title: Synergistic antiproliferative and apoptotic effects induced by mixed epidermal growth factor receptor inhibitor ZD1839 and nitric oxide donor in human prostatic cancer cell lines.
abstract: BACKGROUND
  The specific inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, ZD1839 induces potent antitumoral effects on several advanced cancer types. The present study was undertaken to determine whether the combination of ZD1839 with an agent donating nitric oxide (NO(*)), sodium nitroprusside (SNP) results in a synergy of anticarcinogenic responses on metastatic prostate cancer (PC) cells.
  
  
  METHODS
  The antiproliferative and apoptotic/necrotic effects of ZD1839 and SNP alone or in combination were estimated on EGF- and serum-stimulated LNCaP, DU145, and PC3 cells by MTT growth tests, trypan blue dye exclusion method, and flow cytometric analyses. Moreover, the cellular ceramide levels were evaluated by the diacylglycerol kinase enzymatic method and the amounts of cytosolic cytochrome c by ELISA assays.
  
  
  RESULTS
  ZD1839 and SNP alone or in combination at lower concentrations induced an inhibition of EGF- and serum-stimulated growth of LNCaP, DU145, and PC3 concomitant with an arrest in the G1 phase of cellular cycle. Interestingly, the mixed ZD1839 and SNP also caused a more substantial apoptotic/necrotic death of these PC cells as compared to drugs alone. Moreover, we have observed that an inhibition of acidic sphingomyelinase, hydrogen peroxide (H(2)O(2)) accumulation and caspase cascades results in a significant reduction of apoptotic/necrotic death induced by mixed ZD1839 and SNP in EGF-stimulated PC3 cells. In addition, the combined ZD1839 plus SNP also induced a higher cellular ceramide and reactive oxygen species (ROS) production, mitochondrial transmembrane potential decrease, and cytochrome c amount released into cytosol as compared to drugs alone.
  
  
  CONCLUSIONS
  The simultaneous use of EGFR inhibitor and compound releasing NO(*) might lead to a synergy in the ceramide and ROS production which might cause cellular membrane damages resulting in a massive apoptotic/necrotic death of metastatic PC cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors.forename: Murielle
authors.initials: M
authors.lastname: Mimeault
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jouy
authors.forename: Patrick
authors.initials: P
authors.lastname: Depreux
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Hénichart
mesh_terms: D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002518:Ceramides / Q000378:metabolism; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D000077156:Gefitinib; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D020030:Nitric Oxide Donors / Q000633:toxicity*; D009599:Nitroprusside / Q000633:toxicity*; D011471:Prostatic Neoplasms; D011799:Quinazolines / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002518:Ceramides; D020030:Nitric Oxide Donors; D011799:Quinazolines; D017382:Reactive Oxygen Species; D009599:Nitroprusside; D066246:ErbB Receptors; D020169:Caspases; D000077156:Gefitinib