Oxygen-dependent regulation of ADAMTS1 by VEGFA defines a novel VEGFA-HIF-ADAMTS1 axis in hepatocellular cancer.

ADAMTS1 is a matrix-associated protease involved in angiogenesis and tumor microenvironment remodeling, and its regulation under oxygen-limited conditions has not been fully elucidated. Vascular endothelial growth factor A (VEGFA) is one of the key regulators of angiogenesis and hypoxic signaling. This study aimed to reveal the effects of VEGFA on ADAMTS1 gene expression, promoter activity, and related signaling pathways under normoxic and hypoxic conditions. The findings show that VEGFA regulates ADAMTS1 expression in a time- and oxygen level-dependent manner. Under hypoxic conditions, ADAMTS1 mRNA and protein levels exhibited a biphasic increase, showing a stronger and more persistent response than that under normoxic conditions. Promoter analyses showed that under normoxic conditions, VEGFA suppressed transcriptional activity in both the long (P1) and short (P7) promoter regions, whereas under hypoxic conditions, it decreased P1 activity but induced activation in the P7 region. The partial reversal of this effect by the MEK/ERK inhibitor PD98059 confirmed the role of this pathway in the transcriptional control of VEGFA. Chromatin immunoprecipitation-qPCR further demonstrated oxygen-dependent recruitment of ELK1, c-JUN, and notably ATF-1 to multiple ADAMTS1 promoter regions, with hypoxia inducing a marked and widespread increase in ATF-1 occupancy. Furthermore, it has been determined that VEGFA creates an oxygen-sensitive positive feedback loop by increasing its own expression and HIF-1α stabilization, which in turn enhances ADAMTS1 induction. Integrative bioinformatic analyses of GEO and TCGA-LIHC datasets supported these experimental findings, revealing hypoxia-associated upregulation of VEGFA, positive correlations between hypoxia scores and VEGFA/HIF1A expression, and context-dependent associations between ADAMTS1 expression, hypoxia signaling, and angiogenesis-related gene networks. These results identify ADAMTS1 as a hypoxia-responsive gene regulated through VEGFA-driven convergence of MAPK and PI3K/AKT signaling on a transcriptionally complex promoter, providing mechanistic insight into hypoxia-associated extracellular matrix remodeling in cancer.