The chromatin remodeling factor BAP18 promotes non–small cell lung cancer progression via the recruitment of β-catenin with the transcriptional coactivator complex ACTL6A–PAF1

Non-small cell lung cancer (NSCLC) is a prevalent and deadly form of lung cancer, with treatment challenges including drug resistance and limited therapeutic targets, despite advances, such as immune checkpoint inhibitors. This study investigated the role of BAP18 (BPTF-associated protein of 18 kDa), a chromatin-associated protein, in NSCLC progression and its potential as a therapeutic target. NSCLC tissue samples were analyzed for BAP18 expression using Western blot and immunohistochemistry, and NSCLC cell lines with BAP18 knockdown were assessed for proliferation, migration, cell cycle, and tumor growth through in vitro assays and xenograft models. Coimmunoprecipitation and luciferase reporter assays were used to explore the interaction of BAP18 with β-catenin, ACTL6A (actin like 6A), and PAF1 (polymerase-associated factor 1) and its impact on β-catenin-mediated transcriptional activity. RNA sequencing and enrichment analyses identified the pathways involved in BAP18-regulated NSCLC progression. The results showed that BAP18 is highly expressed in NSCLC tissues, and its knockdown significantly inhibited cell proliferation, migration, and tumor growth. Mechanistically, BAP18 recruits ACTL6A and PAF1 to Wnt (wingless/integrated) target gene promoters, enhancing β-catenin-mediated transcription. These findings suggest that BAP18 plays a critical role in NSCLC progression through the Wnt-β-catenin pathway and could serve as a novel therapeutic target, particularly for patients with Wnt-β-catenin-driven tumors.