Cancer is one of the most devastating diseases worldwide, accounting near 10 million deaths in 2020 [1]. In response to this issue, not only do therapeutic options are aimed to be improved but also prevention programs are being developed. For example, a chemopreventive substances are considered to lower a person's risk of (re)developing cancer [2]. However, minority of people, even if they are acknowledged of genetic predisposition to cancer, choose to use chemotherapy drugs because of severe side effects. Natural substances are thought to be free of severe side effects and would therefore be more accepted and used by the target group.
Curcumin is one of the naturally occurring substances that is considered to have anti-cancer properties [3], and therefore, having potential as a cancer chemopreventive agent. Nevertheless, curcumin is a hydrophobic compound and is poorly absorbed by a living organism. Encapsulation of curcumin in phospholipid liposomes could facilitate absorption since liposomes have a desired bioavailability and are biocompatible as well as biodegradable. However, the comparison of encapsulation techniques in terms of cellular uptake and localization in biological models is still limited.
The aim of our study was to evaluate the effect of liposomal curcumin on breast cancer cell line (MCF-7) and to identify liposomal curcumin localization in the cell. In our research we synthesized liposomal curcumin solution applying a thin-film and pH-differences methods. MCF-7 breast cancer cell line was used to evaluate liposomal curcumin effects on cancer cells. As a control, liposomes without curcumin were synthesized to eliminate the possible effect of liposomes. For the assessment of accumulation of liposomal curcumin in cancer cells, confocal microscopy imaging with fluorescent dyes labeling were applied. Particle size, zeta potential and encapsulation efficiency were assessed to characterize the liposomes.
The cell morphology, viability and proliferation test results showed toxicity of curcumin to breast cancer cell line and preliminary results from confocal microscopy images indicated an accumulation of curcumin in the cytoplasm at the lysosomal sites. No uptake of liposomal curcumin into the nucleus or mitochondria was observed. When it comes to comparison of synthesis methods, we found that liposomal curcumin solutions of both syntheses had similar effect on MCF-7 cells morphology, viability and proliferation, although thin-film synthesis resulted in higher yield. In conclusion, preliminary results suggest that liposomal curcumin has a potential as a chemopreventive agent, and a thin-film synthesis method is advantageous over the pH difference synthesis method.