The self-assembling camptothecin-tocopherol prodrug: An effective approach for formulating camptothecin

Area of Science:

• Nanomedicine
• Drug Delivery
• Cancer Therapeutics

Background:

• Camptothecin (CPT) is a potent topoisomerase I inhibitor with significant antitumor activity.
• Clinical use of CPT is limited by poor solubility, lactone ring instability, and systemic toxicity.
• Existing formulations are inadequate for CPT delivery.

Purpose of the Study:

• To develop novel CPT prodrugs with improved solubility and stability.
• To create self-assembled nanostructures for effective CPT delivery.
• To evaluate the efficacy of CPT prodrug nanoassemblies in a preclinical cancer model.

Main Methods:

• Conjugation of CPT to α-tocopherol via carbonate ester (CPT-VE) or disulfide linkage (CPT-S-S-VE).
• Self-assembly of prodrugs into nanofibers using a PEG5K-Fmoc-VE2 nanomicellar carrier.
• In vitro cytotoxicity assays and in vivo biodistribution and tumor growth inhibition studies in a murine breast cancer model.

Main Results:

• Both CPT prodrugs formed stable nanofibers with the PEG5K-Fmoc-VE2 carrier.
• PEG5K-Fmoc-VE2/CPT-S-S-VE exhibited enhanced cytotoxicity against tumor cells compared to PEG5K-Fmoc-VE2/CPT-VE.
• The CPT-S-S-VE prodrug was effectively converted to CPT in tumor tissues.
• PEG5K-Fmoc-VE2/CPT-S-S-VE nanofibers demonstrated superior tumor growth inhibition in the 4T1.2 breast cancer model.

Conclusions:

• Novel CPT prodrugs, CPT-VE and CPT-S-S-VE, were successfully synthesized and formulated into stable nanofibers.
• The disulfide-linked prodrug, CPT-S-S-VE, showed enhanced in vitro and in vivo anticancer efficacy.
• This nanodrug delivery system holds promise for improving CPT-based cancer therapy.