**Figure 4.** **αKlotho gene expression is stimulated by procaspase activating compound 1 (PAC-1) in MDCK and NRK-52E cells.** (**A**) Arithmetic mean ± SEM of αklotho transcript levels normalized to *TBP* in MDCK cells treated with PAC-1 at the indicated concentration for 24 h (*n* = 6; *Friedman ANOVA* followed by *Dunn-Bonferroni* post hoc test). (**B**, **C**) Arithmetic mean ± SEM of MDCK cell viability (**B**) or number (**C**) upon treatment without or with 10 μM PAC-1 for 24 h (**B**: *n* = 4, *one-sample t*-test; **C**: *n* = 6, *one-sample t*-test). (**D**) Rate of apoptosis and necrosis of MDCK cells treated with or without 10 μM PAC-1 for 24 h (*n* = 6, *one-sample t* test). (**E**) Arithmetic mean ± SEM of αklotho transcript levels relative to *TBP* in NRK-52E cells incubated without or with 10 μM PAC-1 for 24 h (*n* = 6, *paired t-*test). (**F**, **G**) Arithmetic mean ± SEM of NRK-52E cell viability (**F**) or number (**G**) upon treatment without or with 10 μM PAC-1 for 24 h (**F**: *n* = 5, *one-sample t*-test; **G**: *n* = 4, *one-sample t*-test). (**H**) Rate of apoptosis and necrosis of NRK-52E cells treated with or without 10 μM PAC-1 for 24 h (*n* = 5, *one-sample t* test). ^{*}*p* < 0.05, ^{**}*p* < 0.01, ^{***}*p* < 0.001 indicate significant difference from vehicle control; Abbreviations: a. u.: arbitrary units; ctr: control.