Ezrin plays a key role in cancer cell spheroid formation in soft environments

A unique form of metastasis characterizes ovarian cancer (OC), in which tumors grow either suspended in the peritoneal fluid or attached to peritoneal tissues. Notably, the mechanisms underlying metastasis in ascitic fluid remain poorly understood. A critical step in this process is the formation of cancer cell spheroids. We hypothesize that spheroid generation depends on actin cytoskeleton-associated proteins at the cell cortex. In this context, Ezrin, a member of the ERM (Ezrin-Radixin-Moesin) family protein, emerged as a strong candidate. To investigate, we established a 3D culture model using SKOV3 cells and assess spheroid formation under different conditions. We found that Ezrin-depleted cells, failed to form spheroids in soft agar, a phenotype reversed by reintroducing wild-type Ezrin, ConA treatment, increasing agar concentration, or mimicking the physical interactions of neighboring cells within a spheroid. Complementary experiments in xenograft nude mouse models confirmed the essential role of Ezrin in tumor development. Notably, Intraperitoneal injection of spheroids generated in vitro overcame the effects of Ezrin depletion. Together, these findings underscore the role of Ezrin as a structural component of the cell cortex, crucial for tumor formation in soft environments, and highlight the broader relevance of ERM proteins in intraperitoneal metastasis in OC.