Figure 5.

Combination of crizotinib with topo/cyclo induces downstream markers of cell death in vivo. Once tumors reached 200 mm³ mice bearing (A) SH-SY5Y and (C) Felix-PDX human neuroblastoma xenografts were treated for three consecutive days as follows: vehicle, crizotinib (Cz, 100 mg/kg, oral), topotecan (Topo, 0.05 mg/kg) and cyclophosphamide (Cyclo, 20 mg/kg) and combination of both. Tumors were harvested 4 hours post last treatment. Cell lysates were analyzed by immunoblotting with the indicated antibodies. Bands corresponding to phosphorylated-p53-ser15 (P-p53, top), cleaved caspase-3 (cc3, middle), and total ALK (bottom) of (B) SH-SY5Y and (D) Felix-PDX were quantified by densitometric analysis using the software Image J. Results are expressed as Arbitrary Units (A.U.) and were normalized against the loading control GAPDH. The bands from each treatment group were averaged and compared using an ANOVA and a Tukey’s HSD test. *p<0.05, **p<0.01, ***p<0.001.