OncoTargets and Therapy (May 2021)

Comparative Analysis and in vitro Experiments of Signatures and Prognostic Value of Immune Checkpoint Genes in Colorectal Cancer

  • Ma R,
  • Qu X,
  • Che X,
  • Yang B,
  • Li C,
  • Hou K,
  • Guo T,
  • Xiao J,
  • Liu Y

Journal volume & issue
Vol. Volume 14
pp. 3517 – 3534

Abstract

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Rui Ma,1– 4 Xiujuan Qu,1– 4 Xiaofang Che,1– 4 Bowen Yang,1– 4 Ce Li,1– 4 Kezuo Hou,1– 4 Tianshu Guo,1– 4 Jiawen Xiao,5 Yunpeng Liu1– 4 1Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, 110001, People’s Republic of China; 2Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, China Liaoning Province Clinical Research Center for Cancer, Shenyang, 110001, People’s Republic of China; 3Liaoning Province Clinical Research Center for Cancer, Shenyang, 110001, People’s Republic of China; 4Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, Shenyang, 110001, People’s Republic of China; 5Department of Medical Oncology, Shenyang Fifth People Hospital, Shenyang, People’s Republic of ChinaCorrespondence: Yunpeng Liu; Xiujuan QuDepartment of Medical Oncology, The First Hospital of China Medical University, No. 155, North Nanjing Street, Heping District, Shenyang, 110001, People’s Republic of ChinaTel +86-24-83282312Fax +86-24-83282543Email [email protected]; [email protected]: Immune checkpoints, as pivotal regulators of immune escape in cancer, can motivate the emergence of immune checkpoint inhibitors (ICIs). The aim of this study is to identify the expression of the immune checkpoint genes (ICGs) in colorectal cancer (CRC) and to relate their individual as well as combined expression to prognosis and therapeutic effectiveness in CRC.Methods: RNA expression of 47 ICGs and clinical information of CRC patients were collected from two public databases to elucidate the expression levels and prognostic values of these ICGs in CRC. Then, the Shapiro–Wilk normality test was used to determine the normality of variables. Overall survival (OS) rates of each subset were found by Kaplan–Meier method, and the statistical significance was determined by the Log rank test (p < 0.05).Results: The expression of 13 and 9 ICGs was significantly associated with CRC prognosis in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cohorts. A series of ICGs was found to be significantly associated with TMB, neoantigens and MMR in CRC indicating that the combination of immunotherapy treatment biomarkers and ICGs may achieve accurate prognostic stratification of CRC, and potentially identify CRC cases that might respond to checkpoint inhibitors (CPIs). The subsets of high or low PD1/PD-L1/IDO1 expression stratified by CD48 were accurately associated with prognosis in CRC. In addition, in vitro experiments confirmed that VTCN1(B7-H4)-KD increases anti-PD-L1-mediated NK cell cytotoxicity on CRC tumor cells.Conclusion: Although the expression of a single immune-checkpoint molecule does not predict the efficacy of immunotherapy in CRC, our findings infer that subsets defined by ICGs are associated with prognosis and imply the possibility that VTCN1 and CD48 serve as new immunotherapeutic targets.Keywords: immune checkpoint genes, colorectal cancer, prognosis, immunotherapy

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