PT - JOURNAL ARTICLE AU - Rosaria A. Fontanella AU - Silvia Sideri AU - Chiara Di Stefano AU - Angiolina Catizone AU - Silvia Di Agostino AU - Daniela F. Angelini AU - Gisella Guerrera AU - Luca Battistini AU - Giulia Battafarano AU - Andrea Del Fattore AU - Antonio Francesco Campese AU - Fabrizio Padula AU - Paola De Cesaris AU - Antonio Filippini AU - Anna Riccioli TI - CD44v8-10 is a marker for malignant traits and a potential driver of bone metastasis in a subpopulation of prostate cancer cells AID - 10.20892/j.issn.2095-3941.2020.0495 DP - 2021 Aug 01 TA - Cancer Biology and Medicine PG - 788--807 VI - 18 IP - 3 4099 - http://www.cancerbiomed.org/content/18/3/788.short 4100 - http://www.cancerbiomed.org/content/18/3/788.full SO - Cancer Biol Med2021 Aug 01; 18 AB - Objective: Bone metastasis is a clinically important outcome of prostate carcinoma (PC). We focused on the phenotypic and functional characterization of a particularly aggressive phenotype within the androgen-independent bone metastasis-derived PC3 cell line. These cells, originated from the spontaneous conversion of a CD44-negative subpopulation, stably express the CD44v8-10 isoform (CD44v8-10pos) and display stem cell-like features and a marked invasive phenotype in vitro that is lost upon CD44v8-10 silencing.Methods: Flow cytometry, enzyme-linked immunoassay, immunofluorescence, and Western blot were used for phenotypic and immunologic characterization. Real-time quantitative polymerase chain reaction and functional assays were used to assess osteomimicry.Results: Analysis of epithelial–mesenchymal transition markers showed that CD44v8-10pos PC3 cells surprisingly display epithelial phenotype and can undergo osteomimicry, acquiring bone cell phenotypic and behavioral traits. Use of specific siRNA evidenced the ability of CD44v8-10 variant to confer osteomimetic features, hence the potential to form bone-specific metastasis. Moreover, the ability of tumors to activate immunosuppressive mechanisms which counteract effective immune responses is a sign of the aggressiveness of a tumor. Here we report that CD44v8-10pos cells express programmed death ligand 1, a negative regulator of anticancer immunity, and secrete exceptionally high amounts of interleukin-6, favoring osteoclastogenesis and immunosuppression in bone microenvironment. Notably, we identified a novel pathway activated by CD44v8-10, involving tafazzin (TAZ) and likely the Wnt/TAZ axis, known to play a role in upregulating osteomimetic genes.Conclusions: CD44v8-10 could represent a marker of a more aggressive bone metastatic PC population exerting a driver role in osteomimicry in bone. A novel link between TAZ and CD44v8-10 is also shown.