HES1 and cancer: More evidence of the beneficial effects of concomitant Notch inhibition in overcoming gemcitabine resistance was observed also in vitro, as the co-culture of pancreatic cancer cell lines with pancreatic stellate cells conferred chemoresistance to gemcitabine to cancer cells, while the GSI L1790 or HES1 knockdown reversed the stroma-induced drug resistance [583].