Identification of ERCC8 as a novel cisplatin-resistant gene in esophageal cancer based on genome-scale CRISPR/Cas9 screening.

ABSTRACT

Esophageal cancer (ESCA) is one of the most common malignant tumors of the digestive system worldwide. As a first-line drug for chemotherapy, cisplatin resistance is the major obstacle in the successful treatment of esophageal cancer. Previous studies largely failed to identify the key genes associated with cisplatin resistance. Hence, the aim of this study was to screen the cisplatin resistance-related genes of esophageal cancer using CRISPR/Cas9 gene-editing technology and Brunello iBar library. Of note, we identified ERCC8 as a novel cisplatin-resistant gene by high-throughput sequencing and cisplatin resistance assays. Based on KEGG and GO analysis, we hypothesized that the mechanism of ERCC8 involvement in cisplatin resistance is through binding to damaged DNA to perform nucleotide excision repair, contributing to the restoration of basic DNA functions and cellular life activities in ESCA. In addition, Cell proliferation and wound healing assay confirmed that ERCC8 had little effect on the proliferation and migration of esophageal cancer cells in vitro. Survival analysis showed that ERCC8 expression was not associated with OS, DSS, or FPI in patients with ESCA. Immuno-infiltration analysis indicated that increased ERCC8 expression is associated with NK cells, macrophages, T helper cells, Th1 cells, and Th2 cells. Collectively, ERCC8 may serve as a new biomarker for predicting cisplatin resistance and have the prospect of becoming an effective target for the clinical treatment of cisplatin resistance in ESCA.