title: Reversal of pancreatitis-induced pain by an orally available, small molecule interleukin-6 receptor antagonist.
abstract: Pancreatic pain resulting from chronic inflammation of the pancreas is often intractable and clinically difficult to manage with available analgesics reflecting the need for more effective therapies. The mechanisms underlying pancreatitis pain are not well understood. Here, the possibility that interleukin-6 (IL-6) may promote pancreatitis pain was investigated with TB-2-081 (3-O-formyl-20R,21-epoxyresibufogenin, EBRF), a small molecule IL-6 receptor antagonist that was semi-synthetically derived from natural sources. The potential activity and mechanism of TB-2-081 were investigated following the induction of persistent pancreatitis using dibutyltin dichloride (DBTC) in rats. TB-2-081 displaces the binding of IL-6 to the human recombinant soluble IL-6 receptor with apparent high affinity and inhibits IL-6 mediated cell growth. Systemic or oral, but not intrathecal, administration of TB-2-081 reversed DBTC-induced abdominal hypersensitivity in a dose- and time-dependent manner. IL-6 levels were significantly up-regulated in the dorsal root ganglia (DRG) of rats with pancreatitis on day 6 after DBTC injection. IL-6-enhanced capsaicin-evoked release of calcitonin gene-related peptide from cultured DRG neurons was blocked by TB-2-081. Our data demonstrate that TB-2-081 acts as a systemically available and orally active small molecule IL-6 receptor antagonist. TB-2-081 effectively reduces pancreatitis-induced pain through peripheral mechanisms that are likely due to (a) increased expression of IL-6 in the DRG and (b) IL-6-mediated sensitization of nociceptive neurons. The activity of TB-2-081 implicates an important role for IL-6 in sustaining pancreatitis pain. Strategies targeting IL-6 actions through small molecule antagonists may offer novel approaches to improve the therapy of chronic pancreatitis and other chronic pain states.
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA Scripps Research Institute, La Jolla, CA 92037, USA Drug Design and Synthesis Section, Chemical Biology Research Branch, National Institute On Drug Abuse, the National Institute On Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA Laboratory for the Structure of Matter, Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: Marina
authors.initials: M
authors.lastname: Vardanyan
authors.forename: Ohannes K
authors.initials: OK
authors.lastname: Melemedjian
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Price
authors.forename: Michael H
authors.initials: MH
authors.lastname: Ossipov
authors.forename: Josephine
authors.initials: J
authors.lastname: Lai
authors.forename: Ed
authors.initials: E
authors.lastname: Roberts
authors.forename: Terrence L
authors.initials: TL
authors.lastname: Boos
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Deschamps
authors.forename: Arthur E
authors.initials: AE
authors.lastname: Jacobson
authors.forename: Kenner C
authors.initials: KC
authors.lastname: Rice
authors.forename: Frank
authors.initials: F
authors.lastname: Porreca
mesh_terms: D015746:Abdominal Pain / Q000188:drug therapy* / Q000209:etiology*; D000284:Administration, Oral; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002018:Bufanolides / Q000008:administration & dosage*; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002461:Cell Line, Transformed; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005727:Ganglia, Spinal / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology; D015850:Interleukin-6 / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D009947:Organotin Compounds; D010195:Pancreatitis / Q000139:chemically induced / Q000150:complications*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019947:Receptors, Interleukin-6 / Q000037:antagonists & inhibitors*; D013997:Time Factors; D046509:Tissue Culture Techniques
chemical_list: C466795:20,21-epoxyresibufogenin-3-formate; D002018:Bufanolides; D015850:Interleukin-6; D009947:Organotin Compounds; D019947:Receptors, Interleukin-6; C020735:dibutyldichlorotin; D015740:Calcitonin Gene-Related Peptide