О НОВЫХ ДИАГНОСТИЧЕСКИХ ВОЗМОЖНОСТЯХ CD138 (СИНДЕКАНА-1) ПРИ МНОЖЕСТВЕННОЙ МИЕЛОМЕ

Syndecan-1 (CD138) is one of the main cell markers used in flow cytometric analysis of multiple myeloma (MM) cells. CD138 and several other markers – CD19, CD45, CD56 – which are often used in order to characterize MM and give the possibility to differentiate MM cells from the normal plasmocytes are described. Only CD138-expressing MM plasma cells are usually taken into account in MM analysis. The current literature data point out that CD138-negative MM plasma cells could be important for MM prognosis, as well. This cell population demonstrates certain properties that are typical to the cancer stem cells. CD138-negative cell population is characterized by higher proliferation, clonogenicity, engraftment in immunodeficient mice as compared to CD138 expressing plasma cells. Besides that, CD138-negative cells were more resistant than CD138-positive cells to the drugs that are used in MM chemotherapy. CD138-negative plasma cells are able to produce CD138 expressing cells upon a long-term culture in vitro and thus to reproduce the heterogenic in CD138 expression population of MM plasma cells. The results of these investigations, as well as statistical data indicating the worse overall survival of CD138 low expressing MM patients point out that CD138-negative population of MM plasma cells should be taken into consideration in MM analysis. Thus, it could be important to find the new markers distinguishing the plasma cell population differing in CD138 expression. Vascular endothelial growth factor receptor VEGFR3 was found to be a new marker with such properties.Синдекан-1, или CD138, – один из основных маркеров, используемых при проточно-цитометрическом анализе плазматических клеток множественной миеломы (ММ). В обзоре приводятся сведения о CD138, а также о некоторых других часто применяемых для характеристики ММ маркерах – CD19, CD45, CD56, позволяющих отличать клетки ММ от нормальных плазмоцитов. При анализе ММ, как правило, учитывается только популяция плазмоцитов, экспрессирующая маркер CD138. Известные в настоящее время из литературы данные свидетельствуют о том, что популяция плазматических клеток миеломы, не экспрессирующих CD138 (CD138 –), не менее важна для оценки прогноза ММ. Эта популяция плазмоцитов проявляет некоторые свойства, которыми должны обладать стволовые опухолевые клетки. В популяции CD138 – клеток повышены индекс пролиферации, клоногенность, прививаемость иммунодефицитным мышам по сравнению с плазмоцитами, положительными по экспрессии этого маркера. Кроме того, негативные по экспрессии CD138 клетки оказались более устойчивы к действию ряда применяемых при лечении ММ химиопрепаратов, чем клетки, экспрессирующие этот маркер. Плазматические CD138 – клетки при культивировании in vitro способны продуцировать плазматические CD138+ клетки и таким образом воспроизводить гетерогенную по экспрессии CD138 популяцию клеток миеломы. Результаты проведенных исследований, а также статистические данные, указывающие на худшую выживаемость больных ММ со сниженным уровнем экспрессии CD138, свидетельствуют о необходимости учета популяции CD138 – плазмоцитов при анализе этого заболевания. Поэтому представляется важной задача поиска новых маркеров, позволяющих различать экспрессирующие CD138 популяции плазматических клеток ММ и плазмоциты, не экспрессирующие этот маркер. Одним из таких маркеров оказался рецептор фактора роста эндотелия сосудов VEGFR3

Germline-restricted chromosome (GRC) is widespread among songbirds

An unusual supernumerary chromosome has been reported for two related avian species, the zebra and Bengalese finches. This large, germline-restricted chromosome (GRC) is eliminated from somatic cells and spermatids and transmitted via oocytes only. Its origin, distribution among avian lineages, and function were mostly unknown so far. Using immunolocalization of key meiotic proteins, we found that GRCs of varying size and genetic content are present in all 16 songbird species investigated and absent from germline genomes of all eight examined bird species from other avian orders. Results of fluorescent in situ hybridization of microdissected GRC probes and their sequencing indicate that GRCs show little homology between songbird species and contain a variety of repetitive elements and unique sequences with paralogs in the somatic genome. Our data suggest that the GRC evolved in the common ancestor of all songbirds and underwent significant changes in the extant descendant lineages

Значение предсуществующей лекарственной устойчивости, обусловленной гиперэкспрессией Р-гликопротеина, для формирования резистентности к бортезомибу

Objective of the study. In our work we investigated the effect of pre-existing drug resistance by the mechanism of activation of ABC transporters – P-glycoprotein (Pgp) overexpression – on the development of resistance to the proteasome inhibitor bortezomib.Materials and methods. Cultures RPMI8226 and K562 / i-S9 (with Pgp overexpression) and their bortezomib-resistant sublines RPMI8226 / btz-6 and K562 / i-S9vlc were used as models. The methods used were MTT test, flow cytometry, Western blot and real-time polymerase chain reaction using the Human Signal Transduction Pathway Finder system.Results. The expression of the main PI3K-AKT and NF-κB signaling pathways did not change in RPMI8226 / btz-6 subline cells. However, AKT kinase expression was significantly increased and PTEN protein expression was reduced in K562 / i-S9vlc cells with Pgp-overexpression. Significant changes in gene expression (42 %) were found in RPMI8226 / btz-6 cells related to a number of main signaling pathways in the tumor cell, namely: activation of 3–4 genes in signaling pathways related to hypoxia, oxidative stress, PPAR and p53. The highest activation in these cells was found in the TGFβ signaling pathway. In resistant K562 / i-S9vlc cells, expression of only 5 genes (10 %) increased: Fas, HMOX1, CPT2, ICAM, and SOCS3. Three genes were also identified that changed in both resistant sublines: Fas, HMOX1 and CPT2. Further, we showed that in the RPMI8226 / btz-6 subline, along with changes in the expression of signal transduction genes, there is a large pool of CD138-negative cells, and in the K562 / i-S9vlc subline, the number of cells expressing CD34 increases and the number of CD13 decreases.Conclusion. We found that different signaling pathways are involved in the formation of resistance to bortezomib in the absence of Pgp expression and its overexpression. In addition, a cell line without activated resistance pathways requires more extensive rearrangements in the signal system to acquire resistance to bortezomib. However, in both cases, bortezomib leads to a change in the immunophenotype of the cells – to the appearance of dedifferentiated subpopulations.Цель исследования – изучить влияние предсуществующей лекарственной устойчивости по механизму активации АВС-транспортеров – гиперэкспрессии Р-гликопротеина (Pgp) – на пути развития резистентности к протеасомному ингибитору бортезомибу.Материалы и методы. В качестве моделей использовали культуры RPMI8226 и K562 / i-S9 (с гиперэкспрессией Pgp) и их резистентные к бортезомибу сублинии RPMI8226 / btz-6 и K562 / i-S9vlc. Применяли методы МТТ-теста, проточной цитометрии, вестерн-блоттинга и полимеразной цепной реакции в реальном времени с использованием системы Human Signal Transduction Pathway Finder.Результаты. В клетках сублинии RPMI8226 / btz-6 не изменялась экспрессия основных белков PI3K-AKT и NF-κB-сигнальных путей. Однако в клетках сублинии K562 / i-S9vlc с гиперэкспрессией Pgp значительно повышалась экспрессия AKT-киназы и снижалась экспрессия белка PTEN. В клетках сублинии RPMI8226 / btz-6 были найдены значительные изменения в экспрессии генов (42 %), относящихся к ряду основных сигнальных путей в опухолевой клетке, а именно активация 3–4 генов в сигнальных путях, отно сящихся к гипоксии, оксидативному стрессу, PPAR и p53. Наибольшая активация в этих клетках обнаружена в TGFβ-сигнальном пути. В устойчивых клетках K562 / i-S9vlc усилилась экспрессия только 5 генов (10 %): Fas, HMOX1, CPT2, ICAM и SOCS3. Также были выделены 3 гена, экспрессия которых изменилась в обеих устойчивых сублиниях: Fas, HMOX1 и CPT2. Далее мы показали, что в сублинии RPMI8226 / btz-6, наряду с изменениями экспрессии генов сигнальной трансдукции, присутствует большой пул CD138-негативных клеток, а в сублинии K562 / i-S9vlc повышается количество клеток, экспрессирующих СD34, и снижается количество CD13.Заключение. Мы выявили, что в формировании устойчивости к бортезомибу в клетках с отсутствием экспрессии Pgp и в клетках с гиперэкспрессией этого белка задействованы разные сигнальные пути. Кроме этого, клеточной линии без активированных путей устойчивости необходимы более масштабные перестройки в сигнальной системе для приобретения резистентности к бортезомибу. Однако и в том и в другом случае бортезомиб приводит к изменению иммунофенотипа клеток – к появлению дедифференцированных субпопуляций

The origin of B chromosomes in yellow-necked mice (Apodemus flavicollis)—Break rules but keep playing the game

B chromosomes (Bs) are known for more than hundred years but their origin, structure and pattern of evolution are not well understood. In the past few years new methodological approaches, involving isolation of Bs followed by whole DNA amplification, DNA probe generation, and fluorescent in situ hybridization (FISH) or the B chromosome DNA sequencing, has allowed detailed analysis of their origin and molecular structure in different species. In this study we explored the origin of Bs in the yellow-necked wood mouse, Apodemus flavicollis, using generation of microdissected DNA probes followed by FISH on metaphase chromosomes. Bs of A. flavicollis were successfully isolated and DNA was used as the template for B-specific probes for the first time. We revealed homology of DNA derived from the analyzed B chromosomes to the pericentromeric region (PR) of sex chromosomes and subtelomeric region of two pairs of small autosomes, but lower homology to the rest of the Y chromosome. Moreover, all analysed Bs had the same structure regardless of their number per individual or the great geographic distance between examined populations from the Balkan Peninsula (Serbia) and Eastern Europe (south region of Russia and central Belarus). Therefore, it was suggested that B chromosomes in A. flavicollis have a unique common origin from the PR of sex chromosomes, and/or similar evolutionary pattern.PloS one (2017), 12(3): e017270

Low-pass single-chromosome sequencing of human small supernumerary marker chromosomes (sSMCs) and Apodemus B chromosomes.

Supernumerary chromosomes sporadically arise in many eukaryotic species as a result of genomic rearrangements. If present in a substantial part of species population, those are called B chromosomes, or Bs. This is the case for 70 mammalian species, most of which are rodents. In humans, the most common types of extra chromosomes, sSMCs (small supernumerary marker chromosomes), are diagnosed in approximately 1 of 2000 postnatal cases. Due to low frequency in population, human sSMCs are not considered B chromosomes. Genetic content of both B-chromosomes and sSMCs in most cases remains understudied. Here, we apply microdissection of single chromosomes with subsequent low-pass sequencing on Ion Torrent PGM and Illumina MiSeq to identify unique and repetitive DNA sequences present in a single human sSMC and several B chromosomes in mice Apodemus flavicollis and Apodemus peninsulae. The pipeline for sequencing data analysis was made available in Galaxy interface as an addition to previously published command-line version. Human sSMC was attributed to the proximal part of chromosome 15 long arm, and breakpoints leading to its formation were located into satellite DNA arrays. Genetic content of Apodemus B chromosomes was species-specific, and minor alterations were observed in both species. Common features of Bs in these Apodemus species were satellite DNA and ERV enrichment, as well as the presence of the vaccinia-related kinase gene Vrk1. Understanding of the non-essential genome elements content provides important insights into genome evolution in general.This is a post-peer-review, pre-copyedit version of an article published in Chromosoma. The final authenticated version is available online at: [http://dx.doi.org/10.1007/s00412-018-0662-0

Exploring and challenging the network of angiogenesis

Angiogenesis is one of the hallmarks of cancer and, as such, one of the alternative general targets for anticancer therapy. Since angiogenesis is a complex process involving a high number of interconnected components, a network approach would be a convenient systemic way to analyse responses to directed drug attacks. Herein we show that, although the angiogenic network is easily broken by short combinations of directed attacks, it still remains essentially functional by keeping the global patterns and local efficiency essentially unaltered after these attacks. This is a clear sign of its high robustness and resilience and stresses the need of directed, combined attacks for an effective blockade of the process. The results of this theoretical study could be relevant for the design of new antiangiogenic therapies and the selection of their targets

Genes flanking Xist in mouse and human are separated on the X chromosome in American marsupials

X inactivation, the transcriptional silencing of one of the two X chromosomes in female mammals, achieves dosage compensation of X-linked genes relative to XY males. In eutherian mammals X inactivation is regulated by the X-inactive specific transcript (Xist), a cis-acting non-coding RNA that triggers silencing of the chromosome from which it is transcribed. Marsupial mammals also undergo X inactivation but the mechanism is relatively poorly understood. We set out to analyse the X chromosome in Monodelphis domestica and Didelphis virginiana, focusing on characterizing the interval defined by the Chic1 and Slc16a2 genes that in eutherians flank the Xist locus. The synteny of this region is retained on chicken chromosome 4 where other loci belonging to the evolutionarily ancient stratum of the human X chromosome, the so-called X conserved region (XCR), are also located. We show that in both M. domestica and D. virginiana an evolutionary breakpoint has separated the Chic1 and Slc16a2 loci. Detailed analysis of opossum genomic sequences revealed linkage of Chic1 with the Lnx3 gene, recently proposed to be the evolutionary precursor of Xist, and Fip1, the evolutionary precursor of Tsx, a gene located immediately downstream of Xist in eutherians. We discuss these findings in relation to the evolution of Xist and X inactivation in mammals

Low-Dosage Inhibition of DII4 Signaling Promotes Wound Healing by Inducing Functional Neo-Angiogenesis

Recent findings regarding Dll4 function in physiological and pathological conditions indicate that this Notch ligand may constitute an important therapeutic target. Dll4 appears to be a major anti-angiogenic agent, occupying a central role in various angiogenic pathways. The first trials of anti-Dll4 therapy in mice demonstrated a paradoxical effect, as it reduced tumor perfusion and growth despite leading to an increase in vascular density. This is seen as the result of insufficient maturation of the newly formed vasculature causing a circulatory defect and increased tumor hypoxia. As Dll4 function is known to be closely dependent on expression levels, we envisioned that the therapeutic anti-Dll4 dosage could be modulated to result in the increase of adequately functional blood vessels. This would be useful in conditions where vascular function is a limiting factor for recovery, like wound healing and tissue hypoxia, especially in diabetic patients. Our experimental results in mice confirmed this possibility, revealing that low dosage inhibition of Dll4/Notch signaling causes improved vascular function and accelerated wound healing