Regulation of tumor cell migration and invasion by the H19/let-7 axis is antagonized by metformin-induced DNA methylation

The imprinted, developmentally regulated H19 long noncoding RNA has been implicated in the pathogenesis of diverse human cancers, but the underlying mechanisms have remained poorly understood. Here, we report that H19 promotes tumor cell migration and invasion by inhibiting let-7, a potent tumor suppressor microRNA that functions to posttranscriptionally suppress the expression of oncogenes that regulate cell growth and motility. We show that H19 depletion impairs, whereas its overexpression enhances the motility and invasiveness of tumor cells. These phenomena occur, at least in part through affecting let-7-mediated regulation of metastasis-promoting genes, including Hmga2, c-Myc and Igf2bp3. This H19/let-7-dependent regulation is recapitulated in vivo where co-expressions of oncogenes and H19 exist in both primary human ovarian and endometrial cancers. Furthermore, we provide evidence that the anti-diabetic drug metformin inhibits tumor cell migration and invasion, partly by downregulating H19 via DNA methylation. Our results reveal a novel mechanism underpinning H19-mediated regulation in metastasis and may explain why in some cases increased let-7 expression unexpectedly correlates with poor prognosis, given the widely accepted role for let-7 as a tumor suppressor. Targeting this newly identified pathway might offer therapeutic opportunities.

Transfection of hBMP-2 into mesenchymal stem cells derived from human umbilical cord blood and bone marrow induces cell differentiation into chondrocytes

AIM

Objective of the study was to compare the liposome-mediated transfection efficiency of the recombinant plasmid pIRES2-EGFP-hBMP-2 into mesenchymal stem cells (MSCs) derived from human umbilical cord blood (UCB-MSCs) and bone marrow (BM-MSCs).

METHODS

UCB-MSCs and BM-MSCs were isolated using density gradient centrifugation followed by adherent cultures. The plasmid (pIRES2-EGFP-hBMP-2) was transfected into MSCs by using X-treme GENE transfection kit. Successful transfection was determined by both the protein expression of EGFP observed by fluorescence microscopy and the mRNA expression of human bone morphogenetic protein-2 (hBMP-2) detected using RT-PCR. Cell surface marker and morphological changes were examined by immunohistochemistry (IHC) after two weeks of transfection.

RESULTS

Both UCB-MSCs and BM-MSCs were isolated and expanded successfully for multiple passages and demonstrated slight growth and morphological differences. The recombinant plasmid (pIRES2-EGFP-hBMP-2) was successfully transfected into both UCB-MSCs and BM-MSCs with an efficiency of 27.7 ± 7.6% and 18.4 ± 5.9%, respectively. The mRNA expression of hBMP-2 correlated with increased staining for collagen type II in the transfected cells.

CONCLUSION

Transfection of hBMP-2 in UCB-MSCs and BM-MSCs increases the expression of collagen type II. These results indicate that increased BMP-2 levels induce multipotent stem cell differentiation into chondrocytes.

Tumor resident mesenchymal stromal cells endow naïve stromal cells with tumor-promoting properties

Bone marrow mesenchymal stem/stromal cells (BM-MSCs) can infiltrate into tumors and subsequently evolve into tumor resident MSCs in tumor microenvironment. In this study, using a mouse lymphoma model, we showed that the lymphoma resident MSCs (L-MSCs) are able to confer tumor-promoting property to the naïve cocultured BM-MSCs. Examination of cytokines and chemokines showed that post exposure to L-MSCs, BM-MSCs acquired an expression profile that is similar to that in L-MSCs. In vivo, BM-MSCs educated by L-MSCs (BM-L-MSCs) possess a greatly enhanced ability in promoting lymphoma growth. Consistent with an elevated CCL-2 expression in BM-L-MSCs, the tumor-promoting effect of BM-L-MSCs largely depends on CCR2-mediated macrophage recruitment to tumor sites. We further showed that the transmission of tumor-promoting effect is partially mediated by soluble factors. Our findings thus revealed a novel reinforcing mechanism in the maintenance of tumor microenvironment.

First Report of Fusarium tricinctum Causing Stem and Root Rot on Lanzhou Lily (Lilium davidii var. unicolor) in China

Lanzhou lily (Lilium davidii var. unicolor Cotton) is an important bulb edible crop which mostly distributes in middle area of Gansu Province in China (2). Recently, plants of Lanzhou lily developed symptoms of severe wilting. In early autumn of 2012 to 2013, a survey of Lanzhou lily disease was carried out in Yuanjiawan, Caoyuan, Xiguoyuan, and Hutan villages of Lanzhou City and Xuding and Guanshan villages of Linxia Prefecture. Disease symptoms included stem and root rot, vessels showed a brown to dark brown discoloration, plus a progressive yellowing and wilting of leaves from the base. Small pieces of symptomatic leaves, stems, and roots were surface disinfected with 75% ethanol for 30 s, 3% sodium hypochlorite for 5 min, and then washed three times in sterile distilled water. The tissues were placed on Martin Agar at 25°C for 7 days. Three isolates were consistently isolated from diseased tissues and all isolates with morphology similar to Fusarium spp. Isolates were transferred to potato dextrose agar (PDA) and carnation leaf agar (CLA) and incubated at 25°C in darkness. These isolates grew rapidly on PDA and formed abundant dense aerial mycelium, initially white, that became deep pink with age and formed red pigments in the medium. On CLA, macroconidia with 3 to 5 septa were abundant, relatively slender, and curved to lunate. Microconidia were abundant, oval and 0 to 1 septa. Chlamydospores were globose with a smooth outer wall in chains. The rDNA internal transcribed spacer (ITS) region comprising ITS1, ITS2, and 5.8S rDNA was amplified using primers ITS-1 and ITS-4 (3) and sequenced. On the basis of a comparison of 563 bp, all the three isolates had the identical sequence (GenBank Accession No. KF728675). BLASTn analysis of the sequence showed 100% match with the ITS sequences of those F. tricinctum sequences in GenBank (Accession Nos. FJ233196, AY188923, and JF776663). Pathogenicity test was performed by transplanting 2-month-old tissue culture seedlings to plastic pots in a sterile mixture of vermiculite and torf substrate at 1:3 (v/v). Seedlings were inoculated with 6 ml of the conidial suspension (10⁴ conidia/ml) on the roots of plant in each pot, three plants per pot, and three replicates for each treatment. Seedlings treated with sterile water served as controls. The seedlings were placed in a plant growth chamber maintained at 22 ± 3°C, relative humidity >70%, 16 h light per day, and irrigated with sterile water. After 4 weeks, inoculated plants exhibited wilting foliage that with symptoms similar to those observed in the field, while the control plants remained healthy. F. tricinctum was re-isolated from all inoculated plants. The disease has been reported previously in ornamental lily in China (1). However, to the best of our knowledge, this is the first report of F. tricinctum causing wilt on edible Lanzhou lily in China and the disease must be taken into consideration of current disease management. This work supported by NSFC No. 31370447 and Hundred Talents Program of CAS "Molecular mechanism of biological control on plant diseases." References: (1) Y. Y. Li et al. Plant Dis. 97:993, 2013. (2) R. Y. Wang et al. Virol. J. 7:34, 2010. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

Genetic tuning of the novel avian influenza A(H7N9) virus during interspecies transmission, China, 2013

A novel avian influenza A(H7N9) virus causing human infection emerged in February 2013 in China. To elucidate the mechanism of interspecies transmission, we compared the signature amino acids of avian influenza A(H7N9) viruses from human and non-human hosts and analysed the reassortants of 146 influenza A(H7N9) viruses with full genome sequences. We propose a genetic tuning procedure with continuous amino acid substitutions and reassorting that mediates host adaptation and interspecies transmission. When the early influenza A(H7N9) virus, containing ancestor haemagglutinin (HA) and neuraminidase (NA) genes similar to A/Shanghai/05 virus, circulated in waterfowl and transmitted to terrestrial poultry, it acquired an NA stalk deletion at amino acid positions 69 to 73. Then, receptor binding preference was tuned to increase the affinity to human-like receptors through HA G186V and Q226L mutations in terrestrial poultry. Additional mammalian adaptations such as PB2 E627K were selected in humans. The continual reassortation between H7N9 and H9N2 viruses resulted in multiple genotypes for further host adaptation. When we analysed a potential association of mutations and reassortants with clinical outcome, only the PB2 E627K mutation slightly increased the case fatality rate. Genetic tuning may create opportunities for further adaptation of influenza A(H7N9) and its potential to cause a pandemic.

Interleukin-37 ameliorates myocardial ischaemia/reperfusion injury in mice

Innate immune and inflammatory responses are involved in myocardial ischaemia/reperfusion (I/R) injury. Interleukin (IL)-37 is a newly identified member of the IL-1 family, and functions as a fundamental inhibitor of innate immunity and inflammation. However, its role in myocardial I/R injury remains unknown. I/R or sham operations were performed on male C57BL/6J mice. I/R mice received an injection of recombinant human IL-37 or vehicle, immediately before reperfusion. Compared with vehicle treatment, mice treated with IL-37 showed an obvious amelioration of the I/R injury, as demonstrated by reduced infarct size, decreased cardiac troponin T level and improved cardiac function. This protective effect was associated with the ability of IL-37 to suppress production of proinflammatory cytokines, chemokines and neutrophil infiltration, which together contributed to a decrease in cardiomyocyte apoptosis and reactive oxygen species (ROS) generation. In addition, we found that IL-37 inhibited the up-regulation of Toll-like receptor (TLR)-4 expression and nuclear factor kappa B (NF-kB) activation after I/R, while increasing the anti-inflammatory IL-10 level. Moreover, the administration of anti-IL-10R antibody abolished the protective effects of IL-37 in I/R injury. In-vitro experiments further demonstrated that IL-37 protected cardiomyocytes from apoptosis under I/R condition, and suppressed the migration ability of neutrophils towards the chemokine LIX. In conclusion, IL-37 plays a protective role against mouse myocardial I/R injury, offering a promising therapeutic medium for myocardial I/R injury.

Nuclear CSPP1 expression defined subtypes of basal-like breast cancer

BACKGROUND

The multi-exon CSPP1 gene, encoding for centrosome and microtubule-associated proteins involved in ciliogenesis and cell division, is a candidate oncogene in luminal breast cancer but expression of CSPP1 proteins remained unexplored.

METHODS

CSPP1 gene and protein expression was examined in normal mammary tissue, human breast cancer cell lines, and primary breast cancer biopsies from two patient cohorts. Cell type and epitope-dependent subcellular-specific CSPP1 staining pattern in normal mammary gland epithelium and cancer biopsies were correlated to molecular and clinical parameters.

RESULTS

A novel, nuclear localised CSPP1 isoform was exclusively detected in luminal epithelial cells, whereas cytoplasmic CSPP-L was generally expressed in normal mammary epithelium. Luminal cell-related nuclear CSPP1 expression was preserved in type-matched cell lines and carcinomas, and correlated to gene copy number and mRNA expression. In contrast, basal-like carcinomas displayed generally lower CSPP1 mRNA expression. Yet, a subgroup of basal-like breast carcinomas depicted nuclear CSPP1 expression, displayed luminal traits, and differed from nuclear CSPP1 devoid counterparts in expression of eight genes. Eight-gene signature defined groups of basal-like tumours from an independent cohort showed significant differences in survival.

CONCLUSIONS

Differential expression of a nuclear CSPP1 isoform identified biologically and clinically distinct subgroups of basal-like breast carcinoma.

Effects of feed restriction and prolactin-release inhibition at drying off on metabolism and mammary gland involution in cows

A cow's risk of acquiring a new intramammary infection during the dry period increases with milk production at drying off and decreases as mammary gland involution progresses. A method commonly used to reduce milk production is a drastic reduction in feed supply in the days that precede drying off. Milk production can also be reduced by inhibiting the lactogenic signal driven by prolactin (PRL). This study aimed to compare the effects of these 2drying-off procedures on metabolism, immunity, and mammary gland involution in cows. A total of 24Holstein cows in late lactation were assigned to 1 of 3treatments based on milk yield, somatic cell count, and parity. The cows were fed a lactation diet until drying off (control; n=8), only dry hay during the last 5d before drying off (DH; n=8), or the same lactation diet as the control cows but with twice-daily i.m. injections of 4mg of quinagolide, a specific inhibitor of PRL release, from 5d before drying off until 13d after (QN; n=8). Quinagolide induced a decrease in PRL concentration in blood and in milk and mammary secretions on all the injection days. Interestingly, PRL was also depressed in the blood and milk of the hay-fed cows before drying off. Both the QN and DH treatments induced a decrease in milk production, which averaged 17.9 and 10.1kg/d for the QN and DH cows, respectively, at drying off in comparison with 24.8kg/d for the control cows. Both BSA concentration and Na(+)-to-K(+) ratio increased faster in the mammary secretions of both the DH and QN cows than in those of the control cows, whereas citrate-to-lactoferrin ratio, another indicator of involution rate, decreased faster. The DH treatment decreased blood concentrations of glucose and most amino acids and increased blood concentrations of β-hydroxybutyrate and nonesterified fatty acids. Quinagolide increased blood glucose but did not affect the other metabolites. The serum harvested on d-1 from the hay-fed cows reduced peripheral blood mononuclear cell proliferation and IL-4 production, whereas the serum from the quinagolide-treated cows had no effect. In conclusion, this experiment shows that PRL-release inhibition could be a new alternative for reducing milk production before drying off and for hastening mammary gland involution without disturbing the metabolism of the cow.

Amelioration of Muc5b mucin hypersecretion is enhanced by IL-33 after 2-APB administration in a murine model of allergic rhinitis

We attempted to clarify whether hypersecretion of Muc5b mucin from mouse nasal submucosal glands that is enhanced by interleukin (IL)-33 under allergic conditions can be ameliorated by administration of 2-APB. Immunohistochemistry was used to examine both the distribution of T cells in the nasal mucosa of an allergic rhinitis mouse model and expressions of IL-33 receptor ST2 and Muc5b protein in mouse submucosal gland cells. The amounts of protein and mRNA of Orai1, Muc5b, IL-4, IL-5, IL-13 and IL-33 in mouse nasal lavage fluid (NLF) and nasal mucosa were determined using enzyme-linked immunosorbent assay and real-time reverse transcription-polymerase chain reaction. Expressions of Orai1, Muc5b, IL-4, IL-5, IL-13 and IL-33 were up-regulated in the allergic state and IL-33 increased the levels of Muc5b, IL-4, IL-5 and IL-13, but did not influence proliferation of T cells; however, ST2 was diminished in nasal submucosal gland cells. 2-APB reduced proliferation of T cells and the Orai1 level in the nasal mucosa. It also reduced the concentrations of IL-4, IL-5 and IL-13 in NLF and nasal mucosa, and hypersecretion of Muc5b from glandular cells that was enhanced by IL-33, but did not affect IL-33 production. 2-APB decreased Muc5b mucin hypersecretion from submucosal gland that was enhanced by IL-33 in allergic mice by limiting Ca(2+) release-activated Ca(2+) channel activity in which Orai1 plays a crucial role in the gland cells and/or by controlling channel activation in T cells and proliferation of these cells.

Automatic localization of the left ventricle from cardiac cine magnetic resonance imaging: a new spectrum-based computer-aided tool

Traditionally, cardiac image analysis is done manually. Automatic image processing can help with the repetitive tasks, and also deal with huge amounts of data, a task which would be humanly tedious. This study aims to develop a spectrum-based computer-aided tool to locate the left ventricle using images obtained via cardiac magnetic resonance imaging. Discrete Fourier Transform was conducted pixelwise on the image sequence. Harmonic images of all frequencies were analyzed visually and quantitatively to determine different patterns of the left and right ventricles on spectrum. The first and fifth harmonic images were selected to perform an anisotropic weighted circle Hough detection. This tool was then tested in ten volunteers. Our tool was able to locate the left ventricle in all cases and had a significantly higher cropping ratio of 0.165 than did earlier studies. In conclusion, a new spectrum-based computer aided tool has been proposed and developed for automatic left ventricle localization. The development of this technique, which will enable the automatic location and further segmentation of the left ventricle, will have a significant impact in research and in diagnostic settings. We envisage that this automated method could be used by radiographers and cardiologists to diagnose and assess ventricular function in patients with diverse heart diseases.

Chickens from lines artificially selected for juvenile low and high body weight differ in glucose homeostasis and pancreas physiology

Artificial selection of White Plymouth Rock chickens for juvenile (day 56) body weight resulted in two divergent genetic lines: hypophagic low weight (LWS) chickens and hyperphagic obese high weight (HWS) chickens, with the latter more than 10-fold heavier than the former at selection age. A study was designed to investigate glucose regulation and pancreas physiology at selection age in LWS chickens and HWS chickens. Oral glucose tolerance and insulin sensitivity tests revealed differences in threshold sensitivity to insulin and glucose clearance rate between the lines. Results from real-time PCR showed greater pancreatic mRNA expression of four glucose regulatory genes (preproinsulin, PPI; preproglucagon, PPG; glucose transporter 2, GLUT2; and pancreatic duodenal homeobox 1, Pdx1) in LWS chickens, than HWS chickens. Histological analysis of the pancreas revealed that HWS chickens have larger pancreatic islets, less pancreatic islet mass, and more pancreatic inflammation than LWS chickens, all of which presumably contribute to impaired glucose metabolism.