Tissue-Specific Expression of Transfected Human Insulin Genes in Pluripotent Clonal Rat Insulinoma Lines Induced during Passage in vivo

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 85; no. 18; pp. 6652 - 6656
• Main Authors: Madsen, Ole D., Andersen, L. Christina, Michelsen, Birgitte, Owerbach, David, Larsson, Lars-Inge, Lernmark, Ake, Steiner, Donald F.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01-09-1988; National Acad Sciences
• Subjects: 550201 - Biochemistry- Tracer Techniques; Adenoma, Islet Cell - genetics; Animals; BASIC BIOLOGICAL SCIENCES; Beta cells; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BIOCHEMISTRY; BODY; C-Peptide - analysis; CELL CONSTITUENTS; CELL DIFFERENTIATION; Cell lines; Cells, Cultured; CHEMISTRY; Clone Cells; CYTOCHEMISTRY; DAYS LIVING RADIOISOTOPES; DIGESTIVE SYSTEM; DNA; DNA Restriction Enzymes - metabolism; ENDOCRINE GLANDS; Gene Expression Regulation; GENE REGULATION; GENES; GLANDS; HORMONES; Humans; HYBRIDIZATION; Hypoglycemic agents; Immunohistochemistry; INSULIN; Insulin - genetics; Insulinoma - genetics; Insulinoma - metabolism; Islet cells; ISOTOPES; LIGHT NUCLEI; NUCLEI; NUCLEIC ACIDS; ODD-ODD NUCLEI; ONTOGENESIS; ORGANIC COMPOUNDS; ORGANS; PANCREAS; Pancreatic Neoplasms - genetics; Pancreatic Neoplasms - metabolism; PEPTIDE HORMONES; Phenotypes; PHOSPHORUS 32; PHOSPHORUS ISOTOPES; PLASMIDS; Pluripotent stem cells; RADIOISOTOPES; Rats; RFLPS; Stem cells; TRANSCRIPTION; Transfection; Tumor cell line; Tumors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.18.6652

The pluripotent rat islet tumor cell line MSL-G2 expresses primarily glucagon or cholecystokinin and not insulin in vitro but changes phenotype completely after prolonged in vivo cultivation to yield small-sized hypoglycemic tumors composed almost entirely of insulin-producing beta cells. When a genomic DNA fragment containing the coding and upstream regulatory regions of the human insulin gene was stably transfected into MSL-G2 cells no measurable amounts of insulin or insulin mRNA were detected in vitro. However, successive transplantation of two transfected clones resulted in hypoglycemic tumors that efficiently coexpressed human and rat insulin as determined by human C-peptide-specific immunoreagents. These results demonstrate that cis-acting tissue-specific insulin gene enhancer elements are conserved between rat and human insulin genes. We propose that the in vivo differentiation of MSL-G2 cells and transfected subclones into insulin-producing cells reflects processes of natural beta-cell ontogeny leading to insulin gene expression.