BETA-TC-3

Beta-TC-3 is a pancreatic β-cell line from mice, originally isolated from insulinomas that spontaneously developed in transgenic mice carrying a chimeric insulin-promoter-driven SV40 large T antigen. Beta-TC-3 retains important characteristics of the differentiated β-cell. Beta-TC-3 can be grown as an adherent, transformed, yet genetically stable cell line in culture, and has a doubling time of approximately 34 hours.

Beta-TC-3 has been shown to express and process proinsulin I and II to the same degree as mature insulin as is observed in normal islet β-cells, and secretion of insulin from Beta-TC-3 can be stimulated several fold (up to ~30-fold) by glucose, although the threshold to achieve maximum release is lower than that of primary β-cells. In addition to insulin, Beta-TC-3 also shows high expression of other pre-prohormone mRNAs, including pro-Dynorphin. Stimulation (e.g. cAMP analogues) can also induce production and secretion of opioid peptides derived from pro-Dynorphin. This feature has made Beta-TC-3 a unique cell line to study not only insulin biosynthesis and glucose-stimulated secretion, but also prohormone processing and alternative peptide production in β-cells.

Beta-TC-3 is widely used today as an in vitro system to study β-cell biology, regulation of insulin gene expression and secretory dynamics, prohormone processing, and for screening of pharmacological agents affecting β-cell function, due to its stability in growth and replicability as well as maintained β-cell functions.