Interaction between microRNA (miRNA) and messenger RNA of target genes at the posttranscriptional level provides fine-tuned dynamic regulation of cell signaling pathways. Each miRNA can be involved ...in regulating hundreds of protein-coding genes, and, conversely, a number of different miRNAs usually target a structural gene. Epigenetic gene inactivation associated with methylation of promoter CpG-islands is common to both protein-coding genes and miRNA genes. Here, data on functions of miRNAs in development of tumor-cell phenotype are reviewed. Genomic organization of promoter CpG-islands of the miRNA genes located in inter- and intragenic areas is discussed. The literature and our own results on frequency of CpG-island methylation in miRNA genes from tumors are summarized, and data regarding a link between such modification and changed activity of miRNA genes and, consequently, protein-coding target genes are presented. Moreover, the impact of miRNA gene methylation on key oncogenetic processes as well as affected signaling pathways is discussed.
The Numerical Advanced Model of Electron Cyclotron Resonance Ion Source (NAM-ECRIS) is applied for studies of the physical processes in the source. Solutions of separately operating electron and ion ...modules of NAM-ECRIS are matched in iterative ways such as to obtain the spatial distributions of the plasma density and of the plasma potential. Results reveal the complicated profiles with the maximized plasma density close to the ECR surface and on the source axis. The ion-trapping potential dips are calculated to be on the level of ∼(0.01-0.05) V being located at the plasma density maxima. The highly charged ions are also localized close to the ECR surface. The biased electrode effect is due to an 'electron string' along the source axis formed by reflection of electrons from the biased electrode and the extraction aperture. The string makes profiles of the highly charged ions more peaked on the source axis, thus increasing the extracted ion currents.
We analyzed changes in the level of methylation of CpG islands in four long non-coding RNA (lncRNA) genes
MEG3
,
ZNF667-AS1
,
GAS5
, and
SEMA3B-AS1
as promising markers of breast cancer. Methylation ...analysis was performed by quantitative methylation-specific PCR on a set of 38 paired (tumor/normal) breast cancer samples. Significantly (
p
<0.001) increased methylation was shown for three of the four lncRNA genes:
MEG3
,
ZNF667-AS1
, and
SEMA3B-AS1
. We found significant correlations of the methylation level of all the studied lncRNA genes with the stage of cancer and with lymphogenic metastasis, and for
MEG3
and
ZNF667-AS1
also with the tumor size. Methylation of
ZNF667-AS1
, and
SEMA3B-AS1
genes in breast cancer was detected for the first time. Based on these findings, new potential markers for the diagnosis and prognosis of breast cancer can be proposed.
We studied changes in the level of methylation of a number of microRNA genes hypermethylated in non-small cell lung cancer and its histological subtypes as well as the relationship of methylation of ...a group of microRNA genes with clinical and morphological features of the tumor with smoking status. A significantly high level of methylation of 7 genes (
MIR124-1/3
,
MIR125B-1
,
MIR129-2
,
MIR137
,
MIR1258
, and
MIR339
) was revealed in adenocarcinoma and squamous cell lung cancer in comparison with samples of adjacent histologically unchanged lung tissue. In squamous cell lung cancer, a significantly high level of methylation of the
MIR124-2
gene in the tumor was also shown. In addition, differences in the methylation profile of adenocarcinoma and squamous cell carcinoma at stages III-IV of the oncological process were revealed. A high level of methylation of the
MIR137
and
MIR1258
genes was shown for adenocarcinoma and
MIR339
,
MIR129-2
, and
MIR124-2
for squamous cell carcinoma. Significant differences in the level of methylation of
MIR124-2
and
MIR375
genes were revealed for smoking patients with squamous cell lung cancer.
Networks for data transmission between objects of V2X intelligent transport systems are currently being actively developed. Most existing V2X networks operate based on the IEEE 802.11p standard. ...However, these networks can only provide basic V2X applications and are unable to meet the demands of today’s applications. As a result, the IEEE committee began developing a new IEEE 802.11bd standard. A significant innovation of this standard is the use of the channel bonding method, which allows data to be transmitted in several channels at once. One of the approaches that can significantly increase the efficiency of the channel bonding method is the correct selection of the contention window. In this paper, we propose an adaptive algorithm for selecting a contention window that is compatible with the channel bonding method, is easy to implement, does not require changes to existing devices, and takes into account the requirements for the quality of service of various types of traffic. Using simulation it is shown that the proposed algorithm increases the maximal allowable density of stations, at which the requirements for quality of service are still met, by 25% compared to the standardized solution.
New Radio-Unlicensed (NR-U) is a technology that allows fifth generation mobile networks to utilize unlicensed frequency bands, in particular, the 5 GHz band. To increase throughput, an NR-U base ...station (gNB) can simultaneously operate in several frequency channels within the 5 GHz band. However, the gNB cannot always transmit data through one channel and, at the same time, perform the channel access procedure in another channel due to the out-of-band emission problem, which leads to channel underutilization. As a result, the throughput of NR-U networks can heavily depend on the out-of-band emission level. In this paper, by means of simulation, the impact of out-of-band emissions on NR-U performance is studied when NR-U uses all channel access methods defined in the specification. It is shown that the out-of-band emission level affects the choice of channel access method optimal in terms of throughput. We also show that out-of-band emissions do not always have a negative impact on NR-U performance; sometimes they make it possible to achieve more than 30% throughput gain.
We studied the correlations between the levels of methylation of a group of 21 microRNA genes in 99 primary tumors and 29 macroscopic peritoneal metastases of ovarian cancer. Analysis of the level of ...methylation by quantitative methylation-specific PCR showed that co-methylation was detected for 13 pairs of microRNA genes in primary tumors and for 22 pairs in metastases. Pairs of microRNA genes that have shown significant co-methylation can be involved in common processes and pathways of gene regulation and interaction and can have common target genes. The results are highly significant and pairs of microRNA genes can be proposed as new potential markers for the diagnosis and prognosis of ovarian cancer metastasis.
We studied the effect of functionally significant polymorphic markers of the
ESR1
gene on the risk of breast cancer, tamoxifen resistance, and survival of patients with this type of cancer. The study ...included 239 primary breast cancer patients without distant metastases. The analysis of genotype frequency distribution for the studied
ESR1
gene polymorphic markers showed the association of the
rs2228480
and
rs2234693
markers with tamoxifen resistance in the group of patients with luminal B type breast cancer. An association of these two polymorphic markers with the risk of tumor development was also revealed; for
rs2234693
polymorphic marker, a relationship with the survival of patients was also showed.
Abstract
Processes of the secondary electron emission (SEE) from the
walls are included into the Numerical Advanced Model of Electron
Cyclotron Resonance Ion Sources (NAM-ECRIS). It is found that SEE
...strongly influences electron confinement time and ion
production. With the modified model, we observe reactions of the
source to changes in a gas flow into the source and in an injected
microwave power. The source performance with scaling the hexapole
magnetic field is investigated. The calculated tendencies are close
to the experimental observations.
Systemic analysis of the relationship between the levels of methylation of 21 microRNA genes and the parameters of breast cancer progression was performed on a representative sample of 91 paired ...specimens of breast cancer and histologically normal tissues and a system of markers for prediction of metastasis was proposed. A significant association of hypermethylation of 11 genes with late (III-IV) clinical stages was found, and for 6 genes (
MIR124-1
,
MIR127
,
MIR34B/C
,
MIR9-3
,
MIR1258
, and
MIR339
) this association was highly significant (
p
≤0.001, FDR=0.01). For
MIR9-3
and
MIR339
, an association with tumor size was demonstrated (
p
<0.001, FDR=0.01). No association of the levels of methylation of the analyzed microRNA genes with the degree of differentiation were found. An association with lymph node metastasis was established for 9 microRNA genes; the most significant association was shown for 6 genes
MIR125B-1
,
MIR127
,
MIR9-3
,
MIR339
,
MIR124-3
, and
MIR1258
(
p
<0.005, FDR=0.05). Based on these 6 genes, a marker system for predicting breast cancer metastasis was developed by ROC analysis. This system is characterized by 87% sensitivity and 77% specificity (AUC=0.894). The proposed system may have clinical application in the personalized treatment of breast cancer patients.
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