Wen Shen2,†,
Xing Liu3,
Ting Zhang2,
Jun Ren2,
Yongjun Fan4 and
Jian Xu2,*
2College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou 310053, China
3School of Medicine, Jinggangshan University, Ji’an 343000, China
4National Centre for Stem Cell Research, Eskitis Institute for Drug Discovery, Griffith University, QLD 4111, Australia
Abstract Oridonin, an ent-kaurene diterpenoid extracted from the traditional Chinese herb Rabdosia rubescens, has multiple biological and pharmaceutical functions and has been used clinically for many years. While the antitumor function of oridonin has been corroborated by numerous lines of evidence, its anticancer mechanism has not been well documented. In this study, the pancreatic cancer cell line BxPC-3 was used as a model to investigate a possible anticancer mechanism of oridonin through examining its effects on cell viability. The results showed that oridonin affected cell viability in a time- and dose-dependent manner. After exposure to different oridonin concentrations, growth rates and cell cycle arrest of BxPC-3 cells were significantly reduced compared with untreated cells, suggesting its effects on proliferation inhibition. Detailed signaling pathway analysis by western blot analysis revealed that low-dose oridonin treatment inhibited BxPC-3 cell proliferation by up-regulating p53 and down-regulating cyclin-dependent kinase 1 (CDK1), which led to cell cycle arrest in the G2/M phase. A high-dose oridonin not only arrested BxPC-3 cells in the G2/M phase but also induced cell accumulation in the S phase, presumably through γH2AX up-regulation and DNA damage. In addition, our results showed that a cell subpopulation was stained with propidium iodide after oridonin treatment. Protein quantification showed that cleaved poly(ADP-ribose) polymerase (PARP) expression was increased after a high-dose oridonin treatment, especially after long-term exposure. Accompanied by the increased level of deactivated PARP in BxPC-3 cells, the apoptosis initiators caspase-3 and caspase-7 expressions were also significantly increased, suggesting that caspase-mediated apoptosis contributed to cell death.
Keywords oridonin; pancreatic cancer; BxPC-3 cells; proliferation; apoptosis
Received 2014-9-22
Accepted 2014-12-30
Funding This work was supported by the grants from the Qianjiang Talent Project of Zhejiang Province (No. 2013R10072), the Natural Science Foundation of Zhejiang Province (Nos. LY14H160037 and LY12H16007), and the Natural Science Foundation of Jiangxi Province (N
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