title: Inhibition of poly(ADP-ribose) polymerase prevents irinotecan-induced intestinal damage and enhances irinotecan/temozolomide efficacy against colon carcinoma.
abstract: Poly(ADP-ribose) polymerase (PARP) inhibitors enhance the antitumor activity of the topoisomerase I inhibitor irinotecan (CPT-11), which is used to treat advanced colorectal carcinoma. Since PARP inhibitors sensitize tumor cells also to the methylating agent temozolomide (TMZ) and clinical trials are evaluating CPT-11 in combination with TMZ, we tested whether the PARP inhibitor GPI 15427 (10-(4-methyl-piperazin-1-ylmethyl)-2H-7-oxa-1,2-diaza-benzo[de]anthracen-3-one) increases the efficacy of CPT-11 + TMZ against colon cancer. Moreover, due to the ability of PARP inhibitors to avoid cell death consequent to PARP-1 overactivation, we evaluated whether oral administration of GPI 15427 provides protection from the dose-limiting intestinal toxicity of CPT-11. The results of colony formation assay indicated that GPI 15427 increased the antiproliferative effects (combination index <1) of TMZ + SN-38 (the active metabolite of CPT-11) against colon cancer cells. Accordingly, GPI 15427 (40 mg/kg/dayx5 days per os) in combination with TMZ (10 mg/kg/dayx5 days) + CPT-11 (4 mg/kg/dayx5 days) significantly reduced the growth of tumor xenografts. Oral administration of GPI 15427 (40 mg/kg/q2x3 days) prevented intestinal injury and diarrhea induced by CPT-11 (30 mg/kg/day x 3 days) reducing inflammation and PARP-1 overactivation, as evidenced by immunohistochemical staining of intestinal tissue with antipoly(ADP-ribose) antibody (Ab). In conclusion, the PARP inhibitor represents a novel strategy to enhance the antitumor efficacy and reduce toxicity of chemotherapy in colon cancer.
authors.affiliation: Department of Neuroscience, University of Rome Tor Vergata, Via Montpellier 1, Rome 00133, Italy.
authors.forename: Lucio
authors.initials: L
authors.lastname: Tentori
authors.forename: Carlo
authors.initials: C
authors.lastname: Leonetti
authors.forename: Marco
authors.initials: M
authors.lastname: Scarsella
authors.forename: Alessia
authors.initials: A
authors.lastname: Muzi
authors.forename: Emanuela
authors.initials: E
authors.lastname: Mazzon
authors.forename: Matteo
authors.initials: M
authors.lastname: Vergati
authors.forename: Olindo
authors.initials: O
authors.lastname: Forini
authors.forename: Rena
authors.initials: R
authors.lastname: Lapidus
authors.forename: Weizheng
authors.initials: W
authors.lastname: Xu
authors.forename: Annalisa Susanna
authors.initials: AS
authors.lastname: Dorio
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cuzzocrea
authors.forename: Grazia
authors.initials: G
authors.lastname: Graziani
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use; D002166:Camptothecin / Q000009:adverse effects / Q000031:analogs & derivatives*; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy*; D003114:Colony-Forming Units Assay; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D003967:Diarrhea / Q000517:prevention & control; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D007410:Intestinal Diseases / Q000139:chemically induced / Q000473:pathology*; D000077146:Irinotecan; D009930:Organic Chemicals / Q000494:pharmacology / Q000627:therapeutic use; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D000077204:Temozolomide; D059004:Topoisomerase I Inhibitors; D047368:Tumor Burden / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D009930:Organic Chemicals; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D059004:Topoisomerase I Inhibitors; C502278:GPI 15427; D000077146:Irinotecan; D003606:Dacarbazine; D002166:Camptothecin; D000077204:Temozolomide