Impact of miRNAs expression modulation on the methylation status of breast cancer stem cell-related genes

Purpose Altered miRNAs play a crucial role in the emergence of the breast cancer stem cell (BCSC) phenotype. The interplay between miRNAs and methylation enzymes has been documented. One of the most aggressive breast cancer cell lines, MDA-MB-231, has expressed much more DNMT3B than DNMT3A. This study aims to evaluate the ability of miR-203 restoration and miR-150 inhibition to regulate DNMT3B and DNMT3A to modify the methylation level of BCSC-associated genes. Methods MDA-MB-231 cells were transfected with miR-203 mimic or miR-150 inhibitor or DNMT3B siRNA, and downstream analysis was performed by flow cytometry, real-time PCR and Western blotting. Results DNMT3A and DNMT3B are regulated both by miR-203a-3p and miR-150-5p. Transfection with miR-203 mimic and miR-150 inhibitor significantly reduced the CD44+CD24− subpopulation and down-regulated the expression of CD44 mRNA by increasing promoter methylation levels. SiRNA knockdown of DNMT3B increased the CD44+CD24− subpopulation and the expression of CD44 and ALDH1A3 by decreasing methylation density. The inhibition of miR-150 down-regulated OCT3/4 and SOX2 expression without affecting methylation levels, while miR-203 restoration and miR-150 inhibition down-regulated NANOG expression by elevating the methylation level. A positive-feedback loop was found between miR-203 and its target DNMT3B, as restoring miR-203 suppressed DNMT3B, while knocking down DNMT3B up-regulated miR-203. The restoration of miR-203 and knockdown of DNMT3B decreased methylation levels and increased the expression of miR-141 and miR-200c. Conclusions The study concluded that miR-203 and miR-150 play a role in the regulation of genes involved in BCSC methylation, including other miRNAs, by targeting DNMT3B and DNMT3A (AU)

Impact of miRNAs expression modulation on the methylation status of breast cancer stem cell-related genes.

PURPOSE: Altered miRNAs play a crucial role in the emergence of the breast cancer stem cell (BCSC) phenotype. The interplay between miRNAs and methylation enzymes has been documented. One of the most aggressive breast cancer cell lines, MDA-MB-231, has expressed much more DNMT3B than DNMT3A. This study aims to evaluate the ability of miR-203 restoration and miR-150 inhibition to regulate DNMT3B and DNMT3A to modify the methylation level of BCSC-associated genes. METHODS: MDA-MB-231 cells were transfected with miR-203 mimic or miR-150 inhibitor or DNMT3B siRNA, and downstream analysis was performed by flow cytometry, real-time PCR and Western blotting. RESULTS: DNMT3A and DNMT3B are regulated both by miR-203a-3p and miR-150-5p. Transfection with miR-203 mimic and miR-150 inhibitor significantly reduced the CD44+CD24- subpopulation and down-regulated the expression of CD44 mRNA by increasing promoter methylation levels. SiRNA knockdown of DNMT3B increased the CD44+CD24- subpopulation and the expression of CD44 and ALDH1A3 by decreasing methylation density. The inhibition of miR-150 down-regulated OCT3/4 and SOX2 expression without affecting methylation levels, while miR-203 restoration and miR-150 inhibition down-regulated NANOG expression by elevating the methylation level. A positive-feedback loop was found between miR-203 and its target DNMT3B, as restoring miR-203 suppressed DNMT3B, while knocking down DNMT3B up-regulated miR-203. The restoration of miR-203 and knockdown of DNMT3B decreased methylation levels and increased the expression of miR-141 and miR-200c. CONCLUSIONS: The study concluded that miR-203 and miR-150 play a role in the regulation of genes involved in BCSC methylation, including other miRNAs, by targeting DNMT3B and DNMT3A.

Novel mutations of the LHCGR gene in two families with 46,XY DSD causing Leydig cell hypoplasia I.

PURPOSE: Leydig cell hypoplasia is a rare autosomal recessive 46,XY disorder of sexual development (DSD). It is caused by homozygous or compound heterozygous inactivating mutations in the human luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) gene. In Leydig cell hypoplasia type I, patients are characterized by predominantly female external genitalia, which usually go unrecognized until the age of puberty. METHODS: This study reports three patients descending from two unrelated families. We performed clinical, hormonal, histopathological, molecular, and bioinformatics studies for the studied cases. RESULTS: All investigations suggested 46,XY DSD and Leydig cell hypoplasia. Molecular analysis showed two novel homozygous inactivating mutations (p.Glu148Ter and p.Leu104Pro) within the extracellular domain of the LHCGR gene. CONCLUSION: Although the mutations of the LHCGR gene are distributed heterogeneously, without hotspot or recurrent mutations, about one fifth of the reported mutations worldwide have been detected in Arab patients. This is probably due to the high consanguinity rate in these populations, which increases the percentage of autosomal recessive disorders and the homozygous LHCGR gene mutations.

A novel nonsense mutation in exon 1 of HSD17B3 gene in an Egyptian 46,XY adult female presenting with primary amenorrhea.

17-ß-Hydroxysteroid dehydrogenase type 3 deficiency is a rare autosomal recessive cause of 46,XY disorder of sex development. Worldwide, about 30 mutations in the hydroxysteroid (17-beta) dehydrogenase 3 (HSD17B3) gene have been reported, involving all exons except exon 1. Herein, we investigated an Egyptian female with 46,XY karyotype and low testosterone/Δ4-androstenedione ratio. Genomic DNA was extracted from blood samples, and then, direct DNA sequencing of HSD17B3 gene was performed. The patient had a homozygous mutation c.198G>A in exon 1 resulting in a stop codon (p.W50X). The study presents the first mutation to be reported in exon 1 of the HSD17B3 gene.

Unique karyotype: mos 46,X,dic(X;Y)(p22.33;p11.32)/ 45,X/45,dic(X;Y)(p22.33;p11.32) in an Egyptian patient with Ovotesticular disorder of sexual development.

Ovotesticular disorder of sexual development (OT-DSD) is an unusual form of DSD, characterized by the coexistence of testicular and ovarian tissue in the same individual. In this report, we present clinical, cytogenetic and molecular data of an Egyptian patient with ambiguous genitalia and OT-DSD, who had a unique karyotype comprising 3 different cell lines: mos 46,X,dic(X;Y)(p22.33;p11.32)/45,X/ 45,dic(X;Y)(p22.33;p11.32). This mosaic karyotype probably represents 2 different events: abnormal recombination between the X and Y chromosomes during paternal meiosis and postzygotic abnormality in mitotic segregation of the dic(X;Y) chromosome, resulting in a mosaic karyotype. The presence of the sex-determining region Y (SRY) gene explains the development of testicular tissue. On the other hand, other factors, including the presence of a 45,X cell line, partial SRY deletion, X inactivation pattern, and position effect, could be contributed to genital ambiguity. Explanation of the patient's phenotype in relation to the genotype is discussed with a literature review. We conclude that FISH analysis with X- and Y-specific probes and molecular analysis of the SRY gene are highly recommended and allow accurate diagnosis for optimal management of cases with ambiguous genitalia.

ACE gene polymorphism in Egyptian children with idiopathic nephrotic syndrome.

BACKGROUND: Idiopathic nephrotic syndrome is a common renal disease in children. ACE gene insertion/deletion (I/D) polymorphism has been studied as a predictor of clinical response to steroid therapy. OBJECTIVE: To investigate the distribution of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in children with idiopathic nephrotic syndrome (INS), as well as its relation with patient's clinical response to steroid therapy. METHODS: The studied subjects included 50 children with INS compared to 20 unrelated healthy children. Each individual genotype was determined using PCR amplification of extract genomic DNA and allele distribution based on size of the PCR fragments. RESULTS: Patients with INS had a significantly higher percentage of DD genotype (p < 0.05) than the control group. D allele frequency was significantly higher in INS patients than healthy controls. CONCLUSION: Our results showed that INS is associated with a higher incidence of DD genotype, especially in non-SS patients. This data suggested that DD genotype may play a role in the clinical response to steroid. Angiotensin II may be involved in part in the response to steroid treatment in children with INS (Tab. 4, Fig. 1, Ref. 20).

Screening for six Mediterranean mutations in 90 Egyptian patients with phenylketonuria.

OBJECTIVES: The aim of this study is to assess the prevalence of six common mutations in the Mediterranean basin and Turkey among a large group of Egyptian PKU cases BACKGROUND: Phenylketonuria (PKU) is one of the most common inborn errors of amino acid metabolism that is caused by deficiency of hepatic phenylalanine hydroxylase (PAH). This deficiency is attributed to more than 528 mutations in the PAH gene. METHODS: Ninety unrelated patients with PKU (180 alleles) were screened for six mutations (IVS10-11G>A, R261Q, R252W, Y277D, E221G and G272S) using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The IVS10-11G>A mutation was found in thirty alleles (17%), the R261Q in twelve (7%) and R252W in three (1.6%), while Y277D, E221G and G272S were not found in this patient group. CONCLUSION: Screening for six Mediterranean mutations identified a heterogeneous pattern among Egyptian PKU patients with a high frequency of IVS10-11 G>A (17%) (Tab. 2, Ref. 31). Full Text (Free, PDF) www.bmj.sk.

Molecular analysis of SMN1 and NAIP genes in Egyptian patients with spinal muscular atrophy.

OBJECTIVES: The aim of this study is to provide preliminary molecular data on spinal muscular atrophy in Egyptian patients thus facilitating a rapid and conventional molecular assay for accurate diagnosis of SMA. BACKGROUND: Childhood spinal muscular atrophy (SMA) is one of the most common autosomal recessive disorders. It is characterized by symmetrical muscle weakness and atrophy of limbs and trunk. At least four SMA related genes have been identified [survival motor neuron (SMN), neuronal apoptosis inhibitory protein (NAIP), the gene encoding the transcriptional factor p44 and H4F5 gene]. METHODS: Homozygous absence of exons 7 and 8 of the SMN1 gene was detected using PCR-SSCP analysis, while NAIP gene deletion was detected using multiplex PCR-agarose gel electrophoresis. RESULTS: Homozygous absence of SMN1 exons 7 and 8, or exon 7 only, was found in 80% of patients. Of those patients, 45% were also deleted for NAIP exon 5. CONCLUSION: The molecular basis of SMA in Egyptian patients has a similar pattern to that reported in most populations, but a larger study is recommended for more comprehensive characterization (Tab. 1, Fig. 2, Ref. 33).