Figure 2. ESRP1 is reduced in chemoresistant SCLC cells and inhibits chemoresistance of SCLC in vitro. (A) IC50 values of cisplatin and etoposide in SCLC cells. (B) Differential expression of ESRP1 in SCLC chemoresistant cells (H69AR and H446DDP) and chemosensitive cells (H69 and H446) at transcriptional level. (C) Differential expression of ESRP1 in SCLC chemoresistant cells (H69AR and H446DDP) and chemosensitive cells (H69 and H446) at translational level. (D) Detection of ESRP1 up-regulation efficiency in H69AR and H446DDP cells at the transcriptional level and translational level. (E) CCK8 assay to detect IC50 value of cisplatin and etoposide after overexpressing ESRP1 in H69AR and H446DDP cells. (F) Cells apoptosis was analyzed by flow cytometry after treatment with cisplatin and etoposide for 24 hours in ESRP1 overexpressed cells. (G) Cells cycle arrest was analyzed by flow cytometry after treatment with cisplatin and etoposide for 24 hours in ESRP1overexpressed cells. (H) Detection of ESRP1 down-regulation efficiency in H69 and H446 cells at the transcriptional level and translational level. (I) CCK8 assay to detect IC50 value of cisplatin and etoposide after down-regulation of ESRP1 in H69 and H446 cells. (J) Cell apoptosis was analyzed by flow cytometry after treatment with cisplatin and etoposide for 24 hours in ESRP1-downregulated cells. (K) Cells cycle arrest was analyzed by flow cytometry after treatment with cisplatin and etoposide for 24 hours in ESRP1-downregulated cells. *, p<0.05; **, p <0.01; ***, p <0.001; ****, p <0.0001.