Cao Dongxing, Qin Shaolan, Mu Yifei, Zhong Ming
Department of Gastrointestinal Surgery, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200127, P.R. China.
Oncol Lett. 2017 Apr;13(4):2471-2476. doi: 10.3892/ol.2017.5741. Epub 2017 Feb 14.
The role of multidrug resistance associated protein 1 (MRP1) in the multidrug resistance (MDR) of colorectal cancer (CRC) remains unclear. The present study aimed to investigate the effect of MRP1 in MDR CRC and its therapeutic potential for the treatment of patients with this disease. The human MDR CRC cell lines HCT-8 and Colo205 were established through stable exposure to 5-florouracil (5-FU) over a 5-month period. MRP1 was knocked-down in MDR CRC cells through the transfection of short hairpin RNA targeting MRP1 (shMRP1). Western blotting was performed to assess the efficiency of this silencing. MTT and apoptosis assays were conducted to detect cell viability and apoptosis, respectively. Compared with their parental cells, HCT-8/5-FU and Colo205/5-FU cells were 23.1 and 15.8 times more resistant to 5-FU, and 17.2 and 20.9 times more resistant oxaliplatin, respectively. The knockdown of MRP1 resulted in the attenuation of the MDR phenotype through the induction of apoptosis. The shMRP1-transfected Colo205/5-FU cells were injected subcutaneously into the right scapular region of BALB/c nude mice and tumor size was measured for 15 days post-injection. This experiment demonstrated that MRP1 knockdown inhibited tumor growth. On the 9, 12 and 15th day post-injection, tumor volume in the shMRP1-transfected Colo205/5-FU cell-injected group was significantly lower compared with that in the Colo205/5-FU cell-injected group (day 9, 2.1±0.8 vs. 6.9±1.9 mm, P=0.009; day 12, 3.1±1.4 vs. 14.3±4.0 mm, P=0.008; day 15, 4.8±2.7 vs. 21.3±3.4 mm; all P<0.001). These results demonstrate that MRP1 serves a role in the MDR phenotype of CRC through inhibiting apoptosis and may serve as a potential therapeutic target for inhibition, which would increase the efficacy of other chemotherapeutic agents in the treatment of CRC.
多药耐药相关蛋白1（MRP1）在结直肠癌（CRC）多药耐药（MDR）中的作用仍不清楚。本研究旨在探讨MRP1在MDR CRC中的作用及其对该疾病患者的治疗潜力。通过在5个月的时间内稳定暴露于5-氟尿嘧啶（5-FU）建立了人MDR CRC细胞系HCT-8和Colo205。通过转染靶向MRP1的短发夹RNA（shMRP1）在MDR CRC细胞中敲低MRP1。进行蛋白质免疫印迹法以评估这种沉默的效率。分别进行MTT和凋亡检测以检测细胞活力和凋亡。与亲代细胞相比，HCT-8/5-FU和Colo205/5-FU细胞对5-FU的耐药性分别高23.1倍和15.8倍，对奥沙利铂的耐药性分别高17.2倍和20.9倍。MRP1的敲低通过诱导凋亡导致MDR表型的减弱。将转染shMRP1的Colo205/5-FU细胞皮下注射到BALB/c裸鼠的右肩胛区域，并在注射后15天测量肿瘤大小。该实验表明MRP1敲低抑制肿瘤生长。在注射后第9、12和15天，转染shMRP1的Colo205/5-FU细胞注射组的肿瘤体积明显低于Colo205/5-FU细胞注射组（第9天，2.1±0.8 vs. 6.9±1.9 mm，P = 0.009；第12天，3.1±1.4 vs. 14.3±4.0 mm，P = 0.008；第15天，4.8±2.7 vs. 21.3±3.4 mm；所有P<0.001）。这些结果表明，MRP1通过抑制凋亡在CRC的MDR表型中起作用，并且可能作为抑制的潜在治疗靶点，这将增加其他化疗药物在CRC治疗中的疗效。
