IMI9: Cancer Immunotherapy Flashcards
1
Q
What is immunotherapy?
A
a unique approach aimed at defeating cancer. It is designed to instruct the body’s own immune system to kill off the patient’s own cancer cells in the same way it does with other foreign invaders, such as bacteria
2
Q
Chronic damage to melanocytes (pigment producing cells in skin) by UV radiation leads to what?
A
Leads to most cases of melonoma
3
Q
Can melonoma’s spread?
A
yes e.g. lungs and liver
4
Q
What’s immunoediting?
A
The cells the immune system can’t sense survive and replicate and so the tumour can evade the immune system
5
Q
What can PDL1 do?
A
Expressed by tumour cells
Inhibitor molecule
Binds to the PD1 receptor on T-cells - inactivating them: this is an immune checkpoint
6
Q
Tumour cells can attract regulatory T cells and macrophages to do what?
A
Suppress the activity of other immune cells; thereby supporting tumour growth
7
Q
What is adoptive cell therapy?
A
T-cells extracted from patients, tested for their ability to kill cancer cells, replicated and infused back into patients
8
Q
A therapy where antibodies bind to PD1 receptor does what?
A
Stops T-cells from switching off
9
Q
How can you boost the activity of anti-tumour immune cells?
A
Treating patients with cytokines: interleukin 2 and interferon alpha
10
Q
Another immune checkpoint that can be targeted is what?
A
CTLA4: blocking this molecule allows DC to drive anti-tumour cell responses
11
Q
What does it mean by immune therapy being specific?
A
- Immunotherapy should recognise specific tumour antigens expressed by cancer cells
- The first key step is identifying a tumour antigen that is found primarily on cancer cells and typically not on normal cells
12
Q
What does it mean by immune therapy being adaptable?
A
- Immunotherapy should reinforce the immune system to adapt its attack strategy over time.
- Tumour cells mutate over time, which may make them resistant to traditional anticancer therapies
- When tumour cells are killed, immune cells are exposed to tumour antigens (including the ones that have mutated), which expands and adapts the immune response cascade
13
Q
What does it mean by immune therapy being durable?
A
Immunotherapy should lead to a prolonged antitumor response because it should stimulate immunologic memory
14
Q
What two categories can cancer immunotherapies be listed into?
A
Active or passive or a combination of the two
15
Q
What does active immunotherapy mean?
A
Aims to trigger an anti-tumour response from the immune system of the patient (e.g. vaccination)
16
Q
What does passive immunotherapy mean?
A
Requires the use of biological reagents such as mAbs or antigen-specific adaptive immune cells
17
Q
What does active immunotherapy include?
A
- Cytokine therapy: stimulation of the patient’s immune system with cytokines;
- Cancer vaccines: stimulation of the patient’s immune system with vaccines.
18
Q
What does passive immunotherapy include?
A
- Monoclonal Antibody therapy: therapeutic antibodies are provided to the patient
- Cell-based therapy: immune cells or genetically modified immune cells are provided to the patient
19
Q
What are interferons?
A
Interferons (IFNs) are known for their antiviral activity but they also play other key roles in regulating immune activity. They can be divided into three groups
20
Q
What are the three groups IFNs can be grouped into?
A
- Type I (these include 13 IFN-α subtypes and IFN-β)
- Type II (IFN-γ)
- Type III (IFN-λ subtypes)
21
Q
What is the only IFN approved for the treatment of cancer? What does it do?
A
Interferon alpha. It can promote B cell proliferation, as well as activate natural killer (NK) cells
22
Q
What are interleukins?
A
Interleukins work as intercellular signals between leukocytes, our white blood cells
23
Q
What was the first immunotherapeutic agent to treat cancer in humans?
A
Interleukin-2 (IL-2). It stimulates T cell growth and proliferation, and is largely produced by CD4+ T cells
24
Q
What are chemokines? What do they do?
A
Chemokines induce movement of surrounding cells through a process called chemotaxis. They actually have a double-edged role in tumour formation:
they can either decrease tumour growth by recruiting leukocytes to the tumour site, or
they can stimulate tumour growth by influencing movement of cancer cells
25
By altering the cytokine milieu at the tumour site using cytokines such as IL-2 or IL-12 what happens?
You can potentially convert an immunosuppressive microenvironment to one that promotes and enhances an immune response
26
What are the side effects of cytokine therapy?
Flu-like symptoms
Depression
Fatigue
Some of them can even be unpredictable since cytokine biology is interpreted using mouse models which are not all that similar to the humans despite the many extrapolations done in research setups over the years
27
What is the half-life of cytokines like?
Short half-life: even if cytokines are tremendously potent, they do have short half-lives. Therefore, to maintain the required blood concentration for biological activity, cancer patients must receive a large amount of the cytokine preparation
28
Why is there an issue with the amount of cytokine produced for treatment?
Expressing sufficient amounts of cytokines in the appropriate target cells is still an issue and cytokine gene therapy has been explored as a possible approach
29
The delivery of IL-12 was obtained using what methods?
- Direct infusion of the recombinant protein
- gene therapy using viral and non-viral vectors
- electroporation
- IL-12-containing microspheres
- nanoparticles
- the transfer of IL-12-overexpressing stromal and immune cell types
30
What is adjunct therapy
An additional therapy that is used with the primary therapy, with the objective of enhancing the primary therapy. It can also be referred to as adjunctive therapy.
31
What are the three cytokines approved by the FDA?
IL-2
IFN-a2a
IFN-a2b
32
How do IL-2s act?
Targets cells of the adaptive immune system, such as T cells and B cells, to respond to tumours
33
How do IFN-as act?
They stimulates the generation of innate immune cells, such as dendritic cells (DCs) and macrophages to help the fight against cancer
34
What has IL-2 been approved for?
Treatment of some forms of metastatic melanoma and renal cell carcinoma (RCC)
35
What has IFN-a2a been licensed for the treatment of?
Hairy cell lymphoma and Philadelphia chromosome-positive [Ph+, t(9;22)] chronic myelogenous leukaemia (CML)
36
What has IFN-a2b been licensed for the treatment of?
Hairy cell leukaemia, AIDS-related Kaposi's sarcoma, follicular lymphoma, melanoma, multiple myeloma, genital warts (Condyloma acuminata) and cervical intraepithelial neoplasms.
37
What is the concept behind cancer vaccines?
They are designed to activate cells of the immune system to recognise and act against specific antigen(s) on the tumour cell.
38
What are the four different types of cancer vaccines?
Antigen vaccines
Dendritic cell vaccines
DNA/RNA vaccines
Tumour cell vaccines
39
Would you use a vaccine before or after a patient develops the tumour?
It depends on what you are trying to achieve:
- If you want to protect a patient before s/he develops the tumour than you will need a prophylactic vaccine
- If you want to help the immune system of the patient after s/he has received a cancer diagnosis, then you will need a therapeutic vaccine
40
What are prophylactic vaccines?
Prophylactic or preventative vaccines provide prior immunity so that the body can build up antibodies without contracting the illness.
41
When are prophylactic vaccines administered?
They are administrated to people with elevated risk of developing cancers and that may. or may not. have been diagnosed with premalignant changes in tissues.
42
Give an example of a prophylactic vaccine
An example of this would be the cervical cancer caused by the human papilloma virus (HPV).
43
What is the mechanism of a prophylactic vaccine?
If the tumour starts to grow, specific memory cells will be reactivated by the tumour antigen reaching lymph nodes.
44
When are therapeutic cancer vaccines administered?
after a tumour diagnosis and the tumour is already effectively, potentially, interacting with immune system. Most commonly, they are used in patients in remission to prevent a likely relapse and the cancer from returning.
45
What are the two types of therapeutic vaccines?
autologous vaccines
| allogenic vaccines
46
Describe what autologous cancer vaccines are
They are vaccines made from an individual’s own cancer cells and, therefore, can defined effectively as personalised vaccines.
47
Describe what allogenic cancer vaccines are
They are made from cancer cells taken from a different individual and then grown in the laboratory before being introduced into the cancer patient undergoing the treatment.
48
Describe how autologous cancer vaccines are made
1) Cancer cells are removed from patient
2) Irradiation of cancer cells
3) Genetic modification of cancer cells
4) Patient receives modified cancer
5) Enhanced immune response
49
What are the two types of prophylactic vaccines approved by the FDA?
- HPV vaccine
- Hepatitis B vaccine
- Sipuleucel-t (autologous)
50
What is the HPV vaccine for?
This vaccine protects against the human papillomavirus (HPV). Long-lasting infection with HPV can cause the development of some types of cancer
51
HPV vaccines approved by the FDA are for the prevention of?
cervical, vaginal, and vulvar cancer
anal cancer
genital warts
52
What is the Hepatitis B vaccine for?
prevents hepatitis B virus (HBV) infection. Long-lasting infection with HBV can cause cirrhosis and the development of liver cancer.
53
Who is Hepatitis B vaccines given to?
Since the 1980s, it is part of babies’ vaccination schedules in the UK, who receive it at 8, 12 and 16 weeks old. It is also given to individuals deemed at risk (drug users, multiple sexual partners, infants of infected mothers, individuals with kidney problems, etc).
54
Discuss Sipuleucel-t (Provenge®) vaccine
It is an autologous immune cell prostate cancer vaccine. Unlike the previously described cancer vaccines, this vaccine stimulates the immune system to help it fight prostate cancer cells. Clinical trials have shown to extend life for men with treatment-resistant metastatic prostate cancer.
55
What are monoclonal antibodies?
Designed against antigens presented on the surface of tumour cells
56
What are the distinct types of monoclonal antibodies (mAbs for short) used in cancer treatment? Briefly explain them.
- Naked mAbs, which can trigger, for instance, antibody-dependent cell-mediated cytotoxicity (ADCC), or simply block cancer growth factor receptors
- Conjugated mAbs with, for example, a toxin, a chemotherapeutic agent or a radioisotope
- Bispecific mAbs : designed as an antibody that is composed of two different mAbs, and can thus bind two different proteins (antigens) simultaneously
57
Why are 'naked mAbs' named this way?
Because they are not attached to any radioactive material or drug. They work on their own. They are the most common type of mAbs used as a therapy to treat and manage cancer.
58
What are the two ways mAbs can work?
1) They can improve the immune response against cancer cells by attaching to the tumour cells and marking them for the immune system to kill them through a process called ADCC. Just like when the complement is activated, ADCC also leads to cell lysis but the main difference is that, in the latter case, an effector immune cell such as a NK cells, oesinophils, macrophages or neutrophils need to be engaged to effect the destruction. Due to the dependency on the antibody for the killing, ADCC is part of the adaptive immune system.
2) They can increase the immune response by targeting immune checkpoints such as anti PD-1/anti PD-L1. Immune checkpoint inhibitors work by targeting and blocking the fail-safe mechanisms put in place to ensure that immune responses only occur when needed and that they are switched off as soon as the issue has been resolved (be it an infection, or injury). In other words, just like in the cell cycle, where you have mitogens and cell cycle checkpoints, in the immune system you also have triggers and dampening mechanisms that control the responses.
3) They can work by blocking antigens (the bits recognised by the antibodies) on cancer cells, or on other nearby cells, necessary for the cancer cells to growth or spread.
59
Explain the working of negative regulation (how cancer cells evade cell death by reducing effect of immune system on tumour cells (hiding from T-cells - tumour escape)) that occurs at the transcriptional level
- Signal transducer and activator of transcription 3 (STAT3) is a well know transcription factor downstream of IFNs and other cytokines that not only controls important processes in the immune response but also plays an important role in cancer development and progression.
- STAT3 is activated when specific cytokines bind to their cytokine receptors and it induces the transcription of genes well known for their roles in cell cycle progression, apoptosis, angiogenesis, metastasis and negative regulation of immune responses (including DC function). Upon activation, STAT3 can bind the promoter of PD-L1, which induces its upregulation in many cancer cells thereby facilitating the tumour escape. It can also activate molecules such as DNA methyltransferase 1 (DNMT1), which are well known for post-translationally modifying the promoter region of some MHC genes and thus ablating the corresponding protein expression.
60
Why are 'conjugated mAbs' named this way?
Because they are attached to a radioactive particle or to a chemotherapy drug. They are thus used as a shuttle to deliver these substances directly to the cancer cells.
61
What re the two types of conjugated mAbs?
- Radio-labelled antibodies
| - chemo-labelled antibodies
62
What are radio-labelled antibodies (conjugated mAbs)?
mAbs attached to small radioactive particles
63
Give an example of a radio-labelled mAb, how it works and what it's used to treat
For instance, to treat some types of non-Hodgkin lymphoma, an anti-CD20 antibody is used to deliver radioactivity directly to cancerous B cells. CD20 expression is restricted to B cells and it is thought that it can oligomerise on the membrane and form channels for Ca2+. This is why this molecule is believed to play a role in B cell activation, thus making it a good vehicle to be used to deliver radioactivity to these type of cancer cells.
64
What are chemo-labelled antibodies (conjugated mAbs)?
mAbs attached to chemotherapeutic drugs: these drugs are often too strong to be delivered alone and could have dangerous side effects if not attached to an antibody
65
Give an example of a chemo-labelled mAb, how it works, and what it's used to treat
Hodgkin lymphoma can be treated by delivering monomethyl auristatin E (MMAE) to cancerous cells, using an anti-CD30 antibody as a shuttle. CD-30 expression is restricted to activated T, B and NK cells, as well as monocytes, and it is involved in the proliferation of B and T cells, which is why it can be used as a vehicle in this case
66
Why are 'bispecific mAbs' named this way?
Because they are designed as an antibody that is composed of two different mAbs, and can thus bind two different proteins (antigens) simultaneously
67
How do bispecific mAbs work?
They can bring together, or cluster, the cancer cells and immune cells, which then facilitates the immune system to attack the cancer cells.
68
List the drawbacks of monoclonal antibody therapy
- Allergic reactions
- Production costs
- Tissue penetration
- Mode of action
69
Explain the monoclonal antibody therapy drawback: Allergic reactions
Such as hives or itching. Since antibodies themselves are proteins, they can sometimes stimulate allergic reactions once injected into the patient.
70
Explain the monoclonal antibody therapy drawback: Production costs
They are very expensive and a huge effort is required to produce them.
71
Explain the monoclonal antibody therapy drawback: Tissue penetration
Typically, no more than 20% of the mAbs directed against tumour-specific antigens will interact with the tumour, in murine xenograft models (i.e mouse models transplanted with human cancer cells). Most of the mAb molecules appear to remain in the blood instead.
72
Explain the monoclonal antibody therapy drawback:
| Mode of action
mAbs show diverse modes of actions in vitro, but what happens once injected in patients is not always clear.
73
Give examples of two mAbs and what they're used for
1) Trastuzumab: Herceptin: HER2 is the target, HER2+ve
| 2) Bevacizumab: Avastin: VEGF-A is the target, Metastatic CRC
74
Because of the development of two techniques, human monoclonal antibodies can now be generated without the need to immunise humans, what are these techniques?
- transgenic animals (typically mice or rats)
| - antibody phage display
75
What are transgenic animals?
| How is this harnessed for development of cancer vaccines?
genetically modified in a way that their own immunoglobulin genes are replaced with the human ones: upon immunisation they produce human antibodies based on the new inserted human gene sequences
76
How does antibody phage display generate human antibodies without immunisation at all?
This technology is derived directly from human RNA molecules and the entire process is performed in vitro.
77
Where are humanised and chimeric antibodies are derived from?
Non-human immunoglobulins (typically generated in mouse or rat) instead
78
How are humanised and chimeric antibodies made?
Using genetic engineering to make them similar to the homologous human ones. Specifically, chimeric antibodies are produced when the mouse constant domains (Fc) are replaced with that from human; humanised antibodies are instead completely similar to the human variant, despite the non-human origin of some of its complementarity determining regions (CDR)
79
What are examples of cell-based therapies?
- Tumour infiltrating lymphocytes (TILs) with IL-2
| - Genetically modified T cells (TCR or CAR-T)
80
What happens in adoptive T cell transfer (ATC) therapy?
(Tumour infiltrating lymphocytes) TILs are isolated from tumours and expanded ex vivo (i.e. outside the patient) with a high dose of IL-2, a well-known ‘growth factor’ for T cells (remember, IL-2 is not classified as a growth factor but rather as a cytokine).
81
Explain why TIL cell lines that show best tumour reactivity are then selected and further expanded to be infused back into the patient
Not all TILs will be the same or show the same killing efficiency and thus different cell lines are grown
82
Why are patients subjected to a preliminary chemotherapy regimen before the re-inoculation of the selected TILs?
There are always the endogenous lymphocytes which, if not removed (killed), could compete for growth factors and decrease the anti-tumour effects of these TILs
83
What are two classes of genetically enhanced T cell therapies?
- Chimeric antigen receptor (CAR) therapies
| - Genetically modified T cell receptor (TCR) therapies
84
Chimeric antigen receptor therapies utilise receptors that have had what happen to them?
That have been engineered to give T cells the new ability to target a specific tumour protein independently of the HLA presentation.
85
Very basically, how do chimeric antigen receptor (CAR) or TCR therapies work?
T cells are harvested from patients, genetically modified, and then the resulting CAR-T cells are reinfused into patients to fight their tumours.
86
Where are CAR-T cells derived from?
The same patient’s T cells (autologous) or from another healthy donor (allogenic), and the receptors are called chimeric because they are a mixture of various proteins
87
In more details, how do chimeric antigen receptor (CAR-T) or TCR therapies work?
Genetically modified TCR or CAR-T therapies are based on modifying the expression of specific TCR α and β chains, which mediate the recognition of the cancer antigen. This means that the tumour-specific TCR α and β chains must be first identified, then genetically engineered to improve specificity and affinity for tumour antigen and, finally, transduced into T cells to become tumour antigen-specific T cells. In both cases, T cells can be removed from a patient, genetically modified and put back into the patient where they can attack the cancer cells.
88
What is the difference in what CAR-T and TCR therapies recognise in patients?
- CAR therapies directly recognise the tumour antigen on the cell surface (external antigens) - can only attack proteins on cell membrane
- TCR therapies recognise cancer peptides presented on HLA molecules (internal antigens) - can potentially recognise the whole proteome
Thus TCRs have a bigger advantage over CARs in terms of possible targets.
89
What is presented on HLA molecules?
All the proteins expressed by a cell are degraded and loaded onto an HLA molecule to be presented
90
Why are TCRs difficult to manipulate?
Since they are composed of an α and a β chain, and on top of that require a battery of signalling proteins, which are needed to recruit the components of an immune synapse.
91
What is an immune synapse?
The interface between a lymphocyte (T/B cells or NK cells) and an APC. More specifically, it is the dynamic interaction between the membrane molecules responsible for the activation of the lymphocytes and the membrane proteins presenting the non-self antigens.
92
Name the drawbacks of cell-based therapy
- Side effects
- Manufacturing process
- In vivo efficacy
- Infusion pathway
- Antigen loss
- Hostile tumour microenvironment
93
Name the two CAR-T cell therapies have thus far received FDA approval:
1) Tisagenlecleucel (Kymriah®) for the treatment of diffuse large B cell lymphoma and B cell acute lymphoblastic leukaemia (ALL);
2) Axicabtagene ciloleucel (Yescarta®), for the treatment of relapsed/refractory large B cell lymphoma in adult patients.
94
Name the two CAR-T cell therapies have thus far received FDA approval:
1) Tisagenlecleucel (Kymriah®) for the treatment of diffuse large B cell lymphoma and B cell acute lymphoblastic leukaemia (ALL);
2) Axicabtagene ciloleucel (Yescarta®), for the treatment of relapsed/refractory large B cell lymphoma in adult patients.
95
What is LN-144?
an adoptive cell therapy designed to use TIL technology, for the treatment of patients with advanced melanoma, that the FDA granted fast track for
96
Where has adoptive T cell therapy shown to be effective in during clinical trials? (types of cancers)
treatment of leukaemia, neuroblastoma, lymphoma, metastatic melanoma and synovial cell sarcoma
97
What are the two types of active immunotherapy and what are the two types of passive immunotherapy?
Active: Cancer vaccines, cytokine therapy
Passive: Cell-based therapy, monoclonal antibodies
98
Which immune cells are normally used in cancer vaccine therapy?
Dendritic
99
Specifically, what part of the immune system does immunotherapy primarily use?
T lymphocytes
100
Which cytokines are used to expand TILs in vitro?
IL-2
101
Which of the following cell-based therapy is directed against cancer antigens that are NOT expressed on the cell surface?
TCR
102
Which immunotherapy is it used to target immune checkpoints?
naked mAbs
103
When was the first cellular immunotherapy for cancer approved?
2010
104
Which cytokines are commonly used in cytokine therapy?
IL-2 and IFN-a
105
HPV vaccine has been approved by the FDA as a:
Prophylactic vaccine
106
Which monoclonal antibody therapy induces antibody-dependent cell-mediated cytotoxicity?
Naked mAb
