Effects of hypericin encapsulated on Pluronic F127 photodynamic therapy against triple negative breast cancer.

OBJECTIVE: Breast cancer (BC) currently has no effective treatment especially for the highly aggressive and metastatic triple negative breast cancer (TNBC). Here, we investigated the antitumoral and antimigratory effects of hypericin (HYP) encapsulated on Pluronic F127 (F127/HYP) photodynamic therapy (PDT) against TNBC cell line MDA-MB-231 compared to a nontumorigenic human breast ductal cell line (MCF-10A). METHODS: The phototoxicity/cytotoxicity was assessed by MTT assay, long-term cytotoxicity by clonogenic assay, cell uptake, subcellular distribution, and cellular oxidative stress by fluorescence microscopy, cell death with annexin V-FITC/propidium iodide, PDT mechanism using sodium azide and D-mannitol, and cell migration by wound-healing assay. RESULTS: The treatment promoted phototoxic effect on tumor cell line in a dose-dependent and selective manner. Internalization of F127/HYP was efficient and accumulation occurred in the endoplasmic reticulum and mitochondria, resulting in cellular oxidative stress mainly by the type II mechanism, induced by necrosis. Furthermore, F127/HYP decreased colony formation and reduced the cell migration ability in MDA-MB-231 cells. CONCLUSION: Our results suggest a potentially useful role of F127/HYP micelles as a platform for HYP delivery to more specifically and effectively treat TNBC.

Hypericin photodynamic activity in DPPC liposome. PART I: biomimetism of loading, location, interactions and thermodynamic properties.

Hypericin (Hyp) is a potential photosensitizer drug for Photodynamic Therapy (PDT). However, the high lipophilicity of Hyp prevents its preparation in water. To overcome the Hyp solubility problem, this study uses the liposomal vesicle of DPPC. Otherwise liposome is also one of the most employed artificial systems that mimetizes cell membranes. Our present focus is the interaction of Hyp into DPPC liposome as biomimetic system. We studied the loading, interaction, and localization of Hyp (2.8 µmol L-1) in DPPC (5.4 mmol L-1) liposomes, as well as the thermodynamic aspects of Hyp-liposomes. The Hyp addition to the DPPC liposome dispersion showed a Encapsulation Efficiency for [Hyp] = 2.8 µmol L-1 in [DPPC] = 5.3 mmol L-1 of 74.3% and 89.3% at 30.0 and 50.0 °C, respectively. The encapsulation profile obeys a pseudo first-order kinetic law, with a rate constant of 1.26 × 10-3 s-1 at 30.0 °C. Also the data suggests this reaction is preceded by an extremely rapid step. A study on the binding of Hyp/DPPC liposomes (Kb), performed at several temperatures, showed results of 4.8 and 18.5 × 103 L mol-1 at 293 and 323 K, respectively. Additionally, a decrease was observed in the ΔG of the Hyp/DPPC interaction (-20.6 and - 26.4 kL mol-1 at 293 and 323 K, respectively). The resulting ΔH > 0 with ΔS < 0 shows that the entropy is driven the process. Studies of Hyp location in the liposome at 298 K revealed the existence of two different Hyp populations with a Stern-Volmer constant (Ksv) of 4.65 and 1.87 L mol-1 using iodide as an aquo-suppressor at concentration ranged from 0 to 0.025 mol L-1 and from 0.025 to 0.150 mol L-1, respectively. Furthermore, studies of Fluorescence Resonance Energy Transfer, using DPH as a donor and Hyp as an acceptor, revealed that Hyp is allocated in different binding sites of the liposome. This is dependent on temperature. Thermal studies revealed that the Hyp/DPPC formulation presented reasonable stability. Size and morphological investigations showed that Hyp incorporation increases the average size of DPPC liposomes from 116 to 154 nm. The study demonstrated the ability of the Hyp-DPPC liposome as an interesting system for drug delivery system that can be applied to PDT.