Related Experiment Video

Updated: May 22, 2026

Immunofluorescence Imaging of DNA Damage and Repair Foci in Human Colon Cancer Cells
05:18

Immunofluorescence Imaging of DNA Damage and Repair Foci in Human Colon Cancer Cells

Published on: June 9, 2020

E2F1-dependent pathways are involved in amonafide analogue 7-d-induced DNA damage, G2/M arrest, and apoptosis in

Yiquan Li1, Jin Shao, Ke Shen

  • 1State Key Laboratory of Bioreactor Engineering & Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, #268, 130 Meilong Road, Shanghai 200237, PR China.

Journal of Cellular Biochemistry
|May 18, 2012
PubMed

Insights

A novel compound, 7-d, effectively targets p53-deficient Chronic Myelogenous Leukemia (CML) cells by inducing DNA damage and activating the E2F1-dependent apoptotic pathway. This compound demonstrates significant antitumor activity through a p53-independent mechanism, offering a potential new therapeutic strategy.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Pharmacology

Background:

  • The E2F1 gene is crucial for cell cycle regulation, particularly the G1 to S phase transition.
  • The salvage antitumoral pathway involving E2F1, especially in p53-deficient cancers, remains incompletely understood.
  • p53-deficient cancers, like Chronic Myelogenous Leukemia (CML), present unique therapeutic challenges.

Purpose of the Study:

  • To elucidate the upstream and downstream events in the E2F1-dependent pro-apoptotic pathway.
  • To investigate the anti-leukemic effects of a novel compound, 7-d, against p53-deficient CML cells.
  • To identify the specific molecular mechanisms underlying 7-d's antitumor activity.

Main Methods:

  • Screening of a benzisoquinoline analogue, 7-d, for antitumor activity.
  • Flow cytometry and western blot analysis of K562 cells treated with 7-d.
  • Assessment of DNA double-strand breaks (DSB) using comet tail assay and γ-H2AX expression.
  • Inhibition of ATM/ATR signaling with caffeine to evaluate pathway involvement.
  • E2F1 knockout experiments to confirm its role in 7-d's effects.

Main Results:

  • 7-d exhibited significant antitumor activity against p53-deficient CML K562 cells.
  • 7-d induced dose- and time-dependent G2/M cell cycle arrest and apoptosis via a p53-independent pathway.
  • Treatment with 7-d caused DNA double-strand breaks (DSB) and activated ATM/ATR signaling.
  • 7-d increased the expression of E2F1, p73, and Apaf-1, with p73 dissociating from HDM2.
  • E2F1 knockout reversed 7-d-induced apoptosis and reactivated cell cycle progression.

Conclusions:

  • 7-d effectively inhibits the growth of p53-deficient CML cells.
  • The compound activates an E2F1-dependent mitochondrial and cell cycle checkpoint signaling pathway.
  • 7-d's mechanism involves targeting p73, Apaf-1, and p21(Cip1/WAF1) in a p53-independent manner.
  • These findings highlight 7-d as a potential therapeutic agent for p53-deficient CML.

More Related Videos

Proximity Ligand Assay to Localize Proteins in DNA Damage Sites09:39

Proximity Ligand Assay to Localize Proteins in DNA Damage Sites

Published on: August 2, 2024

Detection and Visualization of DNA Damage-induced Protein Complexes in Suspension Cell Cultures Using the Proximity Ligation Assay13:10

Detection and Visualization of DNA Damage-induced Protein Complexes in Suspension Cell Cultures Using the Proximity Ligation Assay

Published on: June 9, 2017

Related Concept Videos

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...
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...
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...
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...
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.
Long-patch Base Excision Repair01:02

Long-patch Base Excision Repair

Since the discovery of the two BER pathways, there has been a debate about how a cell chooses one pathway over the other and the factors determining this selection. Numerous in vitro experiments have pointed out multiple determinants for the sub-pathway selection. These are: