scholarly journals Over-expression of Plk4 induces centrosome amplification, loss of primary cilia and associated tissue hyperplasia in the mouse

Open Biology ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 150209 ◽  
Author(s):  
Paula A. Coelho ◽  
Leah Bury ◽  
Marta N. Shahbazi ◽  
Kifayathullah Liakath-Ali ◽  
Peri H. Tate ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Primary Cultures ◽  
Centrosome Amplification ◽  
Proliferating Cells ◽  
Differentiation Markers ◽  
Over Expression ◽  
Centriole Duplication ◽  
Keratin 5 ◽  
Tumour Formation ◽  
Tumour Suppressor P53

To address the long-known relationship between supernumerary centrosomes and cancer, we have generated a transgenic mouse that permits inducible expression of the master regulator of centriole duplication, Polo-like-kinase-4 (Plk4). Over-expression of Plk4 from this transgene advances the onset of tumour formation that occurs in the absence of the tumour suppressor p53. Plk4 over-expression also leads to hyperproliferation of cells in the pancreas and skin that is enhanced in a p53 null background. Pancreatic islets become enlarged following Plk4 over-expression as a result of equal expansion of α- and β-cells, which exhibit centrosome amplification. Mice overexpressing Plk4 develop grey hair due to a loss of differentiated melanocytes and bald patches of skin associated with a thickening of the epidermis. This reflects an increase in proliferating cells expressing keratin 5 in the basal epidermal layer and the expansion of these cells into suprabasal layers. Such cells also express keratin 6, a marker for hyperplasia. This is paralleled by a decreased expression of later differentiation markers, involucrin, filaggrin and loricrin. Proliferating cells showed an increase in centrosome number and a loss of primary cilia, events that were mirrored in primary cultures of keratinocytes established from these animals. We discuss how repeated duplication of centrioles appears to prevent the formation of basal bodies leading to loss of primary cilia, disruption of signalling and thereby aberrant differentiation of cells within the epidermis. The absence of p53 permits cells with increased centrosomes to continue dividing, thus setting up a neoplastic state of error prone mitoses, a prerequisite for cancer development.

scholarly journals Ano1 as a regulator of proliferation

2011 ◽  
Vol 301 (6) ◽  
pp. G1044-G1051 ◽  
Author(s):  
Jennifer E. Stanich ◽  
Simon J. Gibbons ◽  
Seth T. Eisenman ◽  
Michael R. Bardsley ◽  
Jason R. Rock ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Slow Wave ◽  
Interstitial Cells Of Cajal ◽  
Primary Cultures ◽  
Channel Blockers ◽  
Proliferating Cells ◽  
Stromal Tumors ◽  
Whole Mount ◽  
Cells Of Cajal ◽  
Regular Medium

Ano1 is a recently discovered Ca2+-activated Cl− channel expressed on interstitial cells of Cajal (ICC) that has been implicated in slow-wave activity in the gut. However, Ano1 is expressed on all classes of ICC, even those that do not contribute to generation of the slow wave, suggesting that Ano1 may have an alternate function in these cells. Ano1 is also highly expressed in gastrointestinal stromal tumors. Mice lacking Ano1 had fewer proliferating ICC in whole mount preparations and in culture, raising the possibility that Ano1 is involved in proliferation. Cl− channel blockers decreased proliferation in cells expressing Ano1, including primary cultures of ICC and in the pancreatic cancer-derived cell line, CFPAC-1. Cl− channel blockers had a reduced effect on Ano1(−/−) cultures, confirming that the blockers are acting on Ano1. Ki67 immunoreactivity, 5-ethynyl-2′-deoxyuridine incorporation, and cell-cycle analysis of cells grown in low-Cl− media showed fewer proliferating cells than in cultures grown in regular medium. We confirmed that mice lacking Ano1 had less phosphorylated retinoblastoma protein compared with controls. These data led us to conclude that Ano1 regulates proliferation at the G1/S transition of the cell cycle and may play a role in tumorigenesis.

Type I platelet-activating factor acetylhydrolase catalytic subunits over-expression induces pleiomorphic nuclei and centrosome amplification

2007 ◽  
Vol 12 (10) ◽  
pp. 1153-1161 ◽  
Author(s):  
Noritaka Yamaguchi ◽  
Hiroyuki Koizumi ◽  
Junken Aoki ◽  
Yumiko Natori ◽  
Kiyotaka Nishikawa ◽  
...  
Keyword(s):  
Platelet Activating Factor ◽  
Centrosome Amplification ◽  
Type I ◽  
Catalytic Subunits ◽  
Over Expression ◽  
Platelet Activating Factor Acetylhydrolase

Abstract 052: Epicardial-derived Adrenomedullin Drives Cardiac Hyperplasia During Embryogenesis

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Sarah E Wetzel-Strong ◽  
Manyu Li ◽  
Toshio Nishikimi ◽  
Kathleen M Caron
Keyword(s):  
Embryonic Development ◽  
Heart Development ◽  
Cardiac Development ◽  
Lymphatic Vessels ◽  
Heart Weight ◽  
Cardiovascular Development ◽  
Proliferating Cells ◽  
Over Expression ◽  
Knockout Animals

The multi-functional peptide adrenomedullin ( Adm = gene, AM = protein) plays important roles in embryonic development and disease. Previous studies demonstrated that Adm knockout mice die at embryonic day 13.5 with small, disorganized hearts and hypoplastic lymphatic vessels, highlighting the importance of this peptide in normal cardiovascular development. Since Adm knockout animals are embryonic lethal, our goal was to generate and characterize a novel model of Adm over-expression to study the role of Adm during development and disease processes. Through gene targeting techniques, we generated a novel mouse model of Adm over-expression, abbreviated as Adm hi/hi . When we assessed gene expression of Adm from 10 different tissues, we found Adm hi/hi mice express 3- to 15-fold more Adm than wildtype littermates. Additionally, peptide levels of AM in lung and kidney, as well as circulating plasma levels of AM were elevated 3-fold over wildtype mice, indicating a functional increase in AM. Our initial analysis revealed that adult Adm hi/hi mice have larger heart weight to body weight ratios than wildtype littermates (4.93±0.23 vs. 5.96±0.29, n = 11-12). We found that compared to wildtype, Adm hi/hi embryos have more proliferating cells during heart development (14.46±1.11 vs. 31.97±2.84, n=4), indicating that hyperplasia drives Adm hi/hi heart enlargement. By crossing the Adm hi/hi line to different tissue-specific Cre lines, we were able to excise the stabilizing bovine growth hormone 3’UTR, thereby returning Adm expression levels back to wildtype in cells with active Cre recombinase. Using this approach, we identified the epicardium as a major source of AM during cardiac development. In conclusion, we found that AM derived primarily from the epicardium drives cardiac hyperplasia during embryonic development resulting in persistent, enlarged hearts of adult Adm hi/hi mice. Since our Adm hi/hi mice recapitulate the 3-fold plasma elevation of AM observed during human disease, this mouse line will be a useful tool for studying the role of elevated AM during disease.

SKA1 over-expression promotes centriole over-duplication, centrosome amplification and prostate tumourigenesis

2014 ◽  
Vol 234 (2) ◽  
pp. 178-189 ◽  
Author(s):  
Jia Li ◽  
Jim W Xuan ◽  
Vida Khatamianfar ◽  
Fatma Valiyeva ◽  
Madeleine Moussa ◽  
...  
Keyword(s):  
Centrosome Amplification ◽  
Over Expression

scholarly journals Alterations of the Hsp70/Hsp90 chaperone and the HOP/CHIP co-chaperone system in cancer

2012 ◽  
Vol 17 (3) ◽  
Author(s):  
Eva Ruckova ◽  
Petr Muller ◽  
Rudolf Nenutil ◽  
Borivoj Vojtesek
Keyword(s):  
Colorectal Cancer ◽  
Cancer Cells ◽  
Binding Sites ◽  
Patient Survival ◽  
Proliferating Cells ◽  
Response Elements ◽  
Over Expression ◽  
Hsp90 Activity ◽  
Hsp90 Chaperone ◽  
Client Proteins

AbstractActivation of the Hsp90 chaperone system is a characteristic of cancer cells. The regulation of chaperone activities involves their interaction with cochaperones; therefore we investigated the expression of Hsp70 and Hsp90 and their specific co-chaperones HOP and CHIP in cancer cell lines and primary cancers. Inhibition of Hsp90 by 17AAG increased the levels of Hsp70, Hsp90 and HOP but not CHIP mRNA in cancer cells. These changes are linked to activation of the HSF1 transcription factor and we show that the HOP promoter contains HSF1 binding sites, and that HSF1 binding to the HOP promoter is increased following 17AAG. The lack of alteration in the co-chaperone CHIP is explained by a lack of HSF response elements in the CHIP promoter. Non-proliferating cells expressed higher levels of CHIP and lower HOP, Hsp70 and Hsp90 levels compared to proliferating cells. Decreased expression of CHIP in proliferating cancer cells is in keeping with its proposed tumor suppressor properties, while over-expression of HOP in proliferating cells may contribute to excessive Hsp90 activity and stabilization of client proteins in tumors. In a panel of colorectal cancer samples, increased expression of Hsp70 and an increased ratio of HOP to CHIP were found, and were associated with decreased median survival. These data indicate that multiple changes occur in the chaperone/co-chaperone system in cancer that impact patient survival. It is likely that the ability to identify individual alterations to this system will be beneficial for treatment strategy decisions, particularly those that employ chaperone inhibitors.

scholarly journals C3G (RapGEF1) localizes to the mother centriole and regulates centriole division and primary cilia dynamics

2019 ◽  
Author(s):  
Sanjeev Chavan Nayak ◽  
Vegesna Radha
Keyword(s):  
Embryonic Development ◽  
Primary Cilia ◽  
Negative Regulator ◽  
Ciliated Cells ◽  
Wild Type ◽  
Centrosomal Protein ◽  
Over Expression ◽  
Cilia Formation ◽  
Mother Centriole ◽  
Summary Statement

AbstractC3G (RapGEF1), a negative regulator of β-catenin, plays a role in cell differentiation and is essential for early embryonic development in mice. In this study, we identify C3G as a centrosomal protein that regulates centriole division and primary cilia dynamics. C3G is present at the centrosome in interphase as well as mitotic cells, but is absent at the centrioles in differentiated myotubes. It interacts with, and co-localizes with cenexin in the mother centriole. Stable clone of cells depleted of C3G by CRISPR/Cas9 showed reduction in cenexin protein, and presence of supernumerary centrioles. Over-expression of C3G resulted in inhibition of centrosome division in normal and hydroxyurea treated cells. Proportion of ciliated cells is higher, and cilia length longer in C3G knockout cells. C3G inhibits cilia formation and length dependent on its catalytic activity. Unlike wild type cells, C3G depleted cells inefficiently retracted their cilia upon stimulation to reenter the cell cycle, and proliferated slowly, arresting in G1. We conclude that C3G inhibits centriole division and maintains ciliary homeostasis, properties that may be important for its role in embryonic development.Summary statementWe identify C3G as a centrosomal protein and regulator of centriole number, primary cilia length and resorption. These properties are important for its role in embryogenesis, and suggest that mutations in C3G could cause ciliopathies.

scholarly journals PLK4 promotes centriole duplication by phosphorylating STIL to link the procentriole cartwheel to the microtubule wall

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Tyler Chistopher Moyer ◽  
Andrew Jon Holland
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Primary Cilia ◽  
Significant Progress ◽  
Binding Interaction ◽  
Limited Knowledge ◽  
Centriole Duplication ◽  
Made In ◽  
Stable Incorporation

Centrioles play critical roles in organizing the assembly of the mitotic spindle and templating the formation of primary cilia. Centriole duplication occurs once per cell cycle and is regulated by Polo-like kinase 4 (PLK4). Although significant progress has been made in understanding centriole composition, we have limited knowledge of how PLK4 activity controls specific steps in centriole formation. Here, we show that PLK4 phosphorylates its centriole substrate STIL on a conserved site, S428, to promote STIL binding to CPAP. This phospho-dependent binding interaction is conserved in Drosophila and facilitates the stable incorporation of both STIL and CPAP into the centriole. We propose that procentriole assembly requires PLK4 to phosphorylate STIL in two different regions: phosphorylation of residues in the STAN motif allow STIL to bind SAS6 and initiate cartwheel assembly, while phosphorylation of S428 promotes the binding of STIL to CPAP, linking the cartwheel to microtubules of the centriole wall.

Loss of p27Kip1 function results in increased proliferative capacity of oligodendrocyte progenitors but unaltered timing of differentiation

Development ◽  
1999 ◽  
Vol 126 (18) ◽  
pp. 4027-4037 ◽  
Author(s):  
P. Casaccia-Bonnefil ◽  
R.J. Hardy ◽  
K.K. Teng ◽  
J.M. Levine ◽  
A. Koff ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Myelin Basic Protein ◽  
Basic Protein ◽  
Growth Arrest ◽  
Proliferating Cells ◽  
Differentiation Markers ◽  
Oligodendrocyte Progenitors ◽  
Cell Divisions ◽  
Glial Progenitors

In many tissues, progenitor cells permanently withdraw from the cell cycle prior to commitment towards a differentiated phenotype. In the oligodendrocyte lineage a counting mechanism has been proposed, linking the number of cell divisions to growth arrest and differentiation. A direct prediction of this model is that an increase in the number of cell divisions would result in a delayed onset of differentiation. Since the cell cycle inhibitor p27Kip1 is an essential component of the machinery leading to oligodendrocyte progenitor growth arrest, we examined the temporal relationship between cell cycle withdrawal and expression of late differentiation markers in vivo, in mice carrying a targeted deletion in the p27Kip1 gene. Using bromodeoxyuridine to label proliferating cells, quaking (QKI) to identify embryonic glial progenitors, NG2 to identify neonatal oligodendrocyte progenitors, and myelin basic protein to label differentiated oligodendrocytes, we found an increased number of proliferating QKI- and NG2-positive cells in germinal zones of p27Kip1(−/−) mice at the peak of gliogenesis. However, no delay was observed in these mice in the appearance of the late differentiation marker myelin basic protein in the developing corpus callosum and cerebellum. Significantly, a decrease in cyclin E levels was observed in the brain of p27Kip1 null mice coincident with oligodendrocyte growth arrest. We conclude that two distinct modalities of growth arrest occur in the oligodendrocyte lineage: a p27Kip1-dependent mechanism of growth arrest affecting proliferation in early phases of gliogenesis, and a p27Kip1-independent event leading to withdrawal from the cell cycle and differentiation.

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