Cytotoxic activities of ethanolic crude extracts from fruiting bodies of bamboo mushrooms (Dictyophora spp.) against cholangiocarcinoma cells

Introduction: Cholangiocarcinoma (CCA) is a highly progressive tumor. The standard chemotherapy varies in its effectiveness, with generally low efficacy. So, the discovery of novel chemotherapy is still required. The objective of this preliminary study was to determine the cytotoxic effects induced by three kinds of bamboo mushrooms (Dictyophora indusiata or Chinese bamboo mushroom; Ch-DTP, Short skirt bamboo mushroom (Thai isolate); Th-DTP, and orange skirt bamboo mushroom; Or-DTP) on CCA cells. Materials and methods: CCA cell lines, including CL-6, HuCCT1, HuH28, and OUMS normal fibroblast cells, were treated with various concentrations of DTP extracts. The MTT assay was used to determine cytotoxicity, and cell morphology was observed by using phase-contrast microscopy. Results and discussion: The results suggested that Ch-DTP effectively killed all three CCA cell lines in both low (0.3 mg/mL) and high (0.6 mg/mL) doses, but Th-DTP and Or-DTP had significantly reduced cell viability only at high doses (p<0.001). Ch-DTP had the best effect by showing a response of more than 50% at a concentration of 0.3 mg/mL. Th-DTP had moderate effects at a concentration of lower than 0.6 mg/mL but worthwhile at higher concentrations, whereas Or-DTP had limited effects at concentrations of 0.4 mg/mL and downward, although the effects were significantly increased in the higher concentration range. Morphology of the Ch-DTP treated cells was greatly transformed both at low and high doses, but Th-DTP and Or-DTP showed definite alteration only at high doses. The morphological changes revealed apoptotic induction. In OUMS cells, no effects were recognized with any of the three DTPs. Conclusion: This study indicated that DTP extracts could induce cytotoxicity in cholangiocarcinoma, with a high potential of being an effective therapeutic agent. Graphical abstract: