Research Paper Volume 14, Issue 4 pp 1836—1847

KCNQ1OT1 polymorphism rs35622507 and methylation status of KCNQ1OT1 promoter influence the drug resistance to L-OHP

Caihong Zhang1, , Yonglin Wang2, &, ,

  • 1 Proctology Department, Xing Yuan Hospital of Yulin, Yulin 719000, Shaanxi, China
  • 2 Pharmacy Department, Yangling Demonstration Zone Hospital, Xianyang 712100, Shaanxi, China

Received: July 13, 2021       Accepted: December 25, 2021       Published: February 22, 2022      

https://doi.org/10.18632/aging.203906
How to Cite

Copyright: © 2022 Zhang and Wang. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Background: LncRNA potassium voltage-gated channel subfamily Q member 1 opposite strand/antisense transcript 1 (KCNQ1OT1) has been reported to promote resistance to chemotherapy in colon cancer by inhibiting the expression of miR-34a. And the methylation of KCNQ1OT1 was also reported in the pathogenesis of various diseases. In this study, we aimed to study the combined effect of allele variation of KCNQ1OT1 polymorphism rs35622507 and methylation status of KCNQ1OT1 promoter in the treatment of colon cancer.

Methods: The expression levels of KCNQ1OT1, miR-34a, and ATG4B mRNA were assessed by qRT-PCR. ATG4B protein expression was analyzed by Western blot analysis. TUNEL and MTT assay were performed to examine the cell apoptosis and viability. Luciferase assays revealed the relationship between KCNQ1OT1, miR-34a and ATG4B.

Results: Carrier of allele 10 and methylated promoter in KCNQ1OT1 was associated with decreased KCNQ1OT1/ATG4B expression, increased miR-34a expression and enhanced apoptosis in colon cancer tissue samples. And subsequent luciferase assay showed that miR-34a could bind to KCNQ1OT1 and ATG4B at specific binding sites. The knockdown of KCNQ1OT1 significantly suppressed the KCNQ1OT1/ATG4B expression, improved the miR-34a expression and reduced the viability of HCT116 and SW480 cells. The over-expression of ATG4B notably restored the cell viability loss and apoptosis increase induced by the knockdown of KCNQ1OT1. Moreover, oxaliplatin (L-OHP) treatment elevated the apoptosis of HCT116 and SW480 cells.

Conclusions: The drug resistance in the treatment of colon cancer is most reduced in patients carrying allele 10 and methylated in KCNQ1OT1 promoter. This function is accomplished by the signaling pathway of KCNQ1OT1/miR-34a/ATG4B.

Abbreviations

lncRNA: long non-coding RNA; KCNQ1OT1: potassium voltage-gated channel subfamily Q member 1 opposite strand/antisense transcript 1; ATG4B: autophagy-related 4B cysteine peptidase; L-OHP: oxaliplatin; CRC: Colorectal cancer; 3’UTR: 3’-untranslated region; DMR1: differentially methylated region 1; KvDMR1: KvLQT1 differentially methylated region 1; MRP5: ATP binding cassette subfamily C member 5; MDR1: multi-drug resistance mutation 1; LRP1: low-density lipoprotein receptor-related protein 1; ABCC1: ATP binding cassette subfamily C member 1; THP: Tamm–Horsfall protein.