Self-assembled supramolecular nanomicelles from a bile acid–docetaxel conjugate are highly tolerable with improved therapeutic efficacy

Abstract

Herein, we present the engineering of a supramolecular nanomicellar system that is composed of self-assembled units of the PEGylated lithocholic acid (LCA)–docetaxel (DTX) conjugate (LCA-DTX-PEG). We tethered a short polyethylene glycol unit to LCA and used an esterase-sensitive ester linkage between DTX and LCA. The LCA-DTX-PEG conjugate formed nanomicelles (LCA-DTX-PEG NMs) with ∼160 nm hydrodynamic diameter that are sensitive to cellular esterases and maximized the release of DTX under high esterase exposure. LCA-DTX-PEG NMs were found to be effective as the parent drug in breast cancer cells by stabilizing tubulin and arresting the cells in the G₂/M phase. We determined the maximum tolerated dose (MTD) and systemic and vital organ toxicity of LCA-DTX-PEG NMs in mice, rats, and rabbits. LCA-DTX-PEG NMs showed a MTD of >160 mg kg⁻¹ and are found to be safe in comparison with their parent FDA-approved drug formulation (Taxotere® or DTX-TS) that is highly toxic. LCA-DTX-PEG NMs effectively reduced the tumor volume and increased the survival of 4T1 tumor-bearing mice with improved blood circulation time of the drug and its higher accumulation in tumor tissues. Therefore, this study highlights the potential of PEGylated bile acid–drug conjugate based nanomicelles for the development of next generation cancer therapeutics.