Death in the Life of a Tooth

2004 ◽  
Vol 83 (1) ◽  
pp. 11-16 ◽  
Author(s):  
E. Matalova ◽  
A.S. Tucker ◽  
P.T. Sharpe
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Cell Division ◽  
Programmed Cell Death ◽  
Tooth Development ◽  
Cell Number ◽  
Substantial Evidence ◽  
Bud Formation ◽  
Dental Lamina ◽  
Tooth Buds

Programmed cell death (apoptosis) constitutes an important mechanism in embryonic development. Although there is substantial evidence for essential roles of apoptosis in organ shaping and controlling of cell number, the mechanisms of these processes are poorly understood. The regulation of cell proliferation to form tooth buds of the appropriate size and at the correct positions must involve a balance between cell division and cell death. Apoptosis has been suggested to play both passive and active roles in bud formation and morphogenesis and in reduction of the dental lamina, as well as silencing of the enamel knot signaling centers. The location of apoptotic cells during tooth development has been described and suggests their temporospatial roles. Unfortunately, there is little functional evidence on these roles, and the aim of this review is to highlight areas where apoptosis may play key roles in odontogenesis.

Genomic components of carcinogenesis

1993 ◽  
Vol 39 (11) ◽  
pp. 2375-2385 ◽  
Author(s):  
R Schmandt ◽  
G B Mills
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Death ◽  
Growth Factors ◽  
Cell Division ◽  
Programmed Cell Death ◽  
Tumor Cells ◽  
Tumor Suppressor Genes ◽  
Normal Cells ◽  
Biochemical Pathways

Abstract Many of the genes encoding growth factors, growth factor receptors, enzymes, and other effector molecules that regulate normal cell growth are designated protooncogenes. Oncogenes, those genes associated with cellular transformation, differ from their protooncogenic progenitors by being mutated, overexpressed, or expressed at inappropriate times or locations in the cell. One of the activities of growth factors is to prime cells to undergo programmed cell death, which is characterized by a series of morphologic changes called apoptosis. In normal cells, specific mediators must be activated or suppressed to bypass programmed cell death. In tumor cells, either the pathways leading to apoptosis are not functional or the mediators that normally "rescue" cells from this fate are overexpressed or constitutively activated. In addition to the biochemical pathways that drive cell division, there are others that limit cell proliferation; these, designated tumor suppressors, anti-oncogenes, or recessive oncogenes, must be inactivated in normal cells to allow passage through the cell cycle and cell proliferation. In contrast to oncogenes, which are overexpressed or activated in tumors, tumor-suppressor genes are frequently inactivated in tumor cells, either by mutation or deletion. Thus, in normal cells a series of checks and balances must be overcome to allow initiation and continuation of cell division. In tumors, these processes are aberrant, resulting in increased rates of cell division, increases in the proportion of cells in the cell cycle, or increased survival of activated cells. Therefore, tumor cells frequently accumulate genomic alterations, which may result in the activation of a particular array of oncogenes, the inactivation of specific tumor-suppressor genes, and the bypassing of programmed cell death. Trials of antitumor agents that act by exploiting the overexpression of oncogenes in tumors and of the biochemical pathways by which they mediate cell proliferation are currently underway.

scholarly journals Many Genomic Regions Are Required for Normal Embryonic Programmed Cell Death in Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 237-252
Author(s):  
Asako Sugimoto ◽  
Ayumi Kusano ◽  
Rebecca R Hozak ◽  
W Brent Derry ◽  
Jiangwen Zhu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Programmed Cell Death ◽  
Embryonic Cell ◽  
Direct Result ◽  
Class Iii ◽  
Cell Corpse ◽  
Genomic Regions

Abstract To identify genes involved in programmed cell death (PCD) in Caenorhabditis elegans, we screened a comprehensive set of chromosomal deficiencies for alterations in the pattern of PCD throughout embryonic development. From a set of 58 deficiencies, which collectively remove ∼74% of the genome, four distinct classes were identified. In class I (20 deficiencies), no significant deviation from wild type in the temporal pattern of cell corpses was observed, indicating that much of the genome does not contain zygotic genes that perform conspicuous roles in embryonic PCD. The class II deficiencies (16 deficiencies defining at least 11 distinct genomic regions) led to no or fewer-than-normal cell corpses. Some of these cause premature cell division arrest, probably explaining the diminution in cell corpse number; however, others have little effect on cell proliferation, indicating that the reduced cell corpse number is not a direct result of premature embryonic arrest. In class III (18 deficiencies defining at least 16 unique regions), an excess of cell corpses was observed. The developmental stage at which the extra corpses were observed varied among the class III deficiencies, suggesting the existence of genes that perform temporal-specific functions in PCD. The four deficiencies in class IV (defining at least three unique regions), showed unusually large corpses that were, in some cases, attributable to extremely premature arrest in cell division without a concomitant block in PCD. Deficiencies in this last class suggest that the cell death program does not require normal embryonic cell proliferation to be activated and suggest that while some genes required for cell division might also be required for cell death, others are not. Most of the regions identified by these deficiencies do not contain previously identified zygotic cell death genes. There are, therefore, a substantial number of as yet unidentified genes required for normal PCD in C. elegans.

scholarly journals Receptor Tyrosine Kinases: Role in Cancer Progression

2006 ◽  
Vol 13 (5) ◽  
pp. 191-193
Author(s):  
V. Sangwan ◽  
M. Park
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Cancer Progression ◽  
Tyrosine Kinases ◽  
Normal Tissue ◽  
Receptor Tyrosine Kinases ◽  
Tight Control ◽  
Tissue Patterning

Tight control of cell proliferation and morphogenesis in conjunction with programmed cell death (apoptosis) is required to ensure normal tissue patterning. [...]

Suppression of cell proliferation and programmed cell death by dexamethasone during postnatal lung development

2002 ◽  
Vol 282 (3) ◽  
pp. L477-L483 ◽  
Author(s):  
Cédric Luyet ◽  
Peter H. Burri ◽  
Johannes C. Schittny
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Lung Development ◽  
Structural Changes ◽  
Tissue Transglutaminase ◽  
Lung Parenchyma ◽  
Lung Maturation ◽  
Morphological Criteria ◽  
Postnatal Lung Development

Prematurely born babies are often treated with glucocorticoids. We studied the consequences of an early postnatal and short dexamethasone treatment (0.1–0.01 μg/g, days 1–4) on lung development in rats, focusing on its influence on peaks of cell proliferation around day 4 and of programmed cell death at days 19–21. By morphological criteria, we observed a dexamethasone-induced premature maturation of the septa ( day 4), followed by a transient septal immatureness and delayed alveolarization leading to complete rescue of the structural changes. The numbers of proliferating (anti-Ki67) and dying cells (TdT-mediated dUTP nick end labeling) were determined and compared with controls. In dexamethasone-treated animals, both the peak of cell proliferation and the peak of programmed cell death were reduced to baseline, whereas the expression of tissue transglutaminase (transglutaminase-C), another marker for postnatal lung maturation, was not significantly altered. We hypothesize that a short neonatal course of dexamethasone leads to severe but transient structural changes of the lung parenchyma and influences the balance between cell proliferation and cell death even in later stages of lung maturation.

scholarly journals miR-103 Functions as a Tumor Suppressor by Directly Targeting Programmed Cell Death 10 in NSCLC

2018 ◽  
Vol 26 (4) ◽  
pp. 519-528 ◽  
Author(s):  
Dong Yang ◽  
Jian-Jun Wang ◽  
Jin-Song Li ◽  
Qian-Yu Xu
Keyword(s):  
Lung Cancer ◽  
Cell Proliferation ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Tumor Size ◽  
Apoptotic Cell ◽  
A549 Cells ◽  
Invasion And Migration ◽  
Metastatic Capacity ◽  
And Migration

Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancer cases. Absence of miR-103 has recently been identified to be associated with metastatic capacity of primary lung tumors. However, the exact role of miR-103 in NSCLC and the molecular mechanism are unclear. In the present study, we showed that miR-103 expression was reduced in NSCLC tissues and cells. miR-103 expression was negatively correlated with tumor size and stage. The overall survival was longer in patients with higher miR-103 level than in those with lower miR-103 expression. miR-103 inhibited cell proliferation in A549 cells, decreased tumor weight and volume, and prolonged survival of tumor-implanted nude mice. miR-103 increased apoptotic cell death in A549 cells. Furthermore, miR-103 decreased the invasion and migration abilities in A549 cells, as evidenced by Transwell and wound healing results. Downregulation of miR-103 significantly reduced the level of programmed cell death 10 (PDCD10). We found a significant decrease in the relative luciferase activity of the reporter gene in A549 cells cotransfected with the miR-103 mimic and pGL3-PDCD10 WT 3′-UTR, but not pGL3-PDCD10 mut 3′-UTR. We showed that overexpression of PDCD10 significantly inhibited miR-103-induced inhibition of cell proliferation, increased apoptosis, and decreased invasion and migration in A549 cells. Moreover, we found that PDCD10 expression was increased in NSCLC tissues and cells. PDCD10 expression was positively correlated with tumor size and stage. Overexpression of PDCD10 increased cell proliferation and inhibited apoptosis in A549 cells. The data demonstrated that dysregulation of the miR-103/PDCD10 signal may be a novel therapeutic target for the treatment of NSCLC.

scholarly journals Evaluating the Remote Control of Programmed Cell Death, with or without a Compensatory Cell Proliferation

2018 ◽  
Vol 14 (13) ◽  
pp. 1800-1812 ◽  
Author(s):  
Xixi Dou ◽  
Lichan Chen ◽  
Mingjuan Lei ◽  
Lucas Zellmer ◽  
Qingwen Jia ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Remote Control ◽  
Programmed Cell Death

Reduction of the rate of outgrowth, cell density, and cell division following removal of the apical ectodermal ridge of the chick limb-bud

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 1-21
Author(s):  
Dennis Summerbell
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Cell Division ◽  
Cell Density ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Short Term ◽  
Density Dependent ◽  
Wing Bud

Removal of the apical ectodermal ridge causes a reduction in the rate of outgrowth of the wing-bud and the loss of distal parts. More specifically it causes a short-term increase in cell density and cell death and a decrease in the rate of cell proliferation. The evidence supports the hypothesis of density-dependent control of cell division and suggests that there may also be a mechanism regulating skeletal length at the time of differentiation. An informal model is presented to explain the observations.

scholarly journals Planarian cell number depends on blitzschnell, a novel gene family that balances cell proliferation and cell death

Development ◽  
2020 ◽  
Vol 147 (7) ◽  
pp. dev184044 ◽  
Author(s):  
Eudald Pascual-Carreras ◽  
Marta Marin-Barba ◽  
Carlos Herrera-Úbeda ◽  
Daniel Font-Martín ◽  
Kay Eckelt ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Gene Family ◽  
Cell Number ◽  
Novel Gene
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