Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm). Under blue light irradiation at 3.744J/cm(2) (=0.52mW/cm(2) irradiated for 2h), the minimal lethal dose is 3.125μM and the median lethal doses (LD50) for FMN and FAD are 6.5μM and 7.2μM, respectively. Individual exposure to visible blue light irradiation or riboflavin photosensitizers does not produce cytotoxicity and no side effects are observed in this study. The western blotting results also show that an intrinsic apoptosis pathway is activated by the ROS during photolysis of riboflavin analogues. Blue light triggers the cytotoxicity of riboflavins on HeLa cells in vitro. Based on these results, this is a feasible and efficient of PDT with an intrinsic photosensitizer for cancer research.

This study assessed the effect of curcumin as a photosensitizer in antimicrobial photodynamic therapy (aPDT) for the treatment of induced periodontitis in rats. Periodontitis was induced via a ligature around the mandibular first molar on the left side of 96 rats. The ligature was removed 7 days later, and the animals were randomized into four groups: NT, no local treatment; CUR, irrigation with curcumin solution (40 μM); LED, irradiation with a light-emitting diode (LED, InGaN, 465-485 nm, 200 mW/cm(2), 60 s); and aPDT, irrigation with curcumin solution (40 μM) followed by irradiation with LED. Eight animals from each group were euthanized at 7, 15, and 30 days post-treatment. Treatments were assessed using alveolar bone loss (ABL) in the furcation region using histological, histometric, and immunohistochemical analyses. Rats treated with aPDT exhibited less ABL at 7 days compared to the NT group, moderate pattern immunolabeling for osteoprotegerin at 30 days, and a pattern of immunolabeling for RANKL from moderate to low. Treatments resulted in smaller numbers of TRAP-positive cells compared to the NT group. aPDT as monotherapy using curcumin as a photosensitizer and LED as the light source was effective in the treatment of induced periodontitis in rats.

Photodynamic therapy is widely used in the clinical treatment of tumors, especially skin cancers. It has been reported that the photosensitizer curcumin, in combination with ultraviolet radiation B, induces HaCaT cell apoptosis, and this effect may be due to the activation of caspase pathways. In this study, we examined the photodynamic effects of demethoxycurcumin, a more stable analogue of curcumin, to determine whether it could induce apoptosis in skin cancer cells. We investigated the effects of a combination of ultraviolet radiation B and demethoxycurcumin on apoptotic cell death in A431 and HaCaT cells and determined the molecular mechanism of action. Our results showed increased apoptosis with a combination of ultraviolet radiation B with demethoxycurcumin, as compared to ultraviolet radiation B or demethoxycurcumin alone. The combination of ultraviolet radiation B irradiation with demethoxycurcumin synergistically induced apoptotic cell death in A431 and HaCaT cells through activation of p53 and caspase pathways, as well as through upregulation of Bax and p-p65 expression and downregulation of Bcl-2, Mcl-1, and nuclear factor-κB expression. In addition, we found that reactive oxygen species significantly increased with treatment, and mitochondrial membrane potential depolarization was remarkably enhanced. In conclusion, our data indicate that demethoxycurcumin may be a promising photosensitizer for use in photodynamic therapy to induce apoptosis in skin cancer cells.

Photodynamic therapy is widely used in the clinical treatment of tumors, especially skin cancers. It has been reported that the photosensitizer curcumin, in combination with ultraviolet radiation B, induces HaCaT cell apoptosis, and this effect may be due to the activation of caspase pathways. In this study, we examined the photodynamic effects of demethoxycurcumin, a more stable analogue of curcumin, to determine whether it could induce apoptosis in skin cancer cells. We investigated the effects of a combination of ultraviolet radiation B and demethoxycurcumin on apoptotic cell death in A431 and HaCaT cells and determined the molecular mechanism of action. Our results showed increased apoptosis with a combination of ultraviolet radiation B with demethoxycurcumin, as compared to ultraviolet radiation B or demethoxycurcumin alone. The combination of ultraviolet radiation B irradiation with demethoxycurcumin synergistically induced apoptotic cell death in A431 and HaCaT cells through activation of p53 and caspase pathways, as well as through upregulation of Bax and p-p65 expression and downregulation of Bcl-2, Mcl-1, and nuclear factor-κB expression. In addition, we found that reactive oxygen species significantly increased with treatment, and mitochondrial membrane potential depolarization was remarkably enhanced. In conclusion, our data indicate that demethoxycurcumin may be a promising photosensitizer for use in photodynamic therapy to induce apoptosis in skin cancer cells.

Photodynamic therapy (PDT), as a clinical cancer therapy, is a mild therapy, which involves application of photosensitizers (PSs) which located in target cells and then be irradiated by corresponding wawelength. The activation of PSs generates radical oxygenspecies ( ROS) to exert a selective cytotoxic activity for the target cells. Aloeemodin (AE) has been found to be a anti-tumor agent in many studies, and it also demonstrated to be a photosensitizer in recent years. In order to study the mechanism of aloe-emodin as a photosensitizer. In the present study, we investigated the mechanisms of photo-cytotoxicity induced by aloe-emodin in breast cancer MCF-7 cells. Analysis of cell proliferation evidenced that there was a dramatically depression after photodynamic treatment with aseries of aloe-emodin concentration and light doses showed. We observed changes apoptosis and demonstrated that the mechanisms of apoptosis were involved of mitochondrial and endoplasmic reticulum death pathway. The capacity of adhesion, migration and invasion of breast cells were measured usingWST8 and transwell assay and demonstrated that AE-PDT significantly inhibited adhesion, migration and invasion of MCF-7cells. The expression of MMP2, MMP9, VEGF and Nrf2 demonstrated that the metastasis was related to oxidative stress. Analysis of changes in cytoskeleton components (F-actin) evidenced cytoskeleton disorganization after treatment with AE-PDT. Taken together, the present results indicated that PDT with aloe emodin effectively suppressed cancer development in MCF-7cells, suggesting the potential of AE as one new photosensitizer in PDT can provide a new modility for treating cancer.

Photodynamic therapy (PDT), as a clinical cancer therapy, is a mild therapy, which involves application of photosensitizers (PSs) which located in target cells and then be irradiated by corresponding wawelength. The activation of PSs generates radical oxygenspecies ( ROS) to exert a selective cytotoxic activity for the target cells. Aloeemodin (AE) has been found to be a anti-tumor agent in many studies, and it also demonstrated to be a photosensitizer in recent years. In order to study the mechanism of aloe-emodin as a photosensitizer. In the present study, we investigated the mechanisms of photo-cytotoxicity induced by aloe-emodin in breast cancer MCF-7 cells. Analysis of cell proliferation evidenced that there was a dramatically depression after photodynamic treatment with aseries of aloe-emodin concentration and light doses showed. We observed changes apoptosis and demonstrated that the mechanisms of apoptosis were involved of mitochondrial and endoplasmic reticulum death pathway. The capacity of adhesion, migration and invasion of breast cells were measured usingWST8 and transwell assay and demonstrated that AE-PDT significantly inhibited adhesion, migration and invasion of MCF-7cells. The expression of MMP2, MMP9, VEGF and Nrf2 demonstrated that the metastasis was related to oxidative stress. Analysis of changes in cytoskeleton components (F-actin) evidenced cytoskeleton disorganization after treatment with AE-PDT. Taken together, the present results indicated that PDT with aloe emodin effectively suppressed cancer development in MCF-7cells, suggesting the potential of AE as one new photosensitizer in PDT can provide a new modility for treating cancer.

OBJECTIVES:Recently, photodynamic therapy (PDT) has been introduced as a new modality in oral bacterial decontamination. Current research aims to evaluate the effect of photodynamic killing of visible blue light in the presence of hydrogen peroxide, curcumin and erythrosine as potential oral photosensitizers on Porphyromonas gingivalis associated with periodontal bone loss and Fusobacterium nucleatum associated with soft tissue inflammation.

MATERIALS AND METHODS:Standard suspension of P. gingivalis and F. nucleatum were exposed to Light Emitting Diode (LED) (440-480 nm) in combination with erythrosine (22µm), curcumin (60 µM) and hydrogen peroxide (0.3 mM) for 5 min. Bacterial samples from each treatment groups (radiation-only group, photosensitizer-only group and blue light-activated photosensitizer group) were subcultured onto the surface of agar plates. Survival of these bacteria was determinedby counting the number of colony forming units (CFU) after incubation.

RESULTS:RESULTS for antibacterial assays on P. gingivalis confirmed that curcumin, Hydrogen peroxide and erythrosine alone exerted a moderate bactericidal effect which enhanced noticeably in conjugation with visible light. The survival rate of P. gingivalis reached zero present when the suspension exposed to blue light-activated curcumin and hydrogen peroxide for 2 min. Besides, curcumin exerted a remarkable antibacterial activity against F. nucleatum in comparison with erythrosine and hydrogen peroxide (P=0.00). Furthermore, the bactericidal effect of visible light alone on P. gingivalis as black-pigmented bacteria was significant.

CONCLUSION:Our result suggested that visible blue light in the presence of erythrosine, curcumin and hydrogen peroxide would be consider as a potential approach of PDT to kill the main gramnegative periodontal pathogens. From a clinical standpoint, this regimen could be established as an additional minimally invasive antibacterial treatment of plaque induced periodontal pathologies.

Melanoma is the most aggressive and lethal form of skin cancer, responsible for>80% of deaths. Standard treatments for late-stage melanoma usually present poor results, leading to life-threatening side effects and low overall survival. Thus, it is necessary to rethink treatment strategies and design new tools for the treatment of this disease. On that ground, we hereby report the use of acai oil in nanoemulsion (NanoA) as a novel photosensitizer for photodynamic therapy (PDT) used to treat melanoma in in vitro and in vivo experimental models. NIH/3T3 normal cells and B16F10 melanoma cell lines were treated with PDT and presented 85% cell death for melanoma cells, while maintaining high viability in normal cells. Flow cytometry indicated that cell death occurred by late apoptosis/necrosis. Tumor bearing C57BL/6 mice treated five times with PDT using acai oil in nanoemulsion showed tumor volume reduction of 82% in comparison to control/tumor group. Necrotic tissue per tumor area reached its highest value in PDT-treated mice, supporting PDT efficacy. Overall, acai oil in nanoemulsion was an effective photosensitizer, representing a promising source of new photosensitizing molecules for PDT treatment of melanoma, a tumor with an inherent tendency to be refractory for this type of therapy.

BACKGROUND:Chlorophyll-a is a novel photosensitizer recently tested for the treatment of acne vulgaris.

OBJECTIVE:We sought to evaluate the clinical efficacy and safety of chlorophyll-a photodynamic therapy used for acne treatment.

METHODS:Subjects with acne on both sides of the face were included. Eight treatment sessions were performed over a 4-week duration. Half of the face was irradiated using a blue and red light-emitting diode after topical application of chlorophyll-lipoid complex. The other half underwent only light-emitting diode phototherapy. The lesion counts and acne severity were assessed by a blinded examiner. Sebum secretion, safety, and histologic changes were also evaluated.

RESULTS:In total, 24 subjects completed the study. Facial acne improved on both treated sides. On the chlorophyll-a photodynamic therapy-treated side, there were significant reductions in acne lesion counts, acne severity grades, and sebum levels compared with the side treated with light-emitting diode phototherapy alone. The side effects were tolerable in all the cases.

LIMITATIONS:All the subjects were of Asian descent with darker skin types, which may limit the generalizability of the study. A chlorophyll-a arm alone is absent, as is a no-treatment arm.

CONCLUSIONS:We suggest that chlorophyll-a photodynamic therapy for the treatment of acne vulgaris can be effective and safe with minimal side effects.

BACKGROUND AND OBJECTIVES:Our group recently synthesized a new, low-cost photosensitizer, chlorophyllin f. In this study, the effects of chlorophyllin f-mediated photodynamic therapy (PDT) and its potential mechanisms were examined in human bladder cancer cells.

MATERIALS AND METHODS:MitoTracker® Green probe and LysoTracker® Green probe were used to label mitochondria and lysosomes, revealing the intracellular localization of chlorophyllin f in 5637 and T24 cells by confocal laser scanning microscopy (CLSM). The cells were treated with chlorophyllin f-mediated PDT; the photo-cytotoxicityof chlorophyllin f was monitored using the Cell Counting Kit-8 assay, and apoptosis was measured by Annexin V-FITC/PI dual staining. Western blotting, transmission electron microscopy (TEM), and staining with Cyto-ID® Autophagy Detection dye, monodansylcadaverine (MDC) and acridine orange were performed to assess autophagy. The role of autophagy was examined by measuring cell viability and apoptosis in both cell lines pretreated with the autophagy inhibitor 3-methyladenine (3-MA).

RESULTS:Chlorophyllin f showed affinity for mitochondria and lysosomes. It exhibited significant photocytotoxicity, resulting in a maximum of 86.51% and 84.88% cell death in 5637 and T24 cells, respectively. Additionally, chlorophyllin f-mediated PDT (f-PDT) also induced a significantly higher percentage of apoptosis in treated cells compared to the control groups (P < 0.05). Moreover, the expression of Beclin1 protein and the proportion of LC3-II:LC3-I in both cell lines significantly increased after f-PDT. Autophagy, characterized by an increase in the formation of Cyto-ID® Autophagy Detection dye-labeled autophagosomes, MDC fluorescent dye-labeled autophagic vacuoles and acridine orange-labeled acidic vesicular organelles (AVOs), was observed in f-PDT-treated cells. TEM also revealed double-membrane autophagosome structures 1 hour after f-PDT. Most importantly, when pretreated with 3-MA, the two cell lines showed more significant photo-cytotoxicityand apoptotic cell death compared to those exposed to f-PDT alone (P < 0.05).

CONCLUSION:Chlorophyllin f-mediated PDT exerts anti-tumor activity by inducing apoptosis and autophagy, and most importantly, autophagy inhibition enhances f-PDT-mediated apoptotic cell death. These results suggest that chlorophyllin f is a new, effective photosensitizer and that the combination of f-PDT with autophagy inhibitors may be an attractive therapeutic strategy against human non-muscle invasive bladder cancer.

Curcumin is a yellow-orange compound derived from the root of Curcuma longa (Zingiberaceae family), that has been used as a medicine, spice and coloring agent. Curcumin has proved nontoxic in a number of cell culture and whole animal studies. Curcumin has, however, been reported to have bactericidal effects at very high concentrations. When illuminated, curcumin exerted potent phototoxic effects in micromolar amounts. Gram-negative bacteria displayed greater resistance to curcumin phototoxicity relative to Gram-positive bacteria. Oxygen was required for curcumin phototoxicity. Curcumin binding to cells was not required for photokilling; the reactive intermediate therefore must be relatively long-lived. The mechanism(s) of curcumin phototoxicity may involve hydrogen peroxide production. Singlet excited oxygen was not detected.