1. Comparison of MUC-1 mucin expression in epithelial and non-epithelial cancer cell lines and demonstration of a new short variant form (MUC-1/Z).
- Author
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Oosterkamp HM, Scheiner L, Stefanova MC, Lloyd KO, and Finstad CL
- Subjects
- Astrocytoma metabolism, Base Sequence, Blotting, Northern, Breast Neoplasms metabolism, Colonic Neoplasms metabolism, Epithelium metabolism, Female, Humans, Kidney Neoplasms metabolism, Melanoma metabolism, Molecular Sequence Data, Mucins genetics, Neoplasm Proteins metabolism, Neuroblastoma metabolism, Ovarian Neoplasms metabolism, Polymerase Chain Reaction, RNA, Messenger analysis, Tumor Cells, Cultured, Mucin-1 metabolism, Mucins metabolism, Neoplasms metabolism
- Abstract
Mucins, including MUC-1, are generally considered to be products of epithelial tissues and of their tumors. To examine the possible expression of MUC-1 in other cell types, a panel of human epithelial and non-epithelial tumor cell lines was studied by reverse transcriptase polymerase chain reaction (RT-PCR), Northern blot analysis, immunocytology and radioimmunoprecipitation. Using the highly sensitive RT-PCR method, products corresponding to the non-repetitive 5' and 3' MUC-1 sequences were detected in all the cell lines examined. Amplified products lacking the tandem repeat region of MUC-1, including a new short form (designated MUC-1/Z) different from the previously reported MUC-1/Y protein, were also detected in most cell lines tested. Northern blot analysis, using a probe to the variable number tandem repeat (VNTR) region, confirmed the presence of MUC-1 mRNA in the astrocytoma, melanoma and neuroblastoma cell lines studied. MUC-1 protein was detected by immunocytology in these cell lines using monoclonal antibody (MAb) 139H2. Immunoprecipitation analysis with [3H]-glucosamine-labeled cell lysates and MAb 139H2 or an antibody to the cytoplasmic domain, CT-1, detected MUC-1 protein in 2 epithelial cell lines, an astrocytoma cell line (SK-MG-4) but not in the melanoma and neuroblastoma cell lines studied. Northern blot analysis using a probe to the 3' end of MUC-1 mRNA, confirmed the presence of MUC-1 mucin and also identified short products corresponding to the size of the short variant forms. Protein products corresponding to the MUC-1/Y and MUC-1/Z variant forms were not observed using either [3H]-glucosamine-labeled OVCAR-3 cells or [3H]-amino acid-labeled MCF-7 cells and either CT-1 antibody or MAb 232A1, detecting an epitope to the C-terminal region. Thus, depending on the sensitivity of the assay used, varying amounts of MUC-1 mRNA and protein could be detected in non-epithelial tumor cell lines. Although the amounts of MUC-1 in these cell lines are much lower than in carcinomas, it is possible that MUC-1 mucin serves a similar function in non-epithelial as in epithelial cells. The possible role of MUC-1/Y and MUC-1/Z variant forms in these cell lines is not understood.
- Published
- 1997
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