TY - JOUR T1 - Sphere-derived Prostate Cancer Stem Cells Are Resistant to γδ T Cell Cytotoxicity JF - Anticancer Research JO - Anticancer Res SP - 5481 LP - 5487 DO - 10.21873/anticanres.14559 VL - 40 IS - 10 AU - MASATSUGU MIYASHITA AU - MAKO TOMOGANE AU - YUICHI NAKAMURA AU - TERUKI SHIMIZU AU - ATSUKO FUJIHARA AU - OSAMU UKIMURA AU - EISHI ASHIHARA Y1 - 2020/10/01 UR - http://ar.iiarjournals.org/content/40/10/5481.abstract N2 - Background/Aim: γδ T cells mediate cytotoxicity against prostate cancer (PCa) cells in vitro; however, the clinical efficacy of γδ T cell-targeted immunotherapy for recurrent and metastatic PCa is unsatisfactory. We hypothesized that the resistance of recurrent and metastatic PCa to γδ T cells is related to the presence of prostate cancer stem cells (PCSCs), and we examined their relationship. Materials and Methods: PCa spheres (prostaspheres) were generated from five PCa cell lines, and their susceptibility to cytotoxicity by γδ T cells was investigated. Expression of stemness-related markers was evaluated by qRT-PCR. Results: Prostasphere-derived cancer cells were resistant to lysis by γδ T cells and expressed higher levels of several stemness markers, including CD133, NANOG, SOX2, and OCT4, than the parental PCa cell lines. Conclusion: Ex vivo-expanded γδ T cells are not effective against PCSCs. ER -