title: Preclinical evidence for nitrogen-containing bisphosphonate inhibition of farnesyl diphosphate (FPP) synthase in the kidney: implications for renal safety.
abstract: Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption and play an important role in the treatment of osteoporosis, metastatic bone disease, and Paget disease. However, nephrotoxicity has been reported with some bisphosphonates. Nitrogen-containing bisphosphonates directly inhibit farnesyl diphosphate (FPP) synthase activity (mevalonate pathway) and reduce protein prenylation leading to osteoclast cell death. The aim here was to elucidate if this inhibition also occurs in kidney cells and may directly account for nephrotoxicity. In an exploratory study in rats receiving zoledronate or ibandronate an approximate 2-fold increase in FPP synthase mRNA levels was observed in the kidney. The involvement of the mevalonate pathway was confirmed in subsequent in vitro studies with zoledronate, ibandronate, and pamidronate, using the non-nitrogen containing bisphosphonate clodronate as a comparator. In vitro changes in FPP synthase mRNA expression, enzyme activity, and levels of prenylated proteins were assessed. Using two cell lines (a rat normal kidney cell line, NRK-52E, and a human kidney proximal tubule cell line, HK-2), ibandronate and zoledronate were identified as most cytotoxic (EC50: 23/>1000 microM and 16/82 microM, respectively) and as the most potent inhibitors of FPP synthase (IC50; 1.6/7.4 microM and 0.5/0.7 microM, respectively). In both cell lines, inhibition of FPP synthase activity occurred prior to a decrease in levels of prenylated proteins followed by cytotoxicity. This further supports that the mechanism responsible for osteoclast inhibition (therapeutic effect) might also underlie the mechanism of nephrotoxicity.
authors.affiliation: F. Hoffmann-La Roche Ltd., Non-Clinical Drug Safety, CH-4070 Basel, Switzerland. anke.luehe@roche.com <anke.luehe@roche.com>
authors.forename: Anke
authors.initials: A
authors.lastname: Lühe
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Künkele
authors.forename: Monika
authors.initials: M
authors.lastname: Haiker
authors.forename: Karen
authors.initials: K
authors.lastname: Schad
authors.forename: Christine
authors.initials: C
authors.lastname: Zihlmann
authors.forename: Frieder
authors.initials: F
authors.lastname: Bauss
authors.forename: Laura
authors.initials: L
authors.lastname: Suter
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfister
mesh_terms: D000818:Animals; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000633:toxicity; D002460:Cell Line; D004002:Clodronic Acid / Q000633:toxicity; D004164:Diphosphonates / Q000008:administration & dosage / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D051228:Geranyltranstransferase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D000077557:Ibandronic Acid; D007093:Imidazoles / Q000008:administration & dosage / Q000633:toxicity*; D020128:Inhibitory Concentration 50; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D000077268:Pamidronate; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077211:Zoledronic Acid
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; D012333:RNA, Messenger; D004002:Clodronic Acid; D000077211:Zoledronic Acid; D051228:Geranyltranstransferase; D000077268:Pamidronate; D000077557:Ibandronic Acid