Design and synthesis of lactam analogs of andrographolide and discovery of their anticancer activity as dual EGFR and VEGFR2 inhibitors.

The diterpene andrographolide, a nature-derived product, exerts a wide range of pharmacological effects, including anti-inflammatory, antiviral, immunostimulatory, and anticancer activities, due to its ability to target multiple pathways. In this study, some andrographolide derivatives of an enlarged decalin structure with a seven-membered ring or an isoxazole-fused decalin structure were designed, synthesized, and evaluated for their activity against cancer cell growth and angiogenesis. Among them, compound AGW-11 (designated as compound 8) showed potent and broad-spectrum anticancer activity and anti-angiogenic activity in vitro. Mechanistically, 8 was found to effectively suppress the phosphorylation of EGFR and ERK½ and induce 4T1 cell apoptosis in a gradient concentration-dependent manner; while 8 inhibited angiogenesis by reduction of HUVEC proliferation, tube formation and cell invasion, and decreased VEGFR2 kinase activity and lowered VEGFR2 and ERK1/2 phosphorylation. The results from in vivo anti-4T1 tumor-bearing mouse model showed that treatment with 8 significantly suppressed tumor growth and decreased the probability of lung tumor metastasis, as previously reported AGS-30 (2). Consistent with the in vitro results, the in vivo data demonstrated that the anti-angiogenic and anti-tumor effects of 8 in a mouse xenograft model. Treatment with 8 effectively inhibited expressions of Ki67, CD31 and VEGF in tumors, suggesting that 8 inhibits tumor angiogenesis. Meanwhile, the apoptotic factor cleaved caspase 3 was elevated that tumor cells was induced to death after treatment with 8. These findings will facilitate our andrographolide-related drug discovery efforts.