Reposicionamento de fármacos no câncer de boca: Identificação de possíveis agentes / Drug repositioning for oral cancer: Identifying candidate therapeutic agents

O objetivo deste estudo foi o de identificar compostos seletivamente tóxicos ao carcinoma espinocelular de boca in vitro por meio do reposicionamento de fármacos. Material e Métodos: Por meio de um escaneamento baseado na viabilidade celular de 1.280 fármacos, nós selecionamos três princípios ativos (luteolin, metixene hydrochloride e nitazoxanide) letais às células de câncer de boca SCC-25 e pouco tóxicos às células de queratinócitos cutâneos imortalizados HaCaT. Os fármacos candidatos foram investigados quanto à sua dose- e tempo-resposta bem como comparados e combinados à agentes quimioterápicos padrão por meio do ensaio por colorimetria com brometo de tiazolil azul de tetrazolio (MTT). O impacto dos fármacos na motilidade do SCC-25 e do HaCaT foi verificado pelo ensaio de migração celular e seus mecanismos de ação também foram explorados por meio da verificação dos níveis das proteínas fosforiladas pelo western blotting. Todos os experimentos foram realizados em triplicata e, pelo menos, três vezes independentes. O teste t de student foi utilizado para confrontar as variáveis e nível de significância de 5% foi estabelecido para todos os testes. Resultados: O flavonoide natural luteolin exerceu citotoxicidade potente contra as células de câncer de boca in vitro, apresentando baixa toxicidade ao HaCaT e alta eficiência quando comparado a quimioterápicos como a cisplatina e o AG1478. Do ponto de vista molecular, a luteolin ativou a via de sinalização do dano do DNA e, combinada com um inibidor do Chk, apresentou efeitos potencializados. Além disso, nós demonstramos que a nitazoxanide e o metixene hydrochloride são capazes de destruir células SCC-25 porém não as HaCaT de maneira proporcional à dose e ao tempo de tratamento. As combinações entre os três fármacos hit e com a cisplatina ou o AG1478 potencializaram seus efeitos contra as células malignas. Conclusões: O presente estudo traz a luteolin, o metixene hydrochloride e a nitazoxanide como...

Here we aimed at identifying and reposition approved drugs that could be selectively toxic towards oral squamous cell carcinoma cells. Materials and Methods: Through a cell-based drug screening of 1,280 chemical molecules, we selected 3 compounds (luteolin, metixene hydrochloride, and nitazoxanide) lethal to oral cancer SCC-25 cells, while sparing immortalized keratinocyte HaCaT cells. The drugs were then further challenged for their time- and dose-responses, as well as their comparison and combination to standard chemotherapeutic agents by colorimetric assay 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan, Thiazolyl blue formazan (MTT). The impact on SCC-25 and HaCaT motility as well as the mode of action of the drugs was then further explored by scratching assay and western blotting, respectively. All the experiments were performed in triplicated and, at least, three independent times. Students t test was performed to verify the differences among the variables and the level of significance was set at 5%. Results: The natural flavonoid luteolin was a potent cytotoxic agent against oral cancer cells in vitro, presenting low toxicity against HaCaT cells and high efficiency as compared to standard-of-care, such as cisplatin and AG1478. From a molecular standpoint, luteolin coopted the DNA-damage pathway and could be efficiently combined with Chk pharmacological inhibitor. Moreover, we demonstrated that nitazoxanide and metixene hydrochloride kill the SCC-25 but not the HaCaT cells in a dose- and time-dependent. The combinations among the three drugs hit and with cisplatin and AG1478 improved their effect against the malignant cells. Conclusions: Luteolin, metixene hydrochloride, and nitazoxanide emerge as strong cytotoxic and/or adjuvant therapy in oral cancer, as these compounds present higher efficiency and lower toxicity against oral cancer cells in vitro than conventional chemotherapeutic agents...

Reposicionamento de fármacos no câncer de boca: Identificação de possíveis agentes / Drug repositioning for oral cancer: Identifying candidate therapeutic agents

Objetivos: O objetivo deste estudo foi o de identificar compostos seletivamente tóxicos ao carcinoma espinocelular de boca in vitro por meio do reposicionamento de fármacos. Material e Métodos: Por meio de um escaneamento baseado na viabilidade celular de 1.280 fármacos, nós selecionamos três princípios ativos (luteolin, metixene hydrochloride e nitazoxanide) letais às células de câncer de boca SCC-25 e pouco tóxicos às células de queratinócitos cutâneos imortalizados HaCaT. Os fármacos candidatos foram investigados quanto à sua dose- e tempo-resposta bem como comparados e combinados à agentes quimioterápicos padrão por meio do ensaio por colorimetria com brometo de tiazolil azul de tetrazolio (MTT). O impacto dos fármacos na motilidade do SCC-25 e do HaCaT foi verificado pelo ensaio de migração celular e seus mecanismos de ação também foram explorados por meio da verificação dos níveis das proteínas fosforiladas pelo western blotting. Todos os experimentos foram realizados em triplicata e, pelo menos, três vezes independentes. O teste t de student foi utilizado para confrontar as variáveis e nível de significância de 5% foi estabelecido para todos os testes. Resultados: O flavonoide natural luteolin exerceu citotoxicidade potente contra as células de câncer de boca in vitro, apresentando baixa toxicidade ao HaCaT e alta eficiência quando comparado a quimioterápicos como a cisplatina e o AG1478. Do ponto de vista molecular, a luteolin ativou a via de sinalização do dano do DNA e, combinada com um inibidor do Chk, apresentou efeitos potencializados. Além disso, nós demonstramos que a nitazoxanide e o metixene hydrochloride são capazes de destruir células SCC-25 porém não as HaCaT de maneira proporcional à dose e ao tempo de tratamento. As combinações entre os três fármacos hit e com a cisplatina ou o AG1478 potencializaram seus efeitos contra as células malignas. Conclusões: O presente estudo traz a luteolin, o metixene hydrochloride e a nitazoxanide como...

Objectives: Here we aimed at identifying and reposition approved drugs that could be selectively toxic towards oral squamous cell carcinoma cells. Materials and Methods: Through a cell-based drug screening of 1,280 chemical molecules, we selected 3 compounds (luteolin, metixene hydrochloride, and nitazoxanide) lethal to oral cancer SCC-25 cells, while sparing immortalized keratinocyte HaCaT cells. The drugs were then further challenged for their time- and dose-responses, as well as their comparison and combination to standard chemotherapeutic agents by colorimetric assay 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan, Thiazolyl blue formazan (MTT). The impact on SCC-25 and HaCaT motility as well as the mode of action of the drugs was then further explored by scratching assay and western blotting, respectively. All the experiments were performed in triplicated and, at least, three independent times. Students t test was performed to verify the differences among the variables and the level of significance was set at 5%. Results: The natural flavonoid luteolin was a potent cytotoxic agent against oral cancer cells in vitro, presenting low toxicity against HaCaT cells and high efficiency as compared to standard-of-care, such as cisplatin and AG1478. From a molecular standpoint, luteolin coopted the DNA-damage pathway and could be efficiently combined with Chk pharmacological inhibitor. Moreover, we demonstrated that nitazoxanide and metixene hydrochloride kill the SCC-25 but not the HaCaT cells in a dose- and time-dependent. The combinations among the three drugs hit and with cisplatin and AG1478 improved their effect against the malignant cells. Conclusions: Luteolin, metixene hydrochloride, and nitazoxanide emerge as strong cytotoxic and/or adjuvant therapy in oral cancer, as these compounds present higher efficiency and lower toxicity against oral cancer cells in vitro than conventional chemotherapeutic agents.

Polymerization kinetics and reactivity of alternative initiators systems for use in light-activated dental resins.

OBJECTIVES: The purpose of this study was to evaluate the reactivity and polymerization kinetics behavior of a model dental adhesive resin with water-soluble initiator systems. METHODS: A monomer blend based on Bis-GMA, TEGDMA and HEMA was used as a model dental adhesive resin, which was polymerized using a thioxanthone type (QTX) as a photoinitiator. Binary and ternary photoinitiator systems were formulated using 1mol% of each initiator. The co-initiators used in this study were ethyl 4-dimethylaminobenzoate (EDAB), diphenyliodonium hexafluorophosphate (DPIHFP), 1,3-diethyl-2-thiobarbituric acid (BARB), p-toluenesulfinic acid and sodium salt hydrate (SULF). Absorption spectra of the initiators were measured using a UV-Vis spectrophotometer, and the photon absorption energy (PAE) was calculated. The binary system camphorquinone (CQ)/amine was used as a reference group (control). Twelve groups were tested in triplicate. Fourier-transform infrared spectroscopy (FTIR) was used to investigate the polymerization reaction during the photoactivation period to obtain the degree of conversion (DC) and maximum polymerization rate (R(p)(max)) profile of the model resin. RESULTS: In the analyzed absorption profiles, the absorption spectrum of QTX is almost entirely localized in the UV region, whereas that of CQ is in the visible range. With respect to binary systems, CQ+EDAB exhibited higher DC and R(p)(max) values. In formulations that contained ternary initiator systems, the group CQ+QTX+EDAB was the only one of the investigated experimental groups that exhibited an R(p)(max) value greater than that of CQ+EDAB. The groups QTX+EDAB+DPIHFP and QTX+DPIHFP+SULF exhibited values similar to those of CQ+EDAB with respect to the final DC; however, they also exhibited lower reactivity. SIGNIFICANCE: Water-soluble initiator systems should be considered as alternatives to the widely used CQ/amine system in dentin adhesive formulations.

Comparative EST transcript profiling of peach fruits under different post-harvest conditions reveals candidate genes associated with peach fruit quality.

BACKGROUND: Cold storage is used to inhibit peach fruit ripening during shipment to distant markets. However, this cold storage can negatively affect the quality of the fruit when it is ripened, resulting in disorders such as wooliness, browning or leathering. In order to understand the individual and combined biological effects that factors such as cold storage and ripening have on the fruit and fruit quality, we have taken a comparative EST transcript profiling approach to identify genes that are differentially expressed in response to these factors. RESULTS: We sequenced 50,625 Expressed Sequence Tags (ESTs) from peach mesocarp (Prunus persica O'Henry variety) stored at four different postharvest conditions. A total of 10,830 Unigenes (4,169 contigs and 6,661 singletons) were formed by assembling these ESTs. Additionally, a collection of 614 full-length and 1,109 putative full-length cDNA clones within flanking loxP recombination sites was created. Statistically analyzing the EST population, we have identified genes that are differentially expressed during ripening, in response to cold storage or the combined effects of cold storage and ripening. Pair-wise comparisons revealed 197 contigs with at least one significant difference in transcript abundance between at least two conditions. Gene expression profile analyses revealed that the contigs may be classified into 13 different clusters of gene expression patterns. These clusters include groups of contigs that increase or decrease transcript abundance during ripening, in response to cold or ripening plus cold. CONCLUSION: These analyses have enabled us to statistically identify novel genes and gene clusters that are differentially expressed in response to post-harvest factors such as long-term cold storage, ripening or a combination of these two factors. These differentially expressed genes reveal the complex biological processes that are associated with these factors, as well as a large number of putative gene families that may participate differentially in these processes. In particular, these analyzes suggest that woolly fruits lack the increased boost of metabolic processes necessary for ripening. Additionally, these results suggest that the mitochondria and plastids play a major role in these processes. The EST sequences and full-length cDNA clones developed in this work, combined with the large population of differentially expressed genes may serve as useful tools and markers that will enable the scientific community to better define the molecular processes that affect fruit quality in response to post-harvest conditions and the organelles that participate in these processes.

Relationship between mast cells and the colitis with relapse induced by trinitrobenzesulphonic acid in Wistar rats.

The present study aimed to clarify the role of mast cells in colitis with relapse induced in Wistar rats by trinitrobenzenosulphonic acid. Colitis induction increased the histamine concentration in the colon, which peaked on day 26. The number of mast cells, probably immature, was ten times higher on day 8. Different from animals infected with intestinal parasites, after colitis remission, mast cells do not migrate to the spleen, showing that mast cell proliferation presents different characteristics depending on the inflammation stimuli. Treatment with sulfasalazine, doxantrazole, quercetin, or nedocromil did not increase the histamine concentration or the mast cell number in the colon on day 26, thereby showing absence of degranulation of these cells. In conclusion, although mast cell proliferation is associated with colitis, these cells and their mediators appear to play no clear role in the colitis with relapses.

Cinqüenta anos de medicamentos antipsicóticos em psiquiatria: III. fenotiazinas piperidínicas / Fifty years of antipsychotic drugs in psychiatry: III. piperidine phenothiazines

Na iminência de uma nova era na terapêutica psiquiátrica com a redescoberta da clozapina e a introduçäo dos novos antipsicóticos atípicos, é tempo de um inventário das substâncias desenvolvidas nos últimos cinqüenta anos. É feito um breve histórico dos antecedentes dos antipsicóticos tradicionais na era que se encerra. As substâncias introduzidas até o presente poderiam ser reunidas nos grupos tradicionais - fenotiazinas (alifáticas, piperazínicas e piperidínicas), tioxantenos, butirofenonas, difenilbutilpiperidinas, benzaminas, indóis, dibenzoxazepinas - e nos grupos químicos mais recentes - diidroindolonas, dbenzodiazepinas, benzisoxazólicos -, além de compostos ainda em desenvolvimento. Neste artigo, o terceiro de uma série concebida com esta finalidade, säo examinados os derivados fenotiazínicos com cadeia lateral piperidínica que tenham demonstrado utilidade na prática clínica e ou guardem importância histórica: mepazina, mesoridazina, nortioridazina, piperacetazina, propericiazina, sulforidazina e toridazina. Com base em bibliografia básica específica, säo discutidos aspectos técnicos e revisado o conhecimento científico acumulado através da experimentaçäo e utilizaçäo clínica destes compostos, desde seu lançamento até a presente data, com informaçöes sistemáticas sobre fórmula estrutural, fórmula molecular, nomes químicos, nomes de fantasia e códigos de cada composto, além de dados sobre eventual comercializaçäo no país

Resistance of schistosomes to hycanthone and oxamniquine.

Genetic crosses between phenotypically resistant and sensitive schistosomes demonstrated that resistance to hycanthone and oxamniquine behaves like a recessive trait, thus suggesting that resistance is due to the lack of some factor. We hypothesized that, in order to kill schistosomes, hycanthone and oxamniquine need to be converted into an active metabolite by some parasite enzyme which, if inactive, results in drug resistance. Esterification of the drugs seemed to be the most likely event as it would lead to the production of an alkylating agent upon dissociation of the ester. An artificial ester of hycanthone was indeed active even in resistant worms, thus indirectly supporting our hypothesis. In addition, several lines of evidence demonstrated that exposure to hycanthone and oxamniquine results in alkylation of worm macromolecules. Thus, radioactive drugs formed covalent bonds with the DNA of sensitive (but not of resistant) schistosomes; an antiserum raised against hycanthone detected the presence of the drug in the purified DNA fraction of sensitive (but not of resistant) schistosomes; a drug-DNA adduct was isolated from hycanthone-treated worms and fully characterized as hycanthone-deoxyguanosine.

Schistosoma mansoni-induced mesangiocapillary glomerulonephritis: influence of therapy.

Schistosomiasis mansoni has been well documented as one of the causes of infectious glomerulopathy, with mesangiocapillary glomerulonephritis being the most frequent lesion observed in this condition. Twenty-one patients with hepatosplenic schistosomiasis mansoni and biopsy-documented mesangiocapillary glomerulonephritis (MCGN) were studied and compared with 19 patients with the idiopathic form of MCGN. Nephrotic syndrome was the most frequent clinical presentation in both groups. At the time of diagnosis nine patients with hepatosplenomegaly (4 with associated arterial hypertension) and 12 (8 with arterial hypertension) among the patients with idiopathic MCGN had renal insufficiency. At the end of the follow-up period 16 patients with hepatosplenic schistosomiasis and MCGN (75.2 months) and 15 with the idiopathic form (52.1 months) had renal failure. Also, when compared at 48 months of follow-up, no difference in renal function could be detected in both groups. No benefits related to anti-parasitic treatment in the schistosomiasis group and immunosuppression therapy in either group could be documented. The progression of the renal disease, as assessed by the reciprocal of serum creatinine versus time, and the survival curve, were not different between the two groups. It is concluded that MCGN in patients with the hepatosplenic form of schistosomiasis mansoni is a progressive disease not influenced by anti-parasitic or immunosuppressive therapy, and presents a clinical course similar to that of the idiopathic form.

Citoprotección gástrica por cromoglicato disódico y RS-7540 / Gastric cytoprotection by disodiu chromoglycate and RS-7540

Se estudió el efecto de la droga RS-7540 sobre la secreción gástrica en ratas sometidas a ligadura del piloro por una hora. Se comparó, con la utilización de dosis equimolares (2,0. 10 mol/kg) la acción del CGDS con li de la droga RS-7540 en el modelo de inducción de lesiones por etanol al 96

Se encontró que la droga RS-7540 no inhibió significativamente el volumen ni la acidez de la secreción gástrica y protegió la mucosa gástrica de las lesiones inducidas por etanol al 96

, por lo que tiene un efecto citoprotector. No existen diferencias significativas sobre el efecto citoprotector de la droga RS-7540 y del cromoglicato disódico. La administración simultánea de ambas drogas no aumenta la protección de la mucosa gástrica

Citoprotección gástrica por cromoglicato disódico y RS-7540 / Gastric cytoprotection by disodium chromoglycate and RS-7540

Se estudió el efecto de la droga RS-7540 sobre la secreción gástrica en ratas sometidas a ligadura del piloro por una hora. Se comparó, con la utilización de dosis equimolares (2,0. 10 mol/kg) la acción del CGDS con li de la droga RS-7540 en el modelo de inducción de lesiones por etanol al 96% Se encontró que la droga RS-7540 no inhibió significativamente el volumen ni la acidez de la secreción gástrica y protegió la mucosa gástrica de las lesiones inducidas por etanol al 96%, por lo que tiene un efecto citoprotector. No existen diferencias significativas sobre el efecto citoprotector de la droga RS-7540 y del cromoglicato disódico. La administración simultánea de ambas drogas no aumenta la protección de la mucosa gástrica

Anti-schistosomal drugs: observations on the mechanism of drug resistance to hycanthone, and on the involvement of host antibodies in the mode of action of praziquantel.

This paper reports recent observations from our laboratory dealing with the anti-schistosome drugs hycanthone (HC) and praziquantel (PZQ). In particular, we discuss a laboratory model of drug resistance to HC in Schistosoma mansoni and show that drug sensitive and resistant lines of the parasite can be differentiated on the basis of restriction fragment length polymorphisms using homologous ribosomal gene probes. In addition, we summarize data demonstrating that effective chemotherapy of S. mansoni infection with PZQ in mice requires the presence of host anti-parasite antibodies. These antibodies bind to PZQ treated worms and may be involved in an antibody-dependent cellular cytotoxicity reactions which result in the clearance of worms from the vasculature.

Immediate hypersensitivity reactions in epithelia from rats infected with Nippostrongylus brasiliensis.

Colonic epithelia from rats infected with the nematode Nippostrongylus brasiliensis have been studied under short circuit conditions and in response to challenge with worm antigen. Challenge from the serosal but not the mucosal side with antigen caused a transient increase in inwardly directed short circuit current. No effects were observed in comparable tissues from noninfected animals. Simultaneous measurements of short circuit current and of the fluxes of sodium or chloride ions showed there was an increase in electrogenic chloride secretion and an inhibition of electroneutral sodium chloride absorption, associated with antigen challenge. This result, together with the inhibitory effects of piretanide on the response to antigen challenge, indicate that chloride ions are a major carrier of the short circuit current response. However, the equivalence of the biophysical response to ion fluxes was not established, there being an excess of chloride secretion. The mast cell stabilizing agent, FPL 52694, significantly inhibited the current responses to antigen, while cromoglycate and doxantrazole were ineffective. Mepyramine, an H1-receptor antagonist, and indomethacin, an inhibitor of fatty acid cyclo-oxygenase, were without effect on the responses to antigen challenge. Anti-rat IgE produced qualitatively similar responses to antigen in both normal and sensitized colonic epithelia. However, the responses were significantly greater in tissues derived from infected animals. Maximally effective antigen concentrations prevented subsequent responses to anti-rat IgE in sensitized tissues, while anti-rat IgE only attenuated the responses to antigen. The ways in which antigen challenge modifies epithelial function is discussed, particularly in relation to its possible role in promoting rejection of the nematodes during secondary infection.

[Drug therapy of mansoni schistosomiasis]. / Tratamento medicamentoso da esquistossomose mansoni.

The various presentations of schistosomiasis mansoni are discussed, stressing the indications of parosites elimination. Parasitologic cure is necessary, although, when the infestation is recent (acute), the drug efficacy is lower than in the chronic forms. Surgery may be pertension, special care must be taken, and in the pseudotumoral form there is not enough diet regarding progression of the disease after treatment. Contraindications are linked to associated illness, and are due to toxic effects of the available drugs. The mechanism of action of such drugs are discussed, as well as the historical background. Hycantone, Oxamniquine and Praziquantel are detailed in separate, with the proposed drug schedules and possible side effects.

Control of Schistosoma mansoni transmission by chemotherapy in St. Lucia. I. Results in man.

Control of Schistosoma mansoni transmission solely by treatment of all infected persons was attempted in Marquis Valley (population about 3,100), St. Lucia. Two-year results are reported. Excluding 26 pregnant patients, 709 to 729 persons who were found to be infected received treatment the first year. Most of these, 677, were given a single injection of hycanthone (2.5 mg/kg of body weight), and the same treatment was administered to 159 patients the second year. Side effects were not severe; the major side effect, vomiting, occurred in about 22% on both occasions. In villages with initially high transmission rates, the incidence of new infections in children 0 to 14 years fell from 20.8% before chemotherapy to 7.4% after 1 year and to 3.7% after 2 years. This pattern was significantly different from that in the comparison area where no control scheme exists. Chemotherapy alone appears to be a rapid, effective, and comparatively inexpensive method of controlling S. mansoni transmission in St. Lucia.

Control of Schistosoma mansoni transmission by chemotherapy in St. Lucia. I. Results in man

Control of Schistosoma mansoni transmission solely by treatment of all infected persons was attempted in Marquis Valley (population about 3,100), St. Lucia. Two-year results are reported. Excluding 26 pregnant patients, 709 of 729 persons who were found to be infected received treatment the first year. Most of these, 677, were given a single injection of hyacanthone (2.5 mg/kg of body weight), and the same treatment was administered to 159 patients the second year. Side effects were not severe; the major side effect, vomiting, occurred in about 22 percent on both occassions. In villages with initially high transmission rates, the incidence of new infections in children 0 to 14 years fell from 20.8 percent before chemotherapy to 7.4 percent after 1 year and to 3.7 percent after 2 years. This pattern was significantly different from that in the comparison area where no control scheme exists. Chemotherapy alone appears to ba a rapid, effective, and comparatively inexpensive method of controlling S. mansoni transmission in St. Lucia (AU)