title: Pin1 dysregulation helps to explain the inverse association between cancer and Alzheimer's disease.
abstract: BACKGROUND
  Pin1 is an intracellular signaling molecule which plays a critical but opposite role in the pathogenesis of Alzheimer's disease (AD) and many human cancers.
  
  
  METHODS
  We review the structure and function of the Pin1 enzyme, the diverse roles it plays in cycling cells and neurons, the epidemiologic evidence for the inverse association between cancer and AD, and the potential therapeutic implications of Pin1-based therapies.
  
  
  CONCLUSIONS
  Pin1 is a unique enzyme that has effects on the function of target proteins by "twisting" them into different shapes. Cycling cells use Pin1 to help coordinate cell division. It is over-expressed and/or activated by multiple mechanisms in many common human cancers, and acts on multiple signal pathways to promote tumorigenesis. Inhibition of Pin1 in animal models has profound anti-tumor effects. In contrast, Pin1 is down-regulated or inactivated by multiple mechanisms in AD brains. The absence of Pin1 impairs tau function and amyloid precursor protein processing, leading to tangle- and amyloid-related pathologies and neurodegeneration in an age-dependent manner, resembling human AD. We have developed cis and trans conformation-specific antibodies to provide the first direct evidence that tau exists in distinct cis and trans conformations and that Pin1 accelerates its cis to trans conversion, thereby protecting against tangle formation in AD.
  
  
  CONCLUSIONS
  Available studies on Pin1 suggest that cancer and AD may share biological pathways that are deregulated in different directions. Pin1 biology opens exciting preventive and therapeutic horizons for both cancer and neurodegeneration. This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets.
authors.affiliation: Geriatric Research Education and Clinical Center, VA Boston Healthcare System and the Division of Aging, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: jdriver@partners.org.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Driver
authors.affiliation: Cancer Research Institute, Beth Israel Deaconess Cancer Center and Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. Electronic address: xzhou@bidmc.harvard.edu.
authors.forename: Xiao Zhen
authors.initials: XZ
authors.lastname: Zhou
authors.affiliation: Cancer Research Institute, Beth Israel Deaconess Cancer Center and Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. Electronic address: klu@bidmc.harvard.edu.
authors.forename: Kun Ping
authors.initials: KP
authors.lastname: Lu
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D000682:Amyloid / Q000235:genetics / Q000378:metabolism; D000818:Animals; D006801:Humans; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000682:Amyloid; C054369:MAPT protein, human; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D009363:Neoplasm Proteins; D016875:tau Proteins; C000606846:PIN1 protein, human; D019696:Peptidylprolyl Isomerase
keywords: Alzheimer's disease; Cancer; Phosphorylation signaling; Pin1