Methods for producing pancreatic precursor cells and uses thereof

A method of culturing and expanding somatic pancreatic precursor cells in vitro, comprising:

• a) twice digesting a population of pancreatic cells isolated from an intact pancreatic tissue sample obtained from a mammal, wherein said population of pancreatic cells comprises pancreatic alpha cells, pancreatic beta cells, pancreatic delta cells, pancreatic polypeptide (PP) cells, acinar cells, ductal cells, pancreatic precursor cells, mesenchymal cells, fibroblasts, or a mixture or combination thereof;
• b) culturing said population of pancreatic cells in a culture medium that permits cell growth under conditions, and for a time sufficient, to permit cell growth, wherein the culture medium comprises at least 50 μM of a guanine nucleotide precursor selected from xanthosine, xanthine, or hypoxanthine, or an analogue or derivative thereof, wherein said guanine nucleotide precursor, analogue or derivative thereof suppresses asymmetric cell kinetics, thereby allowing exponential growth and expansion of said pancreatic precursor cells.