Decreased expression of the N-myc oncogene in neuroblastoma cell lines SH-SY5Y and BE(2)-C, following treatment with retinoic acid, was paralleled by down-regulation of MRP gene expression, contrasting with increased expression of the MDR1 gene.
This study offers compelling evidence that (a) IGR-N-91 is a human neuroblastoma xenograft model able to induce metastasis in nude mice, (b) an increase in MYCN and MDR1 transcripts levels is associated with the metastatic process, and (c) IGR-N-91 provides a biological tool for the study of gene activations during tumor dissemination in neuroblastoma.
Expression of N-myc, c-myc, and MDR-1 proteins in newly established neuroblastoma cell lines: a study by immunofluorescence staining and flow cytometry.
A panel of monoclonal antibodies (MAbs) to P-glycoprotein was developed by immunization of mice with multidrug-resistant human neuroepithelioma and neuroblastoma cells.
Because expression of mdr-1 is increased in neuroblastoma cell lines by differentiating agents, the authors hypothesized a similar correlation with differentiation in vivo in neuroblastomas.
Many of the neuroblastoma samples were also evaluated for N-myc amplification but there was no correlation between N-myc copy number and the level of MDR1 mRNA expression.
MDR1 RNA levels were occasionally elevated in other untreated cancers, including neuroblastoma, acute lymphocytic leukemia (ALL) in adults, acute nonlymphocytic leukemia (ANLL) in adults, and indolent non-Hodgkin's lymphoma.