title: The selective poly(ADP-ribose) polymerase-1(2) inhibitor, CEP-8983, increases the sensitivity of chemoresistant tumor cells to temozolomide and irinotecan but does not potentiate myelotoxicity.
abstract: The effect of the potent and selective poly(ADP-ribose) (PAR) polymerase-1 [and PAR polymerase-2] inhibitor CEP-8983 on the ability to sensitize chemoresistant glioblastoma (RG2), rhabdomyosarcoma (RH18), neuroblastoma (NB1691), and colon carcinoma (HT29) tumor cells to temozolomide- and camptothecin-induced cytotoxicity, DNA damage, and G(2)-M arrest and on the potentiation of chemotherapy-induced myelotoxicity was evaluated using in vitro assays. In addition, the effect of the prodrug CEP-9722 in combination with temozolomide and/or irinotecan on PAR accumulation and tumor growth was also determined using glioblastoma and/or colon carcinoma xenografts relative to chemotherapy alone. CEP-8983 sensitized carcinoma cells to the growth-inhibitory effects of temozolomide and/or SN38 increased the fraction of and/or lengthened duration of time tumor cells accumulated in chemotherapy-induced G(2)-M arrest and sensitized tumor cells to chemotherapy-induced DNA damage and apoptosis. A granulocyte-macrophage colony-forming unit colony formation assay showed that coincubation of CEP-8983 with temozolomide or topotecan did not potentiate chemotherapy-associated myelotoxicity. CEP-9722 (136 mg/kg) administered with temozolomide (68 mg/kg for 5 days) or irinotecan (10 mg/kg for 5 days) inhibited significantly the growth of RG2 tumors (60%) or HT29 tumors (80%) compared with temozolomide or irinotecan monotherapy, respectively. In addition, CEP-9722 showed "stand alone" antitumor efficacy in these preclinical xenografts. In vivo biochemical efficacy studies showed that CEP-9722 attenuated PAR accumulation in glioma xenografts in a dose- and time-related manner. These data indicate that CEP-8983 and its prodrug are effective chemosensitizing agents when administered in combination with select chemotherapeutic agents against chemoresistant tumors.
authors: Cephalon, Inc., 145 Brandywine Parkway, West Chester, PA 19380, USA. smiknyoc@cephalon.com
authors: Sheila
authors: S
authors: Miknyoczki
authors: Hong
authors: H
authors: Chang
authors: Jennifer
authors: J
authors: Grobelny
authors: Sonya
authors: S
authors: Pritchard
authors: Candace
authors: C
authors: Worrell
authors: Natalie
authors: N
authors: McGann
authors: Mark
authors: M
authors: Ator
authors: Jean
authors: J
authors: Husten
authors: James
authors: J
authors: Deibold
authors: Robert
authors: R
authors: Hudkins
authors: Allison
authors: A
authors: Zulli
authors: Ralph
authors: R
authors: Parchment
authors: Bruce
authors: B
authors: Ruggeri
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D020552:Comet Assay; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D000077146:Irinotecan; D051379:Mice; D010797:Phthalimides / Q000494:pharmacology*; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D051381:Rats; D000077204:Temozolomide; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C523456:CEP 8983; C000597465:CEP-9722; D002227:Carbazoles; D004791:Enzyme Inhibitors; D010797:Phthalimides; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011064:Poly Adenosine Diphosphate Ribose; D000077146:Irinotecan; D003606:Dacarbazine; D002166:Camptothecin; D000077204:Temozolomide