1 u03bcm fig3 co treatment of sk ptch1 luc e6 e7 cells with purmorphamine and gdc 0449 led to the inhibition of the luciferase activity fig5 under these circumstances the ic50 of gdc 0449 was determined at 0 2 u03bcm we have developed an immortalized human cell line of keratinocytes that respond to activation by an agonist purmorphamine and inhibition of the activation by an antagonist gdc 0449 of the shh ptch signaling pathway the ec50 and ic50 demonstrate the relevance of this new tool sk ptch1 luc e6 e7 cells do not need to be cultured in the presence of feeder cells they can be expanded in a simple defined medium and they can grow easily due to immortalization this tool is used in high throughput screening hts to evaluate the efficacy of anti tumoral molecules specifically targeting inappropriate activation of the shh ptch pathway occurring in bcc but also in numerous non bcc cancers such as the cellular characteristics allow us to develop hts screening with virtually no limitation in the numbers of analysed wells arnaudeau begard c brellier f chevallier lagente o hoeijmakers j h bernerd f sarasin a and magnaldo t 2003 genetic correction of dna.