Silencing activating transcription factor 2 promotes the anticancer activity of sorafenib in hepatocellular carcinoma cells.

Abstract

The present study aimed to investigate the anticancer effect of sorafenib combined with silencing of activating transcription factor 2 (ATF2) in hepatocellular carcinoma (HCC) cells and to assess the underlying molecular mechanisms. Huh-7 HCC cell line was selected for the present study. Small interfering RNA (siRNA)-ATF2 sequence was constructed to silence ATF2 expression. The experiment was divided into 6 groups: i) Control; ii) vector; iii) sorafenib (6.8 µM); iv) vector+sorafenib; v) siRNA-ATF2; and vi) siRNA-ATF2+sorafenib groups. Cell proliferation, apoptosis, migration and invasion were detected following treatments with sorafenib and/or ATF2 silencing. Additionally, expression of tumor necrosis factor (TNF)-α and c-Jun N-terminal kinase 3 (JNK3) was detected using reverse transcription-quantitative polymerase chain reaction and western blotting. The current findings revealed that siRNA-ATF2 significantly reduced ATF2 expression. Cell proliferation, migration and invasion abilities in the sorafenib and siRNA-ATF2 groups were significantly reduced compared with the control group (P<0.05). Apoptotic rate in the sorafenib and siRNA-ATF2 groups was significantly increased compared with the control group (P<0.05). The mRNA and protein expression levels of ATF2 in the sorafenib or siRNA-ATF2 groups was significantly reduced when compared with control group. The phosphorylation of ATF2 was also reduced following sorafenib treatment or ATF2 silence. Although JNK3 mRNA expression level was not affected, the phosphorylation level of JNK3 was significantly promoted following sorafenib treatment or ATF2 silencing. Additionally, TNF-α mRNA and protein expression levels were increased following sorafenib treatment or ATF2 silencing. It is of note that siRNA-ATF2 treatment promoted the anticancer activity of sorafenib in Huh-7 cells. Additionally, siRNA-ATF2+sorafenib treatment combined additionally promoted TNF-α expression and phosphorylation of JNK3. Combined siRNA-ATF2 and sorafenib treatment had a greater anticancer effect compared with sorafenib or ATF2 silencing alone. The possible mechanism involved in the anticancer effect of sorafenib and ATF2 silencing may be associated with the activation of the TNF-α/JNK3 signaling pathway.