Mutational activation of the MAP3K8 protooncogene in lung cancer.
The MAP3K8 protooncogene (Cot/Tpl-2) activates the MAP kinase, SAP kinase, and NF-kappaB signaling pathways. MAP3K8 mutations occur in the rat homologue, but activating mutations have yet to be identified in primary human tumors. We have identified MAP3K8 as a transforming gene from a human lung adenocarcinoma and characterized a 3' end mutation in the cDNA. In addition, we confirmed that the mutation occurs in the original lung tumor, and we screened a series of lung cancer cell lines to determine whether the MAP3K8 mutation is a common occurrence in lung tumorigenesis. The oncogene was isolated and identified with the NIH3T3 nude mouse tumorigenicity assay and cDNA library screening. The gene was analyzed by polymerase chain reaction (PCR), single-strand conformational polymorphism (SSCP), and 3'RACE for mutations. The mutation was localized to MAP3K8 exon 8 and confirmed in the primary tumor DNA. Both wild-type and mutant MAP3K8 cDNAs transformed NIH3T3 cells, but the transforming activity of the mutant was much greater than that of the wild type. PCR-SSCP screening of cell line cDNAs identified one silent polymorphism in cell line SK-LU-1. Although we were unable to find additional activating mutations, these data support a role for MAP3K8 activity in cellular transformation, but suggest that mutational activation of the gene is a rare event in lung cancer.
Laboratory of Cellular Carcinogenesis and Tumor Promotion, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
Adam Michael
AM
Clark
Steven H
SH
Reynolds
Marshall
M
Anderson
Jonathan S
JS
Wiest
D000230:Adenocarcinoma / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics*; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013964:Thyroid Neoplasms / Q000235:genetics; D014183:Transplantation, Heterologous
D017931:DNA Primers; D011518:Proto-Oncogene Proteins; D020930:MAP Kinase Kinase Kinases; C069937:MAP3K8 protein, human