Lentinan, A Shiitake Mushroom ÃÂ²-Glucan, Stimulates Tumor-Specific Adaptive Immunity through PD-L1 Down-Regulation in Gastric Cancer Cells
- *Corresponding Author:
- Kenji Ina
Department of Medical Oncology, Nagoya Memorial Hospital
4-305 Hirabari, Tenpaku-ku
Nagoya, 468-8520, Japan
E-mail: [email protected]
Received date: December 05, 2016; Accepted date: December 14, 2016; Published date: December 19, 2016
Citation: Ina H, Yoneda M, Kanda M, Kodera Y, Kabeya M, et al. (2016) Lentinan, A Shiitake Mushroom β-Glucan, Stimulates Tumor-Specific Adaptive Immunity through PD-L1 Down-Regulation in Gastric Cancer Cells. Med Chem (Los Angeles) 6:710-714. doi:10.4172/2161-0444.1000419
Copyright: © 2016 Ina H, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Background: Despite the significant advances in chemotherapy, the prognosis of unresectable gastric cancer is still very poor and the role of immunotherapy remains to be clarified. We examined whether lentinan, a biological response modifier, could enhance the chemotherapeutic effects.
Materials and methods: A retrospective cohort study was conducted to evaluate the survival benefits of lentinan among the patients with gastric cancer receiving chemotherapy. To investigate the mechanisms underlying the clinical effects of lentinan, its cytotoxic activity was accessed by cell proliferation assay. The expression of molecules relevant to immune checkpoints were analyzed by real-time PCR using human gastric cancer cell lines; MKN1, MKN45, and NUGC3.
Results: The addition of lentinan prolonged the survival of patients with gastric cancer receiving S-1 based chemotherapy. Lentinan reduced the constitutive expression of PD-L1 in all cell lines mainly by suppressing the MAPK pathway.
Conclusion: Lentinan at clinical concentrations stimulates tumor-specific adaptive immunity through PD-L1 downregulation, which may enhance chemotherapy-induced tumor clearance and patient survival.