AIM:To investigate radiosensitization effect of apatinib, a vascular endothelial growth factor (VEGF) receptor2 tyrosine kinase inhibitor, on human gastric carcinoma cell line SGC-7901 and its mechanism.METHODS:SGC-7901 cells were divided into control group, apatinib group, radiotherapy group and combination group.The cell viability was measured by CCK-8 assay.The changes of cell apoptosis and cell cycle were analyzed by flow cytometry.The protein levels of cell apoptosis biomarkers, such as PARP, cleaved caspase-9, cleaved caspase-3 and Bcl-2, and cell proliferation biomarkers, p-PLCγ1 and p-ERK1/2, were detected by Western blot.γ-H2AX expression was detected by immunofluorescence.RESULTS:Compared with apatinib group and radiation group, the cell viability was inhibited after treatment with both apatinib and X-ray (P<0.01).The protein levels of cell proliferation markers p-PLCγ1 and p-ERK1/2 were down-regulated.The cell apoptosis was enhanced (P<0.01).The protein levels of cell apoptosis makers such as PARP, cleaved caspase-9 and cleaved caspase-3 were up-regulated, while Bcl-2 was down-regulated.The disappearance of γ-H2AX foci in the nucleus was delayed, indicating that apatinib impaired the repair of radiation-induced DNA double-strand breaks.The proportion of G2 phase was significantly increased (P<0.01).The combination treatment had more significant effect on SGC-7901 cells than treating with apatinib or radiotherapy alone.CONCLUSION:Apatinib increases the radiosensitivity of gastric cancer cells via blocking VEGF pathway.

Background:Inflammation-based indexes have been used to predict survival and recurrence in cancer patients.Systemic immune-inflammation index (SII) was reported to be associated with prognosis in some malignant tumors.In the present study,we aimed to explore the association between SII and the prognosis of patients with gastric cancer.Methods:We retrospectively analyzed data from 444 gastric cancer patients who underwent gastrectomy at the First Affiliated Hospital of Sun Yat-sen University between January 1994 and December 2005.Preoperative SII was calculated.The Chi square test or Fisher's exact test was used to determine the relationship between preoperative SII and clinicopathologic characteristics.Overall survival (OS) rates were estimated using the Kaplan-Meier method,and the effect of SII on OS was analyzed using the Cox proportional hazards model.Receiver operating characteristic (ROC) curves were used to compare the predictive ability of SII,NLR,and PLR.Results:SII equal to or higher than 660 was significantly associated with old age,large tumor size,unfavorable Borrmann classification,advanced tumor invasion,lymph node metastasis,distant metastasis,advanced TNM stage,and high carcino-embryonic antigen level,high neutrophil-lymphocyte ratio,and high platelet-lymphocyte ratio (all P ＜ 0.05).High SII was significantly associated with unfavorable prognosis (P ＜ 0.001) and SII was an independent predictor for OS (P =0.015).Subgroups analysis further showed significant associations between high SII and short OS in stage Ⅰ,Ⅱ,Ⅲ subgroups (all P ＜ 0.05).SII was superior to NLR and PLR for predicting OS in patients with gastric cancer.Conclusion:Preoperative SII level is an independent prognostic factor for OS in patients with gastric cancer.