EARLY CHARACTERIZATION OF A NOVEL METASTATIC DISEASE-MODEL OF MURINE NEUROBLASTOMA

Purpose: We developed a measurable metastatic disease model of murine neuroblastoma. Materials and Methods: Murine neuroblastoma cells (C130 0) were cotransfected with plasmids encoding for neomycin resistance a nd beta-galactosidase. Transfected cells were selected by culture in m edia containing gentamicin. Monoclonal and polyclonal transfected cell lines were selected hom surviving colonies. Three cell lines (M1, P1 and P2) were cultured and inoculated into female A/J mice. A control g roup was included for analysis. Animals were sacrificed on day 18 afte r injection, and primary tumors and organs were assayed for beta-galac tosidase activity by chemoluminescence assay. Animal livers were stain ed with hematoxylin and eosin for histological assessment. Results: Tr ansfected primary tumor tissue demonstrated beta-galactosidase activit y. Livers from control mice had no beta-galactosidase activity. Of the 3 cell lines tested M1 showed the highest levels of beta-galactosidas e activity in liver and lung, suggesting homology with human disease. Kidneys from all experimental groups had elevated beta-galactosidase-a ctivity, suggesting that the kidney is a common metastatic site for mu rine neuroblastoma. Hematoxylin and eosin sections demonstrated normal livers in control mice and micrometastases in the livers of all exper imental animals. Conclusions: A novel metastatic disease model for mur ine neuroblastoma has been developed. By transfecting tumor cells with genetic material encoding 2 marker proteins distant metastases may be detected by assay for beta-galactosidase or cells can be selected for neomycin resistance, even at a stage when they are difficult to ident ify by standard histological techniques.