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

Abstract

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.

Infiltrating T-cell abundance combined with EMT-related gene expression as a prognostic factor of colon cancer

“…The expression of TPM1 in colon cancer cells was lower than that in normal cells. Studies have shown that TPM1 can increase the sensitivity of colon cancer cells to chemotherapy drugs and can exert an inhibitory effect on colon cancer cells [60], which is consistent with our findings. TPM1 inhibits tumor malignant progression by regulating immune cell proliferation and development.…”

CDH1 overexpression predicts bladder cancer from early stage and inversely correlates with immune infiltration

“…ACTB2 is closely associated with cell motility, structure, and integrity; abnormal expression of this gene accelerates the invasion and metastasis of lung adenocarcinoma [40], suggesting that ACTB2 is a potential mass spectrometry-based diagnostic protein marker for BC [41]. Down-regulation of TPM1 has been detected in both gastric [42] and colorectal cancer [43] during tumor invasion and lymph node metastasis, which are closely associated with BC progression [44], suggesting a role as tumor suppressor. However, increased expression of COL3A1 in BC predicts a poor prognosis [45], consistent with our findings.…”

Study of KRAS-Related miRNA Expression in Colorectal Cancer

“…Of the miRNAs that have a targeting relationship with KRAS, miR-4770, miR-143, miR-193b, miR-429 and miR-96 showed consistent expression patterns in this study and our previous studies. 22 , 40 MiR-27b, 41 and miR-193a-3p 16 were significantly downregulated in CRC tissues, miR-96, 42 and miR-429 were significantly increased in CRC tissue compared with adjacent nontumor tissue. 43 The previously published results regarding the expression of these miRNAs are also consistent with our research results, but there are some studies with conflicting results; for example, miR-193b expression was found to be significantly upregulated in CRC, 44 miR-429 expression was found to be downregulated, HMGB3 expression was found to be upregulated in CRC tissues compared with adjacent noncancer tissues, and the expression levels of miR-429 were found to be negatively associated with those of HMGB3.…”