NSC 74859 enhances doxorubicin cytotoxicity via inhibition of epithelial-mesenchymal transition in hepatocellular carcinoma cells.

Doxorubicin-based therapy is not effective for the treatment of hepatocellular carcinomas (HCCs), which often undergo epithelial-mesenchymal transition (EMT) during tumor progression. Activation of signal transducer and activator of transcription 3 (STAT3) is associated with chemosensitivity and may contribute to EMT during HCC chemotherapy. Low doses of NSC 78459 (a novel STAT3 inhibitor) have little effect on HCC cell proliferation, but efficiently inhibit STAT3. HuH-7, Hep3B, and HepG2 cells, with epithelial phenotypes, show significantly enhanced doxorubicin cytotoxicity following co-treatment with NSC 74859, whereas mesenchymal SNU-449 cells show no such enhancement. NSC 74859 inhibits STAT3 activity and suppressed doxorubicin-induced EMT in epithelial HCC cells. siRNA-mediated STAT3 knockdown resulted in EMT inhibition, which led to attenuation of NSC 74859-mediated chemosensitivity. Our data indicate NSC 74859 co-administration enhances doxorubicin cytotoxicity by inhibiting STAT3 in epithelial HCC cells. STAT3 deactivation and associated EMT attenuation contribute to the synergistic anti-tumor effects of combined NSC 74859/doxorubicin therapy.

Hu QD ，Chen W ，Yan TL ，Ma T ，Chen CL ，Liang C ，Zhang Q ，Xia XF ，Liu H ，Zhi X ，Zheng XX ，Bai XL ，Yu XZ ，Liang TB ... -  《-》

ARK5 promotes doxorubicin resistance in hepatocellular carcinoma via epithelial-mesenchymal transition.

AMP-activated protein kinase family member 5 (ARK5) overexpression has been reported in many human cancers, and ARK5 is associated with poor prognosis in hepatocellular carcinoma (HCC). However, whether ARK5 is involved in HCC chemoresistance is unclear. The present study aimed to investigate the role of ARK5 in HCC chemoresistance and the underlying mechanism. In this study, we found that SNU387 and SNU449 HCC cell lines overexpressing ARK5 displayed low doxorubicin sensitivity compared to Huh7 and Hep3B HCC cell lines with ARK5 low-expression. And knockdown of ARK5 increased the doxorubicin sensitivity in all HCC cell lines in the manner of inhibiting cell proliferation. Western blotting and immunofluorescence both showed that ARK5 knockdown upregulated E-cadherin and downregulated vimentin, which was consistent with the knockdown of TWIST, indicating ARK5 was involved in epithelial-mesenchymal transition (EMT). Moreover, suppressing ARK5 by siRNA restored E-cadherin and vimentin expression induced by doxorubicin treatment or hypoxia culture. Our results indicated ARK5 confers doxorubicin resistance in HCC via inducing EMT.

Xu T ，Zhang J ，Chen W ，Pan S ，Zhi X ，Wen L ，Zhou Y ，Chen BW ，Qiu J ，Zhang Y ，Yang Q ，Feng X ，Bai X ，Liang T ... -  《-》

STAT3 cooperates with Twist to mediate epithelial-mesenchymal transition in human hepatocellular carcinoma cells.

Zhang C ，Guo F ，Xu G ，Ma J ，Shao F ... -  《-》

NSC 74859-mediated inhibition of STAT3 enhances the anti-proliferative activity of cetuximab in hepatocellular carcinoma.

Cetuximab [an epidermal growth factor receptor (EGFR) inhibitor], which was shown to be effective in rectal and non-small cell lung cancers (NSCLCs), was only modestly effective in clinical trials of hepatocellular carcinoma (HCC). STAT3, which is thought to be a determinant of HCC sensitivity to antitumour drugs, may be involved. To evaluate the efficacy of combination therapy using cetuximab and NSC 74859 (a novel STAT3 inhibitor) in EGFR and STAT3 overexpressing hepatoma cells. Hepatoma cell lines were treated with cetuximab, NSC 74859 or a combination of both drugs. Efficacy of treatment was evaluated by determining cell viability using MTT assays and proliferation by cell counting. Expression and activation of STAT3 were determined using Western blot analysis. We evaluated the role of STAT3 in single and combination therapy using siRNA-mediated knock-down of STAT3 or STAT3 overexpression strategies. HepG2 and Huh-7 cells, which had lower levels of pSTAT3 than SK-HEP1 cells, were more sensitive to cetuximab treatment when compared with SK-HEP1 cells. Although none of these cell lines was sensitive to NSC 74859 alone, NSC 74859 potentiated the antiproliferative effect of cetuximab in all three cell lines. siRNA knock-down of STAT3 increased the sensitivity of these cell lines to cetuximab, whereas STAT3 overexpression antagonized these effects. Enhanced growth inhibition in hepatoma cells treated with both NSC 74859 and cetuximab suggests that cetuximab resistance is probably mediated via STAT3. Combination therapy using both inhibitors of EGFR and STAT3 signalling warrants further investigation under in vivo condition.

Chen W ，Shen X ，Xia X ，Xu G ，Ma T ，Bai X ，Liang T ... -  《-》

FBW7 increases chemosensitivity in hepatocellular carcinoma cells through suppression of epithelial-mesenchymal transition.

Yu J ，Zhang W ，Gao F ，Liu YX ，Chen ZY ，Cheng LY ，Xie SF ，Zheng SS ... -  《Hepatobiliary & Pancreatic Diseases International》