Prospects for novel antiepileptic drugs

The currently available antiepileptic drugs (AEDs) provide a satisfactory level of seizure control in up to 70% of patients with epilepsy. The rational use of these drugs implies a precise syndromic diagnosis and a good familiarity with the clinical pharmacology and tolerability of the AEDs. Significant advances in drug tolerability have occurred in the last 15 years with the development of newer antiepileptic agents that are targeted to cellular epileptogenic mechanisms and have fewer side effects. As a result of integrated molecular and neurophysiological research strategies, further advances in the pharmacological treatment of epilepsy may lead to the design of more selectively tailored AEDs, which will reduce the proportion of drug refractory patients and counteract the development of the epileptogenic process.     

作用于Bcl-2家族抗凋亡亚族蛋白的小分子抑制剂的研究进展

细胞的凋亡是维持机体平衡的重要因素。细胞凋亡由一系列细胞因子调控。Bcl-2蛋白家族是细胞凋亡的关键性调节因子。Bcl-2家族分为抗凋亡和促凋亡两个亚族，他们的相互作用对细胞凋亡信号传导起调控作用。很多肿瘤细胞高表达Bcl-2抗凋亡亚族成员Bcl-2/Bcl-xL。近年来，随着Bcl-2家族各成员的晶体结构相继阐明，人们开始寻找作用于Bcl-2家族抗凋亡亚族蛋白的小分子抑制剂。本文从药物设计角度对该方面的进展作一综述。     

Prospects for the development of novel anti-hyperlipidemic drugs

Hyperlipidemia is a well-established risk factor for atherogenesis and cardiovascular disease. Statins have been the cornerstone of treatment for hyperlipidemia in recent years and have significantly contributed to the improvement of cardiovascular disease therapy. However, novel antihyperlipidemic agents that have been developed over the last decade possess the capacity to significantly reduce plasma lipoproteins. This review analyzes the pharmacological profile, effectiveness and safety of some promising drugs that are either already in clinical use (eg, ezetimibe and nicotinic acid) or under study (eg, acyl-CoA cholesterol acyltransferase inhibitors, cholesteryl ester transfer protein inhibitors and apolipoprotein A-IMilano).     

Small-molecule inhibitors of Bcl-2 family proteins as therapeutic agents in cancer

This review focuses on the recent patents and use of small-molecule inhibitors (SMIs) of Bcl-2 family proteins as therapeutic agents against cancer. Bcl-2 members are crucial regulators of apoptotic cell death. Apoptosis is an evolutionarily conserved process of programmed cell death that plays an essential role in organism development and tissue homeostasis. Several mechanisms exist allowing cells to escape programmed cell death among them is the overexpression of the antiapoptotic proteins. Cancer cells are often found to overexpress many of these members such as Bcl-2, Bcl-X(L), Mcl-1, Bcl-w and A1/Bfl1 and are usually resistant to a wide range of anti-cancer drugs and treatments. Many groups have been working to develop anti-cancer drugs that block the function of anti-apoptotic Bcl-2 members, thus favoring cell death. Methods include the downregulation of Bcl-2 expression or the use of peptides or small organic molecules to the Bcl-2 binding pocket, preventing its sequestration of proapoptotic proteins such as Bid and Bim. One of the most promising aspects of SMIs in treating cancer is that their targets and mechanisms of action are different from those of cytotoxic drugs and radiation. This makes it feasible to combine SMIs with other treatments, creating a synergistic therapy, without likely development of cross-resistance or increased toxicity. A broad-spectrum or "pan" SMI which targets multiple Bcl-2 family proteins is the goal.     

凋亡调节蛋白Bcl-2家族在非小细胞肺癌中的表达

目的在手术切除的原发性非小细胞肺癌(NSCLC)标本中检测凋亡调节蛋白Bcl-2家族中的Bcl-2、Bax和Mcl-1的表达特征和预后的意义。方法用针对人体的Bcl-2、Bax与Mcl-1的特异性鼠源性抗体采用免疫组化法,检测它们在50例NSCLC患者手术切除的石蜡包埋标本中的表达情况,并结合临床病理分型和追踪预后分析其表达的意义。结果(1)非小细胞性肺癌标本中抗凋亡因子Bcl-2和Mcl-1分别有15例(30%)和29例(58%)表达阳性,有23例(46%)的标本中有促凋亡因子Bax表达阳性。Mcl-1与Bax的表达之间存在正相关(P=0.06)。Bcl-2、Bax和Mcl-1的免疫组化染色以胞浆为主。(2)Mcl-1与Bax在肺癌的不同临床病理分型中没有差异(分别为P>0.250和P>0.900)。(3)Bcl-2的表达与原发性NSCLC手术切除患者总的无复发生存率(P=0.02)和无转移生存率(P<0.01)呈负相关,Mcl-1与Bax的表达与预后无关。结论在NSCLC中,Bcl-2家族蛋白Bcl-2、Mcl-1和Bax的表达等都很常见。Mcl-1的抗凋亡功能可能是通过在蛋白质水平与Bax相互作用形成异二聚体,拮抗Bax的促进凋亡功能而实现的。可能由于它们在凋亡中复杂的相互作用,凋亡调节蛋白Bcl-2家族的表达对NSCLC的临床预后没有直接的影响。     

Therapeutic potential for novel drugs targeting the type 1 cholecystokinin receptor

Cholecystokinin (CCK) is a physiologically important gastrointestinal and neuronal peptide hormone, with roles in stimulating gallbladder contraction, pancreatic secretion, gastrointestinal motility and satiety. CCK exerts its effects via interactions with two structurally related class I guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs), the CCK₁ receptor and the CCK₂ receptor. Here, we focus on the CCK₁ receptor, with particular relevance to the broad spectrum of signalling initiated by activation with the natural full agonist peptide ligand, CCK. Distinct ligand-binding pockets have been defined for the natural peptide ligand and for some non-peptidyl small molecule ligands. While many CCK₁ receptor ligands have been developed and have had their pharmacology well described, their clinical potential has not yet been fully explored. The case is built for the potential importance of developing more selective partial agonists and allosteric modulators of this receptor that could have important roles in the treatment of common clinical syndromes.This article is part of a themed section on Molecular Pharmacology of GPCR. To view the editorial for this themed section visit http://dx.doi.org/10.1111/j.1476-5381.2010.00695.x     

A novel approach to develop anti-HIV drugs: adapting non-nucleoside anticancer chemotherapeutics

Some anticancer drugs, but not all, inhibit replication of human immunodeficiency virus (HIV) and thus, exhibit a therapeutic potential. Such drugs, unlike the traditional HIV enzyme inhibitors, could suppress HIV strains that are resistant to inhibitors of viral enzymes, decrease proviral burden in vivo, or reduce reservoirs of infection via killing infected cells. Thus, they may be an effective adjunct therapy or perhaps result in a cure. The incidence of HIV infection and AIDS mortalities continue to increase worldwide, including the United States and parts of Africa, with a parallel increase in a number of other manifestations, including AIDS defining malignancies. The basis for continual spread of HIV presumably in large part stems from the viral resistance to previously successful drugs and the lack of curative antiretroviral drugs. To reverse these trends, other approaches for AIDS therapy must be developed. One possibility is the development of potent anticancer drugs, that exhibit anti-HIV activities. At least four chemically and pharmacologically distinct classes of anticancer drugs, i.e. certain cyclin-dependent kinase inhibitors (CDKIs), topoisomerase 1 enzyme (top 1) inhibitors, non-nucleoside antimetabolites, and estrogen receptor ligands are promising candidates. These drugs, at high doses are used for cancer therapy; at lower concentrations they exhibit anti-HIV activities in cultured cells. While the antiretroviral and the anticancer activities of the cdk inhibitor flavopiridol appear to be mutually exclusive and unrelated in cells and animal model(s) of HIV disease, the top 1 inhibitor 9-nitrocamptothecin, as well as the cdk-inhibitor roscovitine inhibit replication of HIV via selective sensitization of HIV-infected cells to apoptosis. In contrast, the inhibitory effects of these compounds are different from other cancer therapeutics that, at toxic concentrations, activate HIV either in cultured cells (such as certain ingenol and butyrate derivatives) and/or in patients (such as the widely used cyclophosmamide and cisplatin). This quality may lead to the eradication of proviral reservoirs, which is not accomplished by the currently available antiretroviral drugs. In this review, relevant available clinical and in vitro data that either support or discourage using certain anticancer drugs for treatment of HIV disease, and the rationales for developing novel antiretroviral drugs that may target infected cells rather than viral proteins are discussed.     

Dexamethasone differentially regulates Bcl-2 family proteins in human proliferative chondrocytes: Role of pro-apoptotic Bid

Glucocorticoids (GCs) are widely used to treat inflammatory diseases and cancers. A multitude of undesired side effects have been reported in GC-treated patients including decreased linear bone growth. We have previously reported that GCs activate the caspase cascade and trigger Bax-mediated mitochondrial apoptosis in growth plate chondrocytes causing growth retardation in young mice. To further explore the role of mitochondrial apoptosis in GC-induced bone growth retardation, a number of pro- and anti-apoptotic proteins were studied in ex vivo cultures of human growth plate cartilage and human HCS-2/8 proliferative chondrocytes exposed to dexamethasone. Dexamethasone was found to increase the pro-apoptotic proteins Bcl-xS, Bad, and Bak as well as the proteolysis of Bid. Anti-Bid small interfering RNA partially rescued the chondrocytes from dexamethasone-induced apoptosis. Taken together, our data suggest that GC treatment differentially regulates Bcl-2 family member proteins to facilitate mitochondrial apoptosis in proliferative chondrocytes thereby contributing to GC-induced bone growth impairment. Prevention of this imbalance between pro- and anti-apoptotic Bcl-2 family proteins may provide a new strategy to protect from adverse effects of GCs on bone growth.     

Computer aided drug design approaches to develop cyclooxygenase based novel anti-inflammatory and anti-cancer drugs

Cyclooxygenases (COXs), the enzymes involved in the formation of prostaglandins from polyunsaturated fatty acids such as arachidonic acid, exist in two forms--the constitutive COX-1 that is cytoprotective and responsible for the production of prostaglandins and COX-2 which is induced by cytokines, mitogens and endotoxins in inflammatory cells and responsible for the increased levels of prostaglandins during inflammation. As a result COX-2 has become the natural target for the development of anti-inflammatory and anti-cancer drugs. While the conventional NSAIDs with gastric side effects inhibit both COX-1 and COX-2, the newly developed drugs for inflammation with no gastric side effects selectively block the COX-2 enzyme. NSAIDs, nonselective non-aspirin NSAIDs and COX-2 selective inhibitors, are being widely used for various arthritis and pain syndromes. Selective inhibitors of COX-2, however, convey a small but definite risk of myocardial infarction and stroke; the extent of which varies depending on the COX-2 specificity. In view of the gastric side effects of conventional NSAIDs and the recent market withdrawal of rofecoxib and valdecoxib due to their adverse cardiovascular side effects there is need to develop alternative anti-inflammatory agents with reduced gastric and cardiovascular problems. The present study reviews various Computer Aided Drug Design (CADD) approaches to develop Cyclooxygenase based anti-inflammatory and anti-cancer drugs.     

Bcl-2在缺血性神经细胞损伤中的作用及药物的影响

Bcl-2基因是线虫c-elegans的抗凋亡基因Ced-9的人类同源基因,可参与调控细胞凋亡过程,包括抑制脑缺血半影区的神经细胞凋亡。该文就Bcl-2抗缺血性神经细胞损伤的作用和可能机制,以及抗脑缺血药物对Bcl-2的影响作一综述。     

HepDirect prodrugs for targeting nucleotide-based antiviral drugs to the liver

HepDirect prodrugs represent a novel class of cytochrome P450-activated prodrugs capable of targeting certain drugs to the liver. In this review, the HepDirect prodrug concept and its use for the delivery of nucleotides to the liver for the treatment of viral hepatitis is summarized. Preclinical and clinical data for the most advanced HepDirect prodrug, pradefovir, highlight the liver-targeting capability of these prodrugs, and the potential benefit of liver targeting on drug efficacy, safety and viral resistance.     

ApoG2 inhibits antiapoptotic Bcl-2 family proteins and induces mitochondria-dependent apoptosis in human lymphoma U937 cells

Lymphoma is one of the most common types of hematological malignancies and proteins from the Bcl-2 family are highly expressed in human lymphomas. Apogossypolone (ApoG2), the most potent gossypol derivative, has been classified as a novel small-molecule inhibitor of antiapoptotic Bcl-2 family proteins. Here, we assessed the in-vitro cytotoxicity of ApoG2 on human U937 lymphoma cells, and explored the underlying intracellular molecular mechanisms of ApoG2. Using the WST-8 assay, we found that ApoG2 inhibited growth of U937 cells in a dose-dependent and time-dependent manner, and the IC50 values were 30.08, 14.81, and 9.26 mumol/l for 24, 48, and 72 h treatments, respectively. ApoG2 also induced apoptosis in U937 cells, as noted through changes in morphological characteristics, including cellular internucleosomal DNA fragmentation and the appearance of a sub-G1 apoptotic peak. Treatment with ApoG2 downregulated Bcl-xL and Mcl-1 protein expression and blocked the binding of Bcl-2 with Bax protein. Furthermore, ApoG2 led to an abundant release of cytochrome c from mitochondria and a five-fold increase in the activity of caspase-3 and caspase-9. Taken together, our results suggest that ApoG2 could effectively suppress the growth of human lymphoma cell line U937 through the inhibition of the antiapoptotic Bcl-2 family proteins and the induction of mitochondria-dependent apoptotic cell death.     

Proof of concept study to develop a novel connectivity-based electric-field modelling approach for individualized targeting of transcranial magnetic stimulation treatment

Resting state functional connectivity (rsFC) offers promise for individualizing stimulation targets for transcranial magnetic stimulation (TMS) treatments. However, current targeting approaches do not account for non-focal TMS effects or large-scale connectivity patterns. To overcome these limitations, we propose a novel targeting optimization approach that combines whole-brain rsFC and electric-field (e-field) modelling to identify single-subject, symptom-specific TMS targets. In this proof of concept study, we recruited 91 anxious misery (AM) patients and 25 controls. We measured depression symptoms (MADRS/HAMD) and recorded rsFC. We used a PCA regression to predict symptoms from rsFC and estimate the parameter vector, for input into our e-field augmented model. We modeled 17 left dlPFC and 7 M1 sites using 24 equally spaced coil orientations. We computed single-subject predicted ΔMADRS/HAMD scores for each site/orientation using the e-field augmented model, which comprises a linear combination of the following elementwise products (1) the estimated connectivity/symptom coefficients, (2) a vectorized e-field model for site/orientation, (3) rsFC matrix, scaled by a proportionality constant. In AM patients, our connectivity-based model predicted a significant decrease depression for sites near BA9, but not M1 for coil orientations perpendicular to the cortical gyrus. In control subjects, no site/orientation combination showed a significant predicted change. These results corroborate previous work suggesting the efficacy of left dlPFC stimulation for depression treatment, and predict better outcomes with individualized targeting. They also suggest that our novel connectivity-based e-field modelling approach may effectively identify potential TMS treatment responders and individualize TMS targeting to maximize the therapeutic impact.Subject terms: Cognitive control, Depression     

Preclinical development of novel anti-glioma drugs targeting the endoplasmic reticulum stress response

The endoplasmic reticulum (ER) stress response represents a cellular "yin-yang" process, where low to moderate activity is cell protective and supports chemoresistance (yang), but where more severe conditions will aggravate these mechanisms to the point where they abandon their protective efforts and instead turn on a cell death program (yin). Because tumor cells frequently experience chronic stress conditions (due to hypoxia, hypoglycemia, acidification, etc.), the protective yang components of their ER stress response are continuously engaged and thus less able to neutralize additional insults taxing the ER stress response. This tumor-specific situation may provide therapeutic opportunities for pharmacologic intervention, where further aggravation of ER stress would lead to the activation of pro-apoptotic yin components and result in tumor cell death. This review will describe the yin-yang principle of ER stress, and will present pharmacologic agents and combination strategies aimed at exploiting the ER stress response for improved therapeutic outcomes, particularly in the setting of difficult to treat tumor types such as glioblastoma.