RIPK3 and MLKL expression in rectal cancer cells and their sensitivity to canonical and alternative Necroptotic pathways

• Grant number: 16/19110-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2017
• End date: February 28, 2019
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Ricardo Weinlich
• Grantee: Guilherme Afonso Vergara
• Host Institution: Instituto Israelita de Ensino e Pesquisa Albert Einstein (IIEPAE). Sociedade Beneficente Israelita Brasileira Albert Einstein (SBIBAE). São Paulo , SP, Brazil

Abstract

Necroptosis is a cell death pathway characterized by plasma membrane rupture and cytoplasmic content leakage, leading to a pro-inflammatory environment. Membrane disruption is mediated by MLKL when activated by RIPK3 phosphorylation. RIPK3, in turn, can be activated by a wide variety of stimuli, including but not limited to Death and Toll-like receptors, viral sensors, DNA damage and chemotherapeutic agents. Alterations in RIPK3 expression levels have been reported in several pathophysiological conditions, impacting on the sensitivity to necroptosis. Amongst these conditions, some types of cancer, such as breast, colon and lung cancer and acute myeloid leukemia present very low levels of RIPK3 expression, if not absent. Furthermore, under average RIPK3 expression levels indicate a higher probability of metastatic recurrence in breast cancer patients. Amongst cancer types, rectal cancer is one of the most prevalent and it is highly lethal. Yet, there is no study that explores the relevance of this pathway during tumor transformation, progression, and resistance. To date, the most effective treatment against rectal cancer combines radiotherapy with at least two chemotherapeutic agents, one being 5-Fluorouracil, which is capable of inducing necroptosis. However, the lack of predictive response markers for this type of treatment hampers its use in a wider and more standardized manner. Therefore, we propose to characterize the expression levels of both RIPK3 and MLKL in rectal cancer cells, correlating them with clinical outcomes and cancer responsivity to current treatments. Moreover, we will explore means to induce RIPK3 and MLKL expression to sensitize these cells to necroptosis by classical initiators as well to activate MLKL independently of RIPK3. (AU)