Print Email Facebook Twitter Differentiating the mechanisms of antiresorptive action of nitrogen containing bisphosphonates Title Differentiating the mechanisms of antiresorptive action of nitrogen containing bisphosphonates Author van Beek, E.R. Cohen, L.H. Leroy, I.M. Ebetino, F.H. Löwik, C.W.G.M. Papapoulos, S.E. Gaubius Instituut TNO Publication year 2003 Abstract Bisphosphonates (BPS) inhibit bone resorption and are divided into two classes according to their chemical structure and mechanism of action: nonnitrogen containing BPS such as etidronate and clodronate that are of low potency and inhibit osteoclast function via metabolism into toxic ATP-metabolites and nitrogen-containing BPS (NBPS), such as alendronate and risedronate that inhibit the enzyme of the mevalonate biosynthetic pathway farnesyl pyrophosphate synthase (FPPS), resulting in inhibition of the prenylation of small GTP-binding proteins in osteoclasts and disruption of their cytoskeleton. Previously, studies in various cell types suggested, however, that pamidronate functions by mechanism(s) additional or independent of the mevalonate pathway. To examine if such mechanism(s) are also involved in the action of NBPS on osteoclastic bone resorption, we examined the action of alkyl and heterocyclic NBPS with close structural homology on FPPS/isopentenyl pyrophosphate isomerase (IPPI) activity, on osteoclastic resorption, and on reversibility of this effect with GGOH. As expected, both pamidronate and alendronate suppressed bone resorption and FPPS/IPPI activity, the latter with greater potency than the first. Surprisingly, however, unlike alendronate, the antiresorptive effect of pamidronate was only partially reversible with GGOH, indicating the involvement of mechanism(s) of action additional to that of suppression of FPPS. Comparable results were obtained with the heterocyclic NBP NE-21650, a structural analog of risedronate. Thus, despite an effect on FPPS, the actions on bone resorption of some NBPS may involve mechanisms additional to suppression of FPPS. These findings may lead to identification of additional pathways that are important for bone resorption and may help to differentiate among members of the NBP class which are currently distinguished only according to their potency to inhibit bone resorption. © 2003 Elsevier Inc. All rights reserved. Subject Biomedical ResearchBisphosphonatesBone resorptionFPP synthaseGeranylgeranylationOsteoclastsalendronic acidbisphosphonic acid derivativeetidronic acidgeranylgeraniolgeranyltransferaseisopentenyl diphosphate delta isomerasene 10575ne 11808ne 21650ne 58086nitrogenpamidronic acidrisedronic acidunclassified druganimal experimentanimal tissuearticlecontrolled studydrug activitydrug effectdrug mechanismdrug potencyenzyme activityenzyme repressionfemalefetusnonhumanosteoclastosteolysisstructural homologyAnimalsBone ResorptionCalciumDiphosphonatesDose-Response Relationship, DrugFemaleMetatarsal BonesMiceNitrogenOrgan Culture TechniquesPregnancy To reference this document use: http://resolver.tudelft.nl/uuid:f60261ba-679d-4e14-8495-3e105955a577 DOI https://doi.org/10.1016/j.bone.2003.07.007 TNO identifier 237351 ISSN 8756-3282 Source Bone, 33 (5), 805-811 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.