Search

The rapid advances in nuclear medicine have resulted in significant advantages for the field of oncology. The focus is on the application of radiopharmaceuticals as therapeuticals. In addition, the latest developments in cell biology (the understanding of the cell structure, function, metabolism, genetics, signaling, transformation) have given a strong scientific boost to radiation oncology. In this regard, the article discusses what is soon going to be a new jump in radiation oncology based on the already accumulated considerable knowledge at the cellular level about the mechanisms of cell transformation and tumor progression, cell response to radiation, cell resistance to apoptosis and radiation and cell radio-sensitivity. The mechanisms of resistance of tumor cells to radiation and the genetically determined individual sensitivity to radiation in patients (which creates the risk of radiation-induced acute and late side effects) are the 2 major challenges to overcome in modern nuclear medicine. The paper focuses on these problems and makes a detailed summary of the significance of the differences in the ionizing properties of radiopharmaceuticals and the principle of their application in radiation oncology that will shed additional light on how to make the anti-cancer radiotherapies more efficient and safe, giving some ideas for optimizations.

Purpose Less than 20% of patients with melanoma who undergo sentinel lymph node (SLN) biopsy based on American Society of Clinical Oncology/Society of Surgical Oncology recommendations are SLN positive. We present a multi-institutional study to discover new molecular risk factors associated with SLN positivity in thin and intermediate-thickness melanoma. Patients and Methods Gene clusters with functional roles in melanoma metastasis were discovered by next-generation sequencing and validated by quantitative polymerase chain reaction using a discovery set of 73 benign nevi, 76 primary cutaneous melanoma, and 11 in-transit melanoma metastases. We then used polymerase chain reaction to quantify gene expression in a model development cohort of 360 consecutive thin and intermediate-thickness melanomas and a validation cohort of 146 melanomas. Outcome of interest was SLN biopsy metastasis within 90 days of melanoma diagnosis. Logic and logistic regression analyses were used to develop a model for the likelihood of SLN metastasis from molecular, clinical, and histologic variables. Results ITGB3, LAMB1, PLAT, and TP53 expression were associated with SLN metastasis. The predictive ability of a model that included these molecular variables in combination with clinicopathologic variables (patient age, Breslow depth, and tumor ulceration) was significantly greater than a model that only considered clinicopathologic variables and also performed well in the validation cohort (area under the curve, 0.93; 95% CI, 0.87 to 0.97; false-positive and false-negative rates of 22% and 0%, respectively, using a 10% cutoff for predicted SLN metastasis risk). Conclusion The addition of cell adhesion–linked gene expression variables to clinicopathologic variables improves the identification of patients with SLN metastases within 90 days of melanoma diagnosis.

Item does not contain fulltext Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase involved in development and human disease, including cancer. It is currently thought that the four-point one, ezrin, radixin, moesin (FERM)-kinase domain linker, which contains autophosphorylation site tyrosine (Y) 397, is not required for in vivo FAK function until late midgestation. Here, we directly tested this hypothesis by generating mice with FAK Y397-to-phenylalanine (F) mutations in the germline. We found that Y397F embryos exhibited reduced mesodermal fibronectin (FN) and osteopontin expression and died during mesoderm development akin to FAK kinase-dead mice. We identified myosin-1E (MYO1E), an actin-dependent molecular motor, to interact directly with the FAK FERM-kinase linker and induce FAK kinase activity and Y397 phosphorylation. Active FAK in turn accumulated in the nucleus where it led to the expression of osteopontin and other FN-type matrix in both mouse embryonic fibroblasts and human melanoma. Our data support a model in which FAK Y397 autophosphorylation is required for FAK function in vivo and is positively regulated by MYO1E.

The aim of this work was to investigate the mechanisms of cytotoxicity of phyto-hydroxyanthraquinone aloe-emodin (AE) on human brain microvascular endothelial cell line hCMEC/D3 and to assess the cellular response in the early stage of treatment in order to extend the knowledge of AE’s anti-angiogenic properties. The immortalized human brain capillary endothelial cells hCMEC/D3 were treated with a series of AE concentrations (5 - 200 μM) for a period of 24 hours. The cell viability was determined by MTS assay. The cellular adenosine triphosphate (ATP) levels were evaluated by CellTiter-Glo® luminescent assay. The intracellular reactive oxygen species (ROS) were determined by 2’,7’-dichlorofluorescein (CM- H2DCFDA) fluorescence assay. The mitochondrial membrane potential (MMP) was assessed using tetramethylrhodamine methyl ester (TMRM) staining, while Fluo-4 was used to measure 2 the intracellular free Ca 2+ concentrations inside living cells analysed by High Content Analysis using the Arrayscan VTI 740. Twenty-four- hour treatment of hCMEC/D3 cells with AE, in concentrations between 50 and 200 µM, decreased the cell viability as well as the intracellular ATP levels in a dose- dependent manner. Increased ROS production and disruption of the mitochondrial membrane potential have also been detected. Notably, AE at a concentration greater than 5 µM dramatically increased intracellular calcium levels. Our results collectively indicate that AE inhibits proliferation of human brain microvascular cells via a mechanism involving ROS generation, disruption of Ca 2+ homeostasis and mitochondrial damage.

Rac1 is a Rho subfamily small GTPase which is highly expressed in epidermal keratinocytes. In mice the significance of Rac1 for the maintenance of the epidermis has been controversial. In keratinocytes from human origin, the role of Rac1 in the control of growth/differentiation is still obscure. In this study we used RNA interference to induce specific inhibition of Rac1 expression in cultured human keratinocytes and analyzed the consequences on proliferation and differentiation. We found that the autocrine proliferation of keratinocytes is unaltered by Rac1 silencing. However, the suppression of Rac1 induced premature differentiation as revealed by the expression of markers (keratin 10, involucrin), but the involved mechanism is independent of the activity of p38 mitogen-activated protein kinase. Rather, we found that the effects of Rac1 silencing on keratinocytes differentiation are concomitant with negative regulation of the Ser62/Thr58 phosphorylation on the transcription factor c-myc, a mechanism known to control post-translational stability of the c-myc protein. Thus, in growing human keratinocytes, Rac1 could impede the expression of premature differentiation markers, probably by exerting positive control on c-myc activity and its binding to specific promoters.

We have developed a novel biological system for quantitative analysis of biochemical pathways in normal and tumour human cells. The system is based on cells growing in tissue culture media where the concentrations of growth factors, hormones and other components of the media are precisely defined and continuously monitored. Quantitative immunoblotting and luminescence-based reporter assays are then used to measure the cellular concentration of key cell cycle regulatory proteins and their activity in real time in live cells. This technology resulted in accurate measurement of cellular concentration of a number of key cell cycle regulatory proteins such as Cyclins, CDKs and CDK inhibitors during the cell cycle. The data are being utilized in the development of a quantitative integrated systems biology approach to the cell cycle. The approach consists of a comprehensive network of the molecular interaction pathways regulating cell cycle in normal and tumor cells and a model which incorporates the activity of key molecular species in a single dynamical system which can be solved using genetic algorithms designed to match experimental data, both qualitative and quantitative, to the model kinetics. The model could be utilized for the development of new drug targets and would be capable of consistently measuring the effects of existing drugs (either single or in combination) and opens up a methodology for establishing the effectiveness of these drugs with clear implications for cost/benefit assessment. Major impact is expected on clinical research where the model can be a tool in determining intervention strategies in the molecular pathways concerned. Apart from the development of new drug targets the model will be capable of consistently measuring the effects of existing drugs (either single or in combination) and opens up a methodology for establishing the effectiveness of anti-cancer drugs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4913. doi:1538-7445.AM2012-4913

Младежкият социолект е тема, която в не малка степен е подценявана от науката най-вече поради нецензурната лексика, която е една от характеристиките на младежкото общуване. Всъщност, както вулгарният език на младежкия сленг, така и „по-интелигентната“ му сфера – в лицето на студентското арго, представляват изключително интересна и богата тема от гледна точка на особеностите, които младежкият сленг проявява в областите на семантиката, морфологията и прагматиката. Мостовете между жаргона и официалния език представляват средство за комуникация между различните социални групи. Настоящата разработка доказва, че именно младежкият сленг, въпреки своята вулгарност, представлява необходимия комуникативен мост и иновационен фактор в езика, липсващото звено, свързващо социолектите помежду им с националния жаргон и език. Чрез социалните диалекти и особено чрез младежкия жаргон ние изразяваме най-вече своите мисли, чувства и емоции по начин, по който националният език е неспособен да извърши това. Младежкият жаргон е неразделна част от нашето ежедневие и ние сме заобиколени от жаргона във всяка комуникационна среда. Целта на настоящото езиково проучване е да изясни защо (чрез прагматичен и психолингвистичен анализ) и как (чрез лексикален, семантичен и морфологичен анализ) този феномен се появява в българския и в гръцкия младежки жаргон. На базата на проведените лексикалните анализи откриваме, че много думи от различни социални диалекти (анализирани подробно в главата, посветена на аргото The youth sociolect is a topic that is greatly underestimated by science mainly due to obscene speech, which is one of the characteristics of youth communication. In fact, both the vulgar language of youth slang and its "smarter" aspect – in the face of student slang are extremely interesting and rich in terms of the fields of semantics, morphology and pragmatics of the youth sociolect. The bridges between jargon and the official language are a means of communication between different social groups. The present study proves that youth slang, despite its vulgarity, is the necessary communicative bridge and innovative factor in the language, the missing link connecting the sociolects between them with the national slang and language. Through the social dialects and especially through the youth jargon, we mostly express our thoughts, feelings and emotions in a way that the national language is unable to do so. The youth jargon is an integral part of our daily lives and we are surrounded by jargon in every communication environment. The aim of the present linuistic study is to clarify why (through pragmatic and psycholinguistic analysis) and how (through lexical, semantic and morphological analysis) the phenomenon of the youth slang appears in Bulgarian and Greek jargon. Based on the lexical analyzes, we find that many words from different social dialects (analyzed in detail in the chapter on argot) enter the language in the same way and through identical sources (argot, dialects