Suppression of actopaxin impairs hepatocellular carcinoma metastasis through modulation of cell migration and invasion

Abstract

Early reports suggested that actopaxin, a member of the focal adhesion proteins, regulates cell migration. Here we investigated whether actopaxin is involved in hepatocellular carcinoma (HCC) progression and metastasis. We examined actopaxin expression in human HCC samples using immunohistochemistry and western blotting. The functional and molecular effect of actopaxin was studied in vitro by overexpression in a nonmetastatic HCC cell line, as well as repression in a metastatic cell line. The in vivo effect of actopaxin repression was studied in nonobese diabetic and severe combined immunodeficient mice. We found that actopaxin was frequently overexpressed in human HCC patients and its overexpression positively correlated with tumor size, stage, and metastasis. Actopaxin expression also correlated with the metastatic potential of HCC cell lines. Actopaxin overexpression induced the invasion and migration ability of nonmetastatic HCC cells, whereas down-regulation of actopaxin reverted the invasive phenotypes and metastatic potential of metastatic HCC cells through regulating the protein expression of certain focal adhesion proteins including ILK, PINCH, paxillin, and cdc42, as well as regulating the epithelialmesenchymal transition pathway. Furthermore, there was a close association between actopaxin and CD29. HCC cells with stronger CD29 expression showed a higher actopaxin level, whereas actopaxin repression attenuated CD29 activity. Finally, actopaxin down-regulation enhanced the chemosensitivity of HCC cells towards oxaliplatin treatment by way of a collective result of suppression of survivin protein, b-catenin, and mammalian target of rapamycin pathways and up-regulation of p53. Conclusion: This study provides concrete evidence of a significant role of actopaxin in HCC progression and metastasis, by way of regulation of cell invasiveness and motility, an epithelial-mesenchymal transition process, and chemosensitivity to cytotoxic drugs. (HEPATOLOGY 2013;58:667-679) H epatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. 1Most HCC patients die from locally advanced or metastatic disease in a relatively short period of time, and the mechanisms responsible for HCC progression and metastasis remain a major challenge to researchers in this field. It is believed that the elucidation of molecular mechanisms involved in HCC progression and metastasis is important for development of HCC therapeutic agents.Tumor invasion and metastasis are complex processes requiring the ability of tumor cells to interact with the extracellular matrix. Major cell surface receptors that mediate these interactions are integrins.2 Several studies have demonstrated the important roles of b1-integrin in the growth, invasiveness, and metastatic potential of HCC, 3-5 as well as in protecting cancer cells against chemotherapeutic-drug-induced apoptosis.6 Focal adhesion proteins serve as a structural and signaling nexus connecting integrins and the dynamic Abbreviations: 97L-LUC cells, luciferase incorporated...

Focal Adhesion Proteins α- and β-Parvin are Overexpressed in Human Colorectal Cancer and Correlate with Tumor Progression

“…While nuclear targeting of α-parvin has been demonstrated in some cell types in vitro, consistent with previous studies in other tumors, we showed by immunohistochemistry and immunofluorescence that immunoreactivity for α-parvin in CRC was confined to the cytoplasm of cancer cells (6,14,22,23). On the other hand, we observed nuclear localization of β-parvin in 25% of our cases.…”

“…Consistently, knockdown of ILK in human intestinal epithe-lial cells caused reduced expression of αand β-parvin (28). Ectopic overexpression of α-parvin in HCC cell lines resulted in increased ILK expression and severely reduced ILK protein levels were also observed in β-parvin deficient zebrafish embryos (14,29). As already outlined, parvins interact with ILK in cells to form a heterotrimeric IPP complex, the formation of which has been shown to stabilize its members by protecting them from degradation (30).…”

“…Parvin partners ILK and PINCH are overexpressed in CRC and correlate with aggressive tumor features (15,16). Recent studies suggest that altered expression of parvins relates to tumorigenesis (13,14). Here, we provide novel evidence that αand β-parvin are overexpressed in human colorectal cancer and represent markers of an aggressive, invasive and metastatic tumor phenotype.…”

“…In accordance, overexpression of α-parvin in human hepatocellular carcinomas (HCC) correlates with metastasis and decreased survival (13). In further support, α-parvin has been shown to induce HCC cell invasion and metastasis and phosphorylation of α-parvin has been demonstrated to be required for matrix degradation and cell invasion (14,26). However, conflicting results have been reported for βparvin.…”

New insights into molecular diagnostic pathology of primary liver cancer: Advances and challenges

“…From that HCC can be divided into the following subgroups: high invasiveness and low invasiveness; high recurrent risk and low current risk; and short-term survival and long-term survival. Many genes or protein biomarkers that have abnormal expression in HCC tissues have been recently reported as shown in Table 1 [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”