Publication date: Jul 28, 2024

Patients with lung cancer exhibit the poorest outcomes when infected with coronavirus disease 2019 (COVID-19). However, the potential impact of COVID-19 on the tumor microenvironment (TME) of lung adenocarcinoma (LUAD) remains unknown. Expression data and clinical information were sourced from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Prognostic, differentially expressed circadian-related genes (CRGs) were identified using multivariate Cox regression and LASSO regression analyses to establish an immune-related gene signature. The clinical value, immune landscape, somatic mutations, and drug sensitivity of high- and low-risk groups were assessed using Kaplan-Meier curves and immunotherapy cohorts. Finally, in vitro and in vivo experiments were conducted to elucidate the molecular function of melatonin in regulating the immune microenvironment and therapeutic resistance. Three circadian-related patterns and distinct CRGs clusters were identified based on the abnormal expression of 13 CRGs. Circadian genomic phenotypes were identified based on 13 circadian phenotype-related differentially expressed genes (DEGs). A CRGs risk signature was constructed; the high CRGs risk group displayed an immunosuppressive TME, poor survival, and therapy resistance. Melatonin reversed EGFR-tyrosine kinase inhibitor (EGFR-TKI) resistance by regulating immune cell infiltration into the TME, both in vitro and in vivo. The investigation revealed crosstalk between CRGs signatures and immune infiltration patterns in LUAD and COVID-19. Melatonin acted as a promising agent to suppress the malignant features of lung cancer and enhance treatment sensitivity by modulating the TME.

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Original Article