Regulation of mouse lens fiber cell development and differentiation by the Maf gene

Maf is a basic domain/leucine zipper domain protein originally identified as a proto-oncogene whose consensus target site in vitro, the T-MARE, is an extended version of an AP-1 site normally recognized by Fos and Jun. Maf and the closely related family members Neural retina leucine zipper (Nrl), L-Maf, and Krml1/MafB have been implicated in a wide variety of developmental and physiologic roles; however, mutations in vivo have been described only for Krml1/MafB, in which a loss-of-function causes abnormalities in hindbrain development due to failure to activate the Hoxa3 and Hoxb3 genes. We have used gene targeting to replace Maf coding sequences with those of lacZ, and have carried out a comprehensive analysis of embryonic expression and the homozygous mutant phenotype in the eye. Maf is expressed in the lens vesicle after invagination, and becomes highly upregulated in the equatorial zone, the site at which self-renewing anterior epithelial cells withdraw from the cell cycle and terminally differentiate into posterior fiber cells. Posterior lens cells in Maf(lacZ) mutant mice exhibit failure of elongation at embryonic day 11.5, do not express (α)A- and all of the (beta)-crystallin genes, and display inappropriately high levels of DNA synthesis. This phenotype partially overlaps with those reported for gene targeting of Prox1 and Sox1; however, expression of these genes is grossly normal, as is expression of Eya1, Eya2, Pax6, and Sox2. Recombinant Maf protein binds to T-MARE sites in the (alpha)A-, (beta)B2-, and (beta)A4-crystallin promoters but fails to bind to a point mutation in the (alpha)A-crystallin promoter that has been shown previously to be required for promoter function. Our results indicate that Maf directly activates many if not all of the (beta)-crystallin genes, and suggest a model for coordinating cell cycle withdrawal with terminal differentiation.

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β-elemene alleviates airway stenosis via the ILK/Akt pathway modulated by MIR143HG sponging miR-1275

Cellular & Molecular Biology Letters ◽

10.1186/s11658-021-00261-0 ◽

2021 ◽

Vol 26 (1) ◽

Author(s):

Guoying Zhang ◽

Cheng Xue ◽

Yiming Zeng

Keyword(s):

Cell Cycle ◽

Cell Viability ◽

Cell Model ◽

Protective Efficacy ◽

Rabbit Model ◽

Akt Pathway ◽

Loss Of Function ◽

Airway Stenosis

Abstract Background We have previously found that β-elemene could inhibit the viability of airway granulation fibroblasts and prevent airway hyperplastic stenosis. This study aimed to elucidate the underlying mechanism and protective efficacy of β-elemene in vitro and in vivo. Methods Microarray and bioinformatic analysis were used to identify altered pathways related to cell viability in a β-elemene-treated primary cell model and to construct a β-elemene-altered ceRNA network modulating the target pathway. Loss of function and gain of function approaches were performed to examine the role of the ceRNA axis in β-elemene's regulation of the target pathway and cell viability. Additionally, in a β-elemene-treated rabbit model of airway stenosis, endoscopic and histological examinations were used to evaluate its therapeutic efficacy and further verify its mechanism of action. Results The hyperactive ILK/Akt pathway and dysregulated LncRNA-MIR143HG, which acted as a miR-1275 ceRNA to modulate ILK expression, were suppressed in β-elemene-treated airway granulation fibroblasts; β-elemene suppressed the ILK/Akt pathway via the MIR143HG/miR-1275/ILK axis. Additionally, the cell cycle and apoptotic phenotypes of granulation fibroblasts were altered, consistent with ILK/Akt pathway activity. In vivo application of β-elemene attenuated airway granulation hyperplasia and alleviated scar stricture, and histological detections suggested that β-elemene's effects on the MIR143HG/miR-1275/ILK axis and ILK/Akt pathway were in line with in vitro findings. Conclusions MIR143HG and ILK may act as ceRNA to sponge miR-1275. The MIR143HG/miR-1275/ILK axis mediates β-elemene-induced cell cycle arrest and apoptosis of airway granulation fibroblasts by modulating the ILK/Akt pathway, thereby inhibiting airway granulation proliferation and ultimately alleviating airway stenosis.

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p53 upregulated by HIF-1α promotes hypoxia-induced G2/M arrest and renal fibrosis in vitro and in vivo

Journal of Molecular Cell Biology ◽

10.1093/jmcb/mjy042 ◽

2018 ◽

Vol 11 (5) ◽

pp. 371-382 ◽

Cited By ~ 15

Author(s):

Limin Liu ◽

Peng Zhang ◽

Ming Bai ◽

Lijie He ◽

Lei Zhang ◽

...

Keyword(s):

Cell Cycle ◽

Transcriptional Activation ◽

Renal Fibrosis ◽

Intraperitoneal Administration ◽

Luciferase Reporter ◽

Loss Of Function ◽

P53 Expression ◽

Tubular Cells

Abstract Hypoxia plays an important role in the genesis and progression of renal fibrosis. The underlying mechanisms, however, have not been sufficiently elucidated. We examined the role of p53 in hypoxia-induced renal fibrosis in cell culture (human and rat renal tubular epithelial cells) and a mouse unilateral ureteral obstruction (UUO) model. Cell cycle of tubular cells was determined by flow cytometry, and the expression of profibrogenic factors was determined by RT-PCR, immunohistochemistry, and western blotting. Chromatin immunoprecipitation and luciferase reporter experiments were performed to explore the effect of HIF-1α on p53 expression. We showed that, in hypoxic tubular cells, p53 upregulation suppressed the expression of CDK1 and cyclins B1 and D1, leading to cell cycle (G2/M) arrest (or delay) and higher expression of TGF-β, CTGF, collagens, and fibronectin. p53 suppression by siRNA or by a specific p53 inhibitor (PIF-α) triggered opposite effects preventing the G2/M arrest and profibrotic changes. In vivo experiments in the UUO model revealed similar antifibrotic results following intraperitoneal administration of PIF-α (2.2 mg/kg). Using gain-of-function, loss-of-function, and luciferase assays, we further identified an HRE3 region on the p53 promoter as the HIF-1α-binding site. The HIF-1α–HRE3 binding resulted in a sharp transcriptional activation of p53. Collectively, we show the presence of a hypoxia-activated, p53-responsive profibrogenic pathway in the kidney. During hypoxia, p53 upregulation induced by HIF-1α suppresses cell cycle progression, leading to the accumulation of G2/M cells, and activates profibrotic TGF-β and CTGF-mediated signaling pathways, causing extracellular matrix production and renal fibrosis.

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Upregulation of SGOL2 Predicts Poor Prognosis and Facilitates Hepatocellular Carcinoma Progression via Dysregulating the Cell Cycle by Directly Activating MAD2

10.21203/rs.3.rs-560609/v1 ◽

2021 ◽

Author(s):

Qingqing Hu ◽

Xiaochu Hu ◽

Yalei Zhao ◽

Lingjian Zhang ◽

Ya Yang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Cell Cycle ◽

The Cancer Genome Atlas ◽

Loss Of Function ◽

Protein Levels ◽

Cancer Genome Atlas ◽

Centromeric Protein ◽

Hcc Cells

Abstract Background: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Shugoshin-like protein 2 (SGOL2) is a centromeric protein that ensures the correct and orderly process of mitosis by protecting and maintaining centripetal adhesions during meiosis and mitosis. However, the role of SGOL2 in cancer is not well understood. Methods: The mRNA and protein levels of SGOL2 and survival analysis were conducted in The Cancer Genome Atlas (TCGA) and further validated in 2 independent cohorts. Differential genes correlated with SGOL2 and mitotic arrest deficient 2 like 1 (MAD2) were obtained using LinkedOmics. Subsequently, loss-of-function and rescue assays were carried out in vitro and in vivo to assess the functions of SGOL2 in hepatic tumorigenisis. Findings: We found that SGOL2 was significantly overexpressed in HCC and predicted unfavorable overall survival in HCC patients. Next, we identified 47 differentially expressed genes positively correlated with both SGOL2 and MAD2 to be mainly involved in the cell cycle. In addition, SGOL2 downregulation suppressed the migration, invasion, proliferation, stemness and EMT of HCC cells and inhibited tumorigenesis in vivo. Furthermore, SGOL2 promoted tumor proliferation by activating MAD2-induced cell cycle dysregulation, which could be reversed by the MAD2 inhibitor M2I-1. We also proved that SGOL2 activated MAD2 by directly binding with MAD2. Conclusions: The results of this study showed that SGOL2 acts as an oncogene in HCC cells by directly activating MAD2 and then dysregulating the cell cycle, thereby providing a potential target for HCC patients in the future.

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Rapid Generation of Long Noncoding RNA Knockout Mice Using CRISPR/Cas9 Technology

Non-Coding RNA ◽

10.3390/ncrna5010012 ◽

2019 ◽

Vol 5 (1) ◽

pp. 12 ◽

Cited By ~ 7

Author(s):

Nils R. Hansmeier ◽

Pia J. M. Widdershooven ◽

Sajjad Khani ◽

Jan-Wilhelm Kornfeld

Keyword(s):

Gene Targeting ◽

Mouse Models ◽

Noncoding Rna ◽

Genome Engineering ◽

Model Organisms ◽

Specific Gene ◽

Loss Of Function ◽

Mouse Lines

In recent years, long noncoding RNAs (lncRNAs) have emerged as multifaceted regulators of gene expression, controlling key developmental and disease pathogenesis processes. However, due to the paucity of lncRNA loss-of-function mouse models, key questions regarding the involvement of lncRNAs in organism homeostasis and (patho)-physiology remain difficult to address experimentally in vivo. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 platform provides a powerful genome-editing tool and has been successfully applied across model organisms to facilitate targeted genetic mutations, including Caenorhabditis elegans, Drosophila melanogaster, Danio rerio and Mus musculus. However, just a few lncRNA-deficient mouse lines have been created using CRISPR/Cas9-mediated genome engineering, presumably due to the need for lncRNA-specific gene targeting strategies considering the absence of open-reading frames in these loci. Here, we describe a step-wise procedure for the generation and validation of lncRNA loss-of-function mouse models using CRISPR/Cas9-mediated genome engineering. In a proof-of-principle approach, we generated mice deficient for the liver-enriched lncRNA Gm15441, which we found downregulated during development of metabolic disease and induced during the feeding/fasting transition. Further, we discuss guidelines for the selection of lncRNA targets and provide protocols for in vitro single guide RNA (sgRNA) validation, assessment of in vivo gene-targeting efficiency and knockout confirmation. The procedure from target selection to validation of lncRNA knockout mouse lines can be completed in 18–20 weeks, of which <10 days hands-on working time is required.

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

Cell Death Discovery ◽

10.1038/s41420-021-00440-0 ◽

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.

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DIPG-14. TARGETING POLO-LIKE KINASE 1 IN COMBINATION WITH KEY ONCOGENIC DRIVERS IN DIPG: FROM SINGLE AGENT TO COMBINATION STRATEGIES

Neuro-Oncology ◽

10.1093/neuonc/noaa222.064 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii289-iii289

Author(s):

Laura Franshaw ◽

Elisha Hayden ◽

Swapna Joshi ◽

Jie Liu ◽

Anahid Ehteda ◽

...

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Cell Growth ◽

Single Agent ◽

Treatment Strategies ◽

Therapeutic Effects ◽

Loss Of Function ◽

Microtubule Organization

Abstract Diffuse Intrinsic Pontine Glioma (DIPG) are devastating paediatric brainstem tumours. Loss of function mutations in DIPG decrease genetic stability and impair DNA damage response pathways promoting tumourigenesis. Polo-like Kinase 1 (PLK1) is a pivotal controller of cell growth, regulating key intermediaries of DNA replication, homologous repair, the cell cycle and cell division. We have found DIPG cultures consistently overexpress PLK1 with inhibition resulting in decreased tumour cell growth, heightened cell cycle arrest and apoptosis. Single agent treatment using PLK1 inhibitors unprecedentedly doubled the median survival of animals harbouring DIPG tumours. Through gene expression analysis, we’ve showed PLK1 inhibition affected multiple pathways which control the cell cycle, cell death regulation, microtubule organization and regulation of cell migration. We found these pathways of differentially expressed genes were significantly enriched for known targets of both E2F1 and E2F4. Analysis of gene expression and proteomic studies also revealed PLK1 inhibition decreased the activation and expression of key tumour promoting mediators within multiple phases of the cell cycle, decreased expression of tumour promoters including MYC and the PI3K/mTOR pathway and reactivated tumour suppressors p53 and PTEN. Assessing these changes in the treated transcriptome and proteome, we aim to develop multiple potentially translatable combination treatment strategies for DIPG. We have performed mechanistic studies and identified synergism with PLK1 inhibitors and the epigenetic regulator panobinostat, bet/bromodomain inhibitor JQ1, dual PI3K/mTOR inhibitor bimiralisib and PI3K inhibitor BKM120. Finally, we found PLK1 inhibitors act as potent radiosensitizers, enhancing the therapeutic effects of radiotherapy in vitro and in vivo.

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KDM1A and KDM3A promote tumor growth by upregulating cell cycle-associated genes in pancreatic cancer

Experimental Biology and Medicine ◽

10.1177/15353702211023473 ◽

2021 ◽

pp. 153537022110234

Author(s):

Xuyang Hou ◽

Qiuguo Li ◽

Leping Yang ◽

Zhulin Yang ◽

Jun He ◽

...

Keyword(s):

Cell Cycle ◽

Pancreatic Cancer ◽

Tumor Growth ◽

Clinical Stage ◽

Clinical Samples ◽

Loss Of Function ◽

Pancreatic Cancer Cells ◽

A Cell

Pancreatic cancer is a highly malignant cancer of the pancreas with a very poor prognosis. Methylation of histone lysine residues is essential for regulating cancer physiology and pathophysiology, mediated by a set of methyltransferases (KMTs) and demethylases (KDMs). This study surveyed the expression of methylation regulators functioning at lysine 9 of histone 3 (H3K9) in pancreatic lesions and explored the underlying mechanisms. We analyzed KDM1A and KDM3A expression in clinical samples by immunohistochemical staining and searching the TCGA PAAD program and GEO datasets. Next, we identified the variation in tumor growth in vitro and in vivo after knockdown of KDM1A or KDM3A and explored the downstream regulators of KDM1A and KDM3A via RNA-seq, and gain- and loss-of-function assays. Eleven H3K9 methylation regulators were highly expressed in pancreatic cancer, and only KDM1A and KDM3A expression positively correlated with the clinicopathological characteristics in pancreatic cancer. High expression of KDM1A or KDM3A positively correlated with pathological grade, lymphatic metastasis, invasion, and clinical stage. Kaplan–Meier analysis indicated that a higher level of KDM1A or KDM3A led to a shorter survival period. Knockdown of KDM1A or KDM3A led to markedly impaired tumor growth in vitro and in vivo. Mechanistically, CCNA2, a cell cycle-associated gene was partially responsible for KDM1A knockdown-mediated effect and CDK6, also a cell cycle-associated gene was partially responsible for KDM3A knockdown-mediated effect on pancreatic cancer cells. Our study demonstrates that KDM1A and KDM3A are highly expressed in pancreatic cancer and are intimately correlated with clinicopathological factors and prognosis. The mechanism of action of KDM1A or KDM3A was both linked to the regulation of cell cycle-associated genes, such as CCNA2 or CDK6, respectively, by an H3K9-dependent pathway.

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53BP1 and USP28 mediate p53-dependent cell cycle arrest in response to centrosome loss and prolonged mitosis

eLife ◽

10.7554/elife.16270 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 76

Author(s):

Chii Shyang Fong ◽

Gregory Mazo ◽

Tuhin Das ◽

Joshua Goodman ◽

Minhee Kim ◽

...

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Spindle Assembly Checkpoint ◽

Loss Of Function ◽

Interacting Protein ◽

Cycle Arrest ◽

Essential Components ◽

Dependent Cell

Mitosis occurs efficiently, but when it is disturbed or delayed, p53-dependent cell death or senescence is often triggered after mitotic exit. To characterize this process, we conducted CRISPR-mediated loss-of-function screens using a cell-based assay in which mitosis is consistently disturbed by centrosome loss. We identified 53BP1 and USP28 as essential components acting upstream of p53, evoking p21-dependent cell cycle arrest in response not only to centrosome loss, but also to other distinct defects causing prolonged mitosis. Intriguingly, 53BP1 mediates p53 activation independently of its DNA repair activity, but requiring its interacting protein USP28 that can directly deubiquitinate p53 in vitro and ectopically stabilize p53 in vivo. Moreover, 53BP1 can transduce prolonged mitosis to cell cycle arrest independently of the spindle assembly checkpoint (SAC), suggesting that while SAC protects mitotic accuracy by slowing down mitosis, 53BP1 and USP28 function in parallel to select against disturbed or delayed mitosis, promoting mitotic efficiency.

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DIPG-53. CHARACTERIZING THE ROLE OF PPM1D MUTATIONS IN THE PATHOGENESIS OF DIFFUSE INTRINSIC PONTINE GLIOMAS (DIPGS)

Neuro-Oncology ◽

10.1093/neuonc/noaa222.098 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii297-iii297

Author(s):

Prasidda Khadka ◽

Zachary Reitman ◽

Sophie Lu ◽

Graham Buchan ◽

Rachel Hartley ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Radiation Treatment ◽

Ectopic Expression ◽

Loss Of Function ◽

In Vivo Models ◽

Cycle Arrest ◽

Diffuse Intrinsic Pontine Gliomas

Abstract INTRODUCTION We have previously found that up to 15% of all DIPGs harbor mutations in PPM1D, resulting in the expression of an activated and truncated PPM1D (PPM1Dtr). Here we evaluate the mechanisms through which PPM1Dtr enhances glioma formation and identify its associated therapeutic vulnerabilities. METHODS We have developed multiple in vitro and in vivo models of PPM1D-mutant DIPGs and applied quantitative proteomic and functional genomic approaches to identify pathways altered by PPM1Dtr and associated dependencies. RESULTS PPM1D mutations are clonal events that are anti-correlated to TP53 mutations. We find ectopic expression of PPM1Dtr to be sufficient to enhance glioma formation and to be necessary in PPM1D-mutant DIPG cells. In addition, endogenous truncation of PPM1D is sufficient to enhance glioma formation in the presence of mutant H3F3A and PDGFRA. PPM1Dtr overexpression attenuates g-H2AX formation and suppresses apoptosis and cell-cycle arrest in response to radiation treatment. Deep scale phosphoproteomics analyses reveal DNA-damage and cell cycle pathways to be most significantly associated with PPM1Dtr. Furthermore, preliminary analysis of genome-wide loss-of-function CRISPR/Cas9 screens in isogenic GFP and PPM1Dtr overexpressing mouse neural stem cells reveal differential dependency on DNA-damage response genes in the PPM1Dtr overexpressing cells. Consistent with PPM1D’s role in stabilizing MDM2, PPM1D-mutant DIPG models are sensitive to a panel of MDM2 inhibitors (Nutlin-3a, RG7388, and AMG232). CONCLUSION Our study shows that PPM1Dtr is both an oncogene and a dependency in PPM1D- mutant DIPG, and there are novel therapeutic vulnerabilities associated with PPM1D that may be exploited.

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CSIG-16. PATHWAY-BASED APPROACH REVEALS DIFFERENTIAL SENSITIVITY OF GLIOBLASTOMA TO E2F1 INHIBITION

Neuro-Oncology ◽

10.1093/neuonc/noab196.142 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi36-vi36

Author(s):

Alvaro Alvarado ◽

Kaleab Tessema ◽

Sree Muthukrishnan ◽

Riki Kawaguchi ◽

Vivek Swarup ◽

...

Keyword(s):

Cell Cycle ◽

Patient Survival ◽

Enrichment Analysis ◽

Molecular Classification ◽

Gene Set Enrichment Analysis ◽

The Cancer Genome Atlas ◽

Differential Sensitivity ◽

Loss Of Function

Abstract The great phenotypic heterogeneity of glioblastoma (GBM) – both inter and intratumorally – has hindered therapeutic efforts. While genome-based molecular subtyping has revealed that GBMs may be parsed into several molecularly distinct categories, this insight has not translated to a significant extension of patient survival. We hypothesize that, rather than gene expression as a whole, analysis of targetable pathways could yield important insights into the development of novel classification schemes and, most importantly, to targeted therapeutics. Here, we interrogated tumor samples using a pathway-based approach to resolve tumoral heterogeneity. The Cancer Genome Atlas samples were clustered using gene set enrichment analysis and the resulting 3 clusters were informative of patient survival and only modestly overlapped with prior molecular classification. We validated our approach by generating gene lists from common elements found in the top contributing genesets for a particular cluster and testing the top targets in appropriate gliomasphere patient-derived lines. Samples enriched for cell cycle related genesets showed a decrease in sphere formation capacity, proliferation and in vivo tumor growth when E2F1, our top target, was silenced. Consistent with our theory, E2F1 knockdown had little or no effect on the growth of the non-enriched lines, despite their ability to proliferate in vitro and in vivo. We similarly analyzed single cell RNAseq datasets and correlated cell cycle and stemness signatures with the gene lists we generated as well as with molecular states and cell specific signatures. Finally, we confirmed a connection between E2F1 and cellular inhibitor of PP2A (CIP2A) in a cluster of samples. Loss of function studies reveals a diminished capacity for DNA damage regulation in E2F1 activated samples. Our studies relate inter- and intratumoral heterogeneity to critical cellular pathways dysregulated in GBM, with the ultimate goal of establishing a pipeline for patient- and tumor-specific precision medicine.

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