原蛋白转变酶2基因表达对肿瘤细胞增殖的影响

Effect of proprotein convertase 2 gene expression on the proliferation of tumor cells

目的探讨原蛋白转变酶2基因(proprotein convertase,PC2)对不同肿瘤细胞增殖的影响,为肿瘤治疗提供新的研究方向。方法 PC2重组质粒pcDNA3.1-PC2单独或与其分子伴侣7B2重组质粒pcDNA3.1-7B2混合转染小鼠乳腺癌细胞4T1、人肝癌细胞HepG2、小鼠黑色素瘤细胞B16、人肺癌细胞A549、人乳腺癌细胞MCF-7和小鼠肥大细胞瘤细胞P815,以pcDNA3.1(+)空载体为对照,通过PC2酶活性测定法、Western blot检测野生型和转染后的4T1细胞的PC2酶活性和表达,MTT法检测肿瘤细胞增殖率的变化。通过DAPI染色检测转基因细胞和TUNEL染色检测荷瘤模型瘤组织中癌细胞的凋亡情况。结果 1∶1比例的PC2∶7B2共转染显示了在4T1细胞中的最高PC2活性和表达,在荷瘤小鼠瘤组织中显示明显的凋亡现象。该共转染对4T1、HepG2、B16、A549和MCF-7细胞半数抑制剂量分别为128.3、97.8、137.3、51.5、214.3μg/m L,呈剂量依赖性,P815细胞的抑制率与基因剂量之间没有关系。结论 PC2上调可以抑制多种肿瘤细胞的增殖,呈现凋亡现象。

Objective To study the effect of proprotein convertase 2 （ PC2） on the proliferation of different tumor cells, and provide a new research direction for tumor therapy. Methods The PC2 recombinant plasmid pcDNA3.1-PC2 with or without its molecular chaperone recombinant plasmid pcDNA3.1-7B2 were transfected into mouse breast cancer 4T1 cells, human liver cancer HepG2 cells, mouse melanoma B16 cells, human lung cancer A549 cells, human breast cancer MCF-7 cells and mouse mastocytoma P815 cells, respectively. The mock pcDNA3.1 plasmid was used as a control. The expression and activity of PC2 was detected by western blot. The proliferation of tumor cells was measured by MTT. Cell apoptosis in transfected cells and tumor tissues was analyzed by DAPI and TUNEL staining, respectively. Results The highest PC2 enzyme activity and expression was observed in 4T1 cells when the rate of co-transfection of P2：7B2 was 1：1, which also induced more cell apoptosis in the breast tumor tissues. Meantime, the co-transfection of PC2 and 7B2 inhibited the proliferation of 4T1 cells, HepG2 cells, B16 cells, A549 cells and MCF-7 cells, but not P815 cells, in a dose-dependent manner, and their IC50 values were 128. 3, 97. 8, 137.3, 51.5 and 214.3μg/ml. Conclusion The up-regulation of PC2 expression can inhibit the proliferation of tumor cells by induction of cell apoptosis.