SP1 undergoes phase separation and activates RGS20 expression through super-enhancers to promote lung adenocarcinoma progression (CUT＆RUN)

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death worldwide, but the underlying molecular mechanisms remain largely unclear. The transcription factor SP1 plays a crucial role in the development of various cancers, including LUAD. Recent studies have indicated that master transcription factors may form phase-separated macromolecular condensates to promote super-enhancer assembly and oncogene expression. In this study, we demonstrated that SP1 undergoes phase separation and that its zinc finger 3 in the DNA binding domain is essential for this process. Through CUT&RUN using antibodies against SP1 and H3K27ac, we discovered a significant correlation between SP1 enrichment and super-enhancer elements, identified the regulator of G protein signaling 20 (RGS20) gene as the most likely target regulated by SP1 through super-enhancer mechanisms, and verified this finding using different approaches. The oncogenic activity of SP1 relies on its phase separation ability and RGS20 gene activation, which can be abolished by GSK-J4, a demethylase inhibitor. Together, our findings provide the first evidence that SP1 regulates its target oncogene expression through phase separation and super-enhancer mechanisms, thereby promoting LUAD cell progression. This study also revealed a novel target for LUAD therapies through intervening in SP1-mediated super-enhancer formation. We investigate the H3K27ac histone modification or SP1 profiles of H1299 cell lines.