microRNA modified tumor-derived exosomes as novel tools for maturation of dendritic cells

Tumor-derived exosomes (TEX) are known by their immune suppression effects as well as initiation mediators in cancer progression and metastasis. Meanwhile, they are appropriate sources to induce immunity against tumor cells, as consist of tumor specific and associated antigens. The aim of the current study is modifying TEX with microRNA miR-155, miR-142, and let-7i, to enhance their immune stimulation ability and induce potent dendritic cells (DC). For this, exosomes were isolated from mouse mammalian breast cancer cell line; 4T1, and subjected to miR-155, miR-142, and let-7i by electroporation. Immature DCs were generated from mouse bone marrow in the presence of interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF). To mature DCs, lipopolysaccharide (LPS), TEX, and modified TEX were used. The expression level of miRNAs and their target genes (IL-6, IL-17, IL-1b, TGFβ, SOCS1, KLRK1, IFNγ, and TLR4) was determined. TEX were nanovesicles with spheroid morphology which expressed CD81, CD63, and TSG101, as exosome markers, at protein level. MHCII, CD80, and CD40 as maturation markers were assessed by flow cytometry. Overexpression of miRNAs were confirmed in exosomes and mDCs. Up and downregulation of target genes confirmed the gene network in DC maturation. We found that Let-7i could efficiently induce the DC maturation, as well as miR-142 and miR-155 have enhancing effects. These findings reveal that the modified TEX would be a hopeful cell-free vaccine for the cancer treatment.     

MicroRNA-203 reinforces stemness properties in melanoma and augments tumorigenesis in vivo

One of the challenges encountered in microRNA (miRNA) studies is to observe their dual role in different conditions and cells. This leads to a tougher prediction of their behavior as gene expression regulators. miR-203 has been identified to play a negative role in the progression of malignant melanoma; however, it has been reported, with dual effect, as both an oncomiR and tumor suppressor miRNA in some malignancies, such as breast cancer, meanwhile, the role of miR-203 in melanoma stem cells or even metastatic cells is unclear. In the present study, after observation of upregulation of miR-203 in melanoma patient's serum and also melanospheres as cancer stem cells model, we examined its overexpression on the stemness potential and migration ability of melanoma cells. Our data demonstrated that the increased miR-203 level was significantly associated with significant increase in the ability of proliferation, colony and spheres formation, migration, and tumorigenesis in A375 and NA8 cells. All of these changes were associated with enhancement of BRAF, several epithelial to mesenchymal transition factors, and stemness genes. In conclusion, our results clearly determined that miR-203 could be down-regulateddownregulated in melanoma tissues but be overexpressed in melanoma stem cells. It has an important role as oncomiR and promote repopulation, tumorigenicity, self-renewal, and migration. Therefore, we suggested overexpression of miR-203 as biomarker for early detection of metastasis. However, more studies are needed to validate our data.     

Unexpected heterogeneity due to recessive and de novo dominant mutations of GJB2 in an Iranian family with nonsyndromic hearing loss: implication for genetic counseling

Mutations in the GJB2 gene are the most common cause of nonsyndromic autosomal recessive sensorineural hearing loss (HL). A few mutations in GJB2 have also been reported to cause dominant nonsyndromic HL. Here we report a large inbred family including two individuals with nonsyndromic sensorineural hearing loss. A dominant GJB2 mutation, c.551G>A (p.R184Q), was detected in the proband, yet his parents were negative for the mutation. The second affected person had heterozygous c.35delG mutation, which was inherited from his father. Large deletions of the GJB6 gene were not detected in this family. This study highlights the importance of mutation analysis in all affected cases within a pedigree.     

Ventilatory acclimatization in response to very small changes in PO2 in humans.

Ventilatory acclimatization to hypoxia (VAH) consists of a progressive increase in ventilation and decrease in end-tidal Pco(2) (Pet(CO(2))). Underlying VAH, there are also increases in the acute ventilatory sensitivities to hypoxia and hypercapnia. To investigate whether these changes could be induced with very mild alterations in end-tidal Po(2) (Pet(O(2))), two 5-day exposures were compared: 1) mild hypoxia, with Pet(O(2)) held at 10 Torr below the subject's normal value; and 2) mild hyperoxia, with Pet(O(2)) held at 10 Torr above the subject's normal value. During both exposures, Pet(CO(2)) was uncontrolled. For each exposure, the entire protocol required measurements on 13 consecutive mornings: 3 mornings before the hypoxic or hyperoxic exposure, 5 mornings during the exposure, and 5 mornings postexposure. After the subjects breathed room air for at least 30 min, measurements were made of Pet(CO(2)), Pet(O(2)), and the acute ventilatory sensitivities to hypoxia and hypercapnia. Ten subjects completed both protocols. There was a significant increase in the acute ventilatory sensitivity to hypoxia (Gp) after exposure to mild hypoxia, and a significant decrease in Gp after exposure to mild hyperoxia (P < 0.05, repeated-measures ANOVA). No other variables were affected by mild hypoxia or hyperoxia. The results, when combined with those from other studies, suggest that Gp varies linearly with Pet(O(2)), with a sensitivity of 3.5%/Torr (SE 1.0). This sensitivity is sufficient to suggest that Gp is continuously varying in response to normal physiological fluctuations in Pet(O(2)). We conclude that at least some of the mechanisms underlying VAH may have a physiological role at sea level.     

Molecular analysis and antimicrobial susceptibility of methicillin resistant Staphylococcus aureus in one of the hospitals of Tehran University of Medical Sciences: high prevalence of sequence type 239 (ST239) clone

Methicillin-resistant Staphylococcus aureus (MRSA), particularly the multidrug-resistant clones, is an increasing worldwide problem. The average incidence rate of MRSA in Tehran was found to be over 40%. A total of 140 MRSA isolates obtained from patients attending a teaching hospital in Tehran, from May 2009 to December 2009, were included in this study. The antimicrobial susceptibility profile of MRSA isolates was determined by the agar disk diffusion method. Molecular analysis of MRSA strains was accomplished by Pulsed-Field Gel Electrophoresis (PFGE) and Multi-locus sequence typing (MLST). Detection of mecA gene was used to confirm resistance to methicillin among the MRSA isolates. All the MRSA isolates were susceptible to chloramphenicol, teicoplanin, tigecycline and vancomycin. All MRSAisolates were resistant to oxacillin, whilst 139 strains showed resistance against ciprofloxacin, erythromycin, gentamicin, tetracycline and trimethoprim-sulfamethoxazole. PFGE analysis of all the 140 MRSA isolates produced five distinct pulsotypes designated as pulsotypes A-E. Most of the isolates (n=132) were clustered into pulsotype A. The most prevalent sequence type (ST) was ST 239 (pulsotype A) found in 82% (37/45) of the tested isolates. The second most prevalent type was ST 1238 (pulsotypes B, C and D) found in 15% (7/45) of the isolates. The remaining type, ST 8 (pulsotype E) was found in a single isolate. The results of this study indicated that the MRSA clone ST 239 was a major clone in the selected university hospital of Tehran and that it was widely spread among the different wards as well as all the age groups of patients.     

Multiple-locus variable number of tandem repeats fingerprinting (MLVF) and virulence factor analysis of methicillin resistant Staphylococcus aureus SCCmec type III

Methicillin resistant Staphylococcus aureus (MRSA), particularly strains with type III staphylococcal cassette chromosome mec (SCCmec), represent a serious human pathogen in Tehran, Iran. The disease-causing capability depends on their ability to produce a wide variety of virulent factors. The prevalence of exotoxin genes and multiple-locus variable number of tandem repeats fingerprinting (MLVF) profile among MRSA isolates, from patients in Tehran, was evaluated by PCR and Multiplex-PCR. The MLVF typing of 144 MRSA isolates with type III SCCmec produced 5 different MLVF types. Generally, 97.2% (140/144) of all the isolates were positive for at least one of the tested exotoxin genes. The most prevalent genes were hld, found in 87.5% (126/144) of the isolates followed by lukE-lukD and hla found in 72.9% (105/144) and 70.1% (101/144) of the isolates, respectively. The tst gene, belonging to MLVF types I, IV and V, was found among three of the isolates from blood and wound samples. The sea gene was detected in 58.3% (84/144) of the isolates and the sed and see genes were found in one isolate with MLVF type V. The coexistence of genes was observed in the 87.5% (126/144) of the isolates. The rate of coexistence of hld with lukE-lukD, hla with lukE-lukD and sea with lukE-lukD were 66.7% (96/144), 44.4% (64/144) and 44.4% (64/144), respectively. The present study demonstrated that MRSA strains with type III SCCmec show different MLVF patterns and exotoxin profiles.     

Treatment of mercury vapor toxicity by combining deferasirox and deferiprone in rats

The hypothesis that combination of deferasirox and deferiprone chelators might be more efficient as combined therapy than single therapy in removing mercury from the body was considered. Male Wistar rats were exposed to mercury vapor for 2 weeks. After mercury administration some abnormal clinical signs such as red staining around the eyes, greenish mottling on the liver, weakness, loss of hair and weight, were observed in animals. Chelators were given orally after mercury vapor application for 2 weeks. Mercury toxicity symptoms in rats decreased after drug administration. After chelation therapy, these rats were anesthetized with ether vapor and immobilized by cervical dislocation and then their heart, liver, kidneys, intestine, spleen and testicles were sampled for determination of mercury and iron concentration. The combined chelation therapy results showed that these chelators are able to remove mercury from the body and toxicity symptoms decreased.     

Pitfalls in the use of arachidonic acid oxidation products to assign lipoxygenase activity in cancer cells

Arachidonic acid (AA) reaction with cyclooxygenase (COX) and lipoxygenases (LOX) yield eicosanoids that can mediate prostate cancer proliferation and enhance both tumour vascularization and metastasis. Increasingly measurement of eicosanoids with liquid chromatography is employed to implicate LOX activity in different biological systems and in particular link LOX activity to the progression of cancer in experimental models. This study demonstrates that simply identifying patterns of eicosanoid regio-isomerism is insufficient to designate LOX activity in prostate cancer cells and the analysis must include complete stereochemical assignment of the various isomers in order to validate the assignment of LOX activity.     

Tris-chelated complexes of nickel(II) with bipyridine derivatives: DNA binding and cleavage,BSA binding,molecular docking,and cytotoxicity

Abstract

Two nickel(II) complexes with substituted bipyridine ligand of the type [Ni(NN)₃](ClO₄)₂, where NN is 4,4′-dimethyl-2,2′-bipyridine (dimethylbpy) (1) and 4,4′-dimethoxy-2,2′-bipyridine (dimethoxybpy) (2), have been synthesized, characterized, and their interaction with DNA and bovine serum albumin (BSA) studied by different physical methods. X-ray crystal structure of 1 shows a six-coordinate complex in a distorted octahedral geometry. DNA-binding studies of 1 and 2 reveal that both complexes sit in DNA groove and then interact with neighboring nucleotides differently; 2 undergoes a partial intercalation. This is supported by molecular-docking studies, where hydrophobic interactions are apparent between 1 and DNA as compared to hydrogen bonding, hydrophobic, and π–π interactions between 2 and DNA minor groove. Moreover, the two complexes exhibit oxidative cleavage of supercoiled plasmid DNA in the presence of hydrogen peroxide as an activator in the order of 1?>?2. In terms of interaction with BSA, the results of spectroscopic methods and molecular docking show that 1 binds with BSA only via hydrophobic contacts while 2 interacts through hydrophobic and hydrogen bonding. It has been extensively demonstrated that the nature of the methyl- and methoxy-groups in ligands is a strong determinant of the bioactivity of nickel(II) complexes. This may justify the above differences in biomolecular interactions. In addition, the in vitro cytotoxicity of the complexes on human carcinoma cells lines (MCF-7, HT-29, and U-87) has been examined by MTT assay. According to our observations, 1 and 2 display cytotoxicity activity against selected cell lines.

Communicated by Ramaswamy H. Sarma