Leopard Syndrome

Allosteric Inhibitors of SHP2: An Updated Patent Review (2015-2020)

Srchomology-2-domain-containing PTP 2 (SHP2) is a nonreceptor phosphatase encoded by the PTPN11 gene. Over expression of SHP2 is associated with various human diseases, such as Noonan syndrome, LEOPARD syndrome, and cancers. To overcome the shortcomings of existing orthosteric inhibitors, novel inhibitors targeting the allosteric site of SHP2 with high selectivity and low toxicity are under development. This paper reviews allosteric inhibitors of SHP2 published in patents from 2015 to 2020. The molecules are classified according to the chemical structure of the central core. SHP2 has long been considered as an ‘undruggable’ protein. Fortunately, a critical breakthrough was made by researchers from Novartis AG Ltd., who identified SHP099 as a highly potent, selective, soluble, and orally bioavailable SHP2 allosteric inhibitor. Currently, there are several allosteric inhibitors of SHP2 in clinical development. However, drug resistance is still a major challenge. The combination of SHP2 allosteric inhibitors and immunotherapy drugs or molecular targeted drugs is emerging as a promising therapeutic strategy against drug resistance.

Inhibitor Binding Sites in the Protein Tyrosine Phosphatase SHP-2

Protein tyrosine phosphatase 2 (SHP-2) has long been proposed as a cancer drug target. Several small-molecule compounds with different mechanisms of SHP-2 inhibition have been reported, but none are commercially available. Pool selectivity over protein tyrosine phosphatase 1 (SHP-1) and a lack of cellular activity have hindered the development of selective SHP-2 inhibitors. In this review, we describe the binding modes of existing inhibitors and SHP-2 binding sites, summarize the characteristics of the sites involved in selectivity, and identify the suitable groups for interaction with the binding sites.

Induced Pluripotent Stem Cell Technology: A Paradigm Shift in Medical Science for Drug Screening and Disease Modeling

Background: Induced Pluripotent Stem Cell (IPSC) Technology is the most advanced research as it offers an attractive alternative for establishing patient-specific IPSCs to recapitulate phenotypes of not only monogenic diseases (viz. Thalassaemia, Sickle cell anemia, Haemophilia, Tay-Sachs disease), but also late-onset polygenic diseases (viz. Parkinson's disease, Alzheimer's disease, schizophrenia). Over the hindsight, numerous studies of the past and current scientists have led to the production, maturation and understanding of induced pluripotent stem cell technology and its use in basic and clinical research.

Methods: A systematic search of peer-reviewed scientific literature and clinical trials in public databases were carried out to summarize the evidence on the use of IPSC.

Results: Current review sheds light upon the use of patient-derived iPSC models in drug toxicity, screening and discovery which have been derived after referring to more than 200 articles in literature. Furthermore, their use as disease models was also studied signifying the versatility of iPSC lines.

Conclusion: Through this review, we describe the advent of iPSC technology, where we comprehensively cover the generation of iPSCs and their characterization along with their prospective applications using IPSC banks in disease modeling and drug screening.

Protein Tyrosine Signaling and its Potential Therapeutic Implications in Carcinogenesis

Protein tyrosine phosphorylation is a crucial signaling mechanism that plays a role in epithelial carcinogenesis. Protein tyrosine kinases (PTKs) control various cellular processes including growth, differentiation, metabolism, and motility by activating major signaling pathways including STAT3, AKT, and MAPK. Genetic mutation of PTKs and/or prolonged activation of PTKs and their downstream pathways can lead to the development of epithelial cancer. Therefore, PTKs became an attractive target for cancer prevention. PTK inhibitors are continuously being developed, and they are currently used for the treatment of cancers that show a high expression of PTKs. Protein tyrosine phosphatases (PTPs), the homeostatic counterpart of PTKs, negatively regulate the rate and duration of phosphotyrosine signaling. PTPs initially were considered to be only housekeeping enzymes with low specificity. However, recent studies have demonstrated that PTPs can function as either tumor suppressors or tumor promoters, depending on their target substrates. Together, both PTK and PTP signal transduction pathways are potential therapeutic targets for cancer prevention and treatment.

Protein Tyrosine Phosphatase SHP-2 as Drug Target

Protein tyrosine kinase (PTK) and tyrosine phosphatase (PTP) regulate various cellular processes. SHP-2, a ubiquitous non receptor type protein belongs to tyrosine phosphatase family. SHP-2 consists of two SH2 domain (N-SH2 and C-SH2), one C-terminal tail and a phosphatase domains. SHP2 is involved in regulating JAK-STAT and MAPK signaling pathways required for cell growth and differentiation. In the inactive form, SHP-2 is available in the closed conformation and gets activated after phosphorylation of tyrosine residues. SHP-2 protein is encoded with PTPN11 gene. Germline mutation in PTPN11 gene causes disruption in its closed conformation and causes over-expression of SHP-2 phosphatase activity. Deregulation of phosphatase activity leads to pathogenesis of cancer and diseases like Noonan and Leopard syndrome. Thus, SHP-2 inhibitors have been developed as a novel target for treating cancer and diseases caused due to abnormal cellular signaling. This review is a description of role of SHP-2 in cell physiology, diseases caused due to SHP-2 deregulation along with some SHP-2 inhibitors.

Human Induced Pluripotent Stem Cells for Inherited Cardiovascular Diseases Modeling

Cardiovascular cells derived from patient specific induced Pluripotent Stem Cell (iPSC) harbor gene mutations associated with the pathogenesis of inherited cardiac diseases and congenital heart diseases (CHD). Numerous reports have demonstrated the utilization of human induced Pluripotent Stem Cell (hiPSC) to model cardiac diseases as a means of investigating their underlying mechanisms. So far, they have been shown to investigate the molecular mechanisms of many cardiac disorders, such as long-QT syndrome (LQT), catecholaminergic polymorphic ventricular tachycardia (CPVT), dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), LEOPARD syndrome (LS), arrhythmogenic cardiomyopathy (ACM), Friedreich ataxia (FRDA), Barth syndrome (BTHS), hypoplastic left heart syndrome (HLHS), Marfan syndrome (MFS) and other CHD. This article summarizes the growing body of research related to modeling various cardiac diseases using hiPSCs. Moreover, by reviewing the methods used in previous studies, we propose multiple novel applications of hiPSCs to investigate comprehensive cardiovascular disorders and facilitate drug discovery.

Contextualizing the Genes Altered in Bladder Neoplasms in Pediatric and Teen Patients Allows Identifying Two Main Classes of Biological Processes Involved and New Potential Therapeutic Targets

Research on bladder neoplasms in pediatric and teen patients (BNPTP) has described 21 genes, which are variously involved in this disease and are mostly responsible for deregulated cell proliferation. However, due to the limited number of publications on this subject, it is still unclear what type of relationships there are among these genes and which are the chances that, while having different molecular functions, they i) act as downstream effector genes of well-known pro- or anti- proliferative stimuli and/or interplay with biochemical pathways having oncological relevance or ii) are specific and, possibly, early biomarkers of these pathologies. A Gene Ontology (GO)-based analysis showed that these 21 genes are involved in biological processes, which can be split into two main classes: cell regulation-based and differentiation/development-based. In order to understand the involvement/ overlapping with main cancer-related pathways, we performed a meta-analysis dependent on the 189 oncogenic signatures of the Molecular Signatures Database (OSMSD) curated by the Broad Institute. We generated a binary matrix with 53 gene signatures having at least one hit; this analysis i) suggests that some genes of the original list show inconsistencies and might need to be experimentally re- assessed or evaluated as biomarkers (in particular, ACTA2) and ii) allows hypothesizing that important (proto)oncogenes (E2F3, ERBB2/HER2, CCND1, WNT1, and YAP1) and (putative) tumor suppressors (BRCA1, RBBP8/CTIP, and RB1-RBL2/p130) may participate in the onset of this disease or worsen the observed phenotype, thus expanding the list of possible molecular targets for the treatment of BNPTP.

Crosstalk Between Bioactive Peptide and Intestinal Barrier in Gut Homeostasis

The bioactive peptides are protein fragments which have a positive impact on the intestinal homeostasis. Intestinal homeostasis depends on the diverse functions of intestinal barrier including the microbiological, physical, chemical and immunological barriers. Defects in intestinal barrier function are associated with intestinal diseases. In this review, we will present current knowledge of the crosstalk between bioactive peptides and intestinal barrier during gut homeostasis.

Multitarget Network Strategies to Influence Memory and Forgetting: The Ras/Mapk Pathway as a Novel Option

The Ras/mitogen activated protein kinase (MAPK) pathway has key importance in development, cell differentiation and senescence, tumorigenesis, learning and memory. The clinical manifestations associated with this highly conserved pathway are called RASopathies. Phenotypic features are diverse and overlapping, but cognitive impairment is a common symptom. Here, we propose an approach based on molecular networks that link learning, memory and forgetting to the RASopathies and various neurodegenerative and neurodevelopmental diseases such as Alzheimer's disease, Parkinson's disease and autism spectrum disorders. We demonstrate the cross-talks of the molecular pathways in RASopathies and memory and the role of compartmentalization in these processes. The approved drugs are also overviewed, and C. elegans is proposed as a viable model system for experimental exploration and compound target prediction.n

Cathinone Neurotoxicity (“The “3Ms”)

Synthetic cathinones are designer drugs of the phenethylamine class, structurally and pharmacologically similar to amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), cathinone and other related substances. New analogues, legal at least, until formally banned (a time consuming process), are introduced almost daily The United Nations estimates nearly 250 new drug analogues are produced per year. Various combinations of these drugs are sold under the name of “bath salts.” They can be ingested by any route and some appear capable of causing great harm, mostly behavioral. One drug in particular, MDVP, appears to frequently cause symptoms indistinguishable from the classic findings in Excited Delirium Syndrome (ExDS). Little is known about the pathology or clinical toxicology of these drugs but their molecular mechanism of action seems to be identical with that of cocaine. This mini-review examines what little is known on the subject and explains the suspected mechanisms of excited delirium syndrome.

Tetralogy of Fallot and Hypoplastic Left Heart Syndrome – Complex Clinical Phenotypes Meet Complex Genetic Networks

In many cases congenital heart disease (CHD) is represented by a complex phenotype and an array of several functional and morphological cardiac disorders. These malformations will be briefly summarized in the first part focusing on two severe CHD phenotypes, hypoplastic left heart syndrome (HLHS) and tetralogy of Fallot (TOF). In most cases of CHD the genetic origin remains largely unknown, though the complexity of the clinical picture strongly argues against a dysregulation which can be attributed to a single candidate gene but rather suggests a multifaceted polygenetic origin with elaborate interactions. Consistent with this idea, genome-wide approaches using whole exome sequencing, comparative sequence analysis of multiplex families to identify de novo mutations and global technologies to identify single nucleotide polymorphisms, copy number variants, dysregulation of the transcriptome and epigenetic variations have been conducted to obtain information about genetic alterations and potential predispositions possibly linked to the occurrence of a CHD phenotype. In the second part of this review we will summarize and discuss the available literature on identified genetic alterations linked to TOF and HLHS.

Genetics of Cardiomyopathies: Novel Perspectives with Next Generation Sequencing

Cardiomyopathies are a heterogeneous group of primary diseases of the myocardium usually of genetic origin and with familial presentation. The identification of multiple genetic causes for these diseases has opened a new window for early diagnosis, understanding of their natural history and improvement in risk stratification and management. However, in the past years, the clinical application of genetics has been limited by the prohibiting cost and restricted yield of the available genotyping technologies. The emergence of Next Generation Sequencing (NGS) has completely changed this scenario. This group of sequencing technologies allow the evaluation of hundreds or even thousands of genes in parallel at an affordable cost. Now the challenge is not genotyping per se but the interpretation of the complex results that NGS generates. In this paper we review the main aspects related to the application and impact of Next Generation Sequencing in the study of cardiomyopathies: technology, analysis procedures, bioinformatics, clinical validation and interpretation of results.

Beta-Blockers in Pediatric Hypertrophic Cardiomyopathies

Congestive cardiac failure accounts for 36% of childhood deaths in hypertrophic cardiomyopathy, and in infants with heart failure symptoms before two years of age, the mortality is extremely high unless treatment with betareceptor antagonists is instituted. The mechanism of heart failure is not systolic dysfunction, but rather extreme diastolic dysfunction leading to high filling pressures.

Risk factors for development of heart failure are a generalized pattern of hypertrophy with a left ventricular posterior wallto- cavity ratio >0.30, the presence of left ventricular outflow tract obstruction at rest, and the co-existence of syndromes in the Noonan/Leopard/Costello spectrum. The 5-year survival of high-risk patients is improved from 54% to 93% by highdose beta-blocker therapy (>4.5 mg/kg/day propranolol). The mechanism of the beneficial effect of beta-blockers is to improve diastolic function by lengthening of diastole, reducing outflow-obstruction, and inducing a beneficial remodelling resulting in a larger left ventricular cavity, and improved stroke volume. Hypertrophic cardiomyopathy is associated with increased activity of cardiac sympathetic nerves, and infants in heart failure with hypertrophic cardiomyopathy show signs of extreme sympathetic over-activity, and require exceptionally high doses of beta-blockers to achieve effective betablockade as judged by 24 h Holter recordings, often 8-24 mg/kg/day of propranolol or equivalent.

Conclusion: Beta-blocker therapy is without doubt the treatment of choice for patients with heart failure caused by hypertrophic cardiomyopathy, but the dose needs to carefully titrated on an individual basis for maximum benefit, and the dose required is surprisingly large in infants with heart failure due to hypertrophic cardiomyopathy.

Structure, Function, and Pathogenesis of SHP2 in Developmental Disorders and Tumorigenesis

Src homology 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2), encoded by the human PTPN11 gene, is a ubiquitously expressed protein tyrosine phosphatase (PTP) that consists of two tandem Src homology (SH2) domains (N-SH2 and C-SH2), a PTP catalytic domain, and a C-terminal tail with tyrosyl phosphorylation sites. It plays critical roles in numerous cellular processes through the regulation of various signaling pathways in PTP catalytic activity-dependent and -independent manners. Dysfunction of SHP2 resulting from pathogenic mutations and aberrant expression leads to the dysregulation of multiple signaling pathways, thus contributing to different human disorders. Germline and somatic mutations in PTPN11 are involved in Noonan syndrome (NS), LEOPARD syndrome (LS), and hematological malignancies, as well as several solid tumors. In this report, we provide an overview of the current knowledge of the structure and function of SHP2, and further discuss the molecular and pathogenic mechanism of SHP2 in human diseases, with a special focus on tumorigenesis. Furthermore, we summarize that SHP2 might itself represent a potential drug target for cancer prevention and treatment. Ongoing research and development of SHP2-specific inhibitors would enhance this potential.

SHP-2 Regulates Growth Factor Dependent Vascular Signalling and Function

Cellular responses to the environment are mediated by intracellular signalling pathways monitoring several essential cellular processes, such as proliferation, migration, differentiation and survival. Cellular dysfunction is caused by dysregulation of intracelleular signalling pathways and may ultimately result in pathophysiological conditions. The non- transmembrane protein tyrosine phosphatase SHP-2 has been shown to be important for the control of cellular behaviour. It influences the activity of several growth factor and cytokine dependent signalling pathways by association with growth factor receptors, cell surface adhesion molecules and adaptor molecules such as Gab-1, Grb2 and IRS-1. Upon FGF-2, EGF and insulin stimulation SHP-2 regulates MAPK pathway activation. In addition, SHP-2 is involved in the regulation of cell survival by influencing the PI3-K/Akt pathway upon EGF, IGF and PDGF stimulation. Due to these properties, SHP-2 function has recently gained more interest in vascular processes, such as in the differentiation of cardiac progenitor cells and angiogenic events. Indeed, SHP-2 was shown to positively regulate endothelial cell motility and angiogenesis in vitro and in vivo as well as controlling intracellular pH of endothelial and vascular smooth muscle cells. On the other hand, SHP-2 was also demonstrated to be responsible for down regulation of VEGF receptor 2 activation upon dopamin and collagen stimulation. Finally, mutations in the Ptpn11 gene (encoding SHP-2) underlie the developmental disorders Noonan syndrome and Leopard syndrome characterized by congenital heart disease and hematologic abnormalities. Different mutations in this gene also result in myeloid and lymphoid malignancies. This article summarizes the role of SHP-2 in signalling pathways relevant for vascular biology and associated disorders.

Medical Treatment of Aortic Aneurysms in Marfan Syndrome and other Heritable Conditions

Thoracic aortic aneurysms can be triggered by genetic disorders such as Marfan syndrome (MFS) and related aortic diseases as well as by inflammatory disorders such as giant cell arteritis or atherosclerosis. In all these conditions, cardiovascular risk factors, such as systemic arterial hypertension, may contribute to faster rate of aneurysm progression. Optimal medical management to prevent progressive aortic dilatation and aortic dissection is unknown. β-blockers have been the mainstay of medical treatment for many years despite limited evidence of beneficial effects. Recently, losartan, an angiotensin II type I receptor antagonist (ARB), has shown promising results in a mouse model of MFS and subsequently in humans with MFS and hence is increasingly used. Several ongoing trials comparing losartan to β -blockers and/or placebo will better define the role of ARBs in the near future. In addition, other medications, such as statins and tetracyclines have demonstrated potential benefit in experimental aortic aneurysm studies. Given the advances in our understanding of molecular mechanisms triggering aortic dilatation and dissection, individualized management tailored to the underlying genetic defect may be on the horizon of individualized medicine. We anticipate that ongoing research will address the question whether such genotype/pathogenesis-driven treatments can replace current phenotype/syndromedriven strategies and whether other forms of aortopathies should be treated similarly. In this work, we review currently used and promising medical treatment options for patients with heritable aortic aneurysmal disorders.

Design Potential Selective Inhibitors for Treating Cancer by Targeting the Src Homology 2 (SH2) Domain-Containing Phosphatase 2 (Shp2) with Core Hopping Approach

Due to the vital role in many cell regulatory processes, such as cell cycle control, survival and apoptosis, as well as growth and neurotransmitter signaling, Src homology 2 (SH2) domain-containing phosphatase 2(Shp2) has attracted considerable attention for developing drugs to treat cancers. In this study, by means of the powerful “core hopping” technique, a novel class of inhibitors was discovered based on the compound II-B08. It was observed by molecular dynamics simulations that these novel inhibitors not only possessed the same function as II-B08 did in inhibiting Shp2, but also had stronger binding to the receptor. It was further validated by the outcomes of their ADME (absorption, distribution, metabolism, and excretion) predictions that the new inhibitors hold high potential to become promising drug candidates for developing novel and powerful drugs for anticancer. Subsequently, in vitro evaluation of promising hits revealed a novel and selective inhibitor of Shp2.

Tissue Engineering Techniques in Cardiac Repair and Disease Modelling

Cell therapy has been proposed to treat patients with end-stage heart failure. However, it has been suggested that the significant mechanical forces in an often ischaemic, inflamed, biochemically hostile environment may cause poor cell survival and retention. It is hypothesised that tissue engineering techniques could be used to modify the environment to improve the efficacy of cell therapy. Similarly, it has been suggested that tissue engineering technology could be used to mature the phenotype of immature cardiomyocytes in vitro, making them more useful disease models. In this review we will briefly discuss key tissue engineering techniques and principles that can be used to facilitate cell therapy, and modify the phenotype of immature cardiomyocytes and stem cells.

Induced Pluripotent Stem Cells in Regenerative Medicine and Disease Modeling

In 2006, Dr. Yamanaka created the induced pluripotent stem cell (iPSC) by reprogramming adult fibroblasts back to an immature, pluripotent state. Effectively bypassing the ethical constraints of human embryonic stem cells, iPSCs have expanded the horizons of regenerative medicine by offering a means to derive autologous patient-matched cells and tissues for clinical transplantation. However, persisting safety concerns must be addressed prior to their widespread clinical application. In this review, we discuss the history of iPSCs, derivation strategies, and current research involving gene therapy and disease modeling. We review the potential of iPSCs for improving a range of cell-based therapies and obstacles to their clinical implementation.

Induced Pluripotent Stem Cell-Based Studies of Parkinson's Disease: Challenges and Promises

A critical step in the development of effective therapeutics to treat Parkinson’s disease (PD) is the identification of molecular pathogenic mechanisms underlying this chronically progressive neurodegenerative disease. However, while animal models have provided valuable information about the molecular basis of PD, the lack of faithful cellular and animal models that recapitulate human pathophysiology is delaying the development of new therapeutics. The reprogramming of somatic cells to induced pluripotent stem cells (iPSC) using delivery of defined combinations of transcription factors is a groundbreaking discovery that opens great opportunities for modeling human diseases, including PD, since iPSC can be generated from patients and differentiated into disease-relevant cell types, which would capture the patients’ genetic complexity. Furthermore, human iPSC-derived neuronal models offer unprecedented access to early stages of the disease, allowing the investigation of the events that initiate the pathologic process in PD. Recently, human iPSC-derived neurons from patients with familial and sporadic PD have been generated and importantly they recapitulate some PD-related cell phenotypes, including abnormal α-synuclein accumulation in vitro, and alterations in the autophagy machinery. This review highlights the current PD iPSC-based models and discusses the potential future research directions of this field.

Enzymatic Properties and Physiological Roles of Cytosolic 5’-Nucleotidase II.

Cytosolic 5'-nucleotidase II (cN-II) is an intracellular 5'-nucleotidase characterized by substrate specificity. It preferentially hydrolyzes 6-hydroxypurine nucleotides such as IMP and GMP over AMP or UMP. cN-II is allosterically activated by ATP and inhibited by inorganic phosphate. It also has phosphotransferase activity and transfers phosphate moieties from IMP or GMP to nonphysiological nucleoside analogues used to treat some viral infections or malignancies. The cN-II gene has a strikingly conserved primary structure from humans to nematodes and its activity has been detected in various animals including snails. Its activity is highest in the livers of birds, crocodiles, lizards and snakes. The activity in chicken liver increases 2-fold by feeding a high-protein diet. These results suggest that cN-II participates, through IMP dephosphorylation, in production of uric acid as the main end product of aminonitrogen in these animals. Some studies suggest that cN-II participates in dephosphorylation of IMP accumulated in cells of some tissues to diffusible inosine for reutilization by other tissues. It has also been proposed that cN-II, together with purine nucleoside phosphorylase and hypoxanthine-guanine phosphoribosyltransferase, constitutes the “oxypurine cycle”, thus regulating intracellular phosphoribosyl pyrophosphate (PRPP) concentrations. As for intracellular dephosphorylation of AMP, another intracellular 5'-nucleotidase, cN-I, is supposed to participate, because it hydrolyzes AMP more preferentially than IMP or GMP. However, for the tissues, in which the expression of cN-I is very low or undetectable, e.g. liver or brain tissues, results have been obtained that suggest the participation of cN-II in intracellular dephosphorylation of AMP.

Improved Hepatic Differentiation Strategies for Human Induced Pluripotent Stem Cells

Based on their almost unlimited self-renewal capacity and their ability to differentiate into derivatives of all three germ layers, human induced pluripotent stem cells (hiPSCs) might serve as a preferable source for hepatic transplants in metabolic liver disorders or acute liver failure. Furthermore, the generation of patientspecific hiPSCs might facilitate the development of innovative therapeutic strategies by accurately modelling disease in vitro. In our study, we aimed for an efficient hepatic differentiation protocol that is applicable for both human embryonic stem cells (hESCs) and hiPSCs. We attempted to accomplish this goal by using a cytokine and small molecule-based protocol for direct differentiation of hESCs and hiPSCs into hepatic cells. Selecting differentiated hepatic cells was possible using an albumin promoter-driven G418 resistance system. Due to IRES-dependent dTomato reporter expression, we were able to track hepatic differentiated cells and we evaluated the most efficient time frame for G418 selection. The status of hepatic differentiation was determined by qRT-PCR comparing the expression of hepatic markers such as AFP, ALB, SOX17, and HNF4 to standard hepatic cells. Functional analysis of the hepatic phenotype was obtained by measuring secreted albumin levels and by analysis of cytochrome P450 type 1A1 activity (EROD). The percentage of differentiated cells was quantified by FACS analysis. In conclusion, our improved protocol demonstrates that both pluripotent cell sources (hESC and hiPSC) can efficiently be differentiated into mature hepatic cells with functional characteristics similar to those of standard hepatic cell lines such as HepG2.

Modelling Human Disease with Pluripotent Stem Cells

Recent progress in the field of cellular reprogramming has opened up the doors to a new era of disease modelling, as pluripotent stem cells representing a myriad of genetic diseases can now be produced from patient tissue. These cells can be expanded and differentiated to produce a potentially limitless supply of the affected cell type, which can then be used as a tool to improve understanding of disease mechanisms and test therapeutic interventions. This process requires high levels of scrutiny and validation at every stage, but international standards for the characterisation of pluripotent cells and their progeny have yet to be established. Here we discuss the current state of the art with regard to modelling diseases affecting the ectodermal, mesodermal and endodermal lineages, focussing on studies which have demonstrated a disease phenotype in the tissue of interest. We also discuss the utility of pluripotent cell technology for the modelling of cancer and infectious disease. Finally, we spell out the technical and scientific challenges which must be addressed if the field is to deliver on its potential and produce improved patient outcomes in the clinic.

Induced Pluripotent Stem Cells and Their Potential for Basic and Clinical Sciences

Induced pluripotent stem (iPS) cells, are a type of pluripotent stem cell derived from adult somatic cells. They have been reprogrammed through inducing genes and factors to be pluripotent. iPS cells are similar to embryonic stem (ES) cells in many aspects. This review summarizes the recent progresses in iPS cell reprogramming and iPS cell based therapy, and describe patient specific iPS cells as a disease model at length in the light of the literature. This review also analyzes and discusses the problems and considerations of iPS cell therapy in the clinical perspective for the treatment of disease.

Small Molecules in Stem Cell Research

Stem cells possess great promise as therapeutic tools for neurological disorders such as neurodegenerative diseases (Parkinson’s disease and Huntington’s disease), cerebrovascular diseases (stroke), neurotraumata (spinal cord injury) and demyelinating diseases (multiple sclerosis). This aspiration is based on the cells` ability to maintain a status of self-renewal and to differentiate into the various cell types of an organism. The use of the cells ranges from in vitro to in vivo studies in animal models, ending with clinical applications in humans. The self-renewal and commitment of stem/progenitor cells to differentiate and mature involves complex events leading to the generation of different phenotypes via distinctive developmental programs. Small molecules provide a tool with which to influence these regulatory changes in a controlled manner and to help understand the underlying mechanisms. Furthermore, substantial progress in generating induced pluripotent stem cells has been made using small molecules to replace reprogramming factors and enhance the reprogramming efficiency and kinetics, thus generating cells more compatible with the requirements for cell replacement therapies. In this review we will present the recent progress on the use of small molecules in embryonic and induced pluripotent stem cell research. In the final section we will give a short summary of the clinical approaches using these cells.

Recent Patents Related to Phosphorylation Signaling Pathway on Cancer

Phosphorylation and dephosphorylation play an important role in the regulation of growth factor and cytokine signal transduction to modulate cell proliferation, differentiation, survival, and apoptosis. In some cellular systems, the information suggests that EGFR, somatostatin receptors, SHP-1, Akt and PI3K can regulate carcinogenesis implied process through regulated the activity of NF-κB. Current patents related to signaling pathway that includes somatostatin receptors, phosphotyrosine phosphatases, tyrosine kinases, AKT/PKB and PI3K are focusing in diagnosis, prognosis and treatment. Many recent patented techniques include inhibition, antagonism or alternative therapeutic methods. Furthermore, it is necessary to deepen understanding of the molecular mechanisms involved in cancer to develop other alternative therapies focusing not only on new inhibitors.

The Future of Induced Pluripotent Stem Cells for Cardiac Therapy and Drug Development

The field of stem cell research was revolutionized with the advent of induced pluripotent stem cells. By reprogramming somatic cells to pluripotent stem cells, most ethical concerns associated with the use of embryonic stem cells are overcome, such that many hopes from the stem cell field now seem a step closer to reality. Several methods and cell sources have been described to create induced pluripotent stem cells and we discuss their characteristics in terms of feasibility and efficiency. From these cells, cardiac progenitors and cardiomyocytes can be derived by several protocols and most recent advances as well as remaining limitations are being discussed. However, in the short time period this technology has been around, evidence emerges that induced pluripotent stem cells may be more prone to genetic defects and maintain an epigenetic memory and thus may not be entirely the same as embryonic stem cells. Despite the lack of a complete fundamental understanding of stem cell biology, and even more of ways how to coax them into defined cell types, the technology is quickly adopted by industry. This paper gives an overview of the current applications of induced pluripotent stem cells in cardiovascular drug development and highlights active areas of research towards functional repair of the damaged heart. Adult stem cells have already been taken to clinical trials and we discuss these results in light of potential and hurdles to be taken to move induced pluripotent stem cells to the clinic.

Prenyloxyphenylpropanoids as a Novel Class of Anti-inflammatory Agents

Oxyprenylated natural products (isopentenyloxy-, geranyloxy- and the less spread farnesyloxy- compounds and their biosynthetic derivatives) represent a family of secondary metabolites that have been considered for years just as biosynthetic intermediates of the most naturally widespread C-prenylated derivatives. Only in the last decade have these natural products been recognized as interesting and valuable biologically active phytochemicals. Up to now about 300 molecules were isolated from plants mainly belonging to the families of Rutaceae, Apiaceae, and Compositae, comprising common edible vegetables and fruits. A wide variety of compounds containing a prenyloxy side chain has been isolated and among these coumarins, cinnamic acids and aromatic ketones displayed the most efficient and promising biological activities as anti-inflammatory agents. The aim of this review is to examine in detail the anti-inflammatory properties of these novel class of natural products.

Antimicrobial Peptides Present in Mammalian Skin and Gut are Multifunctional Defence Molecules

Antimicrobial peptides are major components of the innate immune defence. They are well conserved along evolution, nontoxic and they ensure potent defences against a large number of pathogens. They act by direct killing of microorganisms and they possess additional roles in the regulation of adaptive immune responses, by recruting or stimulating immune cells. Skin and gut are positioned at the interface of internal milieu and external environment. They represent a physical and chemical barrier against pathogens invasion and the antimicrobial peptides limit pathogen growth in normal conditions. During infection or injury, some of these peptides are overexpressed and disrupt microbial membranes and/or stimulate immune cell recruitment, allowing to return to homeostasis or to increase inflammation. Antimicrobial peptides expression is altered in several diseases: α-defensins deficiency is related with Crohns disease and in skin, cathelicidin LL-37 and β-defensin-2 are overexpressed in psoriasis, while in atopic dermatitis, their expression is decreased. The present review provides an up-to-date summary of the expression and the biological roles of the antimicrobial peptides found in the skin and gastrointestinal mucosa of the host, in normal and pathological conditions. The involvement of these natural antimicrobial peptides in inflammation, is also discussed.

Phosphotyrosine Phosphatases in Cancer Diagnostic and Treatment

The activation of proteins by post-translational modification represents an important cellular mechanism for regulating most aspects of biological organization and control, including growth, development, homeostasis, and cellular communication. The complexity of protein modification includes phosphorylation and dephosphorylation, on proteins of different signaling pathways corresponding to growth, development, disease states, and aging. Current patents in phosphotyrosine phosphatases signaling pathway are focusing in diagnosis, prognosis and treatment. Many, new diagnosis techniques detect changes in mRNA expression with microarray technologies and others introduced specific antibodies for detection proteins changes, introducing to Biomedicine at Transcriptomic and Proteomic era. Many recent invent development alternative therapy with antibodies and inhibitors to PTPs that demonstrate the need to deepen understanding of the molecular mechanisms involved in the development of cancer.

Feline Immunodeficiency Virus Model for Designing HIV/AIDS Vaccines

Feline immunodeficiency virus (FIV) discovered in 1986 is a lentivirus that causes AIDS in domestic cats. FIV is classified into five subtypes (A-E), and all subtypes and circulating intersubtype recombinants have been identified throughout the world. A commercial FIV vaccine, consisting of inactivated subtype-A and -D viruses (Fel-O-Vax FIV, Fort Dodge Animal Health), was released in the United States in 2002. The United States Department of Agriculture approved the commercial release of Fel-O-Vax FIV based on two efficacy trials using 105 laboratory cats and a major safety trial performed on 689 pet cats. The prototype and commercial FIV vaccines had broad prophylactic efficacy against global FIV subtypes and circulating intersubtype recombinants. The mechanisms of cross-subtype efficacy are attributed to FIV-specific T-cell immunity. Findings from these studies are being used to define the prophylactic epitopes needed for an HIV-1 vaccine for humans.

Drug Discovery and Protein Tyrosine Phosphatases

Protein tyrosine phosphatases (PTPs) play a critical role in physiological signaling pathways by controlling the level of tyrosine phosphorylation. The past decade has seen a vast increase in both academic and industrial interest in PTPs and their relevance as potential therapeutic targets, with several PTP inhibitors recently entering clinical trials. Despite these developments, there are numerous examples of failed PTP drug discovery programs, such that PTPs have attained a reputation as ‘undruggable’ targets. This review attempts to illustrate the many obstacles that must be overcome to successfully develop a PTP drug, ranging from validation of PTPs as therapeutic targets to the difficulties of assessing the true inhibitory nature of apparently well-behaved compounds, along with the need to balance the physiocochemical properties required for active site binding with the characteristics needed for in vivo activity. A number of examples of structure-based design are presented, along with cautionary tales of PTP inhibitor programs that have failed due to unexpected shortcomings.

Antibodies for Therapeutic Uses and the Evolution of Biotechniques

Protein therapeutics are playing an expanding role in modern medicinal chemistry. Among them, native or engineered molecules exploiting the binding and catalytic potential of the immune repertoire form an extremely exciting and emerging business area. They represent by far the single largest category of biopharmaceutical substances under investigation. The fast increase of this pharmaceutical category paralleled the scientific and technical progress from murine to chimeric, humanized and, finally, human engineered antibodies. Indeed, the development of the phage display technology, allowing libraries of shuffled murine or human antibody binding domains to be screened for affinity against a selected target antigen or activity against a specific reaction substrate, open new perspectives, disclosing the opportunity to circumvent restrictions inherent to the in vivo immunisation. Transgenic technology represents another powerful method for generating fully human monoclonal antibodies against a wide variety of drug targets, while recombinant technology continues to evolve, improving the pharmacodynamic and pharmacokinetic properties of antibody therapeutics, with the production of different antibody constructs or formats, such as bispecific antibodies, diabodies and others, and different functional activities, such as catalysis, cellular internalisation and antigen-mimicking. The aim of the present review is to overview native or recombinant antibodies while discussing the underlying antibody technology, with the aim to favour understanding of the antibody therapeutics that are in use or will enter market in the near future.

Role of Tyrosine Phosphatase Inhibitors in Cancer Treatment with Emphasis on SH2 Domain-Containing Tyrosine Phosphatases (SHPs)

Protein tyrosine phosphorylation is one of the key mechanisms involved in signal transduction pathways. This modification is regulated by concerted action of protein tyrosine phosphatases and protein tyrosine kinases. Deregulation of either of these key regulators lead to abnormal cellular signaling, which is largely associated with human pathologies including cancer. Although the role of protein tyrosine kinases in cancer is well established, less is known about the involvement of protein tyrosine phosphatases in carcinogenesis and tumor progression. Moreover, several inhibitors targeting protein tyrosine kinases have demonstrated their value in cancer treatment, while interest in protein tyrosine phosphatases as a target for treatment has risen more recently. In this review we describe the progressive efforts and challenges concerning the development of drugs targeting phosphatases as promising novel cancer therapies. We focus on two key regulatory SH2 domain-containing phosphatases, SHP-1 and SHP-2 and one of their substrates, signal regulatory protein alpha. Since SHPs have been linked to many different malignancies, protein tyrosine phosphatases could offer a great spectrum of new, targeted drugs.

Evasion of Ribonuclease Inhibitor as a Determinant of Ribonuclease Cytotoxicity

Onconase® (ONC) is an amphibian member of the bovine pancreatic ribonuclease (RNase A) superfamily that exhibits innate antitumoral activity. ONC has been granted both orphan-drug and fast-track status by the U.S. Food and Drug Administration for the treatment of malignant mesothelioma, and is poised to become the first chemotherapeutic agent based on a ribonuclease. Investigations into the mechanism of ribonuclease-based cytotoxicity have elucidated several important determinants for cytotoxicity, including efficient deliverance of ribonucleolytic activity to the cytosol and preservation of conformation stability. Nevertheless, the most striking similarity between ONC and bovine seminal ribonuclease, another naturally cytotoxic ribonuclease, is their insensitivity to inhibition by the potent cytosolic ribonuclease inhibitor protein (RI). RI typically binds to its ribonuclease ligands with femtomolar affinity — an extraordinary feat considering the lack of sequence identity among the bound ribonucleases. Mammalian ribonucleases such as RNase A or its human homologue, RNase 1, have the potential to be more desirable chemotherapeutic agents than ONC owing to their higher catalytic activity, low potential for immunogenicity, favorable tissue distribution, and high therapeutic index, but are limited by their sensitivity to RI. These non-toxic mammalian ribonucleases can be transformed into potent cytotoxins by engendering them with RI-evasion using protein engineering strategies such as site-directed mutagenesis, multimerization, fusion to a targeting moiety, and chemical modification. In several instances, these engineered ribonucleases exhibit greater cytotoxicity in vitro than does ONC. Herein, we review the biochemical characteristics of RI ribonuclease complexes and progress towards the development of mammalian ribonuclease-based chemotherapeutics through the elicitation of RI-evasion.

Pandemic Influenza: Preventing the Emergence of Novel Strains and Countermeasures to Ameliorate its Effects

Influenza is a seasonal disease that peaks every year in the winter months. Antigenic drift of the viral surface proteins, particularly the hemagglutinin (HA), is responsible for the viruss ability to evading the hosts immune system, and for the severity of the disease. Pandemic influenza arises when an influenza virus carrying a novel HA gene enters into the naive human population, resulting in excess morbidity and mortality. Three major influenza pandemics were experienced in the last century and the emergence of a new pandemic strain is considered a matter of time. Our current understanding suggests that pandemic influenza strains arise from influenza viruses circulating in the natural reservoir, although the presence of intermediate hosts is considered essential in this process. Pigs and land-based birds have been shown to play a major role in the ecology of influenza viruses by providing an environment in which influenza viruses can change their phenotype, expand their host range, and eventually transmit to humans. In recent years, a great detail of attention has been placed on understanding the epidemiological and molecular factors that can lead to interspecies transmission of influenza viruses. In this review we will discuss the ecological and molecular aspects that lead to pandemic influenza as well as the intervention strategies at our disposal that can reduce the emergence of pandemic influenza strains and/or minimize their effects.

The Role of SHP-2 in Cell Signalling and Human Disease

The activation and transduction of several signalling pathways are dependent on tyrosine phosphorylation. The non-transmembrane protein tyrosine phosphatase SHP-2 (Src homology 2 domain containing tyrosine phosphatase 2) has been shown to be involved in several signalling pathways initiated by different growth factors, cytokines, hormones and extracellular matrix receptors. SHP-2 directly interacts with several growth factors, cell surface adhesion molecules and different adaptor molecules such as the Grb 2 associated binder 1 (Gab-1), Grb2 and the insulin receptor substrate 1 (IRS- 1). It has been shown to be required for activation of the mitogen activated protein kinase (MAP-Kinase) pathway upon fibroblast growth factor (FGF), epidermal growth factor (EGF) and insulin stimulation. Moreover, SHP-2 has been found to influence the phosphoinositide 3-Kinase (PI3-Kinase)/kt pathway upon stimulation with EGF, insulin like growth factor (IGF) and platelet derived growth factor (PDGF), thus affecting cell survival. SHP-2 also plays a negative role in certain signalling pathways, such as the janus activated kinase (JAK)-signal transducers and activators of transcription (STAT) pathway. Recently, SHP-2 has become clinically relevant as germ-line missense mutations in the gene encoding SHP-2 (Ptpn11) have been found to cause the developmental disorders Noonan syndrome and the Leopard syndrome. Other mutations in this gene lead to myeloid and lymphoid malignancies. Moreover, SHP-2 has also been implicated to play a role in diabetes and in the development of gastric adenocarcinoma following H. Pylori infection. This article deals with the role of SHP-2 in different signalling pathways and the involvement of SHP-2 in human disorders.

Previously Apparently Undescribed Autosomal-Recessive Multiple Congenital Anomalies/ Mental Retardation (MCA/MR) Syndrome Comprising: Fronto-Nasal Dysplasia, Hypertelorism, Short Stature and Brachydactily

We describe two sisters born to a consanguineous Arab Muslim couple in northern Israel. Among other clinical findings, both have moderate mental retardation, short stature, “leonine” facies, hypertelorism, broad nasal root, long philtrum, fronto-nasal dysplasia, pigmented lesions of the irises, brachy-clinodactily, apparantly low-set posteriorly angulated ears and a webbed neck. This association of anomalies defines a new syndrome. Parental consanguinity and familial occurrence in two sisters suggest autosomal recessive inheritance.

Antimicrobial Peptides in Oral Cancer

There is increasing evidence that antimicrobial peptides (AMPs) are differentially regulated in cancers such as oral squamous cell carcinomas (OSCC). Data showing that AMPs influence the growth of tumor cells, exhibit direct cytotoxic activity towards cancer cells, function as a tumor suppressor gene or activate the adaptive immunity suggest that a dysregulation of AMPs may be associated with the development of cancer. There is no question that, with increasing resistance against conventional chemotherapy, novel anticancer agents are needed. It is interesting to speculate that natural AMP or synthetic derivatives can be used to develop novel strategies to fight cancer diseases and may represent a novel family of anticancer agents. However, future research is needed to employ the role of AMPs in cancer and to investigate their role as potential anticancer drugs.