HUI-HSIN KOPeng, Hsin HuiHsin HuiPengCheng, An NingAn NingChengHAN-YI E. CHOUHSIN-HAN HOUWEI-TING KUOWEI-WEN LIUYEN-PING KUOLee, Alan Yueh LuenAlan Yueh LuenLeeSHIH-JUNG CHENG2024-01-122024-01-122023-10-0113479032https://scholars.lib.ntu.edu.tw/handle/123456789/638452The suppressive regulatory T cells (Treg) are frequently upregulated in cancer patients. This study aims to demonstrate the hypothesis that arecoline could induce the secretion of mitochondrial (mt) DNA D-loop and programmed cell death-ligand 1 (PD-L1) in extracellular vesicles (EVs), and attenuate T-cell immunity by upregulated Treg cell numbers. However, the immunosuppression could be reversed by whole glucan particle (WGP) β-glucan in oral squamous cell (OSCC) patients. Arecoline-induced reactive oxygen specimen (ROS) production and cytosolic mtDNA D-loop were analyzed in OSCC cell lines. mtDNA D-loop, PD-L1, IFN-γ, and Treg cells were also identified for the surgical specimens and sera of 60 OSCC patients. We demonstrated that higher mtDNA D-loop, PD-L1, and Treg cell numbers were significantly correlated with larger tumor size, nodal metastasis, advanced clinical stage, and areca quid chewing. Furthermore, multivariate analysis confirmed that higher mtDNA D-loop levels and Treg cell numbers were unfavorable independent factors for survival. Arecoline significantly induced cytosolic mtDNA D-loop leakage and PD-L1 expression, which were packaged by EVs to promote immunosuppressive Treg cell numbers. However, WGP β-glucan could elevate CD4+ and CD8+ T-cell numbers, mitigate Treg cell numbers, and promote oral cancer cell apoptosis. To sum up, arecoline induces EV production carrying mtDNA D-loop and PD-L1, and in turn elicits immune suppression. However, WGP β-glucan potentially enhances dual effects on T-cell immunity and cell apoptosis and we highly recommend its integration with targeted and immune therapies against OSCC.enextracellular vesicle | mitochondrial DNA D-loop | oral squamous cell carcinoma | programmed cell death-ligand 1 | whole glucan particle β-glucan[SDGs]SDG3journal article10.1111/cas.15919375255612-s2.0-85166556924https://api.elsevier.com/content/abstract/scopus_id/85166556924