PURPOSE - We developed a measurable metastatic disease model of murine neuroblastoma.
MATERIALS AND METHODS - Murine neuroblastoma cells (C1300) were cotransfected with plasmids encoding for neomycin resistance and beta-galactosidase. Transfected cells were selected by culture in media containing gentamicin. Monoclonal and polyclonal transfected cell lines were selected from surviving colonies. Three cell lines (M1, P1 and P2) were cultured and inoculated into female A/J mice. A control group was included for analysis. Animals were sacrificed on day 18 after injection, and primary tumors and organs were assayed for beta-galactosidase activity by chemoluminescence assay. Animal livers were stained with hematoxylin and eosin for histological assessment.
RESULTS - Transfected primary tumor tissue demonstrated beta-galactosidase activity. Livers from control mice had no beta-galactosidase activity. Of the 3 cell lines tested M1 showed the highest levels of beta-galactosidase activity in liver and lung, suggesting homology with human disease. Kidneys from all experimental groups had elevated beta-galactosidase activity, suggesting that the kidney is a common metastatic site for murine neuroblastoma. Hematoxylin and eosin sections demonstrated normal livers in control mice and micrometastases in the livers of all experimental animals.
CONCLUSIONS - A novel metastatic disease model for murine 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 identify by standard histological techniques.