Related Experiment Video

Updated: Aug 15, 2026

Detection of Aggregation-Prone Behavior in Mutant P53 V157F Breast Cancer Cells Using Multipoint Thioflavin T Fluorescence
04:56

Detection of Aggregation-Prone Behavior in Mutant P53 V157F Breast Cancer Cells Using Multipoint Thioflavin T Fluorescence

Published on: December 30, 2025

p53-independent pRB degradation contributes to a drug-induced apoptosis in AGS cells

Yan Jin1, Wai Keung Leung, Joseph Jao-Yiu Sung

  • 1Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

Cell Research
|October 11, 2005
PubMed

Insights

Tripchlorolide (TC) induces retinoblastoma (RB) protein degradation, promoting apoptosis in gastric tumor cells. This degradation is p53-independent, suggesting a novel therapeutic target for cancer.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Cycle Regulation

Background:

  • The retinoblastoma (RB) protein is a key regulator of the mammalian cell cycle.
  • Evidence suggests RB also plays a role in regulating apoptosis.
  • Gastric tumor cells are a focus for novel anti-cancer therapies.

Purpose of the Study:

  • To investigate the role of RB protein degradation in apoptosis induced by tripchlorolide (TC) in gastric tumor cells.
  • To determine if RB degradation is essential for TC-induced apoptosis.
  • To elucidate the involvement of p53 in TC-induced RB degradation.

Main Methods:

  • Treatment of gastric tumor cells with tripchlorolide (TC).
  • Assay for retinoblastoma (RB) protein degradation.
  • Inhibition of RB degradation using a cysteine protease inhibitor (IDAM).
  • Over-expression of exogenous RB.
  • Utilizing p53 dominant-negative constructs.

Main Results:

  • Tripchlorolide (TC) treatment led to the degradation of RB protein in apoptotic gastric tumor cells.
  • Inhibiting RB degradation with IDAM reduced the number of apoptotic cells.
  • Over-expressing RB enhanced gastric tumor cell survival under TC treatment.
  • TC-induced RB degradation occurred independently of p53.

Conclusions:

  • RB protein degradation is involved in the apoptotic progression of gastric tumor cells treated with TC.
  • The observed RB degradation is a p53-independent mechanism.
  • Targeting RB degradation may represent a novel therapeutic strategy for gastric cancer.

More Related Videos

Procedure and Key Optimization Strategies for an Automated Capillary Electrophoretic-based Immunoassay Method09:32

Procedure and Key Optimization Strategies for an Automated Capillary Electrophoretic-based Immunoassay Method

Published on: September 10, 2017

Yeast As a Chassis for Developing Functional Assays to Study Human P5314:57

Yeast As a Chassis for Developing Functional Assays to Study Human P53

Published on: August 4, 2019

Related Concept Videos

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...
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.
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...
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...
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,...