Cullin-RING E3 ligases (CRLs) are the major components of ubiquitin-proteasome system, responsible for ubiquitylation and subsequent degradation of thousands of cellular proteins. CRLs play vital roles in the regulation of multiple cellular processes, including cell cycle, cell apoptosis, DNA replication, signalling transduction among the others, and are frequently dysregulated in many human cancers. The discovery of specific neddylation inhibitors, represented by MLN4924, has validated CRLs as promising targets for anti-cancer therapies with a growing market. Recent studies have focused on the discovery of the CRLs inhibitors by a variety of approaches, including high through-put screen, virtual screen or structure-based drug design. The field is, however, still facing the major challenging, since CRLs are a large multi-unit protein family without typical active pockets to facilitate the drug design, and enzymatic activity is mainly dependent on undruggable protein-protein interactions and dynamic conformation changes. Up to now, most reported CRLs inhibitors are aiming at targeting the F-box family proteins (e.g., SKP2, β-TrCP and FBXW7), the substrate recognition subunit of SCF E3 ligases. Other studies reported few small molecule inhibitors targeting the UBE2M-DCN1 interaction, which specifically inhibits CRL3/CRL1 by blocking the cullin neddylation. On the other hand, several CRL activators have been reported, such as plant auxin and immunomodulatory imide drugs, thalidomide. Finally, proteolysis-targeting chimeras (PROTACs) has emerged as a new technology in the field of drug discovery, specifically targeting the undruggable protein-protein interaction. The technique connects the small molecule that selectively binds to a target protein to a CRL E3 via a chemical linker to trigger the degradation of target protein. The PROTAC has become a hotspot in the field of E3-ligase-based anti-cancer drug discovery.
Antineoplastic Agents ; pharmacology ; therapeutic use ; Drug Design ; Drug Discovery ; Enzyme Inhibitors ; pharmacology ; therapeutic use ; Humans ; Neoplasms ; enzymology ; Ubiquitin-Protein Ligases ; metabolism ; Ubiquitination ; drug effects

Rifamycins, a group of bacterial RNA polymerase inhibitors, are the firstline antimicrobial drugs to treat tuberculosis. In light of the emergence of rifamycinresistant bacteria, development of new RNA polymerase inhibitors that kill rifamycinresistant bacteria with high bioavailability is urgent. Structural analysis of bacterial RNA polymerase in complex with inhibitors by crystallography and cryo-EM indicates that RNA polymerase inhibitors function through five distinct molecular mechanisms:inhibition of the extension of short RNA; competition with substrates; inhibition of the conformational change of the'bridge helix'; inhibition of clamp opening;inhibition of clamp closure. This article reviews the research progress of these five groups of RNA polymerase inhibitors to provide references for the modification of existing RNA polymerase inhibitors and the discovery of new RNA polymerase inhibitors.
Antitubercular Agents ; therapeutic use ; Bacteria ; drug effects ; enzymology ; DNA-Directed RNA Polymerases ; metabolism ; Drug Discovery ; trends ; Drug Resistance, Bacterial ; Enzyme Activation ; drug effects ; Enzyme Inhibitors ; pharmacology ; Humans ; RNA, Bacterial ; Tuberculosis ; drug therapy ; enzymology

Increasing evidence suggests that spinal microglia regulate pathological pain in males. In this study, we investigated the effects of several microglial and astroglial modulators on inflammatory and neuropathic pain following intrathecal injection in male and female mice. These modulators were the microglial inhibitors minocycline and ZVEID (a caspase-6 inhibitor) and the astroglial inhibitors L-α-aminoadipate (L-AA, an astroglial toxin) and carbenoxolone (a connexin 43 inhibitor), as well as U0126 (an ERK kinase inhibitor) and D-JNKI-1 (a c-Jun N-terminal kinase inhibitor). We found that spinal administration of minocycline or ZVEID, or Caspase6 deletion, reduced formalin-induced inflammatory and nerve injury-induced neuropathic pain primarily in male mice. In contrast, intrathecal L-AA reduced neuropathic pain but not inflammatory pain in both sexes. Intrathecal U0126 and D-JNKI-1 reduced neuropathic pain in both sexes. Nerve injury caused spinal upregulation of the astroglial markers GFAP and Connexin 43 in both sexes. Collectively, our data confirmed male-dominant microglial signaling but also revealed sex-independent astroglial signaling in the spinal cord in inflammatory and neuropathic pain.
2-Aminoadipic Acid ; toxicity ; Animals ; Anti-Inflammatory Agents ; therapeutic use ; Astrocytes ; pathology ; Carbenoxolone ; pharmacology ; Caspase 6 ; deficiency ; metabolism ; Connexin 43 ; metabolism ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; pharmacology ; Female ; Glial Fibrillary Acidic Protein ; metabolism ; Male ; Mice ; Mice, Transgenic ; Microglia ; pathology ; Minocycline ; therapeutic use ; Neuralgia ; chemically induced ; drug therapy ; pathology ; Pain Measurement ; Phenylurea Compounds ; pharmacology ; Sex Characteristics ; Spinal Cord ; pathology ; Time Factors

PURPOSE: In this study, we evaluated the long term beneficial effect of Renin-Angiotensin-Aldosterone System (RAAS) blockade therapy in treatment of Marfan aortopathy. MATERIALS AND METHODS: We reviewed Marfan syndrome (MFS) patients who underwent aortic root replacement (ARR) between January 1996 and January 2011. All patients were prescribed beta-blockers indefinitely. We compared major aortic events including mortality, aortic dissection, and reoperation in patients without RAAS blockade (group 1, n=27) to those with (group 2, n=63). The aortic growth rate was calculated by dividing the diameter change on CT scans taken immediately post-operatively and the latest scan available. RESULTS: There were no differences in clinical parameters except for age which was higher in patients with RAAS blockade. In group 1, 2 (7%) deaths, 5 (19%) aortic dissections, and 7 (26%) reoperations occurred. In group 2, 3 (5%) deaths, 2 (3%) aortic dissections, and 3 (5%) reoperations occurred. A Kaplan-Meier plot demonstrated improved survival free from major aortic events in group 2. On multivariate Cox, RAAS blockade was an independent negative predictor of major aortic events (hazard ratio 0.38, 95% confidence interval 0.30-0.43, p=0.002). Mean diameter change in descending thoracic and supra-renal abdominal aorta was significantly higher in patients without RAAS blockade (p<0.05). CONCLUSION: In MFS patients who underwent ARR, the addition of RAAS blockade to beta-blocker was associated with reduction of aortic dilatation and clinical events.
Adrenergic beta-Antagonists/pharmacology ; Aged ; Aneurysm, Dissecting/complications/mortality/surgery ; *Angiotensin Receptor Antagonists ; Angiotensin-Converting Enzyme Inhibitors/*therapeutic use ; Aorta/pathology/*surgery ; Aortic Aneurysm/complications/mortality/surgery ; Aortic Valve ; Female ; Humans ; Male ; Marfan Syndrome/mortality/*surgery ; Middle Aged ; Renin-Angiotensin System/*drug effects

BACKGROUNDRenin-angiotensin system inhibitor and calcium channel blocker (CCB) are widely used in controlling blood pressure (BP) in patients with chronic kidney disease (CKD). We carried out a meta-analysis to compare the renoprotective effect of the combination of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) and CCB (i.e., ACEI/ARB + CCB) with ACEI/ARB monotherapy in patients with hypertension and CKD.

METHODSPublications were identified from PubMed, Embase, Medline, and Cochrane databases. Only randomized controlled trials (RCTs) of BP lowering treatment for patients with hypertension and CKD were considered. The outcomes of end-stage renal disease (ESRD), cardiovascular events, BP, urinary protein measures, estimated glomerular filtration rate (GFR), and adverse events were extracted.

RESULTSBased on seven RCTs with 628 patients, ACEI/ARB + CCB did not show additional benefit for the incidence of ESRD (risk ratio [RR] = 0.84; 95% confidence interval [CI]: 0.52-1.33) and cardiovascular events (RR = 0.58; 95% CI: 0.21-1.63) significantly, compared with ACEI/ARB monotherapy. There were no significant differences in change from baseline to the end points in diastolic BP (weighted mean difference [WMD] = -1.28 mmHg; 95% CI: -3.18 to -0.62), proteinuria (standard mean difference = -0.55; 95% CI: -1.41 to -0.30), GFR (WMD = -0.32 ml/min; 95% CI: -1.53 to -0.89), and occurrence of adverse events (RR = 1.05; 95% CI: 0.72-1.53). However, ACEI/ARB + CCB showed a greater reduction in systolic BP (WMD = -4.46 mmHg; 95% CI: -6.95 to -1.97), compared with ACEI/ARB monotherapy.

CONCLUSIONACEI/ARB + CCB had no additional renoprotective benefit beyond than what could be achieved with ACEI/ARB monotherapy.

Angiotensin Receptor Antagonists ; pharmacology ; therapeutic use ; Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; therapeutic use ; Calcium Channel Blockers ; pharmacology ; therapeutic use ; Drug Therapy, Combination ; Glomerular Filtration Rate ; Humans ; Hypertension ; drug therapy ; Kidney ; drug effects ; Renal Insufficiency, Chronic ; drug therapy

Radiation and drug resistance remain the major challenges and causes of mortality in the treatment of locally advanced, recurrent and metastatic breast cancer. Dysregulation of phospholipase D (PLD) has been found in several human cancers and is associated with resistance to anticancer drugs. In the present study, we evaluated the effects of PLD inhibition on cell survival, cell death and DNA damage after exposure to ionizing radiation (IR). Combined IR treatment and PLD inhibition led to an increase in the radiation-induced apoptosis of MDA-MB-231 metastatic breast cancer cells. The selective inhibition of PLD1 and PLD2 led to a significant decrease in the IR-induced colony formation of breast cancer cells. Moreover, PLD inhibition suppressed the radiation-induced activation of extracellular signal-regulated kinase and enhanced the radiation-stimulated phosphorylation of the mitogen-activated protein kinases p38 and c-Jun N-terminal kinase. Furthermore, PLD inhibition, in combination with radiation, was very effective at inducing DNA damage, when compared with radiation alone. Taken together, these results suggest that PLD may be a useful target molecule for the enhancement of the radiotherapy effect.
Breast Neoplasms/*drug therapy/*enzymology/pathology ; Cell Death/drug effects/radiation effects ; Cell Line, Tumor ; Cell Proliferation/drug effects/radiation effects ; DNA Damage ; Enzyme Activation/drug effects/radiation effects ; Enzyme Inhibitors/*pharmacology/*therapeutic use ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Female ; Humans ; JNK Mitogen-Activated Protein Kinases/metabolism ; Phospholipase D/*antagonists & inhibitors/metabolism ; Radiation Tolerance/*drug effects ; Radiation, Ionizing ; p38 Mitogen-Activated Protein Kinases/metabolism

Ras is best known for its ability to regulate cell growth, proliferation and differentiation. Mutations in Ras are associated with the abnormal cell proliferation which can result in incidence of all human cancers. Extracellular signal-regulated kinase (ERK) is a downstream effector of Ras and plays important roles in prognosis of tumors. Recently, evidence has gradually accumulated to demonstrate that there are other effectors between Ras and ERK, these proteins interact each other and constitute the thorough Ras/Raf/MEK/ERK signaling pathway. The pathway has profound effects on incidence of esophageal carcinoma and clinical applications of some chemotherapeutic drugs targeting the pathway. Further understanding of the relevant molecular mechanisms of Ras/Raf/MEK/ERK signaling pathway can be helpful for the development of efficient targeting therapeutic approaches which contribute to the treatment of esophageal cancer. In this article, roles of Ras/Raf/MEK/ERK signaling pathway in esophageal carcinoma as well as pharmacological targeting point in the pathway are reviewed.
Animals ; Antineoplastic Agents ; pharmacology ; therapeutic use ; Carcinoma, Squamous Cell ; drug therapy ; enzymology ; pathology ; Cell Line, Tumor ; Enzyme Activation ; drug effects ; Esophageal Neoplasms ; drug therapy ; enzymology ; pathology ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; metabolism ; Humans ; Mitogen-Activated Protein Kinase Kinases ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-raf ; antagonists & inhibitors ; metabolism ; Signal Transduction ; drug effects ; ras Proteins ; antagonists & inhibitors ; metabolism

Aurora-B as an important kinase to adjust the cell normal mitosis is a potent target for cancer treatment. Aurora-B is overexpressed in a broad range of tumor and tumor cells are more sensitive while Aurora-B is inhibited. Due to the key role of the Aurora-B in cell mitosis, the development of its inhibitors is becoming more and more important. Several small molecules inhibit with a similar efficacy both Aurora-A and Aurora-B, however, in most cases the effects resemble Aurora-B disruption by genetic methods, indicating that Aurora-B represents an effective therapeutic target. There were several Aurora-B kinase inhibitors which had entered the clinics and displayed good antitumor activity. In this review, we will outline the functions of Aurora kinase B in normal cell division and in malignancy. We will focus on recent preclinical and clinical studies that have explored the mechanism of action and clinical effect of Aurora-B inhibitors in cancer treatment.
Animals ; Aurora Kinase B ; antagonists & inhibitors ; genetics ; metabolism ; Enzyme Activation ; Humans ; Mitosis ; Neoplasms ; drug therapy ; Protein Kinase Inhibitors ; pharmacology ; therapeutic use ; RNA, Messenger ; metabolism

Multidrug-resistant (MDR) bacterial infections, especially those caused by Gram-negative pathogens, have emerged to be one of the world's greatest health threats. However, not only have recent decades shown a steady decline in the number of approved antimicrobial agents but a disappointing discovery also void. The development of novel antibiotics to treat MDR Gram-negative bacteria has been stagnated over the last half century. Though few compounds have shown activities in vitro, in animal models or even in clinical studies, the global antibiotic pipeline is not encouraging. There are a plethora of unexpected challenges that may arise and cannot always be solved to cause promising drugs to fail. This review intends to summarize recent research and development activities to meet the inevitable challenge in restricting the proliferation of MDR Gram-negative bacteria, with focus on compounds that have entered into clinical development stage. In addition to new analogues of existing antibiotic molecules, attention is also directed to alternative strategies to develop antibacterial agents with novel mechanisms of action.
Aminoglycosides ; pharmacology ; therapeutic use ; Animals ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Antibodies, Monoclonal ; pharmacology ; therapeutic use ; Drug Discovery ; Drug Resistance, Multiple, Bacterial ; Enzyme Inhibitors ; pharmacology ; therapeutic use ; Ferrous Compounds ; pharmacology ; therapeutic use ; Gram-Negative Bacteria ; drug effects ; Gram-Negative Bacterial Infections ; drug therapy ; Humans ; Peptides ; pharmacology ; therapeutic use ; Peptidomimetics ; pharmacology ; therapeutic use ; Tetracyclines ; pharmacology ; therapeutic use ; beta-Lactamase Inhibitors ; beta-Lactams ; pharmacology ; therapeutic use

INTRODUCTIONEfavirenz is an inducer of drug metabolism enzymes. We studied the effect of efavirenz and ritonavir-boosted darunavir on serum unconjugated and conjugated bilirubin, as probes for UGT1A1 and bile transporters.

MATERIALS AND METHODSHealthy volunteers were enrolled in a clinical trial. There were 3 periods: Period 1, 10 days of darunavir 900 mg with ritonavir 100 mg once daily; Period 2, 14 days of efavirenz 600 mg with darunavir/ritonavir once daily; and Period 3, 14 days of efavirenz 600 mg once daily. Serum bilirubin (conjugated and unconjugated) concentrations were obtained at baseline, at the end of each phase and at exit.

RESULTSWe recruited 7 males and 5 females. One subject developed grade 3 hepatitis on efavirenz and was excluded. Mean serum unconjugated bilirubin concentrations were 6.09 μmol/L (95% confidence interval [CI], 4.99 to 7.19) at baseline, 5.82 (95% CI, 4.88 to 6.76) after darunavir/ritonavir, 4.00 (95% CI, 2.92 to 5.08) after darunavir/ritonavir with efavirenz, 3.55 (95% CI, 2.58 to 4.51) after efavirenz alone and 5.27 (95% CI, 3.10 to 7.44) at exit (P <0.01 for the efavirenz phases). Mean serum conjugated bilirubin concentrations were 3.55 μmol/L (95% CI, 2.73 to 4.36) at baseline, 3.73 (95% CI, 2.77 to 4.68) after darunavir/ritonavir, 2.91 (95% CI, 2.04 to 3.78) after darunavir/ritonavir with efavirenz, 2.64 (95% CI, 1.95 to 3.33) after efavirenz alone and 3.55 (95% CI, 2.19 to 4.90) at exit (P <0.05 for the efavirenz phases).

CONCLUSIONEfavirenz decreased unconjugated bilirubin by 42%, suggesting UGT1A1 induction. Efavirenz also decreased conjugated bilirubin by 26%, suggesting induction of bile efflux transporters. Ritonavir-boosted darunavir had no effect on bilirubin concentrations. These results indicate that efavirenz may reduce concentrations of drugs or endogenous substances metabolized by UGT1A1 or excreted by bile efflux transporters.

Adult ; Aged ; Anti-HIV Agents ; therapeutic use ; Benzoxazines ; pharmacology ; Biological Transport ; Confidence Intervals ; Darunavir ; Dose-Response Relationship, Drug ; Drug Interactions ; Enzyme Induction ; drug effects ; Female ; Glucuronosyltransferase ; biosynthesis ; blood ; HIV Infections ; drug therapy ; HIV Protease Inhibitors ; Humans ; Incidental Findings ; Male ; Membrane Transport Proteins ; drug effects ; metabolism ; Middle Aged ; Ritonavir ; pharmacology ; Sulfonamides ; pharmacology ; Young Adult