A PVP-extract fungal protein of Omphalia lapideacens and its antitumor activity on human gastric tumors and normal cells

Abstract

Abstract. Omphalia lapidescens is an important medicinal fungus as well as traditional Chinese medicine used for disease treatment. It is mainly used as a vermifuge for anthelmintic therapy, but it has not been hitherto reported to possess antitumor activity. In this study, a purified bioactive protein in O. lapidescens (pPeOp) was obtained using polyvinylpyrrolidone (PVP) followed by gel filtration chromatography. To evaluate the in vitro antitumor activity of pPeOp in human gastric tumor cells (MC-4 and SGC-7901) and normal cells (MC-1), MTT assay and FCM assay were used and the morphological changes, cell viability, cell death rate and cell apoptosis rate of MC-4, SGC-7901 and MC-1 cells were estimated. The results showed that pPeOp could significantly reduce the cell viability of MC-4 and SGC-7901 cells in a concentration-dependent manner, with IC 50 values of 236.05 and 156.28 µg/ml, respectively. The morphological observation also indicated a similar result. In FCM assays, a significant increase of cell death rate and cell apoptosis rate of the tumor cells were observed, indicating probable necrosisinducing effects and/or apoptosis-inducing effects of pPeOp. Importantly, there was no significant effect of pPeOp on MC-1 cells in each assay, showing that pPeOp has no adverse effects on the normal cells. In conclusion, pPeOp is a newly discovered bioactive protein in O. lapidescens and this is the first report on antitumor activity of such a fungal protein. This may provide a meaningful basis for developing a new protein drug for treatment against cancer, especially gastric cancer.

pPeOp from Omphalia lapidescens Schroet induces cell cycle arrest and inhibits the migration of MC-4 gastric tumor cells

“…Furthermore, the results of the wound healing assay demonstrated that pPe O p decreased the migratory rate of MC-4 cells in a concentration-dependent manner. In addition, pPe O p had a marked lethal effect on MC-4 cells, which is consistent with Chen et al (14). However, the effect of pPe O p on cell migration was not investigated by Chen et al .…”

“…The major constituent, pPe O p, was identified with relatively high chromatographic purity. pPe O p increased apoptosis in human gastric tumor cells compared with conventional Western treatments, which induce tumor cell (MC-4 and SGC-7901) death and apoptosis significantly, but also trigger minor apoptosis of normal gastric cells (MC-1) (14). To further understand the underlying molecular mechanisms of the antitumor activities of pPe O p, its effects on tumor cell migration and cell cycle progression were investigated.…”

“…Previous studies have demonstrated that O. lapidescens Schroet effectively induces tumor necrosis; consequently, the China Food and Drug Administration has approved Lei Wan Pian and Lei Wan Jiao Nang as antitumor auxiliary drugs (9,10). Research has revealed that the antitumor effects of the active ingredients from O. lapidescens Schroet are associated with certain polysaccharides and proteins (11–14), with mechanisms that include the direct killing of tumor cells through induction of apoptosis, and the enhancement of immune and anti-inflammatory responses. In a previous study (14), purified Omphalia lapidescens protein (pPe O p) was extracted from dried sclerotoids with polyvinylpyrrolidone (PVP) extraction buffer, and it was verified that a single protein band was retained following isolation of the major fraction using molecular-sieve chromatography.…”

“…Research has revealed that the antitumor effects of the active ingredients from O. lapidescens Schroet are associated with certain polysaccharides and proteins (11–14), with mechanisms that include the direct killing of tumor cells through induction of apoptosis, and the enhancement of immune and anti-inflammatory responses. In a previous study (14), purified Omphalia lapidescens protein (pPe O p) was extracted from dried sclerotoids with polyvinylpyrrolidone (PVP) extraction buffer, and it was verified that a single protein band was retained following isolation of the major fraction using molecular-sieve chromatography. The major constituent, pPe O p, was identified with relatively high chromatographic purity.…”

Antitumor activity of bacterial exopolysaccharides from the endophyte Bacillus amyloliquefaciens sp. isolated from Ophiopogon japonicus

“…The MC-4 and SGC-7901 cells were cultured as described in our previous study (38). The cultured cells collected at the stage of logarithmic growth were detached using 0.25% trypsin and their viabilities were shown to be >98%, as revealed using the Trypan blue exclusion test.…”