To better understand the role of the activated RET oncogene in neural crest cells, we transfected two adherent human neuroblastoma tumor cell lines with oncogenic MEN2 mutant RET cDNAs.
Transfection experiments using human neuroblastoma cells showed that the mutant RET, unlike the wild-type receptor, is constitutively phosphorylated in the absence of ligand, and thus resembles other previously characterized MEN 2A mutations.
We demonstrate that ETV5 is regulated both at the protein and mRNA levels upon ALK activation or inhibition in neuroblastoma cell lines and that this regulation precedes RET modulation.
We developed a RET mini-gene reporter system, and showed that MCS+9.7 enhanced HOXB5 trans-activation from RET promoter in human neuroblastoma SK-N-SH cells and in chick embryos.
We have also demonstrated by the in vitro premethylation of a RET promoter-chloramphenicol acetyltransferase (CAT) gene construct and transient transfection experiments into neuroblastoma cells that the transcriptional activity of the RET promoter is decreased by HpaII (5'-CCGG-3') methylation and abolished by SssI (5'-CG-3') methylation.