PATHOLOGY ONCOLOGY RESEARCH Vol 13, No 4, 2007 Article is available online at http:/]www.webio.hu/por/2007/13/4/0336 ARTICLE Expression of Connective Tissue Growth Factor (CTGF/CCN2) in a Mouse Model of Rhabdomyosarcomagenesis Stefania CROCI, ~Lorena LANDUZZI, 2 Giordano NICOLETTI, 2 Arianna PALLADINI, 1 Agnese ANTOGNOLI, l Carla DE GIOVANNI, 1 Patrizia NANNI, ~Pier-Luigi LOLLINI t ~Cancer Research Section, Department of Experimental Pathology, University of Bologna; 2Laboratorio di Ricerca Oncologica, Istituti Ortopedici Rizzoli, Bologna, Italy Connective tissue growth factor (CTGF/CCN2) is a cysteine-rich matricellular protein that belongs to the CCN (CYR61, CTGF, __NOV)protein family. It is highly expressed by human rhabdomyosarcoma cells and sustains their survival. In this study we investigated CCN2 expression in a mouse model of spontaneous rhabdomyosarcomagenesis that com- bines HER-2/neu oncogene activation and p53 oncosuppressor gene inactivation (BALB-p53neu mice). Murine rhabdomyosarcoma cells showed a 4- 26 fold increase in CCN2 mRNA expression regard- ing to normal thigh muscle. Moreover, they expressed CCN2 protein at levels comparable to human rhabdomyosarcoma cells. Therefore BALB- p53neu mice might be useful for the evaluation of the role played by CCN2 in rhabdomyosarcoma in vivo. (Pathology Oncology Research Vol 13, No 4, 336-339) Key words: rhabdomyosarcoma, mouse model, CCN proteins, CCN2]CTGF Introduction Connective tissue growth factor (CTGF or CCN2) belongs to the CCN family of proteins that comprises other five members: CCN1/CYR61 (cysteine-rich protein 61), CCN3]NOV (nephroblastoma overexpressed gene), CCN4/WISP-1 (Wnt-induced secreted protein-l), CCN5/WISP-2 and CCN6]WISP-3. z They are secreted, cysteine-rich, matricellular proteins that share a common modular structure of four domains: insulin-like growth factor binding domain, von Willebrand type C domain, thrombospondin-1 domain and cystine knot domain (with the exception of CCN5 that lacks the last one). 2 CCN2 has multiple biological functions, dependent on the cell type and the cellular context. It regulates cell proliferation, sur- vival, migration and differentiation, and has a role in angiogenesis, wound healing, fibrosis, chondrogenesis and osteogenesis. 8 Moreover, all CCN proteins are emerg- ing as key regulators of tumorigenesis, involved in the Received: Dec 4, 2006; accepted: Nov 10, 2007 Correspondence: Prof. Pier-Luigi LOLLINI, PhD, Section of Can- cer Research, Department of Experimental Pathology, University of Bologna, Viale Filopanti 22,1-40126, Bologna, Italy. Tel.: +39-051 - 2094786, Fax: +39-051-242169, E-mail: pierluigi.lollini@unibo.it regulation of tumor cell growth and tumor-stroma interac- tions, thus being promising targets for cancer therapy. 9 We have previously found that CCN2 might be a therapeu- tic target for human rhabdomyosarcoma, the most common soft tissue sarcoma of skeletal muscle origin in childhood. CCN2 was found highly expressed by human rhabdomyosar- coma cell lines and tumor specimens of embryonal and alve- olar histotypes. Moreover, functional studies have indicated that it sustained human rhabdomyosarcoma cell survival and myogenic differentiation in an autocrine way.3 In this study we took advantage of a mouse model of rhabdomyosarcoma- genesis established in our laboratory through the combination of HER-2/neu oncogene activation and p53 oncosuppressor gene inactivation (BALB-p53neu mice).6 We investigated whether murine rhabdomyosarcoma cells expressed CCN2 like human rhabdomyosarcoma cells making BALB-p53neu mice a suitable preclinical model for the study of the role played by CCN2 in rhabdomyosarcoma in vivo. Materials and methods Mice and cell lines BALB/c mice transgenic for the activated rat HER-2/neu oncogene under the control of the MMTV-LTR promoter and with a knockout allele for the p53 oncosuppressor gene, © 2007 Ar~nyi Lajos Foundation