Cationic liposomes, loaded with m-THPC, in photodynamic therapy for malignant glioma

In this study we investigated the feasibility of mixed liposomes formed by dimyristoyl-sn-glycero-phosphatidylcholine (DMPC) and cationic gemini surfactant (Gemini 1) loaded with the chlorin m-tetrahydroxyphenylchlorin (m-THPC), in photodynamic therapy (PDT) for glioma. To this aim, an in vitro study was carried out by employing various human glioblastoma cell lines (A172, DBTRG, LN229, U118). The following liposomal formulations were tested: (i) DMPC and Gemini 1; (ii) m-THPC in DMPC in the absence or (iii) in the presence of Gemini 1 in the molar ratio 8:2; 7:3, and 6:4. The presence of Gemini 1 significantly increased the intracellular uptake of chlorin in all cell tested although with a different extent: LN229 > U118 > A172 > DBTRG. The cytotoxicity of chlorin-loaded liposomes was then tested by cloning efficiency performed on different cultures, before and after irradiation with laser light at 652 nm, at a Fluence Rate of 200 mW/s for 100 s, with a total Fluence of 20 J/cm^-2. In the absence of irradiation, the different liposomal formulations induced a cytotoxicity in less than 30% of glioblastoma cells. On the contrary, irradiation induced total destruction of all cultures treated with m-THPC/DMPC + Gemini 1 in the ratios 8:2, or 7:3, or 6:4.