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: Graziella Pratesi, Giovanna Petrangolini, Monica Tortoreto, Alessandro Addis, Sara Belluco, Anna Rossini, Silvia Selleri, Cristiano Rumio, Sylvie Menard, Andrea Balsari
• Journal: Cancer research (Cancer Res) Vol. 65 Issue 14 Pg. 6388-93 (Jul 15 2005) ISSN: 0008-5472 [Print] United States
• PMID: 16024642 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA-Binding Proteins
• Oligonucleotides
• Receptors, Cell Surface
• TLR9 protein, human
• Tlr9 protein, mouse
• Toll-Like Receptor 9
• Deoxycytidine
• Gemcitabine

Topics

• Animals
• Antineoplastic Combined Chemotherapy Protocols (pharmacology)
• Combined Modality Therapy
• CpG Islands (genetics)
• DNA-Binding Proteins (biosynthesis, deficiency, genetics)
• Deoxycytidine (administration & dosage, analogs & derivatives)
• Drug Synergism
• Female
• Humans
• Immunotherapy
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Mice, Nude
• Oligonucleotides (administration & dosage, genetics)
• Pancreatic Neoplasms (drug therapy, genetics, metabolism)
• Receptors, Cell Surface (biosynthesis, deficiency, genetics)
• Toll-Like Receptor 9
• Tumor Cells, Cultured
• Xenograft Model Antitumor Assays
• Gemcitabine