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Updated: May 24, 2026

Flow Cytometric Analysis of Apoptotic Biomarkers in Actinomycin D-Treated SiHa Cervical Cancer Cells
13:53

Flow Cytometric Analysis of Apoptotic Biomarkers in Actinomycin D-Treated SiHa Cervical Cancer Cells

Published on: August 26, 2021

Conditioned medium from actinomycin D-treated apoptotic cells induces mitochondria-dependent apoptosis in bystander

Cuihong Jin1, Shengwen Wu, Xiaobo Lu

  • 1Department of Toxicology, School of Public Health, China Medical University, Shenyang 110001, PR China.

Toxicology Letters
|March 17, 2012
PubMed

Insights

Chemicals can trigger bystander effects, causing apoptosis in nearby cells. This study reveals that conditioned medium from actinomycin D-treated cells activates the p53-Bcl-2/Bax-cytochrome c pathway, leading to cell death.

Area of Science:

  • Cellular and Molecular Biology
  • Toxicology
  • Genetics

Background:

  • Chemical-induced bystander effects are known but poorly understood.
  • Previous studies showed mitomycin C and phleomycin induce micronuclei in bystander cells.
  • Actinomycin D (ACTD) induces bystander effects, with conditioned medium (CM) from ACTD-exposed cells causing apoptosis in bystander cells.

Purpose of the Study:

  • To elucidate the mechanism of apoptosis in bystander cells induced by ACTD-treated CM.
  • To investigate the role of specific signaling pathways and cellular responses in ACTD-induced bystander apoptosis.

Main Methods:

  • Culturing Chinese hamster V79 cells and treating them with ACTD.
  • Collecting conditioned medium (CM) from ACTD-exposed cells.
  • Analyzing apoptosis in bystander cells using morphological assessment, Western blotting, RT-PCR, and measuring mitochondrial membrane potential and cytochrome c release.
  • Assessing cell cycle progression using flow cytometry.

Main Results:

  • ACTD-treated CM induced apoptosis in bystander cells in a time-dependent manner.
  • Increased mRNA and protein levels of p53 and Bax, and decreased Bcl-2 levels were observed in bystander cells.
  • Reactive oxygen species (ROS) generation, reduced mitochondrial membrane potential, and cytochrome c release were detected.
  • G1 cell phase arrest occurred in bystander cells exposed to ACTD-treated CM.

Conclusions:

  • ACTD-treated CM induces apoptosis in bystander cells via the mitochondria pathway, involving p53-Bcl-2/Bax-cytochrome c signaling.
  • The bystander apoptosis response is time-dependent and involves ROS generation and cell cycle arrest.
  • This study provides mechanistic insights into chemical-induced bystander effects.

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