CircATXN7 contributes to the progression and doxorubicin resistance of breast cancer via modulating miR-149-5p/HOXA11 pathway.

Breast cancer is a frequent tumor threatening the health of women. Circular RNAs (circRNAs) play vital roles in cancer progression and chemoresistance. Herein, we mainly investigate the role and potential mechanism of circRNA ataxin 7 (circATXN7; circ_0066436) in breast cancer. RNA expression levels were detected via quantitative real-time PCR (qPCR), western blot and immunohistochemistry. Cell viability and half inhibitory concentration (IC50) of doxorubicin were assessed by cell counting kit-8 (CCK-8) method. Cell proliferation, migration and invasion were determined by CCK-8, 5-ethynyl-2'-deoxyuridine, colony formation and transwell assays. The binding relationship between microRNA-149-5p (miR-149-5p) and circATXN7 or homeobox A11 (HOXA11) was validated via dual-luciferase reporter assay and RNA immunoprecipitation assay. Xenograft assay was conducted to analyze the effect of circATXN7 on doxorubicin resistance of breast cancer. CircATXN7 and HOXA11 levels were enhanced, whereas miR-149-5p level was declined in breast cancer tissues and cells. CircATXN7 silencing suppressed breast cancer development and doxorubicin resistance. Additionally, circATXN7 upregulated HOXA11 via absorbing miR-149-5p, thereby inducing breast cancer cell progression and reducing doxorubicin sensitivity. Besides, depletion of circATXN7 enhanced doxorubicin sensitivity in vivo. Interference of circATXN7 inhibited breast cancer progression and doxorubicin resistance via mediating miR-149-5p/HOXA11 axis, which might provide a possible biomarker for breast cancer therapy.

Human miRNA miR-675 inhibits DUX4 expression and may be exploited as a potential treatment for Facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is a potentially devastating myopathy caused by de-repression of the DUX4 gene in skeletal muscles. Effective therapies will likely involve DUX4 inhibition. RNA interference (RNAi) is one powerful approach to inhibit DUX4, and we previously described a RNAi gene therapy to achieve DUX4 silencing in FSHD cells and mice using engineered microRNAs. Here we report a strategy to direct RNAi against DUX4 using the natural microRNA miR-675, which is derived from the lncRNA H19. Human miR-675 inhibits DUX4 expression and associated outcomes in FSHD cell models. In addition, miR-675 delivery using gene therapy protects muscles from DUX4-associated death in mice. Finally, we show that three known miR-675-upregulating small molecules inhibit DUX4 and DUX4-activated FSHD biomarkers in FSHD patient-derived myotubes. To our knowledge, this is the first study demonstrating the use of small molecules to suppress a dominant disease gene using an RNAi mechanism.

Cisplatin decreases HOXA13 and alphaVBeta3 integrin levels in the uterus.

OBJECTIVE: To examine the effects of cisplatin on uterine histology and implantation molecules and the possible protective role of recombinant Klotho administration on uterine histology and uterine receptivity in mice exposed to cisplatin. MATERIALS AND METHODS: This study was conducted using thirty-two adult female mice assigned to four groups with 8 mice in each group. Saline was given to the 1st group, cisplatin to the 2nd group, recombinant mouse Klotho to the 3rd group and recombinant mouse Klotho plus cisplatin to the 4th group. Uterine tissues were examined for damage histologically and immunobiologically for the uterine receptivity markers HOXA13 and alphaVBeta3 integrin. RESULTS: Apoptosis, degeneration, decrease in uterine thickness and uterine absence of gland scores were higher in the cisplatin group (3rd group) compared to the saline group (1st group) (cisplatin vs. saline p < 0.0001 for all parameters). In the recombinant Klotho plus cisplatin group (4th group), scores of apoptosis, degeneration, reduction in uterine thickness and uterine absence of gland were lower than the group receiving only cisplatin (cisplatin plus recombinant Klotho vs cisplatin, p = 0.006 for apoptosis; p = 0.017 for degeneration; p = 0.011 for the reduction in uterine thickness; p = 0.002 for the absence of gland). However, HOXA13 and alphaVBeta3 integrin staining levels were not different between the cisplatin group (group 3) and the cisplatin plus recombinant Klotho group (group 4) (p = 0.980 and p = 0.762, respectively.) CONCLUSION: Cisplatin has adverse effects on the uterus. Administration of recombinant Klotho was found to attenuate the cisplatin-induced damage but failed to preserve levels of the implantation molecules HOXA13 and alphaVbeta3. Further studies examining the effect of cisplatin toxicity using other implantation markers along with functional studies are needed.

Cardioprotective Effects of Dietary Flaxseed Post-Infarction Are Associated with Changes in MicroRNA Expression.

MicroRNAs (miRNAs/miRs) such as miR-1, miR-133a, miR-133b, miR-135a, and miR-29b play a key role in many cardiac pathological remodeling processes, including apoptosis, fibrosis, and arrhythmias, after a myocardial infarction (MI). Dietary flaxseed has demonstrated a protective effect against an MI. The present study was carried out to test the hypothesis that dietary flaxseed supplementation before and after an MI regulates the expression of above-mentioned miRNAs to produce its cardioprotective effect. Animals were randomized after inducing MI by coronary artery ligation into: (a) sham MI with normal chow, (b) MI with normal chow, and (c-e) MI supplemented with either 10% milled flaxseed, or 4.4% flax oil enriched in alpha-linolenic acid (ALA), or 0.44% flax lignan secoisolariciresinol diglucoside. The feeding protocol consisted of 2 weeks before and 8 weeks after the surgery. Dietary flax oil supplementation selectively upregulated the cardiac expression of miR-133a, miR-135a, and miR-29b. The levels of collagen I expression were reduced in the flax oil group. We conclude that miR-133a, miR-135a, and miR-29b are sensitive to dietary flax oil, likely due to its rich ALA content. The cardioprotective effect of flaxseed in an MI could be due to modulation of these miRNAs.

Nicotine inhibits expression of Prrx1 in pituitary stem/progenitor cells through epigenetic regulation, leading to a delayed supply of growth-hormone-producing cells.

OBJECTIVE: Nicotine, a toxic component of smoking, adversely affects animal growth and reproduction by decreasing secretion of anterior pituitary hormones. However, it has not been clarified whether nicotine inhibits the supply of endocrine cells in the pituitary gland. The present study investigated short- and long-term effects of persistent nicotine exposure on the pituitary glands of young animals. DESIGN: Three-week-old male Wistar rats were exposed to nicotine (1 mg/kg body weight/day) for 7 days, and gene expression, cell numbers, and DNA methylation status were analyzed on the following day and 4 weeks after final treatments. RESULTS: The expression level of the stem cell marker Sox2 was not changed by nicotine exposure throughout the experiment. On the other hand, nicotine inhibited expression of a progenitor cell marker, Prrx1, and growth hormone (Gh). Immunohistochemical analysis showed that the SOX2-positive cells positive for PRRX1 in nicotine-treated groups decreased to 61% (4-week-old) and 70% (8-week-old) of the saline-treated controls. In addition, the proportion of GH-positive cells in nicotine-treated group was 14% lower than that of saline-treated controls. Furthermore, first intron hypermethylation of Prrx1 was detected by a bisulfite sequence of genomic DNA from the anterior lobe of the rat pituitary gland. CONCLUSIONS: We show that persistent nicotine exposure in young animals inhibits expression of Prrx1 in pituitary stem/progenitor cells through epigenetic regulation, leading to a delayed supply of GH-producing cells.

Peptidomic analysis of hippocampal tissue for explore leptin neuroprotective effect on the preterm ischemia-hypoxia brain damage model rats.

The most common injury of preterm infants is periventricular leukomalacia (PVL) and to date there is still no safe and effective treatment. In our previous studies, leptin has been found to have neuroprotective effects on the preterm ischemia-hypoxia brain damage model rats in animal behavior. To gain insight into the neuroprotective mechanisms of leptin on preterm brain damage model rats, we constructed a comparative peptidomic profiling of hippocampal tissue between leptin-treated after model and preterm ischemia-hypoxia brain damage model rats using a stable isobaric labeling strategy involving tandem mass tag reagents, followed by nano liquid chromatography tandem mass spectrometry. We identified and quantified 4164 peptides, 238 of which were differential expressed in hippocampal tissue in the two groups. A total of 150 peptides were up regulated and 88 peptides were down regulated. These peptides were imported into the Ingenuity Pathway Analysis (IPA) and identified putative roles in nervous system development, function and diseases. We concluded that the preterm ischemia-hypoxia brain damage model with leptin treatment induced peptides changes in hippocampus, and these peptides, especially for the peptides associated "microtubule-associated protein 1b (MAP1b), Elastin (Eln), Piccolo presynaptic cytomatrix protein (Pclo), Zinc finger homeobox 3(Zfhx3), Alpha-kinase 3(Alpk3) and Myosin XVA(Myo15a) ", could be candidate bio-active peptides and participate in neuroprotection of leptin. These may advance our current understanding of the mechanism of leptin's neuroprotective effect on preterm brain damage and may be involved in the etiology of preterm brain damage. Meanwhile, we found that repression of ILK signaling pathway plays a significant role in neuroprotection of leptin. A better understanding of the role of ILK signaling pathway in neuroprotective mechanisms will help scientists and researchers to develop selective, safe and efficacious drug for therapy against human nervous system disorders.

Early Growth Hormone Intervention Improves Glucose Metabolism in Adult Rats Born Small for Gestational Age.

BACKGROUND: Small for gestational age (SGA) due to intrauterine malnourishment is closely related to metabolic syndrome and type 2 diabetes mellitus. Growth Hormone (GH) treatment has been demonstrated to influence metabolic parameters and islet function of SGA individuals. The present study demonstrates the effects of early GH treatment on glucose tolerance and expression of pancreatic duodenal homeobox 1 (Pdx1) of SGA rats during adulthood. METHODS: SGA rat model was induced by restricting food intake during pregnancy. GH or normal saline was administered during postnatal days 21-35 of SGA rats and appropriate for gestational age (AGA) rats, respectively. RESULTS: In early adulthood (postnatal day 70), as compared to AGA rats, SGA rats showed: (1) decreased body weight; (2) increased postprandial blood glucose; and (3) down-regulated Pdx1 with increased histone deacetylase (HDAC) and down-regulated histone H3-lysine 4 methyltransferase SET7/9. Exogenous GH administration led to a restoration of body weight and normalized glucose tolerance due to an enhanced Pdx1 expression, accompanied by decreased HDAC and up-regulated SET7/9 in SGA rats in early adulthood. CONCLUSION: Our results demonstrate positive effects on glucose metabolism by an early and short GH treatment in SGA adulthood.

Knockdown of HOXB8 inhibits tumor growth and metastasis by the inactivation of Wnt/ß-catenin signaling pathway in osteosarcoma.

Homeobox B8 (HOXB8) is a member of HOX family and was reported to be dysregulated in human cancers. However, its expression pattern and function in human osteosarcoma (OS) remain unknown. The aim of the current study is to examine its expression and biological roles in human OS cells. Our results showed that HOXB8 was highly expressed in human OS tissues and cell lines. Knockdown of HOXB8 significantly suppressed the proliferation of OS cells in vitro and attenuated the tumor growth in a tumor xenograft model. In addition, knockdown of HOXB8 dramatically repressed the migration and invasion of OS cells. Furthermore, knockdown of HOXB8 efficiently prevented the activation of Wnt/ß-catenin signaling pathway in OS cells. In conclusion, the findings of the present study demonstrated that knockdown of HOXB8 could suppress tumorigenesis and metastasis in OS through regulation of the Wnt/ß-catenin signaling pathway. Thus, HOXB8 may represent a novel therapeutic target for the treatment of OS.

Glucose-Induced ß-Cell Dysfunction In Vivo: Evidence for a Causal Role of C-jun N-terminal Kinase Pathway.

Prolonged elevation of glucose can adversely affect ß-cell function. Oxidative stress, which has been implicated in glucose-induced ß-cell dysfunction, can activate c-jun N-terminal kinase (JNK). However, whether JNK is causal in glucose-induced ß-cell dysfunction in vivo is unclear. Therefore, we aimed at investigating the causal role of JNK activation in in vivo models of glucose-induced ß-cell dysfunction. Glucose-induced ß-cell dysfunction was investigated in the presence or absence of JNK inhibition. JNK inhibition was achieved using either (i) the JNK-specific inhibitor SP600125 or (ii) JNK-1-null mice. (i) Rats or mice were infused intravenously with saline or glucose with or without SP600125. (ii) JNK-1 null mice and their littermate wild-type controls were infused intravenously with saline or glucose. Following the glucose infusion periods in rats and mice, ß-cell function was assessed in isolated islets or in vivo using hyperglycemic clamps. Forty-eight-hour hyperglycemia at ~20 mM in rats or 96-hour hyperglycemia at ~13 mM in mice impaired ß-cell function in isolated islets and in vivo. Inhibition of JNK using either SP600125 or JNK-1-null mice prevented glucose-induced ß-cell dysfunction in isolated islets and in vivo. Islets of JNK-1-null mice exposed to hyperglycemia in vivo showed an increase in Pdx-1 and insulin 2 mRNA, whereas islets of wild-type mice did not. Together, these data show that JNK pathway is involved in glucose-induced ß-cell dysfunction in vivo and is thus a potential therapeutic target for type 2 diabetes.

Direct Reprogramming of Glioblastoma Cells into Neurons Using Small Molecules.

Glioblastoma multiforme, a type of deadly brain cancer, originates most commonly from astrocytes found in the brain. Current multimodal treatments for glioblastoma minimally increase life expectancy, but significant advancements in prognosis have not been made in the past few decades. Here we investigate cellular reprogramming for inhibiting the aggressive proliferation of glioblastoma cells. Cellular reprogramming converts one differentiated cell type into another type based on the principles of regenerative medicine. In this study, we used cellular reprogramming to investigate whether small molecule mediated reprogramming could convert glioblastoma cells into neurons. We investigated a novel method for reprogramming U87MG human glioblastoma cells into terminally differentiated neurons using a small molecule cocktail consisting of forskolin, ISX9, CHIR99021 I-BET 151, and DAPT. Treating U87MG glioblastoma cells with this cocktail successfully reprogrammed the malignant cells into early neurons over 13 days. The reprogrammed cells displayed morphological and immunofluorescent characteristics associated with neuronal phenotypes. Genetic analysis revealed that the chemical cocktail upregulates the Ngn2, Ascl1, Brn2, and MAP2 genes, resulting in neuronal reprogramming. Furthermore, these cells displayed decreased viability and lacked the ability to form high numbers of tumor-like spheroids. Overall, this study validates the use of a novel small molecule cocktail for reprogramming glioblastoma into nonproliferating neurons.

Liuwei Dihuang pill cures postmenopausal osteoporosis with kidney-Yin deficiency: Potential therapeutic targets identified based on gene expression profiling.

This study aimed to investigate the potential therapeutic targets of Liuwei Dihuang pill (LDP) in the treatment of postmenopausal osteoporosis with kidney-Yin deficiency (PMO-KY).Gene expression data were downloaded from the GEO database, including 4 PMO-KY samples and 3 healthy postmenopausal controls from GSE56116, as well as 3 PMO-KY samples before LDP treatment and 3 PMO-KY samples after three months of LDP treatment from GSE57273. Limma package was used to identify differentially expressed genes (DEGs). Afterwards, the potential target genes of LDP (namely key DEGs) were identified according to the comparison of DEGs in PMO-KY group and the DEGs in LDP treatment groups. Subsequently, iRegulon plugin in Cytoscape software was used to predict potential transcription factors (TFs) that regulated the key DEGs, and Comparative Toxicogenomics Database was utilized to identify known PMO-related genes among the key DEGs.Totally, 202 and 2066 DEGs were identified between PMO-KY and controls, as well as after-treatment and before-treatment groups, respectively. Among them, 52 DEGs were up-regulated in PMO-KY but down-regulated after LDP treatment, and 8 TFs were predicted to these DEGs. Furthermore, 34 DEGs were down-regulated in PMO-KY but up-regulated after treatment, and 7 TFs were predicted to regulate these DEGs. Additionally, 43 of the 86 key DEGs were known PMO-related genes.NCOA3, TCF4, DUSP6, PELI2, and STX7 were predicted to be regulated by HOXA13. In the PMO-KY treatment, NCOA3, TCF4, DUSP6, PELI2, and STX7 might be the potential therapeutic targets of LDP. However, further investigation is required to confirm these genes.

Desogestrel down-regulates PHOX2B and its target genes in progesterone responsive neuroblastoma cells.

The paired-like homeobox 2B gene (PHOX2B) encodes a key transcription factor that plays a role in the development of the autonomic nervous system and the neural structures involved in controlling breathing. In humans, PHOX2B over-expression plays a role in the pathogenesis of tumours arising from the sympathetic nervous system such as neuroblastomas, and heterozygous PHOX2B mutations cause Congenital Central Hypoventilation Syndrome (CCHS), a life-threatening neurocristopathy characterised by the defective autonomic control of breathing and involving altered CO2/H+ chemosensitivity. The recovery of CO2/H+ chemosensitivity and increased ventilation have been observed in two CCHS patients using the potent contraceptive progestin desogestrel. Given the central role of PHOX2B in the pathogenesis of CCHS, and the progesterone-mediated effects observed in the disease, we generated progesterone-responsive neuroblastoma cells, and evaluated the effects of 3-Ketodesogestrel (3-KDG), the biologically active metabolite of desogestrel, on the expression of PHOX2B and its target genes. Our findings demonstrate that, through progesterone nuclear receptor PR-B, 3-KDG down-regulates PHOX2B gene expression, by a post-transcriptional mechanism, and its target genes and open up the possibility that this mechanism may contribute to the positive effects observed in some CCHS patients.

Selective DOT1L, LSD1, and HDAC Class I Inhibitors Reduce HOXA9 Expression in MLL-AF9 Rearranged Leukemia Cells, But Dysregulate the Expression of Many Histone-Modifying Enzymes.

Mixed lineage leukemia results from chromosomal rearrangements of the gene mixed lineage leukemia (MLL). MLL-AF9 is one such rearrangement that recruits the lysine methyltransferase, human disruptor of telomere silencing 1-like (DOT1L) and lysine specific demethylase 1 (LSD1), resulting in elevated expression of the Homeobox protein A9 (HOXA9), and leukemia. Inhibitors of LSD1 or DOT1L reduce HOXA9 expression, kill MLL-rearranged cells, and may treat leukemia. To quantify their effects on histone modifying enzyme activity and expression in MLL-rearranged leukemia, we tested inhibitors of DOT1L (EPZ-5676), LSD1 (GSK2879552), and HDAC (mocetinostat), in the MLL-AF9 cell line MOLM-13. All inhibitors reduced MOLM-13 viability but only mocetinostat induced apoptosis. EPZ-5676 increased total histone lysine dimethylation, which was attributed to a reduction in LSD1 expression, and was indistinguishable from direct LSD1 inhibition by GSK2879552. All compounds directly inhibit, or reduce the expression of, HOXA9, DOT1L and LSD1 by qPCR, increase total histone lysine methylation and acetylation by LC-MS/MS, and specifically reduce H3K79Me2 and increase H3K14Ac. Each inhibitor altered the expression of many histone modifying enzymes which may precipitate additional changes in expression. To the extent that this decreases HOXA9 expression it benefits mixed lineage leukemia treatment, all other expression changes are off-target effects.

The promotion on cell growth of androgen-dependent prostate cancer by antimony via mimicking androgen activity.

Antimony is a widely used heavier pnictogens in industry, and its toxicity has been a matter of concern. Although previous studies have suggested that antimony may have the function as either a tumor suppressor or an oncogene in several cancers, the molecular basis underlying antimony-mediated transformation is still unclear. In the current study, we attempt to elucidate the potential role of antimony in the development of prostate cancer. Our results showed that the concentration of antimony was much higher in serum of prostate cancer patients, and was closely associated with poor outcome of patients who underwent radical prostatectomy. Additionally, low dose of antimony could promote proliferation and invasion of androgen-dependent prostate cancer cell line LNCaP cells in vitro and in vivo. The mechanistic studies demonstrated that exposure to antimony triggered the phosphorylation of androgen receptor (AR), which transcriptionally regulates the expression of androgen-related targets, including PSA and NKX3.1. Overall, our results unearthed that antimony could promote tumor growth by mimicking androgen activity in androgen-dependent prostate cancer cells. Therefore, these findings expanded our understanding on the molecular mechanism of antimony in tumorigenesis and tumor progression of prostate cancer, and it appears to be an inspiring strategy to restrain prostate cancer by inhibiting antimony-induced androgen-like effects.

Profound hyperglycemia in knockout mutant mice identifies novel function for POU4F2/Brn-3b in regulating metabolic processes.

The POU4F2/Brn-3b transcription factor has been identified as a potentially novel regulator of key metabolic processes. Loss of this protein in Brn-3b knockout (KO) mice causes profound hyperglycemia and insulin resistance (IR), normally associated with type 2 diabetes (T2D), whereas Brn-3b is reduced in tissues taken from obese mice fed on high-fat diets (HFD), which also develop hyperglycemia and IR. Furthermore, studies in C2C12 myocytes show that Brn-3b mRNA and proteins are induced by glucose but inhibited by insulin, suggesting that this protein is itself highly regulated in responsive cells. Analysis of differential gene expression in skeletal muscle from Brn-3b KO mice showed changes in genes that are implicated in T2D such as increased glycogen synthase kinase-3ß and reduced GLUT4 glucose transporter. The GLUT4 gene promoter contains multiple Brn-3b binding sites and is directly transactivated by this transcription factor in cotransfection assays, whereas chromatin immunoprecipitation assays confirm that Brn-3b binds to this promoter in vivo. In addition, correlation between GLUT4 and Brn-3b in KO tissues or in C2C12 cells strongly supports a close association between Brn-3b levels and GLUT4 expression. Since Brn-3b is regulated by metabolites and insulin, this may provide a mechanism for controlling key genes that are required for normal metabolic processes in insulin-responsive tissues and its loss may contribute to abnormal glucose uptake.

Epigenetic Modification of Cloned Embryos Improves Nanog Reprogramming in Pigs.

Incomplete reprogramming of pluripotent genes in cloned embryos is associated with low cloning efficiency. Epigenetic modification agents have been shown to enhance the developmental competence of cloned embryos; however, the effect of the epigenetic modification agents on pluripotent gene reprogramming remains unclear. Here, we investigated Nanog reprogramming and the expression patterns of pluripotent transcription factors during early embryo development in pigs. We found that compared with fertilized embryos, cloned embryos displayed higher methylation in the promoter and 5'-untranslated region and lower methylation in the first exon of Nanog. When 5-aza-2'-deoxycytidine (5-aza-dC) or trichostatin A (TSA) enhanced the development of porcine cloned embryos, Nanog methylation reprogramming was also improved, similar to that detected in fertilized counterparts. Furthermore, our results showed that the epigenetic modification agents improved the expression levels of Oct4 and Sox2 and effectively promoted Nanog transcription in cloned embryos. In conclusion, our results demonstrated that the epigenetic modification agent 5-aza-dC or TSA improved Nanog methylation reprogramming and the expression patterns of pluripotent transcription factors, thereby resulting in the enhanced expression of Nanog and high development of porcine cloned embryos. This work has important implications in the improvement of cloning efficiency.

Activins A and B Regulate Fate-Determining Gene Expression in Islet Cell Lines and Islet Cells From Male Mice.

TGFß superfamily ligands, receptors, and second messengers, including activins A and B, have been identified in pancreatic islets and proposed to have important roles regulating development, proliferation, and function. We previously demonstrated that Fstl3 (an antagonist of activin activity) null mice have larger islets with ß-cell hyperplasia and improved glucose tolerance and insulin sensitivity in the absence of altered ß-cell proliferation. This suggested the hypothesis that increased activin signaling influences ß-cell expansion by destabilizing the α-cell phenotype and promoting transdifferentiation to ß-cells. We tested the first part of this hypothesis by treating α- and ß-cell lines and sorted mouse islet cells with activin and related ligands. Treatment of the αTC1-6 α cell line with activins A or B suppressed critical α-cell gene expression, including Arx, glucagon, and MafB while also enhancing ß-cell gene expression. In INS-1E ß-cells, activin A treatment induced a significant increase in Pax4 (a fate determining ß-cell gene) and insulin expression. In sorted primary islet cells, α-cell gene expression was again suppressed by activin treatment in α-cells, whereas Pax4 was enhanced in ß-cells. Activin treatment in both cell lines and primary cells resulted in phosphorylated mothers against decapentaplegic-2 phosphorylation. Finally, treatment of αTC1-6 cells with activins A or B significantly inhibited proliferation. These results support the hypothesis that activin signaling destabilized the α-cell phenotype while promoting a ß-cell fate. Moreover, these results support a model in which the ß-cell expansion observed in Fstl3 null mice may be due, at least in part, to enhanced α- to ß-cell transdifferentiation.

Neuronal Kmt2a/Mll1 histone methyltransferase is essential for prefrontal synaptic plasticity and working memory.

Neuronal histone H3-lysine 4 methylation landscapes are defined by sharp peaks at gene promoters and other cis-regulatory sequences, but molecular and cellular phenotypes after neuron-specific deletion of H3K4 methyl-regulators remain largely unexplored. We report that neuronal ablation of the H3K4-specific methyltransferase, Kmt2a/Mixed-lineage leukemia 1 (Mll1), in mouse postnatal forebrain and adult prefrontal cortex (PFC) is associated with increased anxiety and robust cognitive deficits without locomotor dysfunction. In contrast, only mild behavioral phenotypes were observed after ablation of the Mll1 ortholog Kmt2b/Mll2 in PFC. Impaired working memory after Kmt2a/Mll1 ablation in PFC neurons was associated with loss of training-induced transient waves of Arc immediate early gene expression critical for synaptic plasticity. Medial prefrontal layer V pyramidal neurons, a major output relay of the cortex, demonstrated severely impaired synaptic facilitation and temporal summation, two forms of short-term plasticity essential for working memory. Chromatin immunoprecipitation followed by deep sequencing in Mll1-deficient cortical neurons revealed downregulated expression and loss of the transcriptional mark, trimethyl-H3K4, at <50 loci, including the homeodomain transcription factor Meis2. Small RNA-mediated Meis2 knockdown in PFC was associated with working memory defects similar to those elicited by Mll1 deletion. Therefore, mature prefrontal neurons critically depend on maintenance of Mll1-regulated H3K4 methylation at a subset of genes with an essential role in cognition and emotion.

Targeting FoxM1 inhibits proliferation, invasion and migration of nasopharyngeal carcinoma through the epithelial­to-mesenchymal transition pathway.

High expression levels of the forkhead box M1 (FoxM1) transcription factor are associated with metastasis and poor prognosis of malignancies. However, little is known concerning its function in nasopharyngeal carcinoma (NPC). The present study aimed to investigate the impact of FoxM1 inhibition on the migration and invasion of NPC cells and the potential mechanisms. The effects of FoxM1 inhibitor treatment and FoxM1 silencing on the proliferation, migration and invasion of NPC CNE-1 and CNE-2 cells were examined by CCK-8, Transwell migration/invasion and colony formation assays. The effects of stable FoxM1 silencing on the growth and lung metastasis of implanted NPC were evaluated. The relative levels of FoxM1, zinc finger E-box binding homeobox 2 (ZEB2), Snail2 and E-cadherin in the different groups of NPC cells and tumors were determined by quantitative real-time PCR, western blotting and immunohistochemical assays. Treatment with thiostrepton, FoxM1 inhibitor, significantly reduced the survival of NPC cells. Treatment with thiostrepton and/or knockdown of FoxM1 inhibited the anchorage-independent proliferation, migration and invasion of NPC cells. Inhibition of FoxM1 also increased the relative levels of E-cadherin, but reduced ZEB2 and Snail2 expression in NPC cells. Stable FoxM1 silencing inhibited the growth and lung metastasis of implanted NPC in vivo, which was associated with increased levels of E-cadherin, but decreased ZEB2 and Snail2 expression in the NPC tumors. In conclusion, our data clearly indicate that knockdown of FoxM1 inhibited the growth and metastasis of human NPC by modulating epithelial-to-mesenchymal transition (EMT), and FoxM1 may be a potential target for the intervention of NPC.

Inhibition of gamma-secretase activity impedes uterine serous carcinoma growth in a human xenograft model.

OBJECTIVE: Uterine serous carcinoma (USC) represents an aggressive subtype of endometrial cancer. We sought to understand Notch pathway activity in USC and determine if pathway inhibition has anti-tumor activity. METHODS: Patient USC tissue blocks were obtained and used to correlate clinical outcomes with Notch1 expression. Three established USC cell lines were treated with gamma-secretase inhibitor (GSI) in vitro. Mice harboring cell line derived or patient derived USC xenografts (PDXs) were treated with vehicle, GSI, paclitaxel and carboplatin (P/C), or combination GSI and P/C. Levels of cleaved Notch1 protein and Hes1 mRNA were determined in GSI treated samples. Statistical analysis was performed using the Wilcoxon rank sum and Kaplan-Meier methods. RESULTS: High nuclear Notch1 protein expression was observed in 58% of USC samples with no correlation with overall survival. GSI induced dose-dependent reductions in cell number and decreased levels of cleaved Notch1 protein and Hes1 mRNA in vitro. Treatment of mice with GSI led to decreased Hes1 mRNA expression in USC xenografts. In addition, GSI impeded tumor growth of cell line xenografts as well as UT1 USC PDXs. When GSI and P/C were combined, synergistic anti-tumor activity was observed in UT1 xenografts. CONCLUSIONS: Notch1 is expressed in a large subset of USC. GSI-mediated Notch pathway inhibition led to both reduced cell numbers in vitro and decreased tumor growth of USC some xenograft models. When combined with conventional chemotherapy, GSI augmented anti-tumor activity in one USC PDX line suggesting that targeting of the Notch signaling pathway is a potential therapeutic strategy for future investigation.