Inhibition of miR-96 enhances the sensitivity of colorectal cancer cells to oxaliplatin by targeting TPM1

• Published in: Experimental and therapeutic medicine 2020-09, Vol.20 (3), p.2134-2140
• Main Authors: Ge, Tingrui, Xiang, Ping, Mao, Haibing, Tang, Shumin, Zhou, Jinyi, Zhang, Yonggang
• Format: Article
• Language: English
• Subjects: Apoptosis; Binding sites; Biotechnology; Cancer therapies; Care and treatment; Cell growth; Colorectal cancer; Comparative analysis; Flow cytometry; Health aspects; Luciferase; Metastasis; MicroRNA; MicroRNAs; Muscle proteins; Online data bases; Proteins; Reagents
• ISSN: 1792-0981; 1792-1015
• DOI: 10.3892/etm.2020.8936

Colorectal cancer (CRC) is one of the major threats to human health worldwide. In the treatment of CRC, chemoresistance affects the efficacy of platinum-based therapies. Oxaliplatin is one of the most commonly used first-line medications for the treatment of CRC; however, chemoresistance is common among patients receiving oxaliplatin treatment, which significantly decreases its therapeutic efficacy. The present study focused on the roles of microRNA (miR)-96 in the oxaliplatin resistance of CRC cells and the underlying mechanisms. First, the expression of miR-96 was compared between CRC and adjacent tissues. Furthermore, target genes of miR-96 were predicted, and a dual-luciferase reporter assay was employed to confirm whether the candidate tropomyosin 1 (TPM1) is a direct target of miR-96. In addition, CRC cells were transfected with miR-96 inhibitor, miR-negative control, small interfering RNA (siRNA) targeting TPM1 or siRNA NC, and then treated with oxaliplatin. CCK-8 assay and flow cytometry were performed to examine the proliferation and apoptosis of the CRC cell line SW480. Next, reverse transcription-quantitative PCR and western blot analysis were performed to determine the mRNA and/or protein levels of miR-96, Bcl-2, BAX and TPM1. The results indicated that miR-96 was upregulated in CRC compared with normal adjacent tissues, while TPM1 was downregulated. The luciferase activity was reduced following transfection with miR-96 mimics and luciferase reporter plasmid containing the wild-type sequence of the 3'-untranslated region of TPM1. Furthermore, knockdown of miR-96 combined with oxaliplatin reduced the viability and induced apoptosis of CRC cells, which was further verified by decreased expression of Bcl-2 and the increased expression of TPM1 and BAX. Taken together, the downregulation of miR-96 enhanced the sensitivity of CRC cells to oxaliplatin.