吉林大学学报(医学版) ›› 2022, Vol. 48 ›› Issue (3): 657-667.doi: 10.13481/j.1671-587X.20220314

• 基础研究 • 上一篇    

沉默解旋酶BLM基因对结直肠癌细胞伊立替康化疗敏感性的影响及其机制

曹秋婷,韩竞春,张晓飞()   

  1. 大连大学附属新华医院肿瘤一科,辽宁 大连 116021
  • 收稿日期:2021-09-03 出版日期:2022-05-28 发布日期:2022-06-21
  • 通讯作者: 张晓飞 E-mail:274365378@qq.com
  • 作者简介:曹秋婷(1983-),女,山东省莒县人,主治医师,医学硕士,主要从事各种实体瘤的综合治疗方面的研究。
  • 基金资助:
    辽宁省科技厅自然基金指导计划项目(2019-ZD-0302);辽宁省大连市青年科技之星项目(2019RQ096)

Effect of silencing helicase BLM gene on chemotherapy sensitivity of irinotecan in colorectal cancer cells and its mechanism

Qiuting CAO,Jingchun HAN,Xiaofei ZHANG()   

  1. Department of Oncology,Affiliated Xinhua Hospital,Dalian University,Dalian 116021,China
  • Received:2021-09-03 Online:2022-05-28 Published:2022-06-21
  • Contact: Xiaofei ZHANG E-mail:274365378@qq.com

摘要: 目的

探讨沉默结直肠癌(CRC)细胞中布卢姆综合征解旋酶(BLM)基因表达对伊立替康(即CPT-11)化疗敏感性的影响,并阐明其相关作用机制。

方法

体外培养HT-29、Lovo、HCT-116、RKO和DLD1细胞,实时荧光定量PCR(RT-qPCR)和Western blotting法筛选高表达BLM mRNA和蛋白的RKO和DLD1细胞。将携带shRNA的慢病毒载体感染细胞以沉默RKO与DLD1细胞中的BLM表达,CCK-8法检测感染后各组CRC细胞存活率和CPT-11半数抑制浓度(IC50)值。将RKO或DLD1细胞分为LV-shNC组(感染LV-shNC的细胞)、CPT-11+LV-shNC组(CPT-11处理感染LV-shNC的细胞)和CPT-11+LV-shBLM组(CPT-11处理感染LV-shBLM的细胞)。流式细胞术检测不同细胞周期各组CRC细胞百分率,Western blotting法检测各组CRC细胞中兔抗B细胞淋巴瘤/白血病2关联死亡启动子(Bad)、裂解的含半胱氨酸的天冬氨酸蛋白水解酶3(cleaved caspase-3)、周期蛋白依赖性激酶4(CDK4)、周期蛋白依赖性激酶6(CDK6)和细胞周期依赖性蛋白激酶抑制因子1A(p21)蛋白表达水平,流式细胞术检测各组细胞凋亡率。构建异体移植瘤模型,检测各组小鼠肿瘤体积和肿瘤组织中BLM、K-i67及TUNEL的阳性表达率。

结果

与HT-29、Lovo或HCT-116细胞比较,RKO和DLD1细胞中BLM mRNA和蛋白表达水平均升高(P<0.05);与感染LV-shNC的RKO或DLD1细胞比较,感染LV-shBLM慢病毒后,RKO或DLD1细胞中BLM mRNA表达水平降低(P<0.05)。与LV-shNC组比较,CPT-11+LV-shNC组和CPT-11+LV-shBLM组细胞存活率和IC50值降低(P<0.05)。与LV-shNC组比较,CPT-11+LV-shNC组和CPT-11+LV-shBLM组G0/G1期和S期细胞百分率及细胞凋亡率均升高(P<0.05),而G2/M期细胞百分率降低(P<0.05),细胞中Cyclin D1,CDK4、CDK6和Bcl-2蛋白表达水平降低(P<0.05),而p21、Bax、Bad和cleaved caspase-3蛋白表达水平均升高(P<0.05);与CPT-11+LV-shNC组比较,CPT-11+LV-shBLM组G0/G1期和S期细胞百分率及细胞凋亡率均升高(P<0.05),而G2/M期细胞百分率降低(P<0.05),细胞中Cyclin D1、CDK4、CDK6和Bcl-2蛋白表达水平均明显降低(P<0.05),而p21、Bax、Bad和cleaved caspase-3蛋白表达水平均升高(P<0.05)。裸鼠移植瘤实验,与LV-shNC组比较,CPT-11+LV-shNC组和CPT-11+LV-shBLM组裸鼠肿瘤体积缩小(P<0.05),肿瘤组织中BLM及Ki-67的阳性表达率均降低(P<0.05),TUNEL阳性表达率升高(P<0.05);与CPT-11+LV-shNC组比较,CPT-11+LV-shBLM组裸鼠肿瘤体积缩小(P<0.05),肿瘤组织中BLM和Ki-67的阳性表达率均降低(P<0.05),TUNEL阳性表达率明显升高(P<0.05)。

结论

沉默CRC细胞中BLM表达可能通过抑制肿瘤细胞的周期进展,从而促进化疗药物CPT-11诱导的细胞凋亡,最终在体内外改善CRC细胞的化疗抵抗。

关键词: 结直肠肿瘤, 布卢姆综合征解旋酶, 细胞周期, 化疗敏感性, 细胞凋亡

Abstract: Objective

To investigate the effect of silencing the Bloom’s syndrome helicase(BLM) expression on the chemotherapy sensitivity of irinotecan (CPT-11) in the colorectal cancer (CRC) cells, and to elucidate its related mechanism.

Methods

The HT-29, Lovo, HCT-116, RKO, and DLD1 cells were cultured in vitro. The RKO and DLD1 cells with high expressions of BLM mRNA and protein were screened by real-time fluorescence quantitative PCR(RT-qPCR) and Western blotting methods. The cells were infected with lentivirus vector carrying shRNA to silence the expression of BLM in the RKO and DLD1 cells. The survival rates of the CRC cells and the half inhibitory concentration (IC50) values of CPT-11 in various groups after transfection were detected by CCK-8 assay. The RKO or DLD1 cells were divided into LV-shNC group (infected with LV-shNC), CPT-11+LV-shNC group ( infected with LV-shNC and treated with CPT-11) and CPT-11+LV-shBLM group (infected with LV-shBLM and treated with CPT-11). The percentages of the cells in various groups at different cell cycles were detected by flow cytometry. The expression levels of BCL2 associated death promoter(Bad),cleaved of cysteinyl aspartate specific proteinase(cleaved caspase-3), cyclin-dependent protein kinase 4(CDK4),cyclin-dependent protein kinase 6 (CDK6),and cyclin-dependent kinase inhibitor 1A(p21) proteins in the CRC cells in various groups were detected by Western blotting method; the apoptotic rates of the cells in various groups were detected by flow cytometry.The tumor volume and positive expression rates of BLM, Ki-67,and TUNEL in tumor tissue of the CRC-bearing mice were detected by constructing the allograft tumor model.

Results

Compared with the HT-29, Lovo or HCT-116 cells, the expression levels of BLM mRNA and protein in the RKO and DLD1 cells were increased (P<0.05);compared with RKO or DLD1 cells infected with LV-shNC, the expression levels of BLM mRNA in the RKO or DLD1 cells infected with LV-shBLM lentivirus were decreased(P<0.05). Compared with LV-shNC group, the survival rates and IC50 values of the cells in CPT-11+LV-shNC group and CPT-11+LV-shBLM group were decreased(P<0.05).Compared with LV-shNC group, the percentages of the cells at G0/ G1 phase and S phase and the apoptotic rates of the cells in CPT-11+LV-shNC group and CPT-11+LV-shBLM group were increased (P<0.05), while the percentages of the cells at G2 / M phase were decreased (P<0.05),and the expression levels of Cyclin D1, CDK4, CDK6 and Bcl-2 proteins were decreased(P<0.05), while the expression levels of p21, Bax, Bad,and cleaved caspase-3 proteins were increased (P<0.05);compared with CPT-11+LV-shNC group, the percentages of the cells at G0/G1 phase and S phase and the apoptotic rate of the cells in CPT-11+LV-shBLM group were increased (P<0.05), while the percentage of the cells at G2/M phase was decreased (P<0.05),and the expression levels of Cyclin D1,CDK4, CDK6,and Bcl-2 proteins were decreased(P<0.05), while the expression levels of p21, Bax, Bad,and cleaved caspase-3 proteins were increased (P<0.05). The nude mice transplanted tumor experiment results showed that compared with LV- shNC group, the tumor volumes of the nude mice and the positive expression rates of BLM and Ki-67 in the cells in CPT-11+LV-shNC group and CPT-11+LV-shBLM group were decreased (P<0.05), and the positive expression rates of TUNEL were increased(P<0.05); compared with CPT-11+LV-shNC group, the tumor volume of the nude mice in CPT-11+LV -shBLM group was decreased (P<0.05), and the positive expression rates of BLM and Ki-67 in tumor tissue were decreased (P<0.05), and the positive expression rate of TUNEL was increased(P<0.05).

Conclusion

Silencing BLM expression in the CRC cells may promote CPT-11-induced apoptosis by inhibiting the cycle progression of tumor cells, and ultimately improve chemotherapy resistance of CRC cells in vivo and in vitro.

Key words: Colorectal neoplasms, Bloom’s syndrome helicase, Cell cycle, Chemosensitivity, Apoptosis

中图分类号: 

  • R735.3