Imidazo[1,2-a]pyridine Derivatives as Aldehyde Dehydrogenase Inhibitors: Novel Chemotypes to Target Glioblastoma Stem Cells.

Glioblastoma multiforme (GBM) is the deadliest form of brain tumour. It is known for its ability to escape the therapeutic options available to date, thanks to the presence of a subset of cells endowed with stem-like properties and able to resist to cytotoxic treatments. As the cytosolic enzyme aldehyde dehydrogenase 1A3 turns out to be overexpresses in this kind of cells, playing a key role for their vitality, treatments targeting this enzyme may represent a successful strategy to fight GBM. In this work we describe a novel class of imidazo[1,2-a]pyridine derivatives as aldehyde dehydrogenase 1A3 inhibitors, reporting the evidence of their significance as novel drug candidates for the treatment of GBM. Besides showing an interesting functional profile, in terms of activity against the target enzyme and selectivity toward highly homologous isoenzymes, representative examples of the series showed also a nanomolar to picomolar efficacy against patient-derived GBM stem-like cells, thus proving the concept that targeting aldehyde dehydrogenase might represent a novel and promising way to combat GBM by striking its ability to divide immortally.