(+)-Aeroplysinin-1 is a metabolite originally isolated from the marine sponge V. aerophoba with diverse biological activities. (+)-Aeroplysinin-1 (0.25-0.5 μM) induces cell death in MCF-7 and ZR-75-1 human breast cancer cells in a time- and concentration-dependent manner but has no effect on normal human fibroblasts at concentrations up to 5 μM. It also blocks EGF-induced endocytosis of the EGF receptor (EGFR) and EGF-dependent cell proliferation in MCF-7 cells. (+)-Aeroplysinin-1 inhibits bovine aortic endothelial (BAE) cell proliferation and cord formation in a Matrigel™ assay. It inhibits angiogenesis in a dose-dependent manner in a chick chorioallantoic membrane (CAM) assay when administered from 1.5 to 3 nmol per egg. (+)-Aeroplysinin-1 also has antibacterial activity against Gram-positive bacteria, including S. aureus, S. albus, and B. subtilis, but not Gram-negative bacteria and inhibits HIV-1 replication (IC = 14.6 μM) via inhibition of HIV-1 reverse transcriptase.