scholarly journals HGG-16. DISSECTING THE EFFECT OF ATM DELETION ON RADIOSENSITIVITY IN DIFFUSE MIDLINE GLIOMAS WITH H3K27M MUTATION

2021 ◽  
Vol 23 (Supplement_1) ◽  
pp. i20-i20
Author(s):  
Maria Guerra Garcia ◽  
Katherine Deland ◽  
Lixia Luo ◽  
Yan Ma ◽  
Nerissa Williams ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mouse Models ◽  
Treatment Options ◽  
Tumor Development ◽  
Viral Gene ◽  
Loss Of Function ◽  
Primary Tumors ◽  
Primary Mouse ◽  
Therapeutic Opportunity ◽  
Viral Gene Delivery

Abstract Diffuse midline gliomas (DMGs) are responsible for a large proportion of childhood brain tumor deaths. Currently, radiation therapy is thought to be one of the most effective treatment options, but more than 90% of children still die within 2 years of diagnosis. DMGs are defined by somatic histone 3 K27M (H3K27M) mutations that have been shown to promote the G0/G1 to S cell cycle transition. The majority of DMGs also contain loss-of-function mutations in TP53. Prior research demonstrated that orthotopic xenograft and primary mouse models of non-H3K27M-mutated gliomas with inactivation of p53 are preferentially radiosensitized by inactivation of Ataxia Telangiectasia Mutated (ATM), a kinase that mediates DNA repair in response to DNA damage caused by radiation. The high frequency of mutations that deregulate p53 in DMGs raises the possibility that H3K27M-mutant DMGs may also be radiosensitized by ATM inhibition, representing a unique therapeutic opportunity. Here, we hypothesize that H3K27M-mutant DMGs that have loss of function of p53 will be radiosensitized by loss of ATM. To test this hypothesis, we used the RCAS-TVA viral gene delivery system to generate genetically-faithful primary mouse models of H3K27M-mutant DMG with p53 deletion, and we used Cre recombinase to delete Atm in the tumor cells of these mice and generated littermate controls that retained Atm. Mice were imaged weekly via luciferase-based bioluminescence to track tumor development and irradiated with three daily fractions of 10 Gy after tumor detection. We subsequently quantified the survival of mice without neurological decline following irradiation. In separate cohorts, we collected primary tumors after irradiation to verify H3K27M expression and to assess cell cycle arrest and mechanisms of cell death. These studies will elucidate mechanisms by which ATM inactivation can radiosensitize H3K27M-mutant DMGs with nonfunctioning p53, which will guide the design of clinical trials testing ATM inhibitors in DMG patients.

Opposing functions of β-arrestin 1 and 2 in Parkinson’s disease via microglia inflammation and Nprl3

2020 ◽  
Author(s):  
Yinquan Fang ◽  
Qingling Jiang ◽  
Shanshan Li ◽  
Hong Zhu ◽  
Xiao Ding ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Mouse Models ◽  
Inflammatory Responses ◽  
Microglia Activation ◽  
Loss Of Function ◽  
Neuron Loss ◽  
Primary Mouse ◽  
The Impact

Abstract Background Although β-arrestins (ARRBs) regulate diverse physiological and pathophysiological processes, their function and regulation in Parkinson’s disease (PD) remain poorly defined. Methods We measured expression of ARRB1 and ARRB2 in liposaccharide (LPS)-induced and 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced PD mice. ARRB1-deficient and ARRB2-deficient mouse were used to assess the impact of ARRBs on dopaminergic (DA) neuron loss and microglia activation in PD mouse models. After primary mouse DA neurons were exposed to the conditioned medium from ARRB1 knockdown or ARRB2 knockout microglia stimulated by LPS plus interferon γ (IFN-γ), the degeneration of DA neurons was quantified. Gain- and loss-of-function studies were used to study the effects of ARRBs on microglia activation in vitro. To further understand the mechanism, we measured the activation of classical inflammatory pathways and used RNA sequencing to identify the novel downstream effector of ARRBs. Result In this study, we demonstrate that expression of ARRB1 and ARRB2, particularly in microglia, is reciprocally regulated in PD mouse models. ARRB1 ablation ameliorates, whereas ARRB2 knockout aggravates, the pathological features of PD, including DA neuron loss, neuroinflammation and microglia activation in vivo, as well as microglia-mediated neuron damage and inflammation in vitro. In parallel, ARRB1 and ARRB2 produce adverse effects on the activation of inflammatory signal transducers and activators of transcription 1 (STAT1) and nuclear factor-κB (NF-κB) pathways in microglia. We also show that two ARRBs competitively interact with activated p65 in the NF-κB pathway and that nitrogen permease regulator-like 3 (Nprl3), a functionally poorly characterized protein, is a novel effector acting downstream of both ARRBs. Conclusion Collectively, these data demonstrate that two closely related ARRBs have completely opposite functions in microglia-mediated inflammatory responses, via Nprl3, and differentially affect the pathogenesis of PD, and suggest a potential therapeutic strategy.

scholarly journals Dysregulation of miR-23b-5p promotes cell proliferation via targeting FOXM1 in hepatocellular carcinoma

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xinchen Yang ◽  
Shikun Yang ◽  
Jinhua Song ◽  
Wenjie Yang ◽  
Yang Ji ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Tumor Development ◽  
Loss Of Function ◽  
Cycle Arrest ◽  
Cell Proliferation Inhibition

AbstractGrowing evidence demonstrates that MicroRNAs (miRNAs) play an essential role in contributing to tumor development and progression. However, the underlying role and mechanisms of miR-23b-5p in hepatocellular carcinoma (HCC) formation remain unclear. Our study showed that miR-23b-5p was downregulated in the HCC tissues and cell lines, and lower expression of miR-23b-5p was associated with more severe tumor size and poorer survival. Gain- or loss-of-function assays demonstrated that miR-23b-5p induced G0/G1 cell cycle arrest and inhibited cell proliferation both in vitro and in vivo. qRT-PCR, western blot and luciferase assays verified that Mammalian transcription factor Forkhead Box M1 (FOXM1), upregulated in HCC specimens, was negatively correlated with miR-23b-5p expression and acted as a direct downstream target of miR-23b-5p. In addition, miR-23b-5p could regulate cyclin D1 and c-MYC expression by directly targeting FOXM1. Further study revealed that restoration of FOXM1 neutralized the cell cycle arrest and cell proliferation inhibition caused by miR-23b-5p. Taken together, our findings suggest that miR-23b-5p acted as a tumor suppressor role in HCC progression by targeting FOXM1 and may serve as a potential novel biomarker for HCC diagnosis and prognosis.

Preclinical testing using tumors from genetically engineered mouse mammary models

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 10067-10067
Author(s):  
L. Varticovski ◽  
M. G. Hollingshead ◽  
M. R. Anver ◽  
A. I. Robles ◽  
J. E. Green ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Clinical Trials ◽  
Mouse Models ◽  
Metastatic Disease ◽  
Tumor Development ◽  
Genetically Engineered ◽  
Cell Suspensions ◽  
Preclinical Testing ◽  
Primary Tumors ◽  
Tumor Bearing

10067 Background: Mouse models have been used extensively in preclinical testing of anticancer drugs. However, few of these models reflect the progression of human disease, and even fewer predict the performance of these drugs in clinical trials. Testing anticancer therapies in genetically engineered mouse (GEM) holds the promise of improving preclinical models and guiding the design of clinical trials. Unfortunately, the use of tumor-bearing GEM is hampered by the difficulty in simultaneously obtaining sufficient numbers of animals with the same stage of tumor development. The additional complexity in testing breast cancer therapies in the mouse is that all 10 mammary glands can develop tumors, frequently at different times. Methods: To circumvent the variable tumor latency and lack of synchrony in GEM, we transplanted tumor fragments or cell suspensions from multiple mammary tumor-bearing GEM into the mammary fat pad or subcutaneously into naïve syngeneic, immunodeficient athymic nude, or scid mice. Results: Tumors transplanted as fragments or cell suspensions derived from anterior mammary gland grew faster than the posterior tumors for serial passages without any significant morphologic differences. Cell suspensions using fresh or frozen cells were equally effective in generating tumors, and increasing the numbers of transplanted cells resulted in faster tumor growth. The transplantation strategy was reproducible in multiple breast cancer mouse models, including MMTV-PyMT, -Her2/neu, -wnt1/p53, BRCA1/p53, and others. Metastatic disease in the lungs was evident after removing the primary tumors at different rates for each mouse model. The transplanted primary tumors and the tumors arising in the original GEM had similar morphologic appearance and sensitivity to several chemotherapeutic and novel molecular targeted agents. Conclusions: We have established transplantable synchronous mammary tumors from GEM which also develop metastatic disease. These valuable mouse models are suitable for studying tumor-host interactions, tumor progression, and preclinical testing in a well-characterized molecular and genetic background. Testing these GEM tumors for conventional and novel molecular targeted therapies will be discussed. No significant financial relationships to disclose.

scholarly journals p21 Is a Critical CDK2 Regulator Essential for Proliferation Control in Rb-deficient Cells

1998 ◽  
Vol 141 (2) ◽  
pp. 503-514 ◽  
Author(s):  
James Brugarolas ◽  
Roderick T. Bronson ◽  
Tyler Jacks
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Tumor Development ◽  
Tumor Formation ◽  
Cell Cycle Regulators ◽  
Loss Of Function ◽  
Extrinsic Factors ◽  
Cyclin Dependent Kinases ◽  
Inhibition Of Growth

Proliferation in mammalian cells is controlled primarily in the G1-phase of the cell cycle through the action of the G1 cyclin–dependent kinases, CDK4 and CDK2. To explore the mechanism of cellular response to extrinsic factors, specific loss of function mutations were generated in two negative regulators of G1 progression, p21 and pRB. Individually, these mutations were shown to have significant effects in G1 regulation, and when combined, Rb and p21 mutations caused more profound defects in G1. Moreover, cells deficient for pRB and p21 were uniquely capable of anchorage-independent growth. In contrast, combined absence of pRB and p21 function was not sufficient to overcome contact inhibition of growth nor for tumor formation in nude mice. Finally, animals with the genotype Rb+/−;p21−/− succumbed to tumors more rapidly than Rb+/− mice, suggesting that in certain contexts mutations in these two cell cycle regulators can cooperate in tumor development.

Penile squamous cell carcinoma is genomically similar to other HPV-driven tumors.

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 505-505 ◽  
Author(s):  
Jad Chahoud ◽  
Barrett Z. McCormick ◽  
Frederico Netto ◽  
Priya Rao ◽  
Curtis R. Pickering ◽  
...  
Keyword(s):  
Treatment Options ◽  
Tumor Development ◽  
Tumor Stage ◽  
Genetic Alterations ◽  
Lymph Node Status ◽  
Cancer Genes ◽  
Multiple Cancer ◽  
Primary Tumors ◽  
Md Anderson ◽  
Tumor Types

505 Background: PSCC is rare with limited treatment options for advanced disease. There have been no published genome-wide studies on the genetic alterations of PSCCs or on the differences between HPV (+) and HPV (−) PSCCs. We report the largest WES analysis of PSCC. Methods: We identified 34 pts diagnosed with PSCC, at MD Anderson, with primary tumors or metastatic lesions sufficient for WES. Patients, tumor and surgical characteristics were available through the MD Anderson prospective registry. Genomic DNAs from both Fresh frozen macrodissected tumors and paired-normal penile tissues were analyzed by WES. Results: Patients clinical characteristics are summarized in table 1. Eight of the most frequently mutated PSCC genes (NOTCH1 (35%), TP53 (35%), CDKN2A (24%), PIK3CA (21%), CASP8 (21%), FAT1 (18%), FBXW7 (15%) and EP300 (12%)) were significantly mutated in other SCC tumor types. Importantly, 8/8 and 5/8 genes were significant in head and neck SCC and cervical SCC, respectively, including 3 (CASP8, FXBW7, and EP300) genes that are only significant in these tumor types. TP53 mutations were associated with HPV (-) PSCC and were absent in HPV (+) SCC (P= 0.03). EP300 mutations were associated with advanced primary tumor stage. Of note we did not identify unique mutations associated with lymph node status. Conclusions: This is the largest systematic analyses of PSCC genomics uncovering the involvement of multiple cancer genes that are likely to be contributing to tumor development including; TP53, squamous differentiation, cell cycle, and chromatin regulation. PSCC are genomically similar to other HPV related SCC, and provide a therapeutic rationale for considering strategies successful in HPV related cancers. [Table: see text]

scholarly journals ROR2 has a protective role in melanoma by inhibiting Akt activity, cell-cycle progression, and proliferation

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
María Victoria Castro ◽  
Gastón Alexis Barbero ◽  
María Belén Villanueva ◽  
Luca Grumolato ◽  
Jérémie Nsengimana ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Growth ◽  
Cell Cycle Progression ◽  
Orphan Receptor ◽  
Cell Cycle Regulators ◽  
Loss Of Function ◽  
Proliferation Markers ◽  
Cycle Progression ◽  
Primary Tumors

Abstract Background Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a Wnt5a receptor aberrantly expressed in cancer that was shown to either suppress or promote carcinogenesis in different tumor types. Our goal was to study the role of ROR2 in melanoma. Methods Gain and loss-of-function strategies were applied to study the biological function of ROR2 in melanoma. Proliferation assays, flow cytometry, and western blotting were used to evaluate cell proliferation and changes in expression levels of cell-cycle and proliferation markers. The role of ROR2 in tumor growth was assessed in xenotransplantation experiments followed by immunohistochemistry analysis of the tumors. The role of ROR2 in melanoma patients was assessed by analysis of clinical data from the Leeds Melanoma Cohort. Results Unlike previous findings describing ROR2 as an oncogene in melanoma, we describe that ROR2 prevents tumor growth by inhibiting cell-cycle progression and the proliferation of melanoma cells. The effect of ROR2 is mediated by inhibition of Akt phosphorylation and activity which, in turn, regulates the expression, phosphorylation, and localization of major cell-cycle regulators including cyclins (A, B, D, and E), CDK1, CDK4, RB, p21, and p27. Xenotransplantation experiments demonstrated that ROR2 also reduces proliferation in vivo, resulting in inhibition of tumor growth. In agreement with these findings, a higher ROR2 level favors thin and non-ulcerated primary melanomas with reduced mitotic rate and better prognosis. Conclusion We conclude that the expression of ROR2 slows down the growth of primary tumors and contributes to prolonging melanoma survival. Our results demonstrate that ROR2 has a far more complex role than originally described.

Recent advances in the analysis full/empty capsid ratio and genome integrity of adeno-associated virus (AAV) gene delivery vectors

2020 ◽  
Vol 20 ◽  
Author(s):  
L. Hajba ◽  
A. Guttman
Keyword(s):  
Gene Delivery ◽  
High Efficiency ◽  
Analytical Techniques ◽  
Viral Gene ◽  
Adeno Associated Virus ◽  
Gene Delivery Vectors ◽  
Empty Capsid ◽  
Purification Methods ◽  
Viral Gene Delivery

: Adeno-associated virus (AAV) is one of the most promising viral gene delivery vectors with long-term gene expression and disease correction featuring high efficiency and excellent safety in human clinical trials. During the production of AAV vectors,there are several quality control (QC)parameters that should be rigorously monitored to comply with clini-cal safety and efficacy. This review gives a short summary of the most frequently used AVV production and purification methods,focusing on the analytical techniques applied to determine the full/empty capsid ratio and the integrity of the encapsidated therapeutic DNA of the products.

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