Research Paper Volume 13, Issue 3 pp 3554—3572

ESRP1 regulates alternative splicing of CARM1 to sensitize small cell lung cancer cells to chemotherapy by inhibiting TGF-β/Smad signaling

CARM1 activates TGF-β/Smad signaling pathway by regulating arginine methylation of Smad7. (A) Co-IP assays were conducted with specific CARM1 antibody and Smad7 antibody in H69AR cells. (B) H69AR cells were treated with 5 μM ADOX for 48 hours, then cells were exposed to cisplatin or etoposide for 24 hours, and IC50 values were measured by CCK8 assays. (C) Comparison of the basic morphology of chemosensitive cells and chemoresistant cells by optical microscope. (D) Immunofluorescence staining shows the expression of EMT marker protein. (E) The expression of ESRP1, Smad3, p-Smad3 and EMT-related proteins in stably upregulated or downregulated SCLC cells was detected by western blot assay. (F) Overexpressed CARM1FL or CARM1ΔE15 in H69 and H446 cells or treated cells with ADOX for 48 hours, western blot assay was performed to detect the expression of tag antibodies, Smad3, p-Smad3 and EMT-related proteins. (G) Overexpressed CARM1FL or CARM1ΔE15 in ESRP1-upregulated H69AR and H446DDP cells or treated cells with ADOX for 48 hours, western blot assay was performed to detect the expression of tag antibodies, Smad3, p-Smad3 and EMT-related proteins. *, pp p p

Figure 6. CARM1 activates TGF-β/Smad signaling pathway by regulating arginine methylation of Smad7. (A) Co-IP assays were conducted with specific CARM1 antibody and Smad7 antibody in H69AR cells. (B) H69AR cells were treated with 5 μM ADOX for 48 hours, then cells were exposed to cisplatin or etoposide for 24 hours, and IC50 values were measured by CCK8 assays. (C) Comparison of the basic morphology of chemosensitive cells and chemoresistant cells by optical microscope. (D) Immunofluorescence staining shows the expression of EMT marker protein. (E) The expression of ESRP1, Smad3, p-Smad3 and EMT-related proteins in stably upregulated or downregulated SCLC cells was detected by western blot assay. (F) Overexpressed CARM1FL or CARM1ΔE15 in H69 and H446 cells or treated cells with ADOX for 48 hours, western blot assay was performed to detect the expression of tag antibodies, Smad3, p-Smad3 and EMT-related proteins. (G) Overexpressed CARM1FL or CARM1ΔE15 in ESRP1-upregulated H69AR and H446DDP cells or treated cells with ADOX for 48 hours, western blot assay was performed to detect the expression of tag antibodies, Smad3, p-Smad3 and EMT-related proteins. *, p<0.05; **, p <0.01; ***, p <0.001; ****, p <0.0001.