KRAS/PI3K axis driven GTF3C6 expression and promotes LUAD via FAK pathway

Abstract

Effective targeting drugs for KRAS mutation-mediated Lung Adenocarcinoma (LUAD) are currently are limited. Investigating and intervening in the downstream key target genes of KRAS is crucial for clinically managing KRAS mutant-driven LUAD. GTF3C6, a newly identified member of the general transcription factor III (GTF3) family, plays a role in the transcription of RNA polymerase III (pol III)-dependent genes. However, its involvement in cancer remains unexplored. This study examined the expression, roles, and potential molecular mechanisms of GTF3C6 in LUAD tissues, LSL-Kras;LSL-p53 LUAD mouse models, and LUAD patients-derived organoid using Western blot, qRT-PCR, immunofluorescence, immunohistochemistry, and gene manipulation assays. We present the first evidence that GTF3C6 is highly expressed in LUAD tissues, LSL-Kras;LSL-p53 LUAD mouse models, and LUAD organoids, correlating with poor clinical prognosis. Furthermore, GTF3C6 was found to promote anchorage-independent proliferation, migration, and invasion of LUAD cells. Mechanistically, KRAS mutation drives GTF3C6 expression through the PI3K pathway, and GTF3C6 knockdown reverses the malignant phenotype of KRAS mutation-driven LUAD cells. Additionally, the FAK pathway emerged as a crucial downstream signaling pathway through which GTF3C6 mediates the malignant phenotype of LUAD. Finally, GTF3C6 knockdown suppresses LUAD organoid formation and inhibits tumor growth in vivo. Our findings demonstrate that GTF3C6, driven by KRAS mutation, promotes LUAD development by regulating FAK phosphorylation, suggesting its potential as a biomarker and therapeutic target in KRAS mutant-driven LUAD.