Abstract. Jiedu Xiaozheng Yin (JXY), a polyherbal formula of traditional Chinese medicine (TCM), has been used to treat various kinds of cancer in China. However, the mechanism of its anticancer activity has yet to be elucidated. Air-dried herbs were extracted with reagents of different polarity. HepG2 cells were treated with different doses of ethyl acetate extract (EE-JXY) and chloroform extract (CE-JXY) for 24 h. Cell viability was detected by MTT assay. Colony formation ability was also evaluated. Cell cycle was evaluated by FACS. Tumor bearing BALB/c nude mice was treated with EE-JXY (0.06 g/kg) for 20 days. Tumor volume and weight were monitored. The percentage of PCNA-positive cells and the level of G1 phase proteins [cyclin-dependent kinase2 (CDK2), cyclin-dependent kinase4 (CDK4), cyclin D and cyclin E and G2 phase proteins [cyclin-dependent kinase1 (CDK1), cyclin A and cyclin B] were detected by immunohistochemistry and western blotting.EE-JXY and CE-JXY dose-dependently inhibited the growth of HepG2 cells (P<0.01 for both). Furthermore, EE-JXY inhibited the formation of cell colonies and blocked the cell cycle to G1 phase in a dose-dependent manner (P<0.01 for all). EE-JXY showed an obviously antitumor effect in vivo (P<0.05). Further investigation showed that EE-JXY decreased the proliferation index of tumors (P<0.01) through increasing the expression of G1-related proteins (cyclin D and cyclin E, P<0.05 and P<0.01). These results suggested that JXY inhibits the growth of HepG2 cells at least via arresting the cell cycle at the G0/G1 phase.
IntroductionHepatocellular carcinoma (HCC) is listed as the fifth most common malignancy in the world. Although surgical treatment and non-surgical therapeutic modalities such as chemotherapy, radiotherapy and interventional therapy have been employed, HCC is rarely curative (1,2). For this reason more and more patients and oncologists are seeking alternative medicines to improve the curative rate of HCC. Traditional Chinese medicine (TCM) has been widely used in China to treat HCC because it can improve immune function of patients and alleviate chemoradiotherapy-related side effects (3).In TCM, herbs commonly used for cancer treatment can be divided into two categories. One is nutritious and tonic herbs and the other is heat-clearing and detoxification herbs. Nutritious and tonic herbs (Fuzheng herbs) act by improving the immune function to fight cancer (such as Astragalus, Ganoderma lucidum and ginseng) (4-6). Heat clearing and detoxication herbs (Qingre Jiedu herbs) may directively kill tumor cells [such as Hedyotis diffusa Willd (HDW), Sophora flavescens (SF), Pseudobulbus Cremastrae (PC), Prunella, Bidens, banzhilian] (7-9). In TCM, cancer is considered to be caused by accumulation of foreign toxins, and cancer itself is also considered to be a toxin that is harmful to human body. The above herbs may contain ingredients that can inhibit proliferation and promote apoptosis of tumor cells. For example, we found that HDW water extract may inhibit proliferation o...