Abstract. Currently, liver cancer is the sixth most prevalent cancer and the third most common cause of cancer-related death. However, effective chemotherapeutic drugs with low drug resistance and few side-effects for the clinical treatment of liver cancer are lacking. Therefore, the search for novel drugs to compensate for the defects of existing drugs is urgently needed. Herein, we successfully screened an extract named from Stellera chamaejasme L. (SCL), a historically confimed antitumor plant, through a novel extraction platform. In the present study, we firstly screened the anticancer effect of ESC by the sulforhodamine B (SRB) cell proliferation assay in a wide range of malignant cell lines, including A549, NCI-H157, NCI-H460, SK-HEP-1 and HepG2. With the highest inhibitory rate in hepatocarcinoma cells, we further identified the tumor-suppressive efficacy and the safety of ESC in an H22 hepatocarcinoma xenograft model in vivo. In a mechanistic study, flow cytometry and western blot analysis were performed to evaluate the effects of ESC on the induction of cell apoptosis, intervention of cell cycle distribution and its influence on key G2/M-phase regulators. The results showed that ESC significantly inhibited the cell growth of liver cancer cell lines. Accordingly, the tumor inhibition rate was also increased following ESC administration with little systemic toxicity in H22-transplanted mice. Mechanistically, ESC caused obvious G2/M-phase arrest in both the SK-HEP-1 and HepG2 cell lines without cell apoptosis. Furthermore, cyclin B1 was downregulated, while the phosphorylation level of CDK1 was increased in response to ESC treatment. All these data confirmed that ESC possesses potent anti-proliferative efficacy for hepatocarcinoma through the induction of cyclinmediated cell cycle arrest. Thus, ESC is a promising candidate for hepatocarcinoma treatment in the future.
IntroductionAs one of the major global public health issues, cancer greatly threatens human survival and has become the leading cause of mortality of humankind in this century (1). Clinically, during the rapid development of anticancer strategies, chemotherapy has consistently played an important role in cancer treatment. To date, classical botanical agents, as represented by paclitaxel or vincristine, are still first-line drugs and are widely applied as the primary choice against multiple malignancies (2). Benefitting from these agents, treatment effectiveness and the survival rate of cancer patients have greatly improved in recent years. However, in spite of the satisfactory tumor-suppressive activities, with their extensive application worldwide, growing evidence reveals that side-effects and drug resistance are still the leading obstacles largely limiting the clinical use of classic tumor-toxic agents (3).In recent years, liver cancer has become one of the most prevalent types of cancer and is the third most common cause of cancer-related mortality (4,5). Notably, its incidence and mortality rank second among Chinese cancer patients (6) an...