Related Experiment Video

Updated: Jul 31, 2026

Through the Looking Glass: Time-lapse Microscopy and Longitudinal Tracking of Single Cells to Study Anti-cancer Therapeutics
06:00

Through the Looking Glass: Time-lapse Microscopy and Longitudinal Tracking of Single Cells to Study Anti-cancer Therapeutics

Published on: May 14, 2016

P16Ink4a tumor suppressor function in lung cancer cells involves cyclin-dependent kinase 2 inhibition by Cip/Kip

B Grimison1, T A Langan, R A Sclafani

  • 1University of Colorado Comprehensive Cancer Center and Department of Biochemistry and Molecular Genetics, Denver 80262, USA.

Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research
|November 4, 2000
PubMed

Insights

Targeting cyclin-dependent kinases (cdks) offers a new cancer therapy. Inhibiting cdks, like cdk4/cdk6, can suppress non-small cell lung cancer (NSCLC) growth by restoring cell cycle control.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Cyclin-dependent kinases (cdks) regulate the cell cycle and are frequently dysregulated in human cancers.
  • Non-small cell lung carcinomas (NSCLCs) often exhibit inappropriate cdk activity despite expressing functional retinoblastoma protein (Rb).
  • Inactivation of the p16Ink4a cdk inhibitor contributes to elevated cdk4/cdk6 activity in NSCLC cells.

Purpose of the Study:

  • To model the effects of cdk4/cdk6 inhibition in a relevant NSCLC context.
  • To investigate the role of p16Ink4a re-expression in Rb-positive NSCLC cells.
  • To understand the downstream effects of p16Ink4a on other cdks and cell growth.

Main Methods:

  • Expression of p16Ink4a in a Rb-positive NSCLC cell line lacking endogenous p16Ink4a.
  • Analysis of cdk activity, including cdk4/cdk6 and cdk2.
  • Assessment of retinoblastoma protein (Rb) phosphorylation status.
  • Evaluation of cell growth suppression.

Main Results:

  • p16Ink4a expression led to expected cdk4/cdk6 inhibition and Rb dephosphorylation.
  • An unexpected, indirect inhibition of cdk2 was observed.
  • cdk2 inactivation may involve the redistribution of other cdk inhibitors.
  • p16Ink4a expression resulted in growth suppression of Rb-positive NSCLC cells.

Conclusions:

  • Re-expression of p16Ink4a effectively inhibits cdk4/cdk6 and suppresses NSCLC cell growth.
  • Indirect cdk2 inhibition is a significant consequence of p16Ink4a expression in this model.
  • cdk2 inactivation might be crucial for p16Ink4a-mediated growth suppression in Rb-positive cells.
  • These findings have implications for the clinical use of chemical cdk inhibitors in cancer therapy.

More Related Videos

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer06:51

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer

Published on: July 21, 2018

Analysis of Combinatorial miRNA Treatments to Regulate Cell Cycle and Angiogenesis11:44

Analysis of Combinatorial miRNA Treatments to Regulate Cell Cycle and Angiogenesis

Published on: March 30, 2019

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...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
Loss of Tumor Suppressor Gene Functions01:12

Loss of Tumor Suppressor Gene Functions

Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
Cancer-Critical Genes II: Tumor Suppressor Genes01:05

Cancer-Critical Genes II: Tumor Suppressor Genes

Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, thereby altering the phenotype.
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
The Retinoblastoma Gene01:20

The Retinoblastoma Gene

Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
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...