Related Experiment Video

Updated: Aug 13, 2026

Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors
10:33

Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors

Published on: October 26, 2015

Protein kinase C delta inhibits Caco-2 cell proliferation by selective changes in cell cycle and cell death

S R Cerda1, R Mustafi, H Little

  • 1Department of Medicine, Division of Gastroenterology, University of Chicago, Chicago, IL 60637, USA. scerda@medicine.bsd.uchicago.edu

Oncogene
|January 26, 2006
PubMed

Insights

Protein kinase C-delta (PKC-delta) inhibits colon cancer cell growth by slowing cell cycle progression and promoting apoptosis. This study elucidates PKC-delta

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Oncology

Background:

  • Protein kinase C-delta (PKC-delta) is a serine/threonine kinase involved in various signaling pathways.
  • Previous studies indicated PKC-delta overexpression slows G1 progression, accelerates apoptosis, and induces differentiation in Caco-2 colon cancer cells.

Purpose of the Study:

  • To further characterize the specific signaling pathways by which PKC-delta exerts its tumor suppressor functions in Caco-2 colon cancer cells.
  • To investigate the role of PKC-delta in regulating cell cycle progression and apoptosis.

Main Methods:

  • Utilized a Zn2+ inducible expression vector to overexpress PKC-delta in Caco-2 cells.
  • Employed Western blotting, quantitative PCR, and co-immunoprecipitation to analyze protein and mRNA levels of cyclins, cyclin-dependent kinase (cdk) inhibitors, and apoptosis regulators.
  • Used small interfering RNA (siRNA) to specifically knock down PKC-delta expression and assess its effects on cell proliferation and apoptosis.

Main Results:

  • PKC-delta overexpression significantly downregulated cyclin D1 and cyclin E protein levels, leading to G1 cell cycle arrest.
  • PKC-delta upregulated the expression of p21(Waf1), a cdk inhibitor, and increased the binding of p27(Kip1) to cdk4, further inhibiting G1 kinase activity.
  • Knockdown of PKC-delta using siRNA enhanced cell proliferation and increased cyclin D1 and cyclin E expression, confirming its antiproliferative role.
  • PKC-delta overexpression increased the pro-apoptotic regulator Bax and decreased the anti-apoptotic protein Bcl-2, promoting apoptosis.
  • PKC-delta knockdown inhibited Bax protein expression, indicating its role in regulating apoptosis.

Conclusions:

  • PKC-delta inhibits colon cancer cell proliferation by suppressing G1 cell cycle progression through modulation of cyclin/cdk complexes and their inhibitors.
  • PKC-delta promotes apoptosis in colon cancer cells by regulating the expression of Bax and Bcl-2.
  • These findings elucidate critical antiproliferative mechanisms mediated by PKC-delta, highlighting its significant tumor suppressor function in colon carcinogenesis.

More Related Videos

Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes15:43

Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes

Published on: January 7, 2013

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

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...
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.
Positive Regulator Molecules01:45

Positive Regulator Molecules

To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
Molecular Factors Affecting Cell Division01:27

Molecular Factors Affecting Cell Division

Several external and internal factors influence the initiation and inhibition of cell division. For instance, the death of nearby cells or the release of human growth hormone (hGH) promotes cell division. In contrast, lack of hGH or crowding of cells can inhibit cell division.
Several proteins function as internal regulators to ensure each cell cycle stage is completed faithfully before proceeding to the next. Regulator molecules may act directly or influence the activity or production of other...