Figure 10. NF1 suppression leads to ERK activation and confers resistance to ALK inhibitors in human neuroblastoma cells.

(A) NF1 knockdown confers resistance to ALK inhibitors in human neuroblastoma cells. SH-SY5Y cells expressing pRS and shGFP control vectors, or shNF1 vectors were grown in the absence or presence 50 nM NVP-TAE684 or 250 nM crizotinib. The cells were fixed, stained and photographed after 14 (untreated and crizotinib treated), or 21 (NVP-TAE684 treated) days. (B) Down-regulation of NF1 results in elevated level of phosphorylated p-ERK and p-AKT. Western blot analysis of total lysates of SH-SY5Y cells expressing pRS, shGFP or shNF1 vectors. (C) The level of NF1 knockdown by each of the RNAi vectors was measured by examining the NF1 mRNA levels by qRT-PCR. Error bars denote standard deviation.