M. Costas - Academia.edu (original) (raw)
Papers by M. Costas
Microbiology, 1989
Twenty-five strains classified as Mycoplasma mycoides subsp. mycoides LC or subsp. capri have bee... more Twenty-five strains classified as Mycoplasma mycoides subsp. mycoides LC or subsp. capri have been compared by one-dimensional SDS-PAGE of their cellular proteins. A computerized numerical analysis revealed that the protein patterns of all but two aberrant strains formed one large phenon that separated clearly from representatives of the four other members of the 'M. mycoides cluster' at a similarity level (S) of 66% and which remained undivided at up to 78% S. At higher similarity levels, these strains fell heterogeneously into mixed sub-phenons containing strains of both subspecies. Serological comparisons by immunofluorescence largely confirmed the subspecies designations of the test strains, but also showed that some were serologically intermediate between subsp. mycoides and subsp. Capri, being cross-reactive with both. These results confirm and enlarge upon those of our earlier studies indicating the proteinpattern inseparability of subsp. capri and subsp. mycoides LC strains and their distinctiveness from the classical M. mycoides subsp. mycoides SC strains and other members of the 'M. mycoides cluster'. As also recognized by other workers, subsp. mycoides LC and subsp. capri strains appear to comprise one large group, wherein those most readily identifiable as either type lie at either end of a serological spectrum that also contains serologically cross-reactive strains. Our observations therefore suggest the lines along which the three groups classified at present within the species M. mycoides (SC and LC strains of subsp. mycoides; subsp. capri) might eventually be reclassified, subject to direct genomic comparisons.
Annals of the New York Academy of Sciences, 1998
Oncogene, 2005
Breast tumors are usually classified according to their response to estrogens as hormone-dependen... more Breast tumors are usually classified according to their response to estrogens as hormone-dependent or-independent. In this work, we investigated the role of the proinflammatory cytokine TNF-a on the estrogen-receptor-positive T47D breast ductal tumor cells. We have found that TNF-a exerts a mitogenic effect, inducing cyclin D1 expression and activation of the transcription factor NF-jB. Importantly, activation of NF-jB was required for estrogen-induced proliferation and cyclin D1 expression. TNF-a enhanced the estrogen response by increasing the levels and availability of NF-jB. Chromatin immunoprecipitation analysis suggested that the action of estrogens is mediated by a protein complex that contains the activated estrogen receptor, the nuclear receptor coactivator RAC3 and a member of the NF-jB family. Finally, our results demonstrate that activation of this transcription factor could be one of the key signals for estrogen-mediated response.
Cancer Research, 2020
Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and the Cancer Stem Cells (... more Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and the Cancer Stem Cells (CSC) are the responsible of CRC persistence. Aloysia polystachya (AP) is an aromatic native plant of Verbenaceae family which is widely distributed and consumed in infusions in subtropical regions of South America. Its effects include diuretic, sedative, antispasmodic activities. We have previously demonstrated that AP extract has a cytotoxic effect in several human tumor cell lines, including apoptosis. The aim of this work was to investigate the cytotoxic effects of AP in vitro and in vivo in a CRC model. Therefore, CRC cell lines CT26 (murine) and HCT116 (human), were stimulated with AP extract or vehicle, with or without 5-fluorouracyle (5-FURA) and the survival and CSC properties were determined. The survival was measured after crystal violet staining at 570nm and CSC phenotype was determined by measuring the plurytpotency markers (CD133, OCT4 and Nanog by PCR and IFI), colony forma...
The Journal of Immunology, 2004
MHC class I-related chain A gene (MICA) is a stress-regulated, HLA-related molecule which exhibit... more MHC class I-related chain A gene (MICA) is a stress-regulated, HLA-related molecule which exhibits a restricted pattern of expression. MICA protein is up-regulated on different tumor cells, and is recognized by the lectin-like NKG2D molecule expressed by cytotoxic γδ T lymphocytes, CD8+ αβ T lymphocytes, and NK cells. Although MICA is not expressed on resting lymphocytes, we demonstrated that it is induced on activated T cells. Because NF-κB is actively involved in T cell activation, and is constitutively activated in many tumors, here we investigated whether NF-κB may modulate MICA expression. Treatment with the NF-κB inhibitor sulfasalazine (Sz) resulted in a dose-dependent inhibition of MICA expression in anti-CD3- and anti-CD28/PMA-activated T lymphocytes, as assessed by Western blot and RT-PCR analysis. Moreover, Sz also down-regulated MICA expression on epithelial tumor HeLa cells. MICA expression was accompanied by a Sz-sensitive IκBα degradation. EMSA with nuclear extracts f...
The Journal of Immunology, 2006
We have previously shown that bacterial DNA activates human neutrophils in a CpG-independent mann... more We have previously shown that bacterial DNA activates human neutrophils in a CpG-independent manner. In this study, we have characterized the signaling pathways involved in the activation mechanism. We found that p38 MAPK, ERK1/2, and JNK pathways, as well as the PI3K/Akt pathway, are activated by bacterial DNA. We also determined that bacterial DNA induces NF-κB and AP-1 activation. When analyzing the role of these pathways on neutrophil functions, we observed that up-regulation of CD11b triggered by bacterial DNA was decreased by pharmacological inhibitors of the p38 MAPK, ERK1/2, and JNK, whereas stimulation of IL-8 release was dependent on p38, ERK1/2, and NF-κB. Moreover, we found that IL-8 production was markedly enhanced by inhibition of JNK, suggesting that this pathway negatively modulates NF-κB-dependent transcription. We also observed that bacterial DNA stimulated IL-1R-associated kinase-1 kinase activity and its partial degradation. Finally, we determined that bacterial ...
Journal of Clinical Investigation, 1996
Cytokine-induced glucocorticoid secretion and glucocorticoid inhibition of cytokine synthesis and... more Cytokine-induced glucocorticoid secretion and glucocorticoid inhibition of cytokine synthesis and pleiotropic actions act as important safeguards in preventing cytokine overreaction. We found that TNF-␣ increased glucocorticoid-induced transcriptional activity of the glucocorticoid receptor (GR) via the glucocorticoid response elements (GRE) in L-929 mouse fibroblasts transfected with a glucocorticoid-inducible reporter plasmid. In addition, TNF-␣ also enhanced GR number. The TNF-␣ effect on transcriptional activity was absent in other cell lines that express TNF-␣ receptors but not GRs, and became manifest when a GR expression vector was cotransfected, indicating that TNF-␣ , independent of any effect it may have on GR number, has a stimulatory effect on the glucocorticoid-induced transcriptional activity of the GR. Moreover, TNF-␣ increased GR binding to GRE. As a functional biological correlate of this mechanism, priming of L-929 cells with a low (noncytotoxic) dose of TNF-␣ significantly increased the sensitivity to glucocorticoid inhibition of TNF-␣-induced cytotoxicity/apoptosis. TNF-␣ and IL-1  had the same stimulatory action on glucocorticoid-induced transcriptional activity of the GR via the GRE, in different types of cytokine/glucocorticoid target cells (glioma, pituitary, epithelioid). The phenomenon may therefore reflect a general molecular mechanism whereby cytokines modulate the transcriptional activity of the GR, thus potentiating the counterregulation by glucocorticoids at the level of their target cells.
The Journal of Immunology, 2004
A gene (MICA) is a stress-regulated, HLA-related molecule which exhibits a restricted pattern of ... more A gene (MICA) is a stress-regulated, HLA-related molecule which exhibits a restricted pattern of expression. MICA protein is up-regulated on different tumor cells, and is recognized by the lectin-like NKG2D molecule expressed by cytotoxic ␥␦ T lymphocytes, CD8 ؉ ␣ T lymphocytes, and NK cells. Although MICA is not expressed on resting lymphocytes, we demonstrated that it is induced on activated T cells. Because NF-B is actively involved in T cell activation, and is constitutively activated in many tumors, here we investigated whether NF-B may modulate MICA expression. Treatment with the NF-B inhibitor sulfasalazine (Sz) resulted in a dose-dependent inhibition of MICA expression in anti-CD3-and anti-CD28/PMA-activated T lymphocytes, as assessed by Western blot and RT-PCR analysis. Moreover, Sz also down-regulated MICA expression on epithelial tumor HeLa cells. MICA expression was accompanied by a Sz-sensitive IB␣ degradation. EMSA with nuclear extracts from anti-CD3-and anti-CD28/PMA-stimulated T lymphocytes demonstrated the binding of a potential NF-B family transcription factor to a MICA gene intron 1-derived oligonucleotide that contains a putative B binding site. Supershift assays demonstrated the presence of p65(RelA)/p50 heterodimers and p50/p50 homodimers in the NF-B complexes bound to the B-MICA oligonucleotide. Transient transfection of HeLa cells with p65(RelA) up-regulated MICA expression, as assessed by Western blot and flow cytometry analysis. Hence, we conclude that NF-B regulates MICA expression on activated T lymphocytes and HeLa tumor cells, by binding to a specific sequence in the long intron 1 of the MICA gene. This constitutes the first description of a transcription factor that regulates MICA gene expression.
Oncogene, 2008
The p160 nuclear receptor co-activators represent a family of molecules, which are recruited by s... more The p160 nuclear receptor co-activators represent a family of molecules, which are recruited by steroid nuclear receptors as well as other transcription factors that are overexpressed in several tumors. We investigated the role of one member of this family on the sensitivity of cells to apoptosis. We observed that overexpression of the RAC3 (receptor-associated co-activator-3) p160 co-activator inhibits hydrogen peroxide-induced cell death in human embryonic kidney 293 (HEK293) cells. The mechanism involves the activation of anti-apoptotic pathways mediated through enhanced nuclear factor kappa B (NF-jB) activity, inhibition of caspase-9 activation, diminished apoptotic-inducing factor (AIF) nuclear localization and a change in the activation pattern of several kinases, including an increase in both AKT and p38 kinase activities, and inhibition of ERK2. Moreover, RAC3 has been found associated with a protein complex containing AIF, Hsp90 and dynein, suggesting a role for the coactivator in the cytoplasmatic nuclear transport of these proteins associated with cytoskeleton. These results demonstrate that there are several molecular pathways that could be affected by their overexpression, including those not restricted to steroid regulation or the nuclear action of co-activators, which results in diminished sensitivity to apoptosis. Furthermore, this could represent one mechanism by which co-activators contribute to tumor development.
Microbiology, 1989
Twenty-five strains classified as Mycoplasma mycoides subsp. mycoides LC or subsp. capri have bee... more Twenty-five strains classified as Mycoplasma mycoides subsp. mycoides LC or subsp. capri have been compared by one-dimensional SDS-PAGE of their cellular proteins. A computerized numerical analysis revealed that the protein patterns of all but two aberrant strains formed one large phenon that separated clearly from representatives of the four other members of the 'M. mycoides cluster' at a similarity level (S) of 66% and which remained undivided at up to 78% S. At higher similarity levels, these strains fell heterogeneously into mixed sub-phenons containing strains of both subspecies. Serological comparisons by immunofluorescence largely confirmed the subspecies designations of the test strains, but also showed that some were serologically intermediate between subsp. mycoides and subsp. Capri, being cross-reactive with both. These results confirm and enlarge upon those of our earlier studies indicating the proteinpattern inseparability of subsp. capri and subsp. mycoides LC strains and their distinctiveness from the classical M. mycoides subsp. mycoides SC strains and other members of the 'M. mycoides cluster'. As also recognized by other workers, subsp. mycoides LC and subsp. capri strains appear to comprise one large group, wherein those most readily identifiable as either type lie at either end of a serological spectrum that also contains serologically cross-reactive strains. Our observations therefore suggest the lines along which the three groups classified at present within the species M. mycoides (SC and LC strains of subsp. mycoides; subsp. capri) might eventually be reclassified, subject to direct genomic comparisons.
Annals of the New York Academy of Sciences, 1998
Oncogene, 2005
Breast tumors are usually classified according to their response to estrogens as hormone-dependen... more Breast tumors are usually classified according to their response to estrogens as hormone-dependent or-independent. In this work, we investigated the role of the proinflammatory cytokine TNF-a on the estrogen-receptor-positive T47D breast ductal tumor cells. We have found that TNF-a exerts a mitogenic effect, inducing cyclin D1 expression and activation of the transcription factor NF-jB. Importantly, activation of NF-jB was required for estrogen-induced proliferation and cyclin D1 expression. TNF-a enhanced the estrogen response by increasing the levels and availability of NF-jB. Chromatin immunoprecipitation analysis suggested that the action of estrogens is mediated by a protein complex that contains the activated estrogen receptor, the nuclear receptor coactivator RAC3 and a member of the NF-jB family. Finally, our results demonstrate that activation of this transcription factor could be one of the key signals for estrogen-mediated response.
Cancer Research, 2020
Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and the Cancer Stem Cells (... more Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and the Cancer Stem Cells (CSC) are the responsible of CRC persistence. Aloysia polystachya (AP) is an aromatic native plant of Verbenaceae family which is widely distributed and consumed in infusions in subtropical regions of South America. Its effects include diuretic, sedative, antispasmodic activities. We have previously demonstrated that AP extract has a cytotoxic effect in several human tumor cell lines, including apoptosis. The aim of this work was to investigate the cytotoxic effects of AP in vitro and in vivo in a CRC model. Therefore, CRC cell lines CT26 (murine) and HCT116 (human), were stimulated with AP extract or vehicle, with or without 5-fluorouracyle (5-FURA) and the survival and CSC properties were determined. The survival was measured after crystal violet staining at 570nm and CSC phenotype was determined by measuring the plurytpotency markers (CD133, OCT4 and Nanog by PCR and IFI), colony forma...
The Journal of Immunology, 2004
MHC class I-related chain A gene (MICA) is a stress-regulated, HLA-related molecule which exhibit... more MHC class I-related chain A gene (MICA) is a stress-regulated, HLA-related molecule which exhibits a restricted pattern of expression. MICA protein is up-regulated on different tumor cells, and is recognized by the lectin-like NKG2D molecule expressed by cytotoxic γδ T lymphocytes, CD8+ αβ T lymphocytes, and NK cells. Although MICA is not expressed on resting lymphocytes, we demonstrated that it is induced on activated T cells. Because NF-κB is actively involved in T cell activation, and is constitutively activated in many tumors, here we investigated whether NF-κB may modulate MICA expression. Treatment with the NF-κB inhibitor sulfasalazine (Sz) resulted in a dose-dependent inhibition of MICA expression in anti-CD3- and anti-CD28/PMA-activated T lymphocytes, as assessed by Western blot and RT-PCR analysis. Moreover, Sz also down-regulated MICA expression on epithelial tumor HeLa cells. MICA expression was accompanied by a Sz-sensitive IκBα degradation. EMSA with nuclear extracts f...
The Journal of Immunology, 2006
We have previously shown that bacterial DNA activates human neutrophils in a CpG-independent mann... more We have previously shown that bacterial DNA activates human neutrophils in a CpG-independent manner. In this study, we have characterized the signaling pathways involved in the activation mechanism. We found that p38 MAPK, ERK1/2, and JNK pathways, as well as the PI3K/Akt pathway, are activated by bacterial DNA. We also determined that bacterial DNA induces NF-κB and AP-1 activation. When analyzing the role of these pathways on neutrophil functions, we observed that up-regulation of CD11b triggered by bacterial DNA was decreased by pharmacological inhibitors of the p38 MAPK, ERK1/2, and JNK, whereas stimulation of IL-8 release was dependent on p38, ERK1/2, and NF-κB. Moreover, we found that IL-8 production was markedly enhanced by inhibition of JNK, suggesting that this pathway negatively modulates NF-κB-dependent transcription. We also observed that bacterial DNA stimulated IL-1R-associated kinase-1 kinase activity and its partial degradation. Finally, we determined that bacterial ...
Journal of Clinical Investigation, 1996
Cytokine-induced glucocorticoid secretion and glucocorticoid inhibition of cytokine synthesis and... more Cytokine-induced glucocorticoid secretion and glucocorticoid inhibition of cytokine synthesis and pleiotropic actions act as important safeguards in preventing cytokine overreaction. We found that TNF-␣ increased glucocorticoid-induced transcriptional activity of the glucocorticoid receptor (GR) via the glucocorticoid response elements (GRE) in L-929 mouse fibroblasts transfected with a glucocorticoid-inducible reporter plasmid. In addition, TNF-␣ also enhanced GR number. The TNF-␣ effect on transcriptional activity was absent in other cell lines that express TNF-␣ receptors but not GRs, and became manifest when a GR expression vector was cotransfected, indicating that TNF-␣ , independent of any effect it may have on GR number, has a stimulatory effect on the glucocorticoid-induced transcriptional activity of the GR. Moreover, TNF-␣ increased GR binding to GRE. As a functional biological correlate of this mechanism, priming of L-929 cells with a low (noncytotoxic) dose of TNF-␣ significantly increased the sensitivity to glucocorticoid inhibition of TNF-␣-induced cytotoxicity/apoptosis. TNF-␣ and IL-1  had the same stimulatory action on glucocorticoid-induced transcriptional activity of the GR via the GRE, in different types of cytokine/glucocorticoid target cells (glioma, pituitary, epithelioid). The phenomenon may therefore reflect a general molecular mechanism whereby cytokines modulate the transcriptional activity of the GR, thus potentiating the counterregulation by glucocorticoids at the level of their target cells.
The Journal of Immunology, 2004
A gene (MICA) is a stress-regulated, HLA-related molecule which exhibits a restricted pattern of ... more A gene (MICA) is a stress-regulated, HLA-related molecule which exhibits a restricted pattern of expression. MICA protein is up-regulated on different tumor cells, and is recognized by the lectin-like NKG2D molecule expressed by cytotoxic ␥␦ T lymphocytes, CD8 ؉ ␣ T lymphocytes, and NK cells. Although MICA is not expressed on resting lymphocytes, we demonstrated that it is induced on activated T cells. Because NF-B is actively involved in T cell activation, and is constitutively activated in many tumors, here we investigated whether NF-B may modulate MICA expression. Treatment with the NF-B inhibitor sulfasalazine (Sz) resulted in a dose-dependent inhibition of MICA expression in anti-CD3-and anti-CD28/PMA-activated T lymphocytes, as assessed by Western blot and RT-PCR analysis. Moreover, Sz also down-regulated MICA expression on epithelial tumor HeLa cells. MICA expression was accompanied by a Sz-sensitive IB␣ degradation. EMSA with nuclear extracts from anti-CD3-and anti-CD28/PMA-stimulated T lymphocytes demonstrated the binding of a potential NF-B family transcription factor to a MICA gene intron 1-derived oligonucleotide that contains a putative B binding site. Supershift assays demonstrated the presence of p65(RelA)/p50 heterodimers and p50/p50 homodimers in the NF-B complexes bound to the B-MICA oligonucleotide. Transient transfection of HeLa cells with p65(RelA) up-regulated MICA expression, as assessed by Western blot and flow cytometry analysis. Hence, we conclude that NF-B regulates MICA expression on activated T lymphocytes and HeLa tumor cells, by binding to a specific sequence in the long intron 1 of the MICA gene. This constitutes the first description of a transcription factor that regulates MICA gene expression.
Oncogene, 2008
The p160 nuclear receptor co-activators represent a family of molecules, which are recruited by s... more The p160 nuclear receptor co-activators represent a family of molecules, which are recruited by steroid nuclear receptors as well as other transcription factors that are overexpressed in several tumors. We investigated the role of one member of this family on the sensitivity of cells to apoptosis. We observed that overexpression of the RAC3 (receptor-associated co-activator-3) p160 co-activator inhibits hydrogen peroxide-induced cell death in human embryonic kidney 293 (HEK293) cells. The mechanism involves the activation of anti-apoptotic pathways mediated through enhanced nuclear factor kappa B (NF-jB) activity, inhibition of caspase-9 activation, diminished apoptotic-inducing factor (AIF) nuclear localization and a change in the activation pattern of several kinases, including an increase in both AKT and p38 kinase activities, and inhibition of ERK2. Moreover, RAC3 has been found associated with a protein complex containing AIF, Hsp90 and dynein, suggesting a role for the coactivator in the cytoplasmatic nuclear transport of these proteins associated with cytoskeleton. These results demonstrate that there are several molecular pathways that could be affected by their overexpression, including those not restricted to steroid regulation or the nuclear action of co-activators, which results in diminished sensitivity to apoptosis. Furthermore, this could represent one mechanism by which co-activators contribute to tumor development.