ABSTRACT
We have been studying anticancer effect of Maitake D-fraction (PDF), isolated from maitake mushroom, on various cancer cells in the past 24 years. PDF was highly effective on those cells, profoundly reducing their cell viability. However, we have not yet examined PDF on other cancer cells, particularly pancreatic, cervical, and small-cell lung cancer cells, which had been known to be dismal and deadly. Hence, we investigated if PDF alone or its combination with vitamin C (VC) might have a significant anticancer effect against those cancer cells. Pancreatic cancer AsPC-1, cervical cancer HT-3, and small-cell lung cancer H69AR cells, were treated with PDF or the combination of PDF and VC for 72 or 96 h and cell viability was determined to assess anticancer effect. The potential anticancer mechanism was also explored, focusing on glycolysis, chromatin structure, and apoptosis. A dose-dependent study showed that ≥30 μg/ml, ≥50 μg/ml, and ≥50 μg/ml of PDF led to the significant reduction in cell viability of AsPC-1, HT-3, and H69AR cells, respectively – the greater cell viability reduction is indicative of the greater anticancer effect. When these cancer cells were treated with the combination of PDF and VC with their ineffective/negligeable concentrations, their cell viability was more profoundly reduced, demonstrating a synergistic potentiation. Moreover, such a potentiation was primarily associated with increased oxidative stress (OXS), glycolysis inhibition, chromatin modifications, and ultimate apoptosis. In conclusion, the present study demonstrates anticancer effect of PDF and its synergistic potentiation with VC against AsPC-1, HT-3, and H69AR cells. Particularly, the enhancement of anticancer effect with the PDF/VC combination is rather extraordinary, accompanied by alterations in the essential cellular events. Therefore, PDF alone or its combination with VC may have some clinical implications in patients with various cancers.