Tumor Immunology (1)

8/9/2019 Tumor Immunology (1)

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Imm n h r Imm n h r

-------- The battle between immune system and cancersThe battle between immune system and cancers

Dr Kevin Sun

Department of Molecular Medicine &Department of Molecular Medicine &PathologyPathology



• What is Cancer?• How does cancer occur?

• Current therapeutic strategies for cancers



Definitions of Cancer Definitions of Cancer

• clones of cells that are capable of

.

• Cancer cells arise from host cells vianeoplastic transformation or carcinogenesis.

• Ph sical chemical and biolo ical a entsmay cause cancer. -- carcinogens



Carcino ensCarcino ens• Radiation: Ultraviolet light, sunshine; X-rays,

radioactive elements induce DNA damage andchromosome brakes.

• Chemical: smoke and tar, countless chemicals

• Oncogenic viruses: insert DNA or cDNA copies

cells.• y: .



Neoplastic TransformationNeoplastic Transformation---- CarcinogenesisCarcinogenesis

• Activate growth regulatory genes : Growth factorreceptors (erbA, -B, fims, neu); molecules of signaltransduction (src, abl, ras); transcription factors (jun,fos ,myc)- referred to as oncogenes.

• Genes that inhibit growth: (p53 controls DNA repairan ce pro era on; -suppressor oncogenes.

• enes a regu a e apop os s: c - , ax, .



,

mucous membranes, epithelial cells in glands , . .

liposarcoma, fibrosarcoma’ ’- , - , ,

lymphomas; - solid tumors ,

myeloid, acute and chronic



cancerscancers

• ec an cs -- surgery,• Physics -- radiotherapy, 1896

• Chemistry -- chemotherapy, 1942• -- ,



for cancer for cancer

• Cancer cells are immunogenic• Single cell kill

• Memory• Specific

• -



Cancer Immunolo andCancer Immunolo andImmunotherapyImmunotherapy



• How does the immune system eliminate cancer cells?

• How can we help to win the battle between immune

sys em an cancers – ancer mmuno erapy• Examples



• e ypo es s was rs propose y r c n

1909, and modified by Thomas and Burnet in

• Immunosurveilance: the immunologicalresistance of the host against the development of

cancer.• Now referred to “cancer immunoediting”,

and escape.





Cells of the Immune SystemBone graft

Macrophage

Eosinophil

Mast cell

Basophil

Monoc te

Marrow

Hematopoieticstem cell

Bone

Multipotentialstem cellNeutrophil

Myeloidprogenitor

cell

ate ets

Lymphoid progenitor cell

T lymphocyte en r c ce

Natural killer cellB lymphocyte



Army of the host to fight cancersArmy of the host to fight cancers

Antibody

Macrophage

Cancer cellHelper T cell

cytokine

chemokineNK cell

Cytotoxic T cellDendritic cell





CD8+ T cells: attaching to class I MHC -peptide complex, they destroy cancer cells

enzymes or by triggering an apoptotic.

Surface

contactRelease ofenzymes



CD4+ T cells: reacting to class II MHC-

e tide com lex the secret c tokines.cytotoxic T cell response (Th1 helper T cells)

Logistics force



The professional antigen-presenting cells In the

na common pa way or ac va ng na ve

cells.Dendriticcell

T cell

-- ar y arn ng rcra

A novel subset of dendritic cells [IFN-producing killer DC] (IKDC):TRAIL& erforin- tumor cell l sis via T cell IFN -an io enesis



,

NKT cells: TRAIL/perforin- tumor cell lysis;IFNγ-angiogenesis

NK cell NKT cellacrop age



• Regulating the innate immune system: NK cells,,

system: T and B cells• - -- , ,

adhesion molecules; promoting activity of B and T cells,macrophages, and dendritic cells.

• IL-2 -- T cell growth factor that binds to a specific tripartitereceptor on T cells.- – ,

for B cells

• GM-CSF Granuloc te-monoc te colon stimulatin factor --reconstituting antigen-presenting cells.



Antibody Antibody -- produced by B cellsproduced by B cells• Direct attack : blocking growth factor receptors, arresting

proliferation of tumor cells, or inducing apoptosis.-- is not usually sufficient to completely protect the body.

• Indirect attack : -- major protective efforts1 ADCC antibod -de endent cell mediated c totoxicit -- recruiting cells that have cytotoxicity, such as monocytes and

macrophages.

-- binding to receptor, initiating the complement system,'complement cascade’, resulting in a membrane attack

, .

Heavy chain

Antigen-binding

region

-- missileAssembled antibody molecule

Constant region



Tumor elimination



cancer cell

Escape

Advanced cancer



CancerCancer

mmuno ogy mmuno erapymmuno ogy mmuno erapy• How does the immune system eliminate cancer cells?

• How can we help to win the battle between immunesys em an cancers – ancer mmuno erapy

• Examples



Mechanisms of cancer escape from

. er ng e r arac er s cs :Loss/downregulation of MHC class I

- , ,Loss of costimulation

2. Suppressing the Immune Response :

ineffective signals to CTL Alteration in cell death receptor signalingmmunosuppress ve cy o ne

3. Outpacing the Immune Response: Tumour cellscan sim l roliferate so uickl that the immuneresponse is not fast enough to keep their growthin check





(1) Loss/down(1) Loss/down- -regulation of HLAregulation of HLAclass I (MHC I)class I (MHC I)

• Total loss: 2 microglobulin mutation, alteration in

antigen processing machinery• Haplotype loss: LOH in chromosome 6

• HLA allelic loss: mutations of HLA class I enes

• HLA-A, B, C locus down-regulation: alteration of

• Compound phenotype: 2 or more independentmec an sms



(2) Down(2) Down- -regulation, mutation or loss ofregulation, mutation or loss of

tumor antigenstumor antigens

Tumor antigens (TA)Tumor associated antigen (TAA)

• Complete loss• Down-modulation



Tumor Anti ensTumor Anti ens• Altered self: K-ras, products of normally unexpressed

, , ,reading frame, - of post-translational modification, -

different orders of l cos lation mucin-CA125 MUC1 .• Viral antigens: EBNA, E-6,E-7, papilloma virus antigens

of cervical carcinomas.

• Oncofetal antigens : alpha-fetoprotein (AFP),Carcinoembryonic antigen (CEA)• - - ,

leukemias; HER-2/neu epidermal growth factor receptor-

breast cancer (Herceptin).



.B7.2(CD86) B7 family

CD27, CD30

-OX40

-







receptor signallingreceptor signalling

• resistance to apoptosis

• Apoptosis resistance: overexpressionof Bcl-2



(5) Immunosuppressive(5) Immunosuppressive

cytokinescytokines• .• IL-10 inhibits antigen presentation and IL-12

.• TGF-beta induces overproduction of IL-10.

• VEGF (vascular endothelial growth factor),avoid immune recognition, inhibit theeffector function, prevent T cell activation,

cytokine production.





(6) Induction of(6) Induction of

Immunosuppressive cellsImmunosuppressive cells• CD4+CD25+ T cells (constitute 5-10% of CD4+ T cells):

immunological tolerance to self-antigens, inhibition of T cellpro era on.

• Gr1+CD11b+ myeloid cells:-- Expressing the granulocyte-monocyte markers Gr1+CD11b+,accumulate in spleens, lymph nodes and blood of tumor-bearing mice.-- n ng an o y pro uc on, genera on, cefunction, lymphocytic proliferation, CD3 chain expression.





sources forregulatory

Possible suppressive mechanisms regulatory T cells



Possible suppressive mechanisms regulatory T cells



7 Production of other7 Production of othersuppressive factorssuppressive factors

• IDO (Indoleamine 2, 3-dioxygenase):

and splenic DC subsets, leading to

• ganglioside (sialic acid containingy

• Prostaglandins

S i d f f hS i d f f h



Summary: Main defences of theSummary: Main defences of the

tumors against immunitytumors against immunity

2) Dysregulated expression of adhesion / costimulatory

3) Changes in T-cell signal transduction molecules, i.e. cell death

4) Induction of immune suppressive cytokines

5) Induction of immunosuppressive cells

6) Secretion of suppressive factors



1. Weapons from the tumors

2. Defects of immune system



• Immune defects in T cells

• Malfunction of dendritic cell s stem





Tumor mass

Vessel

Lymphocyte

FasL+ tumor cell

Apoptotic lymphocyte

Receptor-mediated apoptosis of lymphocytes



– Tumor-mediated inhibition of DC generation,

– Functional impairment of DCs: lack of

– Induction of DC apoptosis by tumors



Tumor Tumor- -derived factors with DC inhibitory propertiesderived factors with DC inhibitory properties

Tumor-derived factors Effect on DCs

VEGF tumor infiltration and generation

TGF-beta CD80 and CD86 expressionGangliosides inhibition of dendropoiesis from

hematopoietic precursor cells

-

IL-10 differentiation,CD80/CD86/CD40expression,IL-12 production

Prostanoids,prostaglandins differentiation

PgE2 generation

NO induction of apoptosis



Summary

How do tumors progress?



Activation versus suppression of



pp

TumorRegression

Cytokines

Activation >suppression

T cellTumor

Suppression> activation

TumorProgression

DCNK cell



de ends on the battle between

immune system and tumor cells







Strategies to improve the tumor-

either boosting components of the

effective immune response or byinhibiting components that suppress

the immune response.

ImmunotherapyImmunotherapy --- --- ReverseReverse



ImmunotherapyImmunotherapy ReverseReverse

the imbalancethe imbalance

Tumor Immunotherapy

Tumor Progression

StrategiStrategiees to supplement the missing ors to supplement the missing or



St ategSt ateg ees to supp e e t t e ss g os to supp e e t t e ss g o

insufficient immune elementsinsufficient immune elementsImmune elements Enhancing ‘the enhancer’

T cells Injection of cytotoxic T cells

Natural killer cells Injection of activated NK cells

TAA Peptide, TAA-vector vaccination

Effector cytokines IL-2, IL-12

Strategies to block the suppreStrategies to block the suppresssive sive



Strategies to block the suppreStrategies to block the suppresssive sive

mechanismsmechanismsSuppressive elements Inhibiting ‘the inhibitors’

Regulatory T cells Blocking their function

dysfunctional DCs Blocking the pathway

Suppressive cytokines Blocking potential commoncy o ne s gna ng

Main Mechanisms ofMain Mechanisms of



ImmunotherapyImmunotherapy• Stimulatin the antitumor res onse either b increasin the number of effector cells or by producing solublemediators.

• Decreasing suppressor mechanisms.

• Altering tumor cells to increase their immunogenicity and.

• Im rovin tolerance to c totoxic dru s or radiotherasuch as stimulating bone marrow function with GM-CSF.



• - o ey o serve umour regress onafter bacterial infections

• BCG vaccine to treat bladder carcinoma• 1970-80’s – c tokines

– includes interferons, interleukins and tumor

– Limited success

Current ImmunotherapeuticCurrent Immunotherapeutic



pp

strategies in clinic or clinical trialsstrategies in clinic or clinical trials

• Antibody Therapy• Cytokine Therapy• • Vaccination• Combinational therapy



ExamplesExamples

ntibod Therantibod Thera



ntibod Therantibod TheraRituximab: The first approved antibody by FDA in clinical trial.Targeting CD20. low-grade non-Hodgkin lymphoma



Local and regional IL-2 administration in cancer patients -selected examples from the early trials



p y

Interleukin-2 Dose Tumour Response (%) Referenceun s pa en omp e e par a

gibbon lymphoid 1.5 x 10-2 – 4.0 x 10-3 urinary bladder carcinomas 30/ 30 Pizza (1984)

human recombinant 1.0 x 10-4 – 2.8 x 10-4 lung carcinomas 0/ 82 Yasumoto (1987)

human recombinant 8.0 x 10-2 – 5.4 x 10-3 malignant gliomas 13/ 13 Yoshida (1988)human lymphoid 2.0 x 10-3 squamous cell carcinomas 29/ 29 Forni (1988)human lymphoid 2.0 x 10-3 squamous cell carcinomas 30/ 30 Cortesina (1988)human lymphoid continuous perfusion urinary bladder carcinomas 20/ n.v. Huland and Huland

1.5 x 10-6/week (1989)

n.v., not verified because of incomplete transurethral resection



• Stimulating immune cells by exposing

laboratory and then injecting expanded

patients. .

Tumor escape mechanism and T-cell adoptiveimmunotherapy after genetic manipulation



(1) Tumor cells that produce TGFß that exert inhibitory effects on the immune system. Specific CTL can be geneticallymodified to become resistant to the TGF β inhibitory effect through transgene expression of a mutant dominant-negat ve type receptor .

(2) Specific T cells genetically modified to produce IL-12 can overcome IL-10 inhibitory effect.

(3) Tumors express FasL and induce apoptosis of effector T cells. Small interfering RNA (siRNA) can be used toknock-down Fas receptor in specific CTL, allowing a significant reduction of their susceptibility to Fas/FasL-

.

Adoptive immunotherapy Adoptive immunotherapy



Generation of dendritic cell vaccines from eri heral blood monoc tes:1) Monocytes cultures with GM-CSF +IL-4 to produce DCs2) Matured with CD40 ligand3) Pulsed with peptide or tumour lysate

4) Re-injected as vaccine to induce T-cell immune response against tumour



Antitumor Vaccines Antitumor Vaccines

of antigen to induce a specificof antigen to induce a specifican umour mmune response.an umour mmune response.

Antitumor Vaccines Antitumor Vaccines





Approaches to antitumor vaccination Approaches to antitumor vaccination



The Journal of Clinical Investigation Vol 113 ( 11) June 2004 pp 1515

APC – antigen presenting cell TAA – tumour associated antigen

DC – dendritic cell MHC – major histocompatibility complex

Dendritic Cells That Attack Cancer Dendritic cell

Complex binds matures and is



Complex binds

to dendritic cellprecursor

matures and is

infused back intopatient

T cell

Tumor antigen

antigen islinked to acytokine

Complex istaken in bydendritic cellprecursor

Cancer cell

T cells attack cancer cell









The immune system can be harnessed,

but only if immunotherapy is combinedwith treatment strategies that target atumour’s wea ons of survival defence

and attack. If cancer cells are prevented

generate immune escape variants.

--



enhances the therapeutic efficacy of cancer immunotherapyenhances the therapeutic efficacy of cancer immunotherapy

, . -

Potential mechanisms for synergy displayed by combined blockinghypoxia pathway and B7.1-mediated immunotherapy



B7.1+AS-HIFAS-HIFNK .

Tumor cell

Apoptosis Necrosis Glycolysis

ActivatesNK cells

v

cell Tumor cell

hs 70- tumor

Anti-angiogenesis

vv

APCCTumor

cellB7.1

Antigen

Heat-shock Cell vitality.

MHCIICD28

MHCI

CD28

T cell

MHCII

T cell

driven anti-tumor

immunity

Immune su ressive

Proliferation& CTL-

mediatedkilling

elements

Tumor Cell

Apoptosis

B7H3-meidated Cancer Immunotherapy



Arsenic trioxide synergizes with B7H3-mediatedimmunotherapy to eradicate hepatocellular carcinomas

International Journal of Cancer 2006; 118:1823-1830.

omp e e era ca on o epa oce u ar carc nomas y com ne

vasostatin gene therapy and B7H3-mediated immunotherapy.-

Novel co-stimulatory molecule- B7H3



Molecular Structure

SS IgV-like IgC-like Cytoplasmic

Signal peptideMLRGWGGPSVGVCVRTALGVLCLCLTGAVEVQVSEDPVVALVDTDATLRC

I V-like domain

Transmembrance

SFSPEPGFSLAQLNLIWQLTDTKQLVHSFTEGRDQGSAYSNRTALFPDLLVQ

GNASLRLQRVRVTDEGSYTCFVSIQDFDSAAVSLQVAAPYSKPSMTLEPNK IgC-like domain

VHSVLRVVLGANGTYSCLVRNPVLQQDAHGSVTITGQPLTFPPEALWVTVGTransmembrane Cytoplasmic

LSVCLVVLLVALAFVCWRKIKQSCEDENAGAEDQDGDGEGSKTALRPLKPS

ENKEDDGQEIA

, . .

Gene transfer results in expression of B7H3 on



pcDNA3.1 Flag-B7H3

Flag-B7H3

Tubulin

Combinational thera led to eradication of lar e tumors



and generation of memorized anti-tumor immunity

2

2.4

e ( c m

)

B7H3+ As2O 3

B7H3As 2O 3

pcDNA3.1PBS

0.8

1.2

.

T u m o r

S i z

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.

0 1 2 3 4 5 6 7 9 12Weeks After Therapy

20

Production of anti-tumor cytokine and CTLs by immunotherapy

500m l )

10m l )



400 -

( p g / m

* * Sera 8 -

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L e v e

l o

f I F

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• Immunotherapy may be the next great hope forcancer treatment.

• individually shown some promise, it is likely that

attack on all fronts.

traditional cancer therapies is another avenue.

Background – mini review

Controversial Not reported Shortcomings



Unclear Further investigationIntroduction

Hypothesis

Experiments

Materials and Methods

Results

Discussion

ConclusionDiscussion Combined

Future Investi ation

gn cance



DR Kevin Sun

Rm 4231Tel:3737599-85935Email:k.sun auckland.ac.nz

Tumor Immunology (1)

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