hMMS2基因对结肠癌细胞耐药逆转的影响

Roles of hMMS2 gene in reversing the oxaliplatin tolerance of human colon carcinoma cells

为探讨hMMS2(Human methyl methanesulfonate sensitive mutant 2)基因对人结肠癌细胞耐药逆转的影响,文章以人高分化耐奥沙利铂结肠癌细胞(THC8307/L-OHP)为实验材料,采用脂质体-质粒转染技术构建了带有干扰目的基因hMMS2的miRNA片段并携带绿色荧光蛋白标记重组质粒(pcDNA6.2-GW/EmGFP-miR-MMS2)的细胞系,通过实时荧光定量PCR(qRT-PCR)和免疫荧光技术(Immunostaining technique)检测该细胞系的干扰效率。选择hMMS2低表达具有统计学意义的上述细胞系作为实验组细胞,同时将未曾作过处理的THC8307/L-OHP细胞作为空白对照组,转染绿色荧光蛋白空质粒(pcDNA6.2-GW/EmGFP-miR)的THC8307/L-OHP细胞作为阴性对照组,以噻唑蓝比色分析实验(MTT colorimetric analysis assay)、克隆形成实验(Colony formation assay)对3组细胞的存活率和克隆形成率进行检测,结果显示:实验组细胞的奥沙利铂半数抑制浓度(Half inhibition concentration,IC50)、耐药指数(Resistance index,RI)及克隆形成率(Colony-forming efficiency,CFE)均比对照组细胞明显降低(P<0.05),而相对逆转率(Relative reverse efficiency,RRE)增高(P<0.05),提示实验组细胞增殖能力减弱;以罗丹明123实验(Rhodamine 123 assay)结合倒置荧光显微镜、流式细胞仪检测技术等观测细胞的凋亡变化,结果显示,实验组细胞的凋亡率较对照组细胞显著增高(P<0.05);两对照(空白、阴性)组间并无细胞增殖或凋亡的显著性差异。研究结果提示:下调hMMS2基因表达可逆转人高分化耐奥沙利铂结肠癌细胞对L-OHP的耐药性并促进结肠癌细胞的凋亡。

In this study,the roles of hMMS2 （human methyl methanesulfonate sensitive mutant 2） gene encoding the human ubiquitin-conjugating enzyme E2 variant 2 in the drug resistance in human colon carcinoma were investigated by using a well-differentiated human colorectal carcinoma L-OHP-resistant cell line,THC8307/L-OHP.THC8307/L-OHP cells were transfected via liposome along with plasmid pcDNA6.2-GW/EmGFP-miR-MMS2 expressing both miRNA against hMMS2 and GFP,followed by real-time fluorescent quantitative PCR and immunofluorescence to select stable transfectants with significantly reduced hMMS2 expression.Compared with untransfected or pcDNA6.2-GW/EmGFP vector-transfected cells,the hMMS2-depleted cells displayed significantly （P＜0.05） reduced half inhibition concentration（IC50） resistance index （RI） and colony-forming efficiency （CFE） upon treatment with oxaliplatin （L-OHP）,while its relative reverse efficiency（RRE） was significantly higher （P＜0.05） than the control cells,indicating compromised ability of cell proliferation.Indeed,Rhodamine 123 staining and flow cytometry analyses revealed an increased rate of apoptosis in hMMS2-depleted cells while no difference in cell proliferation or apoptosis was observed between the two control cell lines.The above observations collectively indicate that suppression of hMMS2 reverses L-OHP tolerance in differentiated human colorectal carcinoma cells by promoting apoptosis.