LncRNA TUG1 Facilitates Colorectal Cancer Stem Cell Characteristics and Chemoresistance by Enhancing GATA6 Protein Stability.

Haowei Jia,Hangyuan Zhou,Guanghui Liu,Xingqi Bao,Hongchao Zhao,Junfeng Sun,Yue Wu

doi:10.1155/2021/1075481

Haowei Jia, Hangyuan Zhou

Open Access

https://doi.org/10.1155/2021/1075481

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Abstract

Background Chemoresistance and tumor recurrence lead to high deaths in colorectal cancer (CRC) patients. Cancer stem cells (CSCs) contribute to these pathologic properties, but the exact mechanisms are still poorly understood. This study identified that long noncoding RNA (lncRNA) TUG1 was highly expressed in CRC stem cells and investigated its mechanism. Methods After the CD133+/CD44+ cells with cancer stem cell (CSC) characteristics were isolated and identified by flow cytometry, lncRNA TUG1 expression was quantified by quantitative real-time PCR. The lncRNA TUG1 function was further investigated using gain- and loss-of-function assays, sphere formation, Western blot, Cell Counting Kit-8 assay, and cell apoptosis detection. Moreover, the mechanism was explored by RNA pull-down assay, RNA immunoprecipitation, and cycloheximide- (CHX-) chase assays. Results lncRNA TUG1 was elevated in CD133+/CD44+ cells with CSC characteristics. Functionally, lncRNA TUG1 increased the characteristics and oxaliplatin resistance of CRC stem cells. Mechanically, lncRNA TUG1 interacted with GATA6 and positively regulated its protein level and the rescue assays corroborated that lncRNA TUG1 knockdown repressed the characteristics and oxaliplatin resistance of CRC stem cells by decreasing GATA6 and functioned in CRC by targeting the GATA6-BMP signaling pathway. Furthermore, the in vivo assay verified the lncRNA TUG1 function in facilitating the characteristics and oxaliplatin resistance of CRC stem cells. Conclusion lncRNA TUG1 facilitated CRC stem cell characteristics and chemoresistance by enhancing GATA6 protein stability.

Highlights

Colorectal cancer (CRC) is one of the most common malignancies worldwide and is a momentous cause of cancerrelated death [1]
We demonstrated that long noncoding RNA (lncRNA) Taurine upregulated gene 1 (TUG1) was elevated in colorectal cancer (CRC) stem cells and lncRNA TUG1 accelerated the characteristics and chemoresistance of CRC stem cells, and we further investigated the mechanism through various molecular techniques
To assess the lncRNA TUG1 impact on the GATA binding protein 6 (GATA6) protein degradation, si-TUG1 was transfected into CD133-/CD44- or CD133+/CD44+ isolated from SW480 cells, and the cells were treated with 100 μg/ml cycloheximide (CHX, #HY-12320, MedChemExpress) for 0, 4, and 8 h

Summary

Background

Chemoresistance and tumor recurrence lead to high deaths in colorectal cancer (CRC) patients. Cancer stem cells (CSCs) contribute to these pathologic properties, but the exact mechanisms are still poorly understood. This study identified that long noncoding RNA (lncRNA) TUG1 was highly expressed in CRC stem cells and investigated its mechanism. After the CD133+/CD44+ cells with cancer stem cell (CSC) characteristics were isolated and identified by flow cytometry, lncRNA TUG1 expression was quantified by quantitative real-time PCR. LncRNA TUG1 increased the characteristics and oxaliplatin resistance of CRC stem cells. LncRNA TUG1 interacted with GATA6 and positively regulated its protein level and the rescue assays corroborated that lncRNA TUG1 knockdown repressed the characteristics and oxaliplatin resistance of CRC stem cells by decreasing GATA6 and functioned in CRC by targeting the GATA6-BMP signaling pathway. The in vivo assay verified the lncRNA TUG1 function in facilitating the characteristics and oxaliplatin resistance of CRC stem cells. Conclusion. lncRNA TUG1 facilitated CRC stem cell characteristics and chemoresistance by enhancing GATA6 protein stability

Introduction

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