Cationic liposome co-encapsulation of SMAC mimetic and zVAD using a novel lipid bilayer fusion loaded with MLKL-pDNA for tumour inhibition in vivo

Abstract

The increase in multidrug resistance among colon cancer cells presents a challenge for the development of effective therapies. Small-molecule analogues of second mitochondria-derived activator of caspase (SMAC) mimetic in association with mixed lineage kinase domain-like protein (MLKL)-pDNA and z-VAD-fmk have shown ideal antitumor effects in colon cancer cells in vitro via induction of RIP3-dependent necroptosis. To achieve synergistic antitumor effects in vivo, liposomes loaded with SMAC mimetic, MLKL-pDNA and z-VAD-fmk have been developed using novel lipid fusion methods to co-localise the molecules of interest within the tumour cells. The co-encapsulation liposome (MLKL-zVAD-BV6-LP) had a high entrapment efficiency of approximately 95% for both zVAD and BV6 and was able to condense MLKL-pDNA very well. The vectors showed good biocompatibility, tumour targeting and small-molecule co-localisation. In a CT26 mouse model, the MLKL-zVAD-BV6-LP exhibited a tumour-suppression rate of over 60% in vivo, which was significantly higher than that of both the null-liposome and coadministration groups. Above all, the co-encapsulation system provided a novel approach to combination tumour therapy.

Keywords:

• SMAC mimetic
• zVAD
• MLKL-pDNA
• liposome fusion
• co-encapsulation liposome

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (81001012), the China Postdoctoral Science Foundation (2014T70877, 2013M542421).