Genome-wide CRISPR-Cas9 screening identifies that hypoxia-inducible factor-1a-induced CBX8 transcription promotes pancreatic cancer progression via IRS1/AKT axis

Bu-Wei Teng; Kun-Dong Zhang; Yu-Han Yang; Zeng-Ya Guo; Wei-Wei Chen; Zheng-Jun Qiu

doi:10.4251/wjgo.v13.i11.1709

Genome-wide CRISPR-Cas9 screening identifies that hypoxia-inducible factor-1a-induced CBX8 transcription promotes pancreatic cancer progression via IRS1/AKT axis

World J Gastrointest Oncol. 2021 Nov 15;13(11):1709-1724. doi: 10.4251/wjgo.v13.i11.1709.

Authors

Bu-Wei Teng¹, Kun-Dong Zhang², Yu-Han Yang², Zeng-Ya Guo², Wei-Wei Chen², Zheng-Jun Qiu³

Affiliations

¹ Shanghai General Hospital of Nanjing Medical University, 100 Haining Road, Shanghai 200080, China.
² Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University, Shanghai 200080, China.
³ Shanghai General Hospital of Nanjing Medical University, 100 Haining Road, Shanghai 200080, China. qiuzjdoctor@sina.com.

Abstract

Background: Pancreatic cancer (PC) is one of the most lethal malignancies worldwide. It is known that the proliferation of PC cells is a critical process in the disease. Previous studies have failed to identify the key genes associated with PC cell proliferation, using bioinformatic analysis, genome-wide association studies, and candidate gene testing.

Aim: To investigate the function of the chromobox 8 (CBX8)/receptor substrate 1 (IRS1)/AKT axis in PC.

Methods: A genome-wide CRISPR-Cas9 screening was performed to select genes that could facilitate PC cell proliferation. Quantitative reverse transcription-polymerase chain reaction was used to detect the expression of CBX8 in PC tissues and cells. The regulatory roles of CBX8 in cell proliferation, migration, and invasion were verified by in vivo and in vitro functional assays.

Results: CBX8 was upregulated in PC tissues and shown to drive PC cell proliferation. Higher expression of CBX8 was correlated with worse outcomes of PC patients from two independent cohorts comprising a total of 116 cases. CBX8 was also proved to serve as a promising therapeutic target for a PC xenograft model. We demonstrated that hypoxia-inducible factor (HIF)-1a induced CBX8 transcription by binding to the promoter of CBX8. CBX8 efficiently activated the PI3K/AKT signaling by upregulating insulin IRS1.

Conclusion: CBX8 is a key gene regulated by HIF-1α, and activates the IRS1/AKT pathway, which suggests that targeting CBX8 may be a promising therapeutic strategy for PC.

Keywords: CRISPR-Cas9 screening; Chromobox 8; Hypoxia; Pancreatic cancer; pI3K/AKT signaling.