Malignant ascites microenvironment induced macrophage reprogramming facilities epithelial ovarian cancer peritoneal metastasis

Macrophages form a primary immune cells population in tumor tissues and malignant ascites microenvironment (MAM). They can be activated and polarized into tumor-associated macrophages (TAM) by the embedded environment and promote tumor progression and metastasis However, the molecular mechanisms of MAM in macrophage polarization and the effects on epithelial ovarian cancer (EOC) metastatic progression remain elusive. Here, we found that that MAM modulates RhoA-GTPase-F-actin-Hippo signaling cascade in facilitating M2-like macrophage polarization that, in turn, promotes tumor dissemination. PUFA enriched magligant ascites microenvironment promote macrophage lipid oxidative phosphorylation and supression RhoA-GTPase-Yap1 axis. Genetic ablation Yap1 in macrophage exhibited M2-like polarization and enhanced ovrian tumor dissemination. Pharmacology inhibit Mst1/2 could rescue M2-like TAM polarization in MAM and alter the lipid oxidation of macrophages in MAM, more importantly, inhibit ovarian metastatic properties. Through comparasion primary TAM (P-TAM) and metastasis TAM (M-TAM), we proved that Hippo-Yap1 siganl results M-TAM with high M2/M1 ratio. These findings implicate critical functions of PUFA modulate RhoA-Hippo axis in facility TAM polarization and also suggest manipulation of PUFA metabolism or RhoA-Hippo siganl as a therapeutic strategy aganist EOC metastasis.