Related Experiment Video

Updated: Aug 17, 2026

Senescence Detection Using Reflected Light in Adipose Stromal Vascular Fraction
10:08

Senescence Detection Using Reflected Light in Adipose Stromal Vascular Fraction

Published on: June 5, 2026

CDK2 translational down-regulation during endothelial senescence

Deborah A Freedman1, Judah Folkman

  • 1Vascular Biology Program, Department of Surgery, Children's Hospital, 1 Blackfan Circle, Harvard University Medical School, Karp Family Research Laboratories, Floor 12, Boston, MA 02115, USA.

Experimental Cell Research
|June 1, 2005
PubMed

Insights

Loss of CDK2 activity, due to translational decline and p21 inhibition, drives endothelial cell senescence. Telomerase bypasses senescence by restoring CDK2 translation and activity, revealing a key regulatory mechanism.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Gerontology

Background:

  • Endothelial cell senescence limits cellular lifespan and impacts tissue function.
  • Cyclin-dependent kinase 2 (CDK2) activity is crucial for cell cycle progression.

Purpose of the Study:

  • To investigate the role of CDK2 activity and its regulators in endothelial cell senescence.
  • To explore mechanisms by which endothelial cells bypass senescence.

Main Methods:

  • Utilized dominant-negative p53 expression and telomerase introduction in human umbilical vein endothelial cells (HUVECs).
  • Analyzed expression of cell-cycle inhibitors (p16INK4a, p21Cip1/Waf1) and CDK2 protein levels and activity.
  • Assessed CDK2 translation rates and protein stability during senescence and immortalization.

Main Results:

  • Loss of CDK2 activity, via translational inhibition and p21Cip1/Waf1, is linked to endothelial senescence.
  • Telomerase expression in HUVECs leads to immortalization (i-HUVECs) by restoring CDK2 translation and activity.
  • Senescent HUVECs exhibit undetectable CDK2 activity due to reduced protein levels and p21 inhibition; p16INK4a expression persists.

Conclusions:

  • CDK2 translational down-regulation is a key event in endothelial replicative senescence.
  • p16INK4a does not appear to play a significant role in endothelial senescence.
  • Understanding endothelial senescence mechanisms is vital for cancer research.

More Related Videos

Induction and Validation of Cellular Senescence in Primary Human Cells08:18

Induction and Validation of Cellular Senescence in Primary Human Cells

Published on: June 20, 2018

Murine Dermal Lymphatic Endothelial Cell Isolation05:52

Murine Dermal Lymphatic Endothelial Cell Isolation

Published on: July 21, 2023

Related Concept Videos

Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
Inhibition of CDK Activity02:34

Inhibition of CDK Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
M-Cdk Drives Transition Into Mitosis02:15

M-Cdk Drives Transition Into Mitosis

Checkpoints throughout the cell cycle serve as safeguards and gatekeepers, allowing the cell cycle to progress in favorable conditions and slow or halt it in problematic ones. This regulation is known as the cell cycle control system.
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
Regulation of Angiogenesis and Blood Supply01:24

Regulation of Angiogenesis and Blood Supply

Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits.  Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...