دکتر بهرام محمد سلطانی

The activity of Wnt signaling pathway is increased in colorectal cancer. For this reason, finding new positive and negative regulators for this pathway is a treatment and diagnostic strategy of colorectal cancer. Our bioinformatics analysis indicated that hsa-miR-424 (miR-424) could be a possible regulator of the Wnt signaling pathway. Accordingly, the expression level of miR-424 in colorectal cancer tissues was elevated compared with normal pairs and the results of RT-qPCR showed a significant increase in miR-424 expression (p < 0.01). Then, molecular analyzes using Top/Fop Flash and RT-qPCR techniques indicated that miR-424 overexpression leads to increased Wnt pathway activity in the SW480 cell line. In addition, the small molecules IWP-2 and PNU-74654 were used to inhibit the Wnt signaling pathway, and the miR-424 overexpression suggested that exert its effect on the level of β-catenin complex degradation. Then, dual-luciferase assay validated the interaction between miR-424 and APC. Overall, our results suggest miR-424 is a positive regulator of the Wnt signaling pathway, and it could be a possible prognosis for colorectal cancer.

Cardiovascular diseases (CVDs) are globally the number 1 cause of death. Despite improvement in treatment strategies, heart disorders are strongly increasing. Therefore, identification of new regulatory factors involved in the cardiac differentiation is very important. TRKC receptor, part of the large family of receptor tyrosine kinases, is involved in development of the heart and central nervous system. There are many contradictory functions related to the TRKC gene which might be attributed to the non-coding RNAs located in it. Recently, a novel miRNA, hsa-miR-11181-5p located in TRKC gene, has been reported which is involved in nervous differentiation. MiRNAs are small non-coding RNAs regulating their target genes via mRNA degradation or protein inhibition. The goal of the present study was to investigate the expression pattern of hsa-miR-11181-5p during the course of cardiosphere-derived cells (CDCs) differentiation.

Breast cancer is the leading cause of cancer-related mortality among women worldwide. In Iran, breast cancer ranks first among cancers diagnosed in women comprising 24.4% of all malignancies. Currently, the large number of etiological factors and the complexity of breast cancer present challenge for prevention and treatment. Breast cancer tumorigenesis can be described as a multi-step process in which a normal cell undergoes malignant transformation to a fully developed tumor through accumulations of genetic and epigenetic changes. On the other hand, several studies indicated the signaling pathways role in Breast cancer. EGFR gene has been shown to be overexpressed in breast cancer. Dimerization of EGFR/HER2 induces breast cancer progression via activation of PI3K/AKT signaling cascade. MicroRNAs are endogenous, small non-coding RNAs that regulate gene expression at the transcriptional and posttranscriptional level. MicroRNAs pair with partially complementary sites in the 3′untranslated regions (UTRs) of target mRNAs, leading to translational repression and/or mRNA degradation. In present study we applied bioinformatics data to predict miR-1226-3p as the regulator of PI3K/AKT pathway. Then significant down regulation of three target genes EGFR, PIK3R5 and AKT2 was observed post transfection of miR-1226-3p. To validate the effect of this down regulation on cells, expression of downstream genes PCNA, C-MYC and CCND1 was evaluated. Down regulation of these genes demonstrated that cell proliferation in this breast cancer cell line was inhibited and this miRNA could be considered as a tumor suppressor.

The SPTBN4 gene, a part of the spectrin protein family, plays important roles in various cellular processes, including cell cycle, nerve cell development, and so on. Recently, a new miRNA has been found in this SPTBN4 gene, which was registered at the NCBI database. The aim of the present study was to investigate the expression of this miRNA, called SPTBN4-miR1, in the process of differentiation of human embryonal carcinoma cell line NT2 and also the overexpression effect of this miRNA on the differentiation of these cells. RT-qPCR results indicate that SPTBN4-miR1-5p and SPTBN4-miR1-3p show a significant increase in expression in the process of neural differentiation from day three until the 8th and 14th day of differentiation. Then, after overexpressing the SPTBN4-miR1 precursor in NT2 cells and retinoic acid treatment, the expression of pluripotent and differentiation revealed the role of SPTBN4-miR1-5p and SPTBN4-miR1-3p in promoting differentiation and exclusion from the pluripotent state. It seems that by making further studies and finding out the possible targets of these miRNAs, a distinctive marker can be achieved and used to improve the differentiation process.

Although more than 98% of the human genome is transcribed, most of these transcripts are not translated into proteins. Rather, they are considered as non-coding RNAs. MicroRNAs (miRNAs) are very short non-coding RNAs approximately 22 nucleotides in length which regulate many key processes of cells such as growth, proliferation, differentiation, cell cycle, apoptosis (programmed cell death) and metabolism. On the other hand, it is known that these small regulatory molecules are involved in many human diseases such as different cancers and cardiovascular disorders. Therefore, discovery and functional characterization of novel miRNAs is a primary achievement. Low abundance and spatiotemporal expression of these mediator molecules make their discovery difficult by conventional methods. Therefore, bioinformatics software has been designed for the prediction of stem-loop structures capable of producing miRNA precursors in the human genome. On the other hand, there are several bioinformatics tools for prediction of miRNA target genes. Prediction of miRNA target genes helps to characterize the function of the miRNA. In this paper, we have reviewed some of the common efficient bioinformatics tools and experimental approaches used for prediction and identification of the miRNA genes and their target genes.

MicroRNAs play pivotal role in tumorigenesis, including lung tumors. Mutations of TrkC gene are also related to lung cancers. Recently, we have discovered a novel miRNA named TrKC-miR1 (has-miR11181), located in the human TrKC gene (EBI acc # HG969187). Here, we intended to investigate TrKC-miR1 expression status in pairs of lung tumors and their marginal tissues.Total RNAs from 11 lung tumors and their marginal tissue samples were extracted. Then, real-time PCR was performed to analyze TrkC-miR1 expression, following cDNA synthesis.Data analysis revealed that TrkC-miR1 expression was elevated in squamous cell carcinoma related to marginal tumor tissues. However, TrkC-miR1 expression was decreased in large cell carcinoma and adenocarcinoma, compared to the marginal tumor tissues.Results of current study shows that TrkC-miR1 has a distinct expression pattern in different histopathological types of lung tumor. It remains to be tested in more tumor samples, if TrkC-miR1could be used as a tumor marker for distinction of lung tumor subtypes.

Plant pathogens secret their effector proteins into host cell in order to suppress plant defense system. Knowing precise molecular aspect of this invasion helps for the development of novel desease control strategies. Using yeast secretion system, a wheat leaf rust cDNA library was cloned upstream of invertase coding ORF in an expression vector and sent to the mutant yeast which is deficient for invertase production. CDNA cloneds containg signal peptid were able to secret recombinant invertase outside of the host cell and provided glucose for their growth. Using this sytem, a novel gene here we named ptGSP1, was isolated, and its expression was confirmed in the germinated and haustorial stages of the rust life sycle. Also, fast evolution of PtGSP1 coding region was deduced from comparing sequences of this gene in the geographical starins. Its secertion nature, size of the deduced protein, fast evolution of the ORF and its expression at huastorial intimate stage, all emphesis on its possible role during the pathogenesis.

Sheath blight، caused by Rhizoctonia solani AG1-IA، is one of the most destructive disease. Conventional methods of disease control using fungicides may develop new problems. Therefore، understanding molecular mechanisms of plant–pathogen interaction is necessary to adopt effective approaches for managing the disease. Here for the first time، by using bioinformatics tools and RT-PCR analysis and sequencing confirmed the presence of a Magnaporthe oryzae Avr-pita gene orthologous sequence designated as Rhiz-pita1 gene in three different geographic isolates of R. solani AG1- IA (A2،R1 and T2) genome. SignalP program predicted a secretion signal upstream of Rhiz-pita1 gene. Nucleotide sequences of 5'' region of Rhiz-pita1 gene from geographical isolates showed 99% identity in exons and 100% in introns which are characteristics of fast evolving effector proteins. Also، 98% homology between Rhiz-pita and M. oryza-pita1gene suggests that Rhiz-pita encodes an effector protein. Howevere، more researchs are necessary to confirm of this suggestion.

Cardiac cell differentiation with the help of miRNAs has recently opened a promising window for the restoration of myocardial infarction. Independent miR-1-2/133a-1 and miR-206/133b clusters are known to be expressed in cardiac and skeletal muscles، respectively. miR-133b differs from miR-133a by only one nucleotide. The sequence similarity of these two miRNAs suggests that they target the same pathways and similar mRNA targets. The present study seeks to determine if miR-133b is expressed during the cardiac cell differentiation and if its expression is in reverse correlation with the SRF and CCND2 (as potential target genes) expression patterns. Human cardiac progenitor cells were prepared from Royan Stem Cell Bank (RSCB) and differentiated into cardiomyocytes. To initiate differentiation، cells were treated with 5-azacytidine as a demethylation factor. Then، ascorbic acid and TGFB1 were added every other day and twice per week، respectively. Differentiation into cardiomyocytes was confirmed by immunocytochemistry (ICC)، flow cytometry and real-time PCR for some of the cardiac marker genes. The expression profiles of hsa-miR-133b and two of its potential target genes were also analyzed during the cardiac differentiation. Three weeks after the first differentiation induction، expression level of hsa-miR-133b was approximately five times higher than early stage expression (p<0. 05). During this process، the expression profile of SRF target gene was inversely correlated with hsa-miR-133b expression. It is known that SRF is critically involved in the cell cycle. Considering increased miR-133b and decreased SRF expression levels during the late stages of heart cell differentiation، here we speculate that elevated expression of miR-133b blocks SRF expression and decreases cardiomyocytes proliferation in order to induce differentiation with direct targeting of SRF. Taken together، our data suggest that miR-133b along with miR-133a may be involved in cardiomyocytes differentiation.