Fig. 4: EPO and NGF protect NB cells from anticancer drugs.

a Experiment design for studying growth factor-induced cell survival. NB cells were treated for 72 h with drugs with/without growth factors (GF) for 72 h, then growth media was changed, new drugs and GFs added in the same concentrations, and cell viability measured after another 72 h. Drug action on cell survival in absence of GF is shown in Fig. S7a, drug concentrations are provided in Table S9. b Growth factor-induced cell survival for NB cells treated with anticancer drugs. Each dot represents mean viability fold change for a particular cell line treated with the drug in combination with 100 ng/ml GF compared to cells treated with the drug alone. Each experiment for each cell line and drug/GF combination was performed in triplicates. Mean changes in cell viability for all six NB cell lines treated with drug/GF combination were compared with cells treated with DMSO and GF. Mean and SD values are shown, Friedman test was used to determine statistically significant differences. *p value < 0.05; **<0.01; ***<0.001; ****<0.0001. c Heatmaps of gene expression fold changes in NB cells treated with imatinib, dasatinib, crizotinib, and vincristine compared to cells treated with DMSO (mock treatment). Expression changes were measured by real-time PCR. d Staining with anti-EPOR and anti-TrkA antibodies of SH-SY5Y and SK-N-BE cells after imatinib treatment for 72 h and measured by flow cytometry. Each experiment was performed in triplicate, the most representative histograms are shown, p values are calculated by a two-sided t test. e Pearson correlations of GF-induced protective effect and receptors expression change in drug-treated NB cells.