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Sedghizadeh PP, Sun S, Junka AF, Richard E, Sadrerafi K, Mahabady S, Bakhshalian N, Tjokro N, Bartoszewicz M, Oleksy M, Szymczyk P, Lundy MW, Neighbors JD, Russell RGG, McKenna CE, Ebetino FH. Design, Synthesis, and Antimicrobial Evaluation of a Novel Bone-Targeting Bisphosphonate-Ciprofloxacin Conjugate for the Treatment of Osteomyelitis Biofilms. J Med Chem 2017; 60:2326-2343. [PMID: 28121436 DOI: 10.1021/acs.jmedchem.6b01615] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Osteomyelitis is a major problem worldwide and is devastating due to the potential for limb-threatening sequelae and mortality. Osteomyelitis pathogens are bone-attached biofilms, making antibiotic delivery challenging. Here we describe a novel osteoadsorptive bisphosphonate-ciprofloxacin conjugate (BV600022), utilizing a "target and release" chemical strategy, which demonstrated a significantly enhanced therapeutic index versus ciprofloxacin for the treatment of osteomyelitis in vivo. In vitro antimicrobial susceptibility testing of the conjugate against common osteomyelitis pathogens revealed an effective bactericidal profile and sustained release of the parent antibiotic over time. Efficacy and safety were demonstrated in an animal model of periprosthetic osteomyelitis, where a single dose of 10 mg/kg (15.6 μmol/kg) conjugate reduced the bacterial load by 99% and demonstrated nearly an order of magnitude greater activity than the parent antibiotic ciprofloxacin (30 mg/kg, 90.6 μmol/kg) given in multiple doses. Conjugates incorporating a bisphosphonate and an antibiotic for bone-targeted delivery to treat osteomyelitis biofilm pathogens constitute a promising approach to providing high bone-antimicrobial potency while minimizing systemic exposure.
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Sun S, Błażewska KM, Kadina AP, Kashemirov BA, Duan X, Triffitt JT, Dunford JE, Russell RGG, Ebetino FH, Roelofs AJ, Coxon FP, Lundy MW, McKenna CE. Fluorescent Bisphosphonate and Carboxyphosphonate Probes: A Versatile Imaging Toolkit for Applications in Bone Biology and Biomedicine. Bioconjug Chem 2015; 27:329-40. [PMID: 26646666 DOI: 10.1021/acs.bioconjchem.5b00369] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A bone imaging toolkit of 21 fluorescent probes with variable spectroscopic properties, bone mineral binding affinities, and antiprenylation activities has been created, including a novel linking strategy. The linking chemistry allows attachment of a diverse selection of dyes fluorescent in the visible to near-infrared range to any of the three clinically important heterocyclic bisphosphonate bone drugs (risedronate, zoledronate, and minodronate or their analogues). The resultant suite of conjugates offers multiple options to "mix and match" parent drug structure, fluorescence emission wavelength, relative bone affinity, and presence or absence of antiprenylation activity, for bone-related imaging applications.
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Tsoumpra MK, Muniz JR, Barnett BL, Kwaasi AA, Pilka ES, Kavanagh KL, Evdokimov A, Walter RL, Von Delft F, Ebetino FH, Oppermann U, Russell RGG, Dunford JE. The inhibition of human farnesyl pyrophosphate synthase by nitrogen-containing bisphosphonates. Elucidating the role of active site threonine 201 and tyrosine 204 residues using enzyme mutants. Bone 2015; 81:478-486. [PMID: 26318908 PMCID: PMC4652608 DOI: 10.1016/j.bone.2015.08.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/19/2015] [Accepted: 08/23/2015] [Indexed: 11/22/2022]
Abstract
Farnesyl pyrophosphate synthase (FPPS) is the major molecular target of nitrogen-containing bisphosphonates (N-BPs), used clinically as bone resorption inhibitors. We investigated the role of threonine 201 (Thr201) and tyrosine 204 (Tyr204) residues in substrate binding, catalysis and inhibition by N-BPs, employing kinetic and crystallographic studies of mutated FPPS proteins. Mutants of Thr201 illustrated the importance of the methyl group in aiding the formation of the Isopentenyl pyrophosphate (IPP) binding site, while Tyr204 mutations revealed the unknown role of this residue in both catalysis and IPP binding. The interaction between Thr201 and the side chain nitrogen of N-BP was shown to be important for tight binding inhibition by zoledronate (ZOL) and risedronate (RIS), although RIS was also still capable of interacting with the main-chain carbonyl of Lys200. The interaction of RIS with the phenyl ring of Tyr204 proved essential for the maintenance of the isomerized enzyme-inhibitor complex. Studies with conformationally restricted analogues of RIS reaffirmed the importance of Thr201 in the formation of hydrogen bonds with N-BPs. In conclusion we have identified new features of FPPS inhibition by N-BPs and revealed unknown roles of the active site residues in catalysis and substrate binding.
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Watkins MP, Norris JY, Grimston SK, Zhang X, Phipps RJ, Ebetino FH, Civitelli R. Bisphosphonates improve trabecular bone mass and normalize cortical thickness in ovariectomized, osteoblast connexin43 deficient mice. Bone 2012; 51:787-94. [PMID: 22750450 PMCID: PMC3432742 DOI: 10.1016/j.bone.2012.06.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/15/2012] [Accepted: 06/19/2012] [Indexed: 02/05/2023]
Abstract
The gap junction protein, connexin43 (Cx43) controls both bone formation and osteoclastogenesis via osteoblasts and/or osteocytes. Cx43 has also been proposed to mediate an anti-apoptotic effect of bisphosphonates, potent inhibitors of bone resorption. We studied whether bisphosphonates are effective in protecting mice with a conditional Cx43 gene deletion in osteoblasts and osteocytes (cKO) from the consequences of ovariectomy on bone mass and strength. Ovariectomy resulted in rapid loss of trabecular bone followed by a slight recovery in wild type (WT) mice, and a similar degree of trabecular bone loss, albeit slightly delayed, occurred in cKO mice. Treatment with either risedronate (20 μg/kg) or alendronate (40 μg/kg) prevented ovariectomy-induced bone loss in both genotypes. In basal conditions, bones of cKO mice have larger marrow area, higher endocortical osteoclast number, and lower cortical thickness and strength relative to WT. Ovariectomy increased endocortical osteoclast number in WT but not in cKO mice. Both bisphosphonates prevented these increases in WT mice, and normalized endocortical osteoclast number, cortical thickness and bone strength in cKO mice. Thus, lack of osteoblast/osteocyte Cx43 does not alter bisphosphonate action on bone mass and strength in estrogen deficiency. These results support the notion that one of the main functions of Cx43 in cortical bone is to restrain osteoblast and/or osteocytes from inducing osteoclastogenesis at the endocortical surface.
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Hofstetter B, Gamsjaeger S, Phipps RJ, Recker RR, Ebetino FH, Klaushofer K, Paschalis EP. Effects of alendronate and risedronate on bone material properties in actively forming trabecular bone surfaces. J Bone Miner Res 2012; 27:995-1003. [PMID: 22336962 DOI: 10.1002/jbmr.1572] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We used Raman and Fourier transform infrared microspectroscopy (FTIRM) analysis to examine the intrinsic bone material properties at actively bone-forming trabecular surfaces in iliac crest biopsies from women with postmenopausal osteoporosis (PMO) who were treated with either alendronate (ALN) or risedronate (RIS). At eight study sites, women were identified who had postmenopausal osteoporosis (PMO), were at least 5 years postmenopause, and had been on long-term therapy (either 3-5 years or >5 years) with daily or weekly ALN or RIS. Following standard tetracycline labeling, biopsies were collected from 102 women (33 treated with ALN for 3-5 years [ALN-3], 35 with ALN for >5 years [ALN-5], 26 with RIS for 3-5 years [RIS-3], and 8 with RIS for >5 years [RIS-5]) and were analyzed at anatomical areas of similar tissue age in bone-forming areas (within the fluorescent double labels). The following outcomes were monitored and reported: mineral to matrix ratio (corresponding to ash weight), relative proteoglycan content (regulating mineralization commencement), mineral maturity (indicative of the mineral crystallite chemistry and stoichiometry, and having a direct bearing on crystallite shape and size), and the ratio of two of the major enzymatic collagen cross-links (pyridinoline/divalent). In RIS-5 there was a significant decrease in the relative proteoglycan content (-5.83% compared to ALN-5), while in both RIS-3 and RIS-5 there was significantly lower mineral maturity/crystallinity (-6.78% and -13.68% versus ALN-3 and ALN-5, respectively), and pyridinoline/divalent collagen cross-link ratio (-23.09% and -41.85% versus ALN-3 and ALN-5, respectively). The results of the present study indicate that ALN and RIS exert differential effects on the intrinsic bone material properties at actively bone-forming trabecular surfaces.
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Roelofs AJ, Stewart CA, Sun S, Błażewska KM, Kashemirov BA, McKenna CE, Russell RGG, Rogers MJ, Lundy MW, Ebetino FH, Coxon FP. Influence of bone affinity on the skeletal distribution of fluorescently labeled bisphosphonates in vivo. J Bone Miner Res 2012; 27:835-47. [PMID: 22228189 DOI: 10.1002/jbmr.1543] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Bisphosphonates are widely used antiresorptive drugs that bind to calcium. It has become evident that these drugs have differing affinities for bone mineral; however, it is unclear whether such differences affect their distribution on mineral surfaces. In this study, fluorescent conjugates of risedronate, and its lower-affinity analogues deoxy-risedronate and 3-PEHPC, were used to compare the localization of compounds with differing mineral affinities in vivo. Binding to dentine in vitro confirmed differences in mineral binding between compounds, which was influenced predominantly by the characteristics of the parent compound but also by the choice of fluorescent tag. In growing rats, all compounds preferentially bound to forming endocortical as opposed to resorbing periosteal surfaces in cortical bone, 1 day after administration. At resorbing surfaces, lower-affinity compounds showed preferential binding to resorption lacunae, whereas the highest-affinity compound showed more uniform labeling. At forming surfaces, penetration into the mineralizing osteoid was found to inversely correlate with mineral affinity. These differences in distribution at resorbing and forming surfaces were not observed at quiescent surfaces. Lower-affinity compounds also showed a relatively higher degree of labeling of osteocyte lacunar walls and labeled lacunae deeper within cortical bone, indicating increased penetration of the osteocyte canalicular network. Similar differences in mineralizing surface and osteocyte network penetration between high- and low-affinity compounds were evident 7 days after administration, with fluorescent conjugates at forming surfaces buried under a new layer of bone. Fluorescent compounds were incorporated into these areas of newly formed bone, indicating that "recycling" had occurred, albeit at very low levels. Taken together, these findings indicate that the bone mineral affinity of bisphosphonates is likely to influence their distribution within the skeleton.
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Błażewska KM, Ni F, Haiges R, Kashemirov BA, Coxon FP, Stewart CA, Baron R, Rogers MJ, Seabra MC, Ebetino FH, McKenna CE. Synthesis, stereochemistry and SAR of a series of minodronate analogues as RGGT inhibitors. Eur J Med Chem 2011; 46:4820-6. [DOI: 10.1016/j.ejmech.2011.04.063] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 04/26/2011] [Accepted: 04/27/2011] [Indexed: 11/30/2022]
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Sugiyama T, Meakin LB, Galea GL, Jackson BF, Lanyon LE, Ebetino FH, Russell RGG, Price JS. Risedronate does not reduce mechanical loading-related increases in cortical and trabecular bone mass in mice. Bone 2011; 49:133-9. [PMID: 21497678 PMCID: PMC3119791 DOI: 10.1016/j.bone.2011.03.775] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 01/07/2023]
Abstract
To establish whether the combination of anti-resorptive therapy with mechanical loading has a negative, additive or synergistic effect on bone structure, we assessed the separate and combined effects of risedronate and non-invasive dynamic loading on trabecular and cortical bone. Seventeen-week-old female C57BL/6 mice were given daily subcutaneous injections of vehicle (n=20) or risedronate at a dose of 0.15, 1.5, 15 or 150 μg/kg/day (n=10 in each) for 17 days. From the fourth day of treatment, the right tibiae were subjected to a single period of axial loading (40 cycles/day) for three alternate days per week for two weeks. The left tibiae were used as internal controls. Trabecular and cortical sites in the tibiae were analyzed by high-resolution micro-computed tomography and imaging of fluorochrome labels. In the non-loaded tibiae, treatment with the higher doses of risedronate at 15 or 150 μg/kg/day resulted in higher trabecular bone volume and trabecular number than in vehicle-treated controls, whereas such treatment was associated with no differences in cortical bone volume at any dose. In the loaded tibiae, loading induced increases in trabecular and cortical bone volume compared with contra-lateral controls primarily through increased trabecular thickness and periosteal expansion, respectively, independently of risedronate treatment. In conclusion, the response to mechanical loading in both trabecular and cortical bone in mice is therefore not impaired by short-term treatment with risedronate, even over a 1000-fold dose range. In considering the optimization of treatments for osteoporosis, it is reassuring that anti-resorptive therapy and mechanical loading can exert independent beneficial effects.
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Ebetino FH, Hogan AML, Sun S, Tsoumpra MK, Duan X, Triffitt JT, Kwaasi AA, Dunford JE, Barnett BL, Oppermann U, Lundy MW, Boyde A, Kashemirov BA, McKenna CE, Russell RGG. The relationship between the chemistry and biological activity of the bisphosphonates. Bone 2011; 49:20-33. [PMID: 21497677 DOI: 10.1016/j.bone.2011.03.774] [Citation(s) in RCA: 275] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 03/29/2011] [Accepted: 03/29/2011] [Indexed: 11/20/2022]
Abstract
The ability of bisphosphonates ((HO)(2)P(O)CR(1)R(2)P(O)(OH)(2)) to inhibit bone resorption has been known since the 1960s, but it is only recently that a detailed molecular understanding of the relationship between chemical structures and biological activity has begun to emerge. The early development of chemistry in this area was largely empirical and based on modifying R(2) groups in a variety of ways. Apart from the general ability of bisphosphonates to chelate Ca(2+) and thus target the calcium phosphate mineral component of bone, attempts to refine clear structure-activity relationships had led to ambiguous or seemingly contradictory results. However, there was increasing evidence for cellular effects, and eventually the earliest bisphosphonate drugs, such as clodronate (R(1)=R(2)=Cl) and etidronate (R(1)=OH, R(2)=CH(3)), were shown to exert intracellular actions via the formation in vivo of drug derivatives of ATP. The observation that pamidronate, a bisphosphonate with R(1)=OH and R(2)=CH(2)CH(2)NH(2), exhibited higher potency than previously known bisphosphonate drugs represented the first step towards the later recognition of the critical importance of having nitrogen in the R(2) side chain. The synthesis and biological evaluation of a large number of nitrogen-containing bisphosphonates took place particularly in the 1980s, but still with an incomplete understanding of their structure-activity relationships. A major advance was the discovery that the anti-resorptive effects of the nitrogen-containing bisphosphonates (including alendronate, risedronate, ibandronate, and zoledronate) on osteoclasts appear to result from their potency as inhibitors of the enzyme farnesyl pyrophosphate synthase (FPPS), a key branch-point enzyme in the mevalonate pathway. FPPS generates isoprenoid lipids utilized in sterol synthesis and for the post-translational modification of small GTP-binding proteins essential for osteoclast function. Effects on other cellular targets, such as osteocytes, may also be important. Over the years many hundreds of bisphosphonates have been synthesized and studied. Interest in expanding the structural scope of the bisphosphonate class has also motivated new approaches to the chemical synthesis of these compounds. Recent chemical innovations include the synthesis of fluorescently labeled bisphosphonates, which has enabled studies of the biodistribution of these drugs. As a class, bisphosphonates share common properties. However, as with other classes of drugs, there are chemical, biochemical, and pharmacological differences among the individual compounds. Differences in mineral binding affinities among bisphosphonates influence their differential distribution within bone, their biological potency, and their duration of action. The overall pharmacological effects of bisphosphonates on bone, therefore, appear to depend upon these two key properties of affinity for bone mineral and inhibitory effects on osteoclasts. The relative contributions of these properties differ among individual bisphosphonates and help determine their clinical behavior and effectiveness.
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Błażewska KM, Haiges R, Kashemirov BA, Ebetino FH, McKenna CE. A serendipitous phosphonocarboxylate complex of boron: when vessel becomes reagent. Chem Commun (Camb) 2011; 47:6395-7. [PMID: 21552630 DOI: 10.1039/c1cc10876j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Under certain conditions, the phosphonocarboxylate analogue (3) of the bisphosphonate drug minodronate (4) in contact with borosilicate glassware reversibly forms an isolable dimer complex of boron, as revealed by the X-ray crystallographic structure of the (R,R/S,S) complex and supported by NMR and HRMS data.
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Sun S, Błażewska KM, Kashemirov BA, Roelofs AJ, Coxon FP, Rogers MJ, Ebetino FH, McKenna MJ, McKenna CE. Synthesis and characterization of novel fluorescent nitrogen-containing bisphosphonate imaging probes for bone active drugs. PHOSPHORUS SULFUR 2011; 186:970-971. [PMID: 21894242 DOI: 10.1080/10426507.2010.526674] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Progress in the synthesis of novel fluorescent conjugates of N-heterocyclic bisphosphonate drugs and related analogues, together with some recent applications of these compounds as imaging probes, are briefly discussed.
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Roelofs AJ, Thompson K, Ebetino FH, Rogers MJ, Coxon FP. Bisphosphonates: molecular mechanisms of action and effects on bone cells, monocytes and macrophages. Curr Pharm Des 2011; 16:2950-60. [PMID: 20722616 DOI: 10.2174/138161210793563635] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 07/12/2010] [Indexed: 11/22/2022]
Abstract
Bisphosphonates are widely used in the treatment of diseases involving excessive bone resorption, such as osteoporosis, cancer-associated bone disease, and Paget's disease of bone. They target to the skeleton due to their calcium-chelating properties, where they primarily act by inhibiting osteoclast-mediated bone resorption. The simple bisphosphonates, clodronate, etidronate and tiludronate, are intracellularly metabolised to cytotoxic ATP analogues, while the more potent, nitrogen-containing bisphosphonates act by inhibiting the enzyme FPP synthase, thereby preventing the prenylation of small GTPases that are necessary for the normal function and survival of osteoclasts. In recent years, these concepts have been refined, with an increased understanding of the exact mode of inhibition of FPP synthase and the consequences of inhibiting this enzyme. Recent studies further suggest that the R2 side chain, as well as determining the potency for inhibiting the target enzyme FPP synthase, also influences bone mineral binding, which may influence distribution within bone and duration of action. While bisphosphonates primarily affect the function of resorbing osteoclasts, it is becoming increasingly clear that bisphosphonates may also target the osteocyte network and prevent osteocyte apoptosis, which could contribute to their anti-fracture effects. Furthermore, increasing evidence implicates monocytes and macrophages as direct targets of bisphosphonate action, which may explain the acute phase response and the anti-tumour activity in certain animal models. Bone mineral affinity is likely to influence the extent of any such effects of these agents on non-osteoclast cells. While alternative anti-resorptive therapeutics are becoming available for clinical use, bisphosphonates currently remain the principle drugs used to treat excessive bone resorption.
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Qiu S, Phipps RJ, Ebetino FH, Palnitkar S, Sudhaker Rao D. Effect of risedronate on osteocyte viability and bone turnover in paired iliac bone biopsies from early postmenopausal women. Calcif Tissue Int 2010; 87:392-7. [PMID: 20809096 DOI: 10.1007/s00223-010-9411-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 08/13/2010] [Indexed: 01/09/2023]
Abstract
It is unclear whether standard clinical doses of risedronate affect osteocyte viability. This study examined osteocyte viability and bone remodeling rate in early postmenopausal women (1-5 years after menopause) who were treated with a standard clinical dose of risedronate (5 mg/day, orally) for 1 year. Paired transiliac bone biopsies were obtained from 19 postmenopausal women at baseline and after 1-year treatment with placebo (n = 8, mean age 52.9 ± 3.4 years) or risedronate 5 mg/day (n = 11, mean age 52.5 ± 3.4 years). In these samples, we measured osteocyte- and bone remodeling-related variables in trabecular bone. In both the placebo and risedronate groups, empty lacunae were significantly decreased after 1-year treatment compared to baseline. There were no significant differences in osteocyte-related variables between placebo and risedronate. Risedronate significantly reduced bone-remodeling indices including mineralizing surface (MS/BS), bone formation rate (BFR/BS), and activation frequency (Ac.f). Risedronate treatment caused significantly lower MS/BS and Ac.f than placebo administration. In conclusion, risedronate 5 mg/day effectively inhibited bone remodeling but did not significantly reduce osteocyte viability in trabecular bone.
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McKenna CE, Kashemirov BA, Błazewska KM, Mallard-Favier I, Stewart CA, Rojas J, Lundy MW, Ebetino FH, Baron RA, Dunford JE, Kirsten ML, Seabra MC, Bala JL, Marma MS, Rogers MJ, Coxon FP. Synthesis, chiral high performance liquid chromatographic resolution and enantiospecific activity of a potent new geranylgeranyl transferase inhibitor, 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid. J Med Chem 2010; 53:3454-64. [PMID: 20394422 DOI: 10.1021/jm900232u] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3-(3-Pyridyl)-2-hydroxy-2-phosphonopropanoic acid (3-PEHPC, 1) is a phosphonocarboxylate (PC) analogue of 2-(3-pyridyl)-1-hydroxyethylidenebis(phosphonic acid) (risedronic acid, 2), an osteoporosis drug that decreases bone resorption by inhibiting farnesyl pyrophosphate synthase (FPPS) in osteoclasts, preventing protein prenylation. 1 has lower bone affinity than 2 and weakly inhibits Rab geranylgeranyl transferase (RGGT), selectively preventing prenylation of Rab GTPases. We report here the synthesis and biological studies of 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid (3-IPEHPC, 3), the PC analogue of minodronic acid 4. Like 1, 3 selectively inhibited Rab11 vs. Rap 1A prenylation in J774 cells, and decreased cell viability, but was 33-60x more active in these assays. After resolving 3 by chiral HPLC (>98% ee), we found that (+)-3-E1 was much more potent than (-)-3-E2 in an isolated RGGT inhibition assay, approximately 17x more potent (LED 3 microM) than (-)-3-E2 in inhibiting Rab prenylation in J774 cells and >26x more active in the cell viability assay. The enantiomers of 1 exhibited a 4-fold or smaller potency difference in the RGGT and prenylation inhibition assays.
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Fu K, Xu Q, Czernuszka J, McKenna CE, Ebetino FH, Russell RGG, Triffitt JT, Xia Z. Prolonged osteogenesis from human mesenchymal stem cells implanted in immunodeficient mice by using coralline hydroxyapatite incorporating rhBMP2 microspheres. J Biomed Mater Res A 2010; 92:1256-64. [PMID: 19322875 DOI: 10.1002/jbm.a.32453] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The local environment plays an important role in osteogenic tissue regeneration. Our previous studies have shown that xenogenic transplantation of human mesenchymal stem cells (hMSCs) alone into immunodeficient mice did not result in long-term bone formation. This study investigates whether bone formation can be prolonged by incorporating human mesenchymal stem cells in mineralized scaffolds together with controlled delivery of a growth factor, BMP2. A composite of coralline hydroxyapatite (CHA) with poly(lactic-co-glycolic acid) (PLGA)-encapsulated rhBMP2 was incorporated with hMSCs in vitro. After 2 weeks in vitro culture the constructs were implanted subcutaneously in CB17 scid beige mice and harvested 10 weeks after implantation. The mineralized tissues were stained by using a fluorescent marker, 5FAM-risedronate, followed by observation with fluorescence microscopy, histology, histomorphometry, mouse-anti-human vimentin immunohistochemistry, and scanning microscopy. The results showed that compared with control materials in which only fibrous tissue formed following implantation of coralline scaffolds, bone-like tissue formed within the CHA composite containing PLGA encapsulated rhBMP2 and hMSCs for up to 10 weeks after implantation. Human cells, identified by the human vimentin-specific monoclonal antibody were seen within the bone-like tissue. In conclusion, incorporation of hMSCs into CHA with controlled delivery of BMP showed prolonged bone formation in immunodeficient mice. Further research is required to optimize the growth factor delivery system and to understand the underlying cellular and molecular mechanisms involved.
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Lawson MA, Xia Z, Barnett BL, Triffitt JT, Phipps RJ, Dunford JE, Locklin RM, Ebetino FH, Russell RGG. Differences between bisphosphonates in binding affinities for hydroxyapatite. J Biomed Mater Res B Appl Biomater 2010; 92:149-55. [PMID: 19904734 DOI: 10.1002/jbm.b.31500] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bisphosphonates (BPs) inhibit bone resorption and are widely used for the treatment of bone diseases, including osteoporosis. BPs are also being studied for their effects on hydroxyapatite (HAP)-containing biomaterials. There is a growing appreciation that there are hitherto unexpected differences among BPs in their mineral binding affinities that affect their pharmacological and biological properties. To study these differences, we have developed a method based on fast performance liquid chromatography using columns of HAP to which BPs and other phosphate-containing compounds can adsorb and be eluted by using phosphate buffer gradients at pH 6.8. The individual compounds emerge as discrete and reproducible peaks for a range of compounds with different affinities. For example, the peak retention times (min; mean +/- SEM) were 22.0 +/- 0.3 for zoledronate, 16.16 +/- 0.44 for risedronate, and 9.0 +/- 0.28 for its phosphonocarboxylate analog, NE10790. These results suggest that there are substantial differences among BPs in their binding to HAP. These differences may be exploited in the development of biomaterials and may also partly explain the extent of their relative skeletal retention and persistence of biological effects observed in both animal and clinical studies.
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Hald A, Hansen RR, Thomsen MW, Ding M, Croucher PI, Gallagher O, Ebetino FH, Kassem M, Heegaard AM. Cancer-induced bone loss and associated pain-related behavior is reduced by risedronate but not its phosphonocarboxylate analog NE-10790. Int J Cancer 2009; 125:1177-85. [PMID: 19444917 DOI: 10.1002/ijc.24436] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Prostate, breast and lung cancers readily develop bone metastases which lead to fractures, hypercalcemia and pain. Malignant growth in the bones depends on osteoclast-mediated bone resorption and in this regard bisphosphonate compounds, which have high-bone affinity and inhibit osteoclast activity, have been found to alleviate bone cancer symptoms. In this study, the bisphosphonate risedronate and its phosphonocarboxylate derivative NE-10790 was tested in a murine bone cancer pain model. Risedronate decreased bone cancer-related bone destruction and pain-related behavior and decreased the spinal expression of glial fibrillary acidic protein, whereas NE-10790 had no effect on these parameters. Furthermore, risedronate but not NE-10790 induced dose-dependent toxicity in NCTC-2472 cells in vitro. Furthermore, the direct toxic effect of risedronate on tumor cells observed in vitro opens the possibility that a direct toxic effect on tumor cells may also be present in vivo and be related to the efficacy of bisphosphonate compounds. In conclusion, these results suggest that risedronate treatment may lead to an increased life quality, in patient suffering from bone cancer, in terms of decreased osteolysis and pain, and merits further study.
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Kashemirov BA, Bala JLF, Chen X, Ebetino FH, Xia Z, Russell RGG, Coxon FP, Roelofs AJ, Rogers MJ, McKenna CE. Fluorescently labeled risedronate and related analogues: "magic linker" synthesis. Bioconjug Chem 2009; 19:2308-10. [PMID: 19032080 DOI: 10.1021/bc800369c] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report synthesis of the first fluorescently labeled conjugates of risedronate (1), using an epoxide linker strategy enabling conjugation of 1 via its pyridyl nitrogen with the label (carboxyfluorescein). Unlike prior approaches to create fluorescent bisphosphonate probes, the new linking chemistry did not abolish the ability to inhibit protein prenylation in vitro, while significantly retaining hydroxyapatite affinity. The utility of a fluorescent 1 conjugate in visualizing osteoclast resorption in vitro was demonstrated.
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Baron RA, Tavaré R, Figueiredo AC, Błazewska KM, Kashemirov BA, McKenna CE, Ebetino FH, Taylor A, Rogers MJ, Coxon FP, Seabra MC. Phosphonocarboxylates inhibit the second geranylgeranyl addition by Rab geranylgeranyl transferase. J Biol Chem 2008; 284:6861-8. [PMID: 19074143 PMCID: PMC2652301 DOI: 10.1074/jbc.m806952200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rab geranylgeranyl transferase (RGGT) catalyzes the post-translational
geranylgeranyl (GG) modification of (usually) two C-terminal cysteines in Rab
GTPases. Here we studied the mechanism of the Rab geranylgeranylation reaction
by bisphosphonate analogs in which one phosphonate group is replaced by a
carboxylate (phosphonocarboxylate, PC). The phosphonocarboxylates used were
3-PEHPC, which was previously reported, and
2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic
acid ((+)-3-IPEHPC), a >25-fold more potent related compound as measured by
both IC50 and Ki.(+)-3-IPEHPC behaves as a
mixed-type inhibitor with respect to GG pyrophosphate (GGPP) and an
uncompetitive inhibitor with respect to Rab substrates. We propose that
phosphonocarboxylates prevent only the second GG transfer onto Rabs based on
the following evidence. First, geranylgeranylation of Rab proteins ending with
a single cysteine motif such as CAAX, is not affected by the
inhibitors, either in vitro or in vivo. Second, the addition
of an -AAX sequence onto Rab-CC proteins protects the substrate from
inhibition by the inhibitors. Third, we demonstrate directly that in the
presence of (+)-3-IPEHPC, Rab-CC and Rab-CXC proteins are modified by
only a single GG addition. The presence of (+)-3-IPEHPC resulted in a
preference for the Rab N-terminal cysteine to be modified first, suggesting an
order of cysteine geranylgeranylation in RGGT catalysis. Our results further
suggest that the inhibitor binds to a site distinct from the GGPP-binding site
on RGGT. We suggest that phosphonocarboxylate inhibitors bind to a GG-cysteine
binding site adjacent to the active site, which is necessary to align the
mono-GG-Rab for the second GG addition. These inhibitors may represent a novel
therapeutic approach in Rab-mediated diseases.
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Fournier PG, Daubiné F, Lundy MW, Rogers MJ, Ebetino FH, Clézardin P. Lowering Bone Mineral Affinity of Bisphosphonates as a Therapeutic Strategy to Optimize Skeletal Tumor Growth Inhibition In vivo. Cancer Res 2008; 68:8945-53. [DOI: 10.1158/0008-5472.can-08-2195] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tian X, Switzer AG, Derose SA, Mishra RK, Solinsky MG, Mumin RN, Ebetino FH, Jayasinghe LR, Webster ME, Colson AO, Crossdoersen D, Pinney BB, Farmer JA, Dowty ME, Obringer CM, Cruze CA, Burklow ML, Suchanek PM, Dong L, Dirr MK, Sheldon RJ, Wos JA. Discovery of Orally Bioavailable 1,3,4-Trisubstituted 2-Oxopiperazine-Based Melanocortin-4 Receptor Agonists as Potential Antiobesity Agents. J Med Chem 2008; 51:6055-66. [DOI: 10.1021/jm800525p] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Russell RGG, Watts NB, Ebetino FH, Rogers MJ. Mechanisms of action of bisphosphonates: similarities and differences and their potential influence on clinical efficacy. Osteoporos Int 2008; 19:733-59. [PMID: 18214569 DOI: 10.1007/s00198-007-0540-8] [Citation(s) in RCA: 941] [Impact Index Per Article: 58.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Accepted: 11/27/2007] [Indexed: 12/12/2022]
Abstract
UNLABELLED Bisphosphonates (BPs) are well established as the leading drugs for the treatment of osteoporosis. There is new knowledge about how they work. The differences that exist among individual BPs in terms of mineral binding and biochemical actions may explain differences in their clinical behavior and effectiveness. INTRODUCTION The classical pharmacological effects of bisphosphonates (BPs) appear to be the result of two key properties: their affinity for bone mineral and their inhibitory effects on osteoclasts. DISCUSSION There is new information about both properties. Mineral binding affinities differ among the clinically used BPs and may influence their differential distribution within bone, their biological potency, and their duration of action. The antiresorptive effects of the nitrogen-containing BPs (including alendronate, risedronate, ibandronate, and zoledronate) appear to result from their inhibition of the enzyme farnesyl pyrophosphate synthase (FPPS) in osteoclasts. FPPS is a key enzyme in the mevalonate pathway, which generates isoprenoid lipids utilized for the post-translational modification of small GTP-binding proteins that are essential for osteoclast function. Effects on other cellular targets, such as osteocytes, may also be important. BPs share several common properties as a drug class. However, as with other families of drugs, there are obvious chemical, biochemical, and pharmacological differences among the individual BPs. Each BP has a unique profile that may help to explain potential clinical differences among them, in terms of their speed and duration of action, and effects on fracture reduction.
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Deprèle S, Kashemirov BA, Hogan JM, Ebetino FH, Barnett BL, Evdokimov A, McKenna CE. Farnesyl pyrophosphate synthase enantiospecificity with a chiral risedronate analog, [6,7-dihydro-5H-cyclopenta[c]pyridin-7-yl(hydroxy)methylene]bis(phosphonic acid) (NE-10501): Synthetic, structural, and modeling studies. Bioorg Med Chem Lett 2008; 18:2878-82. [DOI: 10.1016/j.bmcl.2008.03.088] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 03/22/2008] [Accepted: 03/31/2008] [Indexed: 11/24/2022]
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Ebetino FH. The Discovery of the Bone-Active Agent Risedronate, and Bisphosphonate Structure-Activity Considerations Including the Aminophenylethane Phosphonate Series. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426509908546169] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Almstead NG, Dansereau SM, Francis MD, Snider CM, Ebetino FH. The Design and Synthesis of Sulfur Containing Bisphosphonic Acids for the Treatment of Arthritis. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426509908546247] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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