Use of ascites fluid from patients to evaluate PARPi mechanisms of action

MOYANO, GINETTE ; CASTRO, MARÍA VICTORIA; MENAY, FLORENCIA; ERNST, GLENDA; REAL, JORGELINA NELLY; KORBENFELD, ERNESTO ; IGLESIAS, BRENDA ; MADAUSS, KEVIN ; STERLE, HELENA ; CAYROL, FLORENCIA ; CREMASCHI, GRACIELA ; MANSILLA, SABRINA FLORENCIA; GOTTIFREDI, VANESA

Rosario

Congreso; LIX Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research (SAIB); 2023

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

High-grade serous ovarian carcinoma (HGSOC) is the most common subtype of epithelial ovarian cancers (EOCs), representing 70% of them. Approximately 50% of HGSOC are associated with abnormalities in the homologous recombination (HR) pathway, as occurs with mutations in the BReast Cancer Genes 1 and 2 (BRCA1 and BRCA2), resulting in defective DNA repair known as “homologous recombination deficiency”. In addition, advanced stage ovarian cancer is frequently associated with the accumulation of ascitic fluids in the abdomen, known as ascites, which is made up of cellular and acellular components. Once removed, the ascitic fluid has no value from the clinical perspective but provides a source of tumor cells directly from patients, which can be used to validate results obtained from commercial cell line assays. They are also useful for evaluating their sensitivity to different drugs, in our case, Poly ADP-ribose polymerase inhibitors (PARPi), a therapeutic strategy used for the selective killing of HR-deficient tumor cells. We have set up a work protocol with the aim of generating primary cultures from ascitic fluid-derived tumor patient cells. Compared to other types of cancer, primary cultures of ovarian cancer cells are relatively easy to obtain due to their high viability, strong surface adhesion, and rapid cell division. With serial trypsinization, we were able to select the tumor cells and eliminate the rest of the cell populations. We carried out in vitro assays on the already established primary cultures, which allowed us to characterize key markers for this tumor type, such as HR, BRCA, p53, and CK7 status. Currently, we are evaluating the effect of different PARPi, looking for possible correlations between the sensitivity to these drugs and the previously mentioned markers.