Steric structure–activity relationship of cyproheptadine derivatives as inhibitors of histone methyltransferase Set7/9

Set7/9 is a histone lysine methyltransferase, but it is also thought to be involved in a wide variety of pathophysiological functions. We previously identified cyproheptadine, which has a characteristic butterfly-like molecular conformation with bent tricyclic dibenzosuberene and chair-form N-methylpiperidine moieties, as a Set7/9 inhibitor. In this work, we synthesized several derivatives in order to examine the steric structure–inhibitory activity relationship. We found that even a small change of molecular shape due to reduction or replacement of the 10,11-olefinic bond of the tricyclic ring generally resulted in a drastic decrease of the inhibitory activity. Our results should be useful not only for development of more potent and selective inhibitors, but also for the construction of novel inhibitor scaffolds.     

Inhibition of Plasmodium falciparum phenylalanine tRNA synthetase provides opportunity for antimalarial drug development

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Discovery of a highly potent,selective and novel CDK9 inhibitor as an anticancer drug candidate

A series of novel hybrid structure derivatives, containing both LEE011 and Cabozantinib pharmacophore, were designed, synthesized and evaluated. Surprisingly, a compound 4d was discovered that highly exhibited effective and selective activity of CDK9 inhibition with IC₅₀ = 12 nM. It effectively induced apoptosis in breast and lung cancer cell lines at nanomolar level. Molecular docking of 4d to ATP binding site of CDK9 kinase demonstrated a new hydrogen bonding between F atom of 4-(3-fluorobenzyloxy) group and ASN116 residue, compared with the positive control, LEE011. The compound 4d could block the cell cycle both in G0/G1 and G2/M phase to prevent the proliferation and differentiation of cancer cells. Mice bared-breast cancer treated with compound 4d showed significant suppression of cancer with low toxicity. Taken together, this novel compound 4d could be a promising drug candidate for clinical application.     

CRISPR-Cas9技术在细菌耐药性防控研究进展

近年来,多种新型耐药基因的出现和全球性流行,严重威胁了全球公众健康.CRISPR-Cas9系统(clustered regularly interspaced short palindromic repeats-CRISPR associated protein 9 system)是细菌的一种适应性免疫系统,可切割耐药...     

Lead optimization and efficacy evaluation of quinazoline-based BET family inhibitors for potential treatment of cancer and inflammatory diseases

Extensive optimization of quinazoline-based lead 8 is described. The structure-activity relationship studies indicate the S-configuration is preferred for the phenylmorpholine substitution. Together with incorporation of a (2-hydroxyl-2-methylpropyl)pyrazole moiety at the 2-position leads to analogs with comparable potency and marked improvement in the pharmacokinetic profile over our previously reported lead compounds. Further in vivo efficacy studies in Kasumi-1 xenograft mouse model demonstrates that the selected inhibitors are well tolerated and highly efficacious in the inhibition of tumor growth. Additionally, the representative analog 19 also demonstrated significant improvement of arthritis severity in a collagen-induced arthritis (CIA) mouse model. These results indicate potential use of these quinazoline-based BET inhibitors for treatment of cancer and inflammatory diseases. A brief discussion of the co-crystallized structure of 19 with BRD4 (BD1) is also highlighted.     

Design,synthesis and biological evaluation of imidazo[1,5-a]pyrazin-8(7H)-one derivatives as BRD9 inhibitors

BRD9 is the subunit of mammalian SWI/SNF chromatin remodeling complex (BAF). SWI/SNF complex mutations were found in nearly 20% of human cancers. The biological role played by BRD9 bromodomain remains poorly understood, and it is therefore imperative to identify potent and highly selective inhibitors to effectively explore the biology of individual bromodomain proteins. In this paper, we synthesized a series of imidazo[1,5-a]pyrazin-8(7H)-one derivatives as potent BRD9 inhibitors and evaluated their BRD9 inhibitory activity in vitro and anti-proliferation effects against tumor cells. Gratifyingly, compound 27 and 29 exhibited robust potency of BRD9 inhibition with IC₅₀ values of 35 and 103?nM respectively. Docking studies were performed to explain the structure-activity relationship. Furthermore, compound 27 potently inhibited cell proliferation in cell lines A549 and EOL-1 with an IC₅₀ value of 6.12?μM and 1.76?μM respectively. The chemical probe, compound 27, was identified that should prove to be useful in further exploring BRD9 bromodomain biology in both in vitro and in vivo settings.     

Inhibition of CRISPR-Cas9 with Bacteriophage Proteins

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Temperature-Responsive Competitive Inhibition of CRISPR-Cas9

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Drug resistance mechanisms and novel drug targets for tuberculosis therapy

Drug-resistant tuberculosis (TB) poses a significant challenge to the successful treatment and control of TB worldwide. Resistance to anti-TB drugs has existed since the beginning of the chemotherapy era. New insights into the resistant mechanisms of anti-TB drugs have been provided. Better understanding of drug resistance mechanisms helps in the development of new tools for the rapid diagnosis of drug-resistant TB. There is also a pressing need in the development of new drugs with novel targets to improve the current treatment of TB and to prevent the emergence of drug resistance in Mycobacterium tuberculosis. This review summarizes the anti-TB drug resistance mechanisms, furnishes some possible novel drug targets in the development of new agents for TB therapy and discusses the usefulness using known targets to develop new anti-TB drugs. Whole genome sequencing is currently an advanced technology to uncover drug resistance mechanisms in M. tuberculosis. However, further research is required to unravel the significance of some newly discovered gene mutations in their contribution to drug resistance.     

临床酵母样真菌的感染特点及耐药性研究

目的了解临床酵母样真菌的感染类型、分布以及耐药情况,为临床诊断治疗提供合理的用药依据.方法采用常规方法进行真菌培养,用科玛嘉显色培养基联合法国生物梅里埃API 20C AUX鉴定条进行鉴定,药敏试验采用微量稀释法.结果864株酵母样真菌中,白色念珠菌619株（71.6%）,其次为热带念珠菌116株（13.4%）和克柔念珠菌47株（5.4%）,非白色念珠菌感染的比例逐年上升（21.5%）.其中,呼吸道标本酵母样真菌检出率最高,达79.7%,其次是消化道为8.8%,泌尿道为4.7%.科室分布依次为干部科、呼吸科、急诊内科、血液科等;白色念珠菌对两性霉素B、5-氟胞嘧啶高度敏感,达90%以上,对氟康唑和伊曲康唑的敏感性有所降低.结论酵母样真菌的检出率与患者基础疾病密切相关;对氟康唑等药物的敏感性有下降的趋势,未发现对4种药物同时耐药的菌株,提示在治疗中,药敏监测是非常必要的.     

CRISPR/Cas9 mediated G4946E substitution in the ryanodine receptor of Spodoptera exigua confers high levels of resistance to diamide insecticides

Diamide insecticides selectively activate insect ryanodine receptors (RyRs), inducing uncontrolled release of calcium ions, and causing muscle contraction, paralysis and eventually death. The RyR^G4946E substitution associated with diamide resistance has been identified in three lepidopteran pests, Plutella xylostella, Tuta absoluta and Chilo suppressalis. Recently, the T. absoluta RyR^G4946V mutation was knocked into the model insect Drosophila melanogaster by CRISPR/Cas9 mediated genome editing and provided in vivo functional confirmation for its role in diamide resistance. In the present study, we successfully introduced the RyR^G4946E mutation with CRISPR/Cas9 technology into a lepidopteran pest of global importance, Spodoptera exigua. The genome-edited strain (named 4946E) homozygous for the SeRyR^G4946E mutation exhibited 223-, 336- and >1000-fold resistance to chlorantraniliprole, cyantraniliprole and flubendiamide, respectively when compared to the wild type strain (WHS) of S. exigua. Reciprocal crossing experiments revealed that the target-site resistance in strain 4946E underlies an autosomal and almost recessive mode of inheritance for anthranilic diamides, whereas it was completely recessive for flubendiamide. Our results not only provided in vivo functional validation of the RyR^G4946E mutation in conferring high levels of resistance to diamide insecticides for the first time in a controlled genetic background of a lepidopteran pest, but also revealed slight differences on the level of resistance between anthranilic diamides (chlorantraniliprole and cyantraniliprole) and flubendiamide conferred by the SeRyR^G4946E mutation.     

糖尿病足感染的细菌学调查及耐药性分析

目的 了解临床糖尿病足患者感染的细菌分布及耐药性分析.方法 2009年至2010年,共调查135例糖尿病足患者.结果 检出细菌株数为107株,其中革兰阳性菌44株,占41.1％;革兰阴性菌57株,占53.3％;真菌6株,占5.6％.需氧菌感染80例,检出率59.3％.以金葡菌、链球菌、变形杆菌和大肠埃希菌为主要感染菌.金黄色葡萄球菌的耐药率明显低于其他葡萄球菌.大肠埃希菌治疗以亚胺培南首选,也可选用β-内酰胺类加酶抑制剂.结论 检出革兰阴性菌57株,革兰阳性菌44株,应根据药敏情况合理应用抗菌素.     

Molecular mechanism study of several inhibitors binding to BRD9 bromodomain based on molecular simulations

Bromodomain-containing protein 9 (BRD9) has been employed as a potential target for anticancer drugs in recent years. In this work, molecular docking, molecular dynamics (MD) simulations, binding free energy calculations, and per residue energy decomposition approaches were performed to elucidate the different binding modes between four pyridinone-like scaffold inhibitors and BRD9 bromodomain. Analysis results indicate that non-polar contribution mainly deriving from van der Waals energy is a critical impact on binding affinity of inhibitors against BRD9. Some key residues Phe44, Phe47, Val49, and Ile53 (at ZA loop) enhance the binding energy of inhibitors in BRD9 by means of providing hydrophobic interactions. Moreover, it is observed that BRD9 is anchored by the formation of a stable hydrogen bond between the carbonyl of the inhibitors and the residue Asn100 (at BC loop), and a strong π–π stacking interaction formed between the residue Tyr106 (at BC loop) and the inhibitors. The existence of dimethoxyphenyl structure and the aromatic ring merged to pyridinone scaffold are useful to enhance the BRD9 binding affinity. These findings should guide the rational design of more prospective inhibitors targeting BRD9.

Communicated by Ramaswamy H. Sarma     

临床常见病原菌的分布及耐药性分析

目的了解我院患者常见病原菌分布及其耐药情况,指导临床治疗,合理使用抗生素。方法将我院2006年~2008年分离的临床病原菌分布及其耐药情况进行回顾性分析。结果我院病原菌分布以革兰阴性杆菌为主,占40.9%,革兰阳性球菌占34.4%,真菌占24.7%,居于革兰阴性杆菌前3位的菌群是大肠埃希菌、变形杆菌属和克雷伯菌属;居于革兰阳性球菌前3位的菌群是凝固酶阴性葡萄球菌、肠球菌属和链球菌属;各菌群中抗菌药物的耐药率均有上升,部分菌株呈多重耐药。结论革兰阴性杆菌已成为医院感染的最常见病原菌,对抗生素耐药日益严重,医院应重视病原菌的耐药性监测,及时掌握细菌耐药的动态,指导临床合理使用抗生素,防止医院感染的发生。     

Glutathione transferases and development of new principles to overcome drug resistance

Chemoresistance is a multifactorial phenomenon and many studies clearly show that a coordinated expression of efflux transporter proteins and phase II conjugating enzymes in tumor cells is linked to the development of the multidrug resistance phenotype. In particular, the overexpression of glutathione S-transferases and efflux pumps in tumors may reduce the reactivity of various anticancer drugs. In recent years it has become evident that glutathione S-transferases are also involved in the control of apoptosis through the inhibition of the JNK signaling pathway. As such, the glutathione S-transferase superfamily has become the focus of extensive pharmaceutical research in attempt to generate more efficient anticancer agents. Here we present an overview of the GST inhibitors and the GST-activated pro-drugs utilized to date to overcome drug resistance.     

伤口分泌物的病原菌分布及耐药性分析

目的调查福建省龙岩市第二医院伤口分泌物病原菌的分布及耐药情况,为合理应用抗生素提供依据。方法收集2012年1月至2013年5月患者伤口分泌物标本,采用常规方法进行分离培养,用VITEK-2 Compact全自动微生物分析仪系统进行鉴定及药敏分析。结果送检503份标本,培养阳性272份,阳性率为54. 1% ;病原菌检出343株,其中革兰阴性菌189株占55. 1%,革兰阳性菌151株占44.0%,真菌3株占0.9% ;前5位的病原菌分别为金黄色葡萄球菌、凝固酶阴性葡萄球菌、铜绿假单胞菌、大肠埃希菌、鲍曼不动杆菌。耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MRCNS）的检出率分别是30.4%、82. 1%。粪肠球菌中耐高浓度氨基糖苷类肠球菌（HLAR）的检出率为55%。革兰阳性菌对万古霉素、替加环素、利奈唑胺未出现耐药菌株。铜绿假单胞菌、肠杆菌科细菌对亚胺培南的耐药率分别为5. 6%、0。大肠埃希菌中超广谱P-内酰胺酶（ESBL）的检出率是42.9%。鲍曼不动杆菌对头孢哌酮/舒巴坦的耐药率最低为25.0%,对其他抗菌药物耐药严重,多数抗菌药物的耐药率均〉45%。结论伤口感染的主要病原菌是革兰阴性菌,多重耐药菌株比例较高,临床应根据药敏结果合理选用抗生素,减少新的耐药菌株出现。     

Epigenetic and pharmacological control of pigmentation via Bromodomain Protein 9 (BRD9)

Lineage-specific differentiation programs are activated by epigenetic changes in chromatin structure. Melanin-producing melanocytes maintain a gene expression program ensuring appropriate enzymatic conversion of metabolites into the pigment, melanin, and transfer to surrounding cells. During neuroectodermal development, SMARCA4 (BRG1), the catalytic subunit of SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes, is essential for lineage specification. SMARCA4 is also required for development of multipotent neural crest precursors into melanoblasts, which differentiate into pigment-producing melanocytes. In addition to the catalytic domain, SMARCA4 and several SWI/SNF subunits contain bromodomains which are amenable to pharmacological inhibition. We investigated the effects of pharmacological inhibitors of SWI/SNF bromodomains on melanocyte differentiation. Strikingly, treatment of murine melanoblasts and human neonatal epidermal melanocytes with selected bromodomain inhibitors abrogated melanin synthesis and visible pigmentation. Using functional genomics, iBRD9, a small molecule selective for the bromodomain of BRD9 was found to repress pigmentation-specific gene expression. Depletion of BRD9 confirmed a requirement for expression of pigmentation genes in the differentiation program from melanoblasts into pigmented melanocytes and in melanoma cells. Chromatin immunoprecipitation assays showed that iBRD9 disrupts the occupancy of BRD9 and the catalytic subunit SMARCA4 at melanocyte-specific loci. These data indicate that BRD9 promotes melanocyte pigmentation whereas pharmacological inhibition of BRD9 is repressive.