CASP9 and amyotrophic lateral sclerosis: Compared to the control cells, incubation of HT29 cells with ALS at 1 and 5 μM resulted in a 2.2- and 2.3-fold increase in the level of cleaved caspase 3, a 2.0- and 1.7-fold rise in the level of cleaved caspase 9, and a 4.4- and 5.3-fold elevation in the level of cleaved PARP, respectively (p < 0.01; Figure 5A and Figure S5A).