Background
Lung cancer has become the most common cancer type and caused the most cancer deaths. Lung adenocarcinoma (LUAD) is one of the major type of lung cancer. This study aimed to establish a signature based on immune related genes that can predict patients’ OS for LUAD.
Methods
The expression data of 976 LUAD patients from The Cancer Genome Atlas database (training set) and the Gene Expression Omnibus database (four testing sets) and 1534 immune related genes from the ImmPort database were used for generation and validation of the signature. The glmnet Cox proportional hazards model was used to find the best gene model and construct the signature. To assess the independently prognostic ability of the signature, the Kaplan–Meier survival analysis and Cox’s proportional hazards model were performed.
Results
A gene model consisting of 30 immune related genes with the highest frequency after 1000 iterations was used as our signature. The signature demonstrated robust prognostic ability in both training set and testing set and could serve as an independent predictor for LUAD patients in all datasets except GSE31210. Besides, the signature could predict the overall survival (OS) of LUAD patients in different subgroups. And this signature was strongly associated with important clinicopathological factors like recurrence and TNM stage. More importantly, patients with high risk score presented high tumor mutation burden.
Conclusions
This signature could predict prognosis and reflect the tumor immune microenvironment of LUAD patients, which can promote individualized treatment and provide potential novel targets for immunotherapy.
Electronic supplementary material
The online version of this article (10.1186/s12967-019-1824-4) contains supplementary material, which is available to authorized users.
Considering the existence of immune-desert in tumor microenvironment, the clinical efficacy of immunotherapy for lung adenocarcinoma is limited. This study aims to investigate the ability of transcription factors in regulating tumor immune microenvironment in lung adenocarcinoma. RNA-seq data were collected from the The Cancer Genome Atlas database. The relationships between transcription factors and immune infiltrates were assessed. Runtrelated transcription factor 3 (RUNX3)-associated immune pathways were investigated by the Kyoto Encyclopedia of Genes and Genomes, Gene Ontology, and Gene set enrichment analysis. Upregulated chemokines in the RUNX3overexpressed cell line were determined by quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay. These chemokines were further confirmed in RUNX3-downregulated cell lines.Immunochemistry was conducted to determine the expression of RUNX3, CCL3, CCL20, and the numbers of CD8 + T lymphocytes in human lung cancer tissues. Chemokine receptors in CD8 + T cells were explored by flow cytometry and immunofluorescence. T cell recruitment was investigated by transwell assay. After screening 406 transcription factors, RUNX3 was found strongly correlated T cells, cytotoxic lymphocytes, and CD8 + T cells. RUNX3 was associated with a variety of immunomodulators, including LAG3, CTLA-4, PD-1, and TIGIT. More importantly, RUNX3 was involved in immune-related pathways, especially immune cell migration-related pathways. Further investigation exhibited RUNX3 could upregulate CCL3 and CCL20 whose receptors
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