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1.
J Med Chem ; 63(10): 5585-5623, 2020 05 28.
Article in English | MEDLINE | ID: mdl-32324999

ABSTRACT

The BET family of proteins consists of BRD2, BRD3, BRD4, and BRDt. Each protein contains two distinct bromodomains (BD1 and BD2). BET family bromodomain inhibitors under clinical development for oncology bind to each of the eight bromodomains with similar affinities. We hypothesized that it may be possible to achieve an improved therapeutic index by selectively targeting subsets of the BET bromodomains. Both BD1 and BD2 are highly conserved across family members (>70% identity), whereas BD1 and BD2 from the same protein exhibit a larger degree of divergence (∼40% identity), suggesting selectivity between BD1 and BD2 of all family members would be more straightforward to achieve. Exploiting the Asp144/His437 and Ile146/Val439 sequence differences (BRD4 BD1/BD2 numbering) allowed the identification of compound 27 demonstrating greater than 100-fold selectivity for BRD4 BD2 over BRD4 BD1. Further optimization to improve BD2 selectivity and oral bioavailability resulted in the clinical development compound 46 (ABBV-744).


Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/metabolism , Drug Discovery/methods , Pyridines/chemistry , Pyridines/metabolism , Pyrroles/chemistry , Pyrroles/metabolism , Transcription Factors/antagonists & inhibitors , Transcription Factors/metabolism , Animals , Female , HeLa Cells , Humans , Mice , Mice, SCID , Protein Domains/drug effects , Protein Domains/physiology , Protein Structure, Secondary , Protein Structure, Tertiary , Pyridines/pharmacology , Pyrroles/pharmacology , Xenograft Model Antitumor Assays/methods
2.
Nature ; 578(7794): 306-310, 2020 02.
Article in English | MEDLINE | ID: mdl-31969702

ABSTRACT

Proteins of the bromodomain and extra-terminal (BET) domain family are epigenetic readers that bind acetylated histones through their bromodomains to regulate gene transcription. Dual-bromodomain BET inhibitors (DbBi) that bind with similar affinities to the first (BD1) and second (BD2) bromodomains of BRD2, BRD3, BRD4 and BRDt have displayed modest clinical activity in monotherapy cancer trials. A reduced number of thrombocytes in the blood (thrombocytopenia) as well as symptoms of gastrointestinal toxicity are dose-limiting adverse events for some types of DbBi1-5. Given that similar haematological and gastrointestinal defects were observed after genetic silencing of Brd4 in mice6, the platelet and gastrointestinal toxicities may represent on-target activities associated with BET inhibition. The two individual bromodomains in BET family proteins may have distinct functions7-9 and different cellular phenotypes after pharmacological inhibition of one or both bromodomains have been reported10,11, suggesting that selectively targeting one of the bromodomains may result in a different efficacy and tolerability profile compared with DbBi. Available compounds that are selective to individual domains lack sufficient potency and the pharmacokinetics properties that are required for in vivo efficacy and tolerability assessment10-13. Here we carried out a medicinal chemistry campaign that led to the discovery of ABBV-744, a highly potent and selective inhibitor of the BD2 domain of BET family proteins with drug-like properties. In contrast to the broad range of cell growth inhibition induced by DbBi, the antiproliferative activity of ABBV-744 was largely, but not exclusively, restricted to cell lines of acute myeloid leukaemia and prostate cancer that expressed the full-length androgen receptor (AR). ABBV-744 retained robust activity in prostate cancer xenografts, and showed fewer platelet and gastrointestinal toxicities than the DbBi ABBV-07514. Analyses of RNA expression and chromatin immunoprecipitation followed by sequencing revealed that ABBV-744 displaced BRD4 from AR-containing super-enhancers and inhibited AR-dependent transcription, with less impact on global transcription compared with ABBV-075. These results underscore the potential value of selectively targeting the BD2 domain of BET family proteins for cancer therapy.


Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/chemistry , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/metabolism , Protein Domains/drug effects , Pyridines/pharmacology , Pyrroles/pharmacology , Transcription Factors/antagonists & inhibitors , Transcription Factors/chemistry , Animals , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Enhancer Elements, Genetic/genetics , Gene Expression Regulation, Neoplastic/drug effects , Humans , Male , Mice , Pyridines/adverse effects , Pyridines/toxicity , Pyrroles/adverse effects , Pyrroles/toxicity , Rats , Receptors, Androgen/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Transcription, Genetic/drug effects , Xenograft Model Antitumor Assays
3.
Bioorg Med Chem Lett ; 28(10): 1804-1810, 2018 06 01.
Article in English | MEDLINE | ID: mdl-29678460

ABSTRACT

Novel conformationally constrained BET bromodomain inhibitors have been developed. These inhibitors were optimized in two similar, yet distinct chemical series, the 6-methyl-1H-pyrrolo[2,3-c]pyridin-7(6H)-ones (A) and the 1-methyl-1H-pyrrolo[2,3-c]pyridin-7(6H)-ones (B). Each series demonstrated excellent activity in binding and cellular assays, and lead compounds from each series demonstrated significant efficacy in in vivo tumor xenograft models.


Subject(s)
Nuclear Proteins/antagonists & inhibitors , Pyridones/chemistry , Transcription Factors/antagonists & inhibitors , Animals , Binding Sites , Cell Cycle Proteins , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Drug Evaluation, Preclinical , Half-Life , Humans , Mice , Microsomes/metabolism , Molecular Dynamics Simulation , Multiple Myeloma/drug therapy , Nuclear Proteins/metabolism , Protein Structure, Tertiary , Pyridones/pharmacokinetics , Pyridones/pharmacology , Pyridones/therapeutic use , Structure-Activity Relationship , Transcription Factors/metabolism , Transplantation, Heterologous
4.
J Med Chem ; 60(20): 8369-8384, 2017 10 26.
Article in English | MEDLINE | ID: mdl-28949521

ABSTRACT

The development of bromodomain and extraterminal domain (BET) bromodomain inhibitors and their examination in clinical studies, particularly in oncology settings, has garnered substantial recent interest. An effort to generate novel BET bromodomain inhibitors with excellent potency and drug metabolism and pharmacokinetics (DMPK) properties was initiated based upon elaboration of a simple pyridone core. Efforts to develop a bidentate interaction with a critical asparagine residue resulted in the incorporation of a pyrrolopyridone core, which improved potency by 9-19-fold. Additional structure-activity relationship (SAR) efforts aimed both at increasing potency and improving pharmacokinetic properties led to the discovery of the clinical candidate 63 (ABBV-075/mivebresib), which demonstrates excellent potency in biochemical and cellular assays, advantageous exposures and half-life both in animal models and in humans, and in vivo efficacy in mouse models of cancer progression and inflammation.


Subject(s)
Drug Discovery , Proteins/antagonists & inhibitors , Pyridones/pharmacology , Sulfonamides/pharmacology , Animals , Cell Line, Tumor , Chromatography, High Pressure Liquid , Fluorescence Resonance Energy Transfer , Half-Life , Humans , Mass Spectrometry , Mice , Proton Magnetic Resonance Spectroscopy , Pyridones/chemistry , Pyridones/pharmacokinetics , Structure-Activity Relationship , Sulfonamides/chemistry , Sulfonamides/pharmacokinetics
5.
Mol Cancer Ther ; 16(8): 1511-1520, 2017 08.
Article in English | MEDLINE | ID: mdl-28468776

ABSTRACT

Ten percent to 15% of all lung cancers are small-cell lung cancer (SCLC). SCLC usually grows and metastasizes before it is diagnosed and relapses rapidly upon treatment. Unfortunately, no new targeted agent has been approved in the past 30 years for patients with SCLC. The BET (bromodomain and extraterminal) proteins bind acetylated histones and recruit protein complexes to promote transcription initiation and elongation. BET proteins have been shown to regulate expression of key genes in oncogenesis, such as MYC, CCND2, and BCL2L1 Here, we demonstrate that approximately 50% of SCLC cell lines are exquisitely sensitive to growth inhibition by the BET inhibitor, ABBV-075. The majority of these SCLC cell lines underwent apoptosis in response to ABBV-075 treatment via induction of caspase-3/7 activity. ABBV-075 enhanced the expression of proapoptotic protein BIM and downregulated antiapoptotic proteins BCL2 and BCLxl to a lesser extent. Furthermore, BET inhibition increased BCL2-BIM complex, thus priming the cells for apoptosis. Indeed, strong synergy was observed both in vitro and in vivo when cotreating the cells with BET inhibitor and the BH3-mimetic, BCL2 inhibitor venetoclax (ABT-199). ABBV-075 interaction with venetoclax positively correlated with BCL2 expression. Taken together, our studies provide a rationale for treating SCLC with BET and BCL2 inhibitors in tumors with high BCL2 protein expression. Mol Cancer Ther; 16(8); 1511-20. ©2017 AACR.


Subject(s)
Apoptosis , Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Lung Neoplasms/drug therapy , Proteins/antagonists & inhibitors , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Pyridones/therapeutic use , Small Cell Lung Carcinoma/drug therapy , Small Cell Lung Carcinoma/pathology , Sulfonamides/therapeutic use , Animals , Apoptosis/drug effects , Bcl-2-Like Protein 11/metabolism , Biomarkers, Tumor/metabolism , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Cell Line, Tumor , Female , Humans , Lung Neoplasms/pathology , Mice, SCID , Proto-Oncogene Proteins c-bcl-2/metabolism , Pyridones/pharmacology , Sulfonamides/pharmacology , Treatment Outcome , Xenograft Model Antitumor Assays , bcl-X Protein/metabolism
6.
J Med Chem ; 60(9): 3828-3850, 2017 05 11.
Article in English | MEDLINE | ID: mdl-28368119

ABSTRACT

Members of the BET family of bromodomain containing proteins have been identified as potential targets for blocking proliferation in a variety of cancer cell lines. A two-dimensional NMR fragment screen for binders to the bromodomains of BRD4 identified a phenylpyridazinone fragment with a weak binding affinity (1, Ki = 160 µM). SAR investigation of fragment 1, aided by X-ray structure-based design, enabled the synthesis of potent pyridone and macrocyclic pyridone inhibitors exhibiting single digit nanomolar potency in both biochemical and cell based assays. Advanced analogs in these series exhibited high oral exposures in rodent PK studies and demonstrated significant tumor growth inhibition efficacy in mouse flank xenograft models.


Subject(s)
Macrocyclic Compounds/chemistry , Macrocyclic Compounds/pharmacology , Pyridones/chemistry , Pyridones/pharmacology , Animals , Crystallography, X-Ray , Drug Discovery , Macrocyclic Compounds/pharmacokinetics , Molecular Structure , Pyridones/pharmacokinetics , Rats , Structure-Activity Relationship
7.
Cancer Res ; 77(11): 2976-2989, 2017 06 01.
Article in English | MEDLINE | ID: mdl-28416490

ABSTRACT

ABBV-075 is a potent and selective BET family bromodomain inhibitor that recently entered phase I clinical trials. Comprehensive preclinical characterization of ABBV-075 demonstrated broad activity across cell lines and tumor models, representing a variety of hematologic malignancies and solid tumor indications. In most cancer cell lines derived from solid tumors, ABBV-075 triggers prominent G1 cell-cycle arrest without extensive apoptosis. In this study, we show that ABBV-075 efficiently triggers apoptosis in acute myeloid leukemia (AML), non-Hodgkin lymphoma, and multiple myeloma cells. Apoptosis induced by ABBV-075 was mediated in part by modulation of the intrinsic apoptotic pathway, exhibiting synergy with the BCL-2 inhibitor venetoclax in preclinical models of AML. In germinal center diffuse large B-cell lymphoma, BCL-2 levels or venetoclax sensitivity predicted the apoptotic response to ABBV-075 treatment. In vivo combination studies uncovered surprising benefits of low doses of ABBV-075 coupled with bortezomib and azacitidine treatment, despite the lack of in vitro synergy between ABBV-075 and these agents. The in vitro/in vivo activities of ABBV-075 described here may serve as a useful reference to guide the development of ABBV-075 and other BET family inhibitors for cancer therapy. Cancer Res; 77(11); 2976-89. ©2017 AACR.


Subject(s)
Androgen Antagonists/therapeutic use , Pyridones/therapeutic use , Sulfonamides/therapeutic use , Androgen Antagonists/pharmacology , Apoptosis , Cell Line, Tumor , Drug Synergism , Humans , Pyridones/pharmacology , Sulfonamides/pharmacology , Transfection
8.
Bioorg Med Chem Lett ; 27(10): 2225-2233, 2017 05 15.
Article in English | MEDLINE | ID: mdl-28268136

ABSTRACT

An NMR fragment screen for binders to the bromodomains of BRD4 identified 2-methyl-3-ketopyrroles 1 and 2. Elaboration of these fragments guided by structure-based design provided lead molecules with significant activity in a mouse tumor model. Further modifications to the methylpyrrole core provided compounds with improved properties and enhanced activity in a mouse model of multiple myeloma.


Subject(s)
Antineoplastic Agents/chemistry , Nuclear Proteins/antagonists & inhibitors , Pyrroles/chemistry , Transcription Factors/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/therapeutic use , Binding Sites , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Drug Design , Half-Life , Humans , Mice , Molecular Dynamics Simulation , Multiple Myeloma/drug therapy , Nuclear Proteins/metabolism , Pyrroles/chemical synthesis , Pyrroles/pharmacokinetics , Pyrroles/therapeutic use , Structure-Activity Relationship , Transcription Factors/metabolism , Transplantation, Heterologous
9.
JAMA Ophthalmol ; 135(2): 96-104, 2017 Feb 01.
Article in English | MEDLINE | ID: mdl-27978569

ABSTRACT

IMPORTANCE: Randomized clinical trials are needed to compare effectiveness and cost-effectiveness of different low-vision (LV) programs. OBJECTIVE: To determine the value of adding LV rehabilitation with a therapist compared with LV services without intervention. DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial was conducted from September 27, 2010, to July 31, 2014, of 323 veterans with macular diseases and best-corrected distance visual acuity (BCDVAbetter-eye) of 20/50 to 20/200. Masked interviewers administered questionnaires by telephone before and after LV treatment. Using an intention-to-treat design, participants were randomized to receive LV devices with no therapy or LV devices with a rehabilitation therapist providing instruction and homework on the use of LV devices, eccentric viewing, and environmental modification. Visual ability was measured in dimensionless log odds units (logits) (0.14-logit change in visual ability corresponds to ability change expected from a 1-line change in visual acuity). INTERVENTIONS: Low-vision devices without therapy and LV devices with therapy. MAIN OUTCOMES AND MEASURES: Comparison of changes (baseline to 4 months) in overall visual ability and in 4 functional domains (reading, visual information, visual motor, and mobility) estimated from responses to the Veterans Affairs Low Vision Visual Functioning Questionnaire (higher scores indicates more ability or less difficulty in performing activities), and comparison of MNREAD changes (baseline to end of treatment) in maximum reading speed, critical print size, and reading acuity (higher number indicates lower visual acuity). RESULTS: Of the 323 participants, 314 were male (97.2%); mean (SD) age, 80 (10.5) years. Basic LV was effective in improving visual ability. However, the LV rehabilitation group improved more in all visual function domains except mobility. Differences were 0.34-logit reading (95% CI, 0.0005 to 0.69; P = .05), 0.27-logit visual information (95% CI, 0.01 to 0.53; P = .04), 0.37-logit visual motor (95% CI, 0.08 to 0.66; P = .01), and 0.27-logit overall (95% CI, 0.06 to 0.49; P = .01). For MNREAD measures, there was more improvement in reading acuity (difference, -0.11 logMAR, 95% CI, -0.15 to -0.07; P < .001) and maximum reading speed (mean increase of 21.0 words/min; 95% CI, 6.4 to 35.5; P = .005), but not critical print size for the LV rehabilitation group (-0.06 logMAR; 95% CI, -0.12 to 0.002; P = .06). In stratified analyses, the LV rehabilitation group with BCDVAbetter-eye worse than 20/63 to 20/200 improved more in visual ability (reading, visual motor, and overall). Differences were 0.56-logit reading ability (95% CI, 0.08-1.04; P = .02), 0.40-logit visual motor (95% CI, 0.03-0.78; P = .04), 0.34-logit overall (95% CI, 0.06-0.62; P = .02). There was no significant difference between treatment groups for those with BCDVAbetter-eye of 20/50 to 20/63. CONCLUSIONS AND RELEVANCE: Both basic LV alone and combined with LV rehabilitation were effective, but the added LV rehabilitation increased the effect only for patients with BCDVAbetter-eye worse than 20/63 to 20/200. Basic LV services may be sufficient for most LV patients with mild visual impairment. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00958360.

10.
Mol Cancer Res ; 15(1): 35-44, 2017 01.
Article in English | MEDLINE | ID: mdl-27707886

ABSTRACT

Competitive inhibitors of acetyl-lysine binding to the bromodomains of the BET (bromodomain and extra terminal) family are being developed for the treatment of solid and hematologic malignancies. The function of BET family member BRD4 at enhancers/superenhancers has been shown to sustain signal-dependent or pathogenic gene expression programs. Here, the hypothesis was tested that the transcription factor drivers of castration-resistant prostate cancer (CRPC) clinical progression, including the androgen receptor (AR), are critically dependent on BRD4 and thus represent a sensitive solid tumor indication for the BET inhibitor ABBV-075. DHT-stimulated transcription of AR target genes was inhibited by ABBV-075 without significant effect on AR protein expression. Furthermore, ABBV-075 disrupted DHT-stimulated recruitment of BET family member BRD4 to gene-regulatory regions cooccupied by AR, including the well-established PSA and TMPRSS2 enhancers. Persistent BET inhibition disrupted the composition and function of AR-occupied enhancers as measured by a reduction in AR and H3K27Ac ChIP signal and inhibition of enhancer RNA transcription. ABBV-075 displayed potent antiproliferative activity in multiple models of resistance to second-generation antiandrogens and inhibited the activity of the AR splice variant AR-V7 and ligand-binding domain gain-of-function mutations, F877L and L702H. ABBV-075 was also a potent inhibitor of MYC and the TMPRSS2-ETS fusion protein, important parallel transcription factor drivers of CRPC. IMPLICATIONS: The ability of BET family inhibitor ABBV-075 to inhibit transcription activation downstream of the initiating events of transcription factors like AR and TMPRSS2:ETS fusion proteins provides a promising therapeutic option for CRPC patients who have developed resistance to second-generation antiandrogens. Mol Cancer Res; 15(1); 35-44. ©2016 AACR.


Subject(s)
Prostatic Neoplasms, Castration-Resistant/pathology , Pyridones/pharmacology , Sulfonamides/pharmacology , Transcription Factors/antagonists & inhibitors , Androgen Antagonists/pharmacology , Animals , Antineoplastic Agents/pharmacology , Benzamides , Cell Line, Tumor , Cell Proliferation/drug effects , Chromatin/metabolism , Dihydrotestosterone/pharmacology , Drug Resistance, Neoplasm/drug effects , Enhancer Elements, Genetic/genetics , Gene Expression Regulation, Neoplastic/drug effects , Humans , Inhibitory Concentration 50 , Ligands , Male , Mice , Nitriles , Phenotype , Phenylthiohydantoin/analogs & derivatives , Phenylthiohydantoin/pharmacology , Prostatic Neoplasms, Castration-Resistant/genetics , Protein Domains , Receptors, Androgen/chemistry , Receptors, Androgen/genetics , Receptors, Androgen/metabolism , Signal Transduction/drug effects , Transcription Factors/metabolism , Transcription, Genetic/drug effects
12.
Mol Cancer Ther ; 12(11): 2308-18, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23943805

ABSTRACT

Successful siRNA therapeutics requires the optimal integration of multiple components, including an efficient delivery system, a disease indication that is appropriate for siRNA-based therapy, and a potent and nontoxic siRNA against a robust therapeutic target. Although all currently available delivery systems have limitations, it is important to recognize that a careful selection of the disease indication, therapeutic target, and siRNA molecule could partially compensate for deficiencies associated with the delivery system and makes it possible to advance a therapeutic siRNA regimen. In this study, we present the development of siRNA therapeutics for hepatocellular carcinoma using an integrated approach, including the development of an efficient lipid nanoparticle delivery system, the identification of a robust therapeutic target that does not trigger liver toxicity upon target knockdown, and the selection of potent and nonimmunogenic siRNA molecules against the target. The resulting siRNA-containing lipid nanoparticles produced significant antitumor efficacy in orthotopic hepatocellular carcinoma models, and, thus, represent a promising starting point for the development of siRNA therapeutics for hepatocellular carcinoma.


Subject(s)
Carcinoma, Hepatocellular/drug therapy , Drug Delivery Systems/methods , Genetic Therapy/methods , Liver Neoplasms/drug therapy , Nanoparticles , RNA, Small Interfering/administration & dosage , Animals , Carcinoma, Hepatocellular/genetics , Cell Line, Tumor , Female , Hep G2 Cells , Humans , Liver Neoplasms/genetics , Liver Neoplasms, Experimental , Mice , Mice, SCID , RNA, Small Interfering/genetics , RNA, Small Interfering/toxicity
13.
Mol Pain ; 7: 39, 2011 May 20.
Article in English | MEDLINE | ID: mdl-21599960

ABSTRACT

BACKGROUND: Intra-articular injection of monosodium iodoacetate (MIA) in the knee joint of rats disrupts chondrocyte metabolism resulting in cartilage degeneration and subsequent nociceptive behavior that has been described as a model of osteoarthritis (OA) pain. Central sensitization through activation of mitogen activated protein kinases (MAPKs) is recognized as a pathogenic mechanism in chronic pain. In the present studies, induction of central sensitization as indicated by spinal dorsal horn MAPK activation, specifically ERK and p38 phosphorylation, was assessed in the MIA-OA model. RESULTS: Behaviorally, MIA-injected rats displayed reduced hind limb grip force 1, 2, and 3 weeks post-MIA treatment. In the same animals, activation of phospho ERK1/2 was gradually increased, reaching a significant level at post injection week 3. Conversely, phosphorylation of p38 MAPK was enhanced maximally at post injection week 1 and decreased, but remained elevated, thereafter. Double labeling from 3-wk MIA rats demonstrated spinal pERK1/2 expression in neurons, but not glia. In contrast, p-p38 was expressed by microglia and a subpopulation of neurons, but not astrocytes. Additionally, there was increased ipsilateral expression of microglia, but not astrocytes, in 3-wk MIA-OA rats. Consistent with increased MAPK immunoreactivity in the contralateral dorsal horn, mechanical allodynia to the contralateral hind-limb was observed 3-wk following MIA. Finally, intrathecal injection of the MEK1 inhibitor PD98059 blocked both reduced hind-limb grip force and pERK1/2 induction in MIA-OA rats. CONCLUSION: Results of these studies support the role of MAPK activation in the progression and maintenance of central sensitization in the MIA-OA experimental pain model.


Subject(s)
Joints/pathology , Mitogen-Activated Protein Kinases/metabolism , Pain/enzymology , Pain/pathology , Spinal Cord/enzymology , Spinal Cord/pathology , Animals , Behavior, Animal/drug effects , Extracellular Signal-Regulated MAP Kinases/metabolism , Flavonoids/pharmacology , Hyperalgesia/complications , Hyperalgesia/pathology , Immunohistochemistry , Injections, Intra-Articular , Iodoacetates/administration & dosage , Joints/drug effects , MAP Kinase Kinase 1/antagonists & inhibitors , MAP Kinase Kinase 1/metabolism , Neuroglia/enzymology , Neuroglia/pathology , Nociceptors/drug effects , Nociceptors/metabolism , Nociceptors/pathology , Osteoarthritis/complications , Osteoarthritis/enzymology , Osteoarthritis/pathology , Pain/chemically induced , Pain/complications , Phenotype , Phosphorylation/drug effects , Posterior Horn Cells/drug effects , Posterior Horn Cells/enzymology , Posterior Horn Cells/pathology , Rats , Spinal Cord/drug effects , p38 Mitogen-Activated Protein Kinases/metabolism
14.
RNA ; 17(4): 603-12, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21321186

ABSTRACT

Delivering small interfering RNA (siRNA) to tumors is the major technical hurdle that prevents the advancement of siRNA-based cancer therapy. One of the difficulties associated with the development of clinically relevant delivery systems is the lack of reliable tools for monitoring siRNA delivery to tumors in vivo. We describe here a novel, positive-readout system where siRNA-mediated target knockdown elicits a rapid and robust increase of reporter activity. Using the positive-readout system, we created (1) ß-galactosidase-based tumor models that allow the detection of target knockdown in 1%-2% of tumor cells and can distinguish between tumor areas where effective target knockdown occurs versus tumor areas that are not accessible to delivery, and (2) luciferase-based tumor models that allow the quantitative assessment of a large number of delivery systems. Using these positive-readout models, we screened a number of literature-described siRNA delivery systems and identified lipid nanoparticles as a promising delivery platform for siRNA-based cancer therapy.


Subject(s)
Gene Knockdown Techniques , Monitoring, Physiologic/methods , Neoplasms/therapy , RNA, Small Interfering/administration & dosage , Animals , Base Sequence , Cell Line, Tumor , Female , Genes, Reporter , Genetic Vectors , Liposomes , Mice , Mice, SCID , Molecular Sequence Data , Nanoparticles/administration & dosage , RNA, Small Interfering/therapeutic use , Xenograft Model Antitumor Assays , beta-Galactosidase/genetics
15.
J Biol Chem ; 282(31): 22765-74, 2007 Aug 03.
Article in English | MEDLINE | ID: mdl-17550900

ABSTRACT

The c-Jun N-terminal kinases (JNKs) have been implicated in the development of insulin resistance, diabetes, and obesity. Genetic disruption of JNK1, but not JNK2, improves insulin sensitivity in diet-induced obese (DIO) mice. We applied RNA interference to investigate the specific role of hepatic JNK1 in contributing to insulin resistance in DIO mice. Adenovirus-mediated delivery of JNK1 short-hairpin RNA (Ad-shJNK1) resulted in almost complete knockdown of hepatic JNK1 protein without affecting JNK1 protein in other tissues. Liver-specific knockdown of JNK1 resulted in significant reductions in circulating insulin and glucose levels, by 57 and 16%, respectively. At the molecular level, JNK1 knockdown mice had sustained and significant increase of hepatic Akt phosphorylation. Furthermore, knockdown of JNK1 enhanced insulin signaling in vitro. Unexpectedly, plasma triglyceride levels were robustly elevated upon hepatic JNK1 knockdown. Concomitantly, expression of proliferator-activated receptor gamma coactivator 1 beta, glucokinase, and microsomal triacylglycerol transfer protein was increased. Further gene expression analysis demonstrated that knockdown of JNK1 up-regulates the hepatic expression of clusters of genes in glycolysis and several genes in triglyceride synthesis pathways. Our results demonstrate that liver-specific knockdown of JNK1 lowers circulating glucose and insulin levels but increases triglyceride levels in DIO mice.


Subject(s)
Gene Expression Regulation, Enzymologic , Glucose/metabolism , Insulin/metabolism , Liver/metabolism , Mitogen-Activated Protein Kinase 8/metabolism , Trans-Activators/biosynthesis , Triglycerides/blood , Adenoviridae/genetics , Adenoviridae/metabolism , Animal Feed , Animals , DNA Primers/chemistry , Mice , Mice, Obese , PPAR gamma/metabolism , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , Phosphorylation , Transcription Factors , Triglycerides/metabolism
16.
Front Biosci ; 12: 3781-94, 2007 May 01.
Article in English | MEDLINE | ID: mdl-17485339

ABSTRACT

Stearoyl-CoA desaturases (SCDs) catalyze the biosynthesis of monounsaturated fatty acids from saturated fatty acids. Four scd genes have been identified in mice and three in human (including one pseudogene). Among the four mouse SCD isoforms, SCD1 is predominantly expressed in liver and adipose tissue. Mice null for the scd1 gene have reduced adiposity, increased energy expenditure and altered lipid profiles. To further evaluate the specific role of hepatic SCD1 and the potential to achieve similar desirable phenotypic changes in adult obese mice, adenovirus-mediated short hairpin interfering RNA (shRNA) was used to acutely knock down hepatic scd1 expression in ob/ob mice. Robust reductions in hepatic SCD1 mRNA and SCD1 enzymatic activity were achieved, sustained up to 2 weeks. Reduced hepatic content of neutral lipids and robust lowering of lipid desaturation indexes, but increased content of liver phosphotidylcholine were observed with SCD1 knockdown. Increased total plasma cholesterol levels were also observed. No significant changes in body weight were observed. Expression levels of several lipogenic and lipid oxidation genes were not significantly altered by short term SCD1 reduction, but UCP2 expression was increased. Our results demonstrate that significant changes to both hepatic and systemic lipid profiles can be achieved through specific knockdown of liver-expressed SCD1 in the ob/ob mouse model. However, hepatic SCD1 knockdown does not result in significant changes in body weight in the short term.


Subject(s)
Fatty Acids/chemistry , Lipids/chemistry , Liver/enzymology , Obesity/enzymology , RNA Interference , Stearoyl-CoA Desaturase/metabolism , Animals , Mice , Obesity/genetics , Reverse Transcriptase Polymerase Chain Reaction
17.
Metabolism ; 56(3): 380-7, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17292727

ABSTRACT

It is unclear how hepatic glucocorticoid receptor (GR) function and hypothalamic-pituitary-adrenal axis tone contribute to the diabetic state and in particular whole-body glucose fluxes. We have previously demonstrated that long-term exposure to hepatic GR inhibition lowers glucose levels in ob/ob mice (J Pharmacol Exp Ther 2005;314:191). The purpose of this study was to determine the effects of a novel GR antagonist (A-348441) on whole-body glucose fluxes in a model of insulin resistance, the Zucker fatty (fa/fa) rat. After an overnight fast, euglycemic-hyperinsulinemic clamp studies were performed 2 hours after single oral dosing as follows: (1) A-348441 at 100 mg/kg or (2) vehicle. Furthermore, effects of 1 week of treatment with either vehicle or A-348441 (3, 10, 30, or 100 mg/kg PO, once per day) were investigated in separate groups of rats fasted overnight and given a final dose of their respective compound, followed 2 hours later by a euglycemic-hyperinsulinemic clamp. One week after catheter implantation, body weight returned to presurgery levels, with no difference between groups. A single, 100-mg/kg dose of A-348441 significantly increased glucose infusion rate 4-fold (P < .05) and reduced endogenous glucose production by 37% (P < .05) but did not change glucose disposal. After 1 week of sub-long-term dosing, fasting glucose levels were reduced dose-dependently with A-348441 vs vehicle (-8%, not significant; -14%, -20%, and -25%, P < .05, at 3, 10, 30, and 100 mg/kg, respectively) with no observed hypoglycemia or change in fasting insulin levels. A-348441 increased the glucose infusion rates after 1-week treatment by 1.3-, 5.7-, 7.3-, and 6.4-fold (P < .05). Endogenous glucose production was decreased (-25%, -44%, -50%, and -61%, P < .05), whereas glucose disposal was increased (29% and 13%, not significant; 23% and 34%, P < .05), with A-348441. In summary, single-dose treatment with the liver-selective GR antagonist A-348441 decreases glucose production with no effect on glucose disposal or fasting glucose levels. After 1 week of treatment with A-348441, (1) there was no effect on body weight, (2) fasting glucose levels decreased, (3) both glucose disposal and glucose infusion rate increased during clamping, and (4) endogenous glucose production was greatly reduced. In addition, hepatic glucose production was highly correlated with fasting glucose levels (r = 0.97). In conclusion, these results indicate that A-348441 increases insulin sensitivity at both the liver and peripheral tissues, leading toward a normalization of the insulin resistant state. Furthermore, with 1-week vs single-dose liver-selective glucocorticoid antagonism, we have determined that the peripheral effect is secondary to the primary event of reduced hepatic glucose production. The approach of inhibiting the hepatic GR may be an advantageous treatment paradigm for individuals with type 2 diabetes mellitus.


Subject(s)
Cholic Acids/pharmacology , Estrone/analogs & derivatives , Glucose/metabolism , Insulin Resistance , Liver/metabolism , Receptors, Glucocorticoid/antagonists & inhibitors , Animals , Blood Glucose/analysis , Dose-Response Relationship, Drug , Estrone/pharmacology , Insulin/blood , Rats , Rats, Zucker
18.
Bioorg Med Chem Lett ; 17(1): 40-4, 2007 Jan 01.
Article in English | MEDLINE | ID: mdl-17070047

ABSTRACT

Libraries of mifepristone analogs, MP-Acids, were designed and synthesized to increase the chances of identifying GR antagonists that possess liver-selective pharmacological profiles. MP-Acids were uniformly potent GR antagonists in binding and in cell-based functional assays. A high throughput pharmacokinetic selection strategy that employs the cassette dosing of MP-Acids was developed to identify liver-targeting compounds. Thus, resource-intensive in vivo assays to measure liver-selective pharmacology were enriched with GR antagonists that achieve high concentrations in the liver.


Subject(s)
Glucocorticoids/chemistry , Glucocorticoids/pharmacokinetics , Liver/metabolism , Mifepristone/analogs & derivatives , Receptors, Glucocorticoid/antagonists & inhibitors , Animals , Glucocorticoids/chemical synthesis , Rats , Rats, Inbred Strains
20.
Bioorg Med Chem Lett ; 16(21): 5555-60, 2006 Nov 01.
Article in English | MEDLINE | ID: mdl-16931002

ABSTRACT

A series of metabolically stable butyrolactam 11beta-HSD1 inhibitors have been synthesized and biologically evaluated. These compounds exhibit excellent HSD1 potency and HSD2 selectivity, pharmacokinetic, and pharmacodynamic profiles.


Subject(s)
11-beta-Hydroxysteroid Dehydrogenase Type 1/antagonists & inhibitors , Lactams/pharmacology , Administration, Oral , Animals , Humans , Lactams/administration & dosage , Lactams/chemical synthesis , Lactams/pharmacokinetics , Metabolic Syndrome/drug therapy , Mice
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