The roles of BTG3 expression in gastric cancer: a potential marker for carcinogenesis and a target molecule for gene therapy.

BTG (B-cell translocation gene) can inhibit cell proliferation, metastasis and angiogenesis, cell cycle progression, and induce differentiation in various cells. Here, we found that BTG3 overexpression inhibited proliferation, induced S/G2 arrest, differentiation, autophagy, apoptosis, suppressed migration and invasion in MKN28 and MGC803 cells (p < 0.05). BTG3 transfectants showed a higher mRNA expression of p27, Bax, 14-3-3, Caspase-3, Caspase-9, Beclin 1, NF-κB, IL-1, -2, -4, -10 and -17, but a lower mRNA expression of p21, MMP-9 and VEGF than the control and mock (p < 0.05). At protein level, BTG3 overexpression increased the expression of CDK4, AIF, LC-3B, Beclin 1 and p38 (p < 0.05), but decreased the expression of p21 and β-catenin in both transfectants (p < 0.05). After treated with cisplatin, MG132, paclitaxel and SAHA, both BTG3 transfectants showed lower viability and higher apoptosis than the control in both time- and dose-dependent manners (p < 0.05). BTG3 expression was restored after 5-aza-2'-deoxycytidine or MG132 treatment in gastric cancer cells. BTG3 expression was decreased in gastric cancer in comparison to the adjacent mucosa (p < 0.05), and positively correlated with venous invasion and dedifferentiation of cancer (p < 0.05). It was suggested that BTG3 expression might contribute to gastric carcinogenesis. BTG3 overexpression might reverse the aggressive phenotypes and be employed as a potential target for gene therapy of gastric cancer.