Post-surgery fluids promote transition of cancer stem cell- to-endothelial and AKT/mTOR activity, contributing to relapse of giant cell tumors of bone

// Flavio Fazioli 1, * , Gianluca Colella 2, * , Roberta Miceli 3 , Mariano Giuseppe Di Salvatore 1 , Michele Gallo 1 , Serena Boccella 4 , Annarosaria De Chiara 5 , Carlo Ruosi 2, * and Filomena de Nigris 6, * 1 Division of Musculoskeletal Oncology Surgery, National Cancer Institute G. Pascale, Naples, Italy 2 Department of Human Health, Federico II University of Naples, Naples, Italy 3 S.C. Cellular Biology and Biotherapy, National Cancer Institute G. Pascale, Naples, Italy 4 Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, Naples Italy 5 Division of Pathology, National Cancer Institute G. Pascale Foundation, Naples, Italy 6 Department of Biochemistry, Biophysics and General Pathology, University of Campania “Luigi Vanvitelli”, Naples Italy * These authors have contributed equally to this work Correspondence to: Filomena de Nigris, email: Filomena.denigris@unina2.it Keywords: recurrences, sarcoma, angiogenesis, stem cells, AKT Received: March 31, 2017     Accepted: May 29, 2017     Published: June 28, 2017 ABSTRACT Giant cell tumors of bone (GCTB) are rare sarcomas with a high rate of unpredictable local relapse. Studies suggest that surgical methods affect recurrence, supporting the idea that local disease develops from re-growth of residual cancer cells. To identify early prognostic markers of individual risk of recurrence, we evaluated the effect of post-surgery fluids from a cohort of GCTB patients on growth of primary and established sarcoma cell lines, and mice xenograph. Post-surgery fluids increased cell growth and enhanced expression of CD44 ++ , the principal receptor for the extracellular matrix component hyaluronan and the mesenchymal stem marker CD117 + . Cancer cells became highly invasive and tumorigenic, acquiring stemness properties, and activated AKT/mTOR pathway. Prolonged stimulation with post-surgery fluids down-regulated the mesenchymal gene TWIST1 and Vimentin protein, and transdifferentiated cells into tubule-like structures positive to the endothelial markers VE-Cadherin and CD31 + . In mice, post-surgery fluids gave rise to larger and more vascularized tumors than control, while in patients AKT/mTOR pathway activation was associated with recurrence by logistic regression (Kaplan-Meier; P<0.001). These findings indicate that post-surgery fluids are an adjuvant in mechanisms of tumor regrowth, increasing stem cell growth and AKT/mTOR activity.