BTG1 might be employed as a biomarker for carcinogenesis and a target for gene therapy in colorectal cancers

// Shuang Zhao 1 , Shu-rui Chen 2 , Xue-feng Yang 1 , Dao-fu Shen 1 , Yasuo Takano 3 , Rong-jian Su 4 , Hua-chuan Zheng 1, 4 1 Cancer Center, Key Laboratory of Brain and Spinal Cord Injury of Liaoning Province, and Animal Center, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, China 2 Department of Science and Technology, Jinzhou Medical University, Jinzhou, China 3 School of Health Science, Tokyo University of Technology, Nishi-Kamata, Ohta-ku, Tokyo, Japan 4 Life Science Institute of Jinzhou Medical University, Jinzhou, China Correspondence to: Hua-chuan Zheng, email: zheng_huachuan@hotmail.com Keywords: colorectal cancer, BTG1, carcinogenesis, aggressive phenotypes, gene therapy Received: April 02, 2016     Accepted: June 03, 2016     Published: July 18, 2016 ABSTRACT Here, BTG1 overexpression inhibited proliferation, induced differentiation, autophagy, and apoptosis in colorectal cancer cells (p<0.05). BTG1 overexpression reduced mitochondrial membrane potential and caused senescence in HCT-116 transfectants (p<0.05). BTG1-induced G 2 arrest might be related to Cyclin B1 and Cdc25B hypoexpression in HCT-15 transfectants, while G 1 arrest in HCT-116 transfectants overexpressing p21 and p27. BTG1 overexpression decreased the expression of Bcl-2, Bcl-xL, XIAP, Akt1 or survivin and increased the expression of Bax or p53 in colorectal cancer cells. BTG1-induced autophagy was dependent on Beclin-1 expression. BTG1 overexpression might weaken β-catenin pathway in colorectal cancer cells. The chemosensitivity of BTG1 transfectants to paclitaxel, cisplatin, MG132 or SAHA was positively correlated with its apoptotic induction. There was a lower expression level of BTG1 in cancer than matched non-neoplastic mucosa by RT-PCR (p<0.05), while versa for Western blot and immunohistochemical data (p<0.05). BTG1 overexpression significantly suppressed the growth of HCT-15 and HCT-116 via inhibiting proliferation, inducing apoptosis and autophagy in nude mice. Up-regulated BTG1 expression plays an important role in colorectal carcinogenesis as a potential biomarker. BTG1 expression might reverse aggressive phenotypes, so it might be employed as a target of gene therapy for colorectal cancer.