Overexpression of PPARγ can down-regulate Skp2 expression in MDA-MB-231 breast tumor cells

Skp2 is frequent amplified and overexpressed in breast cancer, making it a potential molecular target for cancer therapy. The objective of this study was to examine the effect of PPARγ overexpression on Skp2 expression in breast cancer cell lines. First, we investigated the role of PPARγ and Skp2 in human breast cancer progression. Immunohistochemical analysis of 70 specimens on formalin-fixed paraffin sections was performed. Furthermore in vitro, Western blot analysis was used to study the relationship between PPARγ and Skp2. We found that the expression of PPARγ and Skp2 expression was inverse correlation whether in vivo or in vitro. In addition, PPARγ overexpression can down-regulate the expression of Skp2 mRNA and protein in breast cancer cells. PPARγ overexpression decreased breast cancer cell proliferation and induced spontaneous apoptosis even in the absence of exogenous ligand. These PPARγ-overexpressing cells were dramatically more sensitive to PPARγ ligand-induced apoptosis compared with parental or Myc-control transfected cells. Overexpressing of Skp2 partially reversed PPARγ’s pro-apoptotic and anti-proliferative abilities. These results suggested that PPARγ’s pro-apoptotic and anti-proliferative abilities appear to be triggered at least in part by the modulation of Skp2.     

Development and application of a loop-mediated isothermal amplification method on rapid detection <Emphasis Type="Italic">Escherichia coli</Emphasis> O157 strains from food samples

We developed and evaluated the specificity and sensitivity of a loop-mediated isothermal amplification (LAMP) method for rapid detection of the food-borne Escherichia coli O157 strains. Six primers, including outer primers, inner primers and loop primers, were specially designed for recognizing eight distinct sequences on three targets, which were rfbE, stx1 and stx2. The detection limits were found to be 100, 100 and 10 fg DNA/tube for rfbE, stx1 and stx2, respectively. Application of LAMP assays were performed on 417 food-borne E. coli strains, the sensitivity of LAMP assays for the rfbE, stx1 and stx2 was 100, 95.3 and 96.3%, and the negative predictive value was 100, 96.7 and 97.1%, respectively; with a 100% specificity and positive predictive value for all three targets.     

Detection of Sapovirus in oysters

SaV sequences which are either genetically identical or similar were detected from oysters, feces from gastroenteritis patients, and domestic wastewater samples in geographically close areas. This is the first report of the detection of SaV in oysters which meet the legal requirements for raw consumption in Japan.     

The combination of ADI-PEG20 and TRAIL effectively increases cell death in melanoma cell lines

Current treatment for advanced, metastatic melanoma is not very effective, and new modalities are needed. ADI-PEG20 is a drug that specifically targets ASS-negative malignant melanomas while sparing the ASS-expressing normal cells. Although laboratory research and clinical trials showed promising results, there are some ASS-negative cell lines and patients that can develop resistance to this drug. In this report, we combined ADI-PEG20 with another antitumor drug TRAIL to increase the killing of malignant melanoma cells. This combination can greatly inhibit cell growth (to over 80%) and also enhanced cell death (to over 60%) in four melanoma cell lines tested compared with control. We found that ADI-PEG20 could increase the cell surface receptors DR4/5 for TRAIL and that caspase activity correlated with the increased cell death. These two drugs could also increase the level of Noxa while decrease that of survivin. We propose that these two drugs can complement each other by activating the intrinsic and extrinsic apoptosis pathways, thus enhance the killing of melanoma cells.     

Effect of food deprivation on the ambulatory movement of the Colorado potato beetle,Leptinotarsa decemlineata

Modification of dispersal behaviour is a common response of insects to food and water deprivation. The literature suggests that different insects respond with different strategies: changing walking parameters, switching dispersal mode (walking to flight or vice versa), or changing the host searching path. The goal of this study was to add to the limited literature on the subject by investigating, whether the walking parameters of adult male Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), change in response to food and water deprivation. Observations on the distance walked, the travel speed, and the frequency of walking bouts were carried out in laboratory arenas using motion monitoring equipment. Summer and overwintered beetles were exposed to short starvation periods (2, 4, 8, 24 h) and two ranges of long starvation periods (1, 2, 4, 8 days and 1, 2, 4, 8, 16, and 32 days). Only the longest food deprivation periods of 16 and 32 days significantly reduced the walking distance, speed, and frequency of walking bouts of summer beetles. No changes were observed with overwintered beetles. The tolerance of the beetles without access to water to the different periods of food deprivation was similar to that for beetles with water except after a starvation period of 32 days, when the travel speed of summer beetles was significantly reduced by 33%. The absence of increased walking parameters found in this study and earlier observations of increased flight frequency suggest that the strategy of summer beetles will be to change the dispersal mode from walking to flight and/or to change the walking host searching path. The same results of this study and earlier observations of a decrease in the mean frequency of daily flights suggest that the strategy of overwintered L. decemlineata, exposed to food deprivation, will be to change the host search walking path rather than the walking parameters themselves.     

OSBP-related protein 11 (ORP11) dimerizes with ORP9 and localizes at the Golgi-late endosome interface

We characterize here ORP11, a member of the oxysterol-binding protein family. ORP11 is present at highest levels in human ovary, testis, kidney, liver, stomach, brain, and adipose tissue. Immunohistochemistry demonstrates abundant ORP11 in the epithelial cells of kidney tubules, testicular tubules, caecum, and skin. ORP11 in HEK293 cells resides on Golgi complex and LE, co-localizing with GFP-Rab9, TGN46, GFP-Rab7, and a fluorescent medial-trans-Golgi marker. Under electron microscopic observation, cells overexpressing ORP11 displayed lamellar lipid bodies associated with vacuolar structures or the Golgi complex, indicating a disturbance of lipid trafficking. N-terminal fragment of ORP11 (aa 1-292) localized partially to Golgi, but displayed enhanced localization on Rab7- and Rab9-positive LE, while the C-terminal ligand-binding domain (aa 273-747) was cytosolic, demonstrating that the membrane targeting determinants are N-terminal. Yeast two-hybrid screen revealed interaction of ORP11 with the related ORP9. The interacting region was delineated within aa 98-372 of ORP9 and aa 154-292 of ORP11. Overexpressed ORP9 was able to recruit EGFP-ORP11 to membranes, and ORP9 silencing inhibited ORP11 Golgi association. The results identify ORP11 as an OSBP homologue distributing at the Golgi-LE interface and define the ORP9-ORP11 dimer as a functional unit that may act as an intracellular lipid sensor or transporter.     

Screening of Kozak-motif-located SNPs and analysis of their association with human diseases

The Kozak motif, which is located near the translational start codon, often regulates the protein translation. Moreover, it is believed that the conserved positions −3 and +4 contribute the most. Since changes that occur in this motif have a great impact on protein yield and in some cases are associated with disease, we screened the human SNP database for all Kozak-motif-located SNPs (kSNPs) and focused on the strong-changed kSNPs (sckSNPs). Many intron-located and synonymous SNPs are reported to be associated with disease, though the mechanisms underlying these associations are poorly understood. Here, we performed haplotype analysis on sckSNP-containing genes and found that there are some sckSNPs that exist in the same haplotype blocks of reported intron-located and synonymous disease-associated SNPs, indicating that those kSNPs could be a true risk factor for disease-association by affecting the efficiency of protein expression. Our findings provide a candidate explanation for how diseases are associated with intron-located and synonymous SNPs.     

Differential functions of genes regulated by VEGF-NFATc1 signaling pathway in the migration of pulmonary valve endothelial cells

We have reported that vascular endothelial growth factor (VEGF)-A induces the proliferation of human pulmonary valve endothelial cells (HPVECs) through nuclear factor in activated T cells (NFAT)c1 activation [1]. Here we show that VEGF-A increases the migration of HPVECs through NFATc1 activation, suggesting that VEGF-A/NFATc1 regulates the migration of HPVECs. To learn how this pathway may be involved in post-natal valvular repair, HPVECs were treated with VEGF-A, with or without cyclosporine A to selectively block VEGF-NFATc1 signaling. Down Syndrome critical region 1 (DSCR1) and heparin-binding EGF-like growth factor (HB-EGF) are two genes identified by DNA microarray as being up-regulated by VEGF-A in a cyclosporine-A-sensitive manner. DSCR1 silencing increased the migration of ovine valve endothelial cells, whereas HB-EGF silencing inhibited migration. This differential effect suggests that VEGF-A/NFATc1 signaling might be a crucial coordinator of endothelial cell migration in post-natal valves.     

Molecular determinants of the interactions between SRC-1 and LXR/RXR heterodimers

Liver X receptor (LXR)/retinoid X receptor (RXR) heterodimers have been shown to perform critical functions in cholesterol and lipid metabolism. Here, we have conducted a comparative analysis of the contributions of LXR and RXR binding to steroid receptor coactivator-1 (SRC-1), which contains three copies of the NR box. We demonstrated that the coactivator-binding surface of LXR, but not that of RXR, is critically important for physical and functional interactions with SRC-1, thereby confirming that RXR functions as an allosteric activator of SRC-1-LXR interaction. Notably, we identified NR box-2 and -3 as the essential binding targets for the SRC-1-induced stimulation of LXR transactivity, and observed the competitive in vitro binding of NR box-2 and -3 to LXR.

Structured summary

MINT-7986678, MINT-7986639, MINT-7986700, MINT-7986720, MINT-7986736, MINT-7986760, MINT-7986787: LXR (uniprotkb:Q13133) physically interacts (MI:0915) with SRC1 (uniprotkb:Q15788) and RXR (uniprotkb:P19793) by pull down (MI:0096)MINT-7986596, MINT-7986621: SRC1 (uniprotkb:Q15788) physically interacts (MI:0915) with LXR (uniprotkb:Q13133) by pull down (MI:0096)MINT-7986555, MINT-7986575: LXR (uniprotkb:Q13133) physically interacts (MI:0915) with SRC1 (uniprotkb:Q15788) by two hybrid (MI:0018)MINT-7986808, MINT-7986907, MINT-7986890: SRC1 (uniprotkb:Q15788) binds (MI:0407) to LXR (uniprotkb:Q13133) by pull down (MI:0096)MINT-7986822, MINT-7986848, MINT-7986865: SRC1 (uniprotkb:Q15788) binds (MI:0407) to RXR (uniprotkb:P19793) by pull down (MI:0096)