Small molecular anticancer agent SKLB703 induces apoptosis in human hepatocellular carcinoma cells via the mitochondrial apoptotic pathway in vitro and inhibits tumor growth in vivo

Inducing apoptosis is a promising therapeutic approach to overcome cancer. Here we described that a novel synthesized compound, 3-amino-N-(4-chlorobenzyl)-6-(3-methoxyphenyl)thieno[2,3-b]pyridine-2-carboxamide (SKLB703), exhibits antitumor activity via inducing apoptosis both in vitro and in vivo. Our results showed that SKLB703 inhibited the proliferation of a panel of human cancer cell lines, and human hepatocellular carcinoma cell line HepG2 was the most sensitive. The proliferation inhibitory effect of SKLB703 was associated with its apoptosis-inducing effect by activating caspase-3 and caspase-9 rather than caspase 8. Exposure of HepG2 to SKLB703 also resulted in Bax upregulation, Bcl-2 downregulation, cytochrome c release and mitochondrial transmembrane potential change in mitochondrial apoptotic pathway. Moreover, the decrease of phosphorylated p 44/42 mitogen-activated protein kinase and phosphorylated Akt was observed. SKLB703 suppressed the growth of established tumors in xenograft models in mice, whereas no toxicity was exhibited. TUNAL analysis showed that SKLB703 induced HepG2 tumor apoptosis. Taken together, the present study demonstrates that SKLB730 exhibits its antitumor activity through inducing apoptosis via mitochondrial apoptotic pathway. Its potential to be a candidate of anticancer agent is worth being further investigated.