Cytosolic phospholipase A2? modulates cell-matrix adhesion via the FAK/paxillin pathway in hepatocellular carcinoma.

ABSTRACT: Objective:To explore the effect of cytosolic phospholipase A2? (cPLA2?) on hepatocellular carcinoma (HCC) cell adhesion and the underlying mechanisms. Methods:Cell adhesion, detachment, and hanging-drop assays were utilized to examine the effect of cPLA2? on the cell-matrix and cell-cell adhesion. Downstream substrates and effectors of cPLA2? were screened via a phospho-antibody microarray. Associated signaling pathways were identified by the functional annotation tool DAVID. Candidate proteins were verified using Western blot and colocalization was investigated via immunofluorescence. Western blot and immunohistochemistry were used to detect protein expression in HCC tissues. Prognosis evaluation was conducted using Kaplan-Meier and Cox-proportional hazards regression analyses. Results:Our findings showed that cPLA2? knockdown decreases cell-matrix adhesion but increases cell-cell adhesion in HepG2 cells. Microarray analysis revealed that phosphorylation of multiple proteins at specific sites were regulated by cPLA2?. These phosphorylated proteins were involved in various biological processes. In addition, our results indicated that the focal adhesion pathway was highly enriched in the cPLA2?-relevant signaling pathway. Furthermore, cPLA2? was found to elevate phosphorylation levels of FAK and paxillin, two crucial components of focal adhesion. Moreover, localization of p-FAK to focal adhesions in the plasma membrane was significantly reduced with the downregulation of cPLA2?. Clinically, cPLA2? expression was positively correlated with p-FAK levels. Additionally, high expression of both cPLA2? and p-FAK predicted the worst prognoses for HCC patients. Conclusions:Our study indicated that cPLA2? may promote cell-matrix adhesion via the FAK/paxillin pathway, which partly explains the malignant cPLA2? phenotype seen in HCC.

SUBMITTER: Guo P 

PROVIDER: S-EPMC6713643 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature