Efficient synthesis and photodynamic activity of porphyrin-saccharide conjugates: targeting and incapacitating cancer cells

Since the role of saccharides in cell recognition, metabolism, and cell labeling is well-established, the conjugation of saccharides to drugs is an active area of research. Thus, one goal in the use of saccharide-drug conjugates is to impart a greater specificity toward a given cell type or other targets. Although widely used to treat some cancers and age related macular degeneration, the drugs used in photodynamic therapy (PDT) display poor chemical selectivity toward the intended targets, and uptake by cells most likely arises from passive, diffusional processes. Instead, the specific irradiation of the target tissues, and the formation of the toxic species in situ, are the primary factors that modulate the selectivity in the present mode of PDT. We report herein a two-step method to make nonhydrolyzable saccharide-porphyrin conjugates in high yields using a tetra(pentafluorophenyl)porphyrin and the thio derivative of the sugar. As a demonstration of their properties, the selective uptake (and/or binding) of these compounds to several cancer cell types was examined, followed by an investigation of their photodynamic properties. As expected, different malignant cell types take up one type of saccharide-porphyrin conjugate preferentially over others; for example, human breast cancer cells (MDA-MB-231) absorb a tetraglucose-porphyrin conjugate over the corresponding galactose derivative. Doseametric studies reveal that these saccharide-porphyrin conjugates exhibit varying PDT responses depending on drug concentration and irradiation energy. (1) Using 20 microM conjugate and greater irradiation energy induces cell death by necrosis. (2) When 10-20 microM conjugate and less irradiation energy are used, both necrosis and apoptosis are observed. (3) Using 10 microM and the least irradiation energy, a significant reduction in cell migration is observed, which indicates a reduction in aggressiveness of the cancer cells.     

The Effect of Iron Ion on the Specificity of Photodynamic Therapy with 5-Aminolevulinic Acid

Recently, photodynamic therapy using 5-aminolevulinic acid (ALA-PDT) has been widely used in cancer therapy. ALA administration results in tumor-selective accumulation of the photosensitizer protoporphyrin IX (PpIX) via the heme biosynthetic pathway. Although ALA-PDT has selectivity for tumor cells, PpIX is accumulated into cultured normal cells to a small extent, causing side effects. The mechanism of tumor-selective PpIX accumulation is not well understood. The purpose of the present study was to identify the mechanism of tumor-selective PpIX accumulation after ALA administration. We focused on mitochondrial labile iron ion, which is the substrate for metabolism of PpIX to heme. We investigated differences in iron metabolism between tumor cells and normal cells and found that the amount of mitochondrial labile iron ion in cancer was lower than that in normal cells. This finding could be because of the lower expression of mitoferrins, which are the mitochondrial iron transporters. Accordingly, we added sodium ferrous citrate (SFC) with ALA as a source of iron. As a result, we observed the accumulation of PpIX only in tumor cells, and only these cells showed sensitivity to ALA-PDT. Taken together, these results suggest that the uptake abilities of iron ion into mitochondria play a key role in tumor-selective PpIX accumulation. Using SFC as a source of iron might thus increase the specificity of ALA-PDT effects.     

Two combined photosensitizers: a goal for more effective photodynamic therapy of cancer

Photodynamic therapy (PDT) is a clinically approved therapeutic modality for the treatment of diseases characterized by uncontrolled cell proliferation, mainly cancer. It involves the selective uptake of a photosensitizer (PS) by neoplastic tissue, which is able to produce reactive oxygen species upon irradiation with light, leading to tumor regression. Here a synergistic cell photoinactivation is reported based on the simultaneous administration of two PSs, zinc(II)-phthalocyanine (ZnPc) and the cationic porphyrin meso-tetrakis(4-N-methylpyridyl)porphine (TMPyP) in three cell lines (HeLa, HaCaT and MCF-7), using very low doses of PDT. We detected changes from predominant apoptosis (without cell detachment) to predominant necrosis, depending on the light dose used (2.4 and 3.6 J/cm², respectively). Analysis of changes in cytoskeleton components (microtubules and F-actin), FAK protein, as well as time-lapse video microscopy evidenced that HeLa cells were induced to undergo apoptosis, without losing adhesion to the substrate. Moreover, 24 h after intravenous injection into tumor-bearing mice, ZnPc and TMPyP were preferentially accumulated in the tumor area. PDT with combined treatment produced significant retardation of tumor growth. We believe that this combined and highly efficient strategy (two PSs) may provide synergistic curative rates regarding conventional photodynamic treatments (with one PS alone).     

Interest of RGD-containing linear or cyclic peptide targeted tetraphenylchlorin as novel photosensitizers for selective photodynamic activity

Destruction of the neovasculature is essential for tumor eradication by photodynamic therapy. Since the over-expression of integrins is correlated with tumor angiogenesis, we conjugated a photosensitizer (5-(4-carboxyphenyl)-10,15,20-triphenylchlorin or porphyrin) to the alpha(v)beta(3) integrin specific peptide RGD (H-Arg-Gly-Asp-OH) motif as a common sequence. We reported an efficient solid-phase synthesis of a new family of peptidic photosensitizers with linear or cyclic[RGDfK] RGD motif and compared conjugates in vitro selectivity and photodynamic activity. The conjugates were characterized by (1)H NMR, MALDI, UV-visible spectroscopy and singlet oxygen formation was performed. Chlorins containing linear and constrained RGD motif were incorporated up to 98- and 80-fold more, respectively, than the unconjugated photosensitizer over a 24-h exposure in human umbilical vein endothelial cells (HUVEC) over-expressing alpha(v)beta(3) integrin. Peptidic moiety also led to a non-specific increased cellular uptake by murine mammary carcinoma cells (EMT-6), lacking RGD binding receptors. Survival measurements demonstrated that HUVEC were greatly sensitive to conjugates-mediated photodynamic therapy.     

Influence of hematoporphyrin derivative concentration, incubation time, temperature during incubation and laser dose fractionation on photosensitivity of normal hemopoietic progenitors or leukemic cells

Photodynamic therapy represents a new approach for the local control of cancers. It has recently been claimed that photodynamic therapy mediated by hematoporphyrin derivative (HPD) is selectively more efficient for killing leukemic cells than normal progenitors. To improve this effect, we studied the influence of hematoporphyrin dose, temperature during incubation and/or treatment, hematoporphyrin derivative incubation time, and fractionation of the argon laser light (488-514 nm) used for hematoporphyrin stimulation. Plating efficiency calculated after a 7-day period of growth on collagen gel medium showed a dose-dependent phototoxicity of HPD reaching 0.01% for normal hemopoietic progenitors and 0.001% for leukemic cells (dose = 12.5 micrograms/ml). The 10:1 ratio of normal hemopoietic progenitors to leukemic cells was also found to be the same or increased when temperature was 37 degrees C during incubation and 4 degrees C during laser irradiation. Similar results were also found when incubation time was varied from 75-120 min, or when laser irradiation dose was fractionated into 2 or 3 periods. The ratio of normal progenitors to leukemic cells reached 100:1 when 75 J/cm2 were fractionated into 3 periods after an incubation time of 120 min with 10 micrograms/ml HPD. Selectivity in photodynamic treatment seems to occur between normal hemopoietic progenitors and leukemic cells. The mechanism of this selectivity remains unclear, but experiments with the fractionated irradiation dose suggest that as in radiotherapy, better potentially lethal damage repair in normal cells could be a factor for selectivity in photodynamic therapy. Our results obtained with leukemic cells are fully in agreement with data in the literature concerning similar experimental models.     

Synthesis and photobiological study of a novel chlorin photosensitizer BCPD-18MA for photodynamic therapy

This paper reports synthesis and photobiological properties of a novel chlorin photosensitizer BCPD-18MA. Cytotoxicity, cellular uptake, subcellular location, biodistribution, photodynamic therapy (PDT) efficiency, cell apoptosis as well as histological analysis of the liposomal-delivered BCPD-18MA (L-BCPD-18MA) was studied using mammary adenocarcinoma MDA-MB-231 cells and Lewis lung carcinoma (LLC) implanted in C57BL/6 mice as experimental models. The results showed that L-BCPD-18 was incorporated rapidly into MDA-MB-231 cells and localized partially in mitochondria. L-BCPD-18 induced cell apoptosis by PDT. In addition, biodistribution of L-BCPD-18MA in LLC-bearing mice demonstrated a fast clearance rate of the drug and good skin-related tumor selectivity. Finally, entrapment of BCPD-18 into liposomes resulted in a dramatic impairment of dark toxicity and a notable improvement of PDT antitumor efficacy in vitro. Compared with liposomal-delivered BPDMA (L-BPDMA), L-BCPD-18MA exhibited low dark toxicity and high PDT efficiency on MDA-MB-231 cells. The photodynamic efficacy of L-BCPD-18MA on LLC-bearing mice is comparable to that of L-BPDMA, implying that L-BCPD-18MA is a potential antitumor candidate for PDT.     

Development of a new photosensitizer on the basis of ytterbium porphyrazine complex

The tetraphenyltetracyanoporphyrazine complex of ytterbium has been studied as a potential photosensitizer for fluorescence diagnostics and photodynamic therapy (PDT) of cancer. It has been shown that the new compound has an intensive absorption and fluorescence in the "tissue optical window". In particular, the absorption maximum of the complex is at the wavelength of 590 nm, and the fluorescence emission maximum is at 640 nm. A strong fluorescence enhancement with a 50-fold increase in the quantum yield has been revealed in blood serum. The experiments on human cancer cells line have demonstrated that the complex penetrates the cells in vitro and is located around the nuclei. The biodistribution and pharmacokinetics of the complex in animals have been investigated in vivo by a new method of transillumination fluorescence imaging using a peculiar setup. It has been found that the period of maximum uptake of the complex in mouse cervical carcinoma is from 3 to 6 h after i.v. injection, with the half-life in the tumor being 24 h. However, the selectivity of the complex in the tumor is not high enough. The time of clearance from the body is about 48 h. The area of the strongest fluorescence in the abdominal cavity in in vivo images is anatomically recognized as the intestine. This indicates that the new compounds undergo mainly the hepatic clearance mainly. The conventional methods ex vivo (confocal microscopy and point spectroscopic measurements) have detected the largest content of the complex in the intestine, liver, skin and tumor tissue. In general, the optical characteristics of the ytterbium porphyrazine complex as well as the features of its interaction with biological objects make it promising drug candidate for the photodynamic therapy and/or fluorescence diagnostics of cancer. However, a search for other novel formulations possessing a higher tumor selectivity remains an urgent problem.     

Antileukemic effect of coral-prostanoids clavulones from the stolonifer Clavularia viridis on human myeloid leukemia (HL-60) cells

To elucidate the biological activities of coral-prostanoids, clavulones, discovered from the Japanese stolonifer Clavularia viridis, we examined the effect of clavulone on the cell growth of human cancer (human promyelocytic leukemia (HL-60) cells and HeLa cells) and normal (Chang liver cells and lung fibroblasts) cells in vitro. Clavulone showed strong antiproliferative and cytotoxic activities in the human cells and it had some selectivity to leukemic (HL-60) cells over other HeLa cells or normal cells on the basis of the IC50 values and cytotoxic effect of the cells. The IC50 value of clavulone in the HL-60 cells was about 0.4 microM (0.2 micrograms/ml). Over 1.0 microM (0.5 micrograms/ml), clavulone showed a significant cytotoxic activity on the HL-60 cells. The data on DNA synthesis and flow cytometric analysis revealed that clavulone arrests the cells in the G1-phase and inhibits the cell growth of HL-60 cells by inhibiting S-phase DNA synthesis. These results suggest that clavulone has a potent antileukemic effect on HL-60 cells.     

Synergistic anti-tumor effects of combination of photodynamic therapy and arsenic compound in cervical cancer cells: in vivo and in vitro studies

The effects of As(4)O(6) as adjuvant on photodynamic therapy (PDT) were studied. As(4)O(6) is considered to have anticancer activity via several biological actions, such as free radical production and inhibition of VEGF expression. PDT or As(4)O(6) significantly inhibited TC-1 cell proliferation in a dose-dependent manner (P<0.05) by MTT assay. The anti-proliferative effect of the combination treatment was significantly higher than in TC-1 cells treated with either photodynamic therapy or As(4)O(6) alone (62.4 and 52.5% decrease compared to vehicle-only treated TC-1 cells, respectively, P<0.05). In addition, cell proliferation in combination of photodynamic therapy and As(4)O(6) treatment significantly decreased by 77.4% (P<0.05). Cell survival pathway (Naip1, Tert and Aip1) and p53-dependent pathway (Bax, p21(Cip1), Fas, Gadd45, IGFBP-3 and Mdm-2) were markedly increased by combination treatment of photodynamic therapy and As(4)O(6). In addition, the immune response in the NEAT pathway (Ly-12, CD178 and IL-2) was also modulated after combination treatment, suggesting improved antitumor effects by controlling unwanted growth-stimulatory pathways. The combination effect apparently reflected concordance with in vitro data, in restricting tumor growth in vivo and in relation to some common signaling pathways to those observed in vitro. These findings suggest the benefit of combinatory treatment with photodynamic therapy and As(4)O(6) for inhibition of cervical cancer cell growth.     

Do folate-receptor targeted liposomal photosensitizers enhance photodynamic therapy selectivity?

One of the current goals in photodynamic therapy research is to enhance the selective targeting of tumor cells in order to minimize the risk and the extension of unwanted side-effects caused by normal cell damage. Special attention is given to receptor mediated delivery systems, in particular, to those targeted to folate receptor. Incorporation of a model photosensitizer (ZnTPP) into a folate-targeted liposomal formulation has been shown to lead an uptake by HeLa cells (folate receptor positive cells) 2-fold higher than the non-targeted formulation. As a result, the photocytotoxicity induced by folate-targeted liposomes was improved. This selectivity was completely inhibited with an excess of folic acid present in the cell culture media. Moreover, A549 cells (folate receptor deficient cells) have not shown variations in the liposomal incorporation. Nevertheless, the differences observed were slighter than expected. Both folate-targeted and non-targeted liposomes localize in acidic lysosomes, which confirms that the non-specific adsorptive pathway is also involved. These results are consistent with the singlet oxygen kinetics measured in living cells treated with both liposomal formulations.     

Intracellular photodynamic therapy with photosensitizer-nanoparticle conjugates: cancer therapy using a 'Trojan horse'.

Phthalocyanine-nanoparticle conjugates have been designed and synthesised for the delivery of hydrophobic photosensitizers for photodynamic therapy (PDT) of cancer. The phthalocyanine photosensitizer stabilized gold nanoparticles have an average diameter of 2-4 nm. The synthetic strategy interdigitates a phase transfer reagent between phthalocyanine molecules on the particle surface that solubilises the hydrophobic photosensitizer in polar solvents enabling delivery of the nanoparticle conjugates to cells. The phthalocyanine is present in the monomeric form on the nanoparticle surface, absorbs radiation maximally at 695 nm and catalytically produces the cytotoxic species singlet oxygen with high efficiency. These properties suggest that the phthalocyanine-nanoparticle conjugates are ideally suited for PDT. In a process that can be considered as cancer therapy using a 'Trojan horse', when the nanoparticle conjugates are incubated with HeLa cells (a cervical cancer cell line), they are taken up thus delivering the phthalocyanine photosensitizer directly into the cell interior. Irradiation of the nanoparticle conjugates within the HeLa cells induced substantial cell mortality through the photodynamic production of singlet oxygen. The PDT efficiency of the nanoparticle conjugates, determined using colorimetric assay, was twice that obtained using the free phthalocyanine derivative. Following PDT with the nanoparticle conjugates, morphological changes to the HeLa cellular structure were indicative of cell mortality via apoptosis. Further evidence of apoptosis was provided through the bioluminescent assay detection of caspase 3/7. Our results suggest that gold nanoparticle conjugates are an excellent vehicle for the delivery of surface bound hydrophobic photosensitizers for efficacious photodynamic therapy of cultured tumour cells.     

Targeting tumor cells through chitosan-folate modified microcapsules loaded with camptothecin

Poly(vinyl alcohol) microcapsules have been tailored as carriers to deliver camptothecin, an anticancer drug poorly soluble in water. The capsules have been reacted with a chitosan--folate complex in order to selectively target cancer cells overexpressing the folic acid receptor. Microcapsules decorated with the chitosan--folate complex have been characterized in their uptake and release of camptothecin, following the absorption band at λ = 370 nm diagnostic of the drug molecule. The selectivity of chitosan-folate microcapsules in targeting cancer cells has been demonstrated by fluorescence microscopy using HeLa cells, overexpressing the folate receptor and NIH3t3 fibroblasts as a negative control. The chitosan--folate microcapsules loaded with camptothecin significantly reduce the proliferation of HeLa tumor cells, while they have a negligible effect on fibroblasts. This work demonstrates that the chitosan--folate microcapsules represent a promising system to selectively target hydrophobic drugs, such as camptothecin, to tumor cells.     

Dual-targeting multifunctional hyaluronic acid ligand-capped gold nanorods with enhanced endo-lysosomal escape ability for synergetic photodynamic–photothermal therapy of cancer

Au nanorods (AuNRs) have attracted considerable interest as drug delivery systems because of their enhanced cell internalization and stronger drug-loading ability. In addition, the incorporation of photodynamic therapy (PDT) and photothermal therapy (PTT) into one nanosystem presents great promise to defect multiple drawbacks in cancer therapy. Herein, we fabricated a multifunctional and dual-targeting nanoplatform based on hyaluronic acid-grafted-(mPEG/triethylenetetramine-conjugated-lipoic acid/tetra(4-carboxyphenyl)porphyrin/folic acid) polymer ligand capped AuNRs (AuNRs@HA-g-(mPEG/Teta-co-(LA/TCPP/FA)) for combined photodynamic–photothermal therapy of cancer. The prepared nanoparticles displayed high TCPP loading capacity and excellent stability in different biological media. Furthermore, AuNRs@HA-g-(mPEG/Teta-co-(LA/TCPP/FA)) not only could produce a localized hyperthermia to conduct PTT, but also generate cytotoxic singlet oxygen (¹O₂) to perform PDT under laser irradiation. Confocal imaging results disclosed that this nanoparticle endowing the specific function of polymeric ligand could enhance cellular uptake, accelerate endo/lysosomal escape, as well as produce higher reactive oxygen species. Importantly, this combination therapy strategy could also induce higher anticancer potential than PDT or PTT only against MCF-7 tumor cells in vitro. Therefore, this work presented an AuNRs-based therapeutic nanoplatform with great potential in dual-targeting and photo-induced combination therapy of cancer.     

Apoptosis photoinduction by C60 fullerene in human leukemic T cells

The viability of normal (Wistar rat thymocytes) and transformed (human leukemia Jurkat cells) T cells after UV/Vis irradiation in the presence of pristine C60 fullerene was studied. The data obtained have shown that C60 fullerene exhibits cytotoxic effect against transformed T lymphocytes when combined with UV/Vis irradiation using mercury-vapor lamp (320-600 nm). C60 fullerene photocytotoxicity was not detected in thymocytes. C60-dependent photoinduced apoptosis of Jurkat cells was confirmed by DNA fragmentation and caspase-3 activation. No substantial increase of caspase-3 activation was observed in thymocytes treated with C60 fullerene plus irradiation, while antileukemic agent cytosine arabinoside was shown to induce caspase-3 activation both in Jurkat cells and thymocytes. The data obtained may be useful for development of photosensitizers for photodynamic therapy with selective action on leukemia cells.     

Eriodictyol mediated selective targeting of the TNFR1/FADD/TRADD axis in cancer cells induce apoptosis and inhibit tumor progression and metastasis

While the anti-inflammatory activities of Eriodictyol, a plant-derived flavonoid is well-known, reports on its anti-cancer efficacy and selective cytotoxicity in cancer cells are still emerging. However, little is known regarding its mechanism of selective anti-cancer activities. Here, we show the mechanism of selective cytotoxicity of Eriodictyol towards cancer cells compared to normal cells. Investigation reveals that Eriodictyol significantly upregulates TNFR1 expression in tumor cells (HeLa and SK-RC-45) while sparing the normal cells (HEK, NKE and WI-38), which display negligible TNFR1 expression, irrespective of the absence or presence of Eriodictyol. Further investigation of the molecular events reveal that Eriodictyol induces apoptosis through expression of the pro-apoptotic DISC components leading to activation of the caspase cascade. In addition, CRISPR-Cas9 mediated knockout of TNFR1 completely blocks apoptosis in HeLa cells in response to Eriodictyol, confirming that Eriodictyol induced cancer cell apoptosis is indeed TNFR1-dependent. Finally, in vivo data demonstrates that Eriodictyol not only impedes tumor growth and progression, but also inhibits metastasis in mice implanted with 4T1 breast cancer cells. Thus, our study has identified Eriodictyol as a compound with high selectivity towards cancer cells through TNFR1 and suggests that it can be further explored for its prospect in cancer therapeutics.     

A novel approach to a bifunctional photosensitizer for tumor imaging and phototherapy

Optical imaging has attracted a great attention for studying molecular recognitions because minute fluorescent tracers can be detected in homogeneous and heterogeneous media with existing laboratory instruments. In our preliminary study, a clinically relevant photosensitizer (HPPH, a chlorophyll-a analog) was linked with a cyanine dye (with required photophysical characteristics but limited tumor selectivity), and the resulting conjugate was found to be an efficient tumor imaging (fluorescence imaging) and photosensitizing agent. Compared to HPPH, the presence of the cyanine dye moiety in the conjugate produced a significantly higher uptake in tumor than skin. At a therapeutic/imaging dose, the conjugate did not show any significant skin phototoxicity, a major drawback associated with most of the porphyrin-based photosensitizers. These results suggest that tumor-avid porphyrin-based compounds can be used as "vehicles" to deliver the desired fluorescent agent(s) to tumor. The development of tumor imaging or improved photodynamic therapy agent(s) by itself represents an important step, but a dual function agent (fluorescence imaging and photodynamic therapy) provides the potential for tumor detection and targeted photodynamic therapy, combining two modalities into a single cost-effective "see and treat" approach.     

Photodynamic effects of a novel pterin derivative on a pancreatic cancer cell line

6-Formylpterin (6FP) has the potential to produce singlet oxygen (1O2) under UV-A radiation. In order to apply this potential to anti-cancer photodynamic therapy (PDT), we prepared a novel variant of 6FP, 2-(N,N-dimethylaminomethyleneamino)-6-formyl-3-pivaloylpteridine-4-one (6FP-tBu-DMF), and examined its photodynamic effects on a pancreatic cancer cell line, Panc-1 cells. The study using laser scanning confocal microscopy showed that the drug uptake, the 1O2 generation, and cell death were observed in the 6FP-tBu-DMF-treated cells, while these phenomena were not observed in the 6FP-treated cells. The MTT assay also showed the decrease in cell viability only in the 6FP-tBu-DMF-treated cells. Since 6FP and 6FP-tBu-DMF generate 1O2 to the same extent under UV-A radiation in aqueous solutions, these results indicated that the differences in the photodynamic effects between 6FP and 6FP-tBu-DMF were entirely attributed to the differences in the cell permeability between them. The development of cell permeable pterin derivatives has the potential for application in PDT.     

C_(60)对小鼠S_(180)肉瘤光动力学作用模型的建立

为验证Ｃ６０对活体肿瘤的光动力学损伤作用,我们从两方面进行实验：Ｃ６０对荷瘤小鼠的Ｓ１８０实体瘤的光动力学杀伤作用和Ｃ８０对离体Ｓ１８０肿瘤细胞的光动力学杀伤作用,在小鼠的瘤体上注射Ｃ８０光敏剂,在５１１ｎｍ、５７８ｎｍ混合黄录色激光照射正派主发Ｃ６０,产生大量的单线态氧,杀伤活性肿瘤。激光光强为５００ｍＷ,Ｃ６０浓度为３０μｇ／ｍｌ时,荷瘤小鼠寿命平均延长５天,瘤径减小１ｃｍ,瘤重减轻０．８克,     

Effects of hyperthermia and photodynamic therapy on BALB/c mice bearing subcutaneous tumors

The therapeutic effects of photodynamic therapy and hyperthermia on mice bearing subcutaneous tumors were investigated. Ehrlich ascites tumor cells (1 x 10(7)) were implanted subcutaneously into the femoral area of BALB/c mice. A total of 134 tumor-bearing mice were treated with photodynamic therapy, i.e., administration of laser irradiation (514.5 nm, 112.5 mW/cm2 for 11.12 min with a total energy 75 J/cm2) after injection (i.p.) of hematoporphyrin derivative (HPD, 7.5 and 10.0 mg/kg body weight) and/or hyperthermia (by electric heating needles to 44 and 45 degrees C for 30 min) once a day for three successive days. The results revealed that the therapeutic effects of the combination of photodynamic therapy and hyperthermia were improved when compared with photodynamic therapy or hyperthermia alone. A combination of photodynamic therapy (10.0 mg HPD/kg body weight and 75 J/cm2 of total laser irradiation energy) and hyperthermia (44 degrees C for 30 min) had the best therapeutic effect, indicating that the mortality rate within 120 days (MR120) was 12.5% and the mean survival time (MST120) was 113.8 days.     

Effect of curcumin-nanoemulsion associated with photodynamic therapy in breast adenocarcinoma cell line

Curcumin, a natural compound has several antineoplastic activities and is a promising natural photosensitizer used in photodynamic therapy. However, its low solubility in physiological medium limit the clinical use of curcumin. This study aimed to analyze the action of curcumin-nanoemulsion, a new and well-designed Drug Delivery System (DDS+) molecule, used as a photosensitizing agent in photodynamic therapy in an in vitro breast cancer model, MCF-7 cells. The empty nanoemulsion fulfils all necessary requirements to be an excellent DDS. Furthermore, the use of curcumin-nanoemulsion in photodynamic therapy resulted in a high phototoxic effect after activation at 440?nm, decreasing to <10% viable tumor cells after two irradiations and increasing the reactive oxygen species (ROS) production. The use of curcumin-nanoemulsion associated with photodynamic therapy resulted in an increase in the levels of caspase 3/7 activity for the studied MCF-7 cell model, indicating that this therapy triggers a cascade of events that lead to cell death, such as cellular apoptosis. In conclusion, curcumin-nanoemulsion proved to be efficient as a photosensitizing agent, had phototoxic effects, significantly decreased the proliferation of MCF-7 cells and stimulating the ROS production in combination with photodynamic therapy, so, this formulation has a great potential for use in treatment of breast cancer.