Figure 4. XL888 induces the regression of established M229R xenografts and is associated with increased intratumoral HSP70 expression.

A: XL888 leads to regression of M229R melanoma xenografts. M229R cells were grown until a palpable tumor had formed before being treated with XL888 thrice per week (100 mg/kg) by oral gavage. Data shows growth curves normalized to starting volumes, bar graph shows mean tumor volumes after 15 days of XL888 treatment. XL888 treatment led to significant levels of tumor regression (P=0.003). B: Heatmap showing the increase in HSP70 isoform 1 (HSP71) expression in XL888 treated (15 days, 100mg per kg) xenograft samples compared to vehicle controls. C: XL888 treatment (10 days) led to the induction of apoptosis in established M229R xenografts as measured by increased TUNEL staining (green), and was associated with the induction of BIM expression and the suppression of Mcl-1 expression.