Objective:To investigate the effect of ribonucleotide reductase regulatory subunit M2 (RRM2) on the malignant biological behavior and aerobic glycolysis of gastric cancer cells by regulating cyclin-dependent kinase (CDK) 1.Methods:Human gastric cancer MKN-45 cells were divided into si-NC group (transfected with blank fragment) , CoCl 2+si-NC group (hypoxia control transfected with blank fragment) , CoCl 2+si-RRM2 group (hypoxia with RRM2 silencing) , CoCl 2+si-RRM2+pcDNA3.1 NC group (hypoxia with RRM2 silencing and blank vector) and CoCl 2+si-RRM2+pcDNA3.1 CDK1 group (hypoxia with RRM2 silencing and CDK1 overexpression) . The mRNA relative expression levels of RRM2 and CDK1 were analyzed by real time fluorescent quantitative reverse transcription PCR. Co-immunoprecipitation (CoIP) was used to analyze the interaction between RRM2 and CDK1 protein. MTT assay was used to analyze the proliferation activity of cells. The cell migration distance was detected by cell scratch assay. Cell apoptosis was detected by flow cytometry. Adenosine triphosphate (ATP) and glucose kit were used to detect ATP production and glucose consumption. The protein expressions of ENO1, RRM2, HK2, PKM2, GLUT1 and p-CDK1/CDK1 were detected by Western blotting. Results:Real time fluorescent quantitative reverse transcription PCR results showed that the relative expression levels of CDK1 mRNA in si-NC group, CoCl 2+si-NC group and CoCl 2+si-RRM2 group were 1.01±0.15, 1.30±0.06 and 0.51±0.18, and the relative expression levels of RRM2 mRNA were 1.03±0.32, 1.59±0.28 and 0.44±0.17, respectively, and there were statistically significant differences ( F=25.52, P=0.001; F=14.47, P=0.005) . The mRNA expressions of RRM2 and CDK1 in CoCl 2+si-NC group were higher than those in si-NC group. Compared with the si-NC group and the CoCl 2+si-NC group, the mRNA expressions of RRM2 and CDK1 were lower in the CoCl 2+si-RRM2 group (all P<0.05) . CoIP results showed that there was interaction between RRM2 and CDK1. MTT assay, cell scratch assay and flow cytometry showed that the cell proliferation activity of si-NC group, CoCl 2+si-NC group, CoCl 2+si-RRM2 group, CoCl 2+si-RRM2+pcDNA3.1 NC group and CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were 1.04±0.01, 1.18±0.04, 0.84±0.03, 0.81±0.03 and 0.93±0.05, respectively. The cell migration distances were (301.83±2.75) , (369.67±0.76) , (176.50±6.38) , (175.83±3.69) , (254.17±1.61) μm, respectively. The apoptosis rates were 8.05%±0.21%, 5.75%± 0.20%, 28.28%±0.04%, 30.18%±1.51% and 17.79%±0.22%, respectively, all with statistically significant differences ( F=73.82, P<0.001; F=1 600.01, P<0.001; F=787.15, P<0.001) . Compared with the si-NC group and CoCl 2+si-NC group, the proliferation and migration ability of cells in the CoCl 2+si-RRM2 group, CoCl 2+si-RRM2+pcDNA3.1 NC group and CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were weaker, and the apoptosis rates were higher (all P<0.05) . Compared with the CoCl 2+si-RRM2+pcDNA3.1 NC group, the proliferation and migration ability of cells in the CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were stronger, and the apoptosis rate was lower (all P<0.05) . The results of ATP and glucose detection showed that there were statistically significant differences in the amount of ATP production and glucose consumption among the above five groups ( F=12.53, P<0.001; F=19.21, P<0.001) . Compared with the si-NC group, the glucose consumption of cells was lower in the CoCl 2+si-RRM2+pcDNA3.1 CDK1 group ( P<0.05) . Compared with the CoCl 2+si-NC group, the ATP production and glucose consumption of cells in the CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were lower (both P<0.05) . Compared with the CoCl 2+si-RRM2+pcDNA3.1 NC group, the ATP production and glucose consumption of the CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were higher (both P<0.05) . Western blotting showed that there were statistically significant differences in the protein expressions of ENO1, RRM2, HK2, PKM2, GLUT1, and p-CDK1/CDK1 among the above five groups (all P<0.001) . Compared with the si-NC group and the CoCl 2+si-NC group, the protein expressions of ENO1, RRM2, HK2, PKM2, GLUT1 and p-CDK1/CDK1 in the CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were lower (all P<0.05) . Compared with the CoCl 2+si-RRM2+pcDNA3.1 NC group, the protein expressions of ENO1, RRM2, PKM2, GLUT1 and p-CDK1/CDK1 in the CoCl 2+si-RRM2+pcDNA3.1 CDK1 group were higher (all P<0.05) . Conclusions:Silencing RRM2 can inhibit the malignant biological behavior of gastric cancer cells and the occurrence of aerobic glycolysis by regulating CDK1.

Background/Aims: The increased mortality of gastric cancer (GC) is mainly attributed to the development of chemoresistance. Circular RNAs, as the novel type of biomarkers in GC, have attracted wide attention. The purpose of this study was to investigate the functional role of circ_0081143 in GC with doxorubicin (DR) resistance and its potential action mechanism. Methods: The expression of circ_0081143, miR-129-2-3p and YES proto-oncogene 1 (YES1) in GC tissues and cells was measured by quantitative real-time polymerase chain reaction. The half maximal inhibitory concentration value was calculated based on the MTT cell viability assay. Cell proliferation and apoptosis were monitored by MTT and flow cytometry assays. Transwell assays were employed to check cell migration and invasion. The protein levels of YES1 and apoptosis-related proteins were detected by western blotting. The interaction between miR-129-2-3p and circ_0081143 or YES1 was verified by dual-luciferase reporter and pull-down assays. A tumorigenicity assay was conducted to verify the role of circ_0081143 in vivo. Results: Circ_0081143 was highly expressed in DR-resistant GC tumor tissues and cells. Depletion of circ_0081143 reduced DR resistance and inhibited DR-resistant GC cell proliferation, migration and invasion. Circ_0081143 targeted miR-129-2-3p and inhibited the role of miR-129-2-3p. In addition, YES1 was a target of miR-129-2-3p, and its function was suppressed by miR-129-2-3p. Importantly, circ_0081143 positively modulated the expression of YES1 through mediating miR-129-2-3p. Circ_0081143 knockdown weakened the DR-resistant GC tumor growth in vivo. Conclusions Circ_0081143 knockdown weakened DR resistance and blocked the development of DR-resistant GC by regulating the miR-129-2-3p/YES1 axis. Our data suggest that circ_0081143 is a promising target for the treatment of GC with DR resistance.

Objective To investigate the therapeutic efficacy of laparoscopic surgery for treatment of the patients with advanced gastric cancer.Methods A total of 120 patients with advanced gastric cancer treated by D2 radical resection of distal gastric cancer from January 2015 to January 2017 in Affiliated Hospital of Guangdong Medical University were retrospectively analyzed.According to the method of operation,the patients were divided into laparoscopic group (60 cases) and laparotomy group (60 cases).The operation-related indexes,operation curative effect indexes and postoperative recovery were compared between the two groups by using x 2 test and t test.Results The operation time of the laparoscopic group was longer than that of the laparotomy group [(197±21) min vs.(178±23) min,t =4.759,P ＜ 0.001].Some parameters in the laparoscopic group were lower than those in the laparotomy group (all P ＜ 0.05),including intraoperative blood loss [(111±30) ml vs.(221±52) ml,t =14.103],the length of the surgical incision[(6.1±1.3) cm vs.(17.3±3.2) cm,t =25.117],postoperative anal evacuation time [(90±14) h vs.(110±18) h,t =6.983],the postoperative bed-out time [(2.9±0.8) d vs.(4.8±1.4) d,t =9.127],the postoperative liquid dietary intake time [(4.3±0.9) d vs.(5.7±1.2) d,t =7.230],and hospital stay time [(13.2±2.5) d vs.(15.5±3.2) d t =4.387].There were no statistical differences in the number of removed lymph nodes,the number of first-site removed lymph nodes,the number of second-site removed lymph nodes,the distance from the distal margin to the tumor,and the distance from the proximal margin to the tumor (t values 1.351,0.912,1.240,0.876,and 0.840 respectively,all P ＞ 0.05);The incidence of operative complications in the laparoscopic group was lower than that in the laparotomy group [6.67 ％ (4/60) vs.20.00 ％ (12/60),X 2 =4.615,P =0.032].Conclusion Laparoscopic surgery in the treatment of advanced gastric cancer patients has a favorable effect,with reliable results,less trauma,postoperative recovery and fewer complications.

OBJECTIVETo evaluate the association of early diarrhea and fecal volume with anastomotic leakage after low anterior resection (LAR) of rectal cancer.

METHODSClinical data of 541 patients with rectal cancer undergoing LAR at The Affiliated Hospital of Guangdong Medical College between January 2007 and January 2017 were analyzed retrospectively. Early postoperative diarrhea was defined as at least one occurrence of more than 50 ml watery stool or at least four times defecation per day within 7 days after surgery. The volume of fecal discharge from the transanal drain was measured at daily intervals for 3 days after surgery. Association of early diarrhea and anastomotic leakage was analyzed using logistic regression model. The accuracy of fecal volume in predicting anastomotic leakage was evaluated using receiver operating characteristics (ROC) curve.

RESULTSThere were 319 males and 222 females with mean age of 59.3 years. Early postoperative diarrhea occurred in 99(18.3%) patients, and 41(7.6%) patients developed anastomotic leakage. The incidence of anastomodc leakage in patients with early diarrhea was significantly higher as compared to those without early diarrhea (15.2% vs. 5.9%, P=0.000). Multivariate analysis revealed that early diarrhea (OR=33.940, 95%CI: 8.423 to 89.240) and the distance between the tumor and the anal verge less than 7 cm (OR=13.085, 95%CI: 2.117 to 44.556) were independent risk factors for anastomotic leakage, while the presence of a transanal tube was an independent protective factor (OR=0.474, 95%CI: 0.122 to 0.881). The total fecal volume for 3 days after surgery was calculated in 162 patients with a transanal tube. The median fecal volume was 210 (100 to 4360) ml and 60 (0 to 480) ml in patients with and without anastomotic leakage respectively(P=0.000). ROC curve showed that the cut-off value of fecal volume for anastomotic leakage was 110 ml and the area under the curve was 0.824 with a high sensitivity of 85.7% and specificity of 81.3%.

CONCLUSIONSEarly postoperative diarrhea after LAR procedure of rectal cancer may be an early predictor of anastomotic leakage, and fecal volume for 3 days after surgery ≥110 ml can accurately predict anastomotic leakage. Active prevention and management of early postoperative diarrhea may reduce the risk of anastomotic leakage.

Objective To evaluate the use of Thymidine Kinase 1(TK1)in serum as proliferating tumor marker for gas-tric carcinoma and monitoring marker for the response to operation. Methods Serum level of TK1 expression were de-tected with sensitive chemiluminescence dot-blot assay in were available to detect the level of serum TK1 in 35 cases of normal healthy subject and 68 cases of patients with gastric carcinoma, compared with 43 cases of patients with gastric carcinoma pre-and post-operation. Results The level of serum TK1 were elevated in all subgroups of patients with gastric carcinoma compared to the normal healthy subject(P<0.01),serum TK1 was correlated with TNM stage and histological grade,and not with sex and age; the serum TK1 level in stage Ⅳwas higher in comparison with stage Ⅲ,in stage Ⅲit was higher than that in stage II, in stage IIit was higher than that in stage Ⅰ, and in stage Ⅰit was higher than that in normal healthy subject (P<0.01-0.05); Being lower in the well differentiated and moderately dif-ferentiated than the poorly differentiated (P<0.01-0.05), the level of serum TK1 was higher in the cases of poorly differentiated adenocarcinoma, signet ring cell carcinoma and mucoid adenocarcinoma than those in the cases of well differentiated and moderately differentiated adenocarcinoma (P<0.05), the serum TK1 levels remarkably reduced in patients with gastric carcinoma after operation(P<0.01). Conclusion Detection the level of serum TK1 may be larger clini-cal value for cancer diagnosis,predict disease progression and the curative effect in patients with gastric carcinoma.