Triple-negative breast cancer (TNBC) is a highly aggressive type of cancer with limited therapeutic options. However, this type of cancer cells has shown overexpression of folate receptors, which bind with folic acid (FA) with high affinity. This feature can be used for targeting of nanocarriers, such as liposomes. In order to further examine the potential of increased efficacy by targeting the folate receptor, we prepared folate conjugated liposomes (DSPC/Chol/PEG/DSPE-PEG-FA) and loaded them with doxorubicin (DOX), an anticancer drug. For this, we first synthesized and verified the conjugate between FA and PEG-lipid (FA-PEG-lipid). After that, liposomes were prepared with thin film hydration method followed by probe sonication. Three different types of targeted liposomes having different concentrations of FA-PEG-lipid in their membranes (0.1 mol%, 0.5 mol%, and 1 mol%) were evaluated for their cytotoxicity (DOX-loaded liposomes) on MDA-MB-231 (epithelial human breast cancer cells), 4T1 (murine mammary carcinoma cells), and MCF7 (Human breast cancer cells); the two first are TNBC cells and overexpress FA receptor, the third does not. Cytotoxicity results proved that increasing amounts of FA on the surface of liposomes results in enhanced antitumor activity of liposomal-DOX in the case of the cancer cells, which overexpress the FA receptor.

Arsonoliposomes (ARSL) constitute a particular class of liposomes that incorporate arsonolipids (ARS) into their membranes. ARSL realize selective toxicity to cancer cells; thus, they are an important tool in the treatment of cancer. Folic acid (FA) is widely used in targeted drug delivery due to its high affinity for the folate receptors that are overexpressed in cancer cell membranes. The aim of our studies was to develop novel triple-negative breast cancer (TNBC)-targeted ARSL by incorporating folic acid-conjugated polyethylene-glycol PEG-lipid (FA-PEG-lipid) into their membrane and loading them with anticancer drug doxorubicin (DOX). ARSL incorporating 0.1 mol% of FA-PEG-lipid were prepared and loaded with DOX, using the active loading protocol. They were characterized for their size distribution, zeta potential and drug entrapment efficiency (%). Their cytotoxic activity towards TNBC cell lines, particularly MDA-MB-231 (epithelial human breast cancer cells) and MCF7 (human breast cancer cells), was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT-assay. The first results demonstrated enhanced toxicity of this novel type of ARSL towards cancer cells, which is particularly interesting and deserves further exploitation.