title: Therapeutic synergism of gemcitabine and CpG-oligodeoxynucleotides in an orthotopic human pancreatic carcinoma xenograft.
abstract: CpG-oligodeoxynucleotides (CpG-ODN) exhibit potent immunostimulatory activity by binding with Toll-like receptor 9 (TLR9). Based on the finding that TLR9 is highly expressed and functional in pancreatic tissue, we evaluated the antitumor effects of chemotherapy combined with CpG-ODNs in the orthotopic mouse model of a human pancreatic tumor xenograft. Chemotherapy consisted of the maximum tolerated dose of gemcitabine (i.v., 100 mg/kg, q3dx4). CpG-ODNs were delivered (i.p., 20 microg/mouse), weekly, after the end of chemotherapy. CpG-ODNs alone had little effect on tumor growth, whereas gemcitabine alone significantly delayed the median time of disease onset (palpable i.p. tumor) and of bulky disease development (extensive peritoneal tumor burden), but did not enhance survival time. When the gemcitabine regimen was followed by administration of the immunostimulator, development of bulky disease was delayed, survival time was significantly improved (median survival time, 106 days; P < 0.02 versus gemcitabine-treated mice). Autoptic examination showed that tumor spread in the peritoneal cavity was reduced to a greater extent than with gemcitabine alone. All treatment regimens were well-tolerated. The use of nude mice excluded a T cell-mediated immune response, whereas the high pancreatic expression of TLR9 might have contributed to the tumor response. The clear improvement of survival observed in an orthotopic murine model of human pancreatic cancer by the combined use of CpG-ODNs with chemotherapy suggests the promise of this therapeutic regimen in the clinical setting.
authors: Preclinical Chemotherapy and Pharmacology Unit, Istituto Nazionale Tumori, Milan, Italy. graziella.pratesi@istitutotumori.mi.it
authors: Graziella
authors: G
authors: Pratesi
authors: Giovanna
authors: G
authors: Petrangolini
authors: Monica
authors: M
authors: Tortoreto
authors: Alessandro
authors: A
authors: Addis
authors: Sara
authors: S
authors: Belluco
authors: Anna
authors: A
authors: Rossini
authors: Silvia
authors: S
authors: Selleri
authors: Cristiano
authors: C
authors: Rumio
authors: Sylvie
authors: S
authors: Menard
authors: Andrea
authors: A
authors: Balsari
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D003131:Combined Modality Therapy; D018899:CpG Islands / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D004357:Drug Synergism; D005260:Female; D006801:Humans; D007167:Immunotherapy; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D009841:Oligonucleotides / Q000008:administration & dosage / Q000235:genetics; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D051217:Toll-Like Receptor 9; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine
chemical_list: D004268:DNA-Binding Proteins; D009841:Oligonucleotides; D011956:Receptors, Cell Surface; C495371:TLR9 protein, human; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D003841:Deoxycytidine; D000093542:Gemcitabine