RESUMO
Frataxin plays a key role in cellular iron homeostasis of different organisms. It is engaged in several activities at the FeS cluster assembly machinery and it is also involved in heme biosynthesis. In plants, two genes encoding ferrochelatases (FC1 and FC2) catalyze the incorporation of iron into protoporphyrin IX in the last stage of heme synthesis in chloroplasts. Despite ferrochelatases are absent from other cell compartments, a remaining ferrochelatase activity has been observed in plant mitochondria. Here we analyze the possibility that frataxin acts as the iron donor to protoporphyrin IX for the synthesis of heme groups in plant mitochondria. Our findings show that frataxin catalyzes the formation of heme in vitro when it is incubated with iron and protoporphyrin IX. When frataxin is combined with AtNFS1 and AtISD11 the ferrochelatse activity is increased. These results suggest that frataxin could be the iron donor in the final step of heme synthesis in plant mitochondria, and constitutes an important advance in the elucidation of the mechanisms of heme synthesis in plants.
Assuntos
Proteínas de Arabidopsis/metabolismo , Ferroquelatase/metabolismo , Proteínas de Ligação ao Ferro/metabolismo , Mitocôndrias/enzimologia , Arabidopsis , Proteínas de Arabidopsis/química , Catálise , Cloroplastos/enzimologia , Ferroquelatase/química , Heme/biossíntese , Proteínas de Ligação ao Ferro/química , Protoporfirinas/biossínteseRESUMO
Renal cell carcinoma (RCC) remains one of the greatest challenges of urological oncology and is the third leading cause of death in genitourinary cancers. Surgery may be curative when patients present with localized disease. Our previous results demonstrated the autofluorescence of blood PpIX in primary RCC mouse model and an increase in fluorescence intensity as a function of growth of the subcutaneous tumor mass. In another work, a nice correlation between the growth of the tumor mass and tissue fluorescence intensity was found. The aim of this study was to evaluate the expression profile of porphyrin biosynthesis pathway-related genes of human kidney cells. We used two kidney cell lines, one normal (HK2) and another malignant (Caki-1). Endogenous and 5-aminolevolinic acid (ALA) induced protoporphyrin IX (PpIX) HK2 and Caki-1 cells were analyzed by fluorescence spectroscopy. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to measure mRNA of those genes. Emission spectra were obtained by exciting the samples at 405 nm. For ALA untreated cells the maximum fluorescence intensity was detected at 635 nm. The mean peak area of emission spectra in both cells types increased linearly in function of cell number. Besides, basal levels of PpIX autofluorescence of each cell concentration of HK2 samples were significantly lower than those of Caki-1 samples. For ALA-treated cells the mean PpIX spectra shows PpIX emission peak at 635 nm with a shoulder at 700 nm. Analysis of PpIX fluorescence intensity ratio between tumor cells and HK2 cells showed that fluorescence intensity was, on average, 26 times greater in tumor cells than in healthy cells. qRT-PCR revealed that in Caki-1 ALA-treated cells, PEPT gene was significantly up-regulated and FECH and HO-1 genes were significantly down regulated in comparison with HK2 ALA-treated cells. In conclusion, our results demonstrate the preferential accumulation of ALA-induced PpIX in human RCC and also indicate that PEPT1, FECH and HO-1 genes are major contributors to this accumulation.
Assuntos
Carcinoma de Células Renais/patologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Renais/patologia , Protoporfirinas/biossíntese , Animais , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Linhagem Celular Tumoral , Humanos , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Camundongos , Protoporfirinas/metabolismoRESUMO
OBJECTIVE: The goal of this study is to demonstrate an alternative procedure to perform topical photodynamic therapy (PDT). Here, we propose the combined use of negative pressure and a 5-Aminolevulinic acid (5-ALA) cream occlusion to increase protoporphyrin IX (PPIX) formation. BACKGROUND DATA: PDT using topical 5-ALA as a prodrug and precursor of PPIX has been used in the treatment and diagnosis of different types of cancer and skin diseases. The use of 5-ALA offers many advantages as a localized and non-systemic application, but it shows limitations in relation to skin penetration. Many authors have discussed the limitations of 5-ALA penetration through the skin. The skin penetration of 5-ALA can be optimized using mechanical devices associated with typical PDT procedure. METHODS: For this study, 20% 5-ALA cream was applied to a 9 cm(2) area of skin, and an occlusive dressing was placed. The PPIX production was collected at the skin surface, using fluorescence spectroscopy and widefield fluorescence imaging, for 7 h, and after 24 h. RESULTS: We observed that in the presence of negative pressure therapy, the PPIX production, distribution, and elimination are greater and faster than in the control group. The PPIX formation was â¼30% in deeper skin layers, quantified by fluorescence spectroscopy analysis, and â¼20% in surface skin layers, quantified by widefield fluorescence imaging analysis. CONCLUSIONS: Negative pressure induction can also help PDT application in the case of inefficient PPIX production. These results can be useful for optimizing the PDT.
Assuntos
Tratamento de Ferimentos com Pressão Negativa , Fotoquimioterapia/métodos , Ácido Aminolevulínico/administração & dosagem , Humanos , Protoporfirinas/biossíntese , Creme para a PeleRESUMO
This paper describes the elimination of porphyrins by feces. It was demonstrated that porphyrin accumulates substantially more in tumors than in normal tissues, and consequently more PPIX reaches the blood of patients and animals with tumors, and then, it needs to be eliminated. The fluorescence of feces revealed that there are large amounts of PPIX in the excreta of animals with cancer comparing with healthy animals. The autofluorescence of feces porphyrin extracted with acetone was analyzed using fluorescence spectroscopy of animals inoculated with DU145 cells into the prostate and healthy animals to monitor the PPIX concentration. Emission spectra were obtained by exciting the samples at 405 nm. Significant differences were observed in autofluorescence intensities measured in the 575-725 nm spectral regions for the studied groups. The results showed a noninvasive, simple, rapid and sensitive method to detect cancer by feces analysis.
Assuntos
Técnicas e Procedimentos Diagnósticos , Fezes/química , Neoplasias da Próstata/patologia , Protoporfirinas/metabolismo , Animais , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/metabolismo , Protoporfirinas/biossíntese , Espectrometria de FluorescênciaRESUMO
A fluorometric analytical method was developed for quantification of protoporphyrin IX (PpIX) in skin samples and receptor phase solution after in vitro cutaneous penetration/permeation studies. Analytical conditions used were: excitation and emission wavelengths: 400 nm and 632 nm; bandwidth: 0.5 nm; excitation and emission slits: 10/10. PpIX was recovered from two different layers of skin, the stratum corneum (SC) and the epidermis plus dermis ([E+D]), by vortex homogenization, probe and bath sonication, using DMSO as an extraction solvent. The detection and quantification limits were 0.002 and 0.005 μg/mL, respectively. The assay was linear from 0.005 - 0.5 μg/mL. The within-day and between-day assay precision and accuracy in DMSO and receptor phase solution were each studied at the two concentration levels 0.04 and 0.2 μg/mL, and 0.01 and 0.08 μg/mL, respectively. The coefficients of variation and deviation from the theoretical values were lower than 5%. The skin recovery of PpIX from SC and [E+D] layers using two different concentrations (0.5 and 1.0 μg/mL) were all above 90.0%. The method described has potential application to in vitro penetration/permeation studies of PpIX using porcine skin as a biological membrane model.
Um método analítico por espectrofluorimetria foi desenvolvido para quantificar a protoporfirina IX (Pp IX) em amostras de pele e fase receptora após a realização de testes in vitro de penetração/permeação cutâneas. As condições analíticas utilizadas foram: comprimentos de onda de excitação e emissão: 400 nm e 632 nm; largura de banda: 0,5 nm; fendas de excitação e emissão: 10/10. A PpIX foi extraída de amostras de estrato córneo (EC) e da epiderme sem estrato córneo + derme ([E+D]) através da agitação em vórtex e sonicação por haste e banho, utilizando-se o DMSO como solvente extrator. O limite de detecção e quantificação foram, respectivamente, de 0,002 e 0,005 μg/mL. O método mostrou-se linear da faixa de 0,005 - 0,5 μg/mL. A precisão e exatidão intra e inter-ensaio em DMSO e na fase receptora foram validadas utilizando-se duas concentrações distintas, respectivamente, de 0,004 e 0,2 μg/mL, e 0,01 e 0,08 μg/mL. Os valores de coeficiente de variação e o desvio do valor teórico foram inferiores a 5%. A recuperação da PpIX das camadas da pele (EC e [E+D]) utilizando-se duas concentrações distintas (0,5 e 1,0 μg/mL) foram todas acima de 90,0%. O método descrito pode ser utilizado para determinação da PpIX após estudos de penetração/permeação cutânea in vitro utilizando pele de porco como modelo de membrana.
Assuntos
Absorção Cutânea , Espectrometria de Fluorescência/métodos , Técnicas In Vitro , Protoporfirinas/biossíntese , Protoporfirinas/química , Bioensaio/métodos , PeleRESUMO
Photodynamic therapy (PDT) may cause tumour cell destruction by direct toxicity or by inducing microcirculatory shutdown. Protoporphyrin IX generated from 5-aminolevulinic acid (ALA) has been widely used as an endogenous photosensitiser in PDT. However, the hydrophilic nature of the ALA molecule limits its penetration through the stratum corneum of the skin and cell membranes and thus, ALA alkyl-esters have been developed to improve ALA permeation. The aim of this work was to study Protoporphyrin IX synthesis from ALA and its derivatives ALA methyl ester (Me-ALA) and ALA hexyl ester (He-ALA) in the microvascular endothelial cell line HMEC-1 derived from normal skin, and to evaluate their response to PDT. We found that lower light doses are required to photosensitise HMEC-1 endothelial cells than to photosensitise PAM212 transformed keratinocytes, showing some possible selectivity of ALA-PDT for vascularisation in skin. Employed at concentrations leading to equal Protoporphyrin IX synthesis, ALA, He-ALA and Me-ALA presented the same efficacy of HMEC-1 photosensitisation. However, He-ALA was a promising compound for the use in the enhancement of Protoporphyrin IX in HMEC-1 cells employed at low concentrations at both short and long time exposures whereas Me-ALA should be employed at high concentrations and longer time periods in order to surpass the Protoporphyrin IX levels obtained with ALA. The advantage of Me-ALA over ALA was based on its lower dark toxicity. This is the first work to report vascular cell photosensitisation employing alkyl-esters of ALA, and we demonstrated that these derivatives could exert the same effect as ALA and under certain conditions enhance photosensitisation of vasculature.
Assuntos
Ácido Aminolevulínico/análogos & derivados , Ácido Aminolevulínico/metabolismo , Células Endoteliais/metabolismo , Fotoquimioterapia , Fármacos Fotossensibilizantes/metabolismo , Protoporfirinas/biossíntese , Animais , Linhagem Celular , Células Endoteliais/efeitos da radiação , Humanos , Protoporfirinas/fisiologia , Raios UltravioletaRESUMO
The use of endogenous protoporphyrin IX (PpIX) after administration of 5-aminolaevulinic acid (ALA) has led to many applications in photodynamic therapy (PDT). However the efficacy of ALA-PDT is sub-optimal for thicker tumours and improved ALA delivery and therapeutic response are required. We have investigated the conjugation of ALA to a second-generation dxcendrimer for enhancing porphyrin synthesis in vitro and in vivo in a murine tumour model using systemic i.p. administration. In vitro, the dendrimer was more efficient than ALA for porphyrin synthesis at low concentrations in good correlation with higher cellular ALA dendrimer accumulation. In vivo, the porphyrin kinetics from ALA exhibited an early peak between 3 and 4 h in most tissues, whereas the dendrimer induced sustained porphyrin production for over 24 h and basal values were not reached until 48 h after administration. Integrated porphyrin accumulation from the dendrimer and ALA, at equivalent molar ratios, was comparable showing that the majority of ALA residues were liberated from the dendrimer. The porphyrin kinetics appear to be governed by the rate of enzymatic cleavage of ALA from the dendrimer, which is consistent with in vitro results. ALA dendrimers may be useful for metronomic PDT, and multiple low-dose ALA-PDT treatments.
Assuntos
Ácido Aminolevulínico/farmacologia , Dendrímeros/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/uso terapêutico , Porfirinas/metabolismo , Adenocarcinoma/tratamento farmacológico , Ácido Aminolevulínico/administração & dosagem , Ácido Aminolevulínico/química , Ácido Aminolevulínico/metabolismo , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Corantes/metabolismo , Dendrímeros/síntese química , Relação Dose-Resposta a Droga , Injeções Subcutâneas , Masculino , Neoplasias Mamárias Experimentais/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Peso Molecular , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/metabolismo , Protoporfirinas/biossíntese , Relação Estrutura-Atividade , Sais de Tetrazólio/metabolismo , Tiazóis/metabolismo , Fatores de Tempo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The cytotoxic effect of 5-aminolevulinic acid (ALA) induced protoporphyrin IX (PPIX) on two human carcinoma cell lines, MCF-7c3 cells and Hep 2 cells, was studied. In both cell lines, PPIX content depends on the ALA concentration and incubation time. The maximal PPIX content was higher in the MCF-7c3 cells, reaching a value of 8 microg/10(6) cells, compared to the Hep-2 cells, which accumulated 3.2 microg/10(6) cells. Treatment of cells with the iron chelator desferrioxamine prior to ALA exposure enhances the amount of PPIX, consequently diminishing enzymatic activity of ferroquelatase. Photo sensitization of the cells was in correlation with the PPIX content; therefore, conditions leading to 80% cell death in the MCF-7c3 cells provoke a 50% cell death in the Hep 2 cells. Using fluorescence microscopy, cell morphology was analyzed after incubation with 1 mM ALA during 5 hr and irradiation with 54 Jcm(-2); 24 hr post-PDT, MCF-7c3 cells revealed the typical morphological changes of necrosis. Under the same conditions, Hep-2 cells produced chromatine fragmentation characteristic of apoptosis. PPIX accumulation was observed to occur in a perinuclear region in the MCF-7c3 cells; while in Hep-2 cells, it was localized in lysosomes. Different mechanisms of cell death were observed in both cell lines, depending on the different intracellular localization of PPIX.
Assuntos
Adenocarcinoma/tratamento farmacológico , Ácido Aminolevulínico/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Adenocarcinoma/metabolismo , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Desferroxamina/farmacologia , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Sinergismo Farmacológico , Humanos , Luz , Neoplasias Hepáticas/metabolismo , Microscopia de Fluorescência , Protoporfirinas/biossínteseRESUMO
Photodynamic therapy (PDT), a potential therapy for cancer treatment, utilizes exogenously applied or endogenously formed photosensitizers, further activated by light in an appropriate wavelength and dose to induce cell death through free radical formation. 5-Aminolevulinic acid (5-ALA) is a pro-drug which can be converted to the effective photosensitizer, protoporphyrin IX (PpIX). However, the use of 5-ALA in PDT is limited by the low penetration capacity of this highly hydrophilic molecule into appropriate skin layers. In the present study, we propose to increase 5-ALA penetration by using formulations containing glycerol monooleate (GMO), an interesting and useful component of pharmaceutical formulations. Propylene glycol solutions containing different concentrations of GMO significantly increased the in vitro skin permeation/retention of 5-ALA in comparison to control solutions. In vivo studies also showed increased PpIX accumulation in mouse hairless skin, after the use of topical 5-ALA formulations containing GMO in a concentration-dependent manner. The results show that skin 5-ALA penetration and PpIX accumulation, important factors for the success of topical 5-ALA-PDT in skin cancer, are optimized by GMO/propylene glycol formulations.
Assuntos
Ácido Aminolevulínico/farmacocinética , Glicerídeos/farmacologia , Propilenoglicol/química , Protoporfirinas/biossíntese , Absorção Cutânea/efeitos dos fármacos , Pele/metabolismo , Administração Cutânea , Ácido Aminolevulínico/administração & dosagem , Ácido Aminolevulínico/química , Ácido Aminolevulínico/farmacologia , Animais , Química Farmacêutica , Glicerídeos/administração & dosagem , Glicerídeos/química , Técnicas In Vitro , Masculino , Camundongos , Camundongos Pelados , RatosRESUMO
The use of 5-aminolevulinic acid (5-ALA) ester derivatives as precursors of endogenous protoporphyrin IX (PpIX) has been proposed as a good strategy for improved drug diffusion across biological membranes. In the present work, the 5-ALA ester derivatives hexyl-ALA (h-ALA), octyl-ALA (o-ALA), and decyl-ALA (d-ALA) were synthesized, and their efficacy to induce endogenous PpIX was explored in a murine melanoma cell line (B-16) as compared with that of 5-ALA. The maximum level of PpIX induced in cells treated with 5-ALA, h-ALA, o-ALA, and d-ALA was reached at optimal concentrations of 0.3, 0.075, 0.1, and 0.075 mM, respectively. The derivatives h-ALA and o-ALA appear as the most efficient PpIX precursors in this cell line, since a higher or similar PpIX production could be achieved with a fourfold and threefold lower dose of these precursors compared with 5-ALA. The phototoxicity effect of h-ALA and o-ALA ester derivatives showed the same phototoxicity behavior detected for 5-ALA but at much lower drug doses. Our study suggests that h-ALA and o-ALA esters improve intracellular PpIX formation in B-16 cells at reduced concentrations. This should enable clinical applications at lower precursor doses with reduced effective costs.
Assuntos
Ácido Aminolevulínico/farmacologia , Melanoma/tratamento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Protoporfirinas/biossíntese , Animais , Difusão , Relação Dose-Resposta a Droga , Espectroscopia de Ressonância Magnética , Camundongos , Microscopia de Fluorescência , Células Tumorais CultivadasRESUMO
Exogenous administration of 5-aminolevulinic acid (ALA) is becoming widely used to enhance the endogenous synthesis of Protoporphyrin IX (PpIX) in photodynamic therapy. We analysed porphyrin formation in chemically induced squamous papillomas, after topical application of ALA and ALA hexyl ester (He-ALA) administered in different formulations, as well as the pattern of distribution in the internal organs, and the synthesis of porphyrins in distant tumoural and normal skins. A lotion formulation containing DMSO and ethanol was the best vehicle for topical ALA delivery to papillomas, whereas cream was the most efficient formulation for He-ALA application. Similar porphyrin concentration can be accumulated in the skin tumours employing either ALA or He-ALA delivered in their optimal formulations. The use of cream as a vehicle of both ALA and He-ALA, induces highest porphyrin tumour/normal skin ratios. The main advantage of using He-ALA is that porphyrins synthesized from the ester are more confined to the site of application, thus inducing low porphyrin levels in normal skin, liver, blood and spleen, as well as in papillomas distant from the point of application, independently on the vehicle employed, so reducing potential side effects of photodynamic therapy.
Assuntos
Ácido Aminolevulínico/análogos & derivados , Ácido Aminolevulínico/farmacologia , Papiloma/metabolismo , Protoporfirinas/biossíntese , Neoplasias Cutâneas/metabolismo , 9,10-Dimetil-1,2-benzantraceno , Animais , Feminino , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Papiloma/química , Papiloma/tratamento farmacológico , Fotoquimioterapia/métodos , Protoporfirinas/sangue , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Neoplasias Cutâneas/induzido quimicamente , Neoplasias Cutâneas/tratamento farmacológico , Baço/efeitos dos fármacos , Baço/metabolismoRESUMO
Samples of human and rat skin in short-term organ culture exposed to ALA or a range of hydrophobic derivatives were examined for their effect on the accumulation of protoporphyrin IX (PpIX) measured using fluorescence spectroscopy. With the exception of carbobenzoyloxy-D-phenylalanyl-5-ALA-ethyl ester the data presented indicate that, in normal tissues, ALA derivatives generate protoporphyrin IX more slowly than ALA, suggesting that they are less rapidly taken up and/or converted to free ALA. However, the resultant depot effect may lead to the enhanced accumulation of porphyrin over long exposure periods, particularly in the case of ALA-methyl ester or ALA-hexyl ester, depending on the applied concentration and the exposed tissue. Addition of the iron chelator, CP94, greatly increased PpIX accumulation in human skin exposed to ALA, ALA-methyl ester and ALA-hexyl ester. The effect in rat skin was less marked.
Assuntos
Ácido Aminolevulínico/farmacologia , Protoporfirinas/biossíntese , Pele/efeitos dos fármacos , Ácido Aminolevulínico/análogos & derivados , Animais , Feminino , Humanos , Microscopia de Fluorescência , Técnicas de Cultura de Órgãos , Ratos , Ratos Wistar , Pele/metabolismoRESUMO
BACKGROUND: delta-Aminolevulinic acid (ALA) is recognized as the starter in the biosynthesis of the heme group, the structural basis of cytochromes, chlorophylls, biliary pigments, and other porphyrins. It is the first intermediary in the biosynthesis of protoporphyrin IX (PpIX), and of the heme group. PpIX is present in low concentration in normal cells, and in high concentration in tumor cells. METHODS: The accumulation of protoporphyrin IX (PpIX) induced by delta-aminolevulinic acid (ALA) was tested in two cervico-uterine cancer cell lines (HeLa and CaLo), and in normal human cervical epithelial (NHCE) cells. RESULTS: The optimal concentration of ALA that induced maximum levels of intra- and extracellular accumulation of PpIX in both HeLa and NHCE cells was 300 micrograms of ALA/mL, and for CaLo cells, 150 micrograms/mL. The viability of HeLa, CaLo, and NHCE cells exposed to ALA measured 81, 98, and 84%, respectively. The optimal time for accumulation of PpIX, both intra- and extracellular, was 4 h for HeLa and NHCE cells and 5 h for CaLo cells per 24 h of exposure to optimal concentrations of ALA. After the maximum level of PpIX accumulation was reached, there was a gradual decrease until there was only a small quantity. A statistically significant difference (p < 0.0001) was found in the accumulation of PpIX, depending on the concentrations of ALA used as well as between cervical cancer cell lines and NHCE cells (p < 0.0001). The concentration ratio of PpIX for NHCE and HeLa cells was 1:7, and for NHCE and CaLo cells, 1:5. CONCLUSIONS: These results are important for determining the usefulness of the sensitizer (PpIX).
Assuntos
Ácido Aminolevulínico/farmacologia , Colo do Útero/efeitos dos fármacos , Fármacos Fotossensibilizantes/metabolismo , Protoporfirinas/biossíntese , Neoplasias do Colo do Útero/tratamento farmacológico , Linhagem Celular , Colo do Útero/citologia , Colo do Útero/metabolismo , Feminino , Células HeLa , Humanos , Células Tumorais Cultivadas , Neoplasias do Colo do Útero/patologiaRESUMO
Bxkground. Ù-Aminolevulinic acid (ALA) is recognized as the starter in the biosynthesis of the heme group, the structural basis of cytochromes, chlorophylls, biliary pigments, and other porphyrins. It is the first intermediary in the biosynthesis of protoporphyrin IX (PpIX), and of ther heme group. PpIX is present in low concentration in normal cells, and in high concentration in tumor cells. Methods. The accumulation of protoporhyrin IX (PpIX) induced by Ù-aminolevulinic acid (ALA) was tested in two cervico-uterine cancer cell lines (HeLa and CaLo), and in normal human cervical epithelial (NHCE) cells. Results. The optimal concentration of ALA that induced maximum levels of intra- and extracellular accumulation of PpIX in both HeLa and NHCE cells was 300 µg of ALA/mL, and for CaLo cells, 150 µg/mL. The viability of HeLa, CaLo, and NHCE cells exposed to ALA measured 81, 98 and 84 percent, respectively. The optimale time for accumulation of PpIX, both intra- and extracellular, was 4 h for HeLa and NHCE cells and 5 h for CaLo cells per 24 h of expusure to optimal concentrations of ALA. After the maximum level of PpIX accumulation was reached, there was a gradual decrease until there was only a small quantity. A statistically significant difference (p <0.0001) was foundf in the accumulation of PpIX, depending on the concentrations of ALA used as well as between cervical cancer cell lines and 1:7, and for NHCE and CaLo cells. 1:5. Conclusions. These results are important for determining the usefulness of the sensitizer (PpIX)
Assuntos
Humanos , Feminino , Ácido Aminolevulínico/farmacologia , Colo do Útero/efeitos dos fármacos , Colo do Útero/metabolismo , Fármacos Fotossensibilizantes/metabolismo , Protoporfirinas/biossíntese , Neoplasias do Colo do Útero/tratamento farmacológico , Linhagem Celular , Colo do Útero/citologia , Células Tumorais Cultivadas , Neoplasias do Colo do Útero/patologiaRESUMO
Acute toxic effects of lead were evaluated on porphyrin synthesis and coproporphyrinogen oxidase (CO) activity in an in vitro model, using HepG2 cells, a hepatoma cell line of human origin. Lead concentrations for exposure treatments were 0.5, 1.0, 2.5, 5.0 microM. No significant changes were found in treated cells with respect to uroporphyrin cellular or media concentrations. Cellular protoporphyrin increased in dose response shape, but no changes in extracellular content were found. Extracellular coproporphyrin concentration increased in a dose response manner without changes in cellular content. The CO activity was depressed in dose response shape, reaching 62% of control activity at 5.0 microM of lead treatment. The CO activity in Pb-treated cells was recovered after dithiothreitol (DTT) treatment, suggesting that sulphydryl groups play an essential role in the enzyme activity. The dose-response increase of coproporphyrin secretion accompanied by the depression of CO activity supports the suggestion that lead causes CO inhibition, as observed in this cellular model.
Assuntos
Coproporfirinogênio Oxidase/metabolismo , Chumbo/toxicidade , Compostos Organometálicos/toxicidade , Carcinoma Hepatocelular , Cromatografia Líquida de Alta Pressão , Coproporfirinogênio Oxidase/antagonistas & inibidores , Ditiotreitol/farmacologia , Relação Dose-Resposta a Droga , Humanos , Protoporfirinas/análise , Protoporfirinas/biossíntese , Espectrometria de Fluorescência , Reagentes de Sulfidrila/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
Actualiza los conocimientos, además muestra los adelantos en: biosíntesis de oligosacáridos, factores de crecimiento, receptores del sistema nervioso, coagulación de la sangre, membranas y bases moleculares de la inmunidad
Assuntos
Humanos , Biologia/educação , Química Orgânica/educação , Proteínas/biossíntese , Glucose/metabolismo , Lipídeos/metabolismo , Hormônios/biossíntese , Vitaminas/biossíntese , Ácidos Nucleicos/metabolismo , Enzimas/química , Protoporfirinas/biossíntese , Imunidade/fisiologia , Formação de Anticorpos/fisiologia , Glucose/biossíntese , Glucose/química , Proteínas/química , Lipídeos/biossíntese , Lipídeos/química , Hormônios , Vitaminas/química , Vitaminas/uso terapêutico , Ácidos Nucleicos/química , Enzimas/fisiologia , Protoporfirinas/metabolismoRESUMO
Actualiza los conocimientos, además muestra los adelantos en: biosíntesis de oligosacáridos, factores de crecimiento, receptores del sistema nervioso, coagulación de la sangre, membranas y bases moleculares de la inmunidad