Anti-proliferative potential of secondary metabolites from the marine sponge theonella sp. Moving from correlation toward causation

Marine sponges have been recognized as a rich source of potential anti-proliferative metabolites. Currently, there are two sponge-derived anti-cancer agents (a macrolide and a nucleoside) isolated from the Porifera phylum, suggesting the great potential of this sponge as a rich source for anti-neoplastic agents. To search for more bioactive metabolites from this phylum, we examined the EtOAc extract of Theonella sp. sponge. We isolated seven compounds (1–7), including four 4-meth-ylene sterols (1–4), two nucleosides (5 and 6), and one macrolide (7). Among them, theonellasterol L (1) was identified for the first time, while 5′-O-acetyl-2′-deoxyuridine (5) and 5′-O-acetylthymidine (6) were the first identified deoxyuridine and thymidine derivatives from the sponge Theonella sp. These structures were elucidated based on their spectroscopic data. The anti-proliferation activity of compounds 1–7 against the MCF-7, MDA-MB-231, T-47D, HCT-116, DLD-1, K562, and Molt 4 cancer cell lines was determined. The results indicated that the 14-/15-oxygenated moiety played an important role in the antiproliferative activity and the macrolide derivatives dominated the anti-proliferative effect of the sponge Theonella sp. The in silico analysis, using a chemical global positioning system for natural products (ChemGPS-NP), indicated an anti-proliferative mode of actions (MOA) suggesting the potential applications of the isolated active metabolites as anti-proliferative agents.