Niraparib restricts intraperitoneal metastases of ovarian cancer by eliciting CD36-dependent ferroptosis.

Ovarian cancer (OC) is prone to peritoneum or omentum dissemination, thus giving rise to the formidable challenge of unresectable surgery and a dismal survival rate. Although niraparib holds a pivotal role in the maintenance treatment of OC, its effect on suppressing metastases during primary intervention remains enigmatic. Recently, we initiated a prospective clinical study (NCT04507841) in order to evaluate the therapeutic efficacy of neoadjuvant niraparib monotherapy for advanced OC with homologous recombination deficiency. An analysis of patient tumor burden before and after the niraparib challenge showed a remarkable vulnerability of OC intraperitoneal metastases to niraparib exposure. This killing capacity of niraparib was closely associated with the accumulation of fatty acids within the abdomen, which was confirmed by the increased susceptibility of tumor cells to niraparib treatment in the presence of fatty acids. In the context of abundant fatty acids, niraparib elevated intracellular levels of fatty acids and lipid peroxidation, leading to subsequent tumor cell ferroptosis in a p53 and BRCA-independent manner. Notably, under niraparib exposure, a critical fatty acid transporter CD36 was dramatically upregulated in tumors, facilitating excessive uptake of fatty acids. Pharmacological inhibition of either ferroptosis or CD36 impaired the anti-tumor activity of niraparib both in vitro and in murine intraperitoneal ID8 tumor models. Our findings demonstrate ferroptosis as a novel mechanism underlying the regression of OC metastases induced by niraparib, thereby offering tantalizing prospects for the frontline application of this agent in the management of OC.