Effect of silencing HIF-1α by RNA interference on adhesion and invasion of the human nasopharyngeal carcinoma cell line CNE-1

Abstract

To investigate the effects of HIF-1α on adhesion and invasion of human nasopharyngeal carcinoma CNE-1 cells under hypoxia and underlying molecular mechanisms. CoCl₂was used to mimic tumor hypoxic microenvironment. mRNA and protein expressions of HIF-1α, E-cadherin and CXCR4 in CNE-1 cells at different hypoxic time phases were detected by RT-PCR and ELISA respectively. The influences of silencing HIF-1α using RNA interference on E-cadherin and CXCR4 expressions were evaluated. Adhesion test Transwell invasion test were used to evaluate the effects of HIF-1α gene silencing on cell adhesion and invasion. Under hypoxia, HIF-1α mRNA expression in CNE-1 cells was stable, but its protein expression increased obviously (P<0.05). Both mRNA and protein expressions of E-cadherin were decreased significantly with prolonged hypoxia, while mRNA and protein expressions of CXCR4 increased significantly (P<0.05). After silencing HIF-1α gene, expression of E-cadherin protein was up-regulated, but with down-regulated expression of CXCR4 protein, with a decrease significantly in adhesion rate or invasive cell number of CNE-1 cells (P<0.05). Hypoxia can increase HIF-1α protein expression in nasopharyngeal carcinoma cell line CNE-1. Silencing HIF-1α by RNA interference can reduce inhesion and invasion abilities of CNE-1 cells, which may be mediated by down-regulating E-cadherin expression and up-regulating CXCR4 expression.