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Pant V, Aryal NK, Xiong S, Chau GP, Fowlkes NW, Lozano G. Alterations of the MDM2 C-terminus differentially impact its function in vivo. Cancer Res 2022; 82:1313-1320. [PMID: 35078816 PMCID: PMC8983537 DOI: 10.1158/0008-5472.can-21-2381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 12/07/2021] [Accepted: 01/20/2022] [Indexed: 01/10/2023]
Abstract
Murine double minute 2 (Mdm2) is the principal E3-ubiquitin ligase for p53 and contains a C2H2C4 type RING domain wherein the last cysteine residue is followed by an evolutionarily conserved 13 amino acid C-terminal tail. Previous studies have indicated that integrity of the C-terminal tail is critical for Mdm2 function. Recently, a mutation extending the MDM2 length by five amino acids was identified and associated with enhanced p53 response in fibroblasts and premature aging in a human patient. To investigate the importance of the conserved Mdm2 C-terminal length on p53 regulatory function in vivo, we engineered three novel mouse alleles using CRISPR-Cas9 technology. Genetic studies with these murine models showed that curtailing Mdm2 C-terminal length by even a single amino acid leads to p53-dependent embryonic lethality. Extension of the Mdm2 C-terminal length by five amino acids (QLTCL) yielded viable mice that are smaller in size, exhibit fertility problems, and have a shortened life span. Analysis of early passage mouse embryonic fibroblasts indicated impaired Mdm2 function correlates with enhanced p53 activity under stress conditions. Furthermore, analysis in mice showed tissue-specific alterations in p53 target gene expression and enhanced radiosensitivity. These results confirm the physiological importance of the evolutionarily conserved Mdm2 C-terminus in regulating p53 functions. SIGNIFICANCE This in vivo study highlights that alterations to the C-terminus of Mdm2 perturb its regulation of the tumor suppressor p53.
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Affiliation(s)
- Vinod Pant
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Neeraj K. Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Current address: Oncology R&D, AstraZeneca, 35 Gatehouse Park, Waltham, MA 02451
| | - Shunbin Xiong
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Gilda P Chau
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Natalie W. Fowlkes
- Department of Veterinary Medicine & Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Corresponding author: Guillermina Lozano, PhD, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, Tel. 713 834 6386,
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Wasylishen AR, Sun C, Moyer SM, Qi Y, Chau GP, Aryal NK, McAllister F, Kim MP, Barton MC, Estrella JS, Su X, Lozano G. Daxx maintains endogenous retroviral silencing and restricts cellular plasticity in vivo. Sci Adv 2020; 6:eaba8415. [PMID: 32821827 PMCID: PMC7406367 DOI: 10.1126/sciadv.aba8415] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/18/2020] [Indexed: 05/26/2023]
Abstract
Tumor sequencing studies have emphasized the role of epigenetics and altered chromatin homeostasis in cancer. Mutations in DAXX, which encodes a chaperone for the histone 3.3 variant, occur in 25% of pancreatic neuroendocrine tumors (PanNETs). To advance our understanding of physiological functions of Daxx, we developed a conditional Daxx allele in mice. We demonstrate that Daxx loss is well tolerated in the pancreas but creates a permissive transcriptional state that cooperates with environmental stress (inflammation) and other genetic lesions (Men1 loss) to alter gene expression and cell state, impairing pancreas recovery from inflammatory stress in vivo. The transcriptional changes are associated with dysregulation of endogenous retroviral elements (ERVs), and dysregulation of endogenous genes near ERVs is also observed in human PanNETs with DAXX mutations. Our results reveal a physiologic function of DAXX, provide a mechanism associated with impaired tissue regeneration and tumorigenesis, and expand our understanding of ERV regulation in somatic cells.
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Affiliation(s)
- Amanda R. Wasylishen
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chang Sun
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Genetics and Epigenetics Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Sydney M. Moyer
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Genetics and Epigenetics Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Yuan Qi
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Gilda P. Chau
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Neeraj K. Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Genetics and Epigenetics Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Florencia McAllister
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Michael P. Kim
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Michelle C. Barton
- Genetics and Epigenetics Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jeannelyn S. Estrella
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaoping Su
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Genetics and Epigenetics Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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Abstract
Prior to generating a new mouse model, it is important to plan the method that will be used to detect which of the mice generated have the mutation(s) desired. Nearly, all types of mutations may be detected using PCR. However, the choice of primers will differ depending upon the method used to generate the model. Transgenic mice should be genotyped across a unique junction fragment. Targeted ES cells used to generate knock-out or knock-in mice should be genotyped using primers from a unique marker in the construct and a region outside of the construct. Targeting in ES cells can also be detected using a genomic Southern blot. Mice targeted using CRISPR/Cas9 should have the region of interest amplified using PCR, and then be assessed for size changes (for large changes in sequence) by Surveyor Assay (for gene knock-out and point mutations) and/or sequenced to verify the mutation. Each of these models has a unique requirement for genotyping, and failure to understand the requirements can easily lead to loss of the gene in subsequent generations.
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Affiliation(s)
- Neeraj K Aryal
- Genes and Development Program, Department of Genetics, Graduate School for Biomedical Sciences, MD Anderson Cancer Center, Houston, TX, USA. .,Bioscience, Oncology R&D, AstraZeneca, Boston, MA, USA.
| | - Jan Parker-Thornburg
- Department of Genetics, Genetically Engineered Mouse Facility, MD Anderson Cancer Center, Houston, TX, USA.
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Aryal NK, Pant V, Wasylishen AR, Rimel BJ, Baseler L, El-Naggar AK, Mutch DG, Goodfellow PJ, Arur S, Lozano G. Dicer1 Phosphomimetic Promotes Tumor Progression and Dissemination. Cancer Res 2019; 79:2662-2668. [PMID: 30914430 DOI: 10.1158/0008-5472.can-18-2460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/23/2018] [Accepted: 03/22/2019] [Indexed: 11/16/2022]
Abstract
Dicer1 functions as a tumor suppressor in mouse models. In humans, somatic mutations are associated with many cancers in adults, and patients with DICER1 syndrome with DICER1 germline mutations are susceptible to childhood cancers. Dicer is phosphorylated by the ERK-MAP kinase pathway and because this pathway is activated in human cancers, we asked whether phosphorylated Dicer1 contributed to tumor development. In human endometrioid cancers, we discovered that phosphorylated DICER1 is significantly associated with invasive disease. To test a direct involvement of Dicer1 phosphorylation in tumor development, we studied mice with phosphomimetic alterations at the two conserved serines phosphorylated by ERK and discovered that a phosphomimetic Dicer1 drives tumor development and dissemination in two independent murine cancer models (KRas+/LA1 and p53+/- ). Our findings demonstrate that phosphomimetic Dicer1 promotes tumor development and invasion. SIGNIFICANCE: This work highlights the relevance of Dicer1 phosphorylation in mammalian tumor development and dissemination.
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Affiliation(s)
- Neeraj K Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas.,Genes and Development Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| | - Vinod Pant
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Amanda R Wasylishen
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Bobbie J Rimel
- Division of Gynecologic Oncology, Cedars Sinai Medical Center, Los Angeles, California
| | - Laura Baseler
- Department of Veterinary Medicine and Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Adel K El-Naggar
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - David G Mutch
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Washington University School of Medicine and Siteman Cancer Center, St. Louis, Missouri
| | - Paul J Goodfellow
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, The Ohio State University and James Comprehensive Cancer Center, Columbus, Ohio
| | - Swathi Arur
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas. .,Genes and Development Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas. .,Genes and Development Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
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Aryal NK, Wasylishen AR, Lozano G. CRISPR/Cas9 can mediate high-efficiency off-target mutations in mice in vivo. Cell Death Dis 2018; 9:1099. [PMID: 30368519 PMCID: PMC6204134 DOI: 10.1038/s41419-018-1146-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 09/18/2018] [Accepted: 10/11/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Neeraj K Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, USA
- Genes and Development Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | - Amanda R Wasylishen
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, USA
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, USA.
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Aryal NK, Arur S, Lozano G. Abstract A19: Phosphorylation results in nuclear translocation of Dicer protein that increases metabolism, accelerates aging, and alters tumorigenesis. Cancer Res 2018. [DOI: 10.1158/1538-7445.mousemodels17-a19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Dicer is a well-conserved and essential gene that is required for the production of micro RNAs that play key roles during development and cancer. Several studies have associated aberrant Dicer expression in humans with developmental defects (Dicer1 syndrome) and poor prognosis in various cancers. One important mechanism of controlling protein stability and function is through post-translational modification. Recently, Extracellular signal-Regulated Kinase (ERK) dependent phosphorylation of Dicer during oogenesis has been shown to be essential in C. elegans. The phosphorylation sites in Dicer (Ser1718 and Ser1842 in mice) are well conserved and the phosphorylation is necessary and sufficient for Dicer's translocalization from cytoplasm to nucleus. We are interested in understanding the phosphorylation-mediated control of Dicer function during development and cancer. To understand the role of phospho-Dicer in mammals, we have generated five new Dicer1 alleles including phospho-mimetic mouse models with both serines replaced with aspartic acids (DicerS2D), only Ser1842 replaced with aspartic acid (DicerS1842D), and only Ser1718 replaced with aspartic acid (DicerS1718D).
Phenotypic study shows that >75% of DicerS2D/S2D mutants and >60% of DicerS1842D/S1842D mutants die within five days after birth, while all heterozygous mutants and DicerS1718D/S1718D mice are phenotypically normal. The DicerS2D/S2D and DicerS1842D/S1842D survivors show signs of accelerated aging including smaller size, hunching of backbone, compromised weight gain, infertility, systemic tissue atrophy, and early lethality. We have also observed that DicerS2D/S2D animals and MEFs have increased metabolism as compared with wild type. Since aging and cancer are closely linked and altered metabolism is a hallmark of cancer, we hypothesize that phosphorylated Dicer produces an altered miRNA profile that affects metabolism, leading to developmental defects and tumorigenesis. Transcriptional profiling of MEFs and testes have shown that miRNA profiles are very different in mutants than in wild type, and the most affected pathways are metabolism and cancer. To test the role of phospho-Dicer in tumorigenesis, we crossed the DicerS2D allele into KRasLA1/+ driven nonmetastatic tumor model. The results show that phospho-Dicer reduces tumor-free survival, changes tumor spectrum, and drives metastasis in this tumor model.
Citation Format: Neeraj K. Aryal, Swathi Arur, Guillermina Lozano. Phosphorylation results in nuclear translocation of Dicer protein that increases metabolism, accelerates aging, and alters tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A19.
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Aryal NK, Wasylishen AR, Pant V, Riley-Croce M, Lozano G. Loss of digestive organ expansion factor ( Diexf) reveals an essential role during murine embryonic development that is independent of p53. Oncotarget 2017; 8:103996-104006. [PMID: 29262616 PMCID: PMC5732782 DOI: 10.18632/oncotarget.22087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/10/2017] [Indexed: 01/01/2023] Open
Abstract
Increased levels of inhibitors of the p53 tumor suppressor such as Mdm2 and Mdm4 drive tumor development and thus serve as targets for therapeutic intervention. Recently, digestive organ expansion factor (Diexf) has been identified as a novel inhibitor of p53 in zebrafish. Here, we address the potential role of Diexf as a regulator of the p53 pathway in mammals by generating Diexf knockout mice. We demonstrate that, similar to Mdm2 and Mdm4, homozygous deletion of Diexf is embryonic lethal. However, unlike in Mdm2 and Mdm4 mice, loss of p53 does not rescue this phenotype. Moreover, Diexf heterozygous animals are not sensitive to sub-lethal ionizing radiation. Thus, we conclude that Diexf is an essential developmental gene in the mouse, but is not a significant regulator of the p53 pathway during development or in response to ionizing radiation.
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Affiliation(s)
- Neeraj K Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.,Genes and Development Program, The University of Texas MD Anderson Cancer Center, UT Health Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Amanda R Wasylishen
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Vinod Pant
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Maurisa Riley-Croce
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Xiong S, Pant V, Zhang Y, Aryal NK, You MJ, Kusewitt D, Lozano G. The p53 inhibitor Mdm4 cooperates with multiple genetic lesions in tumourigenesis. J Pathol 2017; 241:501-510. [PMID: 27925213 DOI: 10.1002/path.4854] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/19/2016] [Accepted: 11/14/2016] [Indexed: 12/12/2022]
Abstract
The p53 inhibitor Mdm4 is present at high levels in multiple human cancers. Overexpression of Mdm4 in mice drives the spontaneous development of mostly lymphomas and sarcomas. In this study, we explored the ability of Mdm4 to cooperate with lesions in tumour development. The Mdm4 transgene contributed to mammary tumour development in a BALB/cJ background. High levels of Mdm4 enhanced tumour development in a mutant p53R172H heterozygous background, and reduced the need to lose the wild-type p53 allele, as compared with mice heterozygous only for the p53R172H mutation. Additionally, high levels of Mdm4 cooperated with an oncogenic K-ras mutation to drive lung tumourigenesis in vivo. Finally, we examined p53-independent functions of Mdm4 by studying the contribution of Mdm4 to tumour development in the absence of p53. Whereas the overall survival times of p53-null mice with and without the Mdm4 transgene were similar, male mice with both alterations showed significantly shorter survival than p53-null male mice, and showed differences in tumour spectrum, demonstrating a p53-independent function of Mdm4 in tumourigenesis. Furthermore, p53-null mice with the highest level of Mdm4 tended to have multiple tumours. Thus, a detailed analysis of Mdm4 transgenic mice in various genetic backgrounds shows synergy in tumour development in vivo. Mdm4 may thus serve as a therapeutic target in cancers. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Shunbin Xiong
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Vinod Pant
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yun Zhang
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Neeraj K Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - M James You
- Department of Hematopathology, The University of Texas MD. Anderson Cancer Center, Houston, TX, USA
| | - Donna Kusewitt
- Department of Carcinogenesis, Science Park Research Division, MD Anderson Cancer Center, University of Texas, Smithville, TX, USA
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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