RAB5A effect on metastasis of hepatocellular carcinoma cell line via altering the pro-invasive content of exosomes.

Tumor microenvironment exerts a critical role in cancer progression and metastasis. Exosomes, cell-cell communicators and major players of the tumor microenvironment are considered as a serious mediator of cancer metastasis. Here, we determined the effect of RAB5A gene on the hepatocellular carcinoma (HCC) cells particularly whether RAB5A could affect HCC metastasis via regulating the pro-invasive content of exosomes. In response to RAB5A knockdown, we analyzed the proliferation rate and migration capability of HCC cells. Then, we estimated changes in the total protein composition of exosomes via analyzing the expression of exosomal markers, CD63 and Alix. Thereafter, alterations of the pro-invasive content of exosomes were functionally evaluated using matrigel invasion assay. Our results revealed that knockdown of RAB5A could decrease HCC cell proliferation rate and migration capability significantly. Moreover, no significant changes in the expression of exosomal CD63 and Alix reflected that no differences might be occurred in protein composition of RAB5A knockdown cell-derived exosomes. Matrigel invasion assay functionally showed that exosomes-derived from RAB5A knockdown cells still had pro-invasive properties and their pro-invasive content was not affected in response to RAB5A knockdown. In conclusion, we believe that our results propose a new explanation about RAB5A and metastatic potentials of exosomes-derived from HCC cells.