目的:探讨细胞周期蛋白D1（cyclin D1）的编码基因CCND1 miR-340介导的逆转结直肠癌细胞对5-氟尿嘧啶（5-Fu）耐药的机制。方法：采用瞬时转染技术将结直肠癌细胞HCT116、SW480株分别转染si-CCND1和miR340-mimic。应用MTT法检测转染后的结直肠癌细胞对5-Fu敏感性的变化，应用双荧光素酶试验验证CCND1对miR340参与的影响结直肠癌细胞对5-Fu敏感性的影响。结果：瞬时转染siCCND1和过表达miR-340后，结直肠癌HCT116和SW480细胞的IC50值均显著低于对照组（10，10 vs 20 μmol/L和20，20 vs 40 μmol/L，均P<0.05）。共转染CCND1 3′UTR野生质粒和miR-340 inhibitor的结直肠癌HCT116和SW48细胞荧光素酶的活性显著高于共转染空载体和mimic细胞(P<0.01）。结论：CCND1作为不良因子通过抑制miR340的表达进而发挥增加结直肠癌细胞对5-Fu耐药的作用。

Objective:To investigate the mechanism of coding gene of cell cyclin D1(CCND1) participating in miR-340-induced inhibition of chemotherapy resistance of colorectal cancer cells to 5-fluorouracil (5-Fu). Methods: Colorectal cancer HCT115 and SW480 cell lines were transfected with si-CCND1and miR340-mimic respectively by transient transfection technology. The sensitivity of cancer cells to 5-Fu after transfection was observed with MTT. The effect of CCND1 on miR-340 mediated suppression of chemotherapy resistance of cancer cells to 5-Fu was validated by double luciferase test. Results: After transient transfection with siCCND1 or over-expression of miR-340, the IC50 values of HCT116 and SW480 cell lines were significantly lower than that of control group \[CCND1 silencing: 10, 10 vs 20 μmol/L; miR-340 over-expressing: 20, 20 vs 40 μmol/L; all P<0.05). After co-transfection with CCND1 3′UTR wild plasmid and miR-340 inhibitor, the luciferase reporter activity in HCT 116 and SW480 cells were significantly higher than that of empty plasmid transfection group or mimic transfection group (P<0.01). Conclusion: CCND1, as an unfavorable factor, enhances the chemo-resistance of colorectal cancer cells to 5-FU by inhibiting the expression of miR-340.

广东省自然科学基金资助项目（No.2015A030311005）