Self-assembled polymeric micelles for targeted photodynamic therapy of human epidermal growth factor receptor 2 overexpressing breast cancer.

Photodynamic therapy (PDT) has been extensively explored as a promising alternative therapeutic approach for many malignant tumors. However, the PDT system generally involves unsatisfactory tumor specificity and nonspecific accumulation of photosensitizers around the target cancer cells, leading to phototoxic damage to adjacent healthy normal cells. In this study, we developed pheophorbide a (Pheo a)/human epidermal growth factor receptor 2 (HER2) targeting peptide (epitope form, HLTV, PEG2-LTVSPWY)-co-conjugated methoxy poly(ethylene glycol)-block-poly(L-lysine hydrochloride) (PEG-PLL)/hyaluronic acid (HA) (P3H2) polymeric micelles via a self-assembly method for HER2-targeted PDT treatment for breast cancer, thereby enhancing the PDT efficacy. The synthesized P3H2 polymeric micelles were spherical, with an average diameter of 125.7 ± 21.2 nm in an aqueous solution. The results ofin vitrocytotoxicity assays demonstrated that the P3H2 polymeric micelles significantly improved PDT efficacy on the SK-BR-3 cells due to the enhanced targeting ability. In addition, PDT treatment using the P3H2 polymeric micelles effectively killed breast cancer cells by inducing higher intracellular reactive oxygen species generation and apoptotic cell death. In particular, the three-dimensional cell culture model proved the synergistic PDT efficacy using P3H2 polymeric micelles on the SK-BR-3 cells. Based on these results, the PDT treatment using P3H2 polymeric micelles can serve as a highly effective therapeutic modality for breast cancer.

Effects of Ethanol Extracts from Grateloupia elliptica, a Red Seaweed, and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression.

Grateloupia elliptica (G. elliptica) is a red seaweed with antioxidant, antidiabetic, anticancer, anti-inflammatory, and anticoagulant activities. However, the anti-obesity activity of G. elliptica has not been fully investigated. Therefore, the effect of G. elliptica ethanol extract on the suppression of intracellular lipid accumulation in 3T3-L1 cells by Oil Red O staining (ORO) was evaluated. Among the eight red seaweeds tested, G. elliptica 60% ethanol extract (GEE) exhibited the highest inhibition of lipid accumulation. GEE was the only extract to successfully suppress lipid accumulation among ethanol extracts from eight red seaweeds. In this study, we successfully isolated chlorophyll derivative (CD) from the ethyl acetate fraction (EA) of GEE by high-performance liquid chromatography and evaluated their inhibitory effect on intracellular lipid accumulation in 3T3-L1 adipocytes. CD significantly suppressed intracellular lipid accumulation. In addition, CD suppressed adipogenic protein expression such as sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid binding protein 4 (FABP4). Taken together, our results indicate that CD from GEE inhibits lipid accumulation by suppressing adipogenesis via the downregulation of adipogenic protein expressions in the differentiated adipocytes. Therefore, chlorophyll from G. elliptica has a beneficial effect on lipid metabolism and it could be utilized as a potential therapeutic agent for preventing obesity.

Phytol, a Chlorophyll Component, Produces Antihyperalgesic, Anti-inflammatory, and Antiarthritic Effects: Possible NFκB Pathway Involvement and Reduced Levels of the Proinflammatory Cytokines TNF-α and IL-6.

Phytol is a diterpene constituent of chlorophyll and has been shown to have several pharmacological properties, particularly in relation to the management of painful inflammatory diseases. Arthritis is one of the most common of these inflammatory diseases, mainly affecting the synovial membrane, cartilage, and bone in joints. Proinflammatory cytokines, such as TNF-α and IL-6, and the NFκB signaling pathway play a pivotal role in arthritis. However, as the mechanisms of action of phytol and its ability to reduce the levels of these cytokines are poorly understood, we decided to investigate its pharmacological effects using a mouse model of complete Freund's adjuvant (CFA)-induced arthritis. Our results showed that phytol was able to inhibit joint swelling and hyperalgesia throughout the whole treatment period. Moreover, phytol reduced myeloperoxidase (MPO) activity and proinflammatory cytokine release in synovial fluid and decreased IL-6 production as well as the COX-2 immunocontent in the spinal cord. It also downregulated the p38MAPK and NFκB signaling pathways. Therefore, our findings demonstrated that phytol can be an innovative antiarthritic agent due to its capacity to attenuate inflammatory reactions in joints and the spinal cord, mainly through the modulation of mediators that are key to the establishment of arthritic pain.

Self-Amplified Photodynamic Therapy through the 1 O2 -Mediated Internalization of Photosensitizers from a Ppa-Bearing Block Copolymer.

Nanocarriers are employed to deliver photosensitizers for photodynamic therapy (PDT) through the enhanced penetration and retention effect, but disadvantages including the premature leakage and non-selective release of photosensitizers still exist. Herein, we report a 1 O2 -responsive block copolymer (POEGMA-b-P(MAA-co-VSPpaMA) to enhance PDT via the controllable release of photosensitizers. Once nanoparticles formed by the block copolymer have accumulated in a tumor and have been taken up by cancer cells, pyropheophorbide a (Ppa) could be controllably released by singlet oxygen (1 O2 ) generated by light irradiation, enhancing the photosensitization. This was demonstrated by confocal laser scanning microscopy and in vivo fluorescence imaging. The 1 O2 -responsiveness of POEGMA-b-P(MAA-co-VSPpaMA) block copolymer enabled the realization of self-amplified photodynamic therapy by the regulation of Ppa release using NIR illumination. This may provide a new insight into the design of precise PDT.

Fabrication of a Dual-Stimuli-Responsive Supramolecular Micelle from a Pillar[5]arene-Based Supramolecular Diblock Copolymer for Photodynamic Therapy.

A pH and thermo dual-responsive supramolecular diblock copolymer is constructed by host-guest recognition of pillar[5]arene and viologen salt. The host polymer, poly(N,N-dimethylaminoethyl methacrylate) bearing pillar[5]arene as the terminal group (P[5]A-PDMAEMA) is synthesized by atom transfer radical polymerization (ATRP). Guest polymer, ethyl viologen-ended poly(N-isopropylacrylamide) (EV-PNIPAM) is prepared by reversible addition-fragmentation chain transfer polymerization. The supramolecular diblock copolymer can be self-assembled into stable supramolecular nanoparticles in aqueous solution at 40 °C, which show excellent pH and thermo responsiveness. The nanoparticles are further applied in the encapsulation of photosensitizers (pyropheophorbide-a, PhA) for photodynamic therapy (PDT). The dual-responsive nanoparticles can efficiently release PhA in acidic environment at 25 °C. Based on the result of cell experiments, PhA-loaded nanomicelles exhibit excellent PDT efficacy and low dark toxicity toward A549 cells. Thus, this supramolecular diblock copolymer enriches the methodology of constructing stimuli-responsive drug carriers and presents a great potential in PDT.

Folate-modified PLGA nanoparticles for tumor-targeted delivery of pheophorbide a in vivo.

Targeted drug delivery has been an important issue for tumor therapy including photodynamic therapy (PDT). The purpose of our study is to increase the targeting efficiency of photosensitizer (PS) using folate-modified nanoparticles (NPs) to tumor site in vivo. Folate receptor is over-expressed on the surface of many human cancer cells. We prepared poly (lactic-co-glycolic acid) (PLGA) NPs containing pheophorbide a (Pba), a PS that is used in PDT and generates free radical for killing cancer cells. The surface of NPs was composed of phospholipids modified with polyethylene glycol (PEG) and folate (FA). The size of the resulting FA-PLGA-Pba NPs was about 200 nm in PBS at pH 7.4 and they were stable for long time. They showed faster cellular uptake to MKN28 human gastric cancer cell line than control PLGA-Pba NPs by high-affinity binding with folate receptors on cell surface. In MTT assay, FA-PLGA-Pba NPs also showed enhanced tumor cell killing compared to control PLGA-Pba NPs. In vivo and ex vivo imaging showed high accumulation of FA-PLGA-Pba NPs in tumor site during 24 h after intravenous injection to MKN28 tumor-bearing mice model. These results demonstrate that our FA-PLGA-Pba NPs are useful for tumor-targeted delivery of PS for cancer treatment by PDT.

Tuning Pharmacokinetics to Improve Tumor Accumulation of a Prostate-Specific Membrane Antigen-Targeted Phototheranostic Agent.

We describe a simple and effective bioconjugation strategy to extend the plasma circulation of a low molecular weight targeted phototheranostic agent, which achieves high tumor accumulation (9.74 ± 2.26%ID/g) and high tumor-to-background ratio (10:1). Long-circulating pyropheophorbide (LC-Pyro) was synthesized with three functional building blocks: (1) a porphyrin photosensitizer for positron-emission tomography (PET)/fluorescence imaging and photodynamic therapy (PDT), (2) a urea-based prostate-specific membrane antigen (PSMA) targeting ligand, and (3) a peptide linker to prolong the plasma circulation time. With porphyrin's copper-64 chelating and optical properties, LC-Pyro demonstrated its dual-modality (fluorescence/PET) imaging potential for selective and quantitative tumor detection in subcutaneous, orthotopic, and metastatic murine models. The peptide linker in LC-Pyro prolonged its plasma circulation time about 8.5 times compared to its truncated analog. High tumor accumulation of LC-Pyro enabled potent PDT, which resulted in significantly delayed tumor growth in a subcutaneous xenograft model. This approach can be applied to improve the pharmacokinetics of existing and future targeted PDT agents for enhanced tumor accumulation and treatment efficacy.

Marine natural pigments as potential sources for therapeutic applications.

In recent years, marine natural pigments have emerged as a powerful alternative in the various fields of food, cosmetic, and pharmaceutical industries because of their excellent biocompatibility, bioavailability, safety, and stability. Marine organisms are recognized as a rich source of natural pigments such as chlorophylls, carotenoids, and phycobiliproteins. Numerous studies have shown that marine natural pigments have considerable medicinal potential and promising applications in human health. In this review, we summarize the marine natural pigments as potential sources for therapeutic applications, including: antioxidant, anticancer, antiangiogenic, anti-obesity, anti-inflammatory activities, drug delivery, photothermal therapy (PTT), photodynamic therapy (PDT), photoacoustic imaging (PAI), and wound healing. Marine natural pigments will offer a better platform for future theranostic applications.

Photodynamic therapy of human lung cancer xenografts in mice.

BACKGROUND: There is a need to develop novel therapies for non-small cell lung cancer (NSCLC). Photodynamic therapy has been used successfully for endobronchial palliation of NSCLC, and its role in early stages of disease is being explored. We hypothesized that a novel photosensitizer, PS1, would be more effective than the standard agent, porfimer sodium (Photofrin or PFII), in treating human lung cancer xenografts in mice. MATERIALS AND METHODS: Patient-derived NSCLC xenografts were established subcutaneously in severe combined immune deficiency mice. Two groups of five mice were injected with PS1 (3-[1'-m-iodobenzyloxy]ethyl-3-devinylpyropheophorbide-a), a chlorophyll-a derivative, or PFII (a purified version of hematoporphyrin derivative) and then treated with nonthermal laser light. Four mice were treated with laser light without photosensitizer and six mice received no treatment at all. All mice were then observed for tumor growth. The tumor growth end point, time-to-1000 mm(3), was evaluated using standard Kaplan-Meier methods and the log-rank test. Tumor hematoxylin and eosin and caspase 3 staining was done to evaluate necrosis and apoptosis. RESULTS: The median time-to-1000 mm(3) was 12, 12, 26, and 52 d for the control, light only, PFII, and PS1 groups. There was a significant association between the tumor growth end point and treatment (P < 0.05). Hematoxylin and eosin staining revealed <1%, 0%, 67%, and 80% necrosis, and caspase 3 positivity was 2%, <1%, 17%, and 39%, respectively, in the same four groups. CONCLUSIONS: The mice treated with PS1 exhibited a longer time for tumor regrowth and showed more tumor necrosis and apoptosis compared with the other treatment groups. Thus, the novel photosensitizer, PS1, was demonstrated to be more effective than porfimer sodium in this preclinical pilot study.

Effects of sodium ferrous chlorophyll treatment on anemia of hemodialysis patients and relevant biochemical parameters.

This study explores the effects of sodium ferrous chlorophyll treatment on the anemia of maintenance hemodialysis (MHD) patients, as well as the relevant biochemical parameters. We selected 72 patients who had received regular MHD treatment two or three times a week for more than 3 months in the Hospital of Traditional Chinese Medicine of Zhengzhou City of Henan Province from March 2014 to March 2016. They were equally divided into a treatment group and a control group. Haemoglobin (HB) and hematocrit (HCT) of the treatment group increased significantly after treatment (p < 0.01), but less in the control group (p < 0.05); Also serum ferritin (SF) and transferrin saturation (TAST) of the treatment group increased significantly after treatment (p < 0.01); SF of the control group also increased significantly (p < 0.01) and TAST of the control group increased (p < 0.05) but less than in the treatment group. No obvious changes of serum creatinine (SCR), blood urea nitrogen (BUN), C-reactive protein (CRP) and superoxide dismutase (SOD) were found in either groups after treatment (p>0.05). Albumin (ALB) dosage of the treatment group increased after treatment (p < 0.05) while hemopoietin (EPO) decreased significantly (p < 0.01). ALB and EPO of the control group had no obvious changes after treatment (p>0.05). ALB level of the treatment group increased more significantly than in the control group (p < 0.05), while EPO dosage decreased more significantly than in the control group (p <0.05). Therefore, the combination of conventional western medicine and sodium ferrous chlorophyll can effectively improve anemia conditions of MHD patients and their quality of life.

A combined modality of carboplatin and photodynamic therapy suppresses epithelial-mesenchymal transition and matrix metalloproteinase-2 (MMP-2)/MMP-9 expression in HEp-2 human laryngeal cancer cells via ROS-mediated inhibition of MEK/ERK signalling pathway.

Photodynamic therapy (PDT) has been developed as a promising treatment modality for laryngeal cancer. 9-Hydroxypheophorbide α (9-HPbD), a novel chlorophyll-derived photosensitizer, has a longer absorption wavelength, which increases the penetration of light to malignant tissues. Carboplatin (CBDCA), a second-generation platinum derivative, also has gained more popularity for the treatment of laryngeal cancer. Our previous studies have elucidated that 9-HPbD-PDT could inhibit the migration and invasion of HEp-2 cells. The objective of this study is to investigate the change of migration and invasion of HEp-2 cells induced by a combined modality of CBDCA and 9-HPbD-PDT in vitro. A wound healing assay, cell migration assay and Matrigel invasion assay were used to evaluate the cellular migration and invasion. Reactive oxygen species (ROS) and Western blots for epithelial-mesenchymal transition (EMT) markers (E-cadherin, N-cadherin and vimentin), MMPs (MMP-2 and MMP-9) and MEK/ERK signalling pathway were performed to investigate the possible mechanisms that may be involved. We observed that CBDCA and 9-HPbD-PDT administration synergistically inhibited the migration and invasion of HEp-2 cells. Moreover, the combined modality cooperatively repressed the EMT process and down-regulated expressions of MMP-2 and MMP-9 via ROS-mediated inhibition of phosphorylation in the MEK/ERK signalling pathway. Our results suggested that the combination of CBDCA and 9-HPbD-PDT might be a promising therapeutic strategy for laryngeal cancer metastasis.

Efficacy of chlorophyll c2 for seasonal allergic rhinitis: single-center double-blind randomized control trial.

Chlorophyll c2 extracted from Sargassum horneri improved allergic symptoms in an animal model of allergic rhinitis. In the present study, we explored the efficacy of chlorophyll c2 in patients with seasonal allergic rhinitis. This was a single-center, randomized, double-blind placebo-controlled trial. Sixty-six patients aged 20-43 years, each with a 2-year history of seasonal allergic rhinitis, were randomly assigned to receive either a single daily dose (0.7 mg) of chlorophyll c2 or placebo for 12 weeks. The use of medications including H1-antihistamines and topical nasal steroids was recorded by rescue medication scores (RMSs) noted after 4, 8, and 12 weeks of treatment. Disease-specific quality of life was measured using the Japan Rhinitis Quality of Life Questionnaire (JRQLQ) both before and after 4, 8, and 12 weeks of treatment. The RMS at 8 weeks was significantly better in the chlorophyll c2 than the placebo group (mean RMS difference = -3.09; 95 % confidence interval = -5.96 to -0.22); the mean RMS at 4 weeks was only slightly better in the chlorophyll c2 group. The JRQLQ scores did not differ significantly between the two groups. Chlorophyll c2 would have a potential to be an alternative treatment for allergic rhinitis.

Apoptotic effect of pheophorbide a-mediated photodynamic therapy on DMBA/TPA-induced mouse papillomas.

Pheophorbide a (Pa) is a chlorine-based photosensitizer, and Pa-mediated photodynamic therapy (PDT) reportedly exhibits antitumor activity against various malignancies. The aim of our study was to investigate the therapeutic effect of Pa-mediated PDT on 7,12-dimethylbenz[a]anthracene (DMBA)/12-O-tetradecanoylphorobol-13-acetate (TPA)-induced mouse papillomas. Thirty mice received a topical application of DMBA/TPA on their backs to induce mouse papillomas. One week after two sessions of Pa-mediated PDT, immunohistochemical stains and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were performed to evaluate the apoptotic effects thereof on the papillomas. Among 63 mouse papillomas treated with Pa-mediated PDT, 17.5% of the lesions were completely removed 1 week after the first treatment, while 31.7% disappeared 1 week after the second treatment. Statistical analyses revealed significant differences in therapeutic outcomes for the Pa-mediated PDT group in comparison to a solvent-PDT group and a Pa group. Additionally, a marked downregulation of proliferating cell nuclear antigen expression, as well as upregulation of cleaved caspase 3 and cleaved poly(ADP-ribose) polymerase expression, was noted in the Pa-PDT group, compared to the solvent-PDT group and Pa group. TUNEL assay revealed higher apoptotic cell counts in the Pa-PDT group, although the difference was not statistically significant. Our data demonstrated that Pa-mediated PDT is effective in treating DMBA/TPA-induced mouse papillomas.

RUNX3 expression is associated with sensitivity to pheophorbide a-based photodynamic therapy in keloids.

Runt-related transcription factor 3 (RUNX3) has recently been reported to be a possible predictor of sensitivity of cancer cells for photodynamic therapy (PDT), a promising therapeutic modality for keloids. In this study, we aimed to elucidate the implications of RUNX3 for keloid pathogenesis and sensitivity to pheophorbide a-based PDT (Pa-PDT). RUNX3 and proliferating cell nuclear antigen (PCNA) expression were examined in 6 normal skin samples and 32 keloid tissue samples by immunohistochemistry. We found that RUNX3 expression was detected more often in keloid tissues than in dermis of normal skin. In keloid tissues, RUNX3 expression was significantly increased in patients presenting with symptoms of pain or pruritus, and was also significantly related to PCNA expression. The therapeutic effect of Pa-PDT was comparatively investigated in keloid fibroblasts (KFs) with and without RUNX3 expression. Significant differences were found after Pa-PDT between KFs with and without RUNX3 expression in cell viability, proliferative ability, type I collagen expression, generation of reactive oxygen species (ROS), and apoptotic cell death. In addition, RUNX3 expression was significantly decreased after Pa-PDT in KFs, and KFs with downregulation of RUNX3 showed significantly increased cell viability after Pa-PDT. Pa-PDT may be a potential therapeutic modality for keloids, and RUNX3, as a possible contributor to keloid pathogenesis, may improve sensitivity to Pa-PDT in KFs.

Targeted Photodynamic Therapy using a Vectorized Photosensitizer coupled to Folic Acid Analog induces Ovarian Tumor Cell Death and inhibits IL-6-mediated Inflammation.

Ovarian cancer (OC) is one of the most lethal cancers among women. Frequent recurrence in the peritoneum due to the presence of microscopic tumor residues justifies the development of new therapies. Indeed, our main objective is to develop a targeted photodynamic therapy (PDT) treatment of peritoneal carcinomatosis from OC to improve the life expectancy of cancer patients. Herein, we propose a targeted-PDT using a vectorized photosensitizer (PS) coupled with a newly folic acid analog (FAA), named PSFAA, in order to target folate receptor alpha (FRα) overexpressed on peritoneal metastasis. This PSFAA was the result of the coupling of pyropheophorbide-a (Pyro-a), as the PS, to a newly synthesized FAA via a polyethylene glycol (PEG) spacer. The selectivity and the PDT efficacy of PSFAA was evaluated on two human OC cell lines overexpressing FRα compared to fibrosarcoma cells underexpressing FRα. Final PSFAA, including the synthesis of a newly FAA and its conjugation to Pyro-a, was obtained after 10 synthesis steps, with an overall yield of 19%. Photophysical properties of PSFAA in EtOH were performed and showed similarity with those of free Pyro-a, such as the fluorescence and singlet oxygen quantum yields (Φf = 0.39 and ΦΔ = 0.53 for free Pyro-a, and Φf = 0.26 and ΦΔ = 0.41 for PSFAA). Any toxicity of PSFAA was noticed. After light illumination, a dose-dependent effect on PS concentration and light dose was shown. Furthermore, a PDT efficacy of PSFAA on OC cell secretome was detected inducing a decrease of a pro-inflammatory cytokine secretion (IL-6). This new PSFAA has shown promising biological properties highlighting the selectivity of the therapy opening new perspectives in the treatment of a cancer in a therapeutic impasse.

Synthesized Pheophorbide a-mediated photodynamic therapy induced apoptosis and autophagy in human oral squamous carcinoma cells.

BACKGROUND: Pheophorbide a (Pa) is a chlorine-based photosensitizer derived from an ethnopharmacological herb, and our group recently synthesized Pa by the removal of a magnesium ion and a phytyl group from chlorophyll-a. In this study, the effect of photodynamic therapy (PDT) with synthesized Pa was examined in a human oral squamous cell carcinoma (OSCC) cells. METHODS: Cells were treated with PDT with Pa, and reactive oxygen species (ROS) and mitochondrial membrane potential [ΔΨ (m)] were examined. Apoptosis was measured using annexin V staining and immunoblot. Autophagy was characterized by the increase in LC3B-II and the formation of autophagosome and acidic vesicular organelles (AVOs). RESULTS: Pa-PDT inhibited the proliferation of OSCC cells in a dose-dependent manner. Pa-PDT increased the number of apoptotic cells by inactivating ERK pathway. Pa-PDT also induced autophagy in OSCC cells evidenced by the increased levels of LC3 type II expression and the accumulation of AVOs. The inhibition of autophagy enhanced Pa-PDT-mediated cytotoxicity through an increase in necrosis. CONCLUSIONS: These results suggest that synthesized Pa-PDT exerts anti-tumor effects by inducing apoptosis and autophagy and provide novel evidence that Pa-PDT induces autophagy, and autophagy inhibition enhances Pa-PDT-mediated necrosis in OSCC cells.

Anti-inflammatory, gastroprotective and anti-ulcerogenic effects of red algae Gracilaria changii (Gracilariales, Rhodophyta) extract.

BACKGROUND: Gracilaria changii (Xia et Abbott) Abbott, Zhang et Xia, a red algae commonly found in the coastal areas of Malaysia is traditionally used for foods and for the treatment of various ailments including inflammation and gastric ailments. The aim of the study was to investigate anti-inflammatory, gastroprotective and anti-ulcerogenic activities of a mass spectrometry standardized methanolic extract of Gracilaria changii. METHODS: Methanolic extract of Gracilaria changii (MeOHGCM6 extract) was prepared and standardized using mass spectrometry (MS). Anti-inflammatory activities of MeOHGCM6 extract were examined by treating U937 cells during its differentiation with 10 µg/ml MeOHGCM6 extract. Tumour necrosis factors-α (TNF-α) response level and TNF-α and interleukin-6 (IL-6) gene expression were monitored and compared to that treated by 10 nM betamethasone, an anti-inflammatory drug. Gastroprotective and anti-ulcerogenic activities of MeOHGCM6 extract were examined by feeding rats with MeOHGCM6 extract ranging from 2.5 to 500 mg/kg body weight (b.w.) following induction of gastric lesions. Production of mucus and gastric juice, pH of the gastric juice and non-protein sulfhydryls (NP-SH) levels were determined and compared to that fed by 20 mg/kg b.w. omeprazole (OMP), a known anti-ulcer drug. RESULTS: MS/MS analysis of the MeOHGCM6 extracts revealed the presence of methyl 10-hydroxyphaeophorbide a and 10-hydroxypheophytin a, known chlorophyll proteins and several unidentified molecules. Treatment with 10 µg/ml MeOHGCM6 extract during differentiation of U937 cells significantly inhibited TNF-α response level and TNF-α and IL-6 gene expression. The inhibitory effect was comparable to that of betamethasone. No cytotoxic effects were recorded for cells treated with the 10 µg/ml MeOHGCM6 extract. Rats fed with MeOHGCM6 extract at 500 mg/kg b.w. showed reduced absolute ethanol-induced gastric lesion sizes by > 99% (p < 0.05). This protective effect was comparable to that conferred by OMP. The pH of the gastric mucus decreased in dose-dependent manner from 5.51 to 3.82 and there was a significant increase in NP-SH concentrations. CONCLUSIONS: Results from the study, suggest that the mass spectrometry standardized methanolic extract of Gracillaria changii possesses anti-inflammatory, gastroprotective and anti-ulcerogenic properties. Further examination of the active constituent of the extract and its mechanism of action is warranted in the future.

Photodynamic therapy of Pheophorbide a inhibits the proliferation of human breast tumour via both caspase-dependent and -independent apoptotic pathways in in vitro and in vivo models.

Breast cancer is conventionally treated by surgery and radiotherapy, with adjuvant chemotherapy and hormonotherapy as supplementary treatments. However, such treatments are associated with adverse side effects and drug resistance. In this study, Pheophorbide a (Pa), a photosensitizer isolated from Scutelleria barbata, was analysed for its antiproliferative effect on human breast tumour cells. The IC (inhibitory concentration)(50) of the combined treatment of Pa and photodynamic therapy (Pa-PDT) on human breast tumour MCF-7 cells was 0.5 µm. Mechanistic studies in MCF-7 cells demonstrated that Pa was localized in the mitochondria, and reactive oxygen species were found to be released after Pa-PDT. Apoptosis was the major mechanism responsible for the tumour cell death, and mitochondrial membrane depolarization and cytochrome c release highlighted the role of mitochondria in the apoptotic mechanism. Up-regulation of tumour suppressor protein p53, cleavage of caspase-9 and poly (ADP-ribose) polymerase suggested that the caspase-dependent pathway was induced, while the release of apoptosis-inducing factors demonstrated that the apoptosis was also mediated by the caspase-independent mechanism. In vivo study using the mouse xenograft model showed a significant inhibition of MCF-7 tumour growth by Pa-PDT. Together, the results of this study provide a basis for understanding and developing Pa-PDT as a cure for breast cancer.

The activity of G-ROS and the predominant role of Type II reaction in the photodynamic therapy using 9-hydroxypheophorbide-α for HeLa cell lines.

Photodynamic therapy (PDT) is a treatment modality that destroys the tumor. It activates the photosensitizer with the light of a specific wavelength, where the light is well absorbed by the photosensitizer, thus causing a fatal injury and thereby leading to a tumor necrosis. To date, a hematoporphyrin-derived photosensitizer has been widely used. It is disadvantageous, however, in that it causes a long-term photo-toxicity and has a poor selectivity for the tumor. This had led to the development of a chlorophyll-derived photosensitizer. We conducted this study to elucidate the mechanisms by which the activity of ROS is involved in the PDT using a novel type of chlorophyll-derived photosensitizer, 9-hydroxypheophorbide-α (9-HpbD-α), for the HeLa cell lines. Besides, we also attempted to determine which reaction plays a predominant role in the synthesis of ROS, either Type I reaction or Type II one, when both reactions are involved in the synthesis of ROS during the PDT using 9-HpbD-α. Our results showed not only that the activity of ROS is involved in the PDT using 9-HpbD-α in human uterine cervical cancer cell lines but also that the mechanisms of PDT are based on Type II reaction where the singlet oxygen is involved.

The role of porphyrin chemistry in tumor imaging and photodynamic therapy.

In recent years several review articles and books have been published on the use of porphyrin-based compounds in photodynamic therapy (PDT). This critical review is focused on (i) the basic concept of PDT, (ii) advantages of long-wavelength absorbing photosensitizers (PS), (iii) a brief discussion on recent advances in developing PDT agents, and (iv) the various synthetic strategies designed at the Roswell Park Cancer Institute, Buffalo, for developing highly effective long-wavelength PDT agents and their utility in constructing the conjugates with tumor-imaging and therapeutic potential (Theranostics). The clinical status of certain selected PDT agents is also summarized (205 references).