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Updated: May 31, 2025
Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro
Published on: July 17, 2018
Target-switchable nanoprobe based on BRD4 inhibition for induction and dynamic visualization of the mitochondrial
Ruijie Cao1, Yijing Dang1, Xinyue Liu1
1School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, China.
Abstract:
The exploration of the mitochondrial apoptotic pathway in living cells is of great significance for achieving tumor diagnosis and treatment. However, visualization of the mitochondrial apoptotic pathway induced by specific proteins has rarely been reported. In this paper, we designed and synthesized a fluorescent probe Cy-JQ1 based on the bromodomain-containing protein 4 (BRD4) inhibition. Cy-JQ1 can affect mitochondrial electron chain transfer and reduce the mitochondrial membrane potential, effectively activating the Bcl-2/Bax/caspase-3 signaling pathway at a concentration of 500 nM and then triggering cell apoptosis. Due to its high specificity and excellent fluorescence properties, the switching of Cy-JQ1 from mitochondria to endoplasmic reticulum could be observed. The difference in fluorescence intensity along the perinuclear aggregates could be well defined as ΔXOR and used as a sensitive indicator of apoptosis. Upon conjugating with polyethylene glycol (PEG) containing disulfide bonds, the performance of the formed nanoprobe (Cy-JQ1-S-S-M) is further enhanced by improving pharmacokinetics and tumor-specific accumulation. This study provides a new analytical method for the dynamic visualization of mitochondria-induced apoptosis pathways triggered by specific proteins, as well as for the development of apoptosis-related target drugs.
Insights
Researchers developed a fluorescent probe, Cy-JQ1, to visualize mitochondrial apoptosis triggered by specific proteins. This probe enables dynamic tracking of apoptosis pathways and aids in developing targeted cancer therapies.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Medicine
Background:
- Mitochondrial apoptosis is crucial for cancer diagnosis and treatment.
- Visualizing protein-induced mitochondrial apoptosis in living cells remains challenging.
Purpose of the Study:
- To design and synthesize a fluorescent probe for visualizing protein-induced mitochondrial apoptosis.
- To develop a sensitive indicator for apoptosis dynamics.
- To create enhanced nanoprobes for improved drug delivery and tumor targeting.
Main Methods:
- Synthesis of the fluorescent probe Cy-JQ1 targeting bromodomain-containing protein 4 (BRD4).
- Investigation of Cy-JQ1's effect on mitochondrial membrane potential and apoptosis signaling pathways (Bcl-2/Bax/caspase-3).
- Development of a nanoprobe (Cy-JQ1-S-S-M) by conjugating Cy-JQ1 with PEG-disulfide bonds.
Main Results:
- Cy-JQ1 effectively triggers apoptosis at 500 nM by impacting mitochondrial function and activating key signaling proteins.
- The probe exhibits specific fluorescence properties, allowing visualization of its translocation from mitochondria to the endoplasmic reticulum.
- A novel apoptosis indicator, ΔXOR, was defined based on fluorescence intensity differences.
- The Cy-JQ1-S-S-M nanoprobe demonstrated improved pharmacokinetics and tumor accumulation.
Conclusions:
- Cy-JQ1 provides a novel method for dynamic visualization of mitochondria-induced apoptosis pathways.
- The developed probe and nanoprobe are valuable tools for studying apoptosis and developing targeted cancer therapies.
- This approach facilitates the development of apoptosis-related targeted drugs.
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