acy-1215 and Cognitive-Dysfunction

Chemotherapy-related cognitive impairment (CRCI) is a potential long-term side effect during cancer treatment. There are currently no effective treatments for CRCI. Reduction or inhibition of histone deacetylase 6 (HDAC6) has been considered a possible therapeutic strategy for cognitive deficits. HDAC6 inhibition recently has been shown to reverse chemotherapy-induced peripheral neuropathy effectively. In the present study, we examined the effect of HDAC6 inhibitor ACY-1215 (Ricolinostat) on cisplatin-induced brain damage and cognitive deficits in mice. Our results showed that ACY-1215 ameliorated behavioral deficits and dendritic spine loss and increased synaptic density in cisplatin-treated mice. Mechanistically, HDAC6 inhibitor ACY-1215 enhanced α-tubulin acetylation in the hippocampus of cisplatin-treated mice. Furthermore, ACY-1215 recovered cisplatin-induced impaired mitochondrial transport and mitochondrial dysfunction in the hippocampus. Our results suggest that inhibition of HDAC6 improves established cisplatin-induced cognitive deficits by the restoration of mitochondrial and synaptic impairments. These results offer prospective approaches for CRCI, especially because ACY1215 currently serves as an add-on cancer therapy during clinical trials.

Topics: Animals; Cisplatin; Cognitive Dysfunction; Dendritic Spines; Hippocampus; Histone Deacetylase 6; Histone Deacetylase Inhibitors; Hydroxamic Acids; Male; Mice, Inbred C57BL; Mitochondria; Neuroprotective Agents; Pyrimidines

Chemotherapy-induced cognitive impairment (CICI) is a commonly reported neurotoxic side effect of chemotherapy, occurring in up to 75% cancer patients. CICI manifests as decrements in working memory, executive functioning, attention, and processing speed, and greatly interferes with patients' daily performance and quality of life. Currently no treatment for CICI has been approved by the US Food and Drug Administration. We show here that treatment with a brain-penetrating histone deacetylase 6 (HDAC6) inhibitor for two weeks was sufficient to fully reverse cisplatin-induced cognitive impairments in male mice, as demonstrated in the Y-maze test of spontaneous alternation, the novel object/place recognition test, and the puzzle box test. Normalization of cognitive impairment was associated with reversal of cisplatin-induced synaptosomal mitochondrial deficits and restoration of synaptic integrity. Mechanistically, cisplatin induced deacetylation of the microtubule protein α-tubulin and hyperphosphorylation of the microtubule-associated protein tau. These cisplatin-induced changes were reversed by HDAC6 inhibition. Our data suggest that inhibition of HDAC6 restores microtubule stability and reverses tau phosphorylation, leading to normalization of synaptosomal mitochondrial function and synaptic integrity and thereby to reversal of CICI. Remarkably, our results indicate that short-term daily treatment with the HDAC6 inhibitor was sufficient to achieve prolonged reversal of established behavioral, structural and functional deficits induced by cisplatin. Because the beneficial effects of HDAC6 inhibitors as add-ons to cancer treatment have been demonstrated in clinical trials, selective targeting of HDAC6 with brain-penetrating inhibitors appears a promising therapeutic approach for reversing chemotherapy-induced neurotoxicity while enhancing tumor control.

Topics: Animals; Antineoplastic Agents; Cisplatin; Cognitive Dysfunction; Disease Models, Animal; Disks Large Homolog 4 Protein; Dose-Response Relationship, Drug; Enzyme Inhibitors; Green Fluorescent Proteins; Histone Deacetylase 6; Hydroxamic Acids; Male; Maze Learning; Mice; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Mitochondria; Pyrimidines; Recombinant Fusion Proteins; Synaptosomes; tau Proteins; Tauopathies; Time Factors; Tubulin