Glutathione S-Transferase Alpha 4 Promotes Proliferation and Chemoresistance in Colorectal Cancer Cells

Zhanhu Zhang; Lili Xu; Lin Huang; Tianqi Li; Jane Y Wang; Chunhua Ma; Xiaoyun Bian; Xiaoyan Ren; Haibo Li; Xingmin Wang

doi:10.3389/fonc.2022.887127

Glutathione S-Transferase Alpha 4 Promotes Proliferation and Chemoresistance in Colorectal Cancer Cells

Front Oncol. 2022 Jul 1:12:887127. doi: 10.3389/fonc.2022.887127. eCollection 2022.

Authors

Zhanhu Zhang¹, Lili Xu¹, Lin Huang², Tianqi Li¹, Jane Y Wang³, Chunhua Ma¹, Xiaoyun Bian², Xiaoyan Ren⁴, Haibo Li⁵, Xingmin Wang¹

Affiliations

¹ Institute of Genetics and Reproductive Medicine, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, China.
² Department of Gastroenterology, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, China.
³ Department of Internal Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.
⁴ Department of Pathology, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, China.
⁵ Department of Clinical Laboratory, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, China.

Abstract

Glutathione S-transferase alpha 4 (GSTA4) is a phase II detoxifying enzyme that is overexpressed in colorectal cancer (CRC) and regulated by the oncogenic transcription factor AP-1. However, the role of GSTA4 in these CRC cells remains unclear. In this study, we investigated the roles of GSTA4 in the CRC cells by inactivating GSTA4 in HCT116 human CRC cells (Defined as HCT116^ΔGSTA4) using the CRISPR/Cas9 gene editing. Cell proliferation, clonogenicity, and susceptibility to chemotherapeutic drugs were analyzed in vitro and in a xenograft model. The results showed that loss of GSTA4 significantly decreased cell proliferation and clonogenicity, whereas it increased intracellular reactive oxygen species and cell susceptibility to 5-fluorouracil (5-FU) and oxaliplatin. Additionally, exposure of HCT116^ΔGSTA4 cells to 5-FU increased the expression of γH2AX, a hallmark of double-stranded DNA breaks. In contrast, no remarkably increased γH2AX was noted in oxaliplatin-treated HCT116^ΔGSTA4 cells compared with HCT116 cells. Moreover, loss of GSTA4 blocked the AKT and p38 MAPK pathways, leading to proliferative suppression. Finally, the xenograft model showed decreased tumor size for HCT116^ΔGSTA4 cells compared with HCT116 cells, confirming in vitro findings. These findings suggest that GSTA4 is capable of promoting proliferation, tumorigenesis, and chemoresistance and is a potential target for CRC therapy.

Keywords: chemoresistance; colorectal cancer; glutathione S-transferase alpha 4; proliferation; reactive oxygen species.