Is there a correlation between the anticancer activity and unpalatability of sponges in the Florida Keys?

Sponges and their associated microorganisms are rich sources of biologically active metabolites with potential for new therapeutic treatments. Many of these compounds are produced in the response to environmental pressures including the threat of predation and infection. In our investigation for new chemotherapeutics for ovarian cancer, we are exploring the potential of using ecological evidence of un-palatability of sponge extracts as a mechanism to identify chemically rich extracts of sponges in the Florida Keys. Partitioned extracts were tested in palatability assays against a generalist fish, Lagodon rhomboides, a common hermit crab and sea urchin. Partitions were also tested against human ovarian cancer cells (HeyA8, ES2, and EG) using an MTT cell proliferation assay (5 mg/mL) at 24, 48, and 72 hours after treatment. Activity against HayA8 was observed in the water and chloroform partitions of FL-17 and against ES2 in the chloroform and methanol partitions. In addition, the outer layer of FL-1308 is active against the ES2 cells while the inner layer was not suggesting that the active compounds are concentrated in the outer layer of the sponge. Invasion assays assessing metastatic ability and PI/annexin V-FITC staining will be performed assessing apoptotic induction with the active extracts. Feeding studies of the extracts show reduced consumption by generalist predators. Ongoing in vitro studies will address other physiologically relevant targets of cancer cell biology. Once completed we, will look for correlations between biological and ecological activities.