BC Cancer – Vancouver – Page 2

The molecular dissection of aggressive B-cell lymphoma

Aggressive B-cell lymphomas are the most common form of lymphoma and ~50% of patients are cured with modern treatments. However, the outcomes for patients whose disease is not cured are dismal with ~10% of those patients alive at 5 years. This shows that these lymphomas, although grouped together on the basis of what they look like down the microscope, represent clusters of different lymphoma groups. A better understanding of the 'molecular wiring'of these lymphomas is critical to identify patients at high risk of resistant lymphoma and providing better treatments.

This project will provide a rational new way to group lymphomas based on differences in the molecular wiring. This will be acheived by performing and analysing genomic sequencing on a large number of aggressive B-cell lymphomas brought together through an international lymphoma consortium. Further, tumour samples will be analysed from the time of diagnosis and when the lymphoma relapses to see whether this molecular wiring remains stable or changes with treatment. It is anticipated that this major step forward in our knowledge will be translated into new tools for matching a patient's lymphoma to the correct treatment and improving patient outcomes.

Predictors of immunotherapy benefit in patients with microsatellite stable metastatic colorectal cancer

Introduction: Colorectal cancer (CRC) is the second most common cancer. Once metastatic, patients are generally incurable and receive treatment to prolong survival. Immunotherapies use a patient's immune system to attack their cancer. These treatments are effective in CRC patients with microsatellite instability (MSI). Unfortunately, 95% of patients lack MSI and are called microsatellite stable (MSS). This group usually doesn't respond to immunotherapy and we need to explore why.

Specific Aims:

We aim to identify:

why some MSS patients benefit from immunotherapy, and
what can we target to activate immune cells in patients who don't respond to immunotherapy.

Methods: We will investigate how the immune system and tumors interact in patients from two clinical trials. These trials evaluated immunotherapy in MSS CRC. Blood and tumor samples from these trials will be tested to identify features that predict response. These results will then guide the creation of new clinical trials with immunotherapy for CRC using our findings.

Significance: Immunotherapy does not work for the 95% of CRC patients who are MSS. We will identify how to activate the immune system in CRC patients with MSS so they too can benefit from immunotherapy.

Identification of IL1RAP as a novel oncoprotein and therapeutic target in Ewing sarcoma

Ewing Sarcoma (EWS) is an aggressive form of childhood cancer that occurs on bone and soft tissue. Although conventional cancer therapeutic strategies, such as chemotherapy, radiation and surgery, have improved survival in patients with localized EWS tumours, they are ineffective for patients with metastatic disease. In addition, conventional chemotherapy is often toxic and carcinogenic, which carries short- and long-term toxicities. In the past few years, immunotherapy has been promoted as an effective means to prolong survival or eliminate tumor cells in patients with specific cancers.

However, effective immunotherapeutic strategies for EWS have not yet been described. Identification of highly specific cell surface markers of tumor cells is critical for developing targeted immunotherapy strategies. We have identified IL1RAP (Interleukin 1 receptor accessory protein) as a cell surface protein that is highly expressed in EWS in comparison to normal tissues/organs, and that is important for tumorigenesis in this disease. In this project, we aim to develop immunotherapeutic strategies by targeting IL1RAP in human EWS, while also delineating the key mechanisms mediating the tumor-promoting function of this protein.

End of Award Update – March 2022

Most exciting outputs

During the Health Research BC / Lotte & John Hecht Memorial Foundation award period, my work in Dr. Poul Sorensen’s lab identified IL1RAP (Interleukin 1 receptor accessory protein) as a cell surface protein that is highly expressed in Ewing sarcoma, but minimally expressed in pediatric and adult normal tissues, nominating it as a promising immunotherapy target. Our mechanistic studies show that IL1RAP maintains cyst(e)ine and glutathione pools in Ewing sarcoma, which are vital for redox homeostasis and metastasis.

To therapeutically target IL1RAP, we have collaborated with Dr. Dimiter Dimitrov of the University of Pittsburgh to develop IL1RAP binders via phage-display biopanning. We identified highly specific IL1RAP binders, one of which has been engineered into a humanized IgG1 antibody. This antibody can induce antibody-dependent cellular cytotoxicity (ADCC) in Ewing sarcoma cells. Moreover, in collaboration with Dr. Rimas Orentas of the Seattle Children’s Hospital, we have developed IL1RAP CAR (chimeric antigen receptor) T cells, which can mediate potent tumor cell killing in vitro, and we are currently optimizing the IL1RAP CAR for higher in vivo efficacy in mouse models. Some of these findings have been published in Cancer Discovery.

With regard to the mechanistic studies of the pathobiological function of IL1RAP, i.e. IL1RAP maintains cyst(e)ine and glutathione pools that promote Ewing sarcoma metastasis, we recently published a review article on this topic in Trends in Cell Biology, a Cell Press journal.

Impacts so far

Based on our findings, we have filed a patent for IL1RAP CAR-T cell therapy in human cancers.

Potential future influence

Based on our findings, we may initiate clinical trials in the near future to target IL1RAP with immunotherapeutic strategies, including highly specific chimeric antigen receptor (CAR) T cells and antibody-drug conjugates.

Next steps

We aim to develop various immunotherapeutic strategies to target IL1RAP in human cancers, including highly specific chimeric antigen receptor (CAR) T cells and antibody-drug conjugates.

Useful links

Defining mechanisms of lineage transformation in lung cancer to combat resistance to targeted therapies

Lung cancer is the leading cause of cancer-related death in Canada. A major reason for the poor prognosis is the lack of effective drugs for treating advanced tumours.

New understanding of the mutations driving lung cancer has led to the development of targeted therapies that selectively inhibit mutated genes, leading to rapid cancer regression in specific subsets of patients. However, while these therapies improve patient survival and quality of life, they are not curative as all patients develop drug resistance.

While some causes behind this resistance have been defined, others remain elusive, and are becoming more prominent with newer generations of drugs. A major example is tumours changing how they look—shifting from one type of lung cancer to another—but what causes this is still not clear.

Dr. Inoue’s research will test whether treatment with targeted therapies creates the environment that allows tumours to “change their skin” and continue to grow in the presence of drugs. The goal is to determine the genes involved in this shift and prove they are responsible for drug resistance. This will lead to new therapeutic strategies that will provide longer-term survival benefits for lung cancer patients.