Bachovchin WW

References (16)

Title : Preclinical Development of PNT6555, a Boronic Acid-Based, Fibroblast Activation Protein-alpha (FAP)-Targeted Radiotheranostic for Imaging and Treatment of FAP-Positive Tumors - Poplawski_2023_J.Nucl.Med__
Author(s) : Poplawski SE , Hallett RM , Dornan MH , Novakowski KE , Pan S , Belanger AP , Nguyen QD , Wu W , Felten AE , Liu Y , Ahn SH , Hergott VS , Jones B , Lai JH , McCann JAB , Bachovchin WW
Ref : J Nucl Med , : , 2023
Abstract : The overexpression of fibroblast activation protein-alpha (FAP) in solid cancers relative to levels in normal tissues has led to its recognition as a target for delivering agents directly to tumors. Radiolabeled quinoline-based FAP ligands have established clinical feasibility for tumor imaging, but their therapeutic potential is limited due to suboptimal tumor retention, which has prompted the search for alternative pharmacophores. One such pharmacophore is the boronic acid derivative N-(pyridine-4-carbonyl)-d-Ala-boroPro, a potent and selective FAP inhibitor (FAPI). In this study, the diagnostic and therapeutic (theranostic) potential of N-(pyridine-4-carbonyl)-d-Ala-boroPro-based metal-chelating DOTA-FAPIs was evaluated. Methods: Three DOTA-FAPIs, PNT6555, PNT6952, and PNT6522, were synthesized and characterized with respect to potency and selectivity toward soluble and cell membrane FAP; cellular uptake of the Lu-chelated analogs; biodistribution and pharmacokinetics in mice xenografted with human embryonic kidney cell-derived tumors expressing mouse FAP; the diagnostic potential of (68)Ga-chelated DOTA-FAPIs by direct organ assay and small-animal PET; the antitumor activity of (177)Lu-, (225)Ac-, or (161)Tb-chelated analogs using human embryonic kidney cell-derived tumors expressing mouse FAP; and the tumor-selective delivery of (177)Lu-chelated DOTA-FAPIs via direct organ assay and SPECT. Results: DOTA-FAPIs and their (nat)Ga and (nat)Lu chelates exhibited potent inhibition of human and mouse sources of FAP and greatly reduced activity toward closely related prolyl endopeptidase and dipeptidyl peptidase 4. (68)Ga-PNT6555 and (68)Ga-PNT6952 showed rapid renal clearance and continuous accumulation in tumors, resulting in tumor-selective exposure at 60 min after administration. (177)Lu-PNT6555 was distinguished from (177)Lu-PNT6952 and (177)Lu-PNT6522 by significantly higher tumor accumulation over 168 h. In therapeutic studies, all 3 (177)Lu-DOTA-FAPIs exhibited significant antitumor activity at well-tolerated doses, with (177)Lu-PNT6555 producing the greatest tumor growth delay and animal survival. (225)Ac-PNT6555 and (161)Tb-PNT6555 were similarly efficacious, producing 80% and 100% survival at optimal doses, respectively. Conclusion: PNT6555 has potential for clinical translation as a theranostic agent in FAP-positive cancer.
ESTHER : Poplawski_2023_J.Nucl.Med__
PubMedSearch : Poplawski_2023_J.Nucl.Med__
PubMedID: 38050111

Title : Fibroblast activation protein is dispensable for control of glucose homeostasis and body weight in mice - Panaro_2019_Mol.Metab_19_65
Author(s) : Panaro BL , Coppage AL , Beaudry JL , Varin EM , Kaur K , Lai JH , Wu W , Liu Y , Bachovchin WW , Drucker DJ
Ref : Mol Metab , 19 :65 , 2019
Abstract : OBJECTIVE: Fibroblast Activation Protein (FAP), an enzyme structurally related to dipeptidyl peptidase-4 (DPP-4), has garnered interest as a potential metabolic drug target due to its ability to cleave and inactivate FGF-21 as well as other peptide substrates. Here we investigated the metabolic importance of FAP for control of body weight and glucose homeostasis in regular chow-fed and high fat diet-fed mice. METHODS: FAP enzyme activity was transiently attenuated using a highly-specific inhibitor CPD60 and permanently ablated by genetic inactivation of the mouse Fap gene. We also assessed the FAP-dependence of CPD60 and talabostat (Val-boroPro), a chemical inhibitor reportedly targeting both FAP and dipeptidyl peptidase-4 RESULTS: CPD60 robustly inhibited plasma FAP activity with no effect on DPP-4 activity. Fap gene disruption was confirmed by assessment of genomic DNA, and loss of FAP enzyme activity in plasma and tissues. CPD60 did not improve lipid tolerance but modestly improved acute oral and intraperitoneal glucose tolerance in a FAP-dependent manner. Genetic inactivation of Fap did not improve glucose or lipid tolerance nor confer resistance to weight gain in male or female Fap(-/-) mice fed regular chow or high-fat diets. Moreover, talabostat markedly improved glucose homeostasis in a FAP- and FGF-21-independent, DPP-4 dependent manner. CONCLUSION: Although pharmacological FAP inhibition improves glucose tolerance, the absence of a metabolic phenotype in Fap(-/-)mice suggest that endogenous FAP is dispensable for the regulation of murine glucose homeostasis and body weight. These findings highlight the importance of characterizing the specificity and actions of FAP inhibitors in different species and raise important questions about the feasibility of mouse models for targeting FAP as a treatment for diabetes and related metabolic disorders.
ESTHER : Panaro_2019_Mol.Metab_19_65
PubMedSearch : Panaro_2019_Mol.Metab_19_65
PubMedID: 30477988

Title : DPP8 and DPP9 inhibition induces pro-caspase-1-dependent monocyte and macrophage pyroptosis - Okondo_2017_Nat.Chem.Biol_13_46
Author(s) : Okondo MC , Johnson DC , Sridharan R , Go EB , Chui AJ , Wang MS , Poplawski SE , Wu W , Liu Y , Lai JH , Sanford DG , Arciprete MO , Golub TR , Bachovchin WW , Bachovchin DA
Ref : Nat Chemical Biology , 13 :46 , 2017
Abstract : Val-boroPro (Talabostat, PT-100), a nonselective inhibitor of post-proline cleaving serine proteases, stimulates mammalian immune systems through an unknown mechanism of action. Despite this lack of mechanistic understanding, Val-boroPro has attracted substantial interest as a potential anticancer agent, reaching phase 3 trials in humans. Here we show that Val-boroPro stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. We demonstrate that the inhibition of two serine proteases, DPP8 and DPP9, activates the pro-protein form of caspase-1 independent of the inflammasome adaptor ASC. Activated pro-caspase-1 does not efficiently process itself or IL-1beta but does cleave and activate gasdermin D to induce pyroptosis. Mice lacking caspase-1 do not show immune stimulation after treatment with Val-boroPro. Our data identify what is to our knowledge the first small molecule that induces pyroptosis and reveals a new checkpoint that controls the activation of the innate immune system.
ESTHER : Okondo_2017_Nat.Chem.Biol_13_46
PubMedSearch : Okondo_2017_Nat.Chem.Biol_13_46
PubMedID: 27820798
Gene_locus related to this paper: human-DPP8 , human-DPP9

Title : Neuropeptide Y is a physiological substrate of fibroblast activation protein: Enzyme kinetics in blood plasma and expression of Y2R and Y5R in human liver cirrhosis and hepatocellular carcinoma - Wong_2016_Peptides_75_80
Author(s) : Wong PF , Gall MG , Bachovchin WW , McCaughan GW , Keane FM , Gorrell MD
Ref : Peptides , 75 :80 , 2016
Abstract : Fibroblast activation protein (FAP) is a dipeptidyl peptidase (DPP) and endopeptidase that is weakly expressed in normal adult human tissues but is greatly up-regulated in activated mesenchymal cells of tumors and chronically injured tissue. The identities and locations of target substrates of FAP are poorly defined, in contrast to the related protease DPP4. This study is the first to characterize the physiological substrate repertoire of the DPP activity of endogenous FAP present in plasma. Four substrates, neuropeptide Y (NPY), peptide YY, B-type natriuretic peptide and substance P, were analyzed by mass spectrometry following proteolysis in human or mouse plasma, and by in vivo localization in human liver tissues with cirrhosis and hepatocellular carcinoma (HCC). NPY was the most efficiently cleaved substrate of both human and mouse FAP, whereas all four peptides were efficiently cleaved by endogenous DPP4, indicating that the in vivo degradomes of FAP and DPP4 differ. All detectable DPP-specific proteolysis and C-terminal processing of these neuropeptides was attributable to FAP and DPP4, and plasma kallikrein, respectively, highlighting their combined physiological significance in the regulation of these neuropeptides. In cirrhotic liver and HCC, NPY and its receptor Y2R, but not Y5R, were increased in hepatocytes near the parenchymal-stromal interface where there is an opportunity to interact with FAP expressed on nearby activated mesenchymal cells in the stroma. These novel findings provide insights into the substrate specificity of FAP, which differs greatly from DPP4, and reveal a potential function for FAP in neuropeptide regulation within liver and cancer biology.
ESTHER : Wong_2016_Peptides_75_80
PubMedSearch : Wong_2016_Peptides_75_80
PubMedID: 26621486

Title : A pan inhibitor of DASH family enzymes induces immunogenic modulation and sensitizes murine and human carcinoma cells to antigen-specific cytotoxic T lymphocyte killing: implications for combination therapy with cancer vaccines - Donahue_2014_Vaccine_32_3223
Author(s) : Donahue RN , Duncan BB , Fry TJ , Jones B , Bachovchin WW , Kiritsy CP , Lai JH , Wu W , Zhao P , Liu Y , Tsang KY , Hodge JW
Ref : Vaccine , :3223 , 2014
Abstract : Recent studies have suggested that pan inhibitors of dipeptidyl peptidase-4 activity and/or structure homologs (DASH), including ARI-4175, can mediate tumor regression by immune-mediated mechanisms. This study assessed the potential of combining ARI-4175 with cancer vaccines. We evaluated ARI-4175's effect on immunogenic modulation, ability to sensitize tumor cells to antigen-specific CTL killing, effect on immune-cell subsets and function, and antitumor activity in 2 tumor models, both as a monotherapy and in combination with a recombinant viral or dendritic cell (DC)-based tumor-cell vaccine. ARI-4175's effects on the growth, surface phenotype, and antigen-specific CTL-mediated lysis of murine and human carcinoma cell lines were assessed in vitro. In vivo, C57BL-6 mice were treated orally with ARI-4175, after which splenocytes were assessed by flow cytometry and functional assays. Antitumor studies were performed in murine models of colon carcinoma (MC38-CEA+ in CEA-transgenic C57BL-6 mice) and rhabdomyosarcoma (M3-9-M in C57BL-6 mice). Mice received oral ARI-4175 alone or in combination with a vaccine consisting of recombinant vaccinia/fowlpox CEA-TRICOM (colon model) or a DC-based tumor-cell vaccine (rhabdomyosarcoma model). Exposure to ARI-4175 had no effect on the proliferation or viability of carcinoma cells in vitro; however, it did alter tumor phenotype, making murine and human tumor cells more sensitive to antigen-specific CTL killing. Assessment of immune-cell subsets and function indicated that ARI-4175 increased levels of natural killer cells and DCs. Detrimental immune effects, including reduced T effector cells and increased immunosuppressive cells (Tregs, MDSCs), were normalized when treatment stopped, suggesting that scheduling is critical when combining this agent with vaccine. As a monotherapy, ARI-4175 had potent antitumor activity in both tumor models, and had even greater effects when combined with a vaccine (either DC-based or poxviral vector based). These findings provide the rationale for the combined use of cancer immunotherapy with DASH enzyme inhibitors such as ARI-4175.
ESTHER : Donahue_2014_Vaccine_32_3223
PubMedSearch : Donahue_2014_Vaccine_32_3223
PubMedID: 24731809

Title : A high-throughput, multiplexed assay for superfamily-wide profiling of enzyme activity - Bachovchin_2014_Nat.Chem.Biol_10_656
Author(s) : Bachovchin DA , Koblan LW , Wu W , Liu Y , Li Y , Zhao P , Woznica I , Shu Y , Lai JH , Poplawski SE , Kiritsy CP , Healey SE , DiMare M , Sanford DG , Munford RS , Bachovchin WW , Golub TR
Ref : Nat Chemical Biology , 10 :656 , 2014
Abstract : The selectivity of an enzyme inhibitor is a key determinant of its usefulness as a tool compound or its safety as a drug. Yet selectivity is never assessed comprehensively in the early stages of the drug discovery process, and only rarely in the later stages, because technical limitations prohibit doing otherwise. Here, we report EnPlex, an efficient, high-throughput method for simultaneously assessing inhibitor potency and specificity, and pilot its application to 96 serine hydrolases. EnPlex analysis of widely used serine hydrolase inhibitors revealed numerous previously unrecognized off-target interactions, some of which may help to explain previously confounding adverse effects. In addition, EnPlex screening of a hydrolase-directed library of boronic acid- and nitrile-containing compounds provided structure-activity relationships in both potency and selectivity dimensions from which lead candidates could be more effectively prioritized. Follow-up of a series of dipeptidyl peptidase 4 inhibitors showed that EnPlex indeed predicted efficacy and safety in animal models. These results demonstrate the feasibility and value of high-throughput, superfamily-wide selectivity profiling and suggest that such profiling can be incorporated into the earliest stages of drug discovery.
ESTHER : Bachovchin_2014_Nat.Chem.Biol_10_656
PubMedSearch : Bachovchin_2014_Nat.Chem.Biol_10_656
PubMedID: 24997602
Gene_locus related to this paper: human-PPME1

Title : Identification of selective and potent inhibitors of fibroblast activation protein and prolyl oligopeptidase - Poplawski_2013_J.Med.Chem_56_3467
Author(s) : Poplawski SE , Lai JH , Li Y , Jin Z , Liu Y , Wu W , Wu Y , Zhou Y , Sudmeier JL , Sanford DG , Bachovchin WW
Ref : Journal of Medicinal Chemistry , 56 :3467 , 2013
Abstract : Fibroblast activation protein (FAP) is a serine protease selectively expressed on reactive stromal fibroblasts of epithelial carcinomas. It is widely believed to play a role in tumor invasion and metastasis and therefore to represent a potential new drug target for cancer. Investigation into its biological function, however, has been hampered by the current unavailability of selective inhibitors. The challenge has been in identifying inhibitors that are selective for FAP over both the dipeptidyl peptidases (DPPs), with which it shares exopeptidase specificity, and prolyl oligopeptidase (PREP), with which it shares endopeptidase specificity. Here, we report the first potent FAP inhibitor with selectivity over both the DPPs and PREP, N-(pyridine-4-carbonyl)-d-Ala-boroPro (ARI-3099, 6). We also report a similarly potent and selective PREP inhibitor, N-(pyridine-3-carbonyl)-Val-boroPro (ARI-3531, 22). Both are boronic acid based inhibitors, demonstrating that high selectivity can be achieved using this electrophile. The inhibitors are stable, easy to synthesize, and should prove to be useful in helping to elucidate the biological functions of these two unique and interesting enzymes, as well as their potential as drug targets.
ESTHER : Poplawski_2013_J.Med.Chem_56_3467
PubMedSearch : Poplawski_2013_J.Med.Chem_56_3467
PubMedID: 23594271

Title : Quantitation of fibroblast activation protein (FAP)-specific protease activity in mouse, baboon and human fluids and organs - Keane_2013_FEBS.Open.Bio_4_43
Author(s) : Keane FM , Yao TW , Seelk S , Gall MG , Chowdhury S , Poplawski SE , Lai JH , Li Y , Wu W , Farrell P , Vieira de Ribeiro AJ , Osborne B , Yu DM , Seth D , Rahman K , Haber P , Topaloglu AK , Wang C , Thomson S , Hennessy A , Prins J , Twigg SM , McLennan SV , McCaughan GW , Bachovchin WW , Gorrell MD
Ref : FEBS Open Bio , 4 :43 , 2013
Abstract : The protease fibroblast activation protein (FAP) is a specific marker of activated mesenchymal cells in tumour stroma and fibrotic liver. A specific, reliable FAP enzyme assay has been lacking. FAP's unique and restricted cleavage of the post proline bond was exploited to generate a new specific substrate to quantify FAP enzyme activity. This sensitive assay detected no FAP activity in any tissue or fluid of FAP gene knockout mice, thus confirming assay specificity. Circulating FAP activity was approximately 20- and 1.3-fold less in baboon than in mouse and human plasma, respectively. Serum and plasma contained comparable FAP activity. In mice, the highest levels of FAP activity were in uterus, pancreas, submaxillary gland and skin, whereas the lowest levels were in brain, prostate, leukocytes and testis. Baboon organs high in FAP activity included skin, epididymis, bladder, colon, adipose tissue, nerve and tongue. FAP activity was greatly elevated in tumours and associated lymph nodes and in fungal-infected skin of unhealthy baboons. FAP activity was 14- to 18-fold greater in cirrhotic than in non-diseased human liver, and circulating FAP activity was almost doubled in alcoholic cirrhosis. Parallel DPP4 measurements concorded with the literature, except for the novel finding of high DPP4 activity in bile. The new FAP enzyme assay is the first to be thoroughly characterised and shows that FAP activity is measurable in most organs and at high levels in some. This new assay is a robust tool for specific quantitation of FAP enzyme activity in both preclinical and clinical samples, particularly liver fibrosis.
ESTHER : Keane_2013_FEBS.Open.Bio_4_43
PubMedSearch : Keane_2013_FEBS.Open.Bio_4_43
PubMedID: 24371721

Title : Design and synthesis of boronic acid inhibitors of endothelial lipase - O'Connell_2012_Bioorg.Med.Chem.Lett_22_1397
Author(s) : O'Connell DP , LeBlanc DF , Cromley D , Billheimer J , Rader DJ , Bachovchin WW
Ref : Bioorganic & Medicinal Chemistry Lett , 22 :1397 , 2012
Abstract : Endothelial lipase (EL) and lipoprotein lipase (LPL) are homologous lipases that act on plasma lipoproteins. EL is predominantly a phospholipase and appears to be a key regulator of plasma HDL-C. LPL is mainly a triglyceride lipase regulating (V)LDL levels. The existing biological data indicate that inhibitors selective for EL over LPL should have anti-atherogenic activity, mainly through increasing plasma HDL-C levels. We report here the synthesis of alkyl, aryl, or acyl-substituted phenylboronic acids that inhibit EL. Many of the inhibitors evaluated proved to be nearly equally potent against both EL and LPL, but several exhibited moderate to good selectivity for EL.
ESTHER : O'Connell_2012_Bioorg.Med.Chem.Lett_22_1397
PubMedSearch : O'Connell_2012_Bioorg.Med.Chem.Lett_22_1397
PubMedID: 22225633

Title : 4-Substituted boro-proline dipeptides: synthesis, characterization, and dipeptidyl peptidase IV, 8, and 9 activities - Wu_2012_Bioorg.Med.Chem.Lett_22_5536
Author(s) : Wu W , Liu Y , Milo LJ, Jr. , Shu Y , Zhao P , Li Y , Woznica I , Yu G , Sanford DG , Zhou Y , Poplawski SE , Connolly BA , Sudmeier JL , Bachovchin WW , Lai JH
Ref : Bioorganic & Medicinal Chemistry Lett , 22 :5536 , 2012
Abstract : The boroProline-based dipeptidyl boronic acids were among the first DPP-IV inhibitors identified, and remain the most potent known. We introduced various substitutions at the 4-position of the boroProline ring regioselectively and stereoselectively, and incorporated these aminoboronic acids into a series of 4-substituted boroPro-based dipeptides. Among these dipeptidyl boronic acids, Arg-(4S)-boroHyp (4q) was the most potent inhibitor of DPP-IV, DPP8 and DPP9, while (4S)-Hyp-(4R)-boroHyp (4o) exhibited the most selectivity for DPP-IV over DPP8 and DPP9.
ESTHER : Wu_2012_Bioorg.Med.Chem.Lett_22_5536
PubMedSearch : Wu_2012_Bioorg.Med.Chem.Lett_22_5536
PubMedID: 22853995

Title : Pro-soft Val-boroPro: a strategy for enhancing in vivo performance of boronic acid inhibitors of serine proteases - Poplawski_2011_J.Med.Chem_54_2022
Author(s) : Poplawski SE , Lai JH , Sanford DG , Sudmeier JL , Wu W , Bachovchin WW
Ref : Journal of Medicinal Chemistry , 54 :2022 , 2011
Abstract : Val-boroPro, 1, is a potent, but relatively nonspecific inhibitor of the prolyl peptidases. It has antihyperglycemic activity from inhibition of DPPIV but also striking anticancer activity and a toxicity for which the mechanisms are unknown. 1 cyclizes at physiological pH, which attenuates its inhibitory potency >100-fold, which is a "soft drug" effect. Here we show that this phenomenon can be exploited to create prodrugs with unique properties and potential for selective in vivo targeting. Enzyme-mediated release delivers 1 to the target in the active form at physiological pH; cyclization attenuates systemic pharmacological effects from subsequent diffusion. This "pro-soft" design is demonstrated with a construct activated by and targeted to DPPIV, including in vivo results showing improved antihyperglycemic activity and reduced toxicity relative to 1. Pro-soft derivatives of 1 can help to illuminate the mechanisms underlying the three biological activities, or to help localize 1 at a tumor and thereby lead to improved anticancer agents with reduced toxicity. The design concept can also be applied to a variety of other boronic acid inhibitors.
ESTHER : Poplawski_2011_J.Med.Chem_54_2022
PubMedSearch : Poplawski_2011_J.Med.Chem_54_2022
PubMedID: 21388136

Title : Dipeptide boronic acid inhibitors of dipeptidyl peptidase IV: determinants of potency and in vivo efficacy and safety - Connolly_2008_J.Med.Chem_51_6005
Author(s) : Connolly BA , Sanford DG , Chiluwal AK , Healey SE , Peters DE , Dimare MT , Wu W , Liu Y , Maw H , Zhou Y , Li Y , Jin Z , Sudmeier JL , Lai JH , Bachovchin WW
Ref : Journal of Medicinal Chemistry , 51 :6005 , 2008
Abstract : Dipeptidyl peptidase IV (DPP-IV; E.C. 3.4.14.5), a serine protease that degrades the incretin hormones GLP-1 and GIP, is now a validated target for the treatment of type 2 diabetes. Dipeptide boronic acids, among the first, and still among the most potent DPP-IV inhibitors known, suffer from a concern over their safety. Here we evaluate the potency, in vivo efficacy, and safety of a selected set of these inhibitors. The adverse effects induced by boronic acid-based DPP-IV inhibitors are essentially limited to what has been observed previously for non-boronic acid inhibitors and attributed to cross-reactivity with DPP8/9. While consistent with the DPP8/9 hypothesis, they are also consistent with cross-reactivity with some other intracellular target. The results further show that the potency of simple dipeptide boronic acid-based inhibitors can be combined with selectivity against DPP8/9 in vivo to produce agents with a relatively wide therapeutic index (>500) in rodents.
ESTHER : Connolly_2008_J.Med.Chem_51_6005
PubMedSearch : Connolly_2008_J.Med.Chem_51_6005
PubMedID: 18783201

Title : Synthesis and characterization of constrained peptidomimetic dipeptidyl peptidase IV inhibitors: amino-lactam boroalanines - Lai_2007_J.Med.Chem_50_2391
Author(s) : Lai JH , Wu W , Zhou Y , Maw HH , Liu Y , Milo LJ, Jr. , Poplawski SE , Henry GD , Sudmeier JL , Sanford DG , Bachovchin WW
Ref : Journal of Medicinal Chemistry , 50 :2391 , 2007
Abstract : We describe here the epimerization-free synthesis and characterization of a new class of conformationally constrained lactam aminoboronic acid inhibitors of dipeptidyl peptidase IV (DPP IV; E.C. 3.4.14.5). These compounds have the advantage that they cannot undergo the pH-dependent cyclization prevalent in most dipeptidyl boronic acids that attenuates their potency at physiological pH. For example, D-3-amino-1-[L-1-boronic-ethyl]-pyrrolidine-2-one (amino-D-lactam-L-boroAla), one of the best lactam inhibitors of DPP IV, is several orders of magnitude less potent than L-Ala-L-boroPro, as measured by Ki values (2.3 nM vs 30 pM, respectively). At physiological pH, however, it is actually more potent than L-Ala-L-boroPro, as measured by IC50 values (4.2 nM vs 1400 nM), owing to the absence of the potency-attenuating cyclization. In an interesting and at first sight surprising reversal of the relationship between stereochemistry and potency observed with the conformationally unrestrained Xaa-boroPro class of inhibitors, the L-L diastereomers of the lactams are orders of magnitude less effective than the D-L lactams. However, this interesting reversal and the unexpected potency of the D-L lactams as DPP IV inhibitors can be understood in structural terms, which is explained and discussed here.
ESTHER : Lai_2007_J.Med.Chem_50_2391
PubMedSearch : Lai_2007_J.Med.Chem_50_2391
PubMedID: 17458948

Title : Solution structures of active and inactive forms of the DP IV (CD26) inhibitor Pro-boroPro determined by NMR spectroscopy - Sudmeier_1994_Biochemistry_33_12427
Author(s) : Sudmeier JL , Gunther UL , Gutheil WG , Coutts SJ , Snow RJ , Barton RW , Bachovchin WW
Ref : Biochemistry , 33 :12427 , 1994
Abstract : Synthesis of the boronic acid analog of the dipeptide Pro-Pro yields a mixture of diastereomers Pro-L-boroPro and Pro-D-boroPro, one of which is a potent inhibitor [Ki = 16 pM; Gutheil, W. G., & Bachovchin, W. W. (1993) Biochemistry 32, 8723-8731] of dipeptidyl amino peptidase type IV (DP IV), also known as CD26. The structures of both diasteremers are determined here in aqueous solution by means of 1D and 2D NMR of 1H, 13C, and 11B, and force-field calculations, and the inhibitor is proven to have the L-L configuration. At low pH values (approximately 2), both diastereomers are trans with respect to the peptide bond. Populations of proline ring conformers are determined by pseudorotation analysis, using vicinal proton spin-coupling constants obtained by computer analysis of 1D1H NMR spectral fine structure. At neutral pH values, the Pro-boroPro inhibitor of DP IV undergoes slow, reversible inactivation (Gutheil & Bachovchin, 1993). By structural determination of the decomposition products of both diasteromers, the process is shown here to involve formation of a six-membered ring between the residues by means of trans-cis conversion and formation of a B-N bond, producing chiral nitrogen atoms in both cases having the S configuration. Analogy to cyclic dipeptides suggests the new compounds be named cyclo(Pro-L-boroPro) and cyclo(Pro-D-boroPro).
ESTHER : Sudmeier_1994_Biochemistry_33_12427
PubMedSearch : Sudmeier_1994_Biochemistry_33_12427
PubMedID: 7918465

Title : Dipeptidyl peptidase IV (DP IV) activity in serum and on lymphocytes of MRL\/Mp-lpr\/lpr mice correlates with disease onset - Kubota_1994_Clin.Exp.Immunol_96_292
Author(s) : Kubota T , Iizuka H , Bachovchin WW , Stollar BD
Ref : Clinical & Experimental Immunology , 96 :292 , 1994
Abstract : DP IV (CD26), a serine protease expressed on activated T cells, participates in immune responses in vivo as well as in vitro. We measured cell surface and serum DP IV in mice of the autoimmune MRL/Mp-lpr/lpr (MRL/l) strain, which is characterized by massive T cell proliferation and production of anti-nuclear autoantibodies. The mass of inguinal lymph nodes correlated with serum DP IV activity. Furthermore, serum DP IV activity increased markedly in parallel with the acceleration of lymph node swelling and anti-nDNA antibody production. Serum DP IV activity in 16-week-old MRL/l mice reached levels up to three higher than those in age-matched MRL/Mp- +/+ mice or BALB/c mice. Immunohistochemical staining and flow cytometric analysis identified DV IV on surfaces of lymphocytes from the enlarged lymph nodes of MRL/l mice. Subcutaneous injection of the mechanism-based inhibitor, Pro-boroPro, reduced protease activity in serum and cell suspensions prepared from spleen and lymph nodes, confirming the identity of the enzyme as DP IV. These results indicate that the massively accumulating lymphocytes of MRL/l mice have a property characteristic of activated T cells, although they express little surface CD4 or CD8 and do not produce IL-2. DP IV may participate in the role these cells play in the pathogenesis of MRL/l autoimmune disease.
ESTHER : Kubota_1994_Clin.Exp.Immunol_96_292
PubMedSearch : Kubota_1994_Clin.Exp.Immunol_96_292
PubMedID: 7910536

Title : Separation of L-Pro-DL-boroPro into its component diastereomers and kinetic analysis of their inhibition of dipeptidyl peptidase IV. A new method for the analysis of slow, tight-binding inhibition - Gutheil_1993_Biochemistry_32_8723
Author(s) : Gutheil WG , Bachovchin WW
Ref : Biochemistry , 32 :8723 , 1993
Abstract : The potent dipeptidyl peptidase IV (DP IV) inhibitor [1-(2-pyrrolidinylcarbonyl)-2-pyrrolidinyl]boronic acid (L-Pro-DL-boroPro) [Flentke, G. R., Munoz, E., Huber, B. T., Plaut, A. G., Kettner, C. A., & Bachovchin, W. W. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 1556-1559] was fractionated into its component L-L and L-D diastereomers by C18 HPLC, and the binding of the purified diastereomers to DP IV was analyzed. Inhibition kinetics confirms that the L-L diastereomer is a potent inhibitor of DP IV, having a Ki of 16 pM. The L-D isomer binds at least 1000-fold more weakly than the L-L, if it binds at all, as the approximately 200-fold weaker inhibition observed for the purified L-D isomer is shown here to be due entirely to the presence of a small amount (0.59%) of the L-L diastereomer contaminating the L-D preparation. The instability of Pro-boroPro, together with its very high affinity for DP IV and the time dependence of the inhibition, makes a rigorous kinetic analysis of its binding to DP IV difficult. Here we have developed a method which takes advantage of the slow rate at which the inhibitor dissociates from the enzyme. The method involves preincubating the enzyme and the inhibitor without substrate and then assaying the free enzyme by the addition of substrate and following its hydrolysis for a period of time which is short relative to the dissociation rate of the inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)
ESTHER : Gutheil_1993_Biochemistry_32_8723
PubMedSearch : Gutheil_1993_Biochemistry_32_8723
PubMedID: 8103356