<p> Some plants such as spinach, sugar beet, and wheat accumulate the quaternary ammonium compound glycine betaine when exposed to stresses in their environment. Environmental stress can be in the form of an excess or deficiency of water, high salt content, and/or exposure to excessively low or high temperatures and many if not all of these stresses are associated with cell dehydration. </p> <p> Glycine betaine is an organic solute that is believed to help restore the osmotic potential of a cell undergoing dehydration by reducing water loss and preventing damage to the structure and function of macromolecules. However, many plants such as Arabidopsis, tobacco, and rice do not accumulate glycine betaine. Given the perceived benefits of glycine betaine production by plants under stress, studies have been carried out to identify factors regulating its production. </p> <p> Glycine betaine is synthesized by the two-step oxidation of choline. The capacity to synthesize phosphocholine for choline production has been found to limit the production of glycine betaine in non-accumulating plants such as tobacco. As such, genetic engineering has been used to enhance the production of choline to up-regulate the synthesis of glycine betaine. This strategy has required knowledge of the enzyme(s) catalyzing the three N-methylation steps of the phosphocholine biosynthetic pathway. </p> <p> This study focused on a gene product identified as putative-phosphoethanolamine N-methyltransferase (putative PEAMT) based upon its similarity to a spinach Nmethyltransferase known to convert phosphoethanolamine to phosphocholine. This gene is located at the locus Atlg73600 on chromosome I of Arabidopsis and its predicted amino acid sequence has high similarity to two other genes encoding N-methylating enzymes located at At3 g 18000 (a biochemically confirmed PEAMT) and At 1 g48600 (annotated as a putative PEAMT). </p> <p> In this study, publicly available microarray data was examined to identify an expression profile of transcripts associated with the Atlg73600 gene in organs and tissues of Arabidopsis at various developmental stages. A summary of the micro array data shows the highest abundance of transcripts for Atlg73600 to be in the rosette leaves of Arabidopsis at 18.0- 20.9 days of growth. </p> <p> Arabidopsis plants grown from seeds from four SALK lines reported to have a TDNA insert in the Atlg73600 gene were screened for the presence of a T-DNA tag using a three primer PCR design strategy. Individual plants from two of the lines were found to have a T-DNA insert present. RT-PCR was then used to analyze the expression of transcripts associated with the Atlg73600 gene in these mutant lines. Transcripts were not detected among the amplified products from eDNA produced from the SALK line designated 062703 but they were found at reduced levels in eDNA of SALK line 016929c. </p> <p> In future studies the two T -DNA mutant lines identified in this study can be used to assign a biological role for the product of the Atlg73600 gene by examining the phenotype of these mutant plants relative to that of wild-type plants under normal and/or stressed conditions. The line found with no expression associated with the Atlg73600 gene will be useful in crosses with T -DNA knock-out mutants of genes at loci At3g18000 and Atlg48600. Systematic knock-outs for each of the genes in isolation and in combination will help discern whether there is functional redundancy in their biological roles or if their individual expression contributes uniquely towards the development of a plant or its stress response. Given the associated role for PEAMT in phosphatidylcholine metabolism, lipidomics could be used to determine if the composition of the plant membranes is altered relative to wild-type when the Atlg73600 gene is knocked-out. </p> / Thesis / Master of Science (MSc)

Neste estudo foram avaliados os efeitos antitumorais da fosfoetanolamina sintética (FS) em modelos de tumores experimentais e as vias de sinalizações envolvidas nesta atividade. In vitro a FS foi citotóxica para as linhagens de células tumorais de melanoma humano, SK-MEL-28, carcinoma renal murino RENCA e para as células do carcinoma de pulmão de não pequenas células NSCLC. Alterações ultraestruturais como a condensação da cromatina, formação de blubes de membranas e mitocôndrias eletrodensas foi acompanhada pela redução do potencial elétrico mitocondrial. Aumento da ativação da caspase 3 e 8 e da expressão da proteína Bax, além da redução da CDK9 e CDK4/6, também foram observados. A redução da migração e proliferação das células endoteliais HUVEC induzida pela FS foi associada com a modulação da expressão do VEGF-A. resultando na inibição in vitro da formação do tubo endotelial. In vivo a FS foi capaz de inibir o crescimento dos tumores sólidos do melanoma e do carcinoma renal murino de forma superior aos quimioterápicos Dacarbazina (DITC) e ao Sunitinib. No modelo de metástase pulmonar utilizando as células RENCA, a FS reduziu o número de nódulos metastáticos pulmonares e aumentou a taxa de sobrevida dos animais. Os efeitos terapêuticos da FS também foram avaliados no modelo de leucemia promielocítica aguda (LPA) transplantada em camundongos NOD/Scid. O tratamento com a FS reduziu o número de blastos periféricos e infiltrados na medula óssea e nos parênquimas, esplênico e hepático. De forma superior a Daunorrubicina (DA) e ao Ácido all-trans retinóico (ATRA), a FS induziu apoptose nos clones malignos que expressão CD34+, bem como nas células CD117+/Gr-1+. Este conjunto de resultados mostra que a FS é um composto promissor na terapêutica contra neoplasias / In this study, we evaluated the antitumor effects of synthetic phosphoethanolamine (FS) in an experimental tumor model and the signaling pathways involved in this activity. In vitro, FS was cytotoxic to tumor cell lines of human melanoma, SK- MEL-28, renal carcinoma murine, Renca, and for non-small cell lung cancer, NSCLC. Ultrastructural changes such as chromatin condensation, blubes formation on membranes and electrodense mitochondria were accompanied by a reduction of the mitochondrial electric potential. Increased activation of caspase-3, 8 and Bax protein expression, in addition to a reduction of CDK9 and CDK4/6 levels, was also observed. The reduction of migration and proliferation of endothelial cells, HUVEC, induced by FS was associated with the modulation of VEGF-A-expression, resulting in the in vitro inhibition of tubulogenesis. In vivo, FS was able to inhibit the growth of solid tumors of melanoma and renal carcinoma more potently than Dacarbazine (DITC) and Sunitinib. In the lung metastasis model, using RENCA cells, FS reduced the number of metastatic lung nodules and increased the survival rate of the animals. The therapeutic effects of FS were also evaluated in the model of acute promyelocytic leukemia transplanted in mice NOD/Scid. The treatment with FS reduced the number of peripheral blasts and infiltrates in the blood marrow, splenic and hepatic parenchyma. Fs was more potent than Daunorrubicine (DA) and all-trans retinoic acid (ATRA) in the induction of apoptosis in the malignant clones expressing CD34+ as well as CD117+/Gr-1+ cells. Taken together, theses results show that FS is a promising compound for the therapy against tumors

The anti-pneumococcal function of native C-reactive protein (CRP) involves its binding to phosphocholine molecules present on Streptococcus pneumoniae and subsequent activation of the complement system. However, when pneumococci recruit complement inhibitory protein factor H on their surface, they escape complement attack. Non-native forms of CRP have been shown to bind immobilized factor H. Accordingly, we hypothesized that modified CRP would bind to factor H on pneumococci, masking its complement inhibitory activity, allowing native CRP to exert its anti-pneumococcal function. As reported previously, native CRP protected mice from lethal pneumococcal infection when injected 30 minutes before infection but not when injected 24 hours after infection. However, a combination of native and mutant CRP was found to protect mice even when administered 24 hours after infection. Therefore, it is concluded that while native CRP is protective only against early-stage infection, a combination of native and mutant CRP offers protection against late-stage infection.

Le phosphate (Pi) est un macroélément essentiel au développement de la plante. Lors d'une carence en Pi, l'expression de plusieurs gènes est dérégulée permettant à la plante de s'adapter à ce type de stress abiotique. Chez Arabidopsis thaliana, la carence induit très fortement PS2;1 (At1g73010) et PS2;2 (At1g17710), deux phosphatases de type HAD. La fonction biochimique de ces deux protéines a été caractérisée précédemment in vitro, mais leur rôle in vivo reste à établir.Dans ce travail de thèse, nous avons examiné la fonction in planta de ces deux protéines en utilisant des approches de génétique inverse. Affecter leur niveau d'expression par surexpression ou inactivation n’a d’effet ni sur la teneur en Pi de la cellule végétale, ni sur des marqueurs classiques de la carence en Pi. Par contre, nous montrons que PS2;1 et PS2;2 assurent la dégradation de la phosphocholine et potentiellement la phosphoéthanolamine, deux composés identifiés comme substrats potentiels lors des analyses in vitro.Nos données ne suggèrent pas d’implication de PS2;1 et PS2;2 dans la dégradation du pyrophosphate, un troisième substrat potentiel proposé suites aux analyses in vitro. Nos résultats suggèrent que les deux protéines PS2;1 et PS2;2 interviennent in planta dans le remodelage des lipides membranaires déclenchés par la carence en Pi, permettant de convertir les phospholipides en galacto ou sulfolipides. Plus particulièrement, ces enzymes permettraient le recyclage du Pi des têtes polaires phosphocholine et phosphoéthanolamine, issues de la dégradation des phospholipides phosphatidylcholine et phosphatidyléthanolamine / Phosphate (Pi) is a macroelement essential to plant development. During Pi deficiency, the expression of several genes is deregulated, allowing the plant to cope with this type of abiotic stress. In Arabidopsis thaliana, Pi deficiency strongly induces PS2;1 (At1g73010) and PS2;2 (At1g17710), two HAD-type phosphatases. The biochemical functions of these two proteins were previously characterized in vitro, although their in vivo roles have not yet been established.Here, the functions of these two proteins were examined in plants using reverse genetics approaches. Overexpression or inactivation of their expression levels had no effect on the Pi content of the plant cell, or on classic markers of Pi deficiency. Furthermore, PS2;1 and PS2;2 affect phosphocholine levels in planta (and potentially phosphoethanolamine), two compounds identified as their potential substrates by in vitro assays.In contrast, these findings do not suggest any involvement of PS2;1 or PS2;2 in the degradation of pyrophosphate, another potential substrate according to previous in vitro assays. In conclusion, these results suggest that PS2;1 and PS2;2 are involved in the remodeling of membrane lipids triggered by Pi deficiency, allowing the conversion of phospholipids to galactolipids or sulfolipids. Specifically, these enzymes should allow the recycling of Pi from phosphocholine and phosphoethanolamine polar heads, byproducts of the degradation of phospholipid phosphatidylcholine and phosphatidylethanolamine

Neste estudo foram avaliados os efeitos antitumorais da fosfoetanolamina sintética (FS) em modelos de tumores experimentais e as vias de sinalizações envolvidas nesta atividade. In vitro a FS foi citotóxica para as linhagens de células tumorais de melanoma humano, SK-MEL-28, carcinoma renal murino RENCA e para as células do carcinoma de pulmão de não pequenas células NSCLC. Alterações ultraestruturais como a condensação da cromatina, formação de blubes de membranas e mitocôndrias eletrodensas foi acompanhada pela redução do potencial elétrico mitocondrial. Aumento da ativação da caspase 3 e 8 e da expressão da proteína Bax, além da redução da CDK9 e CDK4/6, também foram observados. A redução da migração e proliferação das células endoteliais HUVEC induzida pela FS foi associada com a modulação da expressão do VEGF-A. resultando na inibição in vitro da formação do tubo endotelial. In vivo a FS foi capaz de inibir o crescimento dos tumores sólidos do melanoma e do carcinoma renal murino de forma superior aos quimioterápicos Dacarbazina (DITC) e ao Sunitinib. No modelo de metástase pulmonar utilizando as células RENCA, a FS reduziu o número de nódulos metastáticos pulmonares e aumentou a taxa de sobrevida dos animais. Os efeitos terapêuticos da FS também foram avaliados no modelo de leucemia promielocítica aguda (LPA) transplantada em camundongos NOD/Scid. O tratamento com a FS reduziu o número de blastos periféricos e infiltrados na medula óssea e nos parênquimas, esplênico e hepático. De forma superior a Daunorrubicina (DA) e ao Ácido all-trans retinóico (ATRA), a FS induziu apoptose nos clones malignos que expressão CD34+, bem como nas células CD117+/Gr-1+. Este conjunto de resultados mostra que a FS é um composto promissor na terapêutica contra neoplasias / In this study, we evaluated the antitumor effects of synthetic phosphoethanolamine (FS) in an experimental tumor model and the signaling pathways involved in this activity. In vitro, FS was cytotoxic to tumor cell lines of human melanoma, SK- MEL-28, renal carcinoma murine, Renca, and for non-small cell lung cancer, NSCLC. Ultrastructural changes such as chromatin condensation, blubes formation on membranes and electrodense mitochondria were accompanied by a reduction of the mitochondrial electric potential. Increased activation of caspase-3, 8 and Bax protein expression, in addition to a reduction of CDK9 and CDK4/6 levels, was also observed. The reduction of migration and proliferation of endothelial cells, HUVEC, induced by FS was associated with the modulation of VEGF-A-expression, resulting in the in vitro inhibition of tubulogenesis. In vivo, FS was able to inhibit the growth of solid tumors of melanoma and renal carcinoma more potently than Dacarbazine (DITC) and Sunitinib. In the lung metastasis model, using RENCA cells, FS reduced the number of metastatic lung nodules and increased the survival rate of the animals. The therapeutic effects of FS were also evaluated in the model of acute promyelocytic leukemia transplanted in mice NOD/Scid. The treatment with FS reduced the number of peripheral blasts and infiltrates in the blood marrow, splenic and hepatic parenchyma. Fs was more potent than Daunorrubicine (DA) and all-trans retinoic acid (ATRA) in the induction of apoptosis in the malignant clones expressing CD34+ as well as CD117+/Gr-1+ cells. Taken together, theses results show that FS is a promising compound for the therapy against tumors

Background: The 5 subunits of native pentameric C-reactive protein (CRP) are dissociated to generate the monomeric form of CRP (mCRP) in some in vitro conditions, both physiological and non-physiological, and also in vivo. Many bioactivities of mCRP generated by urea-treatment of CRP and of mCRP generated by mutating the primary structure of CRP have been reported. The bioactivities of mCRP generated by spontaneous dissociation of CRP are largely unexplored. Methods: We purified mCRP generated by spontaneous dissociation of CRP and investigated the binding of mCRP to enzymatically-modified low-density lipoprotein (E-LDL). Results: mCRP was approximately 60 times more potent than CRP in binding to E-LDL. In the presence of the small-molecule compound phosphoethanolamine (PEt), at 37 °C, the binding of mCRP to E-LDL was enhanced <2-fold, while the binding of CRP to E-LDL was enhanced >10-fold. In contrast, PEt inhibited the binding of both CRP and mCRP to pneumococcal C-polysaccharide, another phosphocholine-containing ligand to which CRP and mCRP were found to bind. We have not investigated yet whether PEt alters the structure of CRP at 37 °C. Conclusions: Combined data suggest that the targeting of CRP with the aim to monomerize CRP in vivo may be an effective approach to capture modified forms of LDL.

The connection between C-reactive protein (CRP) and atherosclerosis lies on three grounds. First, the concentration of CRP in the serum, which is measured by using highly sensitive (a.k.a. 'hs') techniques, correlates with the occurrence of cardiovascular disease. Second, although CRP binds only to Fcγ receptor-bearing cells and, in general, to apoptotic and damaged cells, almost every type of cultured mammalian cells has been shown to respond to CRP treatment. Many of these responses indicate proatherogenic functions of CRP but are being reinvestigated using CRP preparations that are free of endotoxins, sodium azide, and biologically active peptides derived from the protein itself. Third, CRP binds to modified forms of low-density lipoprotein (LDL), and, when aggregated, CRP can bind to native LDL as well. Accordingly, CRP is seen with LDL and damaged cells at the atherosclerotic lesions and myocardial infarcts. In experimental rats, human CRP was found to increase the infarct size, an effect that could be abrogated by blocking CRP-mediated complement activation. In the Apob 100/100 Ldlr -/- murine model of atherosclerosis, human CRP was shown to be atheroprotective, and the importance of CRP-LDL interactions in this protection was noted. Despite all this, at the end, the question whether CRP can protect humans from developing atherosclerosis remains unanswered.

Fosfoetanolamina sintética (Pho-s) é um monoéster análogo à fosfoetanolamina da membrana celular fosforilada artificialmente, com propriedades antiinflamatórias e apoptóticas para vários tipos de células tumorais humanas e murinas. Neste projeto foram avaliados os efeitos antitumorais in vitro da Pho-s e da formulação lipossomal DODAC/Pho-s na linhagem tumoral de leucemia mielóide crônica humana (K-562), em comparação ao modelo resistente a múltiplas drogas K-562 Lucena (MDR+). Os efeitos de citotoxicidade da Pho-s na linhagem tumoral K-562 e K-562 Lucena (MDR+) foram avaliados pela viabilidade celular utilizando o teste da Sulforodamina B, e os valores da IC50% obtidos foram de 43.1 mM e 145.9 mM, respectivamente após 24 horas de tratamento. O tratamento com o carreador DODAC vazio nas células K-562 e K-562 Lucena (MDR+) a IC50% foi de 0,0003mM e 0,008mM respectivamente, e com o tratamento com a formulação lipossomal DODAC/Pho-s a IC50% obtida respectivamente de, 0,56 mM e 0,31 mM. A viabilidade celular foi determinada a exclusão pelo azul de tripan 0,2%, em sistema automatizado Vi-Cell e foram significativas as diminuições da viabilidade celular em comparação ao grupo controle não tratado nas diversas concentrações e em diferentes períodos de tempo de tratamento. As alterações nas distribuições nas populações celulares nas fases do ciclo celular determinadas por citometria de fluxo mostraram aumento do DNA fragmentado (Sub/G1) em 12 e 24 horas de tratamento. Atividade apoptótica das células tumorais pela expressão da Anexina V/PI, no estágio de apoptose inicial, apoptose tardia e necrose foram quantificadas em citometria de fluxo, o tratamento com Pho-s, quando comparado ao grupo controle K-562 (40 e 80 mM) e K-562 Lucena (MDR+) (146 e 292 mM) ocorreu aumento significativo do número de células apoptóticas e em menor percentual o número de células necróticas. O tratamento com a Pho-s em célula leucêmica K-562 e K-562 Lucena (MDR+) tratadas, respectivamente com 40 e 80 mM e 146 e 292 mM mostraram que independente da expressão do fenótipo de resistência há uma redução significativa no potencial elétrico mitocondrial, analisado pelo o ensaio da rodamina-123. Os marcadores de controle e progressão do ciclo celular e da apoptose, mostraram efeitos moduladores da Pho-s dependentes da p53 na expressão da moléculas pró-apoptóticas. Esse conjunto de informações demonstrou os efeitos apoptóticos da Pho-s e da formulação lipossomal nas células tumorais independentemente do perfil molecular de resistência (MDR+), o que possibilita dizer que esse composto possui significativo potencial terapêutico nesse grupo de leucemias / Synthetic phosphoethanolamine (Pho-s) is a monoester analogous to the phosphoethanolamine which composes the membrane of an artificially phosphorylated cell, with anti-inflammatory and apoptotic properties for various types of human and murine tumor cells. In this project, we evaluated in vitro antitumor effects of Pho-s and the DODAC/Pho-s liposomal formulation in the human chronic myeloid leukemia (K-562) tumor line in comparison with the K-562 Lucena (MDR+). The effects of cytotoxicity of Pho-s on K-562 and K-562 Lucena (MDR +) tumor cells lines were evaluated by cell viability using the Sulforhodamine B test, and the IC50% values obtained were 43.1 mM and 145.9 mM after 24 hours of treatment, respectively. Treatment with the empty DODAC carrier on the K-562 and K-562 Lucena (MDR+) at IC50% cells was 0.0003 mM and 0.008 mM, and the treatment with the DODAC/Pho-s liposomal formulation obtained results of 0.56 mM and 0.31 mM, respectively. Cell viability was determined by 0.2% trypan blue exclusion in automated Vi-Cell system and the decreases in cell viability were significant in comparison to the untreated control group at various concentrations and different treatment time periods. Alterations in the distributions of cell populations in the cell cycle phases determined by flow cytometry showed increment of fragmented DNA (Sub/G1) in 12 and 24 hours of treatment. Apoptotic activity of tumor cells by the expression of Annexin V/PI, in the early apoptosis, late apoptosis phase and necrosis stage were quantified in flow cytometry, the treatment with Pho-s, when compared to the control group K-562 (40 and 80 mM) and K-562 Lucena (MDR +) (146 and 292 mM) demonstrated that there was a significant increase in the number of apoptotic cells and, in a lower percentage, the number of necrotic cells. Treatments with Pho-s in leukemic cell K-56 with 40 and 80 mM and in K-562 Lucena (MDR+) with 146 and 292 mM showed that independent of the expression of the resistance phenotype there is a significant reduction in the electrical potential of the mitochondrial membrane, analyzed with the rhodamine-123 assay. Control and progression markers of cell cycle and apoptosis showed p53-dependent modulating effects on the expression of pro-apoptotic molecules. This set of information demonstrated the apoptotic effects of Pho-s and liposomal formulation on tumor cells independently of the molecular resistance profile (MDR+), which makes it possible to say that this compound has significant therapeutic potential in this group of leukemias

O câncer de pulmão é um dos mais incidentes e letais, e, assim, a busca de novos fármacos é necessária. Atualmente o desenvolvimento de fármacos conta com abordagens computacionais que otimizam este processo. Dado que a fosfatidiletanolamina desempenha importantes papeis fisiológicos e uma das enzimas envolvidas na sua síntese, a CTP:fosfoetanolamina-citidilil-transferase (Pcyt2) é frequentemente superexpressa em células de câncer de pulmão, no presente trabalho, foram avaliados o potencial terapêutico de CHY-1, um análogo da miltefosina desenvolvido como inibidor da enzima Pcyt2, e os mecanismos inerentes à sua atividade antitumoral. O CHY-1 apresentou citotoxicidade superior ao seu protótipo e a outro inibidor da enzima Pcyt2, a meclizina. Além disso, as células malignas foram mais sensíveis ao CHY-1 do que as células não-tumorigênicas. Em conclusão, o presente trabalho evidencia o potencial do CHY-1 como um inibidor da enzima Pcyt2 e candidato a fármaco com atividade preferencial para câncer de pulmão. / Lung cancer is one of the most incident and lethal cancers, thus, the pursuit for new drugs is necessary. Nowadays, new drugs development has computational tools that improves this process. Once that phosphatidylethanolamine plays several important physiological roles and one of the enzymes of its production pathway, CTP:phosphoethanolamine cytidylyltransferase (Pcyt2), is usually overexpressed in lung cancer cells, therefore, this study aimed was to evaluate the antitumor effects of CHY-1, a miltefosine analogue developed as an inhibitor of Pcyt2 enzyme, and to investigate the mechanisms related to its antitumor action. CHY-1 was more cytotoxicity than its prototype, miltefosine, and was more cytotoxic than another inhibitor Pcyt2 enzyme, meclizine. Morevover, malignant cells were more sensitive to CHY-1 effects than non-tumorigenic cells. In conclusion, this work presents CHY-1 as an inhibitor of Pcyt2 enzyme and new candidate a drug with preferential activity on NSCLC cells.

A Fosfoetanolamina sintética (Pho-s) é uma molécula análoga aos fosfolipídios de membrana celular com propriedades antitumorais, antiinflamatórias e antiproliferativas. Nosso grupo de pesquisa desenvolveu diversos estudos in vitro e in vivo com a Pho-s mostrando resultados satisfatórios quanto à sua eficácia antitumoral. Neste estudo foram avaliados os efeitos antitumorais in vitro da Pho-s e da formulação lipossomal DODAC/Pho-s em linhagem de adenocarcinoma de mama humana (MCF7). Os efeitos da citotoxicidade da Pho-s na linhagem tumoral MCF7 foi avaliado pela determinação da viabilidade celular pelo teste colorimétrico MTT e os valores obtidos da IC50% foram de 37,2; 25,8; 1,8 mM nos períodos de 24, 48 e 72 horas, respectivamente. Com o tratamento de DODAC vazio nas células MCF7 a IC50% foi de 0,3 mM e com o tratamento de DODAC/Pho-s a IC50% de 1,8 mM, após 24 horas de tratamento. A produção de radicais livres lipoperoxidados foi avaliada pela formação do TBARS em células MCF7, tratadas por 24, 48 e 72 horas com Pho-s, não mostrando diferença significativa nos valores de lipoperoxidação. As alterações nas distribuições das populações celulares nas fases do ciclo celular avaliadas por citometria de fluxo mostraram um aumento do DNA fragmentado após 48 horas e parada na fase G2/M após 24 horas. As alterações nos arranjos celulares foram avaliadas por meio da marcação com os fluorocromos acridine-orange e rodamina 123 por microscopia confocal a laser, no qual foi observada a mudança na morfologia, fragmentação de membranas e perdas da projeção de prolongamentos citoplasmáticos. A indução de células em senescência foi avaliada pela atividade enzimática com a enzima beta-galactosidase, mostrando uma diminuição das células senescentes nas maiores concentrações de tratamento com a Pho-s e com o DODAC/Pho-s. Diversos marcadores de controle e progressão do ciclo celular, stress, angiogênese e receptores hormonais e o potencial mitocondrial foram avaliados por citometria de fluxo. A atividade apoptótica das células tumorais de mama foi avaliada pela Anexina V/PI, mostrando um aumento, principalmente, da apoptose tardia e seus ensaios de proliferação celular pelo teste com o CFSE-DA resultou na diminuição significativa da capacidade de proliferação celular. O tratamento das células de adenocarcinoma de mama humana MCF7 com a Pho-s mostrou ser um composto de natureza fosfolipídica com potencial promissor antitumoral / Synthetic Phosphoethanolamine (Pho-s) is a molecule analogous to cell membrane phospholipids with antitumor, anti-inflammatory and antiproliferative effects. Our research group has developed several in vitro and in vivo studies with Pho-s showing satisfactory results regarding its antitumor efficacy. In this project we evaluated the in vitro antitumor effects of Pho-s and the liposomal formulation DODAC/Pho-s in human breast adenocarcinoma line (MCF7). The effects of the Pho-s cytotoxicity on the MCF7 tumor cell line were evaluated by determining the cell viability by the MTT colorimetric test and the concentration of IC50% were 37.2; 25.8; 1.8 mM in the 24, 48 and 72 hour periods, respectively. With DODAC treatment in MCF7 cells the IC50% was 0.3 mM and the treatment of DODAC/Pho-s at IC50% of 1.8 mM after 24 hours of treatment. The production of lipoperoxides radicals was evaluated by the formation of TBARS in MCF7 cells, treated for 24, 48 and 72 hours with Pho-s, showing no significant difference in lipoperoxidation values. Changes in the cell population distributions in the cell cycle phases evaluated by flow cytometry showed an increase of the fragmented DNA after 48 hours and stop at the G2/M phase after 24 hours. Alterations in the cellular arrangements were evaluated by means of the labeling with the fluorochromes acridine-orange and rhodamine 123 using laser confocal microscopy, in which the change in morphology, membrane fragmentation and loss of the projection of cytoplasmic prolongations were observed. Senescent cell induction was evaluated by enzymatic activity with the ?-galactosidase enzyme, showing a decrease in senescent cells at the highest concentrations of treatment with Pho-s and DODAC/Pho-s. Several control markers and cell cycle progression, stress, angiogenesis and hormone receptors and mitochondrial potential were evaluated by flow cytometry. The apoptotic activity of breast tumor cells was evaluated by Annexin V/PI, showing an increase mainly of late apoptosis and cell proliferation assays by the CFSE-DA with the Pho-s by flow cytometry, resulting in significant decrease of cell proliferation. Treatment of MCF 7 human breast adenocarcinoma cells with Pho-s has been shown to be a phospholipid-type compound with promising antitumor potential