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Clinical Oncology

DECEMBER 30, 2019

[Cell death]

KOPPER László, TÍMÁR József

[Cell proliferation and cell death (mainly apoptosis) have programs forming a network to maintain the functional integrity of the organism. Apoptosis has an external and internal units with ligands, signalling pathways and targets. Besides, some other participants (e.g. p53) are involved in the regulation of cell death. Although, apoptosis is a multitargeted process, there is no useful therapy, if it is needed, to correct accumulation of unwanted cells.]

Clinical Oncology

DECEMBER 10, 2018

[PI3K–AKT–mTOR pathway as a therapeutic target]

KOPPER László

[The PI3K-AKT-mTOR is one of the most busy signalling pathway, accepting and sending the message to the effector compartment. The pathway is very complex with activators (see the name), and inhibitors, as PTEN. Depending of the cell type this pathway participates in almost all functions of a given cell. The members of the pathway may have genetic failures, as a consequence, the risk for the development of different diseases, including cancer is high. Therefore it is logical to produce drugs to inhibit the dysregulated function. Unfortunately, despite the promising preclinical effectivity, so far only 4 drugs can be used to treat cancer patients. There are some hypothesis for the in effectivity, e.g. no useful marker for patient selection, high toxicity, false drivers for targeting. What is sure, combination therapy is much better than monotherapy]

Clinical Oncology

MAY 10, 2017

[Signaling pathways in cancer stem cells (Notch, Hedgehog, Wnt)]

KOPPER László, NAGY Noémi, SEBESTYÉN Anna

[OThe key regulators in the embryonic life, and later in the differentiation of tissues and organs are the evolutionary reserved signalling pathways, as Notch, Hedgehog and Wnt. Mutations of these pathways have been identifi ed in many tumor types, increasing the risk to the appearance of cancer stem cells (CSC), with very similar geno- and phenotype as normal stem cells have. Such CSCs with stemness functions can be developed not only from normal stem cells, but also from progenitor and differentiated cells. The main characteristics of CSC are the self maintenance, slow growth rate, very effective DNA-repair system, etc. All of these can contribute to the resistance. Further problems are the low number of CSC in the whole tumor mass, which makes rather diffi cult to achieve the effective drug concentration in CSC. The mentioned ancient pathways interact with many other pathways to form a network, which can infl uence the strategy of therapy. No doubt, that these pathways are promising targets, however, till now the clinical effectiveness is very low due to some reasons mentioned above. Nevertheless, some drugs are already in clinical use, either as monotherapy or part of the combinations. Little is known about the relationship between the pathways and the microenvironment, which has an outstanding role in the cellular activities, sometimes resulting opposite output. It is a great challenge to design effective drugs against CSC, similarly to fi nd reliable predictive biomarkers, which unfortunately still missing, since a reasonable drug-marker interactions would speed up the personalized treatment.]

Clinical Oncology

FEBRUARY 20, 2014

[Management of renal cancer]

MARÁZ Anikó, SZŰCS Miklós

[Targeted anti-cancer agents are used as standard therapies in case of advanced or metastatic clear cell renal carcinoma. Neovascularisation plays an important role in the progression of hypervascularized cancers. Vascular endothelial growth factor (VEGF) is the key molecule in this mechanism. Most of the registered agents inhibit the angiogenesis by blocking the VEGF signalling pathway. It can occur if an antibody binds to the VEGF, so the linkage to the receptor is blocked. This happens in case of bevacizumab. Another mechanism is the inhibition of the intracellular compound of VEGF receptor by tyrosine kinase inhibitors (TKI). Sorafenib, sunitinib, pazopanib and axitinib belong to this group. Other well-known mechanism of action is the inhibition of mammalian target of rapamycin (mTOR) receptor, like temsirolimus and everolimus. Based on randomised controlled trials sunitinib, pazopanib or IFNα-bevacizumab combination is recommended fi rst-line according to the international recommendations in case of good and moderate prognosis. For patients with poor prognosis temsirolimus is the standard therapy. In second-line, after ineffective cytokine therapy, sorafenib, pazopanib and axitinib are the supported options. If TKI is ineffective, everolimus or axitinib can be administered. In the latest recommendations sorafenib is another possible option (off label). After two TKIs, only everolimus is registered for third-line therapy. Life expectancy of patients can further be improved as the number of targeted drugs increases, more effective agents appear and as appropriate sequences and their benefi cial effects are recognised.]

Clinical Oncology

FEBRUARY 20, 2014

[Resistancy and/or progression - Failure or only a short stop]

KOPPER László, SEBESTYÉN Anna

[Nowadays, with the continuously in creasing demand for targeted diagnostics and therapy, we are approaching an ideal stage when the most effective treat ment for a given patient could be selected. However, some basic problems are still waiting to be solved. One major hurdle is the heterogeneity, the formation of subclones with different signifi cance during progression, but with the capacity to overgrow after the failure of the initial therapy. The importance of this phenomenon is refl ected in the daily practice where targeted therapy is allowed to treat only locally extended or metastatizing tumors. Therefore, it is not as to nishing, that the clinical success is usually tem po rary, the disease in spite of the good response at the beginning will progress. The main reason is the resistancy against the carefully analysed and applied therapeutic drugs, which has several options (e.g. new mutations, crosstalks between pathways, faults of feed-backs, etc.). This review focuses on the acquired resistancy with some relevant examples. Among the open questions we can recall e.g. the resistancy in combination therapy, or the suggested link between resistancy and progression including the potential use of drug rechallenge.]

Hypertension and nephrology

FEBRUARY 28, 2011

[The importance of epithelial-mesenchymal transition in kidney fibrosis]

NAGY SZAKÁL Dorottya, SZEBENI Beáta, SZIKSZ Erna, HIMER Leonóra, REUSZ György, VÁSÁRHELYI Barna, TULASSAY Tivadar, VANNAY Ádám

[Epithelial-mesenchymal transition (EMT) plays a central role in physiological and pathological processes of embryogenesis, carcinogenesis and tissue fibrosis. During EMT epithelial cells may transform to myofibroblasts, which are the effector cells of fibrosis. In our summary the process of EMT and its medical importance will be reviewed in relation to renal fibrosis. Regardless of the initiating cause the final common mechanism of organ fibrosis is similar in the different chronic renal diseases. It always involves major inflammatory responses, however the molecular mechanisms involved are still elusive. The EMT now takes centre stage as the point of convergence between inflammation and the progression of degenerative fibrotic diseases. Understanding the pathomechanism of EMT and the significance of signalling pathways involved in this process may lead to a new therapeutic approach in the treatment of chronic renal diseases.]

Lege Artis Medicinae

JULY 14, 2007

[CONTROVERSIAL EFFECTS OF NITRIC OXIDE: INTEGRITY AND TOXICITY]

KISS Róbert Gábor, BÉRES Bernát János

[Nitric oxide is a key molecule of the human body. Since its discovery, a library of books and papers have been published on its physiological and pathophysiological role. It is involved in almost all pathological processes. In healthy individuals nitric oxide plays a crucial role in the vascular regulation by protecting against atherosclerosis, myocardial infarction and stroke. In the central nervous system, nitric oxide in its function as a neurotransmitter is responsible for synaptic plasticity, long-term potentiation, memory and a number of neuroendocrine control mechanisms. Furthermore, during inflammation and host defense, macrophages and neutrophils produce nitric oxide that has antibacterial, antiviral, and tumour cell killing activity. In pathologic conditions, however, nitric oxide reacts with superoxide anion to form peroxynitrite that damages the enzymes of the mitochondrial respiratory chain, superoxide-dismutase, reduced glutathion and activates or inactivates signalling molecules. During ischaemia- reperfusion, nitric oxide and peroxynitrite contribute to nitrative/nitrosative stress, DNAfragmentation and consequent polyADP-ribosepolymerase- 1 enzyme activation both in coronary thrombosis and ischaemic stroke.]

Clinical Neuroscience

MARCH 20, 2007

[BRAIN INSULIN SIGNALLING IN THE REGULATION OF ENERGY BALANCE AND PERIPHERAL METABOLISM]

MICHAELA Diamant

[The unparalleled global rates of obesity and type 2 diabetes, together with the associated cardiovascular morbidity and mortality, are referred to as the "diabesity pandemic". Changes in lifestyle occurring worldwide, including the increased consumption of high-caloric foods and reduced exercise, are regarded as the main causal factors. Central obesity and insulin resistance have emerged as important linking components. Understanding the aetiology of the cluster of pathologies that leads to the increased risk is instrumental in the development of preventive and therapeutic strategies. Historically, skeletal muscle, adipose tissue and liver were regarded as key insulin target organs involved in insulinmediated regulation of peripheral carbohydrate, lipid and protein metabolism. The consequences of impaired insulin action in these organs were deemed to explain the functional and structural abnormalities associated with insulin resistance. The discovery of insulin receptors in the central nervous system, the detection of insulin in the cerebrospinal fluid after peripheral insulin administration and the well-documented effects of intracerebroventricularly injected insulin on energy homeostasis, have identified the brain as an important target for insulin action. In addition to its critical role as a peripheral signal integrating the complex network of hypothalamic neuropeptides and neurotransmitters that influence parameters of energy balance, central nervous insulin signalling is also implicated in the regulation of peripheral glucose metabolism. This review summarizes the evidence of insulin action in the brain as part of the multifaceted circuit involved in the central regulation of energy and glucose homeostasis, and discuss the role of impaired central nervous insulin signalling as a pathogenic factor in the obesity and type 2 diabetes epidemic.]

Ca&Bone

SEPTEMBER 20, 2005

[The role of calcium in the chemoprevention of colorectal cancer]

FUSZEK Péter, SPEER Gábor

[One of the most exciting research areas of the past decade has concerned the chemoprevention of colorectal cancer (CRC). Numerous clinical studies have been conducted on the preventive role of NSAIDs, high fibre intake, selenium, phytooestrogens, hormone replacement therapy, antioxidants, COX-inhibitors, folic acid and calcium, however, their results are controversial. Among the suggested chemopreventive agents, the preventive role of calcium is supported by the strongest evidence.This paper aims to review the available facts on the role of calcium. Recent studies suggest that appropriate calcium intake may partially counterbalance the effect of the genes that contribute to the development of CRC. Experimental data show that calcium directly influences the expression of several genes involved in tumorigenesis and that it is also involved in a number of signalling pathways that control cell proliferation, differentiation and apoptosis.These effects mostly arise through the activation of the calcium sensing receptor. The main goal of this review is to draw attention to the established chemopreventive role of calcium in CRC. Published data suggest that a lifelong daily calcium intake between 1200 to 1500 mg (even 2000 mg in high risk groups) would significantly decrease the incidence of CRC by inhibition of tumorigenesis.]

Clinical Neuroscience

AUGUST 20, 2002

[The molecular genetic control of bony developmental malformations affecting the craniocervical junction and the cervical spine]

DÁVID Károly, KASÓ Gábor, THOROGOOD Peter V, STEVENS John M, CROCKARD H Alan

[In this review a new interpretation of the origin of bony developmental malformations affecting the craniocervical junction and the cervical spine is presented based on recent advances in the understanding of embryonic development of the spine and its molecular genetic control. Radiographs, CT and MRI scans or CT myelograms of patients with Klippel-Feil syndrome were used for demonstration. Detailed clinical and radiologial analysis of these patients was published earlier [David KM, Stevens JM, Thorogood P, Crockard HA. The dysmorphic cervical spine in Klippel-Feil syndrome: interpretations from developmental biology. Neurosurg Focus 1999;6(6):1.]. Homeotic transformation due to mutations or disturbed expression of Hox genes is a possible mechanism responsible for C1 assimilation. Notochordal defects and/or signalling problems, that result in reduced or impaired Pax-1 gene expression, may underlie vertebral fusions. This, together with asymmetrical distribution of paraxial mesoderm cells and a possible lack of communication across the embryonic mid-line, could cause the asymmetrical fusion patterns. The wide and flattened shape of the fused vertebral bodies, their resemblance to the embryonic cartilaginous vertebrae and the process of progressive bony fusion with age suggest that the fusions occur before or, at the latest, during chondrification of vertebrae. The authors suggest that the aforementioned mechanisms are likely to be, at least in part, responsible for the origin of the bony developmental malformations affecting the craniocervical junction and the cervical spine.]