TMOD-02. GENERATION OF A NOVEL MOUSE MODEL FOR BRAIN TUMORS OF THE DNA METHYLATION CLASS “GBM MYCN”

Abstract DNA methylation based classification of brain tumors has revealed a high heterogeneity between tumors and led to the description of multiple distinct subclasses. The increasing subdivision of tumors can help to understand molecular mechanisms of tumor development and to improve therapy if appropriate model systems for preclinical research are available. Multiple recent publications have described a subgroup of pediatric glioblastoma which is clearly separable from other pediatric and adult glioblastoma in its DNA methylation profile (GBM MYCN). Many cases in this group are driven by MYCN amplifications and harbor TP53 mutations. These tumors almost exclusively occur in children and were further described as highly aggressive with a median overall survival of only 14 months. In order to further investigate the biology and treatment options of these tumors, we generated hGFAP-cre::TP53 Fl/Fl ::lsl-MYCN mice. These mice carry a loss of TP53 and show aberrant MYCN expression in neural precursors of the central nervous system. The animals develop large forebrain tumors within the first 80 days of life with 100 % penetrance. These tumors resemble human GBM MYCN tumors histologically and are sensitive to AURKA and ATR inhibitors in vitro. We believe that further characterization of the model and in vivo treatment studies will pave the way to improve treatment of patients with these highly aggressive tumors.

Download Full-text

Protein Kinase C Signaling Mediates a Program of Cell Cycle Withdrawal in the Intestinal Epithelium

The Journal of Cell Biology ◽

10.1083/jcb.151.4.763 ◽

2000 ◽

Vol 151 (4) ◽

pp. 763-778 ◽

Cited By ~ 81

Author(s):

Mark R. Frey ◽

Jennifer A. Clark ◽

Olga Leontieva ◽

Joshua M. Uronis ◽

Adrian R. Black ◽

...

Keyword(s):

Cell Cycle ◽

Protein Kinase C ◽

Protein Kinase ◽

Intestinal Epithelium ◽

Molecular Mechanisms ◽

Model Systems ◽

Intestinal Epithelial ◽

Kinase C

Members of the protein kinase C (PKC) family of signal transduction molecules have been widely implicated in regulation of cell growth and differentiation, although the underlying molecular mechanisms involved remain poorly defined. Using combined in vitro and in vivo intestinal epithelial model systems, we demonstrate that PKC signaling can trigger a coordinated program of molecular events leading to cell cycle withdrawal into G0. PKC activation in the IEC-18 intestinal crypt cell line resulted in rapid downregulation of D-type cyclins and differential induction of p21waf1/cip1 and p27kip1, thus targeting all of the major G1/S cyclin-dependent kinase complexes. These events were associated with coordinated alterations in expression and phosphorylation of the pocket proteins p107, pRb, and p130 that drive cells to exit the cell cycle into G0 as indicated by concomitant downregulation of the DNA licensing factor cdc6. Manipulation of PKC isozyme levels in IEC-18 cells demonstrated that PKCα alone can trigger hallmark events of cell cycle withdrawal in intestinal epithelial cells. Notably, analysis of the developmental control of cell cycle regulatory molecules along the crypt–villus axis revealed that PKCα activation is appropriately positioned within intestinal crypts to trigger this program of cell cycle exit–specific events in situ. Together, these data point to PKCα as a key regulator of cell cycle withdrawal in the intestinal epithelium.

Download Full-text

Linc00426 accelerates lung adenocarcinoma progression by regulating miR-455-5p as a molecular sponge

Cell Death and Disease ◽

10.1038/s41419-020-03259-2 ◽

2020 ◽

Vol 11 (12) ◽

Author(s):

Hongli Li ◽

Qingjie Mu ◽

Guoxin Zhang ◽

Zhixin Shen ◽

Yuanyuan Zhang ◽

...

Keyword(s):

Lung Adenocarcinoma ◽

Molecular Mechanisms ◽

Epithelial Mesenchymal Transition ◽

Ectopic Expression ◽

Tumor Development ◽

Biological Significance ◽

Mesenchymal Transition

AbstractIncreasing lines of evidence indicate the role of long non-coding RNAs (LncRNAs) in gene regulation and tumor development. Hence, it is important to elucidate the mechanisms of LncRNAs underlying the proliferation, metastasis, and invasion of lung adenocarcinoma (LUAD). We employed microarrays to screen LncRNAs in LUAD tissues with and without lymph node metastasis and revealed their effects on LUAD. Among them, Linc00426 was selected for further exploration in its expression, the biological significance, and the underlying molecular mechanisms. Linc00426 exhibits ectopic expression in LUAD tissues and cells. The ectopic expression has been clinically linked to tumor size, lymphatic metastasis, and tumor differentiation of patients with LUAD. The deregulation of Linc00426 contributes to a notable impairment in proliferation, invasion, metastasis, and epithelial–mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, the deregulation of Linc00426 could reduce cytoskeleton rearrangement and matrix metalloproteinase expression. Meanwhile, decreasing the level of Linc00426 or increasing miR-455-5p could down-regulate the level of UBE2V1. Thus, Linc00426 may act as a competing endogenous RNA (ceRNA) to abate miR-455-5p-dependent UBE2V1 reduction. We conclude that Linc00426 accelerates LUAD progression by acting as a molecular sponge to regulate miR-455-5p, and may be a potential novel tumor marker for LUAD.

Download Full-text

Comprehensive genomic profiling of glioblastoma tumors, BTICs, and xenografts reveals stability and adaptation to growth environments

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1813495116 ◽

2019 ◽

Vol 116 (38) ◽

pp. 19098-19108 ◽

Cited By ~ 11

Author(s):

Yaoqing Shen ◽

Cameron J. Grisdale ◽

Sumaiya A. Islam ◽

Pinaki Bose ◽

Jake Lever ◽

...

Keyword(s):

Brain Tumor ◽

Massively Parallel Sequencing ◽

Treatment Options ◽

Culture Conditions ◽

Model Systems ◽

Sample Type ◽

Tumor Initiating Cells ◽

Growth Environment

Glioblastoma multiforme (GBM) is the most deadly brain tumor, and currently lacks effective treatment options. Brain tumor-initiating cells (BTICs) and orthotopic xenografts are widely used in investigating GBM biology and new therapies for this aggressive disease. However, the genomic characteristics and molecular resemblance of these models to GBM tumors remain undetermined. We used massively parallel sequencing technology to decode the genomes and transcriptomes of BTICs and xenografts and their matched tumors in order to delineate the potential impacts of the distinct growth environments. Using data generated from whole-genome sequencing of 201 samples and RNA sequencing of 118 samples, we show that BTICs and xenografts resemble their parental tumor at the genomic level but differ at the mRNA expression and epigenomic levels, likely due to the different growth environment for each sample type. These findings suggest that a comprehensive genomic understanding of in vitro and in vivo GBM model systems is crucial for interpreting data from drug screens, and can help control for biases introduced by cell-culture conditions and the microenvironment in mouse models. We also found that lack of MGMT expression in pretreated GBM is linked to hypermutation, which in turn contributes to increased genomic heterogeneity and requires new strategies for GBM treatment.

Download Full-text

Nutraceuticals for the Treatment of Diabetic Retinopathy

Nutrients ◽

10.3390/nu11040771 ◽

2019 ◽

Vol 11 (4) ◽

pp. 771 ◽

Cited By ~ 20

Author(s):

Maria Grazia Rossino ◽

Giovanni Casini

Keyword(s):

Diabetic Retinopathy ◽

Molecular Mechanisms ◽

Treatment Options ◽

Vitreoretinal Surgery ◽

In Vivo Studies ◽

Early Diabetes ◽

Advanced Stages ◽

Endothelial Growth Factor

Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus and is characterized by degeneration of retinal neurons and neoangiogenesis, causing a severe threat to vision. Nowadays, the principal treatment options for DR are laser photocoagulation, vitreoretinal surgery, or intravitreal injection of drugs targeting vascular endothelial growth factor. However, these treatments only act at advanced stages of DR, have short term efficacy, and cause side effects. Treatment with nutraceuticals (foods providing medical or health benefits) at early stages of DR may represent a reasonable alternative to act upstream of the disease, preventing its progression. In particular, in vitro and in vivo studies have revealed that a variety of nutraceuticals have significant antioxidant and anti-inflammatory properties that may inhibit the early diabetes-driven molecular mechanisms that induce DR, reducing both the neural and vascular damage typical of DR. Although most studies are limited to animal models and there is the problem of low bioavailability for many nutraceuticals, the use of these compounds may represent a natural alternative method to standard DR treatments.

Download Full-text

Novel insights into the regulation of chemerin expression: role of acute-phase cytokines and DNA methylation

10.1101/765834 ◽

2019 ◽

Author(s):

Kamila Kwiecien ◽

Piotr Brzoza ◽

Pawel Majewski ◽

Izabella Skulimowska ◽

Kamil Bednarczyk ◽

...

Keyword(s):

Dna Methylation ◽

Acute Phase ◽

Molecular Mechanisms ◽

Retinoic Acid Receptor ◽

Constitutive Expression ◽

Sequencing Analysis ◽

Mrna Levels ◽

Pleiotropic Actions

AbstractChemerin is a chemoattractant protein with adipokine properties encoded by the retinoic acid receptor responder 2 (RARRES2) gene. It has gained more attention over the past few years due to its multilevel impact on metabolism and immune responses. The pleiotropic actions of chemerin include chemotaxis of dendritic cells, macrophages and natural killers (NK) subsets, bactericidal activity as well as regulation of adipogenesis and glucose metabolism. Therefore, reflecting the pleiotropic actions of chemerin, expression of RARRES2 is regulated by a variety of inflammatory and metabolic mediators. However, for most cell types, the molecular mechanisms controlling constitutive and regulated chemerin expression are poorly characterized. Here we show that RARRES2 mRNA levels in murine adipocytes are upregulated in vitro and in vivo by acute-phase cytokines, IL-1β and OSM. In contrast to adipocytes, these cytokines exerted a weak, if any, response in mouse hepatocytes, suggesting that the effect of IL-1β and OSM on chemerin expression is specific to fat tissue. Moreover, we show that DNA methylation controls the constitutive expression of chemerin. Bisulfite sequencing analysis showed low methylation levels within −735 to +258 bp of the murine RARRES2 gene promoter in unstimulated adipocytes and hepatocytes. In contrast to these cells, the RARRES2 promoter is highly methylated in B lymphocytes, cells that do not produce chemerin. Together, our findings reveal previously uncharacterized mediators and mechanisms controlling chemerin expression in various cells.

Download Full-text

GABRQ is Overexpressed and Correlated with Tumor Progression in Breast Cancer

10.21203/rs.3.rs-503791/v1 ◽

2021 ◽

Author(s):

Ran Mei ◽

Xichun Cui ◽

Lili Zheng ◽

Li Jingyi

Keyword(s):

Breast Cancer ◽

Molecular Mechanisms ◽

Tumor Development ◽

Bioinformatic Analysis ◽

Gamma Aminobutyric Acid ◽

Nude Mouse Model ◽

Expression Levels ◽

The Public

Abstract Background: Breast cancer (BRCA) is the most common type of women's cancer with a high incidence. The function of gamma-aminobutyric acid A receptor θ subunit (GABRQ) has been studied in other cancers. The results demonstrated that the expression levels of GABRQ were closely associated with tumor prognosis. However, the functions and mechanisms of GABRQ in BRCA remain unclear.Materials and methods: We used the public genome datasets and a tissue microarray (TMA) cohort to analyze the GABRQ expression levels. We performed Immunohistochemistry (IHC) and Western blot to determine GABRQ expression in BRCA cell lines and tissues. Cell proliferation was assessed by EDU assay and colony formation assay. Transwell assay was carried out to investigate the cell invasion ability in vitro and Xenograft nude mouse model was constructed to test the function of GABRQ on tumor growth in vivo. Moreover, we utilized bioinformatic analysis to identify the potential molecular mechanisms mediated by GABRQ modification in BRCA.Results: GABRQ was markedly up-regulated in BRCA tissues, and the expression levels of GABRQ were closely associated with BRCA prognosis. Functional analysis elucidated that knockdown of GABRQ could suppress BRCA cell growth and invasion in vitro, and inhibit tumor development in vivo. Moreover, we found that GABRQ overexpression activated the EMT signaling pathway.Conclusions: These results demonstrated that the function of GABRQ in BRCA progression provided potential prognostic predictors for BRCA patients.

Download Full-text

In Vitro and In Vivo Models to Study Nephropathic Cystinosis

Cells ◽

10.3390/cells11010006 ◽

2021 ◽

Vol 11 (1) ◽

pp. 6

Author(s):

Pang Yuk Cheung ◽

Patrick T. Harrison ◽

Alan J. Davidson ◽

Jennifer A. Hollywood

Keyword(s):

Cell Lines ◽

Molecular Mechanisms ◽

Primary Cultures ◽

Model Systems ◽

In Vivo Model ◽

Nephropathic Cystinosis ◽

In Vivo Models ◽

Induced Pluripotent

The development over the past 50 years of a variety of cell lines and animal models has provided valuable tools to understand the pathophysiology of nephropathic cystinosis. Primary cultures from patient biopsies have been instrumental in determining the primary cause of cystine accumulation in the lysosomes. Immortalised cell lines have been established using different gene constructs and have revealed a wealth of knowledge concerning the molecular mechanisms that underlie cystinosis. More recently, the generation of induced pluripotent stem cells, kidney organoids and tubuloids have helped bridge the gap between in vitro and in vivo model systems. The development of genetically modified mice and rats have made it possible to explore the cystinotic phenotype in an in vivo setting. All of these models have helped shape our understanding of cystinosis and have led to the conclusion that cystine accumulation is not the only pathology that needs targeting in this multisystemic disease. This review provides an overview of the in vitro and in vivo models available to study cystinosis, how well they recapitulate the disease phenotype, and their limitations.

Download Full-text

Investigating the Biological and Molecular Mechanisms Underpinning the Engraftment/Selection Advantage Conferred to Hematopoietic Stem Cells by HOXB4.

Blood ◽

10.1182/blood.v104.11.2101.2101 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2101-2101

Author(s):

Michael D. Milsom ◽

Laura Hollins ◽

Dorothy Gagen ◽

Lorna B. Woolford ◽

Leslie J. Fairbairn

Keyword(s):

Molecular Mechanisms ◽

Current Knowledge ◽

Cellular Transformation ◽

Model Systems ◽

Self Renewal ◽

Hematopoietic Stem ◽

Increased Risk ◽

Vitro Analysis

Abstract We have recently demonstrated that co-expression of HOXB4 enables the enhanced delivery of HSC harbouring a second therapeutic trans-gene. Nonetheless, it is of great importance to elaborate the current knowledge about the mechanism of HOXB4 action in order to both evaluate the safety implications of its use in a clinical strategy, and to gain greater insight into the regulation of HSC self-renewal/expansion. To these ends we have performed an extensive in vitro analysis of the consequences of HOXB4 overexpression in primary murine BMC and in a murine multipotent myeloid progenitor cell line (FDCP-mix). We demonstrate for the first time in murine cells, that ectopic HOXB4 reduces the responsiveness of murine hematopoietic cells to differentiation stimuli. Furthermore, by performing a detailed investigation into the kinetics of FDCP-mix differentiation, we reveal that HOXB4 overexpression results in a specific differentiation delay as opposed to an outright block. We propose that an analogous delay is in operation in repopulating cells in order that the shift to increased assymetrical self-renewal, a requirement for stem cell expansion, is achieved. Notwithstanding this, it is clear that any perturbation in differentiation constitutes an increased risk of cellular transformation if this technology were transferred to a clinical setting. In order to further define the repercussions of ectopic HOXB4 delivery, we have developed a retroviral vector which encodes an activatable version of HOXB4. We have shown that this vector is able to mediate an in vitro differentiation delay in primary murine BMC and FDCP-mix as well as enable enhanced engraftment of BMC in vivo, both dependent upon the addition of the estrogen analogue; tamoxifen. Using this system, we are currently examining the effect of ectopic HOXB4 on the transcriptome of FDCP-mix cells, in addition to performing an in depth study into the biological mechanisms affected by HOXB4 overexpression in BMC in vivo. We envisage that these model systems will be particularly amenable to the manipulation required for target gene identification/validation.

Download Full-text

Persistent organic pollutants and obesity: are they potential mechanisms for breast cancer promotion?

Endocrine Related Cancer ◽

10.1530/erc-14-0411 ◽

2015 ◽

Vol 22 (2) ◽

pp. R69-R86 ◽

Cited By ~ 28

Author(s):

Denise K Reaves ◽

Erika Ginsburg ◽

John J Bang ◽

Jodie M Fleming

Keyword(s):

Breast Cancer ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Molecular Mechanisms ◽

Cell Function ◽

Causal Link ◽

Model Systems ◽

Tissue Microenvironment

Dietary ingestion of persistent organic pollutants (POPs) is correlated with the development of obesity. Obesity alters metabolism, induces an inflammatory tissue microenvironment, and is also linked to diabetes and breast cancer risk/promotion of the disease. However, no direct evidence exists with regard to the correlation among all three of these factors (POPs, obesity, and breast cancer). Herein, we present results from current correlative studies indicating a causal link between POP exposure through diet and their bioaccumulation in adipose tissue that promotes the development of obesity and ultimately influences breast cancer development and/or progression. Furthermore, as endocrine disruptors, POPs could interfere with hormonally responsive tissue functions causing dysregulation of hormone signaling and cell function. This review highlights the critical need for advancedin vitroandin vivomodel systems to elucidate the complex relationship among obesity, POPs, and breast cancer, and, more importantly, to delineate their multifaceted molecular, cellular, and biochemical mechanisms. Comprehensivein vitroandin vivostudies directly testing the observed correlations as well as detailing their molecular mechanisms are vital to cancer research and, ultimately, public health.

Download Full-text

Huntington's disease: from gene to potential therapy

Dialogues in Clinical Neuroscience ◽

10.31887/dcns.2001.3.1/hlehrach ◽

2001 ◽

Vol 3 (1) ◽

pp. 17-23

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Western Europe ◽

Molecular Mechanisms ◽

Late Onset ◽

Cell Metabolism ◽

Normal Function ◽

Model Systems

Huntington's disease (HD) is a progressive, late-onset neurodegenerative illness with autosomal dominant inheritance that affects one in 10 000 individuals in Western Europe. The disease is caused by a polyglutamine repeat expansion located in the N-terminal region of the huntingtin protein. The mutation is likely to act by a gain of function, but the molecular mechanisms by which it leads to neuronal dysfunction and cell death are not yet known. The normal function of huntingtin in cell metabolism is also unclear. There is no therapy for HD. Research on HD should help elucidate the pathogenetic mechanism of this illness in order to develop successful treatments to prevent or slow down symptoms. This article presents new results in HD research focusing on in vivo and in vitro model systems, potential molecular mechanisms of HD, and the development of therapeutic strategies.

Download Full-text