Subclonal β-catenin/YAP signaling heterogeneity accelerates ovarian cancer metastasis through a senescence-associated secretory phenotype.

Intratumoral heterogeneity in metastatic cancers complicates effective treatment, as distinct tumor subclones display varying drug sensitivities and metastatic capabilities, interacting through mechanisms that remain poorly understood. In this study, we utilized an isogenic ovarian cancer cell pair distinguished by differential β-catenin signaling: non-metastatic (NM) cells with low β-catenin and highly metastatic (HM) cells with elevated β-catenin signaling. Co-engrafting NM and HM cells synergistically enhances peritoneal metastasis compared to either subclone alone. Immunohistochemical analysis revealed a mosaic β-catenin expression in mixed tumors, recapitulating the heterogeneity observed in clinical ovarian cancer cases. Notably, both NM cells and β-catenin-knockout HM cells exhibited an intrinsic senescence-associated secretory phenotype (SASP), mechanistically driven by Hippo/YAP signaling, which was suppressed by β-catenin in HM cells. This phenotype in turn facilitated the metastatic dissemination of β-catenin-high subclones through paracrine signaling. Importantly, mixed in vivo tumors were more susceptible to treatment with fisetin, a senolytic agent, and YAP inhibition, leading to marked reduction in metastatic burden. Overall, our findings demonstrate the pre-existence of senescence-like tumor cells in untreated conditions and reveal a novel cooperative mechanism in which β-catenin heterogeneity facilitates ovarian cancer progression through SASP-mediated subclonal interactions. These results provide a basis for targeted therapeutic strategies to disrupt intratumoral communication and improve treatment outcomes in metastatic ovarian cancer.