Showing papers on "Protoporphyrin IX published in 2010"
TL;DR: The results show that fCNA can be taken up more easily by HT29 and Caco-2 cell lines after short-term uptake period, most likely via receptor-mediated endocytosis, and the PpIX accumulates in cancer cells as a function of the folate receptor expression and the folic acid modification.
252 citations
TL;DR: This system showed pH-responsive micellization/demicellization transition at tumoral acidic pH and enabled in vivo tumor diagnosis and therapy simultaneously.
176 citations
TL;DR: The results show that saflufenacil is a new PPO-inhibiting, peroxidizing herbicide in multiple crops, including corn.
Abstract: Saflufenacil (Kixor™) is a new herbicide of the pyrimidinedione chemical class for preplant burndown and selective preemergence dicot weed control in multiple crops, including corn. In this study, the mode of action of saflufenacil was investigated. For initial characterization, a series of biotests was used in a physionomics approach for comprehensive physiological profiling of saflufenacil effects. With the use of treated duckweed plants, metabolite profiling was performed based on quantification of metabolite changes, relative to untreated controls. Physiological and metabolite profiling suggested a mode of action similar to inhibitors of protoporphyrinogen IX oxidase (PPO) in tetrapyrrole biosynthetic pathway. Saflufenacil inhibited PPO enzyme activity in vitro with 50% inhibition of 0.4 nM for the enzymes isolated from black nightshade, velvetleaf, and corn. PPO inhibition by saflufenacil caused accumulations of protoporphyrin IX (Proto) and hydrogen peroxide (H2O2) in leaf tissue of black n...
150 citations
TL;DR: The most recent and promising developments in PDT include the discovery of new photosensitizers, the exploitation of new drug delivery systems and the combination of other modalities, which will all contribute to increasing PDT therapeutic efficacy and improving outcome.
Abstract: Photodynamic therapy (PDT) is a noninvasive procedure that involves a photosensitizing drug and its subsequent activation by light to produce reactive oxygen species that specifically destroy target cells. Recently, PDT has been widely used in treating non-melanoma skin malignancies, the most common cancer in the USA, with superior cosmetic outcomes compared with conventional therapies. The topical 'photosensitizers' commonly used are 5-aminolevulinic acid (ALA) and its esterified derivative methyl 5-aminolevulinate, which are precursors of the endogenous photosensitizer protoporphyrin IX. After treatment with ALA or methyl 5-aminolevulinate, protoporphyrin IX preferentially accumulates in the lesion area of various skin diseases, which allows not only PDT treatment but also fluorescence diagnosis with ALA-induced porphyrins. Susceptible lesions include various forms of non-melanoma skin cancer such as actinic keratosis, basal cell carcinoma and squamous cell carcinoma. The most recent and promising developments in PDT include the discovery of new photosensitizers, the exploitation of new drug delivery systems and the combination of other modalities, which will all contribute to increasing PDT therapeutic efficacy and improving outcome. This article summarizes the main principles of PDT and its current clinical use in the management of non-melanoma skin cancers, as well as recent developments and possible future research directions.
136 citations
TL;DR: The average PpIX concentration in vital grade IV tumor parts was in the range previously shown sufficient for PDT‐induced tissue damage following irradiation, however, the feasibility of PDT for grade III brain tumors and for grade IV brain tumors displaying mainly necrotic tissue areas without solid tumor parts needs to be further investigated.
Abstract: Protoporphyrin IX (PpIX) produced from exogenous, orally administered 5-aminolevulinic acid (ALA) displays high tumor-selective uptake and is being successfully employed for fluorescence-guided resection (FGR) of human malignant gliomas. Furthermore, the phototoxicity of PpIX can be utilized for photodynamic therapy (PDT) of brain tumors, which has been shown previously. Here, the absolute PpIX concentration in human brain tissue was investigated following oral ALA administration (20 mg kg(-1) b.w.). An extraction procedure was used to quantify PpIX in macroscopic tissue samples, weighing 0.013-0.214 g, obtained during FGR. The PpIX concentration was significantly higher in vital grade IV tumors (5.8 ± 4.8 μm, mean ± SD, range 0-28.2 μm, n = 8) as compared with grade III tumors (0.2 ± 0.4 μm, mean ± SD, range 0-0.9 μm, n = 4). There was also a large heterogeneity within grade IV tumors with PpIX displaying significantly lower levels in infiltration zones and necrotic regions as compared with vital tumor parts. The average PpIX concentration in vital grade IV tumor parts was in the range previously shown sufficient for PDT-induced tissue damage following irradiation. However, the feasibility of PDT for grade III brain tumors and for grade IV brain tumors displaying mainly necrotic tissue areas without solid tumor parts needs to be further investigated.
118 citations
TL;DR: This method is an efficient platform that combines the advantages of a biocompatible photosensitizer with the possibility for MRI monitoring due to the magnetic properties of the highly soluble functionalized manganese oxide nanoparticles.
Abstract: Superparamagnetic MnO nanoparticles were functionalized using a hydrophilic ligand containing protoporphyrin IX as photosensitizer. By virtue of their magnetic properties these nanoparticles may serve as contrast enhancing agents for magnetic resonance imaging (MRI), while the fluorescent target ligand protoporphyrin IX allows simultaneous tumor detection and treatment by photodynamic therapy (PDT). Caki-1 cells were incubated with these nanoparticles. Subsequent exposure to UV light lead to cell apoptosis due to photoactivation of the photosensitizer conjugated to the nanoparticles. This method offers great diagnostic potential for highly proliferative tissues, including tumors. In addition, it is an efficient platform that combines the advantages of a biocompatible photosensitizer with the possibility for MRI monitoring due to the magnetic properties of the highly soluble functionalized manganese oxide nanoparticles.
77 citations
TL;DR: It is demonstrated that slr1790 encodes a unique Protox enzyme and a proposed name is proposed for this gene, which is distantly related to the M subunit of NADH dehydrogenase complex I.
Abstract: Protoporphyrinogen oxidase (Protox) catalyses the oxidation of protoporphyrinogen IX to protoporphyrin IX during the synthesis of tetrapyrrole molecules. Protox is encoded by the hemY gene in eukaryotes and by the hemG gene in many γ-proteobacteria, including Escherichia coli. It has been suggested that other bacteria possess a yet unidentified type of Protox. To identify a unique bacterial gene encoding Protox, we first introduced the Arabidopsis hemY gene into the genome of the cyanobacterium, Synechocystis sp. PCC6803. We subsequently mutagenized the cells by transposon tagging and screened the tagged lines for mutants that were sensitive to acifluorfen, which is a specific inhibitor of the hemY-type Protox. Several cell lines containing the tagged slr1790 locus exhibited acifluorfen sensitivity. The slr1790 gene encodes a putative membrane-spanning protein that is distantly related to the M subunit of NADH dehydrogenase complex I. We attempted to disrupt this gene in the wild-type background of Synechocystis, but we were only able to obtain heteroplasmic disruptants. These cells accumulated a substantial amount of protoporphyrin IX, suggesting that the slr1790 gene is essential for growth and Protox activity of cells. We found that most cyanobacteria and many other bacteria possess slr1790 homologs. We overexpressed an slr1790 homolog of Rhodobacter sphaeroides in Escherichia coli and found that this recombinant protein possesses Protox activity in vitro. These results collectively demonstrate that slr1790 encodes a unique Protox enzyme and we propose naming the slr1790 gene “hemJ.”
71 citations
TL;DR: It is concluded that this new efflux regulon controls intracellular heme and PPIX availability in S. agalactiae, and is needed for its capacity to undergo respiration metabolism, and to infect the host.
Abstract: Streptococcus agalactiae is a major neonatal pathogen whose infectious route involves septicemia. This pathogen does not synthesize heme, but scavenges it from blood to activate a respiration metabolism, which increases bacterial cell density and is required for full virulence. Factors that regulate heme pools in S. agalactiae are unknown. Here we report that one main strategy of heme and protoporphyrin IX (PPIX) homeostasis in S. agalactiae is based on a regulated system of efflux using two newly characterized operons, gbs1753 gbs1752 (called pefA pefB), and gbs1402 gbs1401 gbs1400 (called pefR pefC pefD), where pef stands for ‘porphyrin-regulated efflux’. In vitro and in vivo data show that PefR, a MarR-superfamily protein, is a repressor of both operons. Heme or PPIX both alleviate PefR-mediated repression. We show that bacteria inactivated for both Pef efflux systems display accrued sensitivity to these porphyrins, and give evidence that they accumulate intracellularly. The ΔpefR mutant, in which both pef operons are up-regulated, is defective for heme-dependent respiration, and attenuated for virulence. We conclude that this new efflux regulon controls intracellular heme and PPIX availability in S. agalactiae, and is needed for its capacity to undergo respiration metabolism, and to infect the host.
63 citations
TL;DR: The capability of a non‐invasive fluorescence imaging system to monitor changes in PpIX during real time methyl‐aminolevulinate PDT in dermatological lesions is assessed and thus to act as a predictive tool in terms of observed clinical outcome post‐treatment is assessed.
Abstract: Background and Objective
The relationship between protoporphyrin IX (PpIX) photobleaching and cellular damage during aminolevulinic (ALA) photodynamic therapy (PDT) has been studied at the cellular level. This study assessed the capability of a non-invasive fluorescence imaging system (Dyaderm, Biocam, Germany), to monitor changes in PpIX during real time methyl-aminolevulinate (MAL) PDT in dermatological lesions, and thus to act as a predictive tool in terms of observed clinical outcome post-treatment.
Materials and Methods
Patients attending Royal Cornwall Hospital (Truro, UK) for MAL-PDT to licensed lesions (actinic keratosis, Bowen's disease, and basal cell carcinoma) were monitored using the pre-validated non-invasive fluorescence imaging system. Patients were imaged at three distinct time points: prior to the application of MAL, after the 3 hours of MAL application and immediately following light irradiation. The fluorescence intensity of the images were analysed with image analysis software and the percentage change in fluorescence during light irradiation was related to the clinical outcome observed 3 months following treatment. In total 100 patients underwent at least one session of MAL-PDT.
Results
Significantly higher levels of change in PpIX fluorescence during light irradiation (P 0.500) was observed in the total levels of PpIX recorded after MAL application in patients undergoing partial and complete clearance at 3 months.
Conclusions
PpIX photobleaching is indicative of the level of cellular damage PDT treatment will induce and therefore the clinical outcome expected within patients. This study indicated the potential of the commercially available fluorescence imaging system investigated to predict treatment success at the time of light irradiation and in the future it may be possible to employ it to individualise treatment parameters to improve dermatological PDT efficacy/outcome. Lasers Surg. Med. 42:613–619, 2010. © 2010 Wiley-Liss, Inc.
55 citations
TL;DR: The structure shows that the AF molecule binds to a new site outside the previously identified inhibitor binding pocket, and reveals that the larger substrate binding chamber and predominantly positively charged chamber surface of bsPPO are more favorable for the binding of coproporphyrinogen-III.
53 citations
TL;DR: The present results strongly suggest that Pp IX silica nanoparticles may be involved in new alternative local applications of PDT, highlighting a high selectivity for tumor tissues.
Abstract: Protoporphyrin IX (Pp IX) silica nanoparticles, developed for effective use in photodynamic therapy (PDT), were explored in in vitro and in vivo models with the ambition to improve knowledge on the role of biological factors in the photodamage. Pp IX silica nanoparticles are found efficient at temperature with extreme metabolic downregulation, which suggest a high proportion of passive internalization. For the first time, clearance of silica nanoparticles on tumor cells is established. Cell viability assessment in six tumor cell lines is reported. In all tumor types, Pp IX silica nanoparticles are more efficient than free Pp IX. A strong fluorescence signal of reactive oxygen species generation colocalized with Pp IX silica nanoparticles, correlates with 100% of cell death. In vivo studies performed in HCT 116, A549 and glioblastoma multiforme tumors-bearing mice show tumor uptake of Pp IX silica nanoparticles with better tumor accumulation than the control alone, highlighting a high selectivity for tumor tissues. As observed in in vitro tests, tumor cell type is likely a major determinant but tumor microenvironment could more influence this differential time accumulation dynamic. The present results strongly suggest that Pp IX silica nanoparticles may be involved in new alternative local applications of PDT.
TL;DR: It is concluded that with further study CP94 may be a useful adjuvant to photodiagnosis and/or PpIX‐induced PDT treatment of glioma.
Abstract: Photodynamic therapy (PDT) with the pro-drugs 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) utilizes the combined interaction of a photosensitizer, light and molecular oxygen to ablate tumor tissue. To potentially increase accumulation of the photosensitizer, protoporphyrin IX (PpIX), within tumor cells an iron chelator can be employed. This study analyzed the effects of ALA/MAL-induced PDT combined with the iron chelator 1, 2-diethyl-3-hydroxypyridin-4-one hydrochloride (CP94) on the accumulation of PpIX in human glioma cells in vitro. Cells were incubated for 0, 3 and 6h with various concentrations of ALA/MAL with or without CP94 and the resulting accumulations of PpIX, which naturally fluoresces, were quantified prior to and following light irradiation. In addition, counts of viable cells were recorded. The use of CP94 in combination with ALA/MAL produced significant enhancements of PpIX fluorescence in human glioma cells. At the highest concentrations of each prodrug, CP94 enhanced PpIX fluorescence significantly at 3h for ALA and by more than 50% at 6h for MAL. Cells subsequently treated with ALA/MAL-induced PDT in combination with CP94 produced the greatest cytotoxicity. It is therefore concluded that with further study CP94 may be a useful adjuvant to photodiagnosis and/or PpIX-induced PDT treatment of glioma.
TL;DR: Investigation of nitric oxide released from a chemical donor and the range of protein targets suggest that NO can act as a global inhibitor of heme insertion, possibly by inhibiting a common step in the process.
TL;DR: Results indicate that iron chelation therapy could significantly increase δ‐ALA‐induced PpIX fluorescence in malignant gliomas, pointing to a potential role of iron chelated therapy for more effective FGR of brain tumors.
Abstract: Exogenous administration of delta-aminolevulinic acid (delta-ALA) leads to selective accumulation of protoporphyrin IX (PpIX) in brain tumors, and has shown promising results in increasing extent of resection in fluorescence-guided resection (FGR) of brain tumors. However, this approach still suffers from heterogeneous staining and so some tumor margins may go undetected because of this variation in PpIX production. The aim of this study was to test the hypothesis that iron chelation therapy could increase the level of fluorescence in malignant glioma tumors. Mice implanted with xenograft U251-GFP glioma tumor cells were given a 200 mg kg(-1) dose of deferoxamine (DFO), once a day for 3 days prior to delta-ALA administration. The PpIX fluorescence observed in the tumor regions was 1.9 times the background in animal group without DFO, and 2.9 times the background on average, in the DFO pre-treated group. A 50% increase in PpIX fluorescence contrast in the DFO group was observed relative to the control group (t-test P-value = 0.0020). These results indicate that iron chelation therapy could significantly increase delta-ALA-induced PpIX fluorescence in malignant gliomas, pointing to a potential role of iron chelation therapy for more effective FGR of brain tumors.
TL;DR: Of these compounds, B(12)H(11)NH(2) (2-)-conjugated porphyrin induced a significant increase in the level of boron accumulation and PDT efficacy against HeLa cells.
Abstract: A novel series of boronated porphyrins for potential use in boron neutron capture therapy (BNCT) and photodynamic therapy (PDT) for tumor suppression is described. Protoporphyrin IX {i.e., bis(alpha-methyl-beta-pentylethylether)protoporphyrin IX, and bis(alpha-methyl-beta-dodecanylethylether)protoporphyrin IX} bearing polyhedral borane anions (B(12)H(11)SH(2-), B(12)H(11)NH(3) (-), or B(12)H(11)OH(2-)) were synthesized with reasonable yields. Modification of the protoporphyrin IX structure was achieved by variation of the lengths of the alkyl chains (pentyl and dodecanyl) attached through ether linkages to the former vinyl groups. The goal of this modification was to develop boronated porphyrins with chemical and physical properties that differed from those of protoporphyrin IX. Performance of an MTT assay with each derivative revealed that the synthesized boronated porphyrins showed low cytotoxicities in a variety of cancer cells. Of these compounds, B(12)H(11)NH(2) (2-)-conjugated porphyrin induced a significant increase in the level of boron accumulation and PDT efficacy against HeLa cells.
TL;DR: Fluorescence spectral imaging of ALA-treated breast cancer cells showed preferential PpIX accumulation regardless of malignant phenotype and suggests a useful contrast mechanism for discrimination of residual cancer at the surface of breast tumor margins.
Abstract: We describe the potential of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence as a source of contrast for margin detection in commonly diagnosed breast cancer subtypes. Fluorescence intensity of PpIX in untreated and ALA-treated normal mammary epithelial and breast cancer cell lines of varying estrogen receptor expression were quantitatively imaged with confocal microscopy. Percentage change in fluorescence intensity integrated over 610-700 nm (attributed to PpIX) of posttreated compared to pretreated cells showed statistically significant differences between four breast cancer and two normal mammary epithelial cell lines. However, a direct comparison of post-treatment PpIX fluorescence intensities showed no differences between breast cancer and normal mammary epithelial cell lines due to confounding effects by endogenous fluorescence from flavin adenine dinucleotide (FAD). Clinically, it is impractical to obtain pre- and post-treatment images. Thus, spectral imaging was demonstrated as a means to remove the effects of endogenous FAD fluorescence allowing for discrimination between post-treatment PpIX fluorescence of four breast cancer and two normal mammary epithelial cell lines. Fluorescence spectral imaging of ALA-treated breast cancer cells showed preferential PpIX accumulation regardless of malignant phenotype and suggests a useful contrast mechanism for discrimination of residual cancer at the surface of breast tumor margins.
TL;DR: In this paper, the microstructure and magnetic properties of magnetic nanoparticles were characterized by XRD, TEM, FT-IR, and VSM, and it was found that the nanoparticles have high crystallinity with distinct lattices and the magnetic measurements reveal their well-defined superparamagnetic behavior at room temperature.
TL;DR: The linear kinetics of accumulation suggest that shorter ALA application times may be efficacious in many patients, and noninvasive fluorescence monitoring of Ppix may be useful to delineate areas of high PpIX accumulation within precancerous areas of the skin.
Abstract: Topical 5-aminolevulinic acid (ALA) is widely used in photodynamic therapy (PDT) of actinic keratoses (AK), a type of premalignant skin lesion. However, the optimal time between ALA application and exposure to light has not been carefully investigated. Our objective is to study the kinetics of protoporphyrin IX (PpIX) accumulation in AK after short contact ALA and relate this to erythemal responses. Using a noninvasive dosimeter, PpIX fluorescence measurements (5 replicates) were taken at 20-min intervals for 2 h following ALA application, in 63 AK in 20 patients. Data were analyzed for maximal fluorescent signal obtained, kinetic slope, and changes in erythema. Our results show that PpIX accumulation was linear over time, becoming statistically higher than background in 48% of all lesions by 20 min, 92% of lesions by 1 h, and 100% of lesions by 2 h. PpIX accumulation was roughly correlated with changes in lesional erythema post-PDT. We conclude that significant amounts of PpIX are produced in all AK lesions by 2 h. The linear kinetics of accumulation suggest that shorter ALA application times may be efficacious in many patients. Noninvasive fluorescence monitoring of PpIX may be useful to delineate areas of high PpIX accumulation within precancerous areas of the skin.
TL;DR: It is suggested that endo- and ex-PpIX in S180 cells differ not only in pharmacokinetics but also in sub-cellular localizations, which may affect their sonodynamic efficacy and mechanisms of inducing cell death.
TL;DR: Methyl-ALA-PDT could be an effective treatment in ovarian cancer and should be tested to apply intraperitoneally disseminated micro-foci during surgery, and is due to induction of apoptosis and reduction of angiogenesis.
Abstract: Photodynamic therapy (PDT) is a new approach to cancer treatment that utilizes photochemical reactions induced by a combination of an oncophilic photosensitizing agent and laser light. With an aim to apply PDT for intraperitoneal disseminated foci of advanced or recurrent ovarian cancers, the present study was conducted to evaluate the antitumor effect of PDT using a methyl ester of 5-aminolevulinic acid (Methyl-ALA) on various types of human ovarian cancer in a subcutaneous xenograft model in nude mice and to elucidate the mechanism of its antitumor effect. HTOA, MCAS, and TOV21G cell lines derived from human ovarian serous, mucinous, and clear cell adenocarcinoma, respectively, were used in this study. The mice in the treatment group and in the control group received an intraperitoneal injection of 250 mg/kg of Methyl-ALA and PBS alone, respectively. PDT was administered by 10 min irradiation using a 150 W halogen light, 3 h after Methyl-ALA or PBS injection. Each mouse received PDT twice a week for 3 weeks. Methyl-ALA-PDT significantly suppressed the growth of HTOA tumors as compared to control, whereas there was no significant effect on the growth of MCAS or TOV21G tumors. Methyl-ALA-PDT significantly increased apoptosis in implanted HTOA tumors as well as cultured cells. Western blot analysis showed that amount of expression of milk fat globule-EGF-factor 8, which binds to apoptotic cells and thereby facilitates their phagocytosis, significantly increased in HTOA tumors receiving Methyl-ALA-PDT, compared with untreated HTOA tumors. In addition, reduced vascular endothelial growth factor and CD34-positive microvessel density were found in solid HTOA tumors treated by Methyl-ALA-PDT, suggesting that the antitumor effect of Methyl-ALA-PDT is due to induction of apoptosis and reduction of angiogenesis. In comparison with HTOA cells, HPLC analysis demonstrated a significantly smaller intracellular amount of protoporphyrin IX (PpIX) in MCAS and TOV21G cells. PpIX is readily converted from Methyl-ALA and elicts photocytotoxicity. We conclude that Methyl-ALA-PDT could be an effective treatment in ovarian cancer and should be tested to apply intraperitoneally disseminated micro-foci during surgery.
TL;DR: A conclusion that Hep2c cell line is sensitive to ALA-mediated PDT is concluded with a conclusion that sensitizer or light doses have no significant effect on cells viability when studied independently.
Abstract: 5-aminolevulanic acid (ALA), a precursor of Protoporphyrin IX, was evaluated as an inducer of photodamage on Hep2c, human larynx squamous cell carcinoma, cell line. Porphyrins are used as active cytotoxic antitumor agents in photodynamic therapy (PDT). The present study evaluates the effects of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) using human larynx cells as experimental model. Hep2c cell line was irradiated with red light (a diode laser, λ = 635 nm). The influence of different incubation times and concentrations of 5-ALA, different irradiation doses and various combinations of photosensitizer and light doses on the cellular viability of Hep2c cells were studied. The optimal uptake of photosensitizer ALA in Hep-2c cells was investigated by means of spectrometric measurement. Cells viability was determined by means of neutral red assay (NR). It was observed that sensitizer or light doses have no significant effect on cells viability when studied independently. The spectrometric measurements showed that the maximal cellular uptake of 5-ALA occurred after 7 h in vitro incubation. The photocytotoxic assay showed that light dose of 85 J/cm2 gives effective PDT outcome for Hep2c cell line incubated with 55 μg/ml of 5-ALA with a conclusion that Hep2c cell line is sensitive to ALA-mediated PDT.
TL;DR: A high frequency ultrasound-coupled fluorescence tomography system, primarily designed for imaging of protoporphyrin IX production in skin tumors in vivo, is demonstrated for the first time.
Abstract: A high frequency ultrasound-coupled fluorescence tomography system, primarily designed for imaging of protoporphyrin IX production in skin tumors in vivo, is demonstrated for the first time. The design couples fiber-based spectral sampling of the protoporphyrin IX fluorescence emission with high frequency ultrasound imaging, allowing thin-layer fluorescence intensities to be quantified. The system measurements are obtained by serial illumination of four linear source locations, with parallel detection at each of five interspersed detection locations, providing 20 overlapping measures of subsurface fluorescence from both superficial and deep locations in the ultrasound field. Tissue layers are defined from the segmented ultrasound images and diffusion theory used to estimate the fluorescence in these layers. The system calibration is presented with simulation and phantom validation of the system in multilayer regions. Pilot in-vivo data are also presented, showing recovery of subcutaneous tumor tissue values of protoporphyrin IX in a subcutaneous U251 tumor, which has less fluorescence than the skin.
TL;DR: Photocytotoxicity was shown to be highly correlated with membrane affinity, which depends on the asymmetrical and amphiphilic characters of sens, as well as with sub-cellular localization.
Abstract: Protoporphyrin (Pp IX) derivatives were prepared to study the relationship between photosensitizer structure and photoactivity, with an emphasis on understanding the role of membrane interactions in the efficiency of photosensitizers used in photodynamic therapy (PDT). The synthetic strategies described here aimed at changing protoporphyrin periferic groups, varying overall charge and oil/water partition, while maintaining their photochemical properties. Three synthetic routes were used: (1) modification of Pp IX at positions 31 and 81 by addition of alkyl amine groups of different lengths (compounds 2–5), (2) change of Pp IX at positions 133 and 173, generating alkyl amines (compounds 6 and 7, a phosphate amine (compound 8, and quarternary ammonium compounds (compounds 9 and 10), and (3) amine-alkylation of Hematoporphyrin IX (Hp IX) at positions 31, 81, 133 and 173(compound 12). Strategy 1 leads to hydrophobic compounds with low photocytotoxicity. Strategy 2 leads to compounds 6–10 that have high levels of binding/incorporation in vesicles, mitochondria and cells, which are indicative of high bioavailability. Addition of the phosphate group (compound 8), generates an anionic compound that has low liposome and cell incorporation, plus low photocytotoxicity. Compound 12 has intermediate incorporation and photocytotoxic properties. Compound modification is also associated with changes in their sub-cellular localization: 30% of 8 (anionic) is found in mitochondria as compared to 95% of compound 10 (cationic). Photocytotoxicity was shown to be highly correlated with membrane affinity, which depends on the asymmetrical and amphiphilic characters of sens, as well as with sub-cellular localization.
TL;DR: A new, serendipitous, preparation step was found for Fe(II) porphyrins, in the gas phase by femtosecond pump-probe spectroscopy, interpreted as an ultrafast charge transfer from the porphirin excited orbital π* to a vacant d orbital on the iron atom.
Abstract: The time evolution of electronically excited heme (iron II protoporphyrin IX, [FeII PP]) and its associated salt hemin (iron III protoporphyrin IX chloride, [FeIII PP–Cl]), has been investigated for the first time in the gas phase by femtosecond pump–probe spectroscopy. The porphyrins were excited at 400 nm in the S2 state (Soret band) and their relaxation dynamics was probed by multiphoton ionization at 800 nm. This time evolution was compared with that of the excited state of zinc protoporphyrin IX [Zn PP] whose S2 excited state likely decays to the long lived S1 state through a conical intersection, in less than 100 fs. Instead, for [FeII PP] and [FeIII PP–Cl], the key relaxation step from S2 is interpreted as an ultrafast charge transfer from the porphyrin excited orbital π* to a vacant d orbital on the iron atom (ligand to metal charge transfer, LMCT). This intermediate LMCT state then relaxes to the ground state within 250 fs. Through this work a new, serendipitous, preparation step was found for FeII porphyrins, in the gas phase.
TL;DR: The results indicated that the synergistic cytotoxicity of Ppix and ultrasound increased in a time-dependent manner and the mitochondria damage may be the main factor for sonodynamically induced apoptosis by PpIX in H22 cells.
Abstract: The synergistic effect of ultrasound and certain chemicals on cells is known as sonodynamic therapy (SDT). It has been reported that the direct sonochemical and subsequent redox reactions induced by SDT treatment can lead to apoptotic cell death. However, the detailed biologic mechanism about it is not well understood until now. In this study the effect of low-intensity ultrasound on Hepatoma-22 cells (H22) in the presence of the sonosensitizing drug protoporphyrin IX (PpIX) was evaluated at different incubation times after sonication. Trypan blue exclusion was used to detect cell viability. The presence of apoptotic cells was identified by 4'-6-diamidino-2-phenylindole (DAPI) nuclear staining and transmission electric microscope (TEM) observation. An inverted confocal laser scanning microscope was used to detect the release of mitochondrial protein cytochrome c (Cyt c) and the redistribution of Bcl-2 family proteins Bid and Bax. Additionally, the generation of intracellular reactive oxygen species (ROS) and the loss of mitochondria membrane potential (MMP) were quantificationally measured by a fluorescence microplate reader. The results indicated that the synergistic cytotoxicity of PpIX and ultrasound increased in a time-dependent manner and the mitochondria damage may be the main factor for sonodynamically induced apoptosis by PpIX in H22 cells.
TL;DR: The potential of using endogenous phorphyrin blood fluorescence as tumour marker for prostate cancer is explored using fluorescence and excitation spectroscopy on healthy male NUDE mice and in those with prostate cancer induced by inoculation of DU145 cells.
Abstract: Prostate cancer is one of the most common types of cancer in men, and unfortunately many prostate tumours remain asymptomatic until they reach advanced stages. Diagnosis is typically performed through Prostate-Specific Antigen (PSA) quantification, Digital Rectal Examination (DRE) and Transrectal Ultrasonography (TU). The antigen (PSA) is secreted by all prostatic epithelial cells and not exclusively by cancerous ones, so its concentration also increases in the presence of other prostatic diseases. DRE and TU are not reliable for early detection, when histological analysis of prostate tissue obtained from a biopsy is necessary. In this context, fluorescence techniques are very important for the diagnosis of cancer. In this paper we explore the potential of using endogenous phorphyrin blood fluorescence as tumour marker for prostate cancer. Substances such as porphyrin derivatives accumulate substantially more in tumours than in normal tissues; thus, measuring blood porphyrin concentration by autofluorescence intensity may provide a good parameter for determining tumour stage. In this study, the autofluorescence of blood porphyrin was analyzed using fluorescence and excitation spectroscopy on healthy male NUDE mice and in those with prostate cancer induced by inoculation of DU145 cells. A significant contrast between the blood of normal and cancer subjects could be established. Blood porphyrin fluorophore showed an enhancement on the fluorescence band around 632 nm following tumour growth. Fluorescence detection has advantages over other light-based investigation methods: high sensitivity, high speed and safety. However it does carry the drawback of low specificity of detection. The extraction of blood porphyrin using acetone can solve this problem, since optical excitation of further molecular species can be excluded, and light scattering from blood samples is negligible.
TL;DR: A simple and rapid approach based on non-linear variable-angle synchronous fluorescence spectrometry coupled with partial least squares analysis (NLVASF/PLS) was developed for the simultaneous determination of porphyrins in whole blood and the differential diagnosis of porphyria.
TL;DR: Results suggest that BchJ may play a role as a general magnesium porphyrin carrier, similar to one of the roles of GUN4 in oxygenic organisms.
Abstract: Substrate channeling between the enzymatic steps in the (bacterio)chlorophyll biosynthetic pathway catalyzed by magnesium chelatase (BchI/ChlI, BchD/ChlD and BchH/ChlH subunits) and S-adenosyl-L-methionine:magnesium-protoporphyrin IX O-methyltransferase (BchM/ChlM) has been suggested. This involves delivery of magnesium-protoporphyrin IX from the BchH/ChlH subunit of magnesium chelatase to BchM/ChlM. Stimulation of BchM/ChlM activity by BchH/ChlH has previously been shown, and physical interaction of the two proteins has been demonstrated. In plants and cyanobacteria, there is an added layer of complexity, as Gun4 serves as a porphyrin (protoporphyrin IX and magnesium-protoporphyrin IX) carrier, but this protein does not exist in anoxygenic photosynthetic bacteria. BchJ may play a similar role to Gun4 in Rhodobacter, as it has no currently assigned function in the established pathway. Purified recombinant Rhodobacter capsulatus BchJ and BchM were found to cause a shift in the equilibrium amount of Mg-protoporphyrin IX formed in a magnesium chelatase assay. Analysis of this shift revealed that it was always in a 1 : 1 ratio with either of these proteins and the BchH subunit of the magnesium chelatase. The establishment of the new equilibrium was faster with BchM than with BchJ in a coupled magnesium chelatase assay. BchJ bound magnesium-protoporphyrin IX or formed a ternary complex with BchH and magnesium-protoporphyrin IX. These results suggest that BchJ may play a role as a general magnesium porphyrin carrier, similar to one of the roles of GUN4 in oxygenic organisms.
TL;DR: It was found that DFO had different potentials for augmenting ALA-PDT in these cutaneous cell lines, and the cells proliferating more rapidly might be more susceptible to enhancement of DFO.
Abstract: Protoporphyrin IX (PpIX) is the photosensitizer in 5-aminolaevulinic acid (ALA)-based photodynamic therapy (PDT). Its further bioconversion to heme requires iron and can be suppressed by iron chelators such as desferrioxamine (DFO). To investigate the effectiveness of DFO in enhancing PpIX-based PDT in skin tissue, we selected fibroblasts, HaCat cells and Hep-2 cells as targets co-cultured with ALA, that have different biological characteristics for PpIX conversion. Evaluated interventions included: (1) blank control (no ALA, no DFO); (2) DFO alone; (3) ALA alone; and (4) DFO in combination with ALA. Before photodynamic irradiation, cellular PpIX level and fluorescence were measured. After irradiation, cell death ratio was calculated and morphological changes in the cells were observed. The results showed that the content and photodynamic effects of cellular PpIX presented in the order Hep-2 cells > HaCat cells > fibroblasts, either co-cultured with ALA alone or with ALA plus DFO. DFO was found to have increasing effects on both PpIX level and cell death ratio in the same order. It was found that DFO had different potentials for augmenting ALA-PDT in these cutaneous cell lines. The cells proliferating more rapidly might be more susceptible to enhancement of DFO.
TL;DR: Investigation of how temperature change varied the therapeutic effect of ALA‐based PDT in vitro found that increasing skin temperature could improve 5‐aminolevulinic acid penetration and accumulation of protoporphyrin IX.
Abstract: Background/purpose Based on the observation that increasing skin temperature could improve 5-aminolevulinic acid (ALA) penetration and accumulation of protoporphyrin IX (PpIX) in the ALA-based photodynamic therapy (PDT), this study was designed to investigate how temperature change varied the therapeutic effect of ALA-based PDT in vitro. Methods HaCat cells were cultured with or without ALA at various temperatures. ALA uptake and PpIX accumulation were analyzed before laser irradiation as the baseline. After irradiation, cell death and cytokine secretions in the media, including interleukin (IL)-1alpha, tumor necrosis factor (TNF)-alpha and basic fibroblast growth factor (bFGF) were assayed, and the morphological changes were recorded. Results With increasing temperature, the amount of ALA uptake, intracellular PpIX concentration and cell death increased in both the PDT and the non-PDT groups. Secretions of IL-1alpha, TNF-alpha and bFGF also increased and reached a peak around 44-47 degrees C and then declined at a higher temperature. This biphasic response might be due to protein thermolysis that occurs when cells reach beyond thermal tolerance. Conclusions Elevating temperature could augment photodynamic reactions to a certain extent, but adverse effects occurred when cells were overheated.