TMOD-18. TARGETING THE PI3K/AKT PATHWAY IN MYCN AMPLIFIED HIGH GRADE GLIOMAS

Abstract Pediatric glioblastoma (pGBM) are incurable brain tumors with overall poor prognosis and response to treatments due to molecular and epigenetic heterogeneity. In particular, the MYCN subtype of pGBM are a highly aggressive form of GBM with a dismal median survival of only 14 months. Furthermore, this subtype is enriched with loss of the tumor suppressor genes TP53 and PTEN, leading to aberrantly active PI3K-AKT signaling pathway and DNA-checkpoint abnormalities. Here, we report the generation of a novel syngeneic mouse model that recapitulates the features of the MYCN subtype of pGBM. We isolated Sox2-Cre neural stem cells from C57BL/6 mice and transduced inverted retroviral-cassettes of the murine Mycn oncogene simultaneously with shRNA targeting tumor suppressor genes p53 and Pten. Retroviral-cassettes are flanked by tandem LoxP sites arranged so that Cre recombinase expression inverts the cassettes in frame allowing for MYCN protein expression and loss of the P53/PTEN proteins. Transgene activation is accompanied with selectable cell surface markers and fluorescent tags enabling for fluorescent activated cell sorting (FACS) of the desired cell populations. Neural stem cells with MYCN protein expression and concurrent silencing of P53 and PTEN protein (NPP cells) result in significantly increased proliferation and activation of PI3K-AKT pathway as compared to control neural stem cells and have. Injection of NPP cells into the forebrain of immune competent C57BL/6 mice result in the formation of invasive high-grade gliomas with a lethal phenotype at ~50 days post injection. Using several next generation brain penetrant small molecule inhibitors of the PI3K-AKT pathway, we show inhibition of tumorigenesis in vitro. Moreover, we have identified several novel mechanisms of PI3KAKT treatment resistance and are currently identifying therapies that may overcome this resistance through RNA seq analysis. In summary, well defined genetic drivers of GBM can lead to informed mouse model generation to test promising therapies.

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Distinct epigenetic regulation of tumor suppressor genes in putative cancer stem cells of solid tumors

International Journal of Oncology ◽

10.3892/ijo_00000807 ◽

2010 ◽

Vol 37 (6) ◽

Cited By ~ 1

Author(s):

Soejima

Keyword(s):

Stem Cells ◽

Tumor Suppressor ◽

Cancer Stem Cells ◽

Solid Tumors ◽

Epigenetic Regulation ◽

Tumor Suppressor Genes ◽

Suppressor Genes

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Abstract 4352: Using human neural stem cells to model pediatric high grade gliomas: The role of p53, c-myc, and EGFRvIII in neoplastic transformation

10.1158/1538-7445.am10-4352 ◽

2010 ◽

Author(s):

Eric H. Raabe ◽

Jarek Maciaczyk ◽

Ulf Kahlert ◽

Guido Nikkhah ◽

Charles Eberhart

Keyword(s):

Stem Cells ◽

Neural Stem Cells ◽

Neoplastic Transformation ◽

High Grade ◽

Human Neural Stem Cells ◽

High Grade Gliomas

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A new CRISPR mediated intestinal tumor mouse model targeting four canonical tumor suppressor genes.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.e16064 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. e16064-e16064

Author(s):

Hajime Kashima ◽

Daniel Veronese-Paniagua ◽

Anthony Fischer ◽

Blair Madison ◽

Deborah Rubin

Keyword(s):

Tumor Suppressor ◽

Mouse Model ◽

Tumor Suppressor Genes ◽

Rapid Development ◽

Tumor Development ◽

Intestinal Tumor ◽

Intestinal Tumors ◽

Suppressor Genes ◽

Intestinal Tumorigenesis ◽

Guide Rnas

e16064 Background: Mouse models of intestinal tumorigenesis have been developed and many of them involve mutations in the Apc gene. However, human intestinal tumors contain multiple additional sporadic mutations in tumor suppressor genes (TSGs). Our goal is to develop a novel mouse model of intestinal tumorigenesis that can recapitulate the natural history of mutations in diverse stages of tumor development. Methods: We used multiple guide RNAs to achieve random mutations in the canonical TSGs, Apc, Pten, Smad4, and Tp53. We generated transgenic (PPAS) mice that constitutively express the appropriate guide RNAs. Moreover, we achieved inducible Cas9 expression in icCas9N mice intestine using the Villin promoter to drive both a doxycycline-dependent activator and a doxycycline-inactivated repressor. We fed the doxycycline chow to PPAS:icCas9 double transgenic mice from the age of 6 to 8 weeks, and harvested intestine at 12 weeks. Results: We examined seven PPAS;icCas9 mice, and detected intestinal tumors in all the mice. Two mice had small intestinal tumor, three mice had colonic tumor, and two mice had tumors in both small and large intestine. The average number of tumors were 0.86, 1.57, 2.43 in small intestine, colon, and both respectively. We analyzed mutations in 11 tumors in 6 mice. The mutation patterns of Apc, Pten, Smad4 and Tp53 in tumors shared three distinct patterns. One was characterized by mutations in all four TSGs (n = 9). The second showed mutation in APC and Smad4 and Pten (n = 1). The third showed mutation only in Tp53 (n = 1). Normal intestine and colon in PPAS:icCas9 mice had no mutations. Conclusions: This model provides a powerful platform for modeling intestinal tumorigenesis driven by the canonical signaling pathway which are commonly dysregulated in colon cancer. This model provides a means for rapid development of intestinal tumors in mice, enabling an investigation of the relationship between novel candidate regulators of tumorigenesis and the canonical signaling pathways regulated by these four common TSGs. [Table: see text]

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Quantification of Chlorogenic Acid and Vanillin from Coffee Peel Extract and its Effect on α-Amylase Activity, Immunoregulation, Mitochondrial Oxidative Stress, and Tumor Suppressor Gene Expression Levels in H2O2-Induced Human Mesenchymal Stem Cells

Frontiers in Pharmacology ◽

10.3389/fphar.2021.760242 ◽

2021 ◽

Vol 12 ◽

Author(s):

Heba Khalil Alyahya ◽

Pandurangan Subash-Babu ◽

Ahmad Mohammad Salamatullah ◽

Khizar Hayat ◽

Nawal Albader ◽

...

Keyword(s):

Oxidative Stress ◽

Stem Cells ◽

Mesenchymal Stem Cells ◽

Tumor Suppressor ◽

Chlorogenic Acid ◽

Tumor Suppressor Genes ◽

Human Mesenchymal Stem Cells ◽

Total Polyphenol ◽

Suppressor Genes ◽

Mitochondrial Oxidative Stress

Background: Polyphenols and flavonoid-rich foods help in arresting reactive oxygen species development and protecting DNA from oxidative damage. Coffee peel (CP) preparations are consumed as beverages, and their total polyphenol or flavonoid content and their effect on oxidative stress–induced human mesenchymal stem cells (hMSCs) are poorly understood.Method: We prepared hot water extracts of CP (CPE) and quantified the amount of total polyphenol and flavonoid using HPLC analysis. In addition, CPE have been studied for their α-amylase inhibitory effect and beneficial effects in oxidative stress–induced hMSCs.Results: The obtained results show that the availability of chlorogenic acid, vanillin, and salicylic acid levels in CPE is more favorable for enhancing cell growth, nuclear integrity, and mitochondrial efficiency which is confirmed by propidium iodide staining and JC-1 staining. CPE treatment to hMSCs for 48 h reduced oxidative stress by decreasing mRNA expression levels of LPO and NOX-4 and in increasing antioxidant CYP1A, GSH, GSK-3β, and GPX mRNA expressions. Decreased pro-inflammatory (TNF-α, NF-κβ, IL-1β, TLR-4) and increased tumor suppressor genes (except Bcl-2) such as Cdkn2A, p53 expressions have been observed.Conclusions: The availability of CGA in CPs effectively reduced mitochondrial oxidative stress, reduced pro-inflammatory cytokines, and increased tumor suppressor genes.

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