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At least 505 records · Page 28Linked to original sources

Direct-tissue SELDI-TOF mass spectrometry analysis: a new application for clinical proteomics.

BACKGROUND: New molecular profiling technologies can aid in analysis of small pathologic samples obtained by minimally invasive biopsy and may enable the discovery of key biomarkers synergistic with anatomopathologic analysis related to prognosis, therapeutic response, and innovative target validation. Thus proteomic analysis at the histologic level in healthy and pathologic settings is a major issue in the field of clinical proteomics. METHODS: We used surface-enhanced laser desorption ionization-time-of-flight mass spectrometry (SELDI-TOF MS) technology with surface chromatographic subproteome enrichment and preservation of the spatial distribution of proteomic patterns to detect discrete modifications of protein expression. We performed in situ proteomic profiling of mouse tissue and samples of human cancer tissue, including brain and lung cancer. RESULTS: This approach permitted the discrimination of glioblastomas from oligodendrogliomas and led to the identification of 3 potential markers. CONCLUSION: Direct tissue proteomic analysis is an original application of SELDI-TOF MS technology that can expand the use of clinical proteomics as a complement to the anatomopathological diagnosis.

Animals↗

Gene-array analysis of glioma cells after treatment with an anti-PKCalpha siRNA: a general protocol.

Post-transcriptional gene silencing is a powerful tool to reveal gene function. In this chapter, we have used gene-array technology to analyze changes in gene expression after specific targeting of the protein kinase Calpha isoform with small interfering RNAs (siRNAs). Expression profiles were investigated on a human gene array of 588 key genes involved in DNA synthesis, apoptosis, cell-cell communication, intracellular signal-transduction pathways, cell-surface molecules and transcription factors. The data indicate that siRNAs are an ideal tool for target validation, and show that RNA-dependent RNA polymerase is not required for RNAi in mammalian cells.

Cell Line, Tumor↗

Production of siRNA- and cDNA-transfected cell arrays on noncoated chambered coverglass for high-content screening microscopy in living cells.

In this chapter, we provide a protocol for the production of transfected cell arrays in living mammalian cells on noncoated chambered coverglass for the systematic functional analyses of human genes by high-content screening microscopy. This method should facilitate drug target validation by small-interfering RNAs.

Image Processing, Computer-Assisted↗

Discovery of protein kinase phosphatase inhibitors.

Dynamic protein phosphorylation, a major cellular regulatory system, is tightly controlled by coordinating the reversible action of protein kinases and phosphatases. Recent evidence is consistent with sophisticated mechanisms that regulate both kinases and phosphatases in the cell. Dual specificity phosphatases, which act on phosphorylated serine, threonine, and tyrosine residues in proteins, are valid targets for drug discovery. Chemical complementation combines genetic manipulations with chemical biology and high-content multiparametric analyses and was developed as a screening approach to discover protein phosphatase inhibitors. Using a dual specificity mitogen-activated protein kinase phosphatase as an example, a detailed protocol, discussion of issues relating to data analysis, and high-throughput implementation of the chemical complementation approach to drug discovery is presented.

Cell Cycle Proteins↗

ADAM proteases, ErbB pathways and cancer.

A disintegrin and metalloproteases (ADAMs) are zinc-dependent trans-membrane metalloproteases that shed the extracellular domains of membrane-bound growth factors, cytokines and receptors. Key functions of ADAMs have emerged in ErbB signalling pathways as being sheddases for multiple ErbB ligands. As the ErbB pathway is a validated target for anti-cancer drugs, the upstream activators of ErbB ligands, their sheddases, now enter the spotlight as new drug targets in the ErbB pathway. ADAMs are involved not only in tumour cell proliferation but also in angiogenesis and metastasis. Therefore, strategies targeting ADAMs might be an important complement to existing anti-ErbB approaches.

ADAM Proteins↗

Small molecule antagonists of alpha4 integrins: novel drugs for asthma.

The alpha4 integrins, alpha4beta1 (VLA-4) and alpha4beta7, are heterodimeric cell-surface proteins expressed on leukocytes involved in both cell-cell and cell-matrix interactions. These two integrins are key regulators of physiologic and pathologic responses in inflammation and autoimmune disease. In particular, their central role in animal models of allergic lung disease has been well documented, and suggests a key role in human asthma. In addition, integrins are proven valid targets for small molecule drugs, following the development of both parenteral and orally active antagonists of platelet integrin alphaIIbbeta3, and more recently, integrin alphaVbeta3. Therefore, there is a significant drive to develop small molecule inhibitors of alpha4 integrins for autoimmune diseases in general, and asthma in particular. The biology of alpha4 integrins in asthma has been recently reviewed, as has early work on the chemistry of alpha4 integrin antagonists. Here we summarise the recent rapid advances in this arena, particularly in the chemistry of alpha4 integrin small molecule antagonists, with emphasis on asthma as a clinical target.

Journal Article↗

Immunologic approaches to antigen discovery for cancer vaccines.

Since the early 1990s, scientists have identified an ever-expanding number of antigens to serve as targets for experimental cancer treatments, based on the stimulation of a patient's immune system. Using both immune cells and serum to screen potential candidates, several promising antigens are currently components of vaccines directed against a wide range of tumour types. These antigens vary in their tumour- and tissue-specificity. Their utility as a single reagent or as part of a multi-dimensional approach is as varied as the genes themselves. However, there are already reports indicating that the promise of evoking a clinically beneficial immune response, toward human tumours, is being fulfilled. In this review, we provide a summary of the current status of immunologic approaches to antigen discovery. We also discuss the need for additional, supportive data from non-immunologic techniques, as well as the progression of the preclinical process towards target validation.

Antigens↗

Affymetrix, Inc.

Affymetrix creates breakthrough tools for applications in the drug development process and pharmacogenomics. By applying the principles of semiconductor technology to the life sciences, Affymetrix has created the GeneChipmicroarray platform for both gene expression analysis (mRNA) and genetic analysis (DNA). The company's integrated system is setting the standard for basic research and target identification and is now being adopted in additional research applications, such as target validation and toxicogenomics, as well as in healthcare applications including clinical trials and health management. Affymetrix' current customers include pharmaceutical, biotechnology, agrochemical, diagnostic and consumer product companies as well as academic, government and other non-profit research institutions. Additional information on Affymetrix can be found at www.affymetrix.com.

Humans↗

RASONs: a novel antisense oligonucleotide therapeutic approach for asthma.

Inhalation based approaches enable the local delivery of antisense oligonucleotides (ASONs) to the respiratory tract and thus facilitate the ability of ASONs to target and modulate the activity of discordantly expressed respiratory disease genes. Studies involving EPI-2010, a respirable antisense oligonucleotide (RASON), targeting the adenosine A(1) receptor, a G-protein-coupled-receptor (GPCR) that plays an important role in the aetiology of asthma, demonstrate that ASON therapeutics can be delivered directly to the lung as an aerosol. EPI-2010 has been shown to inhibit adenosine A(1) receptor expression and significantly improve allergen-induced airway obstruction and bronchial hyper-responsiveness in animal models of human asthma. Absorption, tissue distribution, metabolism and excretion (ADME) and safety studies of aerosolised EPI-2010 suggest that phosphorothioate RASONs can be delivered to target respiratory tissues in low, safe, efficacious and long-acting doses. This supports the concept that RASONs offer the potential to address a variety of respiratory targets including those for which approaches employing systemic distribution and systemic bioavailability of the therapeutic agent may be undesirable. In addition, our studies with EPI-2010 indicate that the RASON approach may represent a technology that is uniquely positioned to address the challenges of the post-genome era in respiratory drug discovery, since it enables simultaneous in vivo target validation and antisense therapeutic discovery in an accelerated timeframe.

Adenosine↗

10th International Conference on gene therapy of cancer: 13 - 15 December 2001, San Diego, CA, USA.

This annual meeting was organised by R Sobol and A Deisseroth (Sidney Kimmel Cancer Center, San Diego, CA, USA) and K Scanlon (Keck Graduate Institute, Claremont, CA, USA). The meeting covered a wide range of topics in cancer gene therapy and included five sessions. The topics were: (1) Tumour suppressors/apoptosis/antisense-ribozymes/angiogenesis; (2) Vector systems; (3) Therapy sensitisation/'suicide' gene therapy; (4) Haematopoietic gene transfer; and (5) Poster/discussion sessions. The following meeting highlights have focused mainly on the recent progress in antisense/ribozyme-based approaches useful for cancer gene target validation and drug development.

DNA, Single-Stranded↗

A novel single-stranded DNA expression vector.

A novel expression vector system has been developed that can intracellularly generate any single-stranded DNA (ssDNA) molecule, such as a triplex-forming oligonucleotide (TFO), antisense oligodeoxynucleotide (ODN) and DNA enzyme, by our laboratory at CytoGenix, Inc. 'Proof of concept' studies from our laboratory as well as our collaborators' indicate that this ssDNA expression vector system is capable of producing, intracellularly, antisense ODNs, DNA enzymes or TFOs for the purpose of downregulating gene expression or inducing targeted genome modification. This technology provides new research tools and has potential applications in gene target validation and drug development.

Animals↗

siRNA as a route to new cancer therapies.

The RNA interference (RNAi) gene-silencing mechanism is induced by double-stranded RNA (dsRNA) and is highly sequence-specific. It is an extremely powerful tool for silencing gene expression in vitro, and might be used as therapy in human pathologies such as cancer, viral infections and genetic disorders. RNAi was initially discovered in plants, but it has become clear that it is also conserved in animal species. Triggering of RNAi by the introduction of small dsRNA (or small interfering RNA) into living cells as a tool to inhibit the expression of specific genes holds the promise to selectively extinguish the expression of disease-associated genes in humans. On the other hand, RNAi technology will serve to elucidate the functions and interactions of the thousands of human genes in high-throughput systems and help in target validation technology.

Animals↗

Chemical genetic analysis of signal transduction pathways.

Covalent modification of proteins by phosphorylation represents a major mechanism of signal transduction that contributes to many physiological and pathophysiological processes. The enzymes that regulate protein phosphorylation (e.g., protein kinases and phosphatases) are, therefore, potential targets for the rational design of small-molecule drugs for the treatment of many diseases. A critical aspect of drug design is the reliability of proof-of-principle studies that demonstrate the therapeutic potential of the drug target. Studies using genetically modified mouse models that lack expression of the drug target using gene ablation and RNAi-based technologies have been widely employed. Recently, an alternative strategy using a chemical genetic approach has been proposed. Here, the authors discuss the strengths and weaknesses of the chemical genetic approach for studies of target validation.

Drug Design↗

The potential of antisense as a CNS therapeutic.

Antisense offers a precise and specific means of knocking down expression of a target gene, and is a major focus of research in neuroscience and other areas. It has application as a tool in gene function and target validation studies and is emerging as a therapeutic technology in its own right. It has become increasingly obvious, however, that there are a number of hurdles to overcome before antisense can be used effectively in the CNS, most notably finding suitable nucleic acid chemistries and an effective delivery vehicle to transport antisense oligonucleotides (AS-ODNs) across the blood-brain barrier (BBB) to their site of action. Despite these problems, a number of potential applications of AS-ODNs in CNS therapeutics have been validated in vitro and, in some cases, in vivo. Here the authors outline available nucleic acid chemistries and review progress in the development of non-invasive delivery vehicles that may be applicable to CNS therapeutics. Further to this, they discuss a number of experimental applications of AS-ODNs to CNS research and speculate on the development of antisense techniques to treat CNS disease.

Alzheimer Disease↗

TNF and congestive heart failure: therapeutic possibilities.

TNF-alpha is a cytokine that may play a role in the pathogenesis of heart failure. In patients with heart failure, increased levels of TNF-alpha were observed that were high enough to reduce cardiac contractility in vitro. The mortality of heart failure patients increases with higher levels of TNF-alpha. For these reasons, inhibition of TNF-alpha appears to be a valid target for the improvement of heart failure therapy beyond the current practice of inhibiting neurohormonal activation with beta-blockade, angiotensin-converting enzyme (ACE) inhibition and aldosterone antagonism. However, whilst this strategy (using soluble TNF receptor or TNF antibodies) was successful in smaller short-term studies, larger longer-term studies have not revealed any beneficial effect of this therapy (RENAISSANCE, RECOVER, RENEWAL, ATTACH). In contrast, the mortality tended to be higher in the treated groups giving rise to questions about the overall strategy. The reasons for this failure of the clinical studies to show a longer-term benefit from TNF-alpha inhibitors are unclear, but they may include an error of the general concept, individual adverse effects of the agents used for the studies, incorrect dosage and the fact that the current therapy of heart failure with beta-blockade, ACE inhibitors and aldosterone antagonists cannot be further improved by additional blockade of neurohormones or cytokines.

Animals↗

New targets for neuropathic pain therapeutics.

Neuropathic pain (NeP) is initiated by a lesion or dysfunction in the nervous system. Unlike physiological pain it serves no useful purpose and is usually sustained and chronic. NeP encompasses a wide range of pain syndromes of diverse aetiologies which together account for > 12 million sufferers in the US. Currently, there are a number of therapies available for NeP, including gabapentin, pregabalin, anticonvulsants (tiagabine HCl), tricyclic antidepressants (amitriptyline, nortriptyline) and acetaminophen/opioid combination products (Vicodin, Tylenol #3). However, these products do not provide sufficient pain relief and a significant proportion of sufferers are refractory (60%). Therefore, there is a need for new therapies that provide more predictable efficacy in all patients with improved tolerability. Over the last decade, understanding of the basic mechanisms contributing to the generation of NeP in preclinical animal models has greatly improved. Together with the completion of the various genome sequencing projects and significant advances in microarray and target validation strategies, new therapeutic approaches are being rigourously pursued. This article reviews the rationale behind a number of these mechanism-based approaches, briefly discusses specific challenges that they face, and finally, speculates on the potential of emerging technologies as alternative therapeutic strategies to the traditional 'small-molecule' approach.

Analgesics↗

Antibody-based therapeutics in oncology.

The recent clinical and commercial success of anticancer antibodies, such as rituximab (Rituxan) and trastuzumab (Herceptin) has created great interest in antibody-based therapeutics for hematopoietic malignancies and solid tumors. Given the likely lower toxicity for antibodies versus small molecules, the potential increase in efficacy by conjugation to radioisotopes and other cellular toxins and the ability to characterize the target with clinical laboratory diagnostics to improve the drug's clinical performance, it is anticipated that current and future antibody therapeutics will find substantial roles alone and in combination therapy strategies for the treatment of patients with cancer. It is also likely that conjugation strategies will add new radiolabeled and toxin-linked products to the market to complement the recent approvals of ibritumomab tiuxetan (Zevalin) and gemtuzumab ozogamycin (Mylotarg). However, although there are a large number of agents in both early and later stages of clinical development, only a handful will make it through regulatory approval and become successful products. This review considers the structure of anticancer therapeutic antibodies, the techniques used to reduce their antigenicity, factors that influence efficacy and toxicity, conjugation with isotopes and toxins and antibody target validation.

Antibodies, Monoclonal↗

DNA array technology and diagnostic microbiology.

Near instantaneous detection of pathogens from clinical material, combined with simultaneous prediction of their antimicrobial resistance profiles, would revolutionize the impact of microbiology on the management of infection. Array-based assays allow a range of characteristics to be rapidly and simultaneously determined. At present these systems have found their primary role as research tools for the monitoring of mRNA expression in the form of DNA microarrays or 'chips'. As fabrication costs reduce and validated targeted arrays are developed, it is inevitable they will be used for more routine applications. Microfluidics offers the exciting possibility of combining purification, amplification and detection in a single disposable device; microarrays are particularly suitable for use within these systems. Arrays will become an important tool for clinical diagnostics.

Animals↗