Differential cytotoxicity of ethyl acetate extract of malaysian marine endophytic fungus (MKS3) against human breast cancer cell lines

Bioactive compounds produced by endophytes are progressively becoming significant in the process of drug discovery. Endophytes are microorganisms that inhabit plants and are known to produce valuable metabolites that could be potential drug leads against cancer. This study was undertaken to assess the cytotoxic profiles of ethyl acetate extract of marine endophytic fungus MKS3 originated from Terminalia sp. (locally known as "Ketapang" tree) against breast cancer cells. The fungal cultures were first examined using gross observation and environmental scanning electron microscope (ESEM). The cultures were extracted using ethyl acetate and concentrated using rotary evaporator. MCF7 and MDA468 were treated with the MKS3 (0.01-100 µg/mL) for 72 h. SRB assay was performed and data generated was used to plot the dose-response curve from which IC50 ( concentration required to inhibit 50% cell population) was determined. In general, MKS3 was more selective towards MCF7 when compared to MDA468. MKS3, however, exhibited weak cytotoxicity, with mean IC50 of 39.5 ± 21.7 µg/mL and 36.0 ± 5.7 µg/mL against MDA468 and MCF7, respectively. When compared to paclitaxel (positive control) MKS3 was at least 1,200 times less potent against breast cancer cells. When compared to tamoxifen (positive control), MKS3 was at least 5 times less potent against MCF7. Future study could be performed against other cancer cell types.