Papadimitropoulou, A.; Charalampous, C.; Kogionou, P.; Reinhardt, D.; Sonntag, J.; Gavalas, A.; Hofmann, M. H.; Erlmann, P.; Franti, M.; Doerr, J.; Klein, T.; Willis, G. R.; Serafimidis, I.

Clinical studies have suggested that restoring a sufficient mass of functional {beta} cells can provide an effective treatment option for diabetes, however, it remains unclear whether this can be achieved through pharmacological stimulation of endogenous {beta}-cell proliferation. We demonstrate here that ectopic expression of a constitutively active form of Kras (KrasG12D) exclusively in pancreatic endocrine cells suppresses {beta}-cell proliferation, resulting in a dramatic reduction in {beta}-cell numbers and islet size. Conversely, we demonstrate that the potent and selective SOS1-RAS interaction inhibitor BI-3406 promotes unprecedented levels of {beta}-cell proliferation in primary human islets, both in culture and following transplantation in immunocompromised diabetic mice. Importantly, using murine models of streptozotocin-induced diabetes, we show that BI-3406 treatment restores {beta}-cell mass, leading to a gradual normalization of blood glucose and insulin levels, as well as to sustainable improvement in glucose tolerance. Our data provide the first pre-clinical evidence of an orally bioavailable KRAS inhibitor that can directly induce {beta}-cell regeneration.