Identification of Key Genes and Pathways associated with Chemotherapy and Radiotherapy Sensitivity in Locally Advanced Cervical Cancer
Authors: Zhang Zhenhua , Zhang Yao , Ma Yongshun , Xiang Shixing , Shen Jing , Zhao Yueshui , Wu Xu , Li Mingxing , Yang Xiao , Kaboli Parham Jabbarzadeh , Du Fukuan , Ji Huijiao , Liu Lin , Xiao Zhangang , Li Jing , Wen Qinglian 
Published: December 2020

Abstract
Objectives：Currently, the standard treatment approach for locally advanced cervical cancer (LACC) is concurrent chemoradiotherapy (CCRT). However, resistance to radiotherapy and chemotherapy often leads to treatment failure. Intrinsic resistance is often a decisive factor in treatment response. Thus, it is urgent to identify the key genes and pathways associated with CCRT sensitivity in LACC.Materials and Methods：We searched the Gene Expression Omnibus (GEO) database for patients with LACC and analyzed differentially expressed genes (DEGs) between responders and non-responders. Gene Ontology (GO) enrichment analysis of DEGs were performed using DAVID tools. And Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs were conducted using R package cluster Profiler. The Weighted Gene Co-Expression Network Analysis (WGCNA) from R package WGCNA was used for the identification of highly correlated gene modules. A protein-protein interaction (PPI) network was constructed using STRING and 20 hub genes were selected. The expression levels of these 20 genes were was analyzed using The Cancer Genome Atlas (TCGA) and Gene Expression Profiling Interactive Analysis (GEPIA 2) databases. Furthermore, single-cell transcriptome sequencing was used to elucidate the cell type composition of the cervix sample and analyze the expression levels of 10 hub genes in cells.Results: Compared with non-responders, 580 genes were significantly up-regulated. The up-regulated genes were mainly related to Human papillomavirus infection, focal adhesion, and ECM-receptor interaction signaling pathway. We screened 10 hub genes (COL1A1, COL6A1, COL6A2, LAMA4, COL6A3, LAMC1, HSPG2, ITGA9, CTGF, PDGFRB) and further studied them. Compared with healthy people, these 10 genes were low expressed in cervical cancer patients, and their mRNA levels were positively correlated. Receiver Operator Characteristic curve (ROC) analysis indicated that 10 hub genes could differentiate responders from non-responders. Furthermore, we showed that COL1A1, COL6A1, COL6A2 were highly expressed after radiotherapy or chemoradiotherapy. By analyzing the single-cell sequence, we found that the main cell types in cervical tissue include Fibroblasts, Smooth muscle cells, Tissue stem cells, Endothelial cells, Progenitor cells, Epithelial cells, T cells, Basal cells, Macrophages, and Mast cells. And COL1A1, COL6A1, COL6A2, COL6A3, CTGF, PDGFRB were highly expressed in Progenitor cells.Conclusions: In summary, COL1A1, COL6A1, COL6A2, LAMA4, COL6A3, LAMC1, HSPG2, ITGA9, CTGF, and PDGFRB might serve as therapeutic targets to enhance the therapeutic effect of CCRT in the treatment of LACC. These genes were involved in Human papillomavirus infection, focal adhesion, and ECM-receptor interaction signaling pathway. And they were involved in various biological processes, including cell adhesion and extracellular matrix organizations. Besides, COL1A1, COL6A1, COL6A2, COL6A3, CTGF, and PDGFRB were highly expressed in Progenitor cells.