Potent antiproliferative and pro-apoptotic effects of a soluble protein fraction from culinary-medicinal mushroom Lentinus tigrinus on cancer cells

Lentinus tigrinus is a culinary-medicinal mushroom that possesses nutritious substances and biological activities. This study for the first time reports the anticancer potentiality of a soluble protein fraction of L. tigrinus (designated as LTPp) precipitated with polyethylene glycol 6000 on MCF-7 and PC3 cancerous cell lines. The findings of antiproliferation assays revealed that LTPp caused significant inhibitory effects at concentrations less than 1000 mu g/mL on both cell lines. Further microscopic observations confirmed obvious morphological changes caused by LTPp in both cell lines. While LTPp generated an IC50 value of 193.5 +/- 25 mu g/mL in MCF-7 cells, it was 33.60 +/- 9.0 mu g/mL in PC3 cells. In addition, the mode of cell death detected by co-staining of V-FITC/PI indicated that LTPp at 70 mu g/mL killed approximately 45.00 and 70.00% of MCF-7 and PC3 cells, respectively, through inducing apoptosis in these cells after 6 h of treatment. Altogether, LTPp showed greater antiproliferative and cytotoxic activities against PC3 cells compared with MCF-7 cells (p <= 0.05). The data presented here suggest that the LTPp fraction may be considered as a potent anticancer compound, which promisingly warrants further studies to isolate and identify active single protein/peptides.