title: Identification of oxidized protein hydrolase as a potential prodrug target in prostate cancer.
abstract: BACKGROUND
  Esterases are often overexpressed in cancer cells and can have chiral specificities different from that of the corresponding normal tissues. For this reason, ester prodrugs could be a promising approach in chemotherapy. In this study, we focused on the identification and characterization of differentially expressed esterases between non-tumorigenic and tumorigenic prostate epithelial cells.
  
  
  METHODS
  Cellular lysates from LNCaP, DU 145, and PC3 prostate cancer cell lines, tumorigenic RWPE-2 prostate epithelial cells, and non-tumorigenic RWPE-1 prostate epithelial cells were separated by native polyacrylamide gel electrophoresis (n-PAGE) and the esterase activity bands visualized using α-naphthyl acetate or α-naphthyl-N-acetylalaninate (ANAA) chiral esters and Fast Blue RR salt. The esterases were identified using nanospray LC/MS-MS tandem mass spectrometry and confirmed by Western blotting, native electroblotting, inhibition assays, and activity towards a known specific substrate. The serine protease/esterase oxidized protein hydrolase (OPH) was overexpressed in COS-7 cells to verify our results.
  
  
  RESULTS
  The major esterase observed with the ANAA substrates within the n-PAGE activity bands was identified as OPH. OPH (EC 3.4.19.1) is a serine protease/esterase and a member of the prolyl oligopeptidase family. We found that LNCaP lysates contained approximately 40% more OPH compared to RWPE-1 lysates. RWPE-2, DU145 and PC3 cell lysates had similar levels of OPH activity. OPH within all of the cell lysates tested had a chiral preference for the S-isomer of ANAA. LNCaP cells were stained more intensely with ANAA substrates than RWPE-1 cells and COS-7 cells overexpressing OPH were found to have a higher activity towards the ANAA and AcApNA than parent COS-7 cells.
  
  
  CONCLUSIONS
  These data suggest that prodrug derivatives of ANAA and AcApNA could have potential as chemotherapeutic agents for the treatment of prostate cancer tumors that overexpress OPH.
authors: Christopher A
authors: CA
authors: McGoldrick
authors: Yu-Lin
authors: YL
authors: Jiang
authors: Victor
authors: V
authors: Paromov
authors: Marianne
authors: M
authors: Brannon
authors: Koyamangalath
authors: K
authors: Krishnan
authors: Department of Pediatrics, East Tennessee State University, P,O, Box 70579, Johnson City, TN 37614, USA. stone@etsu.edu.
authors: William L
authors: WL
authors: Stone
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D004950:Esterases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006801:Humans; D006867:Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction / Q000187:drug effects; D011355:Prodrugs / Q000008:administration & dosage*; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000201:enzymology*; D051381:Rats; D013552:Swine
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D011355:Prodrugs; D006867:Hydrolases; D004950:Esterases