Michela Pasello1, Anna Maria Giudice2,3,4, Camilla Cristalli2, Maria Cristina Manara2, Caterina Mancarella2, Alessandro Parra2, Massimo Serra2, Giovanna Magagnoli5, Florencia Cidre-Aranaz6,7, Thomas G P Grünewald6,7,8, Carla Bini9, Pier-Luigi Lollini4, Alessandra Longhi10, Davide Maria Donati11,12, Katia Scotlandi13,14. 1. Experimental Oncology Laboratory, IRCCS Istituto Ortopedico Rizzoli, Bologna, 40136, Italy. michela.pasello@ior.it. 2. Experimental Oncology Laboratory, IRCCS Istituto Ortopedico Rizzoli, Bologna, 40136, Italy. 3. Alma Mater Institute On Healthy Planet - Alma Healthy Planet, University of Bologna, Bologna, Italy. 4. Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, Italy. 5. Department of Pathology, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. 6. Division of Translational Pediatric Sarcoma Research, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany. 7. Hopp-Children's Cancer Center (KiTZ), Heidelberg, Germany. 8. Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany. 9. Laboratory of Forensic Genetics, Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy. 10. Osteoncologia, Sarcomi dell'osso e dei Tessuti Molli e Terapie Innovative, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. 11. Unit of 3rd Orthopaedic and Traumatologic Clinic Prevalently Oncologic, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. 12. Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy. 13. Experimental Oncology Laboratory, IRCCS Istituto Ortopedico Rizzoli, Bologna, 40136, Italy. katia.scotlandi@ior.it. 14. Alma Mater Institute On Healthy Planet - Alma Healthy Planet, University of Bologna, Bologna, Italy. katia.scotlandi@ior.it.
Abstract
PURPOSE: The relevance of the subfamily A members of ATP-binding cassette (ABCA) transporters as biomarkers of risk and response is emerging in different tumors, but their mechanisms of action have only been partially defined. In this work, we investigated their role in Ewing sarcoma (EWS), a pediatric cancer with unmet clinical issues. METHODS: The expression of ABC members was evaluated by RT-qPCR in patients with localized EWS. The correlation with clinical outcome was established in different datasets using univariate and multivariate statistical methods. Functional studies were conducted in cell lines from patient-derived xenografts (PDXs) using gain- or loss-of-function approaches. The impact of intracellular cholesterol levels and cholesterol lowering drugs on malignant parameters was considered. RESULTS: We found that ABCA6, which is usually poorly expressed in EWS, when upregulated became a prognostic factor of a favorable outcome in patients. Mechanistically, high expression of ABCA6 impaired cell migration and increased cell chemosensitivity by diminishing the intracellular levels of cholesterol and by constitutive IGF1R/AKT/mTOR expression/activation. Accordingly, while exposure of cells to exogenous cholesterol increased AKT/mTOR activation, the cholesterol lowering drug simvastatin inhibited IGF1R/AKT/mTOR signaling and prevented Ser166 phosphorylation of MDM2. This, in turn, favored p53 activation and enhanced pro-apoptotic effects of doxorubicin. CONCLUSIONS: Our study reveals that ABCA6 acts as tumor suppressor in EWS cells via cholesterol-mediated inhibition of IGF1R/AKT/MDM2 signaling, which promotes the pro-apoptotic effects of doxorubicin and reduces cell migration. Our findings also support a role of ABCA6 as biomarker of EWS progression and sustains its assessment for a more rational use of statins as adjuvant drugs.
PURPOSE: The relevance of the subfamily A members of ATP-binding cassette (ABCA) transporters as biomarkers of risk and response is emerging in different tumors, but their mechanisms of action have only been partially defined. In this work, we investigated their role in Ewing sarcoma (EWS), a pediatric cancer with unmet clinical issues. METHODS: The expression of ABC members was evaluated by RT-qPCR in patients with localized EWS. The correlation with clinical outcome was established in different datasets using univariate and multivariate statistical methods. Functional studies were conducted in cell lines from patient-derived xenografts (PDXs) using gain- or loss-of-function approaches. The impact of intracellular cholesterol levels and cholesterol lowering drugs on malignant parameters was considered. RESULTS: We found that ABCA6, which is usually poorly expressed in EWS, when upregulated became a prognostic factor of a favorable outcome in patients. Mechanistically, high expression of ABCA6 impaired cell migration and increased cell chemosensitivity by diminishing the intracellular levels of cholesterol and by constitutive IGF1R/AKT/mTOR expression/activation. Accordingly, while exposure of cells to exogenous cholesterol increased AKT/mTOR activation, the cholesterol lowering drug simvastatin inhibited IGF1R/AKT/mTOR signaling and prevented Ser166 phosphorylation of MDM2. This, in turn, favored p53 activation and enhanced pro-apoptotic effects of doxorubicin. CONCLUSIONS: Our study reveals that ABCA6 acts as tumor suppressor in EWS cells via cholesterol-mediated inhibition of IGF1R/AKT/MDM2 signaling, which promotes the pro-apoptotic effects of doxorubicin and reduces cell migration. Our findings also support a role of ABCA6 as biomarker of EWS progression and sustains its assessment for a more rational use of statins as adjuvant drugs.
Authors: Pieter Goossens; Juan Rodriguez-Vita; Anders Etzerodt; Marion Masse; Olivia Rastoin; Victoire Gouirand; Thomas Ulas; Olympia Papantonopoulou; Miranda Van Eck; Nathalie Auphan-Anezin; Magali Bebien; Christophe Verthuy; Thien Phong Vu Manh; Martin Turner; Marc Dalod; Joachim L Schultze; Toby Lawrence Journal: Cell Metab Date: 2019-03-28 Impact factor: 27.287
Authors: Jill P Ginsberg; Pamela Goodman; Wendy Leisenring; Kirsten K Ness; Paul A Meyers; Suzanne L Wolden; Stephanie M Smith; Marilyn Stovall; Sue Hammond; Leslie L Robison; Kevin C Oeffinger Journal: J Natl Cancer Inst Date: 2010-07-23 Impact factor: 11.816