Pleurotus highking Mushroom Induces Apoptosis by Altering the Balance of Proapoptotic and Antiapoptotic Genes in Breast Cancer Cells and Inhibits Tumor Sphere Formation.

Background and objectives: Mushrooms that have medicinal properties are part of many traditional diets. The aim of the present study was to use the human breast cancer cell line MCF-7 to investigate the anticancer activity of Pleurotus highking mushroom purified extract fraction-III (PEF-III) and to elucidate the possible mechanism of that activity. Materials and Methods: The effects of PEF-III on cell proliferation and viability were evaluated by a colony formation assay and an MTT assay, respectively. Cell morphological changes, annexin-V phycoerythrin and propidium iodide (PI) staining, DNA fragmentation, and caspase 3/7 activity assays were performed to determine the induction of apoptosis by PEF-III. The genes responsible for regulation of apoptosis were analyzed by means of Western blot analysis. In vitro tumor sphere formation assay was performed using a 3D sphere culture system. Results: PEF-III significantly reduced the proliferation and viability of MCF-7 cells. Cell shrinkage and rounding, and annexin-V phycoerythrin and PI staining followed by flow cytometry indicated that the cell death was due to apoptosis. Additionally, a laddering DNA pattern and increased levels of caspase-3/7 enzyme also corroborated the notion of apoptosis-mediated cell death. This incidence was further confirmed by upregulation of proapoptotic genes (p53 and its target gene, Bax) and downregulation of the expression of an antiapoptotic gene (Bcl-2). PEF-III also reduced the size and number of the tumor spheres in 3D culture conditions. Conclusions: The anticancer activity of PEF-III is due to induction of apoptosis by a shift in the balance of proapoptotic and antiapoptotic genes. Therefore, the findings of the present study may open a path to exploring potential drug candidates from the P. highking mushroom for combating breast cancer.

Antibacterial activities of actinomycete isolates collected from soils of rajshahi, bangladesh.

This study was performed to isolate actinomycete colonies having antibacterial activity from soil samples collected from different places around Rajshahi, Bangladesh. Thirty actinomycete colonies were isolated in pure culture from five soil samples using Starch-casein-nitrate-agar medium. The isolates were grouped in five color series based on their aerial mycelia color and screened for their antibacterial activity against a range of test bacteria. Sixteen isolates (53.3%) were found to have moderate to high activity against four gram-positive and four gram-negative bacteria. Since many isolates showed inhibitory activity against indicator bacteria, it is suggestive that Bangladeshi soil could be an interesting source to explore for antibacterial secondary metabolites.