Taxol Produced from Endophytic Fungi Induces Apoptosis in Human Breast, Cervical and Ovarian Cancer Cells


Currently, taxol is mainly extracted from the bark of yews; however, this method can not meet its increasingdemand on the market because yews grow very slowly and are a rare and endangered species belonging to firstlevelconservation plants. Recently, increasing efforts have been made to develop alternative means of taxolproduction; microbe fermentation would be a very promising method to increase the production scale of taxol.To determine the activities of the taxol extracted from endophytic fungus N. sylviforme HDFS4-26 in inhibitingthe growth and causing the apoptosis of cancer cells, on comparison with the taxol extracted from the bark ofyew, we used cellular morphology, cell counting kit (CCK-8) assay, staining (HO33258/PI and Giemsa), DNAagarose gel electrophoresis and flow cytometry (FCM) analyses to determine the apoptosis status of breastcancer MCF-7 cells, cervical cancer HeLa cells and ovarian cancer HO8910 cells. Our results showed that thefungal taxol inhibited the growth of MCF-7, HeLa and HO8910 cells in a dose-and time-dependent manner.IC50 values of fungal taxol for HeLa, MCF-7 and HO8910 cells were 0.1-1.0 μg/ml, 0.001-0.01 μg/ml and 0.01-0.1 μg/ml, respectively. The fungal taxol induced these tumor cells to undergo apoptosis with typical apoptoticcharacteristics, including morphological changes for chromatin condensation, chromatin crescent formation,nucleus fragmentation, apoptotic body formation and G2/M cell cycle arrest. The fungal taxol at the 0.01-1.0 μg/ml had significant effects of inducing apoptosis between 24-48 h, which was the same as that of taxol extractedfrom yews. This study offers important information and a new resource for the production of an importantanticancer drug by endofungus fermentation.