title: APE1, the DNA base excision repair protein, regulates the removal of platinum adducts in sensory neuronal cultures by NER.
abstract: Peripheral neuropathy is one of the major side effects of treatment with the anticancer drug, cisplatin. One proposed mechanism for this neurotoxicity is the formation of platinum adducts in sensory neurons that could contribute to DNA damage. Although this damage is largely repaired by nuclear excision repair (NER), our previous findings suggest that augmenting the base excision repair pathway (BER) by overexpressing the repair protein APE1 protects sensory neurons from cisplatin-induced neurotoxicity. The question remains whether APE1 contributes to the ability of the NER pathway to repair platinum-damage in neuronal cells. To examine this, we manipulated APE1 expression in sensory neuronal cultures and measured Pt-removal after exposure to cisplatin. When neuronal cultures were treated with increasing concentrations of cisplatin for two or three hours, there was a concentration-dependent increase in Pt-damage that peaked at four hours and returned to near baseline levels after 24h. In cultures where APE1 expression was reduced by ∼ 80% using siRNA directed at APE1, there was a significant inhibition of Pt-removal over eight hours which was reversed by overexpressing APE1 using a lentiviral construct for human wtAPE1. Overexpressing a mutant APE1 (C65 APE1), which only has DNA repair activity, but not its other significant redox-signaling function, mimicked the effects of wtAPE1. Overexpressing DNA repair activity mutant APE1 (226 + 177APE1), with only redox activity was ineffective suggesting it is the DNA repair function of APE1 and not its redox-signaling, that restores the Pt-damage removal. Together, these data provide the first evidence that a critical BER enzyme, APE1, helps regulate the NER pathway in the repair of cisplatin damage in sensory neurons.
authors.affiliation: Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202, USA.
authors.forename: Hyun-Suk
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Pharmacology and Toxicology, Indianapolis, IN 46202, USA.
authors.forename: Chunlu
authors.initials: C
authors.lastname: Guo
authors.affiliation: Department of Pharmacology and Toxicology, Indianapolis, IN 46202, USA.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Thompson
authors.affiliation: Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202, USA; Department of Pharmacology and Toxicology, Indianapolis, IN 46202, USA; Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Kelley
authors.affiliation: Department of Pharmacology and Toxicology, Indianapolis, IN 46202, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Vasko
authors.affiliation: Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202, USA. Electronic address: slee@iu.edu.
authors.forename: Suk-Hee
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000818:Animals; D002945:Cisplatin / Q000009:adverse effects; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D061251:Primary Cell Culture; D051381:Rats; D011984:Sensory Receptor Cells / Q000187:drug effects* / Q000378:metabolism
chemical_list: C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D002945:Cisplatin
keywords: APE1; Base excision repair; Cisplatin damage; Nucleotide excision repair; Replication protein A; Sensory neuronal cultures