title: Pharmacological inhibition of polo like kinase 2 (PLK2) does not cause chromosomal damage or result in the formation of micronuclei.
abstract: Polo like kinase 2 (PLK2) phosphorylates α-synuclein and is considered a putative therapeutic target for Parkinson's disease. Several lines of evidence indicate that PLK2 is involved with proper centriole duplication and cell cycle regulation, inhibition of which could impact chromosomal integrity during mitosis. The objectives of the series of experiments presented herein were to assess whether specific inhibition of PLK2 is genotoxic and determine if PLK2 could be considered a tractable pharmacological target for Parkinson's disease. Several selective PLK2 inhibitors, ELN 582175 and ELN 582646, and their inactive enantiomers, ELN 582176 and ELN 582647, did not significantly increase the number of micronuclei in the in vitro micronucleus assay. ELN 582646 was administered to male Sprague Dawley rats in an exploratory 14-day study where flow cytometric analysis of peripheral blood identified a dose-dependent increase in the number of micronucleated reticulocytes. A follow-up investigative study demonstrated that ELN 582646 administered to PLK2 deficient and wildtype mice significantly increased the number of peripheral micronucleated reticulocytes in both genotypes, suggesting that ELN 582646-induced genotoxicity is not through the inhibition of PLK2. Furthermore, significant reduction of retinal phosphorylated α-synuclein levels was observed at three non-genotoxic doses, additional data to suggest that pharmacological inhibition of PLK2 is not the cause of the observed genotoxicity. These data, in aggregate, indicate that PLK2 inhibition is a tractable CNS pharmacological target that does not cause genotoxicity at doses and exposures that engage the target in the sensory retina.
authors: Pharmacological Sciences, Elan Pharmaceuticals Inc., 180 Oyster Point Boulevard, South San Francisco, CA 94080, USA.
authors: Kent
authors: K
authors: Fitzgerald
authors: Marcelle
authors: M
authors: Bergeron
authors: Christopher
authors: C
authors: Willits
authors: Simeon
authors: S
authors: Bowers
authors: Danielle L
authors: DL
authors: Aubele
authors: Erich
authors: E
authors: Goldbach
authors: George
authors: G
authors: Tonn
authors: Daniel
authors: D
authors: Ness
authors: Andrew
authors: A
authors: Olaharski
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations / Q000139:chemically induced*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D057809:HEK293 Cells; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced*; D015162:Micronucleus Tests; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000493:pharmacokinetics / Q000633:toxicity*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012156:Reticulocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D012160:Retina / Q000187:drug effects / Q000378:metabolism; D018570:Risk Assessment; D013997:Time Factors; D014162:Transfection; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism
chemical_list: D047428:Protein Kinase Inhibitors; D051844:alpha-Synuclein; C496126:PLK2 protein, human; D017346:Protein Serine-Threonine Kinases; C530504:Plk2 protein, rat; C444640:serum-inducible kinase