Cholesterol-modified sphingomyelin chimeric lipid bilayer for improved therapeutic delivery

Area of Science:

• Biochemistry
• Materials Science
• Nanotechnology

Background:

• Cholesterol (Chol) stabilizes lipid bilayers in liposomes but is extracted in vivo, causing payload leakage and reduced therapeutic efficacy.
• Current liposomal formulations face challenges with membrane instability and premature drug release in physiological environments.

Purpose of the Study:

• To develop a cholesterol-modified sphingomyelin (SM-Chol) lipid bilayer to enhance liposome stability and drug delivery.
• To evaluate the performance of SM-Chol in preventing cholesterol transfer and payload leakage.

Main Methods:

• Covalent conjugation of cholesterol to sphingomyelin to create SM-Chol lipids.
• Structure-activity relationship screening to optimize SM-Chol linker and bond type.
• In vivo evaluation in various cancer xenograft and orthotopic animal models (lymphoma, pancreas, breast, colorectal cancer).

Main Results:

• Optimized SM-Chol with a disulfide bond and longer linker effectively blocked cholesterol transfer and payload leakage.
• SM-Chol formulations demonstrated improved pharmacokinetics, enhanced tumor delivery, and increased maximum tolerated dose for vincristine.
• Improved therapeutic delivery of diverse agents (chemotherapeutics, siRNA) and enhanced antitumor efficacy in multiple cancer models compared to controls.

Conclusions:

• SM-Chol represents a stable and effective platform for liposome-mediated drug delivery.
• This modified lipid composition overcomes limitations of conventional liposomes, offering potential for improved cancer therapy and delivery of various therapeutic agents.