title: A pilot evaluation of the use of tissue microarrays for quantitation of target distribution in drug discovery pathology.
abstract: The use of tissue microarrays (TMAs) in the determination of novel target molecule distribution in organs is an expanding area of discovery pathology. This pilot study was carried out to assess the Chromavision automated cellular imaging system (ACIS) for quantitation of both mRNA and protein distribution in rat and dog TMAs. The targets chosen were a protein kinase, P-CIP2, for mRNA assessment and its downsteam target, peptidylglycine amidating monoxygenase (PAM), for immunohistochemistry (IHC). Oligonucleotide probes produced against P-CIP2, together with an antibody against PAM, were evaluated on rat and dog TMAs. A method for evaluation of target distribution using the ACIS was developed and involved a two-tier approach. Firstly, an initial scanning of the labelled slides identified which tissues expressed the target. Secondly, a more comprehensive analysis was made. This required operator interaction to select specific regions of interest within selected tissue cores and exclude any background labelling from the final assessment. This exacted the level of expression of P-CIP2 or PAM in different cellular populations in tissue cores. A comparative semi-quantitative analysis of the same arrays was concomitantly made by the pathologist in order to assess the relative benefits of a potentially time-consuming detailed morphological evaluation. This involved the histological identification by the pathologist of specific cell populations expressing P-CIP2 or PAM. In this study, we demonstrate the power of an image analysing system to provide quantitative data on target distribution by in situ hybridisation and IHC on normal TMAs. This methodology, together with detailed histological analysis by a pathologist, forms a guideline for future target distribution evaluation within discovery pathology.
authors.affiliation: Department of Pathology, Safety Assessment, AstraZeneca, Alderley Park, Cheshire SK10 4TG, UK. jenny.mckay@astrazeneca.com
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: McKay
authors.forename: Alison
authors.initials: A
authors.lastname: Bigley
authors.forename: Alex
authors.initials: A
authors.lastname: Bell
authors.forename: Richard
authors.initials: R
authors.lastname: Jenkins
authors.forename: Rebecca
authors.initials: R
authors.lastname: Somers
authors.forename: Simon
authors.initials: S
authors.lastname: Brocklehurst
authors.forename: Anne
authors.initials: A
authors.lastname: White
authors.forename: Louise
authors.initials: L
authors.lastname: Goodwin
mesh_terms: D000818:Animals; D001331:Automation; D002352:Carrier Proteins / Q000032:analysis / Q000096:biosynthesis*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis / Q000096:biosynthesis*; D004285:Dogs; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D006899:Mixed Function Oxygenases / Q000032:analysis / Q000096:biosynthesis*; D009097:Multienzyme Complexes / Q000032:analysis / Q000096:biosynthesis*; D010599:Pharmacokinetics; D040081:Protein Array Analysis; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D013048:Specimen Handling
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; C102364:Uhmk1 protein, rat; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases