MULTIPLE ALTERNATIVE SPLICE ISOFORMS OF PARATHYROID HORMONE-RELATED PEPTIDE MESSENGER-RNA IN HUMAN CELL-LINES

Parathyroid hormone-related peptide (PTHrP) is thought to be responsible for hypercalcemia in some patients with malignant tumors. The PTHrP gene has seven exons, giving rise to three types of PTHrP isoform through alternative splicing. We studied the expression of mRNAs in 14 human cell lines using the reverse transcription-PCR method, to examine tissue-specific expression. All the cell lines expressed at least two types of PTHrP transcript. Most cell lines expressed all four types of PTHrP mRNA isoform. However, a rhabdomyosarcoma cell line, RD, and a bladder carcinoma cell line, T24, expressed only two types. These results may suggest that PTHrP mRNA is expressed in the majority of tumor and normal tissues and that it shows less tissue- or tumor-specificity.