Blue Fluorescent Siloxytecans Exhibit Potent Anticancer Activity and Enable Direct Real-Time Quantification of...

Area of Science:

• Medicinal Chemistry
• Chemical Biology
• Pharmacology

Background:

• Silicon-containing compounds are underexplored in pharmaceuticals despite potential benefits.
• Silylation can enhance bioavailability and lipophilicity of natural products.
• Camptothecin analogs are potent anticancer agents but face metabolic challenges.

Purpose of the Study:

• To synthesize and evaluate novel silicon-containing camptothecin analogs (siloxytecans).
• To investigate the impact of silylation on SN-38's antiproliferative activity and fluorescence.
• To utilize enhanced fluorescence for real-time monitoring of intracellular drug uptake and mechanism of action.

Main Methods:

• Synthesis of C-10 silyl ether modified SN-38 analogs.
• Antiproliferative assays against a panel of cancer cell lines.
• Quantitative fluorescence microscopy for visualizing intracellular uptake.
• Flow cytometry for cell cycle analysis.
• Cell-free assays for topoisomerase I inhibition.

Main Results:

• Siloxytecans demonstrated comparable dose- and time-dependent antiproliferative activity to SN-38.
• Silylation enhanced bright-blue fluorescence, enabling real-time, quantitative visualization of cellular uptake.
• Fluorescence microscopy revealed uptake dynamics consistent with washout experiments.
• Siloxytecans retained topoisomerase I inhibitory properties.

Conclusions:

• Silicon incorporation is a viable strategy for developing novel camptothecin analogs.
• Enhanced fluorescence provides a powerful tool for studying drug transport and mechanism.
• Siloxytecans represent a promising class of anticancer agents with potential for mechanistic investigation.