognize NET-remodeled laminin-
111. Positive hybridoma colonies were then isolated and seeded to establish pure
hybridoma clones from single cell colonies. Monoclonal antibodies (mAbs) were purified
from individual hybridoma clone culture supernatants. For ELISA, laminin-111, cleaved
laminin-111, or control proteins were coated (50 ng/well) on ELISA plates (#464718,
Thermo Fisher Scientific) following the manufacturer’s instructions. Prior to adding the
mAbs, the coated plate was blocked with PBS/0.5% BSA at 4 °C for six hours. After
blocking, mAbs (in PBS/0.5% BSA) were added to the ELISA plate and incubated at room
temperature for one hour, followed by three extensive washes with PBS/0.05% Tween 20.
The secondary antibody (#112-035-003, Jackson ImmunoResearch for anti-rat IgG HRP;
#115-035-003, Jackson ImmunoResearch for anti-mouse IgG HRP) was then added and
incubated at room temperature for 30 min, followed by three extensive washes with
PBS/0.05% Tween 20. Chromogenic binding signal was developed by using 3,3’,5,5’-
Tetramethylbenzidine ultra as the HRP substrate (#34028 Thermo Fisher Scientific),
following the manufacturer’s instructions. Data were collected by measuring the
absorbance at 450 nm with a plate reader (SpectraMax i3, Molecular Devices).
Treatment of mice with chimeric antibodies (chiAbs)
Mice injected with cancer cells at day 0 were treated with LPS on days 7, 10, and 13, as
described above. chiAbs (chiAb2, chiAb25, and chiAb28) were administered intravenously
at a dose of 200 μg/mouse to target laminin-111 in the lungs. chiAbs were given one day
before the first LPS administration, and then the treatment continued three times weekly
until the end of the experiment on day 33. Mouse IgG2A isotype was used as a control
(Clone C1.18.4, #BE0085, Bio X Cell, 200 μg/mouse). Although treatment with chiAb25
had a strong inhibitory effect on awakening, all mice treated with this antibody died
between days 22 and 25. Since Ab25, but not Ab28, binds full-length laminin, and since
no mice died when treated with chiAb28, DNase I, or PAD4/NE/MMP9 inhibitors, we
suspect that chiAb25 is toxic due to interference with normal laminin function.
11
Flow cytometry analysis
D2.0R cells (300,000) harvested in PBS containing 10 mM of EDTA were distributed in
96-well round-bottom plates and centrifuged at 2000 rpm for 1 min at 4 °C. The supernatant
was removed, and the cells were incubated in ice-cold Fluorescence Activated Cell Sorter
(FACS) buffer (1% FCS and 0.02% sodium azide in PBS) with Fc Block (#553142, BD
Biosciences, diluted 1:25) at 4 °C for 15 min. After one wash in FACS buffer, the cells
were incubated with antibody against integrin (1:100) for 30 min at 4 °C in the dark. If
unconjugated antibodies were used, the cells were washed once in FACS buffer and
incubated with fluorochrome-conjugated secondary antibodies (1:250, Invitrogen) for 30
min at 4 °C in the dark. The cells were then washed twice in FACS buffer and resuspended
in 450 μl of FACS buffer before analysis using a BD LSRFortessa instrument (BD
Biosciences) operated by FACSDIVA (BD Biosciences) software.
Plasma LPS quantification
Plasma endotoxin levels were measured using the Pierce LAL Chromogenic Endotoxin
Quantitation Kit (#88282, Thermo Fisher Scientific), following the manufacturer’s
instructions.
12
13
Fig. S1. Sustained lung inflammation promotes dormant cancer cell awakening.
(A) Quantification of the number of single, disseminated tumor cells (DTCs, murine
D2.0R) per lung area from untreated mice at days 7, 28 and 240 after injection (B) Mice
with D2.0R cells were monitored by bioluminescence imaging (BLI) over 8 months. (C)
LPS-induced sustained inflammation triggered awakening of murine breast cancer cells.
D2.0R cells expressing luciferase and mCherry were injected intravenously into syngeneic
BALB/c mice at day 0 and inflammation was induced through intranasal instillation of LPS
on days 7, 10, and 13. Mice were monitored by BLI every three days until metastatic burden
necessitated their euthanasia (n=5 mice per group; mean±SD). (D) Representative
micrographs of D2.0R cells (red), Ki67 (green), and DAPI (blue) stained lung sections at
day 28 from mice treated as indicated. Scale bars: 50 μm. (E) Mice with D2.0R cells were
treated as indicated, and metastatic burden in the lungs was quantified from hematoxylin
and eosin stained sections (n=5 mice per group; mean±SD). (F) LPS-induced sustained
inflammation triggered awakening of human breast cancer cells. MCF-7 cells expressing
luciferase and mCherry were injected intravenously into nude mice at day 0 and
inflammation was induced through intranasal instillation of LPS on days 7, 10, and 13.
Mice were monitored by BLI every three days until metastatic burden necessitated their
euthanasia (n=5 mice per group; mean±SD). (G) Representative micrographs of MCF-7
cells (red), Ki67 (green), and DAPI (blue) stained lung sections at day 33 from mice treated
as indicated. Scale bars: 50 μm. (H) Mice with MCF-7 cells were treated as indicated, and
metastatic burden in the lungs was quantified from hematoxylin and eosin staining (n=5
mice per group; mean±SD). (I, L) D2.0R murine breast cancer cells (I) or MCF-7 human
breast cancer cells (L) expressing luciferase and mCherry were injected intravenously into
syngeneic BALB/c mice or nude mice, respectively, at day 0, and inflammation was
induced through intranasal instillation of LPS on days 30, 33, and 36. Mice were monitored
by BLI every three days until metastatic burden necessitated their euthanasia (n=5 mice
per group; mean±SD). (J, M) Representative images of BLI at day 63. (K, N) Mice with
D2.0R (K) or MCF-7 (N) cells were treated as indicated, and metastatic burden in the lungs
was quantified from hematoxylin and eosin stained sections (n=5 mice per group;
mean±SD).
14
15
Fig. S2. Sustained lung inflammation promotes neutrophil recruitment and cell
cycle entry of dormant D2.0R cells.
(A) Experimental design used to test the effect of lung inflammation on neutrophil
recruitment. (B) Nasal LPS instillation induced neutrophil recruitment to lungs.
Immunostaining of lungs for Ly6G (red) with DAPI (blue) was used to assess the presence
of neutrophils in the lungs. Scale bar: 50 μm. (C) Quantification of neutrophils per field of
view from panel B (n=3 mice; mean±SD). (D) Visual representation of the FUCCI cell
cycle reporter. (E) Quantification of D2.0R cells in G0/G1 (black bar) or S/G2/M (red bar),
and clusters of cells (blue bar) in the lungs of mice treated as indicated (n=3 mice;
mean±SD; p<0.0001, Fisher’s exact test). (F) Representative micrographs of sections of
lungs with D2.0R cells expressing the FUCCI reporter (red, yellow and green)
counterstained with DAPI (blue), treated as indicated. Scale bars: 50 μm.
16
17
Fig. S3. Sustained lung inflammation promotes dormant cancer cell awakening
through neutrophil recruitment and correlates with the formation of NETs in the
lungs.
(A, B) Depletion of neutrophils using anti-Ly6G antibody. (A) Representative
immunostaining of lungs for myeloperoxidase (MPO, red) with DAPI (blue) after treating
mice treated with anti-Ly6G antibodies. MPO staining was used to detect neutrophils
because anti-Ly6G antibodies had been used to deplete neutrophils. Scale bar: 50 μm. (B)
Quantification of neutrophils per field of view (n=3 mice; mean±SD). (C) Experimental
design used to assess the effect of neutrophil depletion on LPS-induced inflammation.
(D-F) LPS-induced inflammation triggers neutrophil-dependent awakening. (D) Mice with
D2.0R cells were treated as indicated and monitored by bioluminescence imaging (BLI)
(n=5 mice per group; mean±SD). (E) Representative images of BLI signal on day 33. (F)
LPS-induced inflammation induced neutrophil-dependent awakening of D2.0R cells. Mice
with D2.0R cells were treated as indicated, and metastatic burden in the lungs was
quantified from hematoxylin and eosin stained sections (n=5 mice per group; mean±SD).
(G-I) LPS-induced inflammation drove neutrophil-dependent awakening of MCF-7 cells.
(G) Mice injected intravenously with MCF-7 cells and treated as indicated were monitored
by BLI every three days (n=5 mice per group; mean±SD). (H) Representative micrographs
of MCF-7 cells (red) in Ki67 (green) and DAPI (blue)-stained lung sections at day 33.
Scale bars: 50 μm. (I) Mice with MCF-7 cells were treated as indicated, and metastatic
burden in the lungs was quantified from hematoxylin and eosin stained sections (n=5 mice
for vehicle and LPS + Ly6G Ab groups, n= 3 mice for LPS + IgG group as two animals
had died from metastatic disease by this time point; mean±SD). (J-M) Nasal LPS
instillation induced NETs in the lungs. (J) Immunostaining of lungs for MPO (red) and
citrullinated histone H3 (green) with DAPI (blue) was used to assess the formation of NETs
in the lungs of mice treated as indicated. Scale bar: 50 μm. (K) Quantification of NET-
forming neutrophils in the lungs of mice treated as indicated (n=3 mice; mean±SD). (L)
ELISA quantification of NETs in the plasma of mice treated as indicated (n=3 mice per
group; mean±SD). (M) dsDNA was quantified in the plasma of mice treated as indicated
(n=3 mice per group; mean±SD).
18
19
Fig. S4. NETs promote awakening of dormant cancer cells after sustained lung
inflammation.
(A-C) NETs could be targeted with a PAD4 inhibitor or DNase I. (A) Quantification of
NET-forming neutrophils in the lungs of mice treated as indicated (n=3 mice; mean±SD).
(B) ELISA quantification of NETs in the plasma of mice treated as indicated (n=3 mice
per group; mean±SD). (C) dsDNA was quantified in the plasma of mice treated as indicated
(n=3 mice per group; mean±SD). (D) NETs could be targeted with DNase I-coated
nanoparticles (nanoDNase I). Immunostaining of lungs for MPO (red) and citrullinated
histone H3 (green) with DAPI (blue) was used to assess the formation of NETs in the lungs
of mice treated as indicated. Scale bar: 50 μm. (E) Quantification of NET-forming
neutrophils in the lungs of mice treated as indicated (n=3 mice; mean±SD). (F) ELISA
quantification of NETs in the plasma of mice treated as indicated (n=3 mice per group;
mean±SD). (G) Mice previously injected with D2.0R cells were treated as indicated, and
metastatic burden in the lungs was quantified from hematoxylin and eosin stained sections
(n=10 mice for vehicle and LPS groups; n=5 mice for DNase I and PAD4 inhibitor groups).
(H, I) DNase I-coated nanoparticles inhibit NET-mediated awakening of D2.0R cells. (H)
Mice were monitored by BLI (n=5 mice per group; mean±SD). (I) Mice with D2.0R cells
were treated as indicated, and metastatic burden in the lungs was quantified from
hematoxylin and eosin stained sections (n=5 mice per group; mean±SD). (J, K) LPS-
induced inflammation awakened MCF-7 cells in a NET-dependent manner. (J) Mice
previously injected with MCF-7 cells were treated as indicated and monitored by BLI (n=5
mice per group; mean±SD). (K) Mice with MCF-7 cells were treated as indicated, and
metastatic burden in the lungs was quantified from hematoxylin and eosin stained sections
(n=5 mice per group; mean±SD). (L, M) DNase I-coated nanoparticles inhibit NET-
mediated awakening of MCF-7 cells. (L) Mice with MCF-7 cells were treated as indicated
and monitored by BLI (n=5 mice per group; mean±SD). (M) Mice with MCF-7 cells were
treated as indicated, and metastatic burden in the lungs was quantified from hematoxylin
and eosin stained sections (n=5 mice per group; mean±SD). (N) Mice with D2.0R cells,
treated as indicated, were monitored by BLI. DNase I was first administered either at day
7 or day 14 and the treatment continued daily until day 33 (n=5 mice per group; mean±SD).
(O, P) Targeting NETs decreased neutrophil recruitment to the lungs. (O, P) Quantification
of neutrophils per field of view (n=3 mice; mean±SD).
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21
Fig. S5. NETs promote dormant prostate and breast cancer cell awakening.
(A) Kaplan-Meier curve representing the percentage of lung metastasis-free RapidCaP
mice treated as indicated (n=6 mice for the vehicle group, n=5 for the LPS group and n=4
for the LPS + PAD4 inh. Group, p=0.02, a Mantel-Cox log-rank test). (B) Representative
micrographs of RapidCaP cancer cells (red, stained for tdTomato) in DAPI-stained lung
sections Scale bar: 50 μm. (C) Histological phenotypes of cancer cells in lungs at end point
(110 days for mice with no BLI-detectable metastasis, p=0.02, Fisher’s exact test). (D)
Experimental design. MCF-7 cells were allowed to form primary mammary tumors and to
spontaneously disseminate for 6 weeks before we resected the primary tumors. Seven days
after resection, the mice were treated with LPS. (E) Mice with MCF7 cells, treated as
indicated, were monitored by BLI. (n=5 mice per group; mean±SD). (F) Representative
images of BLI at day 33. (G) Representative micrographs of MCF-7 cells (red) in Ki67
(green) and DAPI (blue)-stained lung sections at day 33. Scale bars: 50 μm. (H) Mice with
MCF-7 cells were treated as indicated, and metastatic burden in the lungs was quantified
from hematoxylin and eosin stained sections (n=5 mice per group; mean±SD). (I) Exposure
to tobacco smoke induced neutrophil recruitment to the lungs. Quantification of neutrophils
per field of view (TSP, total suspended particules). (J-L) Tobacco smoke exposure at 90
TSP mg/m3 induced NETs in the lungs of mice. (J) Quantification of NET-forming
neutrophils in the lungs of mice treated as indicated (n=3 mice; mean±SD). (K) ELISA
quantification of NETs in the plasma of mice treated as indicated (n=3 mice per group;
mean±SD). (L) dsDNA was quantified in the plasma of mice treated as indicated (n=3 mice
per group; mean±SD). (M) LPS was quantified in the plasma of mice exposed to tobacco
smoke as indicated. (n=3 mice per group; mean±SD). (N) Targeting NETs reduced tobacco
smoke exposure-induced awakening. Representative immunostaining of lungs at day 30
for D2.0R cells (red) and Ki67 (green) with DAPI (blue), treated as indicated. Scale bars:
50 μm.
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23
Fig. S6. Activation of neutrophils in vitro.
(A) D2.0R and MCF-7 cells were slow cycling on matrigel. Luciferase-expressing D2.0R,
D2.A1, and MCF-7 cells were cultured on matrigel for 15 days. BLI was used to quantify
cell number in the 3D cultures at indicated time points (n=3; mean±SD). (B) Representative
images of 3D culture show dormant D2.0R and MCF-7 cells and proliferative D2.A1 cells
after 15 days of culture. Scale bar: 100 μm. (C, D) Activation of neutrophils in vitro.
Immunostaining of mouse and human neutrophils (mPMNs (C) and hPMNs (D),
respectively) cultured as indicated. DAPI (blue), anti-MPO (red), and anti-histone H2B
(green) staining were used to assess NET formation. Scale bars: 100 μm. (E) NET-
containing Conditioned Media (CM) promote proliferation of dormant D2.0R cancer cells
on matrigel. Quantification of Ki67 positive D2.0R cells at day 14, cultured on matrigel
with the indicated treatment (n=3; mean±SD).
24
25
Fig. S7. Inducers of NETs have no direct effect on dormant cancer cell awakening,
while cigarette smoke extract induces NETs and awakening of dormant cancer cells.
(A-C) NET-containing CM induced awakening of MCF-7 cells in vitro on matrigel. (A)
BLI quantification over 15 days with indicated treatments (n=3; mean±SD). (B) BLI signal
at day 14 after indicated treatments. PAD4 inhibitor and DNase I were used during the
neutrophil culture to block or digest NET formation, respectively (n=3; mean±SD). (C)
Quantification of Ki67 positive MCF7 cells at day 14, cultured on matrigel with the
indicated treatment (n=3; mean±SD). (D, E) Factors that induce NETs and degranulation
have no effect on dormant cancer cells when added directly to cancer cell cultures. BLI of
luciferase-expressing D2.0R (D) and MCF-7 (E) cells, treated as indicated (n=3;
mean±SD). (F, G) Pretreatment of D2.0R cells with LPS before injection in vivo has no
effect on metastasis. (F) D2.0R cells were treated with LPS before injection into BALB/c
mice. Mice were monitored by BLI (n=5 mice per group; mean±SD). (G) Mice with D2.0R
cells were treated as indicated, and metastatic burden in the lungs was quantified from
hematoxylin and eosin stained sections (n=5 mice per group; mean±SD). (H) Activation
of neutrophils by Cigarette Smoke Extract (CSE) in vitro. Immunostaining of mouse
neutrophils cultured as indicated. DAPI (blue), anti-MPO (red), and anti-histone H2B
(green) staining were used to assess NET formation. Scale bar: 100 μm. (I) NET-
containing CM induced by cigarette smoke extract promoted awakening of D2.0R cells.
BLI signal at day 14 after indicated treatments. PAD4 inhibitor was used during neutrophil
culturing to block NET formation (n=3; mean±SD). (J) Cigarette Smoke Extract kills
cancer cells at high concentration. BLI of luciferase-expressing D2.0R cells, treated as
indicated (n=3; mean±SD).
26
27
Fig. S8. NET-associated neutrophil elastase (NE) and matrix metalloproteinase
(MMP) 9 activities in neutrophil conditioned medium (CM) promote awakening.
(A) NE and MMP9 were required for NET-induced awakening of MCF-7 cells in vitro.
BLI signal of luciferase-expressing MCF-7 cells 14 days after indicated treatments.
Cathepsin G (CG), NE, and MMP9 inhibitors were used during cancer cell culture (n=3;
mean±SD). (B, C) NE and MMP activities, measured with fluorescent probes, were
elevated in CM from neutrophils activated to form NETs. Quantification of NE (B) and
MMP (C) activities in the indicated neutrophil CM. The PAD4 inhibitor was used during
neutrophil culturing while NE and MMP9 inhibitors were added to the CM directly before
protease quantification (n=3; mean±SD). The samples for the vehicle condition were the
same as depicted in Fig. 4H as the experiments were done at the same time. (D)
Representative gelatin zymography of secreted MMP9 from PMNs cultured for 20 hours
as indicated (M.W., Molecular Weight). (E) Activation of NE and MMP9 Knock Out (KO)
neutrophils in vitro. Immunostaining of mouse neutrophils cultured as indicated. DAPI
(blue), anti-MPO (red), and anti-histone H2B (green) staining were used to assess NET
formation. Scale bar: 100 μm. (F) CM from NE and MMP9 KO neutrophils were not able
to induce awakening in vitro. BLI signal at day 14 after indicated treatments (n=3;
mean±SD).
28
29
Fig. S9. Neutrophil-derived Neutrophil elastase (NE) and matrix metalloproteinase
(MMP) 9 activities in inflamed lungs promote awakening.
(A, B) NE and MMP9 were highly expressed in neutrophils. Relative mRNA expression
of NE (A) and MMP9 (B) in D2.0R cells, D2.A1 cells, and neutrophils. (C) NET-
containing CM has no effect on expression of NE or MMP9 by D2.0R cells. mRNA
expression of NE and MMP9 in D2.0R cells treated as indicated. (D, E) mRNA expression
of NE (D) and MMP9 (E) in D2.0R cells expressing shRNA as indicated. (F) NET-
containing CM induced awakening of D2.0R cells expressing a NE or a MMP9 shRNA.
D2.0R cells expressing shRNA as indicated (two different sequences) were cultured on
matrigel for 14 days and proliferation was measured using the CellTiter 96 Aqueous One
Solution Cell Proliferation Assay from Promega (n=3; mean±SD). (G) Representative
gelatin zymography of secreted MMP9 from lung lysates of mice treated as indicated. (H,
I) NE and MMP activities were increased in LPS-treated lungs. NE (H) and MMP9 (I)
activity measured with fluorescent probes in lung lysates of mice treated as indicated (n=3
mice per group; mean±SD). (J) NE and MMP9 activities are required for NET-induced
awakening in vivo. Mice with D2.0R cells were treated as indicated, and metastatic burden
in the lungs was quantified from hematoxylin and eosin stained sections (n=10 mice for
vehicle and LPS groups; n=5 mice for LPS + NE inhibitor and LPS + MMP9 inhibitor
groups; mean±SD). (K) Quantification of neutrophils per field of view. (L) Experimental
design used to test the effects of NET-associated proteases on cancer cells vs. matrigel.
(M) BLI signal from luciferase-expressing D2.0R cells cultured on matrigel at day 14
under indicated conditions (n=3; mean±SD).
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31
Fig. S10. Laminin cleavage by NET-associated NE and MMP9 mediates dormant
cancer cells’ awakening in vitro.
(A, B) D2.0R and MCF-7 cells were slow cycling on laminin-111 in vitro. Luciferase-
expressing D2.0R (A) and MCF-7 (B) cells were cultured on laminin-111 for 15 days. BLI
at indicated time points was used to quantify cell number in the 3D cultures (n=3;
mean±SD). (C) Culturing on laminin-111 allows NET-dependent control of dormancy and
awakening. BLI signal of luciferase-expressing MCF-7 cells after 14 days at indicated
conditions (PAD4 inhibitor was used during PMN culture, n=3; mean±SD). (D, E) NET-
containing CM promoted proliferation of dormant cancer cells on laminin-111.
Quantification of Ki67-positive D2.0R (D) or MCF-7 (E) cells at day 14, cultured on
laminin-111 with the indicated treatment (n=3; mean±SD). (F) NET-containing CM
induced by Cigarette Smoke Extract (CSE) degraded laminin-111. Cleavage of laminin-
111 after incubation with indicated CM was detected by SDS-PAGE under reducing and
denaturing conditions and coomassie blue staining. (G, H) NE and MMP9 were required
for laminin-111 cleavage and awakening. (G) Experimental design used for studies
represented in Fig. 4, C and E, and fig. S10H. Laminin-111 was incubated with
recombinant proteases for 48 hours at 37 °C and then washed with medium before culturing
D2.0R cells on the remodeled matrix. BLI was used to quantify cell number after 14 days
of culture. (H) Laminin-111 was incubated with indicated recombinant proteases for 48
hours at 37 °C, and then washed with medium before culturing MCF-7 cells on the
remodeled matrix. BLI was used to quantify the number of cancer cells 14 days later (n=3;
mean±SD). (I) Addition of cleaved laminin-111 to the culture induces awakening. BLI
signal of luciferase-expressing D2.0R cells after 14 days at indicated conditions (J, K)
Both NE and MMP9 are required for laminin-111 cleavage. (J) Laminin-111 was incubated
with indicated recombinant proteases for six hours at 37 °C. Cleavage of laminin-111 was
monitored by SDS-PAGE under reducing and denaturing conditions and Western blot
using a laminin-111 antibody. (K) Laminin-111 was incubated with the indicated
neutrophil PMN CM and inhibitors for six hours at 37 °C. Cleavage of laminin-111 was
monitored by SDS-PAGE under reducing and denaturing conditions and coomassie blue
staining.
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33
Fig. S11. Multiple laminin isoforms and thrombospondin (TSP-1) can regulate
dormancy in vitro.
(A-C) Laminin-111 is present in the lungs of mice. (A) mRNA expression of all laminin
chains in the lungs of mice treated as indicated. (B) mRNA in situ hybridization of DapB,
lama1, lamb1 and lamc1 in the lungs of untreated mice. (C) Immunostaining of lungs
treated as indicated for DAPI (blue) and full-length laminin-111 (ab11575 from Abcam,
green). Scale bars: 50 μm. (D) Laminin is cleaved in the lungs of mice treated chronically
with LPS. Lung tissue lysate from mice treated as indicated was immunoblotted for
laminin-111 (LN-111). (E) NET-containing CM induced proliferation of quiescent MCF-
7 cancer cells cultured on human laminin (hLN)-111, -211, -411, and -511 as determined
by BLI after 14 days of culture (n=3; mean±SD). (F) NE and MMP9 both localize on the
DNA scaffold of NETs formed from LPS-treated murine neutrophils: DAPI (blue), NE
(green), and MMP9 (red). Scale bars: 50 μm. (G) dsDNA was quantified in the indicated
PMN CM. PAD4 inhibitor was used during neutrophil activation (n=3; mean±SD). (H)
NET-associated NE and MMP9 degraded TSP-1. TSP-1 was incubated with indicated
recombinant proteases or PMN CM for six hours at 37 °C. PAD4 inhibitor was added
during activation of PMN with LPS. Cleavage of TSP-1 was monitored by SDS-PAGE
under reducing and denaturing conditions followed by Western blot using a TSP-1
antibody. (I) Inhibiting NE and MMP9 activity did not prevent TSP1 cleavage.
Immunoblot of soluble TSP1 from lung tissue of mice treated as indicated. (J) Cleaved
TSP-1 was not sufficient to induce awakening. TSP-1 was incubated with indicated
recombinant proteases or PMN CM for 48 hours at 37 °C on 0.2 kPa hydrogel and then
washed with medium before culturing D2.0R cells on the remodeled matrix. BLI was used
to quantify the number of cancer cells 14 days later (schematic strategy represented in figs.
S9L and S10G) (n=3; mean±SD). (K, L) TSP-1 reduced NET-induced awakening.
Laminin-111 and TSP-1 were incubated with NET CM for 48 hours at 37 °C on a 0.2 kPa
hydrogel and then washed with medium before culturing D2.0R (K) or MCF-7 (L) cells on
the remodeled matrix. BLI was used to quantify the number of cancer cells after 14 days
of culture (n=3; mean±SD).
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35
Fig. S12. NET-induced awakening is associated with activation of the integrin 1
outside-in signaling pathway.
(A, B) NET-associated NE and MMP9 activated integrin 1 and proliferation in dormant
cancer cells. (A) Immunostaining of MCF-7 cells cultured on matrigel-coated 0.2 kPa
hydrogel as indicated for DAPI (blue), F-actin (red), active integrin 1 (green), and Ki67
(green). Scale bars: 50 μm. (B) rNE and rMMP9 were sufficient to activate integrin 1 and
proliferation in dormant cancer cells. Immunostaining of D2.0R cells cultured on matrigel-
coated 0.2 kPa hydrogel as indicated for DAPI (blue), F-actin (red), and active integrin 1
(green). Scale bar: 50 μm. (C) BLI of luciferase-expressing MCF-7 cells cultured on
matrigel after 14 days under indicated conditions (n=3; mean±SD). (D) Immunobloting of
integrin 1, FAK, MLCK, YAP, and Heat Shock Protein 90 (HSP90) on D2.0R cells, 48 h
after doxycycline-induced shRNA depletion, as indicated. (E-K) D2.0R cells were cultured
on matrigel for 10 days under indicated conditions (as described in Supplemental
Methods), and cell lysate was analyzed by Western blot. Immunobloting of phospho-FAK
(Tyr397), phospho-ERK 1/2 (Thr202/Tyr204), and phospho-MLC2 (pThr18/Ser19) was
performed to analyze activity of these proteins. Immunoblot of FAK, ERK 1/2, MLC2, and
HSP90 were included as controls.
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37
Fig. S13. Integrin 3 regulates NET-induced awakening and integrin signaling
knockdown does not kill dormant cancer cells in the lungs.
(A) D2.0R cells expressed integrin 3, 5, 6, 7, 8, 9 and v. D2.0R cells were stained for
integrin subunits as indicated and analyzed by flow cytometry. (B) Representative plots
of fluorescence intensity of indicated integrin staining in D2.0R cells expressing a control
shRNA or indicated integrin shRNA. (C) D2.0R cells expressing integrin shRNA as
indicated (two different sequences) were cultured on matrigel for 14 days, and proliferation
was measured using the CellTiter 96 Aqueous One Solution Cell Proliferation Assay from
Promega (n=3; mean±SD). (D) Integrin 1 and YAP knockdown did not kill dormant
cancer cells in the lungs. Representative micrographs of D2.0R cells (red) with DAPI-
staining (blue) in lung sections at day 33. Scale bar: 50 μm.
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39
Fig. S14. Cleaved laminin antibodies can be used to detect NET-mediated laminin
remodeling in vivo.
(A) Inhibiting NETs and their associated proteases prevented laminin cleavage in vivo.
Immunoblot of soluble laminin-111 from lung tissue of mice treated as indicated. (B)
Laminin-111 was incubated with recombinant proteases for six hours at 37 °C. The
proteolytically remodeled laminin-111 was purified away from the proteases using a 100
kDa molecular weight cut-off column. The presence of laminin-111, NE, and MMP9 in
each phase was then assessed using Western blot analysis under reducing and denaturing
conditions with specific antibodies. The upper fraction containing the cleaved laminin-
111 was next dialyzed in PBS and used to immunize rats. (C) Antibodies against NE and
MMP9-cleaved laminin prevented NET-mediated awakening and integrin 1 activation.
Immunostaining for active integrin 1 (green), F-actin (red), and DAPI (blue) of D2.0R
cells cultured on laminin-111-coated 0.2 kPa hydrogel under indicated conditions. Scale
bar: 50 μm. (D) Ab28 recognizes cleaved laminin-111 but does not recognize full-length
laminin-111. ELISA was used to measure the binding of antibodies Ab2, Ab19, Ab25,
and Ab28 to cleaved laminin-111, full-length laminin 111, or neutravidin (negative
control, n=3; mean±SD; OD, Optical Density) (E) Ab28 detected proteolytically
remodeled laminin in vivo. Lung sections from mice treated with LPS were
immunostained for full-length laminin-111 (ab11575 from Abcam, green) and cleaved
laminin (red) with DAPI (blue) to monitor binding of the generated antibodies to laminin
in vivo. Red arrows point to epitope recognized by Ab28 in lung tissue from LPS treated
mice. Scale bar: 50 μm. (F) Immunostaining of lungs for DAPI (blue), full-length
laminin-111 (green), and cleaved laminin Ab28 (red), in mice treated as indicated. Red
arrows point to epitope recognized by Ab28. Scale bars: 50 μm.
40
41
Fig. S15. Laminin epitope is detectable in the same lung tissue regions as NETs and
awakening cancer cells; antibodies against NET-remodeled laminin block awakening
after LPS- or tobacco smoke exposure-induced inflammation.
(A) The laminin epitope was detectable close to NETs in the lungs of mice with sustained
inflammation. Representative immunostaining for MPO (red), citrullinated histone H3
(green), cleaved laminin Ab28 (white) and DAPI (blue) in the lungs of mice treated as
indicated. Lower row shows only the Ab28 channel. Scale bar: 50 μm. (B, C) The laminin
epitope was detectable close to the awakened cancer cells. (B) Quantification of D2.0R
cells in G0/G1 (black bar) or S/G2/M (red bar), and clusters of cells (blue bar) close to
remodeled laminin (detected with Ab28) in the lungs of mice treated as indicated (n=3
mice; mean±SD; p<0.0001, Fisher’s exact test). (C) Representative micrographs of
sections of lungs with D2.0R cells expressing the FUCCI reporter (red, yellow and green)
stained with cleaved laminin Ab28 (white) and DAPI (blue), treated as indicated.
Individual channels are shown for all examples. Scale bar as indicated. (D) BLI of
luciferase-expressing D2.0R cells cultured on laminin-111, 14 days after indicated
treatment (n=3; mean±SD). (E) Antibodies against NET-remodeled laminin prevented
inflammation-induced awakening in vivo. Mice with D2.0R cells were treated as indicated,
and metastatic burden in the lungs was quantified from hematoxylin and eosin stained
sections (n=5 mice per group; mean±SD). (F) Antibodies against NET-remodeled laminin
prevented smoking-induced awakening in vivo. Representative immunostaining of lungs
at day 30 for D2.0R cells (red) and Ki67 (green) with DAPI (blue), treated as indicated.
Scale bars: 50 μm.
42
Movie Legends
Movie S1. Neutrophil infiltration and neutrophil elastase activity is low in the lungs
of control animals.
Lung intravital imaging of a LysM-EGFP BALB/c mouse treated with PBS and injected
with the NE 680 FAST probe was performed to analyze the presence of neutrophils and
neutrophil elastase activity in the lungs. Neutrophils express EGFP (green), NE activity is
represented in red, and DNA (blue) is labeled by injection of DAPI. Time indicated is time
(h:mm:ss) after imaging was initiated, 18 hours after PBS instillation. Representative of
three mice.
Movie S2. Intranasal instillation of LPS induces high neutrophil recruitment and
neutrophil elastase activity in the lungs.
Lung intravital imaging of a LysM-EGFP BALB/c mouse treated with LPS and injected
with the NE 680 FAST probe was performed to analyze neutrophil recruitment and
neutrophil elastase activity in the lungs. Neutrophils express EGFP (green), NE activity is
represented in red, and DNA (blue) is labeled by injection of DAPI. Time indicated is time
(h:mm:ss) after imaging was initiated, 18 hours after LPS instillation. Representative of
three mice.
Movie S3. D2.0R cells are dormant in the lungs of control animals immediately after
PBS instillation.
A BALB/c mouse injected intravenously with FUCCI D2.0R cells at day 0 was subjected
to lung intravital imaging at day 8, after PBS instillation on day 7. NE 680 FAST probe
was used to detect neutrophil elastase activity. D2.0R cells express the FUCCI reporter
(red, green, or yellow as represented in fig. S2D), NE activity is represented in purple (no
signal was detected), and DNA (blue) is labeled by injection of DAPI. Time indicated is
time (h:mm:ss) after imaging was initiated. Representative of three mice.
Movie S4. D2.0R cells remain dormant in the lungs of control animals after two
PBS instillations.
A BALB/c mouse injected intravenously with FUCCI D2.0R cells at day 0 was subjected
to lung intravital imaging at day 11, after PBS instillation on days 7 and 10. NE 680 FAST
probe was used to detect neutrophil elastase activity. D2.0R cells express the FUCCI
reporter (red, green, or yellow as represented in fig. S2D), NE activity is represented in
purple (no signal was detected), and DNA (blue) is labeled by injection of DAPI. Time
indicated is time (h:mm:ss) after imaging was initiated. Representative of two mice.
Movie S5. D2.0R cells remain dormant in the lungs of control animals 21 days after
injection.
A BALB/c mouse injected intravenously with FUCCI D2.0R cells at day 0 was subjected
to lung intravital imaging at day 21, after PBS instillation on days 7, 10 and 13. NE 680
43
FAST probe was used to detect neutrophil elastase activity. D2.0R cells express the FUCCI
reporter (red, green, or yellow as represented in Fig. S2D), NE activity is represented in
purple (no signal was detected), and DNA (blue) is labeled by injection of DAPI. Time
indicated is time (h:mm:ss) after imaging was initiated. Representative of three mice.
Movie S6. D2.0R cells enter the G1/S transition of the cell cycle 4 days after the first
LPS intranasal instillation.
A BALB/c mouse injected intravenously with FUCCI D2.0R cells at day 0 was subjected
to lung intravital imaging at day 11, after LPS instillation on days 7 and 10. NE680 FAST
probe was used to detect neutrophil elastase activity. D2.0R cells express the FUCCI
reporter (red, green, or yellow as represented in fig. S2D), NE activity is represented in
purple, and DNA (blue) is labeled by injection of DAPI. Time indicated is time (h:mm:ss)
after imaging was initiated; there is a gap in timeframes between 22 min and 1h 44 min
due to inability to obtain good focus during this time period. Representative of three mice.
Movie S7. Clusters of dividing D2.0R cells are present in the lungs of mice 7 days after
the first LPS intranasal instillation.
BALB/c mice injected intravenously with FUCCI D2.0R cells at day 0 was subjected to
lung intravital imaging at day 14, after LPS instillation on days 7, 10, and 13. NE680 FAST
probe was used to detect neutrophil elastase activity. D2.0R cells express the FUCCI
reporter (red, green, or yellow as represented in fig. S2D), NE activity is represented in
purple, and DNA (blue) is labeled by injection of DAPI. Time indicated is time (h:mm:ss)
after imaging was initiated. Representative of three mice.
Movie S8. Established proliferative metastasis of D2.0R cells are present in the lungs
of mice 14 days after the first LPS intranasal instillation.
BALB/c mice injected intravenously with FUCCI D2.0R cells at day 0 was subjected to
lung intravital imaging at day 21, after LPS instillation on days 7, 10, and 13. NE 680
FAST probe was used to detect neutrophil elastase activity. D2.0R cells express the FUCCI
reporter (red, green, or yellow as represented in fig. S2D), NE activity is represented in
purple, and DNA (blue) is labeled by injection of DAPI. Time indicated is time (h:mm:ss)
after imaging was initiated. Representative of three mice.
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