Related Experiment Video

Updated: Jul 15, 2026

Proliferation and Differentiation of Murine Myeloid Precursor 32D/G-CSF-R Cells
10:21

Proliferation and Differentiation of Murine Myeloid Precursor 32D/G-CSF-R Cells

Published on: February 21, 2018

TGFbeta regulates the expression and activities of G2 checkpoint kinases in human myeloid leukemia cells

Xiaotang Hu1, Dongming Cui, Lynn C Moscinski

  • 1Interdisciplinary Oncology Program, University of South Florida, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33161, USA. xthu@mail.barry.edu

Cytokine
|April 27, 2007
PubMed

Insights

Transforming Growth Factor-beta (TGFbeta) directly inhibits G2 checkpoint kinases, downregulating key proteins like cdc2 and cyclin B1 at the mRNA level in leukemia cells. This action amplifies TGFbeta-induced growth inhibition.

Area of Science:

  • Cell cycle regulation
  • Molecular biology
  • Cancer research

Background:

  • Transforming Growth Factor-beta (TGFbeta) is a known inhibitor of G1 cyclin/cdk activity.
  • The effect of TGFbeta on G2 checkpoint kinases is not well understood.

Purpose of the Study:

  • To investigate the impact of TGFbeta on G2 checkpoint kinases in human leukemia cell lines.
  • To determine the mechanism and consequences of TGFbeta's effect on G2 checkpoint regulation.

Main Methods:

  • Analysis of G2 checkpoint kinase expression (cdc2, cyclin B1, cdc25c) via mRNA levels.
  • Time-dependent inhibition studies.
  • Assessment of cdc2-pRb complex formation.
  • In vitro kinase assays using GST-Rb protein.
  • Examination of cdc2 (Tyr15) and cdc25c (Ser216) phosphorylation status.

Main Results:

  • TGFbeta downregulated cdc2, cyclin B1, and cdc25c expression at the mRNA level in a time-dependent manner.
  • Inhibition occurred without G2/M phase cell accumulation, indicating a direct effect.
  • TGFbeta treatment reduced cdc2-pRb complex formation and cdc2 kinase activity.
  • Transient dephosphorylation of cdc2 (Tyr15) and cdc25c (Ser216) preceded their downregulation.

Conclusions:

  • TGFbeta directly inhibits G2 checkpoint kinases, primarily at the mRNA expression level.
  • The observed transient activation followed by inhibition of G2 kinases may enhance TGFbeta-mediated G1 arrest and growth inhibition.
  • These findings reveal a novel mechanism by which TGFbeta influences cell cycle progression and growth in leukemia.

More Related Videos

Intracellular Phosphoflow Cytometry of Acute Myeloid Leukemia Patient-Derived Xenotransplants07:38

Intracellular Phosphoflow Cytometry of Acute Myeloid Leukemia Patient-Derived Xenotransplants

Published on: June 6, 2025

Preparation of Primary Acute Lymphoblastic Leukemia Cells in Different Cell Cycle Phases by Centrifugal Elutriation09:09

Preparation of Primary Acute Lymphoblastic Leukemia Cells in Different Cell Cycle Phases by Centrifugal Elutriation

Published on: November 10, 2017

Related Concept Videos

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.
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
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...
The Cell Cycle Control System01:28

The Cell Cycle Control System

The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular regulatory molecules and external triggers. They provide "stop" or "advance" signals and operate at specific cell cycle stages termed checkpoints to ensure that a particular process is completed before the cell advances to the next phase.
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and function at the cell...
Mitogens and the Cell Cycle02:38

Mitogens and the Cell Cycle

Mitogens and their receptors play a crucial role in controlling the progression of the cell cycle. However, the loss of mitogenic control over cell division leads to tumor formation. Therefore, mitogens and mitogen receptors play an important role in cancer research. For instance, the epidermal growth factor (EGF) - a type of mitogen and its transmembrane receptor (EGFR), decides the fate of the cell's proliferation. When EGF binds to EGFR, a member of the ErbB family of tyrosine kinase...
DNA Damage can Stall the Cell Cycle02:36

DNA Damage can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...