Xiao Zhenhuan, Liu Yun, Li Qun, Liu Qinyuan, Liu Yong, Luo Yan, Wei Songzhi
Department of General Surgery, The Shenzhen Hospital of Southern Medical University, Shenzhen, China.
Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China.
Cancer Chemother Pharmacol. 2021 Dec;88(6):1021-1031. doi: 10.1007/s00280-021-04348-5. Epub 2021 Oct 2.
Oxaliplatin is a crucial component of the combinatorial chemotherapeutic standard of care for advanced colorectal cancer (CRC). Unfortunately, a serious barrier to effective oxaliplatin treatment is drug resistance due to epithelial-mesenchymal transitioning (EMT). Interestingly, stable oxaliplatin-resistant CRC cell lines show differential expression of miR-1915-3p; thus, this microRNA may represent a potential modifier of oxaliplatin resistance in CRC cells.
miR-1915-3p was over-expressed in oxaliplatin-resistant CRC cells and a non-tumorigenic intestinal cell line (FHC) via lentiviral transduction. Extracellular vesicles (EVs) were purified from transduced FHC cells and co-incubated with CRC cells. Expression levels of miR-1915-3p and other RNA species were assessed by RT-qPCR, while protein expression levels were assessed by Western blotting. The effects of miR-1915-3p on CRC viability were evaluated by proliferation, apoptosis assays, and Transwell assays. Effects of miR-1915-3p over-expression on in vivo oxaliplatin sensitivity was tested via murine xenograft models.
miRNA-1915-3p decreased EMT marker expression in oxaliplatin-resistant CRC cell lines and in vivo. FHC cells were able to produce and secrete miR-1915-3p-containing EVs, which we employed to mediate miR-1915-3p delivery to oxaliplatin-resistant CRC cells and increase their oxaliplatin sensitivity in vivo and in vitro. Mechanistically, miR-1915-3p overexpression downregulated the EMT-promoting oncogenes 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and ubiquitin carboxyl-terminal hydrolase 2 (USP2) as well as upregulated E-cadherin (a cell adhesion mediator). miR-1915-3p's effects on chemosensitivity and EMT were mediated by its regulation of PFKFB3 and USP2.
Exosomal delivery of miR-1915-3p can improve the chemotherapeutic efficacy of oxaliplatin in CRC cells by suppressing the EMT-promoting oncogenes PFKFB3 and USP2.
奥沙利铂是晚期结直肠癌（CRC）联合化疗标准治疗方案的关键组成部分。不幸的是，上皮-间质转化（EMT）导致的耐药性是奥沙利铂有效治疗的一个严重障碍。有趣的是，稳定的奥沙利铂耐药CRC细胞系显示出miR-1915-3p的差异表达；因此，这种微小RNA可能是CRC细胞中奥沙利铂耐药性的潜在调节因子。
通过慢病毒转导在奥沙利铂耐药的CRC细胞和非致瘤性肠细胞系（FHC）中过表达miR-1915-3p。从转导的FHC细胞中纯化细胞外囊泡（EVs），并与CRC细胞共同孵育。通过RT-qPCR评估miR-1915-3p和其他RNA种类的表达水平，通过蛋白质印迹评估蛋白质表达水平。通过增殖、凋亡检测和Transwell检测评估miR-1915-3p对CRC活力的影响。通过小鼠异种移植模型测试miR-1915-3p过表达对体内奥沙利铂敏感性的影响。
miRNA-1915-3p在奥沙利铂耐药的CRC细胞系和体内降低了EMT标志物的表达。FHC细胞能够产生并分泌含有miR-1915-3p的EVs，我们利用这些EVs将miR-1915-3p递送至奥沙利铂耐药的CRC细胞，并在体内和体外提高它们对奥沙利铂的敏感性。从机制上讲，miR-1915-3p过表达下调了促进EMT的癌基因6-磷酸果糖-2-激酶/果糖-2,6-二磷酸酶3（PFKFB3）和泛素羧基末端水解酶2（USP2），并上调了E-钙黏蛋白（一种细胞黏附介质）。miR-1915-3p对化疗敏感性和EMT的影响是通过其对PFKFB3和USP2的调节介导的。
外泌体递送miR-1915-3p可通过抑制促进EMT的癌基因PFKFB3和USP2提高奥沙利铂对CRC细胞的化疗疗效。
