Related Experiment Video

Updated: Aug 20, 2026

Evaluation of Caspase Activation to Assess Innate Immune Cell Death
10:23

Evaluation of Caspase Activation to Assess Innate Immune Cell Death

Published on: January 20, 2023

Alterations in protein expression in HL-60 cells during etoposide-induced apoptosis modulated by the caspase

Ruta Navakauskiene1, Grazina Treigyte, Jurate Savickiene

  • 1Department of Developmental Biology, Institute of Biochemistry, LT-08662 Vilnius, Lithuania. ruta.navakauskiene@bchi.lt

Annals of the New York Academy of Sciences
|January 22, 2005
PubMed

Insights

DNA topoisomerase inhibitors trigger apoptosis, a programmed cell death process. This study reveals that inhibiting caspases blocks etoposide-induced DNA damage and cell death, highlighting initial caspase-dependent signaling events.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • DNA topoisomerase inhibitors are crucial chemotherapeutic agents.
  • These drugs initiate apoptosis, a programmed cell death pathway.
  • The early signaling events driving this process remain largely uncharacterized.

Purpose of the Study:

  • To investigate the initial caspase-dependent signaling events induced by etoposide (VP16).
  • To compare the effects of etoposide alone versus etoposide combined with a caspase inhibitor (ZVAD.fmk) on apoptosis.
  • To identify proteins involved in early caspase-dependent signaling during etoposide-induced apoptosis.

Main Methods:

  • Apoptosis assessment using cell morphology and DNA fragmentation analysis (agarose gel electrophoresis).
  • Western blot analysis to evaluate protein expression (proliferating cell nuclear antigen, Bcl-2, actin).
  • Proteomic screening to identify upregulated proteins in a caspase-dependent manner.

Main Results:

  • ZVAD.fmk significantly inhibited etoposide-induced DNA fragmentation and reduced the number of apoptotic cells.
  • Etoposide treatment altered the expression of proliferating cell nuclear antigen, Bcl-2, and actin.
  • Several proteins were found to be upregulated in the cytoplasm and subsequently accumulated in the nucleus following etoposide treatment, a process partially inhibited by ZVAD.fmk.

Conclusions:

  • Caspase activity is essential for etoposide-induced DNA fragmentation and apoptosis.
  • Specific proteins accumulate in the nucleus in a caspase-dependent manner, suggesting their role in initiating apoptotic signaling cascades.
  • These findings elucidate early molecular events in etoposide-induced programmed cell death.

More Related Videos

Analysis of Apoptosis in Zebrafish Embryos by Whole-mount Immunofluorescence to Detect Activated Caspase 308:20

Analysis of Apoptosis in Zebrafish Embryos by Whole-mount Immunofluorescence to Detect Activated Caspase 3

Published on: December 20, 2013

Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death13:54

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

Related Concept Videos

Caspases01:24

Caspases

Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
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...
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...