1,8-Dihydroxy-3-methoxy-anthraquinone inhibits tumor angiogenesis through HIF-1α downregulation

Photorhabdus luminescens is a gram-negative bioluminescent bacterium known as an intestinal bacterium that coexists in the digestive tract of insect-pathogenic nematodes. As part of our ongoing exploration to identify bioactive compounds from diverse natural resources, the chemical analysis of the cultures of P. luminescens KACC 12254 via LC/MS and TLC-based analyses enabled the isolation and identification of a major fluorescent compound. Its chemical structure was elucidated as 1,8-dihydroxy-3-methoxyanthraquinone (DMA) using HR-ESI-MS and NMR analysis. In this study, we conducted comprehensive investigations utilizing human colorectal cancer HCT116 cells, human umbilical cord vascular endothelial cells (HUVECs), and zebrafish embryos to assess the potential benefits of DMA in suppressing tumor angiogenesis. Our results convincingly demonstrate that DMA effectively suppresses the stability of hypoxia-inducible factor-1α (HIF-1α) protein and its target genes without inducing any cytotoxic effects. Furthermore, DMA demonstrates the ability to inhibit HIF-1α transcriptional activation and mitigate the production of reactive oxygen species (ROS). In our in vitro experiments, DMA exhibits notable inhibitory effects on VEGF-mediated tube formation, migration, and invasion in HUVECs. Additionally, in vivo investigations using zebrafish embryos confirm the antiangiogenic properties of DMA. Notably, DMA does not exhibit any adverse developmental or cardiotoxic effects in the in vivo setting. Moreover, we observe DMA's capability to restrain tumor growth through the downregulation of PI3K/AKT and c-RAF/ERK pathway. Collectively, these compelling findings underscore DMA's potential as a promising therapeutic candidate for targeted intervention against HIF-1α and angiogenesis in cancer treatment.