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Published on: February 16, 2015
Caspase-3/-7-Specific Metabolic Precursor for Bioorthogonal Tracking of Tumor Apoptosis
Man Kyu Shim1, Hong Yeol Yoon2, Sangmin Lee3
1Department of Pharmacy, Graduate School, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
Abstract:
Apoptosis is one of the most important intracellular events in living cell, which is a programmed cell death interrelated with caspase enzyme activity for maintaining homeostasis in multicellular organisms. Therefore, direct apoptosis imaging of living cells can provide enormous advantages for diagnosis, drug discovery, and therapeutic monitoring in various diseases. However, a method of direct apoptosis imaging has not been fully validated, especially for live cells in in vitro and in vivo. Herein, we developed a new apoptosis imaging technology via a direct visualization of active caspase-3/-7 activity in living cells. For this, we synthesized a caspase-3/-7-specific cleavable peptide (KGDEVD) conjugated triacetylated N-azidoacetyl-D-mannosamine (Apo-S-Ac3ManNAz), wherein the Apo-S-Ac3ManNAz can be cleaved by the active caspase-3/-7 in live apoptotic cells and the cleaved Ac3ManNAz molecules can further generate targetable azido groups (N3) on the living cell surface. Importantly, the azido groups on the apoptotic tumor cells could be visualized with Cy5.5-conjugated dibenzylcyclooctyne (DBCO-Cy5.5) via bioorthogonal click chemistry in vitro cell culture condition and in vivo tumor-bearing mice. Therefore, our Apo-S-Ac3ManNAz can be utilized for the further applications in tumor therapy as a monitoring tool for anticancer efficacy and optimization of anticancer new drugs in cell culture system and in tumor-bearing mice.
Insights
We developed a novel apoptosis imaging technology to visualize active caspase-3/-7 in living cells. This method enables direct tracking of programmed cell death for improved disease diagnosis and drug development.
Area of Science:
- Biomedical Imaging
- Molecular Biology
- Cellular Biology
Background:
- Apoptosis, or programmed cell death, is crucial for maintaining homeostasis and is linked to caspase enzyme activity.
- Direct apoptosis imaging in living cells offers significant potential for disease diagnosis, drug discovery, and therapeutic monitoring.
- Current methods for direct apoptosis imaging in live cells (in vitro and in vivo) require further validation.
Purpose of the Study:
- To develop and validate a novel technology for direct apoptosis imaging in living cells.
- To visualize active caspase-3/-7 activity in real-time within apoptotic cells.
- To establish a tool for monitoring therapeutic efficacy and optimizing drug development.
Main Methods:
- Synthesized a caspase-3/-7-specific peptide (KGDEVD) conjugated to triacetylated N-azidoacetyl-D-mannosamine (Apo-S-Ac3ManNAz).
- Demonstrated that Apo-S-Ac3ManNAz is cleaved by active caspases in apoptotic cells, generating cell surface azido groups (N3).
- Utilized bioorthogonal click chemistry with DBCO-Cy5.5 to visualize azido-modified apoptotic cells in vitro and in vivo tumor models.
Main Results:
- Successfully visualized active caspase-3/-7 activity in living apoptotic cells using Apo-S-Ac3ManNAz.
- Confirmed the generation of targetable azido groups on the surface of apoptotic cells post-cleavage.
- Demonstrated successful in vitro and in vivo imaging of apoptotic tumor cells in tumor-bearing mice.
Conclusions:
- Apo-S-Ac3ManNAz provides a direct visualization method for active caspase-3/-7 in living cells.
- This technology enables non-invasive monitoring of apoptosis in cellular and animal models.
- The developed apoptosis imaging tool holds promise for applications in tumor therapy, anticancer drug efficacy monitoring, and new drug optimization.
Related Concept Videos
01:24Caspases
01:17The Extrinsic Apoptotic Pathway
01:31The Intrinsic Apoptotic Pathway
01:30Apoptosis