| Gastric cancer (Gastric carcinoma) is a serious hazard to human health, it is one of the most common malignant tumors, the incidence rate of10-150/10million around the world each year about934000new cases, ranking the second of malignant tumors; About700000people die every year, the fourth mortality among all the tumor (10.4%), the common treatment methods are operation, radiotherapy, and chemotherapy. Operation with radiotherapy is one of the main means. However, radiotherapy is often due to the radiation damage to normal tissue or tumor resistance to radiation effects, the sensitizer often be used to enhancing the killing effect on tumor cells, choose good radiosensitizer has become a new way to optimize the treatment of gastric cancer. Evodiamine (EVO) is extracted from nearly ripe fruit of rutaceae evodia. In recent years, numerous studies have shown that EVO has anticancer activity on malignant melanoma, prostate cancer, liver cancer, thyroid cancer, stomach cancer and colon cancer and even multi-drug resistant tumor cells. At the present time, we have not seen any reports about EVO increase sensitizing effect of radiation on Gastric cancer. This study aims to explore the Mechanism of EVO combined with radiation on gastric cancer SGC7901BGC823cells, in order to provide a new ideas for clinical radiotherapy in increasing sensitivity agent selection.This study is divided into two parts:1. EVO inhibited proliferation and affected the radio sensitizing effect of SGC7901BGC823cells Use logarithmic growth phase as the research object, Cells growth inhibition was assessed by MTT after treated with indicated concentrations and time, results showed that Survival rates of SGC7901BGC823cells were decreased as increase of evodiamine concentration and time. The radio sensitization of evodiamine was measured by MTT assay. The cell survival rates of radiotherapy and evodiamine with radiotherapy groups were both decreased with the increase exposal doses and time. However, the cell survival rates of evodiamie with radiotherapy group was obviously lower than radiotherapy group on indicated exposal doses and time (P<0.05). The Do and SER were obtained with the colony formation assay after different treatments. The Do and SER of evodiamine with radiotherapy group were Do SGC7901(A4.5B4), BGC823(A4.3 B3.9) SER SGC7901(A1.21.21.41.5B1.11.21.41.5) BGC823(A1.01.21.41.5B1.01.21.41.4).2. The radio sensitizing effect mechanism of EVO on SGC7901BGC823cells PI staining was used to compare different doses of radiation treatment for cell cycle distribution and EVO combined with different doses of radiation (2,4,6,8Gy), stagnated cells at G2/M phase SGC7901(A42%42%55%69%B36%48%51%64%) BGC823(A31%36%37%44%B24%30%36%37%) were significantly higher than radiotherapy alone group SGC7901(32%32%34%36%) BGC823(14%20%26%32%)(P<0.05), and with increasing radiation dose this is more obvious; western-blot detected that expression of caspase3, the results show that the expression of caspase3of different dose EVO+radiation group compared with radiotherapy alone group were increased.Conclusion EVO has obvious radiation sensitizing effect on the SGC7901, BGC823cells,and the radiosensitivity of group A is more obvious than that of group B, and its mechanism may be related to radiation combined with EVO leads to cell cycle arrest in the G2/M phase, and the activation of Caspase3which promote the apoptosis. |
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