Design and synthesis of fluorogenic substrate-based probes for detecting Cathepsin B activity

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Cathepsin B is implicated in tumor progression, invasion, and metastasis.
• Overexpression of Cathepsin B is linked to aggressive cancer phenotypes.
• Cathepsin B is a target for protease-activated prodrug cancer therapies.

Purpose of the Study:

• To design and synthesize novel "turn on" fluorescent probes for reporting Cathepsin B activity.
• To evaluate the selectivity and efficacy of these probes in biological samples.
• To identify a probe suitable for live-cell imaging and cancer diagnostics.

Main Methods:

• Synthesis of four novel "turn on" fluorescent probes utilizing a dansylcadaverine dye.
• Enzyme activity assays with recombinant human Cathepsin B and cancer cell lysates.
• Confocal microscopy to assess probe performance in live cells and biological samples.

Main Results:

• One probe, functionalized with a p-aminobenzyl alcohol linker, demonstrated selective "turn on" fluorescence in response to Cathepsin B activity.
• The probe effectively reported Cathepsin B activity in enzyme assays and cancer cell lysates.
• Successful application of the probe in live cells, indicating its potential for in vivo imaging.

Conclusions:

• A novel fluorescent probe has been developed for the selective detection of Cathepsin B activity.
• This probe shows promise as a diagnostic and imaging tool for cancers where Cathepsin B is upregulated.
• The findings support the development of Cathepsin B-targeted therapies and diagnostics.