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Castanospermine suppresses CD44 ectodomain cleavage as revealed by transmembrane bioluminescent sensors
1Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abstract:
Cluster of differentiation 44 (CD44) is a single-pass transmembrane glycoprotein that is a widely distributed cell-surface adhesion molecule. CD44 undergoes ectodomain cleavage by membrane-associated metalloproteinases in breast cancer cells. Cleavage plays a critical role in cancer cell migration by mediating the interaction between CD44 and the extracellular matrix. To explore inhibitors of CD44 ectodomain cleavage, we developed two bioluminescent sensors for the detection of CD44 ectodomain cleavage. The sensors were designed as two-transmembrane proteins with split-luciferase fragments, one of which was cyclized by protein trans-splicing of a DnaE intein. These two sensors emit light by the cyclization or the spontaneous complementation of the luciferase fragments. The luminescence intensities decreased upon cleavage of the ectodomain in breast cancer cells. The sensors revealed that castanospermine, an α-glucosidase inhibitor, suppressed the ectodomain cleavage of endogenous CD44 in breast cancer cells. Castanospermine also inhibited breast cancer cell invasion. Thus, the sensors are beneficial tools for evaluating the effects of different inhibitors.
Insights
New bioluminescent sensors detect Cluster of differentiation 44 (CD44) ectodomain cleavage in breast cancer cells. Castanospermine, an alpha-glucosidase inhibitor, was found to suppress this cleavage and inhibit cancer cell invasion.
Area of Science:
- Biochemistry
- Cell Biology
- Oncology
Background:
- Cluster of differentiation 44 (CD44) is a cell-surface glycoprotein involved in cell adhesion.
- CD44 ectodomain cleavage by metalloproteinases is crucial for breast cancer cell migration.
- Identifying inhibitors of CD44 cleavage is important for developing anti-cancer therapies.
Purpose of the Study:
- To develop novel bioluminescent sensors for detecting CD44 ectodomain cleavage.
- To screen for inhibitors of CD44 ectodomain cleavage in breast cancer cells.
Main Methods:
- Development of two-transmembrane bioluminescent sensors utilizing split-luciferase fragments and intein-mediated protein trans-splicing.
- Detection of luminescence changes correlating with CD44 ectodomain cleavage.
- Treatment of breast cancer cells with castanospermine and assessment of CD44 cleavage and cell invasion.
Main Results:
- The developed bioluminescent sensors effectively detected CD44 ectodomain cleavage in breast cancer cells, with luminescence decreasing upon cleavage.
- Castanospermine, an alpha-glucosidase inhibitor, was identified as an inhibitor of endogenous CD44 ectodomain cleavage.
- Castanospermine treatment also led to the inhibition of breast cancer cell invasion.
Conclusions:
- The novel bioluminescent sensors are valuable tools for evaluating inhibitors of CD44 ectodomain cleavage.
- Castanospermine demonstrates potential as a therapeutic agent by suppressing CD44 cleavage and breast cancer cell invasion.
