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Numerous proteins, peptides, and chemical agents in the venom of venomous marine animals are potentially useful biologically active molecules with pharmacological properties. The main goal of this research was to study the cytotoxic effects isolated crude venom from the Persian Gulf sea anemone, Stichodactyla haddoni against Breast, and Human embryonic kidney cell lines in vitro through using MTT assay. Samples of S. haddoni were collected from coastal waters of Lark island Persian Gulf the south of Iran. The extraction of Aqueous from tentacle was performed. The cell line was cultured in complete tissue culture medium. These cells were exposing in presence of different Serial dilution 100 to 0.78 μg of venom extract in duration time 24 hour. Analysis of statistical for cytotoxic activity of crude venom on cell lines this study showed that activity was similar together in almost all doses(Pvalue <0. 05). IC50 of crude venom against breast, and normal cell lines was observed at 4.13, 117.8µg respectively. With increasing extract concentration, death of cells on cells increased.The extraction induced more lethality on breast cell line than normal cell lines. Therefore, crude venom S.haddoni can be considered as a strong preventive grow agent against cancer cell lines especially breast cancer and with low or without toxicity on human normal cells

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Sponges are the most primitive multicellular eukaryotic organisms and sessile without defense organs therefore, they produce different secondary metabolites to protect themselves from predators and pathogens in their environment. This study aims to evaluation of cytotoxic properties of hexane and dichloromethane parts of methanol extract of the sponge (Ircinia mutans), collected from Larak Island. Hexane and dichloromethane parts were extracted by liquid-liquid extraction from methanol extract then tested by MTT colorimetric assay on three cancer cell lines MOLT-4, MCF-7 and HT-29. The hexane part with IC₅₀ value 11.53 ± 1.3, 41.64 ± 3.5 and 14.57 ± 1.5 μg/mL, and the dichloromethane part with IC₅₀ value 12.51 ± 0.8, 26.6 ± 2.2 and 7.47 ± 0.97 μg/mL respectively, on three mentioned cell line showed moderate to strong cytotoxic activity on all three cancer cell lines. The results also indicate that the dichloromethane part has stronger cytotoxic activity than the hexane part. This study's findings showed the potential of Persian Gulf sponges as valuable sources of new anti-cancer compounds.