Target-directed Approach Research Articles

Molecular Aspects and Therapeutic Implications of Herbal Compounds Targeting Different Types of Cancer.

Due to genetic changes in DNA (deoxyribonucleic acid) sequences, cancer continues to be the second most prevalent cause of death. The traditional target-directed approach, which is confronted with the importance of target function in healthy cells, is one of the most significant challenges in anticancer research. Another problem with cancer cells is that they experience various mutations, changes in gene duplication, and chromosomal abnormalities, all of which have a direct influence on the potency of anticancer drugs at different developmental stages. All of these factors combine to make cancer medication development difficult, with low clinical licensure success rates when compared to other therapy categories. The current review focuses on the pathophysiology and molecular aspects of common cancer types. Currently, the available chemotherapeutic drugs, also known as combination chemotherapy, are associated with numerous adverse effects, resulting in the search for herbal-based alternatives that attenuate resistance due to cancer therapy and exert chemo-protective actions. To provide new insights, this review updated the list of key compounds that may enhance the efficacy of cancer treatment.

Emerging Target-Directed Approaches for the Treatment and Diagnosis of Microbial Infections.

With the rising levels of drug resistance, developing efficient antimicrobial therapies has become a priority. A promising strategy is the conjugation of antibiotics with relevant moieties that can potentiate their activity by target-directing. The conjugation of siderophores with antibiotics allows them to act as Trojan horses by hijacking the microorganisms' highly developed iron transport systems and using them to carry the antibiotic into the cell. Through the analysis of relevant examples of the past decade, this Perspective aims to reveal the potential of siderophore-antibiotic Trojan horses for the treatment of infections and the role of siderophores in diagnostic techniques. Other conjugated molecules will be the subject of discussion, namely those involving vitamin B12, carbohydrates, and amino acids, as well as conjugated compounds targeting protein degradation and β-lactamase activated prodrugs.

Animal Models of Neurodegenerative Disease: Recent Advances in Fly Highlight Innovative Approaches to Drug Discovery.

Neurodegenerative diseases represent a formidable challenge to global health. As advances in other areas of medicine grant healthy living into later decades of life, aging diseases such as Alzheimer's disease (AD) and other neurodegenerative disorders can diminish the quality of these additional years, owed largely to the lack of efficacious treatments and the absence of durable cures. Alzheimer's disease prevalence is predicted to more than double in the next 30 years, affecting nearly 15 million Americans, with AD-associated costs exceeding $1 billion by 2050. Delaying onset of AD and other neurodegenerative diseases is critical to improving the quality of life for patients and reducing the burden of disease on caregivers and healthcare systems. Significant progress has been made to model disease pathogenesis and identify points of therapeutic intervention. While some researchers have contributed to our understanding of the proteins and pathways that drive biological dysfunction in disease using in vitro and in vivo models, others have provided mathematical, biophysical, and computational technologies to identify potential therapeutic compounds using in silico modeling. The most exciting phase of the drug discovery process is now: by applying a target-directed approach that leverages the strengths of multiple techniques and validates lead hits using Drosophila as an animal model of disease, we are on the fast-track to identifying novel therapeutics to restore health to those impacted by neurodegenerative disease.

Interface of Aging and Acute Peripheral Neuropathy Induced by Oxaliplatin in Mice: Target-Directed Approaches for Na+, K+-ATPase, Oxidative Stress, and 7-Chloro-4-(phenylselanyl) quinoline Therapy.

Almost 90% of patients develop pain immediately after oxaliplatin (OXA) treatment. Here, the impact of aging on OXA-induced acute peripheral neuropathy and the potential of 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) as a new therapeutic strategy were evaluated. In Swiss mice, the oxidative damage and its influence on Mg2+-ATPase and Na+, K+-ATPase activities were investigated. The relationship between the reactive oxygen species (ROS) and nitrate and nitrite (NOx) levels, the activity of glutathione peroxidase (GPx), and superoxide dismutase (SOD) with the development of OXA-induced acute peripheral neuropathy was also studied. In this study, it was evidenced that OXA-induced acute peripheral neuropathy was exacerbated by aging through increased oxidative damage as well as Na+, K+-ATPase, and Mg+2-ATPase inhibition. 4-PSQ reversed hypersensitivity induced by OXA and aging-aggravated by reducing ROS and NOx levels, through modulation of GPx and SOD activities. 4-PSQ partially reestablish Na+, K+-ATPase activity, but not Mg 2+-ATPase activity. Locomotor and exploratory activities were not affected. This study is the first of its kind, providing new insight into the aging impact on mechanisms involved in OXA-induced acute peripheral neuropathy. Also, it provides evidence on promising 4-PSQ effects on this condition, mainly on aging.

Thyroid Hormone and Neural Stem Cells: Repair Potential Following Brain and Spinal Cord Injury

Neurodegenerative diseases are characterized by chronic neuronal and/or glial cell loss, while traumatic injury is often accompanied by the acute loss of both. Multipotent neural stem cells (NSCs) in the adult mammalian brain spontaneously proliferate, forming neuronal and glial progenitors that migrate toward lesion sites upon injury. However, they fail to replace neurons and glial cells due to molecular inhibition and the lack of pro-regenerative cues. A major challenge in regenerative biology therefore is to unveil signaling pathways that could override molecular brakes and boost endogenous repair. In physiological conditions, thyroid hormone (TH) acts on NSC commitment in the subventricular zone, and the subgranular zone, the two largest NSC niches in mammals, including humans. Here, we discuss whether TH could have beneficial actions in various pathological contexts too, by evaluating recent data obtained in mammalian models of multiple sclerosis (MS; loss of oligodendroglial cells), Alzheimer’s disease (loss of neuronal cells), stroke and spinal cord injury (neuroglial cell loss). So far, TH has shown promising effects as a stimulator of remyelination in MS models, while its role in NSC-mediated repair in other diseases remains elusive. Disentangling the spatiotemporal aspects of the injury-driven repair response as well as the molecular and cellular mechanisms by which TH acts, could unveil new ways to further exploit its pro-regenerative potential, while TH (ant)agonists with cell type-specific action could provide safer and more target-directed approaches that translate easier to clinical settings.

Target-Directed Approaches for Screening Small Molecules against RNA Targets.

RNA molecules have a variety of cellular functions that can drive disease pathologies. They are without a doubt one of the most intriguing yet controversial small-molecule drug targets. The ability to widely target RNA with small molecules could be revolutionary, once the right tools, assays, and targets are selected, thereby defining which biomolecules are targetable and what constitutes drug-like small molecules. Indeed, approaches developed over the past 5-10 years have changed the face of small molecule-RNA targeting by addressing historic concerns regarding affinity, selectivity, and structural dynamics. Presently, selective RNA-protein complex stabilizing drugs such as branaplam and risdiplam are in clinical trials for the modulation of SMN2 splicing, compounds identified from phenotypic screens with serendipitous outcomes. Fully developing RNA as a druggable target will require a target engagement-driven approach, and evolving chemical collections will be important for the industrial development of this class of target. In this review we discuss target-directed approaches that can be used to identify RNA-binding compounds and the chemical knowledge we have today of small-molecule RNA binders.

Readmission Rates and Associated Outcomes for Alcoholic Hepatitis: A Nationwide Cohort Study.

Alcoholic hepatitis (AH) can lead to sudden and severe hepatic decompensation necessitating recurrent hospitalizations. We evaluated the trends, predictors, and healthcare cost burden of AH-related readmissions in the USA. Utilizing the National Readmissions Database 2010-2014, we performed a retrospective longitudinal analysis to identify the index readmission with AH for up to 90days after discharge. Annual trends of 30- and 90-day AH-related readmissions were calculated. Predictors of 30- and 90-day readmission were determined by multivariate logistic regression. Annual healthcare cost burden associated with AH-linked readmissions was estimated. Of the 21,572 (unweighted: 50,769) AH-related hospitalizations, 4917 (22.8%) and 7890 (36.6%) were readmitted in 30 and 90day, respectively, with rates that were statistically unchanged from 2010 to 2014. Predictors of 30-day readmissions included female gender, hepatitis C virus infection, cirrhosis, ascites, acute kidney injury, urinary tract infection, history of bariatric surgery, chronic pancreatitis, and high medical comorbidity index. Acute pancreatitis and palliative care consultation were associated with a lower risk of 30-day readmission. Predictors of 90-day readmission were similar to risk factors for 30-day readmission. From 2010 to 2014, the annual cost (and total hospitalization days) burden increased in 2014 to $164 million (22,244days) and $321 million (42,772days) for 30- and 90-day AH-related readmissions, respectively. Despite relatively stable trends in AH-related readmission, the total LOS and cost has been rising. A target-directed approach with a focus on high-risk subpopulations may help understand the unique challenges associated with the rising cost of AH-related readmissions.

Looking Inside the Matrix: Perineuronal Nets in Plasticity, Maladaptive Plasticity and Neurological Disorders.

The integrity of the central nervous system (CNS) matrix is crucial for its proper function. Loss of the lattice-like structure compromise synaptic stability and can lead to the disruption of the excitatory/inhibitory balance, astrocytosis, maladaptive plasticity and neuronal death. Perineuronal nets (PNNs) in the extracellular matrix (ECM) provide synaptic integration and control the functional wiring between neurons. These nets are significantly modified during CNS disorders, such as neurodegenerative, cerebrovascular and inflammatory diseases. The breakdown or the modification of PNNs could be due to the activity of matrix metalloproteinases (MMPs) or to the deposition of proteoglycans, glycoproteins, and hyaluronic acid. The expression and the activity of ECM-degrading enzymes can be regulated with tissue inhibitors of MMPs or via transcriptional and epigenetic silencing or enhancement (i.e. via histone deacetylases). The identification of molecules and mechanisms able to modify these processes will be essential for a new perspective on brain functioning in health and disease, leading to a target-directed approach with drugs directly interfering with the molecular mechanism underlying neurological disorders.

AB1403 Comprehensive target-directed approach for the development of a highly-comparable rituximab biosimilar

BackgroundBiosimilars are successor drug products to a biologic medicine that is already authorized and whose patent is no longer valid. As with their originator products, biosimilars are expressed using living...

Treating breast cancer in the 21st century: emerging biological therapies.

For many years, the medical treatment of breast cancer was reliant solely on cytotoxic chemotherapy. However, over the past twenty years, treatment has evolved to a more target-directed approach. We now employ tailored therapy based on the presence or absence of receptors for estrogen, progesterone, and human epidermal growth factor 2 (HER2). We expect this trend to continue, as agents that use novel approaches to target HER2, as well as targeting different portions of the HER signaling pathway, are in various stages of development. Notably, pertuzumab, a humanized monoclonal antibody that binds to a different domain of the extracellular portion of the HER2 receptor than trastuzumab, was recently approved for use, as was lapatinib, a small-molecule tyrosine kinase inhibitor. Patients with triple negative breast cancer, particularly those with the BRCA mutation, have more limited treatment options and carry a worse prognosis than those who are hormone receptor positive. However, recent data has shown that PARP inhibitors may have significant anti-tumor effect in those with this subtype of breast cancer. Novel agents that inhibit mTOR, PI3K, the insulin-like growth factor, heat shock protein 90, and histone deacetylase have shown promise in phase I-III trials and offer exciting new possibilities for the treatment of this often fatal disease. As we are presented with an ever increasing number of treatment options, the timing and combinations of therapeutic agents used becomes ever more complex in the age of personalized care, but we are hopeful that ultimately this will lead to improved patient outcomes.

Challenges and Opportunities in the Development of Protein Phosphatase-Directed Therapeutics

Protein phosphatases have both protective and promoting roles in the etiology of diseases. A prominent example is the existence of oncogenic as well as tumor-suppressing protein phosphatases. A few protein phosphatase activity modulators are already applied in therapies. These were however not developed in target-directed approaches, and the recent discovery of phosphatase involvement followed their application in therapy. Nevertheless, these examples demonstrate that small molecules can be generated that modulate the activity of protein phosphatases and are beneficial for the treatment of protein phosphorylation diseases. We describe here strategies for the development of activators and inhibitors of protein phosphatases and clarify some long-standing misconceptions concerning the druggability of these enzymes. Recent developments suggest that it is feasible to design potent and selective protein phosphatase modulators with a therapeutic potential.

Molecular targeting in the treatment of either advanced or metastatic bladder cancer or both according to the signalling pathways

An estimated 300,000 new cases of bladder cancer worldwide are diagnosed annually. Although new cytotoxic chemotherapeutic agents for either advanced or metastatic bladder cancer or both are used, no improvement in survival has been observed. Indeed, the 5-year survival rate of metastatic bladder cancer is very low (6%). The target-directed approach is an attractive challenge for treating specific genetic alterations involved in progression and metastasis development. This article aims to describe the new targeted therapies available to cure advanced cancer or metastatic bladder cancer or both according to the signalling pathways potentially involved. The rapidly expanding understanding of the pathogenesis of bladder cancer at the molecular level has led to the identification of signalling pathways involved in this disease and provided molecular targets for new biological agents directed against tumorigenesis and progression. The recent results of clinical trials have not only highlighted the need to select patients who could benefit from such a therapy but also the fact that oncology has completely entered into a new era. Toxic chemotherapeutic agents are slowly being supplemented by a new generation of drugs that recognize specific targets in or on cancer cells. Recent technological advances in pharmacogenomics and proteomics have led to an improvement in identifying biomarkers predictive of response and thereby to identify patients who would be more likely to respond to such a therapy. There is a real hope to improve both the efficiency and the tolerability of bladder cancer treatment.

Future Prospects for Old Chemotherapeutic Drugs in the Target-Specific Era; Pharmaceutics, Combinations, Co-Drugs and Prodrugs with Melphalan as an Example

During the last decade, resulting from expanded knowledge in tumor biology, several new and target-specific approaches have been presented. With some exceptions, however, most early clinical trials with these compounds are discouraging, suggesting that the expanding knowledge might not easily translate into new substantially better anti-cancer drugs. One of the classical chemotherapeutic agents is melphalan, first synthesized over fifty years ago. The anti-tumor effect has been attributed to alkylation of cellular nucleophiles, among them DNA. Intravenous melphalan has single-agent activity in a variety of solid tumors and has good activity alone or combined with other drugs or radiation in high-dose bone marrow transplant regimens for breast cancer, ovarian cancer, testicular cancer and multiple myeloma. Recent studies suggest a continuous role for melphalan as part of high dose combination therapy in advanced solid tumor malignancies. Immediately after the first publication on melphalan (p-L-bis(2-chloroethyl)aminophenylalanine), investigators began attempting to improve the therapeutic index and thus provide a greater margin of clinical safety during treatment with the drug. The amino-acid based chemical structure of melphalan invites to modification of both the N- and C-termini as well as incorporation into peptides. In this review we discuss the past and present history of melphalan in the perspective of modern cancer chemotherapy, from the medicinal chemists point of view, and with special emphasis on how target-directed approaches have been applied to the molecule. Keywords: Melphalan, Prodrugs, Chemotherapeutics, Cancer target