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1.
Biochem Biophys Res Commun ; 720: 150098, 2024 Aug 06.
Article in English | MEDLINE | ID: mdl-38749190

ABSTRACT

Telomerase reverse transcriptase (TERT) not only upholds telomeric equilibrium but also plays a pivotal role in multiple non-canonical cellular mechanisms, particularly in the context of aging, cancer, and genomic stability. Though depletion of SIRT1 in mouse embryonic fibroblasts has demonstrated telomere shortening, the impact of SIRT1 on enabling TERT to regulate telomeric homeostasis remains enigmatic. Here, we reveal that SIRT1 directly interacts with TERT, and promotes the nuclear localization and stability of TERT. Reverse transcriptase (RT) domain of TERT and N-terminus of SIRT1 mainly participated in their direct interaction. TERT, concomitantly expressed with intact SIRT1, exhibits nuclear localization, whereas TERT co-expressed with N-terminal-deleted SIRT1 remains in the cytosol. Furthermore, overexpression of SIRT1 enhances the nuclear localization and protein stability of TERT, akin to overexpression of deacetylase-inactive SIRT1, whereas N-terminal-deleted SIRT1 has no effect on TERT. These findings suggest a novel regulatory role of SIRT1 for TERT through direct interaction. This interaction provides new insights into the fields of aging, cancer, and genome stability governed by TERT and SIRT1.


Subject(s)
Sirtuin 1 , Telomerase , Animals , Humans , Mice , Cell Nucleus/metabolism , Enzyme Stability , HEK293 Cells , Protein Binding , Protein Stability , Sirtuin 1/metabolism , Sirtuin 1/genetics , Telomerase/metabolism , Telomerase/genetics
2.
Mol Cancer ; 22(1): 177, 2023 11 06.
Article in English | MEDLINE | ID: mdl-37932786

ABSTRACT

BACKGROUND: Although the development of BCR::ABL1 tyrosine kinase inhibitors (TKIs) rendered chronic myeloid leukemia (CML) a manageable condition, acquisition of drug resistance during blast phase (BP) progression remains a critical challenge. Here, we reposition FLT3, one of the most frequently mutated drivers of acute myeloid leukemia (AML), as a prognostic marker and therapeutic target of BP-CML. METHODS: We generated FLT3 expressing BCR::ABL1 TKI-resistant CML cells and enrolled phase-specific CML patient cohort to obtain unpaired and paired serial specimens and verify the role of FLT3 signaling in BP-CML patients. We performed multi-omics approaches in animal and patient studies to demonstrate the clinical feasibility of FLT3 as a viable target of BP-CML by establishing the (1) molecular mechanisms of FLT3-driven drug resistance, (2) diagnostic methods of FLT3 protein expression and localization, (3) association between FLT3 signaling and CML prognosis, and (4) therapeutic strategies to tackle FLT3+ CML patients. RESULTS: We reposition the significance of FLT3 in the acquisition of drug resistance in BP-CML, thereby, newly classify a FLT3+ BP-CML subgroup. Mechanistically, FLT3 expression in CML cells activated the FLT3-JAK-STAT3-TAZ-TEAD-CD36 signaling pathway, which conferred resistance to a wide range of BCR::ABL1 TKIs that was independent of recurrent BCR::ABL1 mutations. Notably, FLT3+ BP-CML patients had significantly less favorable prognosis than FLT3- patients. Remarkably, we demonstrate that repurposing FLT3 inhibitors combined with BCR::ABL1 targeted therapies or the single treatment with ponatinib alone can overcome drug resistance and promote BP-CML cell death in patient-derived FLT3+ BCR::ABL1 cells and mouse xenograft models. CONCLUSION: Here, we reposition FLT3 as a critical determinant of CML progression via FLT3-JAK-STAT3-TAZ-TEAD-CD36 signaling pathway that promotes TKI resistance and predicts worse prognosis in BP-CML patients. Our findings open novel therapeutic opportunities that exploit the undescribed link between distinct types of malignancies.


Subject(s)
Blast Crisis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Animals , Mice , Humans , Blast Crisis/drug therapy , Blast Crisis/genetics , Blast Crisis/pathology , Fusion Proteins, bcr-abl/genetics , Drug Resistance, Neoplasm/genetics , Signal Transduction , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Protein Kinase Inhibitors/pharmacology , fms-Like Tyrosine Kinase 3/metabolism
3.
Mol Cancer ; 22(1): 63, 2023 03 30.
Article in English | MEDLINE | ID: mdl-36991428

ABSTRACT

BACKGROUND: Although metastasis is the foremost cause of cancer-related death, a specialized mechanism that reprograms anchorage dependency of solid tumor cells into circulating tumor cells (CTCs) during metastatic dissemination remains a critical area of challenge. METHODS: We analyzed blood cell-specific transcripts and selected key Adherent-to-Suspension Transition (AST) factors that are competent to reprogram anchorage dependency of adherent cells into suspension cells in an inducible and reversible manner. The mechanisms of AST were evaluated by a series of in vitro and in vivo assays. Paired samples of primary tumors, CTCs, and metastatic tumors were collected from breast cancer and melanoma mouse xenograft models and patients with de novo metastasis. Analyses of single-cell RNA sequencing (scRNA-seq) and tissue staining were performed to validate the role of AST factors in CTCs. Loss-of-function experiments were performed by shRNA knockdown, gene editing, and pharmacological inhibition to block metastasis and prolong survival. RESULTS: We discovered a biological phenomenon referred to as AST that reprograms adherent cells into suspension cells via defined hematopoietic transcriptional regulators, which are hijacked by solid tumor cells to disseminate into CTCs. Induction of AST in adherent cells 1) suppress global integrin/ECM gene expression via Hippo-YAP/TEAD inhibition to evoke spontaneous cell-matrix dissociation and 2) upregulate globin genes that prevent oxidative stress to acquire anoikis resistance, in the absence of lineage differentiation. During dissemination, we uncover the critical roles of AST factors in CTCs derived from patients with de novo metastasis and mouse models. Pharmacological blockade of AST factors via thalidomide derivatives in breast cancer and melanoma cells abrogated CTC formation and suppressed lung metastases without affecting the primary tumor growth. CONCLUSION: We demonstrate that suspension cells can directly arise from adherent cells by the addition of defined hematopoietic factors that confer metastatic traits. Furthermore, our findings expand the prevailing cancer treatment paradigm toward direct intervention within the metastatic spread of cancer.


Subject(s)
Breast Neoplasms , Lung Neoplasms , Melanoma , Neoplastic Cells, Circulating , Mice , Animals , Humans , Female , Cell Line, Tumor , Neoplastic Cells, Circulating/pathology , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Melanoma/metabolism , Lung Neoplasms/pathology , Neoplasm Metastasis
4.
Proc Natl Acad Sci U S A ; 117(25): 14259-14269, 2020 06 23.
Article in English | MEDLINE | ID: mdl-32513743

ABSTRACT

The Hippo pathway controls organ size and tissue homeostasis by regulating cell proliferation and apoptosis. The LATS-mediated negative feedback loop prevents excessive activation of the effectors YAP/TAZ, maintaining homeostasis of the Hippo pathway. YAP and TAZ are hyperactivated in various cancer cells which lead to tumor growth. Aberrantly increased O-GlcNAcylation has recently emerged as a cause of hyperactivation of YAP in cancer cells. However, the mechanism, which induces hyperactivation of TAZ and blocks LATS-mediated negative feedback, remains to be elucidated in cancer cells. This study found that in breast cancer cells, abnormally increased O-GlcNAcylation hyperactivates YAP/TAZ and inhibits LATS2, a direct negative regulator of YAP/TAZ. LATS2 is one of the newly identified O-GlcNAcylated components in the MST-LATS kinase cascade. Here, we found that O-GlcNAcylation at LATS2 Thr436 interrupted its interaction with the MOB1 adaptor protein, which connects MST to LATS2, leading to activation of YAP/TAZ by suppressing LATS2 kinase activity. LATS2 is a core component in the LATS-mediated negative feedback loop. Thus, this study suggests that LATS2 O-GlcNAcylation is deeply involved in tumor growth by playing a critical role in dysregulation of the Hippo pathway in cancer cells.


Subject(s)
Protein Serine-Threonine Kinases/metabolism , Signal Transduction , Tumor Suppressor Proteins/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Apoptosis , Cell Proliferation , HEK293 Cells , Hippo Signaling Pathway , Homeostasis , Humans , Phosphorylation
5.
Am J Hum Genet ; 104(3): 439-453, 2019 03 07.
Article in English | MEDLINE | ID: mdl-30773278

ABSTRACT

SPONASTRIME dysplasia is a rare, recessive skeletal dysplasia characterized by short stature, facial dysmorphism, and aberrant radiographic findings of the spine and long bone metaphysis. No causative genetic alterations for SPONASTRIME dysplasia have yet been determined. Using whole-exome sequencing (WES), we identified bi-allelic TONSL mutations in 10 of 13 individuals with SPONASTRIME dysplasia. TONSL is a multi-domain scaffold protein that interacts with DNA replication and repair factors and which plays critical roles in resistance to replication stress and the maintenance of genome integrity. We show here that cellular defects in dermal fibroblasts from affected individuals are complemented by the expression of wild-type TONSL. In addition, in vitro cell-based assays and in silico analyses of TONSL structure support the pathogenicity of those TONSL variants. Intriguingly, a knock-in (KI) Tonsl mouse model leads to embryonic lethality, implying the physiological importance of TONSL. Overall, these findings indicate that genetic variants resulting in reduced function of TONSL cause SPONASTRIME dysplasia and highlight the importance of TONSL in embryonic development and postnatal growth.


Subject(s)
Fibroblasts/pathology , Genes, Lethal , Mutation , NF-kappa B/genetics , Osteochondrodysplasias/pathology , Adolescent , Adult , Animals , Cells, Cultured , Child , Child, Preschool , DNA Damage , Dermis/metabolism , Dermis/pathology , Female , Fibroblasts/metabolism , Humans , Infant , Infant, Newborn , Mice , Mice, Inbred C57BL , Osteochondrodysplasias/genetics , Exome Sequencing/methods , Young Adult
6.
Biochem Biophys Res Commun ; 514(4): 1087-1092, 2019 07 05.
Article in English | MEDLINE | ID: mdl-31097220

ABSTRACT

Etoposide-induced 2.4 kb transcript (EI24, also known as PIG8) is a p53 target gene involved in cell growth suppression and apoptosis and known to be frequently altered in human cancers. Although EI24 expression is decreased in various cancers and is associated with colorectal cancer progression and metastasis, the physiological function of EI24 in colorectal cancer is yet unclear. We generated an Ei24 conditional transgenic (Tg) mouse to study the therapeutic effects of Ei24 in vivo and evaluated whether Ei24 plays a role of a tumor suppressor using Ei24 Tg mouse crossed with ApcMin/+ mouse, which develops multiple intestinal adenomas. The overexpression of Ei24 failed to cause any notable difference in the number of polyps, lengths of the intestine and spleen, and survival rate between ApcMin/+ and ApcMin/+Ei24 Tg mice. Ei24 plays no significant role in colon cancer caused by the substitutional mutation of Apc in mice. Therefore, our result dismisses the hypothesized direct link between ApcMin/+ mutation and Ei24 expression in colorectal cancer model.


Subject(s)
Adenomatous Polyposis Coli Protein/genetics , Apoptosis Regulatory Proteins/genetics , Colorectal Neoplasms/genetics , Disease Models, Animal , Nuclear Proteins/genetics , Adenomatous Polyposis Coli Protein/metabolism , Animals , Apoptosis Regulatory Proteins/metabolism , Carcinogenesis/genetics , Colorectal Neoplasms/metabolism , Mice , Mice, Inbred C57BL , Mice, Transgenic , Mutation , Nuclear Proteins/metabolism
8.
Transgenic Res ; 27(3): 241-251, 2018 06.
Article in English | MEDLINE | ID: mdl-29594927

ABSTRACT

Immunodeficient mice are widely used for pre-clinical studies to understand various human diseases. Here, we report the generation of four immunodeficient mouse models using CRISPR/Cas9 system without inserting any foreign gene sequences such as NeoR cassettes and their characterization. By eliminating any possible effects of adding a NeoR cassette, our mouse models may allow us to better elucidate the in vivo functions of each gene. Our FVB-Rag2-/-, B6-Rag2-/-, and BALB/c-Prkdc-/- mice showed phenotypes similar to those of the earlier immunodeficient mouse models, including a lack of mature B cells and T cells and an increase in the number of CD45+DX-5+ natural killer cells. However, B6-Il2rg-/- mice had a unique phenotype, with a lack of mature B cells, increased number of T cells, and decreased number of natural killer cells. Additionally, serum immunoglobulin levels in all four immunodeficient mouse models were significantly reduced when compared to those in wild-type mice with the exception of IgM in B6-Il2rg-/- mice. These results indicate that our immunodeficient mouse models are a robust tool for in vivo studies of the immune system and will provide new insights into the variation in phenotypic outcomes resulting from different gene-targeting methodologies.


Subject(s)
CRISPR-Cas Systems/genetics , Gene Knockout Techniques/methods , Mice, Knockout/genetics , Mice, SCID/genetics , Animals , Disease Models, Animal , Gene Targeting/methods , Humans , Mice , Mice, Inbred BALB C , Phenotype , T-Lymphocytes/immunology
9.
J Cell Physiol ; 232(8): 2083-2093, 2017 Aug.
Article in English | MEDLINE | ID: mdl-27648923

ABSTRACT

Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, an RNA-dependent DNA polymerase that elongates telomeric DNA. hTERT displays several extra-telomeric functions that are independent of its telomere-regulatory function, including tumor progression, and neuronal cell death regulation. In this study, we evaluated these additional hTERT non-telomeric functions. We determined that hTERT interacts with several 19S and 20S proteasome subunits. The 19S regulatory particle and 20S core particle are part of 26S proteasome complex, which plays a central role in ubiquitin-dependent proteolysis. In addition, hTERT positively regulated 26S proteasome activity independent of its enzymatic activity. Moreover, hTERT enhanced subunit interactions, which may underlie hTERT's ability of hTERT to stimulate the 26S proteasome. Furthermore, hTERT displayed cytoprotective effect against ER stress via the activation of 26S proteasome in acute myeloid leukemia cells. Our data suggest that hTERT acts as a novel chaperone to promote 26S proteasome assembly and maintenance. J. Cell. Physiol. 232: 2083-2093, 2017. © 2016 Wiley Periodicals, Inc.


Subject(s)
Molecular Chaperones/metabolism , Proteasome Endopeptidase Complex/metabolism , Telomerase/metabolism , Animals , Cell Death/drug effects , Endoplasmic Reticulum Stress/drug effects , Fibroblasts/enzymology , HeLa Cells , Humans , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/enzymology , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Mice, Knockout , Molecular Chaperones/genetics , Proteasome Endopeptidase Complex/drug effects , Proteasome Inhibitors/pharmacology , Protein Binding , Proteolysis , RNA/genetics , RNA/metabolism , RNA Interference , RNA-Binding Proteins , Telomerase/genetics , Time Factors , Transfection , Tunicamycin/pharmacology , Ubiquitination
10.
Genome Res ; 24(1): 125-31, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24253447

ABSTRACT

RNA-guided endonucleases (RGENs), derived from the prokaryotic Type II CRISPR-Cas system, enable targeted genome modification in cells and organisms. Here we describe the establishment of gene-knockout mice and zebrafish by the injection of RGENs as Cas9 protein:guide RNA complexes or Cas9 mRNA plus guide RNA into one-cell-stage embryos of both species. RGENs efficiently generated germline transmittable mutations in up to 93% of newborn mice with minimal toxicity. RGEN-induced mutations in the mouse Prkdc gene that encodes an enzyme critical for DNA double-strand break repair resulted in immunodeficiency both in F0 and F1 mice. We propose that RGEN-mediated mutagenesis in animals will greatly expedite the creation of genetically engineered model organisms, accelerating functional genomic research.


Subject(s)
CRISPR-Associated Proteins/metabolism , Endonucleases/genetics , Mutagenesis , Nuclear Proteins/genetics , Animals , Animals, Newborn/genetics , Clustered Regularly Interspaced Short Palindromic Repeats , Embryo, Mammalian , Embryo, Nonmammalian , Endonucleases/metabolism , Forkhead Transcription Factors/metabolism , Gene Knockout Techniques , Genome , Germ-Line Mutation , Mice , Mice, Inbred BALB C , Mice, Knockout , Nuclear Proteins/metabolism , Phenotype , Zebrafish/genetics , Zebrafish/metabolism , RNA, Small Untranslated
11.
Biochem Biophys Res Commun ; 478(3): 1198-204, 2016 09 23.
Article in English | MEDLINE | ID: mdl-27545609

ABSTRACT

Telomerase is a reverse transcriptase that consists of the telomerase RNA component (TERC) and the reverse transcriptase catalytic subunit (TERT) and specializes in the elongation of telomere ends. New evidence suggests that beyond classical telomere maintenance, TERT also possesses telomere length-independent functions that are executed via interaction with other binding proteins. One such reported TERT-interacting proteins is mTOR, a master nutrient sensor that is upregulated in several cancers; however, the physiological implications of the TERT-mTOR interaction in normal cellular processes as well as in tumorigenesis are poorly understood. Here, we report that TERT inhibits the kinase activity of mTOR complex 1 (mTORC1) in multiple cell lines, resulting in the activation of autophagy under both basal and amino acid-deprived conditions. Furthermore, TERT-deficient cells display the inability to properly execute the autophagy flux. Functionally, TERT-induced autophagy provides a survival advantage to cells in nutrient-deprived conditions. Collectively, these findings support a model in which gain of TERT function modulates mTORC1 activity and induces autophagy, which is required for metabolic rewiring to scavenge the nutrients necessary for fueling cancer cell growth in challenging tumor microenvironments.


Subject(s)
Amino Acids/deficiency , Autophagy , Multiprotein Complexes/metabolism , TOR Serine-Threonine Kinases/metabolism , Telomerase/metabolism , Amino Acids/metabolism , Animals , Cell Survival , Embryo, Mammalian/cytology , Fibroblasts/metabolism , HEK293 Cells , Hep G2 Cells , Humans , Mechanistic Target of Rapamycin Complex 1 , Mice, Knockout
12.
Exp Dermatol ; 25(8): 630-5, 2016 08.
Article in English | MEDLINE | ID: mdl-27061078

ABSTRACT

Extracellular superoxide dismutase (EC-SOD) is an enzyme that catalyses the dismutation of superoxide anions. It has multiple functions, such as reactive oxygen species scavenging, anti-angiogenic, anti-inflammatory, antichemotatic and antitumor activities. Recently, we demonstrated that EC-SOD inhibits ovalbumin-induced allergic airway inflammation in mice. However, the anti-allergic effect of EC-SOD on skin tissue and the role of EC-SOD in mast cells, which are important for allergic responses, have not been well studied. In this study, we investigated whether EC-SOD can alleviate atopic dermatitis in mice and inhibit mast cell activation. Treatment with human recombinant EC-SOD ameliorated house dust mite-induced atopic dermatitis in mice. Furthermore, the levels of pro-allergic cytokine gene expression and histamine release increased in EC-SOD KO mast cells and decreased in EC-SOD overexpressing mast cells, suggesting that EC-SOD inhibits mast cell activation. Consistently, a passive cutaneous anaphylaxis experiment showed more blood leakage from EC-SOD KO mouse ear skin, implying that the lack of EC-SOD increases allergic responses. These results suggest that EC-SOD inhibits mast cell activation and atopic dermatitis and that the loss of EC-SOD causes more severe allergic responses, implying that EC-SOD might be a good drug candidate for treatment of allergic disorders, such as atopic dermatitis.


Subject(s)
Dermatitis, Atopic/drug therapy , Mast Cells/drug effects , Pyroglyphidae/immunology , Superoxide Dismutase/therapeutic use , Animals , Dermatitis, Atopic/immunology , Drug Evaluation, Preclinical , Mice, Inbred C57BL , Mice, Knockout , Passive Cutaneous Anaphylaxis/drug effects , Superoxide Dismutase/pharmacology
13.
Proc Natl Acad Sci U S A ; 110(14): 5677-82, 2013 Apr 02.
Article in English | MEDLINE | ID: mdl-23509283

ABSTRACT

Pulsatile release of hypothalamic gonadotropin-releasing hormone (GnRH) is essential for pituitary gonadotrope function. Although the importance of pulsatile GnRH secretion has been recognized for several decades, the mechanisms underlying GnRH pulse generation in hypothalamic neural networks remain elusive. Here, we demonstrate the ultradian rhythm of GnRH gene transcription in single GnRH neurons using cultured hypothalamic slices prepared from transgenic mice expressing a GnRH promoter-driven destabilized luciferase reporter. Although GnRH promoter activity in each GnRH neuron exhibited an ultradian pattern of oscillations with a period of ∼10 h, GnRH neuronal cultures exhibited partially synchronized bursts of GnRH transcriptional activity at ∼2-h intervals. Surprisingly, pulsatile administration of kisspeptin, a potent GnRH secretagogue, evoked dramatic synchronous activation of GnRH gene transcription with robust stimulation of pulsatile GnRH secretion. We also addressed the issue of hierarchical interaction between the circadian and ultradian rhythms by using Bmal1-deficient mice with defective circadian clocks. The circadian molecular oscillator barely affected basal ultradian oscillation of GnRH transcription but was heavily involved in kisspeptin-evoked responses of GnRH neurons. In conclusion, we have clearly shown synchronous bursts of GnRH gene transcription in the hypothalamic GnRH neuronal population in association with episodic neurohormone secretion, thereby providing insight into GnRH pulse generation.


Subject(s)
Gene Expression Regulation/physiology , Gonadotropin-Releasing Hormone/metabolism , Hypothalamus/metabolism , Kisspeptins/pharmacology , Nerve Net/metabolism , Transcription, Genetic/physiology , ARNTL Transcription Factors/deficiency , Activity Cycles/physiology , Animals , Gene Expression Regulation/drug effects , Kisspeptins/administration & dosage , Luciferases , Mice , Mice, Transgenic , Neurons/metabolism , Pulsatile Flow , Transcription, Genetic/drug effects
14.
Nat Genet ; 39(1): 99-105, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17143283

ABSTRACT

Telomere shortening limits the proliferative lifespan of human cells by activation of DNA damage pathways, including upregulation of the cell cycle inhibitor p21 (encoded by Cdkn1a, also known as Cip1 and Waf1)) (refs. 1-5). Telomere shortening in response to mutation of the gene encoding telomerase is associated with impaired organ maintenance and shortened lifespan in humans and in mice. The in vivo function of p21 in the context of telomere dysfunction is unknown. Here we show that deletion of p21 prolongs the lifespan of telomerase-deficient mice with dysfunctional telomeres. p21 deletion improved hematolymphopoiesis and the maintenance of intestinal epithelia without rescuing telomere function. Moreover, deletion of p21 rescued proliferation of intestinal progenitor cells and improved the repopulation capacity and self-renewal of hematopoietic stem cells from mice with dysfunctional telomeres. In these mice, apoptotic responses remained intact, and p21 deletion did not accelerate chromosomal instability or cancer formation. This study provides experimental evidence that telomere dysfunction induces p21-dependent checkpoints in vivo that can limit longevity at the organismal level.


Subject(s)
Cyclin-Dependent Kinase Inhibitor p21/genetics , Gene Deletion , Longevity/genetics , Neoplasms/genetics , Stem Cells/physiology , Telomere/physiology , Animals , Cells, Cultured , Crosses, Genetic , Disease Progression , Intestines/cytology , Mice , Mice, Inbred C57BL , Mice, Knockout , Neoplasms/pathology , Telomerase/genetics
15.
Methods ; 69(1): 85-93, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-24561165

ABSTRACT

The use of engineered nucleases in one-cell stage mouse embryos is emerging as an efficient alternative to conventional gene targeting in mouse embryonic stem (ES) cells. These nucleases are designed or reprogrammed to specifically induce double strand breaks (DSBs) at a desired genomic locus, and efficiently introduce mutations by both error-prone and error-free DNA repair mechanisms. Since these mutations frequently result in the loss or alteration of gene function by inserting, deleting, or substituting nucleotide sequences, engineered nucleases are enabling us to efficiently generate gene knockout and knockin mice. Three kinds of engineered endonucleases have been developed and successfully applied to the generation of mutant mice: zinc-finger nuclease (ZFNs), transcription activator-like effector nucleases (TALENs) and RNA-guided endonucleases (RGENs). Based on recent advances, here we provide experimentally validated, detailed guidelines for generating non-homologous end-joining (NHEJ)-mediated mutant mice by microinjecting TALENs and RGENs into the cytoplasm or the pronucleus of one-cell stage mouse embryos.


Subject(s)
Gene Knockout Techniques , Mice, Knockout/genetics , Animals , Caspase 9/genetics , DNA End-Joining Repair , Embryo, Mammalian , Endonucleases/chemistry , Endonucleases/genetics , Microinjections
16.
J Biol Chem ; 288(43): 31261-7, 2013 Oct 25.
Article in English | MEDLINE | ID: mdl-24014029

ABSTRACT

The deficiency of retinoblastoma (Rb) gene deregulates E2F transcription factors and thus induces E2F target genes directly or p53 target genes indirectly via mouse p19(Arf) (or p14(ARF) in humans), an E2F target gene. Here, we identified that etoposide-induced 2.4 mRNA (Ei24)/p53-induced gene 8 (Pig8), a p53 target gene involved in apoptosis and autophagy, was up-regulated in Rb(-/-) mouse embryonic fibroblasts (MEFs). The Ei24 promoter was activated by E2F1 via multiple E2F-responsive elements, independently of the previously reported p53-responsive element. Chromatin immunoprecipitation assays revealed that E2F1 directly acts on the mouse Ei24 promoter. We observed that Ei24 expression was suppressed in p53(-/-) MEFs upon UVC irradiation, which was exacerbated in p53(-/-) E2f1(-/-) MEFs, supporting the positive role of E2F1 on Ei24 transcription. Furthermore, Ei24 knockdown sensitized p53(-/-) MEFs against UVC irradiation. Together, our data indicate that Ei24 is a novel E2F target gene contributing to the survival of p53-deficient cells upon UVC irradiation and thus may have a potential significance as a therapeutic target of certain chemotherapy for treating p53-deficient tumors.


Subject(s)
Apoptosis Regulatory Proteins/metabolism , E2F1 Transcription Factor/metabolism , Nuclear Proteins/metabolism , Tumor Suppressor Protein p53/metabolism , Ultraviolet Rays/adverse effects , Animals , Apoptosis Regulatory Proteins/genetics , Cell Death/genetics , Cell Death/radiation effects , Cell Survival/genetics , Cell Survival/radiation effects , E2F1 Transcription Factor/genetics , Humans , Mice , Mice, Knockout , NIH 3T3 Cells , Neoplasms/drug therapy , Neoplasms/genetics , Neoplasms/metabolism , Neoplasms/pathology , Nuclear Proteins/genetics , Response Elements/genetics , Retinoblastoma Protein/genetics , Retinoblastoma Protein/metabolism , Transcription, Genetic/genetics , Transcription, Genetic/radiation effects , Tumor Suppressor Protein p53/genetics
17.
J Biol Chem ; 288(9): 6488-97, 2013 Mar 01.
Article in English | MEDLINE | ID: mdl-23316056

ABSTRACT

Cilia in ciliated cells consist of protruding structures that sense mechanical and chemical signals from the extracellular environment. Cilia are assembled with variety molecules via a process known as intraflagellar transport (IFT). What controls the length of cilia in ciliated cells is critical to understand ciliary disease such as autosomal dominant polycystic kidney disease, which involves abnormally short cilia. But this control mechanism is not well understood. Previously, multiple tubular cysts have been observed in the kidneys of max-interacting protein 1 (Mxi1)-deficient mice aged 6 months or more. Here, we clarified the relationship between Mxi1 inactivation and cilia disassembly. Cilia phenotypes were observed in kidneys of Mxi1-deficient mice using scanning electron microscopy to elucidate the effect of Mxi1 on renal cilia phenotype, and cilia disassembly was observed in Mxi1-deficient kidney. In addition, genes related to cilia were validated in vitro and in vivo using quantitative PCR, and Ift20 was selected as a candidate gene in this study. The length of cilium decreased, and p-ERK level induced by a cilia defect increased in kidneys of Mxi1-deficient mice. Ciliogenesis of Mxi1-deficient mouse embryonic fibroblasts (MEFs) decreased, and this abnormality was restored by Mxi1 transfection in Mxi1-deficient MEFs. We confirmed that ciliogenesis and Ift20 expression were regulated by Mxi1 in vitro. We also determined that Mxi1 regulates Ift20 promoter activity via Ets-1 binding to the Ift20 promoter. These results indicate that inactivating Mxi1 induces ciliary defects in polycystic kidney.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Carrier Proteins/biosynthesis , Kidney/metabolism , Polycystic Kidney, Autosomal Dominant/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Carrier Proteins/genetics , Cells, Cultured , Cilia/metabolism , Cilia/ultrastructure , Embryo, Mammalian/metabolism , Embryo, Mammalian/ultrastructure , Fibroblasts/metabolism , Fibroblasts/ultrastructure , Gene Expression Regulation/genetics , Kidney/ultrastructure , Mice , Mice, Mutant Strains , Microscopy, Electron, Scanning , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/pathology , Polymerase Chain Reaction , Proto-Oncogene Protein c-ets-1/genetics , Proto-Oncogene Protein c-ets-1/metabolism , Response Elements/genetics , Tumor Suppressor Proteins/genetics
18.
EMBO Rep ; 13(2): 150-6, 2012 Feb 01.
Article in English | MEDLINE | ID: mdl-22222206

ABSTRACT

Sqstm1/p62 functions in the non-canonical activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2). However, its physiological relevance is not certain. Here, we show that p62(-/-) mice exhibited an accelerated presentation of ageing phenotypes, and tissues from these mice created a pro-oxidative environment owing to compromised mitochondrial electron transport. Accordingly, mitochondrial function rapidly declined with age in p62(-/-) mice. In addition, p62 enhanced basal Nrf2 activity, conferring a higher steady-state expression of NAD(P)H dehydrogenase, quinone 1 (Nqo1) to maintain mitochondrial membrane potential and, thereby, restrict excess oxidant generation. Together, the p62-Nrf2-Nqo1 cascade functions to assure mammalian longevity by stabilizing mitochondrial integrity.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Cytoskeletal Proteins/metabolism , Heat-Shock Proteins/metabolism , Longevity/physiology , Mammals/physiology , Mitochondria/metabolism , NAD(P)H Dehydrogenase (Quinone)/metabolism , NF-E2-Related Factor 2/metabolism , Adaptor Proteins, Signal Transducing/deficiency , Animals , Autophagy , Female , Heat-Shock Proteins/deficiency , Kelch-Like ECH-Associated Protein 1 , Male , Mice , Oxidation-Reduction , Sequestosome-1 Protein , Signal Transduction
19.
J Control Release ; 373: 55-69, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-38971428

ABSTRACT

Immunogenic cell death (ICD) holds the potential for in situ tumor vaccination while concurrently eradicating tumors and stimulating adaptive immunity. Most ICD inducers, however, elicit insufficient immune responses due to negative feedback against ICD biomarkers, limited infiltration of antitumoral immune cells, and the immunosuppressive tumor micro-environment (TME). Recent findings highlight the pivotal roles of stimulators of interferon gene (STING) activation, particularly in stimulating antigen-presenting cells (APCs) and TME reprogramming, addressing ICD limitations. Herein, we introduced 'tumor phagocytosis-driven STING activation', which involves the activation of STING in APCs during the recognition of ICD-induced cancer cells. We developed a polypeptide-based nanocarrier encapsulating both doxorubicin (DOX) and diABZI STING agonist 3 (dSA3) to facilitate this hypothesis in vitro and in vivo. After systemic administration, nanoparticles predominantly accumulated in tumor tissue and significantly enhanced anticancer efficacy by activating tumor phagocytosis-driven STING activation in MC38 and TC1 tumor models. Immunological activation of APCs occurred within 12 h, subsequently leading to the activation of T cells within 7 days, observed in both the TME and spleen. Furthermore, surface modification of nanoparticles with cyclic RGD (cRGD) moieties, which actively target integrin αvß3, enhances tumor accumulation and eradication, thereby verifying the establishment of systemic immune memory. Collectively, this study proposes the concept of tumor phagocytosis-driven STING activation and its effectiveness in generating short-term and long-term immune responses.

20.
Nat Commun ; 15(1): 4052, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38744820

ABSTRACT

Obesity has emerged as a prominent risk factor for the development of malignant tumors. However, the existing literature on the role of adipocytes in the tumor microenvironment (TME) to elucidate the correlation between obesity and cancer remains insufficient. Here, we aim to investigate the formation of cancer-associated adipocytes (CAAs) and their contribution to tumor growth using mouse models harboring dysfunctional adipocytes. Specifically, we employ adipocyte-specific BECN1 KO (BaKO) mice, which exhibit lipodystrophy due to dysfunctional adipocytes. Our results reveal the activation of YAP/TAZ signaling in both CAAs and BECN1-deficient adipocytes, inducing adipocyte dedifferentiation and formation of a malignant TME. The additional deletion of YAP/TAZ from BaKO mice significantly restores the lipodystrophy and inflammatory phenotypes, leading to tumor regression. Furthermore, mice fed a high-fat diet (HFD) exhibit decreased BECN1 and increased YAP/TAZ expression in their adipose tissues. Treatment with the YAP/TAZ inhibitor, verteporfin, suppresses tumor progression in BaKO and HFD-fed mice, highlighting its efficacy against mice with metabolic dysregulation. Overall, our findings provide insights into the key mediators of CAA and their significance in developing a TME, thereby suggesting a viable approach targeting adipocyte homeostasis to suppress cancer growth.


Subject(s)
Adaptor Proteins, Signal Transducing , Adipocytes , Diet, High-Fat , Mice, Knockout , Transcriptional Coactivator with PDZ-Binding Motif Proteins , Tumor Microenvironment , YAP-Signaling Proteins , Animals , Mice , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adipocytes/metabolism , Adipocytes/pathology , Cell Cycle Proteins/metabolism , Cell Cycle Proteins/genetics , Cell Transformation, Neoplastic/metabolism , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/pathology , Diet, High-Fat/adverse effects , Disease Progression , Lipodystrophy/metabolism , Lipodystrophy/pathology , Lipodystrophy/genetics , Mice, Inbred C57BL , Neoplasms/metabolism , Neoplasms/pathology , Neoplasms/genetics , Obesity/metabolism , Obesity/pathology , Signal Transduction , Trans-Activators/metabolism , Trans-Activators/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Verteporfin/pharmacology , YAP-Signaling Proteins/metabolism
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