Immunotherapy and cancer Flashcards

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1
Q

What are some immune modulators?

A
  • Coley’s toxins
  • cytokines
  • pattern recognition receptor agonists
  • HSP
  • ab therapy
  • inflammation
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2
Q

What are coleys toxins?

A
  • strep pyogenes and serratia marcesens
  • unsure of mechanism of action
  • potentially TNF, streptokinase or PAMPs
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3
Q

What is BCG?

A
  • bacillus calmette-guerin
  • vaccine for TB
  • good immunological adjuvant
  • stimulates the innate immune system TLRs
  • used in bladder cancer
  • mechanism of action - DC activation, NK activation
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4
Q

Describe the cytokine : interferon

A
  • type 1 interferon (a and b)
  • produced by virally infected cells
  • viral detection pathways within most cells
  • upregulates MHC class I, tumour antigens and adhesion molecules
  • activates T cells and B cells and DC
  • used in metastatic melanoma
  • bad side effects
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5
Q

Describe the cytokine: interleukin 2

A
  • t cell growth factor
  • success in RCC and melanoma
  • toxicity
  • LAK cells, PBMC treated with IL-2 and re-infused into patients
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6
Q

Describe the cytokine: GM-CSF

A
  • stimulates APC
  • trialled in melanoma
  • may benefit in conjunction with IL-2
  • others: IL-4, IL-1. IL-7
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7
Q

What is the success rate of cytokine therapy?

A
  • interferons - 10-20%
  • IL-2 - 10-20%
  • IL-2+interferons - 40%
  • GM-CSF+IL-2 - 20%
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8
Q

What is pattern recognition?

A
  • intra and extra cellular sensors - pathogen associated molecular patterns (PAMPs)
  • conserved between species
  • 4 families :
  • toll-like receptors
  • nucleotide-binding oligomerisation domain (NOD) like receptors
  • retinoic acid inducible gene (RIG) like receptors
  • DNA sensors
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9
Q

Describe PRRs

A
  • originally thought of as sensors for infection - but more recently receptors for endogenous ligands
  • Danger associates molecular patterns (DAMPs_
  • recognise cell injury, stress or cell death
  • eg. HSP, HMGB1
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10
Q

What are toll-like receptors?

A
  • pattern recognition molecules for bacterial and viral ligands
  • most mammalian sp : 10-15
  • stimulate cytokine release
  • amplify the immune response
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11
Q

Describe TLRs in cancer therapy

A
  • BCG (TICE) used as adjuvants TLR2 and 4 - mostly used in bladder cancer
  • MPLA (monophosphoryl lipid A), lps, TLR4 agonist
  • stimuvex - MUCI peptide and AS04 used in NSCLC
  • detox - MPLA and myco cell wall used with peptide vaccines in metastatic cancer
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12
Q

Describe intracellular PRRs

A
  • poly I: C synthetic dsRNA, direct effect on tumour causing cell death - induction of apoptosis
  • also activated the immune response
  • used in glioma, prostate, breast and melanoma
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13
Q

What are heat shock proteins HSP?

A
  • some HSP are stress inducible, others are consitutively expressed
  • some HSP are upregulates by a specific stress type, others by many types of stress
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14
Q

What are heat shock proteins HSP?

A
  • some HSP are stress inducible, others are constitutively expressed
  • some HSP are upregulates by a specific stress type, others by many types of stress
  • effects the adaptive immune system - processing of peptide for presentation
  • innate immune system - cytokine production and upregulation of co-stimulatory molecules
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15
Q

Describe the therapeutic uses of HSP in cancer

A
  • HSP is increased in tumour tissue
  • at present there are - 150 centres looking at therapeutic uses
  • most randomised trials
  • data = suggestive
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16
Q

What are the major approaches of therapeutic antibodies?

A
  • direct anti-tumoural ie blockade of growth signals and induction of apoptosis
  • immunomodulation
    delivery system
17
Q

How are growth factors blocked?

A
  • trastuzmub (herceptin) - targets ERBB2 on breast cancer cells - blocks ERBB2 signalling and allows targeting of ADCC
  • bevacizumbab (avastin) targets VEGF and blocks signalling, used in colon cancer
18
Q

How is apoptosis induced?

A
  • rituximab - anti-CD20, used for CD20 positive B cell Non-hodgkins lymphoma and CLL
  • alemtuzumsb (campath) - anti CD52, used for B-CLL
19
Q

What are some antibodies used in immunomodulation?

A
  • ipilimumab (anti- CTLA-4) blocks the inhibition due to CTLA-4 signalling = used in metastatic melanoma
20
Q

How can different delivery methods be used for antibody therapy?

A
  • yttrium-labelled ibritumomab tioxetan ab to CD20 delivering radiotherapy to follicular b-cell NHL
  • brentuximab vedotin - ab to CD30 delivering toxin to CD30 + b cells in BHL
21
Q

Describe checkpoint inhibition

A
  • blockade of effector cell death
  • ab against PD-1 (programmed cell death protein 1)
  • expressed on T cells and can induce apoptosis when bound to PDL-1
  • PDL-1 can be found on tumour cells
  • nivolumab and pembrolizumab
  • combination therapy with ipilimumab
22
Q

Why is inflammtion bad?

A
  • regulation of the immune response
  • tregs induced which turn off response
  • myeloid derived suppressor cells/M2 cells
  • Th2 switch
  • NKT cells make IL-13 which induce myeloid cells to produce TGF-beta
  • Th1 response is good = resolve tumour
  • Th2 will not