Berberine activates caspase-9/cytochrome c-mediated apoptosis to suppress triple-negative breast cancer cells in vitro and in vivo

Publication date: November 2017
Source:Biomedicine & Pharmacotherapy, Volume 95
Author(s): Yuwan Zhao, Zuolei Jing, Jian Lv, Zhiwei Zhang, Jintao Lin, Xuejiao Cao, Zinan Zhao, Pixu Liu, Weifeng Mao
Berberine (BBR) is an isoquinoline alkaloid isolated from Cotridis rhizoma and exhibits multiple biological roles including anti-microbe, anti-inflammation and anti-tumor activities. In this study, two triple-negative breast cancer cell (TNBC) lines, MDA-MB-231 and BT549, were used to investigate the effect of BBR on growth of TNBC in vitro and in vivo. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the viability of cells treated with BBR. After 48h treatments, a 50% inhibitory concentration (IC50) of BBR to BT549 and MDA-MB-231 cells are at 16.575±1.219μg/ml and 18.525±6.139μg/ml respectively. BBR reduced colony formation of BT549 and MDA-MB-231 cells. The wound-healing assay showed BBR decreased breast cancer cell migrations (P<0.01). AnnexinV-PI staining assay confirmed BBR induced cellular apoptosis. The expressions of caspase-3, caspase-9, Bcl-2 and Bax were detected by western blot, which showed BBR activated caspase-3, 9 and Bax, but down-regulated Bcl-2 expression. BBR promoted the release of cytochrome c through the immunofluorescent analysis (P<0.01). We also found BBR increased the level of cellular γH2AX and increased the expression of Ligase4, which suggests BBR induces the double-strand breaks (DSB). These results thus demonstrated that BBR induced DSB, subsequently increased the release of cytochrome c and eventually triggered the caspase9-dependent apoptosis. In addition, we used a MDA-MB-231 mouse-xenograftmodel to evaluate the effect of BBR on tumor growth. BBR suppressed tumor growth and increased caspase-9 levels in xenograft tumors through immunohistochemistry analysis (P<0.01). Taken together, these results demonstrate that BBR activates caspase-9/cytochrome c-mediated apoptosis to inhibit the growth of TNBC breast cancer cells in vitro and in vivo.



http://ift.tt/2ieo5FJ