Liposomes generated from proliposomes for treatment of glioma using Momordica charantia extracts

Abstract

Every year there is 2% increase in the reported cases of glioma. It is important to treat glioma from materials that are readily available in nature. One of the interesting properties of liposomes is their ability to target tumours and facilitate the cellular uptake of therapeutic agents compared to the agent alone. In this project, liposomes were prepared from SPC (Soy phosphatidylcholine) and HSPC (Hydrogenated soy phosphatidylcholine) phospholipids. Drug-free liposomes prepared by proliposomes were compared with the conventional method of producing liposomes. Conventional liposomes are biocompatible and biodegradable, however, they are physically and chemically unstable. The instability problems were avoided by formulating liposomes using the ethanol-based proliposome technology. In ethanol-based proliposome method, aqueous phase (e.g. water) was added to an ethanolic solution of phospholipid to generate liposomes. In this work, natural anticancer materials such as Paclitaxel (PTX) and Momordica charantia extracts (Whole fruit, Fruit alone and Seed alone) from Africa, China and India were incorporated in liposome formulations. These liposomes were analysed by investigating, the resultant size, size distribution and zeta potential of the vesicles. Either, the anticancer drug or extract of Momordica charantia was mixed with liposomes and checked for the efficacy of the anticancer-liposome formulations on the viability of glioma cell lines and the molecular mechanism of the cell death were also investigated. The results show that liposomes prepared by the conventional thin- film method were comparatively large in size as compared to liposomes generated from proliposomes. Liposomes generated from proliposomes (made from SPC or HSPC), when generated by hydration with Momordica charantia extracts (WF – Whole fruit, FA – Fruit alone or SA – Seed alone) from Africa, China or India respectively, or when prepared using PTX in the lipid phase had significantly larger size and wider size distribution as compared to drug free liposomes. Liposomes generated from proliposomes were neutral or negatively charged and were a mixture of oligolamellar and multilamellar vesicles regardless of formulation. Particle size and size distribution of HSPC liposomes were larger than SPC liposomes on inclusion of either Paclitaxel or Momordica charantia extracts. Liposome generated by proliposome method using the Momordica charantia extracts (FA, SA and WF) exerted cytotoxic effects against glioma cells 1321N1, Gos-3 and U87-MG at the higher concentrations with or without liposomes. Momordica charantia extracts showed either slight or no significant effect on the normal glial cells. The liposome formulations were more effective against glioma cells as compared to drug-free liposomes. FA extract of Momordica charantia was very effective with and without liposomes but less than PTX liposomes. The activities of caspase 3/7, caspase 9 and cytochrome c release were elevated in cancerous glial cell line indicating apoptosis via mitochondrial cell death or intrinsic pathway.

In conclusion, the study showed that liposomes generated from proliposomes were appropriate to target cancerous glial cells by binding plant extracts Momordica charantia and PTX to SPC and HSPC phospholipids. The cell death was induced by apoptosis via mitochondrial cell death.