miR-128 Regulates Tumor Cell CD47 Expression and Promotes Anti-tumor Immunity in Pancreatic Cancer.

Pancreatic adenocarcinoma (PDAC) is a highly fatal disease worldwide. MicroRNAs (miRNAs) could regulate the protein-coding RNAs related to tumor growth, invasion, and immune evasion. Therefore, the investigation of novel miRNAs may be helpful in the development of more effective therapies for PDAC. In this study, we investigated the role and mechanism of action of miR-128 in PDAC. By using bioinformatics methods, we found that decreased expression of miR-128 was associated with poor overall survival of PDAC. miR-128 was inversely correlated with cluster of differentiation 47 (CD47), which was positively related to zinc finger E-box-binding homeobox 1 (ZEB1) in PDAC. Through in vivo experiments, we found that miR-128 could suppress the growth and metastasis of PDAC. Analysis of the immune microenvironment demonstrated that overexpression of miR-128 on tumor cells could increase the percentages of dendritic cells (DCs), CD8+ T lymphocytes, and natural killer T cells (NKT) in the tumor and spleen, consequently enhancing anti-tumor immunity. In vitro assays showed that miR-128 could inhibit cell proliferation, clonogenicity, migration, and invasion in Panc02 cells and could also enhance the phagocytosis of macrophages and the activity of DCs. Western blot and qRT-PCR confirmed that miR-128 could regulate ZEB1 and further inhibit CD47 in pancreatic cancer cells. Therefore, we identified a novel regulatory anti-tumor mechanism by miR-128 in PDAC, which may serve as a novel therapy for PDAC.

Effects of aging on time course of neovascularization-related gene expression following acute hindlimb ischemia in mice.

BACKGROUND: Molecular analysis of neovascularization related genes by time course in response to ischemia has not been described in the context of aging. We aimed to provide a progressively deeper understanding of how aging compromises neovascularization. METHODS: Young (3-month) and old (18-month) C57Bl mice were subjected to left hindlimb ischemia. Necrosis score was evaluated in calf muscles. Calf muscles, peripheral blood, bone marrow were harvested at different time points. The expressions of matrix metalloproteiniase-9 (MMP9), endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), stromal derived growth factor-1 (SDF1), hypoxia inducible factor-1α (HIF1α), VEGF receptor-1 (Flt1), VEGF receptor-2 (Flk1), angiopoietin-1 (Ang1), CD133, CD26 were detected by RT-PCR or Western blotting. White blood cells were counted in the peripheral blood. Gene expression data were compared by two-way analysis of variance. RESULTS: MMP9, HIF-1α and SDF-1 were more upregulated during acute ischemia in old vs. young mice, reflecting increased ischemia in aging mice. However VEGF and eNOS exhibited lower expression in old vs. young mice, despite greater ischemia intensity. Ang1 and Flk1 showed similar expression in old vs. young mice. MMP9 peaked earlier in peripheral blood in young vs. old mice. Concurrent decreasing CD26 and increasing CD133 expression in aging bone marrow suggest aging impairs progenitor cell mobilization, CONCLUSIONS: Our results indicate that a complex array of defects occur with aging that interfere with optimal neovascularization. These include potential impaired mobilization of progenitor cells to ischemic tissue, decreased levels of eNOS and VEGF and delayed responses to ischemia.

DNA Methylation in Genomes of Several Annual Herbaceous and Woody Perennial Plants of Varying Ploidy as Detected by MSAP.

Polyploidization is known to accompany altered DNA methylation in higher plants, which plays an important role in gene expression regulation and maintaining genome stability. While the characteristics of DNA methylation in different polyploid plants are still to be elucidated; here, status of genomic DNA methylation in a series of diploid, triploid, and tetraploid annual herbaceous plants (watermelon and Salvia) and woody perennials (pear, Poplar, and loquat) were explored by methylation-specific amplified polymorphism analysis. The results indicated that levels of DNA methylation in triploid watermelon and Salvia were lower than their diploid parents. In triploid Poplar and pear, higher levels of DNA methylation were detected, and no significant difference was observed between triploid and tetraploid in all tested materials. Further data analysis suggested that about half of the total detected sites underwent changes of DNA methylation patterns in triploid watermelons and Salvia, as well as an obvious trend towards demethylation. However, the changes of DNA methylation patterns in three triploid woody perennials were only 17.54-33.40%. This implied that the characteristics of DNA methylation are significantly different during the polyploidization of different plant species. Furthermore, the results suggested that the level of DNA methylation was nonlinearly related to the ploidy level, and triploid plants displayed more interesting DNA methylation status. The characteristics and possible functions of DNA methylation in different ploidy series are further discussed.

[Analysis of the level and pattern of genomic DNA methylation in different ploidy watermelons by MSAP (Citrullus lanatus)].

DNA methylation is one of the major epigenetic modifications. It is very important to the regulation of gene expression. In present study, an autoploidy series (2x, 3x and 4x) in watermelon (Citrullus lanatus) was constructed and MSAP (Methylation-Sensitive Amplification Polymorphism) analysis was conducted to elucidate the level and pattern of DNA methylation at CCGG sites in different ploidy watermelons. Totally, 1883 genetic loci were produced by 23 pairs of selective primers, of which 647, 655 and 581 sites were detected in diploid, autotriploid and autotetraploid, respectively. The methylation sites were 181, 150 and 159, and the corresponding total methylation ratios were 28.0%, 22.9% and 27.4% in 2x, 3x and 4x, respectively, of which the fully methylation sites were 121, 80 and 82, and the corresponding fully methylation ratios were 18.7%, 12.2% and 14.1%. Further analysis of the pattern of DNA methylation suggested that compared 4x with 2x, about half of detected sites (54.4%) shown changes of DNA methylation patterns. Similarly, compared 4x with 3x, 45.4% sites also shown changes of DNA methylation patterns. Moreover, the trend of DNA methylation adjustment mainly involved increase of DNA methylation levels in 4x. However, compared 3x with 2x or 4x, although the changes of DNA methylation pattern also widely occurred, which involved 41.6% (compared 3x with 2x) and 45.4% (compared 3x with 4x) sites, respectively, the trend of DNA methylation adjustment mainly involved decrease of DNA methylation levels in 3x. All these results indicated that DNA methylation events were widely existed in different ploidy watermelons. However, not only based on the total DNA methylation ratio or fully DNA methylation ratio, the results both implied that the DNA methylation levels were not closely associated with the autopolyploidy level in watermelon. Autotriploid watermelon shows obvious low level of DNA methylation. Analysis of DNA methylation patterns also suggested that the adjustment of DNA methylation patterns in autotriploid mainly involved demethylation events, implying the unusual characteristic of DNA methylation status in 3x watermelon. The present results are valuable to further explore the nature of triploid vigor and autopolyploidizaion in watermelon from the view of epigenetics.