Лиганды сигнальных белков Ерас как инструменты для изучения их биологической активности и создания новых оригинальных лекарственных средств

The review discusses modern views about the structure and functions of Epac proteins (exchange proteins directly activated by cyclic adenosine monophosphate). The involvement of Epac proteins both in the regulation of the physiological functions of the body and in the initiation of various pathological processes allows to consider them as a fundamentally new biological target for creating original, highly effective drugs. Information on existing Epac protein agonists and antagonists was collected, and the influence of Epac ligands structure on the values of their affinity and selectivity was analyzed. Presumptive mechanisms of the interaction of ligands with Epac proteins are presented.В обзоре рассмотрены современные представления о строении и функциях белков Ерас (exchange proteins directly activated by cAMP, обменные белки, напрямую активируемые циклическим аденозинмонофосфатом). Вовлечённость белков Ерас как в регуляцию физиологических функций организма, так и в инициации различных патологических процессов позволяет рассматривать их как принципиально новую биомишень для создания оригинальных, высокоэффективных лекарственных средств. Собраны сведения о существующих агонистах и антагонистах белков Ерас, проанализировано влияние строения лигандов Ерас на значения их аффинности и селективности. Представлены предполагаемые механизмы взаимодействия лигандов с белками Ерас

DNA topoisomerases participate in fragility of the oncogene RET

Fragile site breakage was previously shown to result in rearrangement of the RET oncogene, resembling the rearrangements found in thyroid cancer. Common fragile sites are specific regions of the genome with a high susceptibility to DNA breakage under conditions that partially inhibit DNA replication, and often coincide with genes deleted, amplified, or rearranged in cancer. While a substantial amount of work has been performed investigating DNA repair and cell cycle checkpoint proteins vital for maintaining stability at fragile sites, little is known about the initial events leading to DNA breakage at these sites. The purpose of this study was to investigate these initial events through the detection of aphidicolin (APH)-induced DNA breakage within the RET oncogene, in which 144 APHinduced DNA breakpoints were mapped on the nucleotide level in human thyroid cells within intron 11 of RET, the breakpoint cluster region found in patients. These breakpoints were located at or near DNA topoisomerase I and/or II predicted cleavage sites, as well as at DNA secondary structural features recognized and preferentially cleaved by DNA topoisomerases I and II. Co-treatment of thyroid cells with APH and the topoisomerase catalytic inhibitors, betulinic acid and merbarone, significantly decreased APH-induced fragile site breakage within RET intron 11 and within the common fragile site FRA3B. These data demonstrate that DNA topoisomerases I and II are involved in initiating APH-induced common fragile site breakage at RET, and may engage the recognition of DNA secondary structures formed during perturbed DNA replication

Absence of a specific radiation signature in post-Chernobyl thyroid cancers

Thyroid cancers have been the main medical consequence of the Chernobyl accident. On the basis of their pathological features and of the fact that a large proportion of them demonstrate RET-PTC translocations, these cancers are considered as similar to classical sporadic papillary carcinomas, although molecular alterations differ between both tumours. We analysed gene expression in post-Chernobyl cancers, sporadic papillary carcinomas and compared to autonomous adenomas used as controls. Unsupervised clustering of these data did not distinguish between the cancers, but separates both cancers from adenomas. No gene signature separating sporadic from post-Chernobyl PTC (chPTC) could be found using supervised and unsupervised classification methods although such a signature is demonstrated for cancers and adenomas. Furthermore, we demonstrate that pooled RNA from sporadic and chPTC are as strongly correlated as two independent sporadic PTC pools, one from Europe, one from the US involving patients not exposed to Chernobyl radiations. This result relies on cDNA and Affymetrix microarrays. Thus, platform-specific artifacts are controlled for. Our findings suggest the absence of a radiation fingerprint in the chPTC and support the concept that post-Chernobyl cancer data, for which the cancer-causing event and its date are known, are a unique source of information to study naturally occurring papillary carcinomas

Повреждение легких, ассоциированное с вейпингом и электронными сигаретами

This literature review presents data from 57 publications on vaping and e-cigarette-associated lung injury or EVALI (e-cigarette or vaping use-associated lung injury) that was first reported in 2019. The article describes the epidemiology of EVALI, the mechanism of injuring effects of vaping on the lungs, clinical signs, diagnosis and diagnostic criteria, therapy and subsequent management of patients with EVALI.В обзоре литературы представлены данные из 57 источников литературы о повреждении легких, ассоциированном с вейпингом и электронными сигаретами (ПЛАВЭС), или EVALI (e-cigarette, or vaping, product use associated lung injury), которое описано в 2019 г. Приведены сведения об эпидемиологии ПЛАВЭС, дано описание механизма повреждающего воздействия вейпинга на легкие, клинической картины, диагностики и диагностических критериев, терапии и последующего ведения пациентов с ПЛАВЭС

Targeting BRAF in thyroid cancer

Activating mutations in the gene encoding BRAF are the most commonly identified oncogenic abnormalities in papillary thyroid cancer. In vitro and in vivo models have demonstrated that overexpression of activated BRAF induces malignant transformation and aggressive tumour behaviour. BRAF and other RAF kinases are frequently activated by other thyroid oncogenes and are important mediators of their biological effects including dedifferentiation and proliferation. Because current therapeutic options for patients with thyroid cancers that are aggressive and/or do not respond to standard therapies are limited, BRAF and its downstream effectors represent attractive therapeutic targets. In this review, data supporting a role for BRAF activation in thyroid cancer development and establishing the potential therapeutic efficacy of BRAF-targeted agents in patients with thyroid cancer will be reviewed

Stability of Metabolic Correlations under Changing Environmental Conditions in Escherichia coli – A Systems Approach

Background: Biological systems adapt to changing environments by reorganizing their cellular and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underlying metabolic network. Methodology/Principal Findings: Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic condition-dependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple observations about the changes of metabolic concentrations. The approach was tested with Escherichia coli as a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diauxie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical pathways, and (3) independently of the response scale, based on their importance in the reorganization of the correlation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response. Conclusions/Significance: Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-based approach does not rely on major changes in concentration to identify metabolites important for stress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches