Abstract A43: Centrosome amplification favors survival and impairs ovarian cancer progression

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. The most common subtype of EOC is high-grade serous (HGSOC), which responds at least initially to chemotherapy but has a worse overall prognosis. Genomic, transcriptomic, and proteogenomic profiling of HGSOC suggested a whole spectrum of molecular diversity, including homologous recombination pathway deficiencies (HRD). The centrosome is the main microtubule (MT)-organizing center of animal cells. It facilitates the accuracy of chromosome segregation during mitosis and influences cell polarity and migration. The presence of more than two centrosomes in a cell, centrosome amplification, has long been associated with tumorigenesis. However, little is known about the real status of centrosome numbers in human cancers and whether numerical alterations are solely associated with poor prognosis. We screened 100 samples of primary EOCs including 88 HGSOC, using immunofluorescence and state-of-the-art microscopy, to determine the centrosome-nucleus index (CNI). We integrated these data with genomic alterations, HRD status, and patient outcome. We found that EOCs are highly heterogeneous, with infrequent but strong centrosome amplifications leading to higher CNI than in healthy tissues. Strikingly, while a correlation between CNI and genomic alterations, such as aneuploidy or chromosome rearrangements, could not be established, we found that high CNI correlates with increased patient survival and sensitivity to chemotherapy, independently of HRD status. Using ovarian cancer cellular models to manipulate centrosome numbers and patient-derived xenografts (PDXs), we found that higher CNIs can positively impact the response to chemotherapy and inhibit peritoneal cell dissemination. Citation Format: Jean-Philippe Morretton, Aurelie Herbette, Camille Cosson, Bassirou Mboup, Aurelien Latouche, Pierre Gestraud, Tatiana Popova, Marc-Henri Stern, Fariba Nemati, Didier Decaudin, Guillaume Bataillon, Veronique Becette, Didier Meseure, Andre Nicolas, Odette Mariani, Claire Bonneau, Jorge Barbazan, Anne Vincent-Salomon, Fatima Mechta-Grigoriou, Sergio Roman-Roman, Roman Rouzier, Xavier Sastre-Garau, Oumou Goundiam, Renata Basto. Centrosome amplification favors survival and impairs ovarian cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A43.