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Supplementarydatafor:Simple,mild,one-steplabellingofproteinswith68Gausingatris(hydroxypyridinone)
bifunctionalchelator:68Ga-THP-scFvtargetingtheprostatespecificmembraneantigen
SaimaNawaz,GregoryEDMullen,KavithaSunassee,JayantaBordoloi,PhilipJBlower,and
JamesRBallinger
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Methods
Proteinpurificationandanalysis
Sizeexclusionchromatography:PurificationofJ591c-scFvanditsTHP-malconjugatewas
performedusingFPLCsizeexclusioncolumnchromatographyusingaSuperdex7510/300
GLcolumn(GE),elutingwithphosphatebufferedsaline(pH7)ataflowrateof0.5ml/min
andmaximumpressureof1.8MPa.
PolyacrylamidegelelectrophoresisandWesternblottingwereusedtoevaluatepurityofthe
size-exclusion-purifiedJ591c-scFv,usingpre-castpolyacrylamidegels(NuPAGE12%Novex
Bis-TrisminigelswithMESbuffer,LifeTechnologies)andWesternblotting.Forthe
preparationofsamples,10µlaliquotsofJ591-scFvwereplacedinmicrocentrifugetubes
and5µlofNuPAGELDSloadingbuffer(4x)wasadded.Forreducedsamples,thereducing
agent(NuPAGEreducingagentofstrength10x,2µl)wasaddedalongwithNuPAGELDS
bufferof4xconcentration(5µl).Sampleswereplacedonaheatingblockfor5minat95oC
andthencooledonicefor1min.TheNuPAGEchamberswerefilledwiththeMESbuffer(50
mlof20xMESbuffer+950mlofdeionisedwater).Novexsharppre-stainedprotein
standardwasloadedinoneofthewells.Thegelwasrunfor40minatanominalvoltageof
200Vwithconstantcurrentof125mA,developedwithSimplyBlueSafeStain(Thermo
FisherScientific)for2handdestainedwithwaterovernight.Inthecaseofradiolabelled
proteins,beforestaining,activitymarkerswereplacedonthegelswhichwerethenimaged
withaphosphorimager.
ForWesternblotting,the12%gelwaspreparedasabove;insteadofstaining,thegelwas
loadedonanitrocellulosetransfermembraneanddevelopedinnon-reducingtransfer
buffer(NuPAGEtransferbuffer(20x)50ml+methanol(100ml)+deionisedwater(850ml))
for1hatconstant30Vandcurrentof170-130mA.After1hthetransfermembranewas
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removedandplacedinablockingagent(4%milkin50mlofPBSwith0.05%Tween20)for
90min,washedbrieflywithPBS,thenplacedinasolutioncontainingantibodyagainstHis-
tag(6.3µlofantibodydiluted(1:4000dilution)byadding25mlofPBSwith0.5%BSA,which
is0.125g/25mlofBSA)overnightat4oCwithshaking.Thetransfermembranewaswashed
fourtimeswith10mlofPBST(1lofphosphatebufferedsalinewith0.05%Tween20)before
incubatingwithsecondaryantibody(goatanti-mousehorseradishperoxidase)for60min
(1:5000dilution,approximately4µlofHRPin20,000µlofPBS).Thetransfermembranewas
washedwithPBSTfourtimesbeforeimmersingitinthesolutionofsubstrateDAB[(3,3-
diaminobenzidine)PeroxidaseSubstrateTabletSetfromSigmaAldrich](oneDABtabletand
oneUreaHydrogenPeroxidetabletdissolvedin15mlofultrapurewater).Thetransfer
membranewasdevelopedinthedarkuntilthebrown–blackprecipitationwasvisible.
Instantthinlayerradiochromatography(ITLC)
Proteinlabellingwithgallium-68wasassessedbyinstantthinlayerchromatography(ITLC)
usingITLC-SA(Agilent)developedwith0.1Msodiumcitratebuffer(pH6)asthemobile
phase.Undertheseconditionsunboundgallium-68movedwiththesolventfront(Rf=1)
andradiolabelledconjugatedproteinremainedattheorigin(Rf=0).
Highperformanceradiochromatography
Theradiolabelledproteinconjugateswereanalysedusingasize-exclusioncolumn(SEC-
2000),samplevolume20µl,elutingwithphosphatebufferedsaline(pH7),flowrate1
ml/min,UVdetectionat280nmandgammadetectionwithasodiumiodidedetector.
Serumstability
THP-J591c-scFv(200µl,0.4µg/µl)wasradiolabelledbyincubationwith300µlof68Ga
generatoreluate(60MBq)for20minatroomtemperatureandlabellingefficiencyfoundto
be>99%byITLC.Withoutfurtherpurificationormodification,theradiolabelledconjugated
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J591c(100µl)wasmixedwithserum(200µl)andphysiologicalsaline(100µl).Themixture
wasincubatedat37oCandsamples(5µleach)werecollectedat30,60,120,180,240and
300minandstoredat-80oCuntilallsampleshadbeencollected.Thebehaviourof
unchelatedGa-68inserumwasdeterminedbyincubating10µlofammoniumacetate
buffered68Gageneratoreluatewithserumasdescribedabove,incubatingforupto60min
at37oC,taking5µlsamplesandstoringthemat-80oCuntilallthetimepointswere
collectedforgelelectrophoresisanalysis.68Ga-THP-mal-J591c-scFvincubatedinsalineand
sampledsimilarlywasusedasareference.ForanalysisbySDS-PAGE,thesamples(5µl)
weremixedwith10µlofLDSbuffer(lithiumdodecylsulfate,pH8.4)andappliedonthegel
(10µl).ThegelwasdevelopedinMESbuffer(2-ethanesulfonicacid)for40minat200Vand
120-130A.Afterwardsthegelwasremoved,activitymarkerswereplacedanditwas
analysedbyphosphorimagerandthenstainedwithCoomassieblue.
PETimagingandquantification
Dynamicimaging(n=1eachgroup)wasperformedoverthetimeperiodof3hfromthe
timeofinjection,25daysaftertumourinoculation,usingaBioScannanoPET-CTPLUS
(Mediso)scannerusingtheirproprietaryacquisitionsoftware(Nucline,version2.00).CTwas
performedwithanx-raytubevoltageof45kVp,600msofexposuretime,and360
projections.Thisscantook10mintoobtain.DynamicPETscanswereacquiredwithina
94.7-mmfieldofviewfrom0to190minaftertailveininjectionofthetracer.Acquisition
tookplacein1–5coincidencemodewithacoincidencewindowof5nsanda400-to600-
keVenergywindow.ThedynamicPETdatawerereconstructedusingNuclinesoftware
(version2.00).Imageswereconstructedbasedon0.4mm3voxelsforPETand0.21mm3for
CT.ImageprocessingandanalysiswereperformedusingVivoquantsoftware(version1.23).
Beforeanalysis,bothCTandPETimageswererealignedandprocessedtoavoxelsizeof
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0.21mm3andthePEToutputcalibratedtodisplayMBqpervoxel.Regionsofinterest(ROIs)
foreachdatafilewereproducedusingfreehandsegmentation.SUVmaxvalueswere
obtainedfromregionsofinterestnearthecentreofeachselectedorgan/tumour,usingthe
totalactivitywithintheimage(excludingactivitywithinthetail)asthetotalinjecteddose.
Time–activitycurveswereproducedfrom15-minbins.
Results
SupplementaryTableS1.DeconvolutedelectrospraymassspectraofJ591c-scFvpre-and
post-reductionandconjugationwithTHP-mal.
Sample Deconvolutedmass Assignment
J591c-scFvpre-TCEPtreatment 27923 J591c-scFvcysteinedisulfideconjugate
J591c-scFvpost-TCEPtreatment 27804 J591c-scFvfreethiolform
THP-mal-J591c-scFv 28724 THP-mal-J591c-scFv
THP-mal 920.4 THP-mal
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SupplementaryFigureS1.ElectrospraymassspectraofJ591c-scFvpre-TCEPtreatment(top,27923.2correspondstodisulfideformedfromJ591clinkedtocysteineviaadisulfidebond);J591c-scFvpost-TCEPtreatment(middle,27803.9correspondstoJ591-scFv),andTCEP-treatedJ591-scFvafterincubationwithTHP-mal(bottom,28723.7correspondstoTHP-mal-J591-scFvadduct).
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SupplementaryFigureS2.TheeffectofdifferentmolarexcessesofTCEPondimerisationof
J591-scFv.Lanes:1:molecularweightmarkers;2:non-reducedprotein;3:reducedprotein
(NuPAGEreducingagent);4:0.4:1molarratioTCEP:protein;5:1:1molarratio;6:2:1molar
ratio;7:5:1molarratio;8:10:1molarratio;9:15:1molarratio;10:20:1molarratio;11:
30:1molarratio.
SupplementaryFigureS3.FPLCpurificationofTHP-mal-J591-scFvconjugateonSuperdex
75HR10/30sizeexclusioncolumnelutedwithphosphate-bufferedsalineat0.5ml/min.
ConjugateelutesbeforefreeTHP-mal.FreeTHP-malcanbeseenelutingat15-18min,
monomericTHP-conjugatedproteinat10min,anddimericproteinat8min.
60KDa
30KDa
Free THP-mal
THP-mal-J591c-scFv
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SupplementaryFigureS4.Exemplardatashowingradiolabellingefficiency(%proteinbound,determinedbyITLC)atdifferentproteinconjugateconcentrationsandtimes.Atconcentrationsof0.25mg/mlorhigher,labellingefficiencywas100%atalltimepointsfrom10sonward(thefirstdatapointineachseriesrepresentsasampletakenafter10sincubation).
0
20
40
60
80
100
120
0 500 1000 1500 2000 2500 3000 3500 4000
Timeandconcentrationdependenceofradiolabelling
%labelling, 0.25mg/ml %labelling, 0.125mg/ml
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SupplementaryFigureS5.SDS-PAGEanalysisofserumstabilityof68Ga-THP-mal-J591-scFv.
A:radioactivegelanalysedwithCyclonephosphorimager.B:gelstainedwithCoomassie
blue.Lanes:1:molecularweightmarkers;2:humanserumincubatedwithammonium
acetatebuffered68Gaeluate;3:Radiolabelled68Ga-THP-mal-J591-scFvconjugatecontrol
(withoutserumincubation);4:conjugateincubatedwithhumanserumfor1min;5:30min;
6:60min;7:120min;8:180min;9:240min;10:360min.
SupplementaryFigureS6.Time course of 68Ga-THP-mal-J591c-scFv activity (SUVmax) in
DU145-PSMA xenografts derived from serial images in a single mouse determined by PET
imaging. A region of interest near the centre of each organ was drawn from which SUVmax
was determined in each 15 min bin.
0 50 100 150 200 2500
2
4
6
791113151719
Urinary BladderTumour
Lt. kidney
LiverRt. Kidney
DU145-PSMA
min
SUV m
ax
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PSMA- PSMA- PSMA+ PSMA+organ ave SD ave SDblood 1.3 0.2 0.8 0.4tumour 0.5 0.2 5.4 0.5stomach 0.2 0.1 0.5 0.3smallintestine 0.4 0.1 0.6 0.2largeintestine 0.3 0.2 0.8 0.2spleen 3.0 1.4 3.4 0.7liver 3.4 1.5 4.9 1.1kidneys 41.5 12.7 89.3 10.0heart 0.6 0.1 1.5 0.3lungs 3.4 1.9 4.4 1.5trachea&thyroid 0.7 0.3 1.6 0.5salivarygland 0.4 0.2 0.9 0.2muscles 0.2 0.1 0.4 0.2bone 0.3 0.1 1.7 2.0reproductiveorgan 0.4 0.2 0.7 0.2tail 11.4 13.6 6.9 9.8skin&fur 0.6 0.3 0.8 0.2SupplementaryTableS2.Exvivobiodistributiondata(%ID/g)for68Ga-THP-mal-J591-scFvinmicebearingDU145(PSMA-)andDu145-PSMA(PSMA+)(meanandstandarddeviationareshown;n=4ineachgroup).
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SupplementaryFigureS7.Exvivobiodistributiondatafor68Ga-THP-mal-J591-scFvinmicebearingDU145(PSMA-,blue)andDU145-PSMA(PSMA+,red),90minpost-injection.Errorbarsrepresentstandarddeviation(n=4pergroup).Dataarethesameasthoseshowninthemainmanuscript(Fig.5)butexpandedtoincludekidneys.
0
20
40
60
80
100
120Exvivobiodistribution
PSMA- PSMA+