Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Continuous and low-energy 125I seed irradiation changes DNA methyltransferases expression patterns and inhibits pancreatic cancer tumor growth | Ma et al. Journal of Experimental Clinical Cancer Research 2011 30 35 http content 30 1 35 Journal of Experimental Clinical Cancer Research RESEARCH Open Access Continuous and low-energy 125I seed irradiation changes DNA methyltransferases expression patterns and inhibits pancreatic cancer tumor growth Jian-xia Ma Zhen-dong Jin Pei-ren Si Yan Liu Zheng Lu Hong-yu Wu Xue Pan Luo-wei Wang Yan-fang Gong Jun Gao and Li Zhao-shen Abstract Background Iodine 125 125I seed irradiation is an effective treatment for unresectable pancreatic cancers. However the radiobiological mechanisms underlying brachytherapy remain unclear. Therefore we investigated the influence of continuous and low-energy 125I irradiation on apoptosis expression of DNA methyltransferases DNMTs and cell growth in pancreatic cancers. Materials and methods For in vitro 125I seed irradiation SW-1990 cells were divided into three groups control 0 Gy 2 Gy and 4 Gy. To create an animal model of pancreatic cancer the SW 1990 cells were surgically implanted into the mouse pancreas. At 10 d post-implantation the 30 mice with pancreatic cancer underwent 125I seed implantation and were separated into three groups 0 Gy 2 Gy and 4 Gy group. At 48 or 72 h after irradiation apoptosis was detected by flow cytometry changes in DNMTs mRNA and protein expression were assessed by real-time PCR and western blotting analysis respectively. At 28 d after 125I seed implantation in vivo apoptosis was evaluated with TUNEL staining while DNMTs protein expression was detected with immunohistochemical staining. The tumor volume was measured 0 and 28 d after 125I seed implantation. Results 125I seed irradiation induced significant apoptosis especially at 4 Gy. DNMT1 and DNMT3b mRNA and protein expression were substantially higher in the 2 Gy group than in the control group. Conversely the 4 Gy cell group exhibited significantly decreased DNMT3b mRNA and protein expression relative to the control group. There were .
