Related Experiment Video

Updated: Jul 29, 2026

Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death
13:54

Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death

Published on: October 21, 2012

Flavopiridol-induced apoptosis is mediated through up-regulation of E2F1 and repression of Mcl-1

Yihong Ma1, W Douglas Cress, Eric B Haura

  • 1Experimental Therapeutics Programs, H. Lee Moffitt Cancer Center and Research Institute, and Department of Interdisciplinary Oncology, University of South Florida College of Medicine, Tampa, Florida 33612, USA.

Molecular Cancer Therapeutics
|January 21, 2003
PubMed

Insights

Flavopiridol induces apoptosis in lung cancer cells by increasing E2F1 protein and decreasing Mcl-1 levels. This mechanism, involving E2F1 stabilization and Mcl-1 repression, is crucial for flavopiridol

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Death Mechanisms

Background:

  • Flavopiridol (a cyclin-dependent kinase inhibitor) induces apoptosis, potentially via Mcl-1 down-regulation.
  • E2F1 transcription factor has been shown to repress Mcl-1, leading to apoptosis.
  • Cyclin/cyclin-dependent kinase 2 antagonists kill transformed cells, suggesting a role for E2F1 stabilization.

Purpose of the Study:

  • To investigate if flavopiridol stabilizes E2F1 and enhances apoptosis through Mcl-1 repression.
  • To elucidate the role of E2F1 and Mcl-1 in flavopiridol-induced apoptosis in lung carcinoma cells.

Main Methods:

  • Dose-dependent analysis of flavopiridol treatment on E2F1 and Mcl-1 protein levels in H1299 lung carcinoma cells.
  • Assessment of apoptosis induction following flavopiridol treatment.
  • Utilizing RNA interference (RNAi) to delete E2F1 in H1299 cells.
  • Evaluating flavopiridol sensitivity in cell lines with constitutive Mcl-1 expression or E2F1 deficiency.

Main Results:

  • Flavopiridol treatment caused a dose-dependent increase in E2F1 protein and a corresponding decrease in Mcl-1 levels in H1299 cells within 12 hours.
  • The observed changes in E2F1 and Mcl-1 preceded the induction of apoptosis.
  • Cell lines with constitutive Mcl-1 expression or E2F1 deficiency exhibited resistance to flavopiridol-induced apoptosis.
  • E2F1 deletion via RNAi reduced sensitivity to flavopiridol-induced cell death.

Conclusions:

  • Flavopiridol-induced apoptosis in lung carcinoma cells is dependent on the enhancement of E2F1 levels.
  • The repression of Mcl-1, mediated by elevated E2F1, is a key mechanism in flavopiridol's apoptotic effect.
  • E2F1 and Mcl-1 are critical mediators of flavopiridol's anti-cancer activity.

More Related Videos

Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling08:51

Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling

Published on: June 25, 2015

A Murine Cell Line Based Model of Chronic CDK9 Inhibition to Study Widespread Non-Genetic Transcriptional Elongation Defects (TEdeff) in Cancers10:49

A Murine Cell Line Based Model of Chronic CDK9 Inhibition to Study Widespread Non-Genetic Transcriptional Elongation Defects (TEdeff) in Cancers

Published on: September 26, 2019

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.
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...
Apoptosis01:30

Apoptosis

Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
The Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
The Intrinsic Apoptotic Pathway01:31

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Cellular Injury V: Apoptosis and Autophagy01:22

Cellular Injury V: Apoptosis and Autophagy

Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...