Fig. 4.

Analysis of P2X receptor expression profile in human ESCC cell lines. Expression of purinergic receptors P2X1–7 in KYSE30, KYSE450, and OE21 cells lines by RT-PCR (a). GAPDH expression was used as reference gene. RT-qPCR analysis of P2X7R relative expression was performed, and the values were shown as ΔCq relative expression in relation to GAPDH in EPC2, KYSE30, KYSE450, and OE21 cell lines (b) and the significance was described as *p < 0.05 and *** p < 0.001 indicating difference in relation to KYSE450. Representative Western blotting assays showing positivity to P2X7R in EPC2, KYSE30, KYSE450, and KYSE520 cells (c). Relative P2X7R levels obtained by analysis of protein bands detected by Western blot were compared to GAPDH expression levels (d) and the significance was described as *p < 0.05 and *** p < 0.001 indicating difference in relation to EPC2. Each column represents the mean ± SEM and the experiments were performed three times in triplicate