Differential expression and mutation of NME genes in autologous cultured human melanoma cells with different metastatic potentials.
The putative metastasis suppressor genes, NME1(nm23-1) and NME2(nm23-2), were examined in a model system we developed to approximate the dissemination of melanoma from a primary skin tumor. We utilized two autologous human melanoma cell lines, IV Cl 1 and IV Cl 3, which displayed qualitatively different metastatic phenotypes following subdermal inoculation into nude mice. Highly metastatic IV Cl 1 cells expressed approximately 5 fold lower levels of protein encoded by NME genes than non-metastatic IV Cl 3 cells. Similar differences in NME protein levels were observed in tumors induced by the two cell lines in nude mice. There were no differences in NME mRNA levels between these two cell lines, suggesting that expression of these proteins is regulated at a post-transcriptional level. We found a ser122-pro mutation in the NME2 gene of metastatic IV Cl 1 cells. A similar ser120-gly mutation in NME1 has been found in human neuroblastoma, suggesting that mutation in this region may be a general phenomenon related to tumor progression. These mutations may have functional consequences since they eliminate potential phosphorylation sites and may affect the tertiary structure of mature protein complexes.
Hamby
C V
CV
Department of Microbiology & Immunology, New York Medical College, Valhalla 10595, USA.
Mendola
C E
CE
Potla
L
L
Stafford
G
G
Backer
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002999:Clone Cells; D017931:DNA Primers; D015870:Gene Expression; D016147:Genes, Tumor Suppressor; D005998:Glycine; D006801:Humans; D008545:Melanoma / Q000235:genetics* / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D054778:NM23 Nucleoside Diphosphate Kinases; D009362:Neoplasm Metastasis; D009447:Neuroblastoma / Q000235:genetics; D009701:Nucleoside-Diphosphate Kinase / Q000096:biosynthesis / Q000235:genetics; D010641:Phenotype; D010766:Phosphorylation; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D012694:Serine; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D014158:Transcription, Genetic; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D054778:NM23 Nucleoside Diphosphate Kinases; D012333:RNA, Messenger; D014157:Transcription Factors; D012694:Serine; C517938:NME1 protein, human; C517940:NME2 protein, human; C517939:Nme1 protein, mouse; C517941:Nme2 protein, mouse; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins; D005998:Glycine