Antiproliferative Effect Of Paeonol On Human Gastric Cancer Cell Lines In Vitro And In Vivo And The Possible Mechanism

Stomach cancer (gastric cancer, GC) is one of the most common malignancies. Habitat all malignancies in certain parts of the country itself the top causes of death. Modern medicine suggest that genes and immune dysfunction, eating salted food produced nitrite, barbecue foods have 3-4 Phe spent with the high incidence of gastric cancer. Immune surveillance and control of low immune function is one of the major reasons. The treatment for gastric cancer includes surgery, chemotherapy, biological therapy, Chinese medicine treatment, as well as the main treatment with 5-fluorouracil (5-FU), mitomycin C (MMC). Adriamycin (ADM) - based chemotherapy drug is an important component of comprehensive treatment of gastric cancer, but has bone marrow toxicity, liver and kidney toxicity and side effects such as gastrointestinal reactions, there is still much to be gained in efficiency. In addition, the tumor resistance phenomenon, which has occurred in the course of chemotherapy is a major problem in cancer treatment troubled, often lead to the failure of chemotherapy. Chinese herbal medicine is effective in treating cancer with low toxicity and increasingly attracted people's attention. In recent years, scientists on the mechanism of anti-tumor herbs gradually deepens, more and more effective components have been isolated, and different levels of resistance in the mechanism of the study. Searching for a new natural antineoplastic agent has become a hotspot. Paeonol (Pae), a major active component extracted from the herb Pycnostelma paniculatum (Bunge) K.S., and the root of the plant Paeonia Suffr- uticosa Andrew, possesses extensive pharmacological activities such as sedation, hypnosis, antipyresis, analgesic, antioxidation, antiinflammation, and immunoregulation. In our previous study, the antineoplastic activity of Pae has been demonstrated in both cell lines such as K562, T6-17, Bel-7404, and Hela, and in animal models bearing HepA hepatocarcinoma. The present study was designed to investigate the growth- inhibitory effect of Pae with chemotherapeutic drugs in mice Forestomach carcinoma cell lines MFC,human gastric cancer cell lines SGC-7901 and tumor-bearing mice and the possible mechanism, in order to develop an effective combination therapy for GC.1. Effect of Pae on the proliferation of human gastric cancer cell lines SGC-7901 and mice Forestomach carcinoma cell lines MFCThe antiproliferative effect of Pae on SGC-7901 and MFC cell lines in vitro was measured by MTT assay. The results suggested that Pae at concentrations of 7.81²50mg·L^-1, had inhibitory effect on the proliferation of both SGC-7901 and MFC cells. The higher the concentration of Pae was, the stronger the cytotoxic effect reached, which suggested obvious dose-dependent manner of Pae. The r values of dose-effect curves for single-agent Pae on both SGC-7901 and MFC cell lines were 0.9883 and 0.9800 respectively. The IC50 values were82.60 mg·L^-1 (SGC-7901) and 60.10 mg·L^-1 (MFC).2. Anti-tumor effect of Pae in vivo of MFC bearing mice modelPae ig suppressed the tumor growth significantIy in MFC bearing mice model. The tumor-inhibitory rates were 37% and 54% when the mice were administered with Pae at doses of 100 mg·kg^-1·d^-1 and 400 mg·kg^-1·d^-1,respectively,for l1 days.There were 15 mice deceased in 4 treated groups with 72 mice(4 in the group with 100 mg·kg^-1·d^-1,4 in the group with 200 mg·kg^-1·d^-1,6 in the group with 400 mg·kg^-1·d^-1 and 1 in the group with 5-FU 2.5 mg·kg^-1·d^-1). The body weight of mice afler Pae administration increased significantly,and no obvious toxic and side effects were observed,suggesting Pae is safe in the present experimental condition.3.Pae induced apoptosis of tumor cells3.1 Morphological observation for Pae-induced apoptosis of tumor cellsMorphological evidence of apoptosis was demonstrated by using acridine orange (AO) fluorescence staining. The results showed that AO permeated through cell membrane and made the nuclei appear green and chromatin appear yellow. The two cell lines treated with Pae showed the typically apoptotic changes, such as chromatin condensation, membrane blebing, deformed and fragmented nuclei, and so on.3.2 Analysis of Pae-induced apoptosis of tumor cells by flow cytometryA Flow Cytometry (FCM) assay was performed to analyze apoptotic rate of SGC-7901 and MFC cells treated with Pae at concentrations from 7.81 to 125 mg·L^-1 for 24h. The sub-G1 peak appeared before G1 phase, which represents apoptotic cell population, was observed clearly in the two cell lines treated with Pae with dose -dependent manner, which suggest that that anti-tumor activity of Pae may be related to its induction of tumor cell apoptosis.4 Molecular mechanism of Pae-induced tumor cell apoptosisImmunohistochemical S-P methods were used to measure the expression of apoptosis-related protein including bax, bcl-2 in human gastric carcinoma cell line SGC-7901,mice forestomach cancer cell line MFC and MFC bearing mice model. Jiangsu Jetta morphological image analysis system was used to analyze the results. It was found that Pae could up-regulate the expression of bax, and down-regulate the expression of bcl-2. Dose-effect relationship was also observed. These results suggest that Pae-induced tumor cell apoptosis may be related to its regulation of apoptosisassociated protein expression.5. ConclusionThe results in the present study demonstrated that Pae had anti-tumor effects on human gastric carcinoma cell line SGC-7901,mice forestomach cancer cell MFC in vivo and in vitro with a dose-dependent maner; These effects might be related its induction of tumor cell apoptosis.