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Showing papers on "Protoporphyrin IX published in 2013"


Journal ArticleDOI
TL;DR: A carbon quantum dot (CQD)-protoporphyrin (IX) sensitisier conjugate was designed to exploit the large two-photon absorption cross section of CQDs and enable the indirect excitation of the sensitiser with 800 nm irradiation via FRET.

101 citations


Journal ArticleDOI
TL;DR: ABCB6 overexpression is a potential approach to enhance accumulation of PpIX for optimizing the subjective discrimination of vague fluorescence and improving the efficacy of ALA-based photodynamic therapy.
Abstract: Glioma recurrence usually occurs close to the tumor resection margins as a result of residual infiltrating glioma cells. 5-aminolevulinic acid (ALA) fluorescence-guided resection of gliomas has been demonstrated to enhance discrimination of tumor tissue and to improve survival. ALA-based photodynamic therapy is an effective albeit still experimental adjuvant treatment option for gliomas. However, insufficient protoporphyrin IX (PpIX) accumulation may limit the benefits of fluorescence-guided resection and photodynamic therapy. We investigated the expression of the ATP-binding cassette transporter ABCB6, which regulates porphyrin synthesis, in surgical specimens from human gliomas and manipulated ABCB6 in human glioma cell lines. Our findings demonstrated that expression levels of ABCB6 were greatly elevated in human gliomas compared with normal brain tissues and correlated with World Health Organization histologic grade. A previously undescribed finding was that ABCB6 mRNA expression in solidly fluorescing tumor tissues was higher than that in vaguely fluorescing tumors, suggesting that ABCB6 may be at least in part responsible for PpIX accumulation in glioma cells. Accordingly, ABCB6 overexpression in glioma cell lines caused a marked increase in intracellular levels of PpIX, and was more sensitive to ALA-induced photodynamic therapy—events that could be prevented by silencing ABCB6 via siRNA treatment. Our findings indicate a crucial role of ABCB6 in ALA metabolism and accumulation of PpIX in glioma. ABCB6 overexpression is a potential approach to enhance accumulation of PpIX for optimizing the subjective discrimination of vague fluorescence and improving the efficacy of ALA-based photodynamic therapy.

78 citations


Journal ArticleDOI
TL;DR: The induction of PEPT1 gene and the suppression of ABCG2 gene expression are among the key molecular mechanisms underlying tumor-specific PpIX accumulation after the administration of ALA in bladder cancer.

73 citations


Journal ArticleDOI
TL;DR: This probe provided an effective platform for reliable detection of Cu(2+) with a detection limit as low as 3.0nM, the high sensitivity was attributed to the strong metalation of PPIX with Cu( 2+) catalyzed by G-quadruplex (PS5.M).

69 citations


Journal ArticleDOI
TL;DR: PpIX-mediated SDT had apoptotic effects on THP-1 macrophages via generation of intracellular singlet oxygen and disruption of the cytoskeleton and may be a potential treatment to attenuate progression of atherosclerotic plaque.
Abstract: Background Sonodynamic therapy (SDT) was developed as a localized ultrasound-activated cytotoxic therapy for cancer. The ability of SDT to destroy target tissues selectively is especially appealing for atherosclerotic plaque, in which selective accumulation of the sonosensitizer, protoporphyrin IX (PpIX), had been demonstrated. Here we investigate the effects of PpIX-mediated SDT on macrophages, which are the main culprit in progression of atherosclerosis.

64 citations


Journal ArticleDOI
TL;DR: To monitor the amount of PpIX in tissues, techniques have been developed to measure Ppix-specific fluorescence, which provides information useful for monitoring the abundance and location of the photosensitizer before and during the illumination phase of PDT.
Abstract: Photodynamic therapy (PDT) is a treatment modality that uses a specific photosensitizing agent, molecular oxygen, and light of a particular wavelength to kill cells targeted by the therapy. Topically administered aminolevulinic acid (ALA) is widely used to effectively treat cancerous and precancerous skin lesions, resulting in targeted tissue damage and little to no scarring. The targeting aspect of the treatment arises from the fact that ALA is preferentially converted into protoporphyrin IX (PpIX) in neoplastic cells. To monitor the amount of PpIX in tissues, techniques have been developed to measure PpIX-specific fluorescence, which provides information useful for monitoring the abundance and location of the photosensitizer before and during the illumination phase of PDT. This review summarizes the current state of these fluorescence detection techniques. Non-invasive devices are available for point measurements, or for wide-field optical imaging, to enable monitoring of PpIX in superficial tissues. To gain access to information at greater tissue depths, multi-modal techniques are being developed which combine fluorescent measurements with ultrasound or optical coherence tomography, or with microscopic techniques such as confocal or multiphoton approaches. The tools available at present, and newer devices under development, offer the promise of better enabling clinicians to inform and guide PDT treatment planning, thereby optimizing therapeutic outcomes for patients.

62 citations


Journal ArticleDOI
TL;DR: Protoporphyrin IX (PpIX) conjugated gold nanoparticle (GNP) was synthesized, characterized, and used for the delivery of a hydrophobic photosensitizer to a cervical cancer cell line and its properties indicate that PpIX-GNP conjugates could be used as a photosenitizer in photodynamic therapy (PDT) through the formulation of singlet oxygen.

56 citations


Journal ArticleDOI
TL;DR: Gefitinib can inhibit ABCG2-mediated PpIX efflux from malignant brain tumor cells to increase the intracellular Ppix and thereby enhance the PDT effect.

51 citations


Journal ArticleDOI
TL;DR: Results show that PEG-Chito-5-ALA nanoparticles are promising candidates for photodynamic therapy of colon cancer cells.
Abstract: H NMR spectra showed that 5-ALA was incorporated in the core of the nanoparticles. In the absence of light irradiation, all components such as 5-ALA, empty nanoparticles, and PEG-Chito-5-ALA nanoparticles did not affect the viability of cells. However, 5-ALA or PEG-Chito-5-ALA nanoparticles induced tumor cell death under light irradiation, and the viability of tumor cells was dose-dependently decreased according to the increase in irradiation time. In particular, PEG-Chito-5-ALA nanoparticles induced increased phototoxicity and higher protoporphyrin IX accumulation into the tumor cells than did 5-ALA alone. Furthermore, PEG-Chito-5-ALA nanoparticles accelerated apoptosis/necrosis of tumor cells, compared to 5-ALA alone. Conclusion: PEG-Chito-5-ALA nanoparticles showed superior delivery capacity of 5-ALA and phototoxicity against tumor cells. These results show that PEG-Chito-5-ALA nanoparticles are promising candidates for photodynamic therapy of colon cancer cells.

48 citations


Journal ArticleDOI
TL;DR: Protoporphyrin IX (PpIX) distribution induced by topical and intra-tumoral administration of the prodrug ALA in basal and squamous cell carcinoma murine models is quantified by using spatial frequency domain imaging (SFDI) and validated by analysis of the ex vivo extraction of PpIX.
Abstract: 5-aminolaevulinic acid photodynamic therapy (ALA-PDT) is an attractive treatment option for nonmelanoma skin tumors, especially for multiple lesions and large areas. The efficacy of ALA-PDT is highly dependent on the photosensitizer (PS) concentration present in the tumor. Thus it is desirable to quantify PS concentration and distribution, preferably noninvasively to determine potential outcome. Here we quantified protoporphyrin IX (PpIX) distribution induced by topical and intra-tumoral (it) administration of the prodrug ALA in basal and squamous cell carcinoma murine models by using spatial frequency domain imaging (SFDI). The in vivo measurements were validated by analysis of the ex vivo extraction of PpIX. The study demonstrates the feasibility of non-invasive quantification of PpIX distributions in skin tumors.

45 citations


Journal ArticleDOI
TL;DR: ALA-PDT induced PC-3 cell death by the mechanisms of both necrosis and apoptosis through a caspase-independent mitochondrial pathway, suggesting that ALA- PDT could be a new modality for focal therapy of prostate cancer.

Journal ArticleDOI
TL;DR: It is anticipated that a new nanoconjugate composed of Protoporphyrin IX and gold nanoparticles can act as an efficient sonoluminescence agent and could be introduced as a novel sonosensitizer for sonodynamic therapy.

Journal ArticleDOI
TL;DR: Results demonstrated ALA‐PDT dominantly induced apoptosis over necrosis by direct action on UC as well as via antiangiogenic action on neovacular endothelial cells, suggesting that the therapeutic damage by ALA-PDT could be kept to a minimum in the surrounding normal tissues.
Abstract: The purpose of the present study was to investigate the mechanism of photodynamic therapy (PDT) supplemented with exogenously added 5-aminolevulinic acid (ALA) on human urothelial cancer (UC). Moreover, we aimed to determine whether the therapeutic effects of ALA-based PDT (ALA-PDT) for UC could be enhanced by deferoxamine (DFX), an inhibitor of ferrochelatase. The efficiency of ALA-PDT on these cells was analyzed using flow cytometry and the type of cell death was also assessed. The ALA-PDT promoting effect of DFX was examined on both UC cells and human umbilical vein endothelial cells (HUVEC). The ALA-PDT decreased levels of mitochondrial membrane potential and induced cell death mainly via apoptosis in these cells. Moreover, inhibition of ferrochelatase by DFX led to an increase of protoporphyrin IX (PpIX) accumulation and enhanced the effect of ALA-PDT on UC cells. We further investigated the effect of DFX on in vivo PDT with a tumor-bearing animal model and found that DFX efficiently enhanced tumor cell apoptosis. ALA-PDT induced death of neovascular endothelial cells in tumors but did not affect small vessel endothelial cells in normal tissues surrounding the tumor. Furthermore, DFX enhanced inhibition of neovascularization. These results demonstrated ALA-PDT dominantly induced apoptosis over necrosis by direct action on UC as well as via antiangiogenic action on neovacular endothelial cells, suggesting that the therapeutic damage by ALA-PDT could be kept to a minimum in the surrounding normal tissues. In addition, increased accumulation of PpIX by DFX could enhance this effectiveness of ALA-PDT.

Journal ArticleDOI
TL;DR: Patients who showed a fluorescence level before PDT treatment above a certain threshold had a complete recovery at 33.6 (±3.0) months and were able to predict its long-term outcome.
Abstract: Background: Photodynamic therapy (PDT) with Metvix® is a good therapeutic option to treat actinic keratosis, but it presents drawbacks (pain, lesion recurrences,

Journal ArticleDOI
TL;DR: The results from this study show a possible cause of reduced sensitivity to ALA/MAL-PDT, with a potential solution to overcome this effect in certain tissue types.
Abstract: Background ABCG2 is an ATP-binding cassette transporter protein which has a role in the regulation of endogenous protoporphyrin IX (PpIX) levels. Objective To understand the influence of ABCG2 on porphyrin-based photodynamic therapy (PDT) and fluorescence diagnosis (FD), we examined the role of endogenous ABCG2 in four human cell lines from the epidermis (HaCaT keratinocytes), oesophagus (OE19 adenocarcinoma), brain (SH-SY5Y neuroblastoma) and bladder (HT1197 carcinoma). Methods Cells were incubated with ALA or MAL in the presence or absence of the ABCG2 activity inhibitor Ko-143. Porphyrin accumulation was detected by spectrofluorimetric analysis and high performance liquid chromatography (HPLC) with porphyrin localisation observed by confocal laser scanning microscopy. PDT efficacy was assessed 24 h post irradiation (1.5 J/cm2 red light) by the neutral red (NR) assay. Results We show cell-specific differences when Ko-143 was co-incubated with ALA or, in particular with, MAL. Enhanced PDT-induced cell kill was shown in HaCaT, OE19 and HT1197 cells, but not SH-SY5Y cells and could be explained by porphyrin accumulation and expression of ABCG2. We have also found that despite high levels of intracellular PpIX, the OE19 cells were protected from phototoxic cell death by PpIX compartmentalisation. This could be reversed by Ko-143. Conclusion The results from this study show a possible cause of reduced sensitivity to ALA/MAL-PDT, with a potential solution to overcome this effect in certain tissue types. The potential to improve PDT with Ko-143 remains promising.

Journal ArticleDOI
TL;DR: Analysis of the effect of ALA administration with X-ray irradiation of mouse B16-BL6 melanoma cells in vitro and in vivo suggests ALA may improve the efficacy of cancer radiotherapy by acting as a radiomediator.
Abstract: 5-Aminolevulinic acid (ALA) is a photosensitizer used in photodynamic therapy (PDT) because it causes preferential accumulation of protoporphyrin IX (PpIX) in tumor cells, where it forms singlet oxygen upon light irradiation and kills the tumor cells. Our previous study demonstrated that PpIX enhances generation of reactive oxygen species by physicochemical interaction with X-rays. We investigated the effect of ALA administration with X-ray irradiation of mouse B16-BL6 melanoma cells in vitro and in vivo. ALA facilitates PpIX accumulation in tumor cells and enhances ROS generation in vitro. Tumor suppression significantly improved in animals treated with fractionated doses of radiation (3 Gy × 10; total, 30 Gy) with local administration of 50 mg/kg ALA at 24 h prior to fractional irradiation. These results suggest ALA may improve the efficacy of cancer radiotherapy by acting as a radiomediator.

Journal ArticleDOI
TL;DR: Results showed that ALA-AuNPs combinations induced cell death via ROS-mediated apoptosis after PDT and when exposed to light at their resonance wavelength, AuNP2 combined with ALA result in cytotoxicity and cell injury in greater extension than ALA and ALA -AuNP1 combination.

Journal ArticleDOI
TL;DR: The successful synthesis of 64Cu-chelated porphyrin photosensitizers and their tumor-targeting peptide conjugates under conditions in which radiolysis is suppressed is reported on.
Abstract: Targeted photodynamic therapy (PDT) is necessary for preventing the side effects associated with PDT, such as photosensitivity caused by the distribution of photosensitizers into normal tissues. In the development of targeted PDT agents, a simple evaluation system of in vivo pharmacokinetics, as well as target cell uptake, is absolutely imperative. We hypothesized that 64Cu chelation with porphyrin photosensitizer-biomacromolecule conjugates may become a simple and versatile labeling strategy for this purpose. Protoporphyrin IX (PPIX) and a bombesin (BBN) analog, that interacts with the gastrin-released peptide (GRP) receptor, were used as a photosensitizer and tumor-targeting peptide, respectively. Then, a conjugate of PPIX and BBN analog linked via short polyethylene glycol (PPIX-PEG6-BBN analog) was synthesized and used as a targeted PDT agent. In addition, a 64Cu-chelated PPIX-PEG6-BBN analog was synthesized under optimized reaction conditions. Lastly, cell uptake study and PET image-based pharmacokinetic analyses of the PPIX-PEG6-BBN analog were carried out in a human prostate cancer cell line, PC-3, which highly expresses the GRP receptor, and PC-3 tumor-bearing mice. It was confirmed that degradation (thought to be based on radiolysis) occurs, and large amounts of 64Cu-labeling compounds are wasted in the reaction mixture. Interestingly, the addition of ethanol into the reaction mixture provides an effective solution for this problem. As for cell uptake study, the [64Cu]PPIX-PEG6-BBN analog demonstrated significantly higher uptake for PC-3 cells than [64Cu]PPIX and, in addition, the uptake of [64Cu]PPIX-PEG6-BBN analog was significantly inhibited by adding excess cold BBN analog peptide. PET image-based pharmacokinetic evaluation revealed that [64Cu]PPIX-PEG6-BBN analog and [64Cu]PPIX rapidly accumulate into the liver and kidney, circulate in blood for a long time compared with normal peptides, and distribute at a low level in the tumor. This result suggested that in vivo biodistribution of PPIX-PEG6-BBN analog is mainly dependent on the lipophilicity of PPIX. Ex vivo measurements of radioactivity distribution after PET studies showed that although there was no remarkable difference in the tumor/skin ratio of radioactivity between [64Cu]PPIX-PEG6-BBN analog and [64Cu]PPIX, the pancreas (an organ that also expresses GRP receptors)/skin ratio was significantly higher in the case of [64Cu]PPIX-PEG6-BBN analog. We report on the successful synthesis of 64Cu-chelated porphyrin photosensitizers and their tumor-targeting peptide conjugates under conditions in which radiolysis is suppressed. This labeling strategy with porphyrin photosensitizers may be of value for the rapid development of ideal targeted PDT agents.

Journal ArticleDOI
TL;DR: It is demonstrated that ABCG2‐deficient hepatocytes have increased amounts of fragmental mitochondria accompanied by disruption of mitochondrial dynamics and functions, which led to upregulation of DRP‐1‐mediated mitochondrial fission.

Journal ArticleDOI
TL;DR: It was demonstrated that Ppix was quickly excreted by tumor cells out to the extracellular space, and that even normal brain tissue can produce PpIX in the presence of 5-ALA.
Abstract: Objective: (PpIX) fluorescence induced by 5-aminolevulinic acid (5-ALA), which appears in various tumors including malignant gliomas, is a good navigator for tumor resection. However, some non-neoplastic tissue also shows a weak PpIX fluorescence. The origin of non-neoplastic PpIX is still unknown, and three hypotheses on its origins can be proposed: tumor cell-derived PpIX followed by dispersal via bulk flow, direct PpIX production by normal brain or gliotic brain tissue, or PpIX produced in other organs leaking from the tumor vessels. We investigated the possibility of these three origins experimentally. Methods: In vitro, we exposed various cultured glioma and meningioma cell lines to different conditions of 5-ALA. After this, the degree of fluorescence of the culture medium and cells was each quantitatively measured and analyzed by means of photometrical assay. We administered 5-ALA directly into the normal brains of rats by using convection-enhanced delivery technique, and we also administer...

Journal ArticleDOI
TL;DR: The bare, five-coordinate iron(II) heme nitrosyl complex [Fe(2)hemeH(NO)]+ was obtained in this paper.
Abstract: The bare, five-coordinate iron(II) heme nitrosyl complex [Fe(II)hemeH(NO)]+, namely, an iron(II) complex of the dianion of protoporphyrin IX holding a proton on one vinyl group, has been obtained i...

Journal ArticleDOI
23 Jul 2013-PLOS ONE
TL;DR: The novel mechanistic insights obtained from this study present a new starting point for future rational design of more efficient PPO inhibitors based on the product-bound PPO structure.
Abstract: Protoporphyrinogen IX oxidase (PPO; EC 1.3.3.4) is an essential enzyme catalyzing the last common step in the pathway leading to heme and chlorophyll biosynthesis. Great interest in PPO inhibitors arises from both its significance to agriculture and medicine. However, the discovery of PPO inhibitors with ultrahigh potency and selectivity is hampered due to lack of structural and mechanistic understanding about the substrate recognition, which remains a longstanding question central in porphyrin biology. To understand the mechanism, a novel binding model of protogen (protoporphyrinogen IX, the substrate) was developed through extensive computational simulations. Subsequently, amino acid residues that are critical for protogen binding identified by computational simulations were substituted by mutagenesis. Kinetic analyses of these mutants indicated that these residues were critical for protogen binding. In addition, the calculated free energies of protogen binding with these mutants correlated well with the experimental data, indicating the reasonability of the binding model. On the basis of this novel model, the fundamental mechanism of substrate recognition was investigated by performing potential of mean force (PMF) calculations, which provided an atomic level description of conformational changes and pathway intermediates. The free energy profile revealed a feedback inhibition mechanism of proto (protoporphyrin IX, the product), which was also in agreement with experimental evidence. The novel mechanistic insights obtained from this study present a new starting point for future rational design of more efficient PPO inhibitors based on the product-bound PPO structure.

Journal ArticleDOI
TL;DR: The results indicate that NPs are suitable for PpIX encapsulation showing minimal permeation through the skin and a localized effect, characteristics of a potential and promising delivery system for PDT‐associated treatments of skin cancers, photodiagnosis and their off‐label uses.
Abstract: We report the development of d, l lactic co-glycolic acid) (PLGA)-based nanoparticles (NPs) for topical delivery of protoporphyrin IX (PpIX), a photosensitizer (PS), in treatments like photodynamic therapy (PDT) of skin cancers. PpIX-NPs were obtained in ~75.0% yield, encapsulation efficiency of 67.7%, drug content of 50.3 μg mg−1, average diameter of 290 nm maintained up to 30 days and a zeta potential of 32.3 mV. Sustained in vitro release of PpIX through artificial membranes following Higuchi kinetics was kept up to 10 days. In vitro retentions of PpIX both in stratum corneum (SC) and epidermis + dermis ([EP + D]) were higher from NPs (23.0 and 10.0 times, respectively) compared to control solutions at all times. Quantification of PpIX by extraction, after in vivo skin application of NPs-PpIX on hairless mice, showed higher retention of the PS both in SC and in [EP + D] (3.0 and 2.0 times, respectively) compared to control solutions. Taken together, the results indicate that NPs are suitable for PpIX encapsulation showing minimal permeation through the skin and a localized effect, characteristics of a potential and promising delivery system for PDT-associated treatments of skin cancers, photodiagnosis and their off-label uses.

Journal ArticleDOI
TL;DR: The decrease of the expression of frataxin unregulated by p53 in tumor cells enhances ALA‐induced photo‐damage, by down‐regulation of mitochondrial functions.
Abstract: Mitochondrial frataxin is involved in various functions such as iron homeostasis, iron-sulfur cluster biogenesis, the protection from oxidative stress and apoptosis and acts as a tumor suppressor protein. We now show that the expression of frataxin is stimulated in a p53-dependent manner and prove that frataxin is a direct p53 target gene by showing that the p53-responsive element in the promoter of the mouse frataxin gene is bound by p53. The bacterial expression of human frataxin stimulated maturation of human ferrochelatase, which catalyzes the insertion of iron into protoporphyrin at the last step of heme biosynthesis. Overexpression of frataxin in human cancer A431 and HeLa cells lowered 5-aminolevulinic acid(ALA)-induced accumulation of protoporphyrin and induced resistance to ALA-induced photo-damage, whereas p53 silencing with siRNA in non tumor HEK293T cells down-regulated the expression of frataxin and increased the accumulation of protoporphyrin. Thus, the decrease of the expression of frataxin unregulated by p53 in tumor cells enhances ALA-induced photo-damage, by down-regulation of mitochondrial functions.

Journal ArticleDOI
TL;DR: In this paper, a microreview survey of applications of protoporphyrin IX derivatives in the fields of supramolecular science, artificial photosynthesis and biomedical science is presented.

Journal ArticleDOI
TL;DR: The binding specificity of HmuY towards non-iron metalloporphyrins which may be employed as antimicrobials to treat periodontitis is analyzed, corroborating binding of non- iron metalliporphyrin acquisition by P. gingivalis and adding to understanding of the interactions with porphyr in derivatives.
Abstract: Porphyromonas gingivalis, a major etiological agent of chronic periodontitis, acquires haem from host haemoproteins through a haem transporter HmuR and a haemophore HmuY. The aim of this study was to analyse the binding specificity of HmuY towards non-iron metalloporphyrins which may be employed as antimicrobials to treat periodontitis. HmuY binds gallium(III), zinc(II), cobalt(III), manganese(III), nickel(II), and copper(II) protoporphyrin IX but in a manner different to iron(III) protoporphyrin IX which uses His134 and His166 as axial ligands. The metal ions in Ga(III)PPIX and Zn(II)PPIX can accept only His166 as an axial ligand, whereas nickel(II) and copper(II) interact exclusively with His134. Two forms of pentacoordinate manganese(III) are present in the Mn(III)PPIX–HmuY complex since the metal accepts either His134 or His166 as a single axial ligand. The cobalt ion is hexacoordinate in the Co(III)PPIX–HmuY complex and binds His134 and His166 as axial ligands; however, some differences in their environments exist. Despite different coordination modes of the central metal ion, gallium(III), zinc(II), cobalt(III), and manganese(III) protoporphyrin IX bound to the HmuY haemophore cannot be displaced by excess haem. All of the metalloporphyrins examined bind to a P. gingivalis wild-type strain with higher ability compared to a mutant strain lacking a functional hmuY gene, thus corroborating binding of non-iron metalloporphyrins to purified HmuY protein. Our results further clarify the basis of metalloporphyrin acquisition by P. gingivalis and add to understanding of the interactions with porphyrin derivatives which exhibit antimicrobial activity against P. gingivalis.

Journal ArticleDOI
TL;DR: It is suggested that accumulation of PpIX is determined by the activities of ABCG2 and FECH and that treatment with a combination of their inhibitors improves the efficacy of PDT for oral cancer, especially in the presence of serum.
Abstract: Ever since protoporphyrin IX (PpIX) was discovered to accumulate preferentially in cancer cells after 5-aminolevulinic acid (ALA) treatment, photodynamic treatment or therapy (PDT) has been developed as an exciting new treatment option for cancer patients. However, the level of PpIX accumulation in oral cancer is fairly low and insufficient for PDT. Ferrochelatase (FECH) and ATP-binding cassette transporter G2 (ABCG2) are known to regulate PpIX accumulation. In addition, serum enhances PpIX export by ABCG2. We investigated here whether and how inhibitors of FECH and ABCG2 and their combination could improve PpIX accumulation and PDT efficacy in an oral cancer cell line in serum-containing medium. ABCG2 inhibitor and the combination of ABCG2 and FECH inhibitors increased PpIX in the presence of fetal bovine serum (FBS) in an oral cancer cell line. Analysis of ABCG2 gene silencing also revealed the involvement of ABCG2 in the regulation of PpIX accumulation. Inhibitors of FECH and ABCG2, and their combination increased the efficiency of ALA-PDT even in the presence of FBS. ALA-PDT-induced cell death was accompanied by apoptotic events and lipid peroxidation. These results suggest that accumulation of PpIX is determined by the activities of ABCG2 and FECH and that treatment with a combination of their inhibitors improves the efficacy of PDT for oral cancer, especially in the presence of serum.

Journal ArticleDOI
TL;DR: It is suggested that low concentrations of haem-related molecules with porphyrin rings in the presence of other stimulating agent are important for ROS production and possibly the onset of TRALI.
Abstract: Background Transfusion-related acute lung injury (TRALI) is associated with vascular endothelial cell injury following neutrophil activation. Recently, it has been suggested that haem-related molecules induce activation of neutrophils and that erythrocyte-derived substances contained in blood preparations are involved in TRALI. We observed the morphological effects and reactive oxygen species (ROS) production of haem-related molecules and investigated the effects of signal transduction inhibitors on haem-induced neutrophil activation. Materials and methods The polymorphonuclear cell fraction was isolated and stimulated using a control stimulant, PMA or fMLP, or by haem-related molecules, haemin, ferric citrate, or protoporphyrin IX. After stimulation, neutrophil was analysed using electron microscopy, a flowcytometer (FCM) and confocal laser scanning microscope to determine the fluorescent intensity of aminophenyl fluorescein (to detect ROS). Results In FCM analysis, haemin and protoporphyrin IX, both of which have a porphyrin ring, induced ROS production in neutrophils. Ferric citrate, which has no porphyrin ring, did not induce neutrophil activation. Haemin alone induced ROS production at relatively high concentrations, whereas low-level fMLP acted as an agonist in the presence of low concentrations of haemin. Haem-related molecules induced ROS production in neutrophil granules through signal transduction in a way similar to PMA. However, in electron microscopy studies, haemin stimulated neutrophils showed minute process at their surface and did not show the vacuolation observable following stimulation with PMA or fMLP. Discussion We suggest that low concentrations of haem-related molecules with porphyrin rings in the presence of other stimulating agent are important for ROS production and possibly the onset of TRALI. The ROS production induced by these molecules is dependent on a signal transduction pathway in a way similar to PMA.

Journal ArticleDOI
TL;DR: The finding indicates a localized effect of PpIX-NPs in the epidermis plus dermis--a site of action for topical PDT--and suggests a potential use in PDT associated to skin cancer treatments.
Abstract: Poly(D,L lactic-co-glycolic acid) (PLGA) based nanoparticles (NPs) are proposed for topical delivery of Protoporphyrin IX (PpIX) in Photodynamic Therapy of skin cancers. PpIX loaded into PLGA NPs showed nanometric average diameter (-280 nm), spherical forms and pH - 5.7, conditions suitable for topical application. In vitro release of PpIX from NPs was sustained up to 24 hr with a burst release effect of about 37.0% at 2 hr. Penetration and distribution of PpIX in hairless mice skin was determined by fluorescence microscopy 8 or 24 hrs after application of PpIX-NPs in the animals. At 24 hours, areas located in deeper regions of the skin were found to have greater fluorescence intensity. The finding indicates a localized effect of PpIX-NPs in the epidermis plus dermis--a site of action for topical PDT--and suggests a potential use of PpIX-NPs in PDT associated to skin cancer treatments.

Journal ArticleDOI
TL;DR: The multi-modal action of PpIX + βCD can efficiently transport tamoxifen citrate intracellularly and confer cell death through a synergy of photo‐ and chemotoxicity and was demonstrated in MCF7 cells.
Abstract: Topical or systemic administration of 5-aminolevulinic acid (ALA) and its esters results in increased production and accumulation of protoporphyrin IX (PpIX) in cancerous lesions allowing effective application of photodynamic therapy (PDT). The large concentrations of exogenous ALA practically required to bypass the negative feedback control exerted by heme on enzymatic ALA synthesis and the strong dimerization propensity of ALA are shortcomings of the otherwise attractive PpIX biosynthesis. To circumvent these limitations and possibly enhance the phototoxicity of PpIX by adjuvant chemotherapy, covalent bonding of PpIX with a drug carrier, β-cyclodextrin (βCD) was implemented. The resulting PpIX + βCD product had both carboxylic termini of PpIX connected to the CD. PpIX + βCD was water soluble, was found to preferentially localize in mitochondria rather than in lysosomes both in MCF7 and DU145 cell lines while its phototoxiciy was comparable to that of PpIX. Moreover, PpIX + βCD effectively solubilized the breast cancer drug tamoxifen metabolite N-desmethyltamoxifen (NDMTAM) in water. The PpIX + βCD/NDMTAM complex was readily internalized by both cell lines employed. Furthermore, the multimodal action of PpIX + βCD was demonstrated in MCF7 cells: while it retains the phototoxic profile of PpIX and its fluorescence for imaging purposes, PpIX + βCD can efficiently transport tamoxifen citrate intracellularly and confer cell death through a synergy of photo- and chemotoxicity.