Our motivation behind participating in iGEM is using our interdisciplinary knowledge to work on a project that would make a significant difference in the real world, starting with our local communities. One such problem that plagues our country, India, is Lung cancer. Lung cancer is one of the leading causes of cancer death in India, accounting for 8.1% of all cancer-related deaths, making it the third leading cause of cancer-related mortality after breast, lip, and oral cavity cancers. NSCLC makes up 82% of all lung cancers, and in 83.4% of the cases it is too late to save the patient's life due to advanced disease stages IIIB and IV¹. Treatment for non-small cell lung cancer (NSCLC) can be difficult for a number of reasons, including the disease's advanced stage, the tumor's unique genetic properties, and the patient's general condition.

Now, how is this an enhanced problem in India? India recently surpassed China to become the most populated country in the world. In such a densely populated country, cities are highly polluted, making a large portion of the population vulnerable to its harmful effects. The impact is greater on the poorer class of factory workers, who are more exposed to lung disorders in general due to exposure to pollutants and chemicals. Another affected group are households below the poverty line, as they cannot afford expensive LPG, and are forced to resort to burning wood or coal for cooking. A study found predominant coal users in Asia had an increased risk of lung cancer among men, women, and ever-smokers2 ²

EEven the highly effective CAR-T cell therapy is not effective in this case. The treatment is highly dependent upon receptor specificity and so is rendered ineffective by solid tumors due to the presence of a multiple-antigen system, due to which receptor targeting fails. CAR T cells are also not able to penetrate into the cancer cell mass as it is too dense³. We were inspired by the work on CAR T cells byFreiburg University in 2017 as well as Team AFCM-Egypt in 2019, and decided to combat the issue of solid tumor effectiveness of CAR T cell therapy, with a primary study on NSCLC.

An effective solution to tackle lung cancer is CAR (Chimeric Antigen Receptor) T cell therapy, with a remission rate of 90.9% (when compared to 37.9% for common therapies like chemotherapy and radiotherapy) in acute lymphoblastic leukemia. ³

A Background to CAR T cell therapy

• T-cells are collected from the patient and then modified in a laboratory to express a protein called a chimeric antigen receptor (CAR) on their surface allowing them to recognize and bind to specific molecules on the surface of cancer cells, which enables them to kill the cancer cells.
• The modified T-cells are then infused back into the patient, where they can help to control or eliminate the cancer.
• CAR T cells are a combination of an Antigen recognizing domain and Signaling domains that are present in T cell receptors. As advancements are made in CAR T cell development, more signaling domains are added and these are termed as different generations of CAR T.
• CAR T cells work by first binding to the cancer specific antigen through the CAR receptor, after which the usual T cell response is initiated specifically at the tumor cell.

Figure 1: Structure of CAR T cell

Figure 2: Different Generations of CAR T cells⁵
Figure 3: CAR T cell therapy at a glance Credit: NIH-NCI, open source image

To date, the US Food and Drug Administration (FDA) has approved six CAR-T cell therapies indicated for hematological cancers, such as B-cell lymphoblastic leukemia and B-cell non-Hodgkin lymphomas⁶. However, treatment against variants of solid tumors hasn’t shown to be effective.

But why?

• This is primarily because solid tumors are adhered together, and CAR T cells cannot penetrate through. A key gene involved in this adherence is the STAT3 gene⁷
• Another difference between solid tumors and hematological cancers is solid tumors display antigen heterogeneity between tumor types and patients with the same cancer
• Our hypothesis involves designing a modified CAR T-cell treatment, which utilizes an additional step that breaks the cancer into smaller parts, as well as a plant based bioactive that has been proved to have anti - cancer activity

But how?

Our idea involves editing the cell surface of a T cell to express Cannabinoid receptor 1, to which our choice of drug, Honokiol binds to. Honokiol is a plant bioactive compound derived from the bark of the magnolia species. Various studies have proven that honokiol exerts broad-range anticancer activity in vitro and in vivo by regulating numerous signaling pathways, one of them being the STAT3 signaling pathway⁸. STAT3 is a well-known oncogene and its phosphorylated form leads to enhanced cell proliferation, invasion, and survival for many cancer types⁹. STAT3 also is responsible for increasing cell adhesion molecules¹⁰

Honokiol is responsible for reducing the expression of STAT3 as well as its phosphorylated form, thus inhibiting adhesions between the tumor cells and showing cytotoxic activity towards them.

Honokiol undocks from the Cannabinoid receptor 1 at the tumor site with the help of an antagonist to the receptor, a small molecule, AM6538 ¹¹. Once the drug acts on the tumor mass, the tumor mass essentially becomes more pliable for the CAR T cells to act.

Since the proposed treatment itself takes advantage of the cellular property of cell adhesion, it can work not only for lung cancer, but also help with the treatment of other solid tumors. Moreover, a cellular vector is used to deliver the main drug in order to prevent potential side effects and increase specificity. This project seeks to develop this line of treatment with the lens of CAR-T, whilst also unlocking new avenues for cancer treatment.

Therefore, the project is driven to solve a standing therapeutic problem, enhance existing therapy, aid vulnerable social groups and initiate application of a nascent tool in cancer.

By introducing CAR-T therapy for lung cancer, we offer local communities a cutting-edge treatment modality with the potential to substantially improve patient outcomes. Thus, increasing survival rates, and improving the quality of life for lung cancer patients in our community. Our idea can contribute to the broader field of oncology by stretching the boundaries of CAR-T therapy in lung cancer, paving the way for future advances in CAR-T therapy for other forms of solid tumors. Possibly resulting in a global paradigm shift in cancer treatment. Successful implementation of CAR-T therapy for lung cancer in our local community can have a broader impact on healthcare policies and guidelines. In conclusion, our concept of utilizing CAR-T therapy to treat lung cancer has the potential to enhance treatment options, expand access to advanced therapies, contribute to the global knowledge base, influence healthcare policies, and raise awareness. We aim to foster innovation in order to grow.