端粒植入对胃癌SGC-7901细胞生物学行为的影响

目的研究外源端粒片段植入对胃癌细胞生物学行为的影响，初步探讨端粒影响细胞生物学活性的作用机制。方法大规模制备含有端粒片段的质粒pSXneo-1．6-T2AG3，采用LipofectAMIN^TM2000介导的转染方式，将质粒转染胃癌细胞SGC-7901，检测细胞周期、细胞形态、细胞生长曲线和细胞周期相关基因表达的改变。结果端粒片段能够成功导入SGC-7901细胞，获得稳定的细胞株。端粒片段植入后细胞生长变慢，异型性减少，S期细胞减少，G0／G1和G2M期细胞比例增加，增殖指数减小，P21mRNA表达明显高于SGC-7901细胞（P〈0．05），caspase-3 mRNA在各组细胞的表达无显著差异（P〉0．05）。结论携带了1600bp端粒TTAGGG重复序列的真核表达载体pSXneo-1．6-T2AG3能够稳定转染至人胃癌SGC-7901细胞中，使细胞增殖减慢，P21 mRNA表达上调，但对caspase-3 mRNA表达无明显影响。

Effect of telomere seeding on the biological behaviors of gastric cancer cell SGC-7901

Objective To study the effect of telomere seeding on the biological behaviors of gastric cancer cell line and its mechanism. Methods The plasmid pSXneo-1.6-T2AG3, containing telomere fragment, was prepared in large scale and transfected into gastric cancer cell line SGC-7901 by LipofectAMINTM 2000. G418 was used to scan the positive clones and PCR was preformed to verify the stable seeding of the exogenous telomere in cell. MTT aassay and flow cytometry were used to determine the growth and cycle distribution of cells. The expression of cell cycle-related genes was detected by RT-PCR. Results Both pSXneo-1.6-T2AG3 eukaryonic expressing vector be inserted with telomere TTAGGG fragments and control vector were transfected into gastric cancer cell line SGC-7901 with LipofectamineTM 2000 and gain clones through G418 selection respectively, which were named as SGC-7901-telo and SGC-7901-neo. The cells were examined on DNA level by PCR to determine the correction of transfection. Flow cytometric analysis displayed an accumulation in G1M and G2M phase of cell cycle and an decreased percentage in S phase and proliferative index. Expression of p21 mRNA in 7901-telo cell line was increased (P<0.05)compared with in 7901-neo and 7901 cell line while the expression of caspase-3 had no significant change(P>0.05). Conclusion The pSX-T2AG3-neo eukaryonic expressing vector be inserted with 1600bp telomere TTAGGG fragments was successfully transfected into gastric cancer cell line SGC-7901 with the help of LipofectamineTM 2000. The seeding decreased malignant phenotypes of gastric cancer cell line and up-regulated the expression of p21, but the seeding did not distinctly influence on caspase3 mRNA expression.