Abstract 1488: The role of epithelial miR-149 in immune modulation and progression of bronchial premalignant lesions

Abstract The molecular events involved in the development of bronchial premalignant lesions (PMLs), and their progression to lung squamous cell carcinoma, are not well understood. Prior work characterized lung PML molecular subtypes by identifying co-expressed gene modules associated with histologic severity and progression/persistence. The proliferative subtype was enriched for PMLs with dysplasia. Genes related to interferon signaling and antigen processing/presentation (Module 9) were decreased in progressive/persistent lesions within this subtype, suggesting early immune suppression is related to PML progression. However, the mechanisms that drive these alterations are unclear. We investigated the role of microRNAs (miRNAs) in regulating gene expression associated with PML outcomes. mRNA and miRNA were extracted and sequenced from longitudinally collected endobronchial biopsies from patients with PMLs (148 samples, 30 patients). miRNAs targeting each gene co-expression module were identified based on target gene enrichment and the degree of negative correlation between the miRNA expression and its targets. Expression association with outcome within the proliferative subtype was tested with a mixed effects model adjusting for batch and patient as random effect. Cell type specificity of miRNA expression was tested based on cell type specific sequencing data from FANTOM5 and cell type marker correlation analysis. Genes regulated by NLRC5 were identified with ChIPseq data from Ludigs et al. Target gene suppression was confirmed by transfecting SW900 cells with miR-149-5p. miR-149-5p level in PML biopsies was examined by miRNA in situ hybridization (miR-ISH). miR-149-5p is identified as potential regulator of Module 9 gene expression and is significantly up-regulated in progressive/persistent PMLs. Its expression is highly enriched in epithelial cells in FANTOM5 and positively correlates with basal cell markers within PMLs. Predicted targets of miR-149-5p are down-regulated in the progressive PMLs in both our and data from Merrick et al. MHC-I and related gene expressions are down-regulated in progressing/persistent PMLs. These genes are regulated by the transcriptional coactivator NLRC5 which is a predicted target gene of miR-149-5p. We find that overexpressing miR-149-5p in SW900 cells decreases the expression levels of both NLRC5 and NLRC5 regulated genes. Additionally, miR-ISH targeting miR-149-5p in proliferative biopsy samples confirm its expression in epithelium compartment and association with outcome. Our data suggest epithelial miR-149-5p might be a key regulator of gene expression contributing to PML progression. We hypothesize that by suppressing NLRC5, miR-149-5p inhibits MHC-I gene expression of epithelial cells, promoting early immune depletion and lesion progression. miR-149-5p might therefore be a therapeutic target for preventing PML progression. Citation Format: Boting Ning, Roxana M. Pfefferkorn, Gang Liu, Sherry Zhang, Hanqiao Liu, Christopher Stevenson, Sarah A. Mazzilli, Avrum E. Spira, Marc E. Lenburg, Jennifer E. Beane. The role of epithelial miR-149 in immune modulation and progression of bronchial premalignant lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1488.