Fig. 4

Underlying mechanism of radiotherapy- or chemotherapy-triggered biogenesis of cancer stem cells of solid tumors. A Volcano plots of differentially expressed genes between GCNSCs and cisplatin-induced GCSCs, doxorubicin-induced GCSCs, X-ray-induced GCSCs or the sorted GCSCs (p < 0.05). B Upregulations of APLF, EID3, EME2, NPAS2, POLN, XRCC5, XRCC6, PARP1 and NME2 genes in all the radiotherapy- and chemotherapy-treated GCNSCs. C Western blot analysis of APLF, EID3, EME2, NPAS2, POLN, XRCC5, XRCC6, PARP1 and NME2 proteins in GCNSCs with or without radiotherapy and chemotherapy (cisplatin, doxorubicin and X-ray treatments). β-tubulin was used as a control. D The biological function annotation of APLF, EID3, EME2, NPAS2 and POLN via the Universal Protein Resource (https://www.uniprot.org/) database. E Correlation analysis of stem-associated gene expression patterns between GCSCs, GCNSCs and cisplatin-induced, doxorubicin-induced or X-ray-induced GCSCs by Spearman correlation test. The strong positive correlation was reflected by Spearman correlation coefficient ranging from 0.6 to 1.0. F Correlation analysis of DNA repair gene expression patterns in the sorted GCSCs, cisplatin-induced GCSCs, doxorubicin-induced GCSCs and X-ray-induced GCSCs by Spearman correlation test