Differences in SASP and altered UPR in MIN6 and NIT1 cells following etoposide treatment. A) and B) Western blot analysis of Pro-Mmp2 (70 kDa) and cleaved/activated Mmp2 (62 kDa) on whole cell extracts from MIN6 or NIT1 cells treated with vehicle or etoposide as indicated (2 μM or 0.5 μM, respectively). Quantification shows relative Pro-Mmp2 or Cleaved Mmp2 to Actin, mean ± SD of n = 3 biological replicates. C) and D) Luminex assay of secreted SASP factors IL-6, Serpine1 and Igfbp3 in serum-free conditioned media from MIN6 or NIT1 cells treated as indicated at timepoints indicated. Data are mean ± SD from n = 3 biological replicates. E) and F) Western blot analysis of UPR mediators phosphorylated and total IRE1α, total PERK and total ATF6α in MIN6 and NIT1 cells at 72h post-treatment with etoposide (2 μM or 0.5 μM, respectively). p21 levels were used as a positive control and β-Actin was a loading control. Data are mean ± SD of n = 3 biological replicates. Asterisk on the blots indicates a non-specific band for the PERK blots. For all panels, ∗p < 0.05, ∗∗p < 0.005, ∗∗∗p < 0.0005, ns = not significant, two-tailed T-tests.