Regulated and Reversible Induction of Adult Human β-Cell Replication

Induction of proliferation in adult human beta-cells is challenging. It can be accomplished by introduction of cell cycle molecules such as cyclin-dependent kinase 6 (cdk6) and cyclin D-1, but their continuous overexpression raises oncogenic concerns. We attempted to mimic normal, transient, perinatal human beta-cell proliferation by delivering these molecules in a regulated and reversible manner. Adult cadaveric islets were transduced with doxycy-cline (Dox)-inducible adenoviruses expressing cdk6 or cyclin D-1. End points were cdk6/cyclin D-1 expression and human beta-cell proliferation, survival, and function. Increasing doses of Dox led to marked dose- and time-related increases in cdk6 and cyclin D-1, accompanied by a 20-fold increase in beta-cell proliferation. Notably, Dox withdrawal resulted in a reversal of both cdk6 and cyclin D-1 expression as well as beta-cell proliferation. Re-exposure to Dox reinduced both cdk/cyclin expression and proliferation. beta-Cell function and survival were not adversely affected. The adenoviral tetracycline (tet)-on system has not been used previously to drive human beta-cell proliferation. Human beta-cells can be induced to proliferate or arrest in a regulated, reversible manner, temporally and quantitatively mimicking the transient perinatal physiological proliferation that occurs in human beta-cells. Diabetes 61:418-424, 2012