(S)-CR8 is an analog of roscovitine that inhibits cyclin-dependent kinases (CDKs) 1/2/3/5/7/9; it displays anticancer, nephroprotective, and neuroprotective activities. CR8 induces apoptosis in various cancer cells by suppressing cell cycle progression. In animal models of spinal cord injury, this compound decreases neurodegeneration, cognitive decline, and microglial activation. CR8 also decreases sensorimotor deficits, cognitive deficits, and lesion volume by limiting cell cycle activation in animal models of traumatic brain injury. In animal models of polycystic kidney disease, (S)-CR8 decreases renal and hepatic cystogenesis and attenuates kidney function decline by suppressing cell cycle progression and decreasing apoptosis.