Fig. 4: Jumonji inhibitors activate ER stress pathway proteins and trigger cell death in SCLC cells.
From: Jumonji histone demethylases are therapeutic targets in small cell lung cancer
A Western blot analysis demonstrates multiple proteins in the ER stress pathway are elevated by treatment with IC50 doses of JIB-04 or SD70 for 24 h across multiple SCLC lines representing various inhibitor sensitivities and both NEUROD1-high (H446, H2171, H524) and ASCL1-high transcription (H510, H1522, H1417, H2107) factor clusters. Tubulin or GAPDH were used as a loading control. B Activation of phospho-elF2α is also seen by Western analysis in SCLC cell lines treated with inhibitors for 24 h at their respective IC50. GAPDH was used as loading control. C Annexin V staining was analyzed by FACS after 48 h (H446, H2171, H510) or 72 h (H524) of inhibitor treatment, and double-positive early or late apoptotic cells quantified. Data are averages across replicates with error bars representing SEM. **** = p ≤ 0.0001, *** = p ≤ 0.001, ** = p ≤ 0.01, * = p < 0.05, by unpaired two-tailed t-test. D Inhibitor treatment with IC50 for 48 h triggers PARP cleavage in H510 as shown by Western blot, indicating late stage of apoptosis. GAPDH served as a loading control. C shows quantification of early apoptotic H510 cells at this time point.
