DNA demethylation reactivation of imprinted genes in cell lines from patients with Prader-Willi syndrome and a mouse model

2007 ◽  
Vol 143A (12) ◽  
pp. 1386-1390 ◽  
Author(s):  
Kyoko Takano ◽  
Maki Okajima ◽  
Shinji Saitoh
Keyword(s):  
Mouse Model ◽  
Cell Lines ◽  
Dna Demethylation ◽  
Imprinted Genes ◽  
Prader Willi Syndrome

scholarly journals Targeting the histone methyltransferase G9a activates imprinted genes and improves survival of a mouse model of Prader–Willi syndrome

2016 ◽  
Vol 23 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Yuna Kim ◽  
Hyeong-Min Lee ◽  
Yan Xiong ◽  
Noah Sciaky ◽  
Samuel W Hulbert ◽  
...  
Keyword(s):  
Mouse Model ◽  
Histone Methyltransferase ◽  
Imprinted Genes ◽  
Prader Willi Syndrome

scholarly journals Differential activation of the hprt gene on the inactive X chromosome in primary and transformed Chinese hamster cells.

1989 ◽  
Vol 9 (4) ◽  
pp. 1635-1641 ◽  
Author(s):  
S G Grant ◽  
R G Worton
Keyword(s):  
Cell Lines ◽  
X Chromosome ◽  
Gene Activation ◽  
Chinese Hamster ◽  
Fibroblast Cell ◽  
Dna Demethylation ◽  
Hprt Gene ◽  
Primary Fibroblast ◽  
Chinese Hamster Cells ◽  
Inactive X Chromosome

We have investigated the genetic activation of the hprt (hypoxanthine-guanine phosphoribosyltransferase) gene located on the inactive X chromosome in primary and transformed female diploid Chinese hamster cells after treatment with the DNA methylation inhibitor 5-azacytidine (5azaCR). Mutants deficient in HPRT were first selected by growth in 6-thioguanine from two primary fibroblast cell lines and from transformed lines derived from them. These HPRT- mutants were then treated with 5azaCR and plated in HAT (hypoxanthine-methotrexate-thymidine) medium to select for cells that had reexpressed the hprt gene on the inactive X chromosome. Contrary to previous results with primary human cells, 5azaCR was effective in activating the hprt gene in primary Chinese hamster fibroblasts at a low but reproducible frequency of 2 x 10(-6) to 7 x 10(-6). In comparison, the frequency in independently derived transformed lines varied from 1 x 10(-5) to 5 x 10(-3), consistently higher than in the nontransformed cells. This increase remained significant when the difference in growth rates between the primary and transformed lines was taken into account. Treatment with 5azaCR was also found to induce transformation in the primary cell lines but at a low frequency of 4 x 10(-7) to 8 x 10(-7), inconsistent with a two-step model of transformation followed by gene activation to explain the derepression of hprt in primary cells. Thus, these results indicate that upon transformation, the hprt gene on the inactive Chinese hamster X chromosome is rendered more susceptible to action by 5azaCR, consistent with a generalized DNA demethylation associated with the transformation event or with an increase in the instability of an underlying primary mechanism of X inactivation.

scholarly journals 736 Treatment with decitabine (DAC) induces the expression of stemness markers, PD-L1 and NY-ESO-1 in colorectal cancer

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A767-A767
Author(s):  
Nassiba Taib ◽  
Maysaloun Merhi ◽  
Varghese Inchakalody ◽  
Sarra Mestiri ◽  
Afsheen Raza ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
New York ◽  
Colon Cancer ◽  
Cancer Cells ◽  
Cell Lines ◽  
Tumor Antigen ◽  
Immune Escape ◽  
Combined Treatment ◽  
Cpg Islands ◽  
Dna Demethylation

BackgroundColorectal cancer (CRC) is a leading cause of cancer related deaths. Epigenetic silencing of numerous tumor suppressor genes by promoter region hypermethylation has been found in a variety of cancers including CRC. The chemotherapeutic drug decitabine (DAC) is a strong inducer of DNA demethylation. Primary cancer cells are known to express stemness markers as an escape pathway of treatment. Moreover, immunoregulatory genes can be inactivated in these cells by methylation of promoter CpG islands. Both mechanisms are known to play crucial roles in tumor progression. In this study, we investigated the effect of DAC on the expression of stemness markers, Programmed cell death ligand (PD-L1) and New York esophageal squamous cell carcinoma 1 (NY-ESO-1) in a metastatic (1872 Col) and a primary (1076 Col) colorectal cancer cell lines isolated from patients' tumor tissues.MethodsThe 1076 Col and 1872 Col cell lines were treated with 5 μM of DAC for 48 hours. Differential expression of a panel of stemness and immunoregulatory markers before and after treatment was analyzed by Flow cytometry (FACS), Western Blotting (WB) and quantitative real time PCR (qRT-PCR).ResultsThe following stemness markers: CD44, Nanog, KLF-4, CD133 and MSI1 were up-regulated in both 1076 Col and 1872 Col cell lines after treatment. However, significant up-regulation of the immunoinhibitory PD-L1 marker was recorded after treatment only in the metastatic 1872 Col. Interestingly, the NY-ESO-1 tumor antigen was significantly upregulated in both 1076 Col and 1872 Col cell lines after treatment.ConclusionsTreatment of colon cancer cells with DAC induces chemotherapeutic resistance as evidenced by the induction/upregulation of the stemness markers; and immune escape mechanism through the induction/upregulation of PD-L1. However, such treatment resulted in the induction/expression of the most immunogenic NY-ESO-1 tumor antigen. Our data suggest the importance use of a combined treatment strategy utilizing chemotherapy (DAC) with anti-PD-L-1/PD-1treatment in colon cancer patients.Ethics ApprovalThe study obtained ethical approval from Hamad Medical Corporation, Medical Research Center Ethic Board: Grant ID : IRGC-04-SI-17-142.

scholarly journals Cytolytic Epstein-Barr Virus Reactivation Therapy for EBV-Associated Gastric Carcinoma

2020 ◽  
pp. 1-10
Author(s):  
Jaap M. Middeldorp ◽  
Zlata Novalić ◽  
Sandra A.W.M. Verkuijlen ◽  
Astrid E. Greijer ◽  
Jaap M. Middeldorp
Keyword(s):  
Gastric Carcinoma ◽  
Mouse Model ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Drug Combinations ◽  
Model Systems ◽  
Virus Reactivation ◽  
Barr Virus ◽  
Ebv Reactivation ◽  
Epstein Barr

Background: Epstein-Barr virus associated gastric carcinoma (EBVaGC) is considered a distinct GC disease entity, with the virus persisting in a latent phase. Treatment with Epirubicin, Capecitabine and Cisplatin (ECC combination) showed survival benefit in patients with GC in clinical trials (MAGIC study and CRITICS study) when compared to chemotherapy with Capecitabine and Cisplatin (GCb/Cis). Current treatment protocols for GC do not consider virus involvement. Methods: In this study, we tested a CytoLytic Virus Activation (CLVA) strategy consisting of the ECC combination or GCb/Cis together with the HDAC inhibitor Valproic acid (VPA) to define whether EBV reactivation and subsequent antiviral treatment with Ganciclovir (GCV) could be used as virus-targeted therapy for EBVaGC. Drug combinations with VPA and GCV were evaluated in multiple cell lines and in an EBVaGC mouse model based on human naturally EBV-infected SNU-719 cells. Results: EBV reactivation was demonstrated by lytic mRNA transcripts and proteins in treated cells, and the virus-reactivating capacity of different CLVA drug combinations was compared in C666.1, AGS-BX1 and SNU-719 cell lines. In an EBVaGC mouse model, GCb/Cis with VPA and GCV strongly reduced tumor volume and showed the highest potential for EBV-reactivation. Upon a single round of CLVA treatment, EBV DNA levels in circulation decreased, and loss of EBV-positive cells in treated tumors was observed. In vivo EBV-reactivation was revealed by the presence of lytic gene transcripts and proteins in tumor tissues 6 days after treatment. Conclusion: In EBVaGC model systems, CLVA treatment showed a more potent virus reactivation and killing of tumor cells when compared to standard chemotherapy alone, suggesting that addition of VPA plus GCV to the ECC or GCb/Cis combination should be considered in future clinical studies.

scholarly journals Stochastic Loss of Silencing of the Imprinted Ndn/NDN Allele, in a Mouse Model and Humans with Prader-Willi Syndrome, Has Functional Consequences

PLoS Genetics ◽  
2013 ◽  
Vol 9 (9) ◽  
pp. e1003752 ◽  
Author(s):  
Anne Rieusset ◽  
Fabienne Schaller ◽  
Unga Unmehopa ◽  
Valery Matarazzo ◽  
Françoise Watrin ◽  
...  
Keyword(s):  
Mouse Model ◽  
Prader Willi Syndrome ◽  
Functional Consequences

scholarly journals Berberine reduces temozolomide resistance by inducing autophagy via the ERK1/2 signaling pathway in glioblastoma

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Huiling Qu ◽  
Xiaofu Song ◽  
Zhuyin Song ◽  
Xin Jiang ◽  
Xin Gao ◽  
...  
Keyword(s):  
Mouse Model ◽  
Cell Lines ◽  
Therapeutic Agent ◽  
Chemotherapeutic Agent ◽  
Experimental System ◽  
Resistant Cell ◽  
Isoquinoline Alkaloid ◽  
Therapeutic Resistance ◽  
In Vivo Efficacy

Abstract Background The ability to treat glioblastoma (GBM) using the chemotherapeutic agent temozolomide (TMZ) has been hampered by the development of therapeutic resistance. In this study, we assessed the ability of the isoquinoline alkaloid berberine to alter GBM TMZ resistance using two different TMZ-resistant cell lines to mimic a physiologically relevant GBM experimental system. Methods By treating these resistant cell lines with berberine followed by TMZ, we were able to assess the chemosensitivity of these cells and their parental strains, based on their performance in the MTT and colony formation assays, as well as on the degree of detectable apoptosis that was detected in the strains. Furthermore, we used Western blotting to assess autophagic responses in these cell lines, and we extended this work into a xenograft mouse model to assess the in vivo efficacy of berberine. Results Through these experiments, our findings indicated that berberine enhanced autophagy and apoptosis in TMZ-resistant cells upon TMZ treatment in a manner that was linked with ERK1/2 signaling. Similarly, when used in vivo, berberine increased GBM sensitivity to TMZ through ERK1/2 signaling pathways. Conclusions These findings demonstrate that berberine is an effective method of increasing the sensitization of GBM cells to TMZ treatment in a manner that is dependent upon the ERK1/2-mediated induction of autophagy, thus making berberine a potentially viable therapeutic agent for GBM treatment.

Development and characterization of immortalized fibroblastoid cell lines from an FA(C) mouse model

1998 ◽  
Vol 408 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Darrell J Tomkins ◽  
Melanie Care ◽  
Madeleine Carreau ◽  
Manuel Buchwald
Keyword(s):  
Mouse Model ◽  
Cell Lines
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