These findings support a hypothetical model of arnidiol-mediated apoptosis in cancer cells in which arnidiol-induced ROCK1 activation represents a primary event resulting in the dephosphorylation of Drp1 (Ser637) and cofilin (Ser3), leading, in turn, to the mitochondrial translocation of Drp1 and cofilin and culminating in mitochondrial fission and apoptosis. The gene discussed is ROCK1; the disease is cancer.