The impact of CLnAs on cancer cells using the zebrafish model

Details

Supervisors

Debier, Cathy ; Larondelle, Yvan

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en chimie et bioindustries, à finalité spécialisée

Abstract

Cancer is a leading cause of death worldwide. Almost 10 million people died of cancer in 2020. In Belgium, one third of men and one quarter of women will be diagnosed with cancer before the age of 75. Cancer is characterized by excessive and poorly regulated cell proliferation. Cancer can spread and invade surrounding tissues or even move to another part of the body to form metastases that are the main cause of cancer death. To support the fast growth and counter the challenging conditions found in tumors, cells need to enhance the rate of metabolic reactions, and alter their metabolism. The ability of cancer cells to escape from the apoptotic cell process and their progressive resistance to chemotherapeutic agents calls for innovative strategies involving alternative cell death pathways. In that respect, ferroptosis appears as a promising candidate. It has indeed been shown that the accumulation of polyunsaturated fatty acids, and particularly conjugated linolenic acids (CLnAs), within cell membranes can lead to lipid peroxidation, and subsequent ferroptosis. The cytotoxic effect of four CLnA isomers was studied in vitro on two different subclones of zebrafish melanoma cell line (ZMEL1). Viability tests show that CLnAs are cytotoxic to both ZMEL1 subclones, in a dose dependent manner, with a significant difference between the different isomers, jacaric acid being the most toxic. In addition, the two ZMEL1 subclones show significant differences in their sensitivity towards the CLnA isomers. To investigate the difference in sensitivity between the two ZMEL1 subclones, the expression level of two genes involved in ferroptosis, ACSL4 and GPX4, were studied using RT-qPCR and western blot analyses. Each of these genes has two forms in zebrafish. Our findings highlight that both ZMEL1 subclones express the genes of interest. The CLnA isomers appear to exert an influence on both transcript and protein levels. However, to establish a more conclusive outcome, it is imperative to replicate these experiments to further validate the results. Although the in vitro model provides an initial insight into the potential cytotoxic effect of CLnAs on cancer cells, it highlights new questions about the interactions of CLnAs with several compounds in a more complex environment such as in the tumor microenvironment in vivo. Accordingly, the in vitro findings ought to be evaluated using appropriate in vivo models. If the cytotoxic effect of CLnA isomers is confirmed in vivo, dietary supplements of CLnAs as adjunctive therapy alongside existing anti-cancer treatments could be promising to improve the likelihood of achieving complete remission in patients.