Arc/Arg3.1 expression in the brain tissues during the learning process in Alzheimer's disease animal models

Introduction. Arc/Arg3.1 is a common marker of neuronal activation for learning and memorizing. Some experimental data show the Arc/Arg3.1 expression in the post-mitotic neurons of the neurogenic niches. At the same time, we still have to understand the importance of such an expression for neurogenesis induced by the learning or memorizing processes, in health and in disease. Objective: to evaluate the changes in Arc/Arg3.1 expression in the post-mitotic neurons and to assess the proliferative activity of the neurogenic niche cells in Alzheimer's disease animal models. Materials and methods. We divided the C57Bl/6В mice into 2 groups: experimental (n = 15) and control (n = 15). The experimental group were injected with the amyloid- oligomers 2535 in their CA1 hippocampal region while the control mice received normal saline injections in the same region. Passive Avoidance Test (PAT) was used to assess the cognitive functions from the day 9 after the intervention. One hour after each test session we collected the samples of brain tissues to immunohistochemically assess them for the Arc/Arg3.1 expression and PCNA cell proliferation marker. Results. At day 11 the count of Arc/Arg3.1+NeuN+ cells in the subgranular zone had significantly increased. In animal neurodegeneration models the 1st and 2nd PAT sessions were associated with a significant increase in Arc/Arg3.1+NeuN+ cells, although by the day 11 their count significantly decreased. The count of Arc/Arg3.1+ cells in the subventricular and subgranular zones had increased after the 3rd PAT session in the control group while in Alzheimer's disease animal models this was observed only after the 2nd PAT session. Preserved Arc/Arg3.1 expression in the subventricular zone is associated with the increased PCNA cell prolifera- tion marker expression. At the same time, the toxic effect of the amyloid- oligomers suppressed the cells' proliferative activity in the subgranular zone at day 9. Conclusions. Despite the toxic effect of the amyloid- oligomers 2535, the post-mitotic neurons of the neurogenic niches retained the ability to express Arc/Arg3.1 in vivo. The obtained results show a transient increase in sensitivity of the post-mitotic neurons of the neurogenic niches for the learning stimuli in the early stages of the Alzheimer-type neurodegeneration

ТРАНСКРИПТОМНЫЙ АНАЛИЗ КЛЕТОК МЕЛАНОМЫ, ПОЛУЧЕННЫХ ИЗ РАЗЛИЧНЫХ УЧАСТКОВ ПЕРВИЧНОЙ ОПУХОЛИ

Introduction. Intratumor heterogeneity is a characteristic feature for most malignant tumors, including cutaneous melanoma. This property represents one of the main obstacles  for effective targeted therapy, due to the different sensitivity to chemotherapeutic agents on  various tumor cells subclones. Treatment of malignant tumors requires an individual approach to choose the most appropriate treatment regimen.The purpose of the study was to evaluate differences in melanoma tissue samples obtained from different parts of one patient’s primary tumor at the transcriptomic level.Material and Methods. Melanoma cell cultures obtained from both central and peripheral parts of the primary tumor of two patients were used in the study.Results. Subclones from different parts of the first patient’s tumor were similar, whereas the second patient demonstrated significant differences at the transcriptomic level (in 2953  transcripts out of 48226). In the cells of the central zone of the second patient’s tumor, an  increase in mRNA of the genes encoding proteins associated with tumor-specific immune  response, as well as ABC-family transport proteins and cytokine signaling molecules, were  noted. In the cells from the peripheral area of the same tumor, a more intensive transcription of genes encoding extracellular matrix and inflammatory response  proteins was observed. Taken all round, the differences between the subclones of the second  patient’s cells were relevant to some signaling cascades playing a leading role in  oncogenesis (MAPK, PI3K-Akt-mTOR, VEGFA-VEGFR2, etc.).Conclusion. The study allowed  evaluation of differences between cancer cells within a tumor at the transcriptional level in order to search for further approaches to personalized melanoma therapy.Введение. Внутриопухолевая гетерогенность представляет собой характерную черту большинства злокачественных новообразований, в том числе и меланомы кожи. Данное свойство является  одним из препятствий для проведения эффективной таргетной терапии, поскольку у различных субклонов опухолевых клеток наблюдается вариабельная чувствительность к данным препаратам. С  современных позиций терапия злокачественных новообразований требует персонифицированного подхода  для каждого конкретного пациента.Цель исследования – оценка возможных различий между тканями меланомы, выделенными из различных участков первичной опухоли одного пациента на транскриптомном уровне.Материал и методы. В работе были использованы культуры клеток меланомы, полученные из центральной и периферической частей первичной опухоли двух пациентов. Исследование транскриптомов клеток  проводили методом микрочипирования с последующим биоинформатическим анализом.Результаты. В клетках меланомы первого пациента, полученных из центрального и периферического  участков одной опухоли, не было выявлено различий по транскриптомному профилю. У второго пациента  имели место существенные различия (по 2953 транскриптам из 48226). В клетках, полученных из  центрального участка опухоли, выявлено повышение мРНК генов, кодирующих белки, ассоциированные с  иммунным ответом опухоли, транспортные белки ABC‑семейства, сигнальные молекулы класса цитокинов. В  культуре клеток, выделенной из периферического участка этой же опухоли, зарегистрировано увеличение  уровня мРНК генов, кодирующих белки внеклеточного матрикса и воспалительного ответа. В целом  различия между субклонами клеток второго пациента касались ряда сигнальных каскадов, играющих  ведущую роль в онкогенезе (MAPK, PI3K-Akt-mTOR, VEGFAVEGFR2 и др). Заключение. Проведенное  исследование позволяет оценить возможные различия между клетками внутри опухоли на  транскрипционном уровне с целью поиска новых подходов для персонифицированной терапии

Оценка противоопухолевых, токсических эффектов и характера экспрессии генов-мишеней miR-204-5p при применении ее имитатора на модели меланомы В-16 in vivo

Objective. To evaluate anti-tumor, toxic effect of miR-204-5p mimic applicaton on melanoma B-16-bearing mice followed by miR-204-5p target gene expression estimation in melanoma tumor and distant organs. Material and Methods. C57Bl/6 melanoma B-16-bearing mice were used. The animals of the experimental group were intraperitoneally injected with a 5 nM miR-204-5p miRNA simulator (mimic) on the 8th, 10th, and 12th days after melanoma B-16 cell transplantation. Based on the results of bioinformatic analysis, miR-204-5p target genes BCL2 and SIRT1 expression levels were determined by quantitative real-time PCR. The toxic effect of miR-204-5p mimic was estimated by the evaluation of body weight, mass of the internal organs, and motor activity. Results. On the 13-14th days of the experiment, the motor activity of animals in the control groups decreased signifcantly compared to the group of animals treated by miR-204-5p. Target gene BCL2 showed increased expression in the lungs and kidneys and SIRT1 levels were increased in the lungs of miR-204-5p mimic treated animals (p˂0.05). Tumor mass tended to decrease in the animals treated by miR-204-5p mimic. Conclusion. Modulation of the level of miR-204-5p microRNA led to changes in the expression of SIRT1 and BCL2 in the lungs of animals, and changes in the expression of BCL2in the kidneys. MiR-204-5p mimic application did not have toxic effect on animals treated. Further studies are necessary to clarify miR-204-5p implication in melanoma cell proliferation regulation as well as it’s biodistibution in the tumor tissue.Цель исследования – оценка влияния имитатора miR-204-5p на рост меланомы В-16 in vivo при внутрибрюшинном трехкратном его введении, определение изменения при этом экспрессии генов-мишеней miR-204-5p в опухоли и дистантных органах, а также выраженности токсических реакций.Материал и методы. Исследование проводили на мышах C57Bl/6 с подкожно перевитой меланомой B-16. Животным опытной группы внутрибрюшинно вводили имитатор микроРНК miR-204-5p (5нМоль) на 8, 10, 12-е сут после трансплантации опухолевых клеток. Согласно результатам биоинформатического анализа определяли уровень экспрессии генов-мишеней микроРНК BCL2 и SIRT1 методом ПЦР в реальном времени. Определяли токсический эффект воздействия имитатора по динамике массы тела и органов, объему опухолевого узла, изменению двигательной активности и внешнего вида животных в течение эксперимента.Результаты. Оценка внешних признаков и динамики двигательной активности животных, а также динамики их массы и массы органов при вскрытии свидетельствует об отсутствии токсического эффекта имитатора miR-204-5p. К 13–14-му дню эксперимента двигательная активность в контрольных группах животных статистически значимо снизилась по сравнению с группой животных, которым вводился имитатор miR-204-5p (р=0,011) Отмечено повышение экспрессии BCL2 в легких и почках мышей и SIRT1 – в легких мышей (p˂0,05). Отмечалась тенденция к снижению массы опухолевого узла к 14-му дню эксперимента.Заключение. Модуляция уровня микроРНК miR-204-5p приводит к изменению экспрессии генов-мишеней – SIRT1 и BCL2 в легких животных, BCL2 – в почках. Введение имитатора микроРНК не вызывает нарушений двигательной активности животных, изменения массы внутренних органов, что может свидетельствовать об отсутствии развития токсического эффекта. Дальнейшее исследование требуется для разъяснения биодоступности модуляторов микроРНК в опухолевую ткань, а также влияния имитатора miR-204-5p на пролиферацию клеток меланомы in vivo

ПОВЫШЕНИЕ УРОВНЯ ЭКСПРЕССИИ miR-204-5P В КЛЕТКАХ МЕЛАНОМЫ ПОД ВОЗДЕЙСТВИЕМ ДАКАРБАЗИНА

Various types of tissues was analyzed, and the algorithm for summing neutron and photon doses in neutronMiRNA s are involved in the regulation of numerous critical biological processes, including cell proliferation, differentiation, migration and invasion. They function as oncogenes or tumor suppressors according to the nature of the target. It has been previously determined that miR-204-5p miRNA is characterized by the increased level in melanoma. The aim of this study was to determine the effects of changes in the level of microRNA expression when dacarbazine was exposed to melanoma cells in vitro and synthetic miR-204-5p in vivo. The expression levels of miR-204-5p and miR-211 in melanoma cells were determined by real-time PCR. Antitumor effects in vivo were verified in assessing the growth dynamics of the tumor node. Toxic effects were assessed by animal behavior, fluid intake, feed, and ALT , AST , creatinine, urea levels. In the model of melanoma C57BL6, it was revealed that the introduction of the synthetic miR-204-5p did not cause significant changes in the investigated microRNA in tumor cells. At the same time, the antitumor effects of dacarbazine in melanoma cells in vitro led to an increase in the level of the investigated microRNA by more than 20 times. The results of the study indicated the possibility of compensating the level of miR-204-5p under the influence of cytostatic therapy. Taking into account the previously revealed miR-204-5p inhibitory effect on the proliferation of melanoma cells, we can assume that this miRNA can play a role in maintaining the dermal state of tumor cells. Further studies are required to understand the metastasis development and predict the response to antitumor therapy for melanoma.МикроРНК участвуют в регуляции на эпигенетическом уровне многочисленных критических биологических процессов, включая клеточную пролиферацию, дифференцировку, миграцию и инвазию, функционируя в качестве онкосупрессоров или онкогенов. Ранее было определено, что микроРНК miR-204-5p характеризуется сниженным уровнем при меланоме. Основной целью данного исследования явилось определение эффектов изменения уровня экспрессии микроРНК при воздействии на клетки меланомы цитостатическим агентом дакарбазином in vitro, а также синтетическим аналогом miR-204-5p in vivo. Уровень экспрессии miR-204-5p и miR-211 в клетках меланомы оценивали с помощью ПЦР в реальном времени. Противоопухолевые эффекты in vivo определялись при оценке динамики роста опухолевого узла. Токсические эффекты оценивались по поведению животных, потреблению жидкости, корма, а также по уровню АЛТ, АСТ, креатинина, мочевины. На модели меланомы C57BL6 определено, что введение синтетического аналога miR-204-5p не вызвало значимых изменений исследуемой микроРНК в опухолевых клетках. Вместе с тем противоопухолевый препарат дакарбазин в клетках меланомы in vitro приводил к повышению уровня исследуемой микроРНК более чем в 20 раз. Полученные результаты исследования указывают на возможность восстановления уровня miR-204-5p под воздействием цитостатической терапии. С учетом выявленного нами ранее ингибирующего эффекта miR-204-5p на пролиферацию клеток меланомы стоит предположить, что данная микроРНК может играть роль в поддержании дормантного состояния опухолевых клеток. Полученные данные требуют дальнейшего разъяснения, так как это может иметь значение для понимания развития метастазирования, а также прогнозирования эффективности противоопухолевой терапии при меланоме

The combination of mutations in BRAF and NRAS genes within a one tumor in patients with cutaneous melanoma

The paper provides a clinical description and analysis of two melanoma cases with mutations in the BRAF and NRAS gene within one tumor. Until recently, it was believed that mutations in the BRAF and NRAS genes are exclusive and do not occur within the same tumor. Later it was revealed that these mutations can exist within one tumor, but this is still quite a rare phenomenon. Molecular genetic analysis of the tumor obtained from both patients showed a mutation in the 15 exon of the BRAF gene c.1799T>A (V600E) and exon 2 of the NRAS p.G13S gene (p.37 G>A). The expression level of non-mutant NRAS protein was different in both cases. In conclusion, so in one patient, despite the presence of a mutation in the NRAS gene, the level of expression of the non-mutant protein was absent, which can be related to possible posttranscriptional disorders in the regulation of gene expression

INCREASED LEVEL OF MIR-204-5P EXPRESSION IN MELANOMA CELLS UNDER THE INFLUENCE OF DACARBAZINE

Various types of tissues was analyzed, and the algorithm for summing neutron and photon doses in neutronMiRNA s are involved in the regulation of numerous critical biological processes, including cell proliferation, differentiation, migration and invasion. They function as oncogenes or tumor suppressors according to the nature of the target. It has been previously determined that miR-204-5p miRNA is characterized by the increased level in melanoma. The aim of this study was to determine the effects of changes in the level of microRNA expression when dacarbazine was exposed to melanoma cells in vitro and synthetic miR-204-5p in vivo. The expression levels of miR-204-5p and miR-211 in melanoma cells were determined by real-time PCR. Antitumor effects in vivo were verified in assessing the growth dynamics of the tumor node. Toxic effects were assessed by animal behavior, fluid intake, feed, and ALT , AST , creatinine, urea levels. In the model of melanoma C57BL6, it was revealed that the introduction of the synthetic miR-204-5p did not cause significant changes in the investigated microRNA in tumor cells. At the same time, the antitumor effects of dacarbazine in melanoma cells in vitro led to an increase in the level of the investigated microRNA by more than 20 times. The results of the study indicated the possibility of compensating the level of miR-204-5p under the influence of cytostatic therapy. Taking into account the previously revealed miR-204-5p inhibitory effect on the proliferation of melanoma cells, we can assume that this miRNA can play a role in maintaining the dermal state of tumor cells. Further studies are required to understand the metastasis development and predict the response to antitumor therapy for melanoma

TRANSCRIPTOMIC ANALYSIS OF MELANOMA CELLS EXTRACTED FROM DIFFERENT SITES OF THE PRIMARY TUMOR

Introduction. Intratumor heterogeneity is a characteristic feature for most malignant tumors, including cutaneous melanoma. This property represents one of the main obstacles  for effective targeted therapy, due to the different sensitivity to chemotherapeutic agents on  various tumor cells subclones. Treatment of malignant tumors requires an individual approach to choose the most appropriate treatment regimen.The purpose of the study was to evaluate differences in melanoma tissue samples obtained from different parts of one patient’s primary tumor at the transcriptomic level.Material and Methods. Melanoma cell cultures obtained from both central and peripheral parts of the primary tumor of two patients were used in the study.Results. Subclones from different parts of the first patient’s tumor were similar, whereas the second patient demonstrated significant differences at the transcriptomic level (in 2953  transcripts out of 48226). In the cells of the central zone of the second patient’s tumor, an  increase in mRNA of the genes encoding proteins associated with tumor-specific immune  response, as well as ABC-family transport proteins and cytokine signaling molecules, were  noted. In the cells from the peripheral area of the same tumor, a more intensive transcription of genes encoding extracellular matrix and inflammatory response  proteins was observed. Taken all round, the differences between the subclones of the second  patient’s cells were relevant to some signaling cascades playing a leading role in  oncogenesis (MAPK, PI3K-Akt-mTOR, VEGFA-VEGFR2, etc.).Conclusion. The study allowed  evaluation of differences between cancer cells within a tumor at the transcriptional level in order to search for further approaches to personalized melanoma therapy

The Role of microRNAs in Epigenetic Regulation of Signaling Pathways in Neurological Pathologies

In recent times, there has been a significant increase in researchers’ interest in the functions of microRNAs and the role of these molecules in the pathogenesis of many multifactorial diseases. This is related to the diagnostic and prognostic potential of microRNA expression levels as well as the prospects of using it in personalized targeted therapy. This review of the literature analyzes existing scientific data on the involvement of microRNAs in the molecular and cellular mechanisms underlying the development of pathologies such as Alzheimer’s disease, cerebral ischemia and reperfusion injury, and dysfunction of the blood–brain barrier

The Role of microRNAs in Epigenetic Regulation of Signaling Pathways in Neurological Pathologies

In recent times, there has been a significant increase in researchers’ interest in the functions of microRNAs and the role of these molecules in the pathogenesis of many multifactorial diseases. This is related to the diagnostic and prognostic potential of microRNA expression levels as well as the prospects of using it in personalized targeted therapy. This review of the literature analyzes existing scientific data on the involvement of microRNAs in the molecular and cellular mechanisms underlying the development of pathologies such as Alzheimer’s disease, cerebral ischemia and reperfusion injury, and dysfunction of the blood–brain barrier