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.

Effect of topical mometasone furoate on adenoidal lymphoid tissue: a light microscopic study.

BACKGROUND: Adenoid hypertrophy is a common cause of upper airway obstruction, and adenoidectomy is one of the most frequently performed operations in children. Topical nasal steroids can act directly on nasopharyngeal lymphoid tissue to decrease its reactive inflammatory changes and potentially reduce its size. OBJECTIVE: To study the light microscopic changes in adenoidal lymphoid tissue after one month of topical steroid use. METHODS: Twenty-six children with adenoid hypertrophy grade 3 scheduled for adenoidectomy were randomly divided into two equal groups: one group received mometasone furoate aqueous nasal spray (Nasonex) 100 mcg/day for four weeks, and a control group received nasal normal saline 0.9 per cent for four weeks. The removed adenoids were examined histopathologically. RESULTS: Adenoidal tissue from the mometasone group had less reactive germinal centres and less spongiosis compared to the control group. The latter showed proliferating, reactive, variable sized and shaped lymphoid follicles, with congested blood vessels in the interfollicular areas. CONCLUSION: The use of intranasal mometasone furoate aqueous nasal spray (Nasonex) for one month reduced adenoidal tissue reactive cellular changes and its vascularity. This is, however, a pilot study; a longer treatment period is needed to assess the effect of treatment on adenoidal size.

Design of potent and selective dynorphin A related peptides devoid of supraspinal motor effects in mice.

Dynorphin A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro (Dyn Ia) was previously shown to be a highly potent and selective kappa opioid peptide. Four analogs of Dyn Ia are synthesized by the solid-phase procedure, introducing pseudo CH2NH linkage between positions 6 and 7 as follows: analog 1, [6 psi 7 (CH2NH)]Dyn Ia; analog 2, [6 psi 7 (CH2NH), D-Leu8]Dyn Ia; analog 3, [N(Me)-Tyr1, 6 psi 7 (CH2NH)]Dyn Ia; and analog 4, [N(Me)-Tyr1, 6 psi 7 (CH2NH), D-Leu8]Dyn Ia. The purified peptides are compared in vitro with Dyn Ia for their ability to compete with the binding of selective kappa, mu, and delta opioid ligands using membrane preparations of guinea pig cerebellum (kappa) and rat brain (mu and delta). The synthetic compounds are also compared in vivo in mice (intracerebroventricularly administered) for their analgesic activity against acetic acid induced writhing and their ability to produce motor dysfunction. All compounds display a high affinity (Ki = 0.5-1.8 nM) and a good selectivity for the kappa opioid receptor, and their rank order of potency on the kappa site (analog 2 > analog 1 > analog 3 > analog 4) closely parallels their potency (AD50 = 1.57-5 nmol/mouse) in inhibiting acetic acid induced writhing in mice (analog 2 > analog 1 > analog 4 > analog 3). On the other hand, all the synthetic analogs are less potent than Dyn Ia in producing motor effects, analog 2 being the least potent (CD50 = 15.4 nM as compared with 2.9 nM for Dyn Ia).(ABSTRACT TRUNCATED AT 250 WORDS)