Background and Rationale
In 2018, 509,590 new cases and 248,724 deaths were attributed to B cell lymphoma worldwide. (1) B cell lymphoma is cancer of the B lymphocytes/B cells which make up a crucial part of our immune system. Lymphoma compromises these cells, along with our ability to produce antibodies in response to invading pathogens. This can manifest as fevers, night sweats, and swelling of the lymph nodes among other uncomfortable and possibly fatal symptoms.
Current treatments used against B cell lymphoma include CHOP, radiation therapy and CAR-T cell therapy. CHOP is a form of chemotherapy with up to 60-70% progression-free complete remission. (2) This treatment however is nonspecific to the cancer, and can be accompanied by many prevalent side effects including altered taste perception, hair loss, extreme fatigue, nausea, difficulty sleeping, constipation among many others. (3) Radiation therapy, more commonly used for treatment in early stage lymphoma, places patients at risk of experiencing similar side effects. Alternatively, CAR-T is a targeted immunotherapy which genetically modifies the patient’s own T-cells to recognize and attack cancer in the body. Unlike systematic treatments, CAR-T does not have the same severity of side effects and has a cure rate of 40% in B cell lymphoma patients. (4) CAR-T however is very expensive, making this treatment inaccessible to many patients.
High prevalence of B cell lymphoma as well as limitations to current therapies has inspired us to develop a novel AAVP-based gene therapy treatment.
Adeno-associated virus phage (AAVP) is a viral vector made by combining a bacteriophage with parts of an adeno-associated virus (AAV). Bacteriophages are viruses that only infect bacteria, while the AAV is able to infect mammalian cells only under certain conditions. This combination makes the AAVP able to infect human cells, while avoiding a large-scale, undesirable immune response from the body. This vector is also highly modular, meaning there are many areas that can be easily genetically modified to better adapt to different tasks.
Project Description
Our AAVP vector is made from the scaffolding of the f3-55nm filamentous bacteriophage. To this filamentous phage, we have inserted an expression cassette flanked by AAV inverted terminal repeats (ITRs). The expression cassette codes for tumor necrosis factor alpha (TNF-α) and granzyme B (GrzB) which induce cancer cell death. Importantly, the AAV ITRs are present to ensure this expression cassette is compatible with human cancer cells.
In order for this AAVP vector to selectively infect cancerous B cells, anti-CD22 single-chain fragment variables (scFvs) are displayed on the AAVP’s structure. The anti-CD22 scFv is able to bind specifically to CD22 receptors that are primarily on the surface of cancerous B cells. Once bound, the AAVP vector is able to enter the B cell.
In theory, our AAVP vector will be administered into the body where it can seek out cancerous B cells. When in the presence of the CD22 receptor found on these cancerous cells, the anti-CD22 scFv of the AAVP vector will bind and allow entry of the viral phage. Our AAVP will then utilize the cancerous B cell’s machinery to express TNF-α and GrzB, killing the cancer cell.
Human Practices
Beyond the scope of the lab, factors concerning ethical, socio economic, biosafety, and biosecurity were thoughtfully engaged with. At the heart of onCAP are the lives of cancer patients along with the stories they have to tell. In light of this, we conducted interviews from 5 unique interviewees to educate the public on barriers in healthcare such as medical racism, survivorship and self-advocacy during diagnostic screenings and routine checkups. These interviews were 15 minutes each and were shared on the McMaster SynBio Instagram account.
On the note of education, our team held two webinars with health experts, Dr. Alexander Hynes and Dr. Gelarah Zadeh. Dr. Alexander Hynes discussed the relationship of bacteriophages and the gut microbiome using his own research. Dr. Gelarah Zadeh discussed her research on the blood brain barrier to target brain tumours and targeting several pathways in cancer therapies.
Additionally, we collaborated with the Leukemia & Lymphoma Society of Canada (LLSC). Through this collaboration, onCAP was outlined in a one page infographic and reached an audience of 20,000-30,000 individuals. Many of these individuals were cancer patients. Hence, this collaboration bridged the gap on information regarding the use of phages to target B cell lymphoma while being able to understand the patient experience of those undergoing cancer therapies for B cell lymphoma and other various forms of cancer.
Our team published an article in the Hamilton Spectator discussing the importance of caregivers such as doctors, nurses, pharmacists, and family as means to impact the lives of cancer patients through their social interactions, daily lives and finances of treatment costs. From the responsibilities of caregivers, to physical, emotional and financial challenges they face, to financial obstacles, see the article published on the Hamilton Spectator to delve into an in depth view. Following this, a second article of ours was published on the Hamilton Spectator discussing the discrepancies in healthcare accessibility between the U.S. and Canadian healthcare systems. For more information check out the article on the Hamilton Spectator! These publications led to a multiplicity of connections with local non-profit organizations.
References
1. Sun H, Xue L, Guo Y, Du J, Nan K, Li M. Global, regional and national burden of non-Hodgkin lymphoma from 1990 to 2017: estimates from global burden of disease study in 2017. Ann Med. 54(1):633–45.
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2. Jakobsen LH, Øvlisen AK, Severinsen MT, Bæch J, Kragholm KH, Glimelius I, et al. Patients in complete remission after R-CHOP(-like) therapy for diffuse large B-cell lymphoma have limited excess use of health care services in Denmark. Blood Cancer J. 2022 Jan 27;12(1):16.
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3. Sitzia J, North C, Stanley J, Winterberg N. Side effects of CHOP in the treatment of non-hodgkin’s lymphoma. Cancer Nurs. 1997 Dec;20(6):430–9.
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4. Vitale C, Strati P. CAR T-Cell Therapy for B-Cell non-Hodgkin Lymphoma and Chronic Lymphocytic Leukemia: Clinical Trials and Real-World Experiences. Front Oncol [Internet]. 2020;10. Available from: https://www.frontiersin.org/articles/10.3389/fonc.2020.00849