Related Experiment Video

Updated: Aug 31, 2026

Exploring Caspase Mutations and Post-Translational Modification by Molecular Modeling Approaches
05:56

Exploring Caspase Mutations and Post-Translational Modification by Molecular Modeling Approaches

Published on: October 13, 2022

A serine protease is involved in the initiation of DNA damage-induced apoptosis

E C de Bruin1, D Meersma, J de Wilde

  • 1Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.

Cell Death and Differentiation
|September 23, 2003
PubMed

Insights

A novel serine protease pathway regulates programmed cell death in melanoma cells, impacting poly(ADP-ribose) polymerase (PARP) cleavage during etoposide treatment. This pathway is critical for cell death execution.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Cancer Research

Background:

  • Caspases are key proteases in apoptosis, activating downstream executioners for cellular substrate degradation.
  • Apoptotic cell death involves complex signaling pathways, including caspase activation and substrate cleavage.

Purpose of the Study:

  • To investigate the role of caspases in etoposide-induced apoptotic cell death in a human melanoma cell line.
  • To identify the proteases involved in poly(ADP-ribose) polymerase (PARP) cleavage during etoposide treatment.

Main Methods:

  • Treatment of human melanoma cells with etoposide.
  • Inhibition of caspases using zVAD-fmk (pancaspase inhibitor) and a specific caspase-2 inhibitor.
  • Inhibition of serine proteases using 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF).
  • Assessment of poly(ADP-ribose) polymerase (PARP) cleavage and DEVDase activity.

Main Results:

  • The pancaspase inhibitor zVAD-fmk failed to block PARP cleavage but inhibited DEVDase activity.
  • A specific caspase-2 inhibitor did not prevent etoposide-induced PARP cleavage.
  • The serine protease inhibitor AEBSF blocked both caspase activation and PARP degradation.
  • Combined treatment with zVAD-fmk and AEBSF significantly protected melanoma cells from etoposide-induced death.

Conclusions:

  • A serine protease regulates an alternative initiation mechanism for caspase activation and PARP cleavage in etoposide-treated melanoma cells.
  • This novel serine protease-dependent pathway plays a critical role in executing etoposide-induced programmed cell death.
  • Targeting this pathway offers a potential strategy for protecting melanoma cells from chemotherapy-induced apoptosis.

More Related Videos

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation08:47

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation

Published on: March 5, 2018

In Vitro Cleavage Assays using Purified Recombinant Drosophila Caspases for Substrate Screening08:16

In Vitro Cleavage Assays using Purified Recombinant Drosophila Caspases for Substrate Screening

Published on: October 6, 2022

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.
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...
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 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...
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.