Cancer immunotherapy and gene therapy

1. Cancer Immunotherapy and Gene Therapy
Arkaprava Roychaudhury
RA1612024010001

2. Cancer Immunotherapy

3. Introduction
• Immunotherapy, also called biologic therapy or biotherapy is the use of the
immune system to reject cancer. The main premise is stimulating the patient’s
immune system to attack the malignant tumor cells that are responsible for the
disease.
In the late 1800s, Dr. William Coley noted that getting an infection surgery
seemed to help some cancer patients. He began treating cancer patients by
infecting them with certain kind of bacteria known to be as Coley toxins.
Cancer Immunotherapy and Gene Therapy

4. Introduction
Immunosurveillance and Immunoediting
• In 1909, Paul Ehrlich proposed that the incidence of cancer would be much
greater were it not for the vigilance of our immune defense system in identifying
and eliminating nascent tumor cells.
• About 50 years later, two scientists, Lewis Thomas and Frank MacFarlane Burnet,
took Paul Ehrlich’s original idea a step further and proposed that T cell was the
pivotal sentinel in the immune system’s response against cancer.
• This elaboration led to the coinage of the term “immune surveillance or
immunosurveillance” to describe the concept whereby the immune system is on
perpetual alert against transformed cells.
Cancer Immunotherapy and Gene Therapy

5. Introduction
• Osías Stutman showed in the 1970s that mice supposedly lacking an intact
immune system (so-called nude mice) did not become more susceptible to tumor
growth as predicted by the theory.
• Thus, the theory of immunosurveillance remained controversial until an
important scientific article was published in Nature on April 26, 2001. The paper
unambiguously showed that the immune system can and often does prevent
tumors from developing, and thus plays a strong protective role against cancer.
These researchers also uncovered important new insights regarding the immune
system and tumor development that they coined immunoediting.
Cancer Immunotherapy and Gene Therapy

6. Introduction
Cancer Immunotherapy and Gene Therapy

7. Types of Immunotherapy
• Dendritic Cell Vaccines
• Antibody Therapy
• Cytokine Therapy
• Adoptive T cell Therapy
• Immune checkpoint blockade
• Combined Therapy
Cancer Immunotherapy and Gene Therapy

8. Dendritic Cell Vaccines
Why DCV?
• CD8+ cytotoxic T lymphocytes (CTLs), are the principle effectors of anti-tumor immunity.
• CTLs become sensitized to Ag by encountering peptide-class I MHC on the surface of professional
APCs.
• But this is not sufficient to activate the effector response. CD4+ T helper cells must also be
present to recognize peptides displayed on the class II MHC molecules of the APCs.
• This results in secretion of Cytokines by TH cells that - expansion and maturation of CTLs.
• Coexpression of co-stimulatory molecules, such as CD80/B7.1 and CD86/B7.2, by the APCs is also
required to deliver a second confirmatory signal to the T cells via the CD28 molecule expressed on
their surface.
• No co-stimulatory signals - T-cell anergy and is a mechanism for maintaining peripheral tolerance
to self antigens.
Cancer Immunotherapy and Gene Therapy

9. Dendritic Cell Vaccines
Tumor Antigens recognized by T cells
Cancer Immunotherapy and Gene Therapy

10. Dendritic Cell Vaccines
• DC are activated in the presence of tumor antigens, which may be a single tumor-
specific peptide/protein or a tumor cell lysate (a solution of broken down tumor
cells).
• Activated dendritic cells are put back into the body where they provoke an
immune response to the cancer cells.
• Adjuvants are sometimes used.
• More modern dendritic cell therapies include the use of antibodies that bind to
receptors on the surface of dendritic cells. Antigens can be added to the antibody
and can induce the dendritic cells to mature and provide immunity to the tumor.
• clinical response takes time to build up but remissions can be very long-lasting.
Targeting antigens to DCs Ex vivo
Cancer Immunotherapy and Gene Therapy

11. Cancer Immunotherapy and Gene Therapy
Dendritic Cell Vaccines

12. Dendritic Cell Vaccines
Targeting antigens to DCs Ex vivo
• Treatment of metastatic prostate cancer with sipuleucel-T (also known as APC 8015),
which is a cellular product based on enriched blood APCs that are briefly cultured
with a fusion protein of prostatic acid phosphatase (PAP) and GM-CSF
• An approximately 4-month-prolonged median survival in Phase III trials.
• Sipuleucel-T has been approved by the US Food and Drug Administration (FDA)
Cancer Immunotherapy and Gene Therapy

13. Dendritic Cell Vaccines
Targeting antigens to DCs Ex vivo
Cancer Immunotherapy and Gene Therapy

14. Dendritic Cell Vaccines
Vaccines under clinical trial
Targeting antigens to DCs Ex vivo
Cancer Immunotherapy and Gene Therapy

15. Dendritic Cell Vaccines
• Using chimeric proteins that are comprised of an Ab that is specific
for a DC receptor fused to a selected antigen.
• Ralph Steinman and colleagues demonstrated that the specific
targeting of antigens to DCs in vivo elicits potent antigen-specific
CD4+ and CD8+ T cell-mediated immunity.
• They activated two subsets of DCs : CD8+ DCs & CD8– DCs.
Targeting antigens to DCs in vivo
Cancer Immunotherapy and Gene Therapy

16. Dendritic Cell Vaccines
Targeting antigens to DCs in vivo
Cancer Immunotherapy and Gene Therapy

17. Dendritic Cell Vaccines
Targeting antigens to DCs in vivo
Cancer Immunotherapy and Gene Therapy

18. Antibody Therapy
• Ab therapy targets cancer antigents or Neoantigents.
• Ideally, the target antigen should be abundant and accessible & should be
expressed homogeneously, consistently and exclusively on the surface of cancer
cells.
• Mainly kills cells by complement-dependent cytotoxicity (CDC), antibody-
dependent cellular cytotoxicity (ADCC).
• Killing can result from direct action of the antibody, immune-mediated cell killing
mechanisms, payload delivery, and specific effects of an antibody on the tumor
vasculature and stroma.
Cancer Immunotherapy and Gene Therapy

19. Antibody Therapy
• Naked Monoclonal Abs - Antibodies without modification. Most of the currently used
antibodies therapies are naked.
• Conjugate Monoclonal Abs - Abs are conjugated with toxins or radioactive compounds
to properly deliver the conjugant.
• Four types of monoclonal antibodies based on source:
• Murine : antibodies were the first to be produced, and carry a great risk of immune
reaction, because the antibodies are from a different species.
• Chimeric : the first attempt to reduce the immunogenicity. murine Abs with a specific
constant region replaced with the corresponding human counterpart.
• Humanized : almost completely human; only the complementarity determining regions
of the variable regions are derived from murine.
• Human antibodies have completely human origin.
Types of Antibody therapy
Cancer Immunotherapy and Gene Therapy

20. Antibody Therapy
• Haematopoietic differentiationantigens – CD20, CD30, CD33, CD52.
• Glycoproteins expressed by solid tumour – Mucins , EpCAM-epithelial cell
adhesion molecule.
• Glycolipids – Gangliosides such as GD2, GD3 and GM2.
• Carbohydrates – Lewis Y Ag expressed by 42% squamous cell lung carcinoma, 80%
lung adenocarcinoma, 25% ovarian carcinoma, colorectal adenocarcinoma.
Targets in Cancer
Cancer Immunotherapy and Gene Therapy

21. Antibody Therapy
Direct Tumor cell Killing
Cancer Immunotherapy and Gene Therapy
Mechanism of Action

22. Antibody Therapy
Cancer Immunotherapy and Gene Therapy
Immune – mediated killing

23. Antibody Therapy
Vascular and stromal cell ablation
Cancer Immunotherapy and Gene Therapy

24. Antibody Therapy
Nivolumab
• A human IgG4 anti-PD-1 monoclonal antibody developed by Ono Pharmaceutical and Medarex
• Inhibitory ligand blocking antibody against the programmed death receptor
• PD-1 is a protein on the surface of activated T cells. If the ligand PD-L1 or PD-L2 binds to PD1,
the T cell becomes inactive.
• This is one way that the body regulates the immune system, to avoid an overreaction.
• Many cancer cells make PD-L1, which inhibits T cells from attacking the tumor.
• Nivolumab acts by blocking PD-1 of T-cell activation and response , thus allowing the immune
system to attack the tumor
• Uses: Metastatic melanoma, Lung cancer, Hodgkin's lymphoma

25. Antibody Therapy
PET-CT scan showing
localisation of 124Ilabelled
cG250 (carbonic
anhydrase IX (CAIX)-
specific) monoclonal
antibody, obtained 5 days
after antibody infusion.
The specific uptake of the
antibody can be seen in
the left renal tumour
(arrow), which is
expressing CAIX antigen.

26. Cytokine Therapy
• Cytokines are secreted or membrane-bound proteins.
• Significance in immunosurveillence:- higher frequency of
spontaneous cancers seen in mice.
• Genetically deficient in type I or II IFN receptors or elements of
downstream IFN receptor signal transduction.
• IL-2 & IFN-α have been used to treat advanced melanoma & renal
cell.

27. • IFN-α
1. Secreted by nearly every cell in the body and involved in cellular immune responses
against viral infections.
2. Type I-IFNs induce expression of MHC class I molecules on tumor cells and mediate
the maturation of a subset of DC.
3. Can also activate CTLs, NK cells and macrophages.
4. IFN- α is the only currently approved adjuvant therapy for patients with high-risk Stage
II or Stage III melanoma.
5. Also approved for the treatment of some hematologic malignancies, AIDS-related
Kaposi’s sarcoma, and as a component in an anti-angiogenic combination regimen
with bevacizumab for advanced renal cancer.
6. IFN-α has dose related toxicity, can leads to depression, confusion, mania and other
neuropsychiatric diseases. High doasages may coause permanaent alternation of
immunesystem causing vitiligo and hypothyroidism.
Cytokine Therapy
Type I Interferons

28. • IFN-β
1. Produced by leukocytes but also by some tumors.
2. Comparatively, IFN-β is more potent than IFN- α in inducing
antiproliferative effects in cancer models.
3. Usage is limited due to substantial side effects.
Cytokine Therapy
Type I Interferons

29. • IFN-γ
1. Role in immunosurveillance : Mice with targeted deletion of IFN or
the Type II IFN receptor have an increased risk of spontaneous and
chemically-induced tumors compared to controls.
2. Cytotoxic to some malignant cells and has modest anti-angiogenic
activity.
3. IFN- has demonstrated very limited clinical utility in cancer therapy.
Cytokine Therapy
Type II Interferons

30. • IL-2 plays a pivotal role in the treatment of patients with metastatic
melanoma and renal cell carcinoma.
• National Cancer Institute found that adoptively transferred IL-2-activated
peripheral blood mononuclear cells with administration of IL-2 in high
doses, resulted insignificant tumor regression in patients.
• It promotes both effector T cells and T-reg cells, but its exact mechanism in
the treatment of cancer is unknown.
• Side effects: capillary leak syndrome, which is characterized by
hypotension, tachycardia and peripheral edema secondary to third space
fluid accumulation, fever, chill and fatigue, gastrointestinal side effects such
as nausea, vomiting, anorexia, cholestasis and diarrhea.
• IL-2 reported a 2% mortality rate.
Interleukin 2
Cytokine Therapy

31. Adaptive T cell therapy
• Isolate antigen-specific T cells from a cancer patient, expand them to
large numbers in a testtube and re-infuse them back into the patient
to kill off the remaining tumor cells.
• Cells are Harvested from a variety of sites, including peripheral blood,
malignant effusions, resected lymph nodes, and tumor biopsies.
• Tumor-infiltrating lymphocytes (TILs) obtained from biopsies may
contain a higher frequency of tumorreactive cells.
• T cells can be expanded through polyclonal stimulation with
activating antibodies or through exposure to specific tumor antigens

32. Adaptive T cell therapy

33. Adaptive T cell therapy

34. • A particularly important immune-checkpoint receptor is cytotoxic T-lymphocyte-
associated antigen 4 (CTLA4), which downmodulates the amplitude of T cell activation.
Antibody blockade of CTLA4 in mouse models of cancer induced antitumour immunity.
• Clinical studies using antagonistic CTLA4 antibodies demonstrated activity in melanoma.
Despite a high frequency of immune-related toxicity, this therapy enhanced survival in
two randomized Phase III trials.
• Anti-CTLA4 therapy was the first agent to demonstrate a survival benefit in patients with
advanced melanoma and was approved by the US Food and Drug Administration (FDA) in
2010.
• Nivolumab has been approved in 2014. Pembrolizumab was also approved by the FDA in
2014.
• The first monoclonal antibody approved by the FDA for immune checkpoint blockade
was ipilimumab, approved in 2011. Ipilimuma b blocks the inhibitory immune checkpoint
CTLA-4.
Immune Checkpoint Blockade

35. Immune Checkpoint Blockade

36. Combined Therapy
• Monoclonal antibody trastuzumab targets ERBB2 in breast cancer and
expose them to ADCC which depends on NK cells.
• Ronald Levy and colleagues investigated whether activation of the co-
stimulatory molecule CD137 (also known as TNFRSF9 and 4-1BB) in NK cells
could improve trastuzumab efficacy.
• In vitro studies showed that co-incubation of ERBB2-expressing breast
cancer cell lines and purified human NK cells with trastuzumab upregulated
CD137 on the NK cells.
• These activated NK cells were able to kill trastuzumabcoated ERBB2-
expressing breast cancer cell lines through ADCC, and this was enhanced by
a CD137 agonistic antibody.

37. Combining PROSTVAC with ipilimumab
Combined Therapy

38. Combined Therapy
Combining PROSTVAC with radiotherapy

39. Cancer Gene Therapy

40. Cancer Gene Therapy
• Direct attack on tumor cells
a) Transfer of tumor suppressor gene
b) Inhibition of oncogenes
c) Suicide gene therapy
d) Oncolytic viruses (replication-competent viruses)
• Harnessing immune response to tumor antigens.
• Chemoprotection
• Anti-angiogenic therapy

41. p53 and cell arrest

42. Transcription Factor E2F

43. Wild Type and Mutant p53

44. Inhibition of oncogenes

45. Antisense Gene Therapy

46. Rhibozyme Gene Therapy

47. Suicide Gene Therapy

48. Enzyme-prodrug combination for suicide gene therapy
Enzyme Prodrug Product Mechanism
HSV-tk ganciclovir ganciclovir
triphosphate
blocks DNA synthesis
Cytosine Deaminase 5-fluorocytosine 5-fluorouracil (5-FU) blocks DNA and RNA
synthesis
Cytochrome P450 cyclophosphamide phosphoramide
mustard
DNA alkylating agent;
blocks DNA synthesis

49. Oncolytic Virus

50. Genetically modified tumor vaccines
• Immune system may play a role in controlling tumor growth and
development.
• However, antigens present on tumor cells are not sufficient to boost
immune response.
• As a result, modification of tumor cells – i.e, overexpressing certain
genes, may stimulate immune system to respond to tumor cells.

51. Strategy of genetically modified tumor vaccines
Isolate tumor cells from a patient
Transduce such cells with vector – eg. Retroviral vector
harboring cytokine gene
Inject such modified cells into patients

52. Chemoprotection

53. Anti-angiogenic gene therapy

54. References
• Cancer immunotherapy via dendritic cells, Karolina.P and Jacques.B, Focus on tumour
immunology & immunotherapy, Nature reviews, cancer vol12, April 2012,p265-277© 2012
Macmillan Publishers Limited
• Antibody therapy of cancer Andrew M. Scott1, Jedd D. Wolchok and Lloyd J. Old Nature Reviews,
April 2012, Vol 12, p278-287 © 2012 Macmillan Publishers Limited. All rights reserved.
• Cytokines in Cancer Immunotherapy, Sylvia. L and Kim.M, Cancers 2011, Vol3,3856-3893;
doi:10.3390/cancers3043856, ISSN 2072-6694.
• Vaccines in cancer: GVAX, a GM-CSF gene vaccine, Nemunaitis J, Expert Rev Vaccines. 2005
Jun;4(3):259-74
• Complete Regression of Metastatic Cervical Cancer After Treatment With Human Papillomavirus–
Targeted Tumor-Infiltrating T Cells , Sanja Stevanović et al, American Society of Clinical Oncology,
May 10, 2015 vol. 33 no. 14 1543-1550 ,doi: 10.1200/JCO.2014.58.9093
• Combinations that work, Sarah Seton-Rogers, Research Highlights Nature Reviews, Cancer Vol12,
APRIL 2012