Calotropis gigantea (L.) Dryand. Stem bark extract suppresses tumor angiogenesis through modulation of HIF-1α/VEGF signaling and ERK1/2-AKT activation in HepG2 xenograft-bearing nude mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Calotropis gigantea (L.) Dryand. has long been used in traditional medicine to treat various disorders. However, its effects on tumor angiogenesis and the underlying molecular mechanisms in hepatocellular carcinoma remain unclear, limiting understanding of its therapeutic significance. AIM OF THE STUDY: This study aimed to investigate the anti-tumor and anti-angiogenic effects of the dichloromethane fraction of C. gigantea stem bark extract (CGD) and its associated molecular changes in a HepG2 xenograft nude mouse model. MATERIALS AND METHODS: BALB/c nude mice bearing HepG2 xenografts received intraperitoneal injections of CGD at doses of 2.5 or 5.0 mg/kg three times weekly for 4 weeks. Tumor growth was monitored. Tumor angiogenesis was assessed by immunohistochemical staining for CD31 as an index of tumor microvascular density. The expression levels of HIF-1α, VEGF, VEGFR-2, EGFR, MMP-2, MMP-9, and VE-cadherin, as well as phosphorylated ERK1/2 and AKT, were evaluated by immunohistochemistry. RESULTS: CGD treatment significantly suppressed tumor growth compared to the control group. It reduced the CD31-positive area, indicating decreased tumor vascularization. CGD significantly downregulated the expression of HIF-1α, VEGF, VEGFR-2, EGFR, MMP-2, MMP-9, and VE-cadherin. CGD decreased phosphorylated ERK1/2 and AKT levels, indicating modulation of signaling related to tumor angiogenesis and progression. CONCLUSIONS: CGD demonstrates significant anti-tumor and anti-angiogenic effects in HepG2 xenograft mice. The observed effects are associated with the modulation of HIF-1α/VEGF-related angiogenic signaling and reduced phosphorylation of ERK1/2 and AKT. Collectively, these results suggest that CGD has potential as an anti-angiogenic agent for hepatocellular carcinoma.