Long noncoding RNA CRART16 confers 5-FU resistance in colorectal cancer cells by sponging miR-193b-5p

Jingui Wang,Xiaoqian Zhang,Shangwen Chen,Junling Zhang,Xin Wang,Jing Zhu

doi:10.1186/s12935-021-02353-5

Abstract

BackgroundThe emergence of chemoresistance to 5-fluorouracil (5-FU)-based chemotherapy is the main cause of treatment failure in advanced and metastatic colorectal cancer (CRC) patients. Long noncoding RNAs (lncRNAs) have been reported to be involved in 5-FU resistance. Previously, we first detected that lncRNA cetuximab resistance-associated RNA transcript 16 (CRART16) could contribute to cetuximab resistance by upregulating V-Erb-B2 erythroblastic leukemia viral oncogene homologue 3 (ERBB3) expression by sponging miR-371a-5p in CRC cells. The current study aimed to explore the role of CRART16 in acquired 5-FU resistance in CRC cells and its possible mechanism.MethodsQuantitative real-time PCR (RT-qPCR) was used to measure the expression levels of CRART16 in a 5-FU-resistant CRC cell subline (SW620/5-FU) and the parent cell line. Lentivirus transduction was performed to establish SW620 and Caco-2 cells stably overexpressing CRART16. Cell Counting Kit-8 (CCK-8) assays and colony formation assays were applied to measure cell chemosensitivity to 5-FU. Flow cytometric and immunofluorescence staining were adopted to assess cell apoptosis induced by 5-FU. The dual-luciferase reporter assay was used to validate the direct interactions between CRART16 and miR-193b-5p and between miR-193b-5p and high-mobility group AT-hook-2 (HMGA2). The expression levels of HMGA2, apoptosis-associated proteins and p-ERK were examined by western blotting. The statistical differences within any two groups were used Student’s t test.ResultsCRART16 was upregulated in SW620/5-FU cells. Overexpression of CRART16 reduced the sensitivity of CRC cells to 5-FU by attenuating apoptosis. In addition, CRART16 promoted 5-FU resistance by suppressing the expression of miR-193b-5p. Furthermore, CRART16 modulated the expression of HMGA2 by inhibiting miR-193b-5p and activated the MAPK signaling pathway.ConclusionsCRART16 confers 5-FU resistance in CRC cells through the CRART16/miR-193b-5p/HMGA2/MAPK pathway.

Highlights

The emergence of chemoresistance to 5-fluorouracil (5-FU)-based chemotherapy is the main cause of treatment failure in advanced and metastatic colorectal cancer (CRC) patients
To detect whether cetuximab resistance-associated RNA transcript 16 (CRART16) is involved in the acquired resistance of CRC cells to 5-FU, its expression level in a cell line with acquired 5-FU resistance was assessed
The results demonstrated that the expression of CRART16 was significantly upregulated in SW620/5-FU cells versus parental cells (Fig. 1c), suggesting that CRART16 may participate in 5-FU-acquired resistance in CRC cells

Summary

Introduction

The emergence of chemoresistance to 5-fluorouracil (5-FU)-based chemotherapy is the main cause of treatment failure in advanced and metastatic colorectal cancer (CRC) patients. It has been documented that a considerable percentage of CRC patients and nearly half of mCRC patients experience disease progression during the course of 5-FU-based chemotherapy [6, 7]. Both primary and acquired chemoresistance are responsible for treatment failure and limit the clinical application of 5-FU [8]. Many efforts have been made to reveal the molecular mechanisms underlying chemoresistance to 5-FU in CRC, novel therapeutic targets have yet to be identified

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Conclusion