mRNA Expression Levels Of DNMT3a Research Articles

Increased Expression of DNA Methyltransferase 1 and 3B Correlates with Tumor Grade in Laryngeal Squamous Cell Carcinoma

Background: DNA methyltransferase (DNMT) enzymes, encoded by DNMT1, DNMT3A andDNMT3B genes, play a major role in the development of cancers through aberrant promotermethylation. Due to little information about the biological and clinical significance of expressionchanges of these genes in Laryngeal Squamous Cell carcinoma (LSCC), the current study wasdesigned to evaluate the contribution of DNMTs expression as potential diagnostic biomarkersin progression of LSCC. Methods: DNMT1, DNMT3A and DNMT3B expressions in tumoral and normal tissues fromthirty-three LSCC patients were evaluated by relative comparative real-time PCR, prior toany therapeutic intervention. Relationship between genes expression and clinicopathologicalfeatures were also analyzed. Results: The mRNA expression levels of all three DNMTs (DNMT1, DNMT3A and DNMT3B)were significantly elevated in LSCC tumor specimens compared to that of non-tumor tissues(P<0.0001, P=0.011 and P<0.0001, respectively). The expression of DNMT1 and DNMT3Bwas strongly associated with histopathological tumor grade. Moreover, the mRNA expressionlevels of DNMT3A were significantly correlated with laryngopharyngeal reflux. No significantrelationships existed with other clinicopathological parameters. Conclusion: Data showed that the expression levels of DNMT1, DNMT3A and DNMT3Bmarkedly increased in LSCC tissues. DNMT1 and DNMT3B were mainly overexpressed in highgrade LSCC tumors, therefore, they may have a role in LSCC progression. It seems that thesegenes may serve as diagnostic biomarkers in development of LSCC.

MicroRNA-30a-3p inhibits the progression of lung cancer via the PI3K/AKT by targeting DNA methyltransferase 3a.

BackgroundMicroRNAs (miRNAs) are small non-coding RNAs, involved in pathological and physiological processes via regulating target genes expression. Abnormally expressed miR-30a-3p has been verified in several tumors, such as liver cancer, esophageal cancer and lung cancer. It was reported that DNA methylation plays a critical role in the tumorigenesis of lung cancer through regulated tumor suppressor genes silencing. Nevertheless, the potential mechanism of miR-30a-3p in restoring abnormal DNA methylation patterns is still unclear in lung cancer. Therefore, because the miR-30a-3p is complementary to the 3ʹ-untranslated regions (3ʹ-UTR) of DNA methyltransferase 3A (DNMT3A), we investigated whether miRNA-30a-3p could target DNMT3a to regulate the progression of lung cancer cell.MethodsqRT-PCR was used to evaluate miR-30a-3p and DNMT3a mRNA expression levels in A549 lung cancer cells and normal cell line BEAS-2B. MiR-30a-3p expression plasmid was transferred into A549 cells. The target of miR-30a-3p was detected by luciferase reporter assay. Western blot was used to measure related protein expression levels. MTT assay was used to measure the proliferation of cells in each group. The cycle and apoptosis of cells were detected by flow cytometry.ResultsWe found down-regulation of miR-30a-3p mRNA expression and up-regulation of DNMT3a mRNA expression in A549 cells. Overexpression of miR-30a-3p downregulates DNMT3a or blocked DNMT3a by interference vector, significantly inhibited the proliferation and G1/S transition in A549 cells via regulating p38 MAPK pathway, and induced the apoptosis in A549 cells via regulating Bcl-2/Bax protein levels. Furthermore, we observed the opposite phenomenon in A549 cells transfected with both miR-30a-3p and DNMT3a vector.ConclusionOur data show that miR-30a-3p suppressed the progression of lung cancer via regulating p38 MAPK pathway by targeting DNMT3A in A549 cells, indicating that miR-30a-3p might be a novel potential therapeutic strategy in the treatment of lung cancer.

Differences in Expression Patterns of DNMTs and TSG Proteins in Lymphoid Tissue Section Play an Important Role in Their Association

In situ, patterns of expression of DNMTs (DNA methytransferases) in normal reactive tonsillar tissue have been examined. Difference in pattering of expression of DNMTs and TSG (Tumor suppressor genes) proteins in lymphoid tissue section is an important question in relation to their association with each other as well as relationship to mRNA gene expression level. In order to examine this issue, we examined DNMTs and TSG proteins expression by immunohistochemistry in sections of paraffin-embedded specimens obtained from 33 subjects of lymphoma and 16 subjects of Non-malignant tissues after receiving written informed consent. The specimens were stained with anti-DNMTs (DNMT1, DNMT3A and DNMT3B) and anti-TSG (E-cadherin, H-cadherin and ADAMTS18) antibodies. In addition, using fresh-frozen optimal cutting temperature (OCT) compound-embedded tissue specimens before any treatment, we examined mRNA expression levels and promoter methylation status of E-cadherin (CDH1), H-cadherin (CDH13) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS18) using quantitative real-time PCR (qRT-PCR) and methylation-specific PCR (MSP), respectively. The expression of nuclear DNMTs proteins (DNMT1 and 3A) in lymphoma section was observed in [17/33 (51%); 27/33 (81%)], whereas in non-malignant tissues was [14/16 (87.5%); 13/16 (81%)], respectively. The DNMT3B protein expression was not detected in our tissue samples, which might be explained by the fact that DNMT3B characterized by alternative splicing as shown previously. Membrane proteins (E-cadherin, H-cadherin and ADAMTS18) showed low expression [12/33 (36%); 10/33 (30%); 6/33 (18%), respectively], when compared to non-malignant tissue sections [12/16 (75%); 7/16 (43%); 8/16 (50%), respectively]. The expression levels of CDH1, CDH13 and ADAMTS18 mRNAs were non-significantly reduced in their corresponding protein negative expression compared to the levels in cases with positive protein expression (p =0.112, p =0.378, p =0.077, respectively). We could not find any correlation between mRNA/protein expression levels of DNMTs and the methylation status of CDH1, CDH13 and ADAMTS18. Importantly, by immunostaining especially in non-malignant lymphoid tissues, we found that DNMT1 was highly detected in germinal center B cells (GC B cells) with gradual decrease or no expression in the mantle, marginal, interfollicular and T cells zones. Whereas DNMT3A was preferentially and scattered like expressed in the cells of the surrounding zones out of the germinal centers. Furthermore, E-cadherin, H-cadherin and ADAMTS18 proteins expression were detected on the cell surface membrane of the cells outside the GC but at rates somehow more than those cells inside the GC (Fig. 1). This is supported by the significant association observed between the frequency of DNMT3A with both E-cadherin and ADAMTS18, protein expressions (Chi square: p <0.05), while no association with H-cadherin protein expression. In addition, DNMT1 protein expression did not show significant association with the protein expressions of E-cadherin, H-cadherin and ADAMTS18. Moreover, the mRNA expression levels of DNMT3A and 3B showed high significant levels (p <0.05) in cases with negative protein expressions of both E-cadherin and ADAMTS18 when compared to cases with positive protein expressions (Fig. 2A and C). The DNMT1 mRNA expression level did not show any significant difference between the negative and positive protein expressions of E-cadherin, H-cadherin and ADAMTS18 (Fig. 2B). Furthermore, there was no significant association between the mRNA levels of DNMTs and H-cadherin protein expression. Expression of H-cadherin protein was frequently observed in the endothelial venules and trabeculae of the lymphoid tissues (Fig. 1) which might cause of its lack of association with both DNMT1 and DNMT3A. In conclusion, these results indicate that as a result of differences in pattering of DNMTs and TSG protein expressions detected in lymphoid tissues by immunohistochemistry staining, it might be one of the reasons of the association with each other and their mRNA expression levels across the spectrum of lymphomas and non-malignant lymphoid tissues. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Aberrant DNA methylation status in human uterine leiomyoma

Aberrant DNA methylation has been implicated in tumorigenesis. This study was undertaken to establish the genome-wide DNA methylation profile in uterine leiomyomas and to investigate whether DNA methylation status is altered in uterine leiomyomas. For this purpose, restriction landmark genomic scanning (RLGS) was performed on a paired sample of leiomyoma and adjacent normal myometrium. The RLGS profile revealed 29 aberrant methylation spots (10 methylated and 19 demethylated) in leiomyoma in comparison with myometrium. One of the differently methylated genomic loci was newly identified as GS20656 from the human genome sequence database. In 9 of the 10 paired samples, the DNA methylation levels of the first exon of GS20656 were significantly lower in leiomyoma than in myometrium, suggesting the existence of a genomic locus under epigenetic regulation in uterine leiomyomas. Unexpectedly, DNA methyltransferase 1 (DNMT1) and DNMT3a mRNA expression levels were higher in leiomyoma than in myometrium. These facts suggest that other epigenetic factors besides DNMT are involved in local changes of DNA methylation at genome loci. The present study indicates not only aberrant genome-wide DNA methylation status in uterine leiomyomas but also the existence of a genomic locus that is differently methylated between normal myometrium and uterine leiomyoma.

Decreased DNA Methyltransferase 3A and 3B mRNA Expression in Peripheral Blood Mononuclear Cells and Increased Plasma SAH Concentration in Adult Patients with Idiopathic Thrombocytopenic Purpura

DNA methylation is known to play an important role in gene transcription and alterations of methylation contribute to the development of certain disorders such as cancer and immunodeficiency. Recent years have found an increasing interest in the role of epigenetic modifications in the etiology of human autoimmune diseases, such as systemic lupus erythromatosus (SLE) and rheumatoid arthritis (RA). DNA methyltransferases (DNMTs) are involved in the epigenetic control of DNA methylation processes. S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), as the substrate and product of essential cellular methyltransferase reactions, have important indicator action of cellular methylation status. The aim of this study is to explore if DNA methylation plays a role in the pathogenesis of idiopathic thrombocytopenic purpura (ITP). DNMT1, DNMT3A, and DNMT3B mRNA expression in peripheral blood mononuclear cells (PBMCs) of adult ITP patients were analyzed by real-time quantitative polymerase chain reaction. Plasma SAM and SAH levels were assayed with reversed-phase high performance liquid chromatography (HPLC). DNMT3A and DNMT3B mRNA expressions were significantly lower in ITP patients than in healthy controls (p < 0.001), while DNMT1 mRNA expression was not significantly different between the two groups (p = 0.774). Plasma SAH concentration was significantly elevated in ITP patients than in healthy controls (p < 0.05), while the plasma SAM and SAM/SAH were not significantly different between the two groups (p = 0.133, p = 0.624 respectively). Our observations suggest that aberrant DNA methylation status reflected by increased plasma SAH concentration and decreased mRNA expression levels of DNMT3A and 3B are possibly involved in the pathogenesis of ITP although the precise mechanisms need further study.