Ovarian cancer organoids for modeling drug response and discovering novel BRCA biomarkers

Tese de mestrado, Biologia Molecular e Genética, Universidade de Lisboa, Faculdade de Ciências, 2020 ; Ovarian cancer (OC) is a heterogeneous disease and represents the second leading cause of gynecologic cancer-associated death. Late presentation of the disease is frequent and is associated with a reduced survival rate partially justified by a limited offer of therapeutic options and a lack of predictive biomarkers. Treatment usually involves cytoreductive surgery, followed by adjuvant platinum-based chemotherapy, however most patients relapse, in many cases with platinum-resistant/refractory tumors. For high-grade serous ovarian carcinoma (HGSOC), the most common type of OC that frequently features defects in the homologous recombination repair (HRR) pathway, an alternative strategy relies on the use of poly[ADP-ribose] polymerase inhibitors (PARPi). These drugs induce synthetic lethality in tumors with homologous recombination deficiency (HRD), as is the case of HGSOC arising in the context of BRCA1/2 mutations, since BRCA proteins play a crucial role in the repair of DNA damage via HRR. Nevertheless, it is not yet possible to predict if tumors will respond to the available treatment regimens. Additionally, pathobiology of OC is poorly understood, mainly due to limitations in the available study platforms. Cancer cell lines and patient-derived xenografts are the most commonly used model systems to study OC, yet they hold several drawbacks that make them ineffective research tools. Such obstacles can be overcome by the use of the organoid technology. Cancer organoids, particularly patient-derived tumor organoids (PDTOs) are three-dimensional cell cultures derived from primary tumor cells, capable of self-renewal and self-organization. PDTOs maintain the morphophysiological and functional characteristics of their source tumors and have been shown to recapitulate tumor response to therapy. The goal of this project was to generate patient-derived ovarian cancer organoids to examine how their drug sensitivity ...