Effects of small interfering RNA interference of connexin 37 on subcutaneous gastric tumours in mice.

The present study aimed to investigate the effects of small interfering (si)RNA interference of connexin 37 (Cx37) on subcutaneous gastric tumours in mice. Constructed lentiviruses carrying siRNA against Cx37 significantly knocked down Cx37 mRNA and protein expression in vitro. A total of 60 mice with gastric cancer were randomly divided into the Cx37 siRNA group, the mock-siRNA group and the control group. Cx37 siRNA, mock-siRNA and saline were separately injected (with the lentiviruses transfected into the gastric cancer cells). Following six weeks, the Cx37 mRNA expression, Cx37 protein expression and tumor apoptosis were detected using semiquantitative reverse transcription-polymerase chain reaction, western blot analysis and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling, respectively. Six weeks following lentiviral transfection, the Cx37 mRNA levels in the Cx37 siRNA group, mock-siRNA group and saline group decreased to 42, 63 and 67%, respectively (P<0.05). The mock-siRNA group demonstrated no significant change in Cx37 levels compared with the control group. Western blot analysis revealed lower Cx37 protein levels in the Cx37-RNA1 group than in the other groups (0.21 +/- 0.07 vs. 0.65 +/- 0.06 vs. 0.54 +/- 0.07), and that the apoptotic index of the Cx37-RNAi group was higher than those of the mock-siRNA and control groups (19.7 +/- 5.1 vs. 9.8 +/- 6.4 vs. 10.5 +/- 7.2%, 11.1 +/- 6.9; P<0.05). In conclusion, it was demonstrated that Cx37 siRNA is correlated with gastric cancer. Interference of Cx37 effectively reduces Cx37 mRNA and protein expression and promotes tumour apoptosis.