Dynamic Simulations of Interaction of the PEG-DPPE Micelle-Encapsulated Short-Chain Ceramides with the Raft-Included...

Area of Science:

• Biochemistry
• Cell Biology
• Drug Delivery Systems

Background:

• Lipid rafts in cancer cell membranes regulate signal transduction and drug transport.
• Increased membrane rigidity from lipid rafts hinders drug entry, a challenge in cancer therapy.
• Short-chain ceramides (CERs) are known to enhance drug permeability but their mechanism is unclear.

Purpose of the Study:

• To investigate the mechanism by which short-chain ceramides (CERs) disrupt lipid raft stability.
• To explore the dynamic interaction of PEG-DPPE micelles carrying doxorubicin (DOX) with raft-included cancer cell membranes modulated by CERs.
• To elucidate the role of specific membrane components like cholesterol (CHOL), GM1, and phosphatidylinositol 4,5-bisphosphate (PIP2) in CER-mediated drug delivery.

Main Methods:

• Utilized a phase-segregated membrane model (DPPC/DIPC/CHOL/GM1/PIP2) to simulate cancer cell membranes.
• Investigated the fusion dynamics of PEG-DPPE micelles encapsulating doxorubicin (DOX) with these model membranes.
• Analyzed the effect of varying concentrations of C8 acyl tail ceramides (CERs) on membrane structure and drug permeability.

Main Results:

• Lipid rafts remained intact and resistant to doxorubicin (DOX) without CERs.
• CERs disorganized lipid rafts by displacing cholesterol (CHOL) from dipalmitoylphosphatidylcholine (DPPC) domains.
• Increased CER concentration enhanced the permeability of PEG-DPPE micelle-encapsulated DOX into the membrane, with GM1 and PIP2 further facilitating drug redistribution.

Conclusions:

• Short-chain ceramides (CERs) effectively disorganize lipid raft stability in cancer cell membranes.
• This disruption enhances the penetration of micelle-encapsulated drugs like doxorubicin (DOX).
• Findings offer a novel strategy for designing improved drug delivery systems for cancer therapy.