Objective To explore the relationship between Beclin-1 and the development of pancreatic ductal adenocarcinoma (PDAC). Methods ① Twenty-five PDAC specimens and 20 matched adjacent normal pancreatic tissues were obtained after radical surgery between April 2009 and November 2009 in West China Hospital of Sichuan University. Beclin-1 mRNA and protein expressions were examined by using real-time PCR and immunohistochemistry, respectively. Correlations between expressions of Beclin-1 protein with clinical data of PDAC patients were evaluated. ② PDAC cells were divided into 2 groups, cells of transfection group were transfected with PLenO-WPI-Beclin-1 vector, and cells of non-transfection group didn’t transfected with PLenO-WPI-Beclin-1 vector. Expressions levels of Beclin-1 mRNA in the 2 groups were detected by real-time PCR at 24 hours and 48 hours after transfection. ③ PDAC cells were divided into 3 groups, cells of transfection group were transfected with PLenO-WPI-Beclin-1 vector, cells of empty vector group transfected with PLenO-WPI, cells of blank control group didn’t accepted any vector. OD value was detected by MTT once a day during 1–7 days after transfection. Results ① Expression levels of Beclin-1 mRNA and its protein were significantly lower in PDAC tissue than those of adjacent normal pancreatic tissues (P<0.05). Increased Beclin-1 expression was associated with early TNM stage of Ⅰ and Ⅱ(P<0.05) and negative distant metastasis (P=0.011). ② At the same time point of 24 hours and 48 hours after transfection, the expression levels of Beclin-1 mRNA were higher in transfection group than those of non-transfection group (P<0.05). ③ MTT assay showed that PANC-1 cell proliferation ability was lower in the transfection group compared to the blank control group and empty vector groups in vitro on day 4–7 after transfection (P<0.05), but there was no significant in the cell proliferation ability among the 3 groups on day 1, 2, and 3 (P>0.05). Conclusions Down regulation of Beclin-1 and autophagy inhibition play an important role in the tumorigenesis and development of PDAC. Activating autophagy via overexpression of Beclin-1 may be a potential treatment for some PDACs and warrants further investigation.
ObjectiveTo systematically evaluate relationship between expression of autophagy-related protein Beclin-1 in gastric cancer and its clinicopathologic features and its clinical significances.MethodsThe researches on the expression and significance of Beclin-1 protein in the gastric tumor tissues published from the database establishment to June 1, 2018 in the Cochrane Library, Springer Link, Web of Science, Embase, PubMed, CNKI, Wanfang, VIP, and other databases were searched. Two researchers independently screened and evaluated the literatures, extracted the relevant data, and conducted the meta-analysis using the Review Manager 5.3 and Stata 15.0 software.ResultsFinally, 10 articles were included, and there were 1 402 patients with gastric cancer. The meta-analysis showed that the positive rate of Beclin1 protein expression in the gastric cancer tissues was significantly lower than that in the non-gastric cancer tissues [OR=0.30, 95% CI (0.13, 0.72), P=0.007], which in the patients with TNM stage Ⅲ/Ⅳ and distant metastatic gastric cancer were significantly lower than those in the patients with stage Ⅰ/Ⅱ [OR=1.82, 95% CI (1.03, 3.20), P=0.04] and without distant metastasis [OR=0.36, 95% CI (0.20, 0.63), P=0.000 4], which were not associated with the gender, age, tumor size, lymph node metastasis, serosa invasion, and tumor differentiation degree of gastric cancer patients (P>0.05). For the studies of existed heterogeneity, further the subgroup analysis showed that the positive expression rate of Beclin-1 protein in the gastric cancer tissues was significantly lower than that in the non-gastric cancer tissues [OR=0.19, 95% CI (0.13, 0.29), P<0.000 01], which in the patients with lymph node metastasis, invasion of serosa, and poorly differentiated gastric cancer were significantly lower than those in the non-lymph node metastasis [OR=0.35, 95% CI (0.22, 0.57), P<0.000 1], non-invasion of serosa [OR=0.56, 95% CI (0.33, 0.94), P=0.03], and moderately/highly differentiated gastric cancer tissues [OR=0.29, 95% CI (0.20, 0.43), P<0.000 01].ConclusionsLow expression of Beclin-1 in gastric cancer tissues is related to stage and distant metastasis of gastric cancer. It is suggested that it might not only be an important cause of gastric cancer, but also play a regulatory role in progress of gastric cancer.