title: Oral administration of the immunomodulator JBT-3002 induces endogenous interleukin 15 in intestinal macrophages for protection against irinotecan-mediated destruction of intestinal epithelium.
abstract: We recently reported that p.o. administration of the new synthetic bacterial lipopeptide JBT-3002 can protect mice from irinotecan (CPT-11)-induced intestinal injury, but the mechanism was not known. Because interleukin-15 (IL-15) is associated with maintenance of intestinal epithelial cell integrity, we examined whether p.o. administration of JBT-3002 elevates expression of this monocyte-derived cytokine. Four daily i.p. injections of 100 mg/kg CPT-11 were effective against liver metastases produced by CT-26 murine colon cancer cells, but severe damage to the intestinal epithelium and early death of the mice also resulted. Three consecutive daily p.o. doses of JBT-3002 prior to i.p. injection of irinotecan prevented the undesirable side effects of irinotecan without reducing its ability to eradicate liver metastases. Immunohistochemical analyses of the intestines of mice treated with JBT-3002 and CPT-11 demonstrated an increase in the number of dividing cells in the crypts and enhanced expression of IL-15 in lamina propria cells; the increase correlated with increased expression of the IL-15 gene as determined by semiquantitative reverse transcriptase-PCR. In vitro studies demonstrated that JBT-3002 induced expression of IL-15 in peritoneal macrophages but not in normal intestinal epithelial cells (IEC-6). Moreover, the presence of IL-15 decreased irinotecan-mediated cytotoxicity of IEC-6 epithelial cells. These data show that the p.o. administration of JBT-3002 induces expression of IL-15 by macrophages in the lamina propria, which can prevent irinotecan-induced injury to the intestinal mucosa.
authors.affiliation: Department of Cancer Biology, The University of Texas, M.D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: H
authors.initials: H
authors.lastname: Shinohara
authors.forename: J J
authors.initials: JJ
authors.lastname: Killion
authors.forename: C D
authors.initials: CD
authors.lastname: Bucana
authors.forename: S
authors.initials: S
authors.lastname: Yano
authors.forename: I J
authors.initials: IJ
authors.lastname: Fidler
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000633:toxicity*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects; D007082:Ileum / Q000187:drug effects / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D007150:Immunohistochemistry; D019409:Interleukin-15 / Q000096:biosynthesis*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D000077146:Irinotecan; D055666:Lipopeptides; D008074:Lipoproteins / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008855:Microscopy, Electron, Scanning; D009368:Neoplasm Transplantation; D051381:Rats; D013047:Specific Pathogen-Free Organisms
chemical_list: D000276:Adjuvants, Immunologic; D000972:Antineoplastic Agents, Phytogenic; D019409:Interleukin-15; C112524:JBT-3002; D055666:Lipopeptides; D008074:Lipoproteins; D000077146:Irinotecan; D002166:Camptothecin