The miR105/767 cluster as a coordinator of apoptosis and PD-L1 expression in non-small cell lung cancer

Abstract

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related mortality, largely due to late diagnosis, molecular diversity, and frequent development of treatment resistance. MicroRNAs (miRNAs) play critical roles in NSCLC initiation, progression, and treatment resistance. Previous studies have identified miR-105-5p and miR-767-5p , collectively referred to as the miR105/767 cluster, as being overexpressed in a subset of NSCLC that strongly associates with poor survival, including reduced benefit from immune checkpoint inhibitor (ICI) therapy. However, the functional role of this miRNA cluster in NSCLC has not been fully elucidated. Here, we investigated the biological functions of the miR105/767 cluster in lung squamous cell carcinoma (LUSC). Using in vitro modulation of miR-105-5p and miR-767-5p expression in LUSC cells, followed by RNA sequencing, bioinformatic analyses, and in silico target prediction, we characterized downstream pathways regulated by this cluster. Knockdown of miR-105-5p and miR-767-5p resulted in increased apoptosis, reduced G2–M cell-cycle progression, and impaired proliferative capacity, indicating a pro-survival role for the miR105/767 cluster. Transcriptomic and pathway enrichment analyses identified ASAH2 (N-acylsphingosine amidohydrolase 2), a key regulator of sphingolipid metabolism, as a critical downstream mediator of miR105/767 -dependent apoptotic regulation. Notably, miR-105-5p knockdown led to significant upregulation of CD274 (PD-L1) at both transcript and protein levels, while miR-105-5p overexpression suppressed PD-L1 expression, indicating direct negative regulation. Despite this interaction, miR-105-5p primarily promoted proliferation through PD-L1–independent mechanisms. In contrast, miR-767-5p overexpression induced G0 quiescence, limiting cell proliferation, while its knockdown similarly increased apoptosis and disrupted cell-cycle control. Collectively, these findings define the miR105/767 cluster as a key regulator of apoptosis, cell-cycle progression, and immune checkpoint modulation in LUSC, supporting its potential as both a prognostic biomarker and a therapeutic target in NSCLC.