title: Evaluation of tubulin polymerization and chronic inhibition of proteasome as citotoxicity mechanisms in bortezomib-induced peripheral neuropathy.
abstract: Bortezomib (BTZ) is the first proteasome inhibitor entered in clinical practice. Peripheral neuropathy is likely to be a class side effect of these drugs, although its severity is largely variable, and it deserves to be further investigated, since the mechanisms of BTZ-induced peripheral neurotoxicity (BiPN) are still unknown.   In our study, we investigated in vivo and in vitro possible pathogenic events relevant to BiPN using a well-established rat model, with particular reference to the extent of proteasome inhibition and the effects on α-tubulin polymerization in sciatic nerves and dorsal root ganglia specimens obtained from animals treated with chronic regimens at a dose of 0.2 mg/kg intravenously. The same assessments were also performed after a single injection. Moreover, these studies were replicated in vitro using embryonic DRG neurons exposed to 100 nM BTZ and adult DRG neurons exposed to 10-50 nM BTZ for 24 h and 48 h. A significant increase in the polymerized fraction of α-tubulin and prolonged proteasome inhibition were observed after the chronic BTZ treatment in vivo. Recovery to physiological levels was observed after a 4-week follow-up post-treatment period. Proteasome inhibition and increased α-tubulin polymerization were also observed following BTZ treatment of both embryonic and adult DRG neurons in vitro. Our in vivo results suggest that proteasome inhibition and alteration of tubulin dynamics contribute to BiPN. The in vitro systems here described reliably replicate the in vivo results, and might therefore be used for further mechanistic studies on the effects of proteasome inhibitors on neurons.
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Cristina
authors: C
authors: Meregalli
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Alessia
authors: A
authors: Chiorazzi
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Valentina A
authors: VA
authors: Carozzi
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Annalisa
authors: A
authors: Canta
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Barbara
authors: B
authors: Sala
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Matteo
authors: M
authors: Colombo
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Norberto
authors: N
authors: Oggioni
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Cecilia
authors: C
authors: Ceresa
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Dana
authors: D
authors: Foudah
authors: Wolfson Centre for Age-Related Diseases; King's College London; London, UK.
authors: Federica
authors: F
authors: La Russa
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Mariarosaria
authors: M
authors: Miloso
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Gabriella
authors: G
authors: Nicolini
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Paola
authors: P
authors: Marmiroli
authors: Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford, UK.
authors: David Lh
authors: DL
authors: Bennett
authors: Experimental Neurology Unit; Department of Surgery and Translational Medicine; University of Milan Bicocca; Monza, Italy.
authors: Guido
authors: G
authors: Cavaletti
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity*; D001897:Boronic Acids / Q000633:toxicity*; D000069286:Bortezomib; D002460:Cell Line; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors / Q000633:toxicity*; D011719:Pyrazines / Q000633:toxicity*; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014404:Tubulin / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D001897:Boronic Acids; D061988:Proteasome Inhibitors; D011719:Pyrazines; D014404:Tubulin; D000069286:Bortezomib; D046988:Proteasome Endopeptidase Complex
keywords: Bortezomib; neuronal cultures; peripheral neuropathy; proteasome inhibitor; α-tubulin polymerization