Mitochondrial targeting drug lonidamine triggered apoptosis in doxorubicin-resistant HepG2 cells

Mitochondria play a crucial role in the induction and execution of apoptosis. Accordingly, recent suggestions have been made to use agents that directly act on mitochondria to trigger apoptosis so that drug-sensitive and-resistant tumour cells can be eliminated. To test this hypothesis, human hepatocarcinoma HepG2 and its derivative R-HepG2 with doxorubicin (Dox) resistance as a result of expression of P-glycoprotein were used to investigate the effect of lonidamine (LND), a new mitochondrial targeting drug, on the induction of apoptosis. Results from our study indicate that R-HepG2 cells were more sensitive to LND than parental cells in terms of cytotoxicity determined by alamar blue assay. Cell death induced by LND was associated with the hallmarks of apoptosis such as mitochondrial membrane depolarization, release of cytochrome c, phosphatidyl-serine externalization and DNA fragmentation. Moreover, combined treatment of cells with Dox and LND elicited more cell death. Taken together, our results suggest a potential use of LND as an anti-cancer drug to bypass drug resistance and to trigger tumour destruction through apoptosis in HepG2 and R-HepG2 cells.     

An ultrastructural and histochemical study of the development of secondary palate in Japanese quail, Coturnix coturnix japonica

Embryonic development of the secondary palate of the Japanese quail, Coturnix coturnix japonica, was studied. The palatal shelves appeared on day 5 of incubation in a horizontal direction over the dorsal surface of the tongue. Subsequently, unlike those in mammals, the opposing palatal shelves do not fuse, and a physiological cleft persists between them. In comparison with the chick, where the palatal shelves do not fuse and the medial edge epithelium (MEE) becomes orthokeratinized stratified squamous type, the quail MEE differentiates into a parakeratinized stratified squamous type. The basal cells of the quail MEE differentiated from cuboidal to columnar and showed reorganization of their cytoplasmic organelles. In contrast to both the chick and mammalian MEE, quail MEE showed very little ruthenium red (RR) binding at the plasma membrane of both the basal and superficial cells. Initial development in a horizontal direction, lack of fusion, and an absence of programmed cell death in MEE of developing quail palate distinguished it from the mammalian palatogenesis. Also, although the morphogenesis of palate in quail and chick was similar, the pattern of cytodifferentiation in their MEE was different, which may be attributed to their ontogenesis.     

Hierarchical Clustering of Breast Cancer Methylomes Revealed Differentially Methylated and Expressed Breast Cancer Genes

Oncogenic transformation of normal cells often involves epigenetic alterations, including histone modification and DNA methylation. We conducted whole-genome bisulfite sequencing to determine the DNA methylomes of normal breast, fibroadenoma, invasive ductal carcinomas and MCF7. The emergence, disappearance, expansion and contraction of kilobase-sized hypomethylated regions (HMRs) and the hypomethylation of the megabase-sized partially methylated domains (PMDs) are the major forms of methylation changes observed in breast tumor samples. Hierarchical clustering of HMR revealed tumor-specific hypermethylated clusters and differential methylated enhancers specific to normal or breast cancer cell lines. Joint analysis of gene expression and DNA methylation data of normal breast and breast cancer cells identified differentially methylated and expressed genes associated with breast and/or ovarian cancers in cancer-specific HMR clusters. Furthermore, aberrant patterns of X-chromosome inactivation (XCI) was found in breast cancer cell lines as well as breast tumor samples in the TCGA BRCA (breast invasive carcinoma) dataset. They were characterized with differentially hypermethylated XIST promoter, reduced expression of XIST, and over-expression of hypomethylated X-linked genes. High expressions of these genes were significantly associated with lower survival rates in breast cancer patients. Comprehensive analysis of the normal and breast tumor methylomes suggests selective targeting of DNA methylation changes during breast cancer progression. The weak causal relationship between DNA methylation and gene expression observed in this study is evident of more complex role of DNA methylation in the regulation of gene expression in human epigenetics that deserves further investigation.     

Comparative genomic analysis reveals significant enrichment of mobile genetic elements and genes encoding surface structure-proteins in hospital-associated clonal complex 2 Enterococcus faecalis

Background  

Enterococci rank among the leading causes of nosocomial infections. The failure to identify pathogen-specific genes in Enterococcus faecalis has led to a hypothesis where the virulence of different strains may be linked to strain-specific genes, and where the combined endeavor of the different gene-sets result in the ability to cause infection. Population structure studies by multilocus sequence typing have defined distinct clonal complexes (CC) of E. faecalis enriched in hospitalized patients (CC2, CC9, CC28 and CC40).     

Regenerative potential of human muscle stem cells in chronic inflammation

Introduction

Chronic inflammation is a profound systemic modification of the cellular microenvironment which could affect survival, repair and maintenance of muscle stem cells. The aim of this study was to define the role of chronic inflammation on the regenerative potential of satellite cells in human muscle.

Methods

As a model for chronic inflammation, 11 patients suffering from rheumatoid arthritis (RA) were included together with 16 patients with osteoarthritis (OA) as controls. The mean age of both groups was 64 years, with more females in the RA group compared to the OA group. During elective knee replacement surgery, a muscle biopsy was taken from the distal musculus vastus medialis. Cell populations from four RA and eight OA patients were used for extensive phenotyping because these cell populations showed no spontaneous differentiation and myogenic purity greater than 75% after explantation.

Results

After mononuclear cell explantation, myogenic purity, viability, proliferation index, number of colonies, myogenic colonies, growth speed, maximum number of population doublings and fusion index were not different between RA and OA patients. Furthermore, the expression of proteins involved in replicative and stress-induced premature senescence and apoptosis, including p16, p21, p53, hTERT and cleaved caspase-3, was not different between RA and OA patients. Mean telomere length was shorter in the RA group compared to the OA group.

Conclusions

In the present study we found evidence that chronic inflammation in RA does not affect the in vitro regenerative potential of human satellite cells. Identification of mechanisms influencing muscle regeneration by modulation of its microenvironment may, therefore, be more appropriate.     

Potential application of hydrogel-based strong anion-exchange membrane for plasmid DNA purification

The potential application of a hydrogel-based strong anion-exchange (Q) membrane to purify plasmid DNAs was evaluated. The maximum binding capacity of plasmid DNA was estimated to be 12.4 mg/ml of membrane volume with a plasmid recovery yield of ～90%. The effect of the inherent properties of plasmid DNA, membrane adsorbent, and the ionic environment on membrane performance was systematically investigated. Plasmid DNAs with smaller tertiary structure tended to have a better recovery than those with larger tertiary structure. Environmental Scanning Electron Microscopy (ESEM) revealed that the hydrogel structure is more porous on one side of membrane than the other. Membrane pre-treatment significantly improved pore distribution and increased membrane porosity resulting in a better adsorption, recovery, and higher flux. The selection of proper operating pH led to further improvement. The relative contribution of these factors to improve membrane chromatography of plasmid DNAs was analyzed using statistical modeling. It was found that the adsorption of plasmid DNA was mainly affected by the available adsorptive area associated with membrane porosity, whereas the recovery of plasmid DNAs was mainly affected by the environmental pH.     

The new locally endemic genus Yazdana (Caryophyllaceae) and patterns of endemism highlight the high conservation priority of the poorly studied Shirkuh Mountains (central Iran)

Although mountain ranges are often recognized as global biodiversity hotspots with a high level of endemism, diversity and biogeographic connections of isolated and weakly explored mountains remain poorly understood. This is also the case for Shirkuh Mts. in central Iran. Here, Yazdana shirkuhensis gen. & spec. nov. (Caryophylleae, Caryophyllaceae) is described and illustrated from the high alpine zone of this mountain. Molecular phylogenetic analyses of nuclear and plastid DNA sequence data show that Y. shirkuhensis is related to Cyathophylla and Heterochroa (tribe Caryophylleae). The newly described genus and species accentuate Shirkuh Mts. as a center of endemism, which harbors a high number of narrowly distributed species, mostly in high elevations reaching alpine habitats. As this area is currently not protected, a conservation priority is highlighted for high elevations of Shirkuh Mts.