Biological Activity In vitro: HPI-4 does not directly target Smo. It counteracts the activities of endogenous Gli1 and Gli2 but does not directly act on transcription factor GLIs. HPI-4 significantly inhibited the proliferation of these neuronal progenitors, as measured by histone H3 phosphorylation (pH3) levels, It also reduced cellular levels of cyclin D1 protein and […]