Project description:Colorectal cancer (CRC) is the third most diagnosed type of cancer and the second leading cause of cancer death worldwide. Despite the increasing knowledge of CRC molecular biology and the development of new targeted therapies, its high heterogeneity hampers the efficacy of current treatments. Thus, there is a pressing need to identify new effective therapeutic targets and improve immune therapies for these patients. In this regard, S-nitrosoglutathione reductase (GSNOR) is a denitrosylase enzyme that has been suggested to play a tumour suppressor role, although the mechanisms responsible are still largely unclear. Therefore, the main objective of this project was to understand the role of GSNOR in CRC tumorigenesis and its therapeutic implications. Firstly, we classified CRC tumours as GSNOR-high or low according to their GSNOR expression as assessed by immunohistochemistry (IHC). Accordingly, we found that GSNOR deficiency was associated with worse prognosis factors such as a larger tumour size at diagnosis, higher TNM stage, higher grade of tumour budding (TB), the CMS4 subtype, lower expression of the intestinal differentiation markers CDX2 and AE1/AE3 cytokeratin and a worse progression free survival (PFS) and overall survival (OS). We next investigated the differences in gene expression between CRC GSNOR-high and low tumours, uncovering significant alterations in metabolism and immune system pathways. Hence, GSNOR-deficient tumours were characterized by immune suppressive features and a dysregulation of their metabolism, favouring other metabolic pathways than OXPHOS.
Project description:Immunotherapeutics represent highly promising agents with the potential to improve patient outcomes in a variety of cancer types. Unfortunately, single-agent immunotherapy has achieved limited clinical benefit to date in patients suffering from pancreatic ductal adenocarcinoma (PDAC). This may be due to the presence of a uniquely immunosuppressive tumor microenvironment (TME) present in PDACs, which creates a barrier to effective immune surveillance. Critical obstacles to immunotherapy in PDAC tumors include the dense desmoplastic stroma that acts as a barrier to T-cell infiltration and the high numbers of tumor-associated immunosuppressive cells. We have identified hyperactivated focal adhesion kinase (FAK) activity in neoplastic PDAC cells as a significant regulator of the fibrotic and immunosuppressive TME. We found that FAK activity was elevated in human PDAC tissues and correlates with high levels of fibrosis and poor CD8+ cytotoxic T-cell infiltration. Single-agent FAK inhibition (VS-4718) dramatically limited tumor progression, resulting in a doubling of survival in the p48-Cre/LSL-KrasG12D/p53Flox/+ (KPC) mouse model of human PDAC. This alteration in tumor progression was associated with dramatically reduced tumor fibrosis, decreased numbers of tumor-infiltrating immature myeloid cells and immunosuppressive macrophages. We postulated that these desirable effects of FAK inhibition on the TME might render PDAC tumors more sensitive to immunotherapy. Accordingly, we found that VS-4718 rendered the previously unresponsive KPC mouse model responsive to anti-PD1 and anti-CTLA4 antagonists leading to a nearly tripling of survival times. These data suggest that FAK inhibition increases immune surveillance by overcoming the fibrotic and immunosuppressive PDAC TME thus rendering tumors more responsive to immunotherapy. We treated KP orthotopic tumor-bearing mice with vehicle and FAK inhibitor (FAKi) for 14 days, then extracted total RNA from tumor tissues.
Project description:Currently, a marked number of clinical trials on cancer treatment have revealed the success of immunomodulatory therapies based on immune checkpoint inhibitors that activate tumor-specific T cells. However, the therapeutic efficacy of cancer immunotherapies is only restricted to a small fraction of patients. A deeper understanding of key mechanisms generating an immunosuppressive tumor microenvironment (TME) remains a major challenge for more effective antitumor immunity. There is a growing evidence that the TME supports inappropriate metabolic reprogramming that dampens T cell function, and therefore impacts the antitumor immune response and tumor progression. Notably, the immunosuppressive TME is characterized by a lack of crucial carbon sources critical for T cell function and increased inhibitory signals. Here, we summarize the basics of intrinsic and extrinsic metabolic remodeling and metabolic checkpoints underlying the competition between cancer and infiltrating immune cells for nutrients and metabolites. Intriguingly, the upregulation of tumor programmed death-L1 and cytotoxic T lymphocyte-associated antigen 4 alters the metabolic programme of T cells and drives their exhaustion. In this context, targeting both tumor and T cell metabolism can beneficially enhance or temper immunity in an inhospitable microenvironment and markedly improve the success of immunotherapies.
Project description:Cancers evade the immune system in order to grow or metastasise through the process of cancer immunoediting. While checkpoint inhibitor therapy has been effective for reactivating tumour immunity in some cancers, many solid cancers, including breast cancer, remain largely non-responsive. Understanding the way non-responsive cancers evolve to evade immunity, what resistance pathways are activated and whether this occurs at the clonal level will improve immunotherapeutic design. We tracked cancer cell clones during the immunoediting process and determined clonal transcriptional profiles that allow immune evasion in murine mammary tumour growth in response to immunotherapy with anti-PD1 and anti-CTLA4. Clonal diversity was significantly restricted by immunotherapy treatment at both the primary and metastatic sites. These findings demonstrate that immunoediting selects for pre-existing breast cancer cell populations, that immunoediting is not a static process and is ongoing during metastasis and immunotherapy treatment. Isolation of immunotherapy resistant clones revealed unique and overlapping transcriptional signatures. The overlapping gene signature was predictive of poor survival in basal-like breast cancer patient cohorts. Some of these overlapping genes have existing small molecules which can be used to potentially improve immunotherapy response.