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Manuel Santos Rosa - One of the best experts on this subject based on the ideXlab platform.
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cd26 dppiv expression and 8 Azaguanine response in t acute lymphoblastic leukaemia cell lines in culture
Pathophysiology, 2007Co-Authors: Mar Olia Dourado, Ana Bela Sarmento, Sofia Vale Pereira, Vera Alves, Teresa Silva, Anabela Mota Pinto, Manuel Santos RosaAbstract:Dipeptidyl peptidase IV, a cell membrane surface protease also known as CD26 (CD26/DPPIV), is known to play multiple functions in human organism, where it is largely expressed, for instance, in the development of human cancer and metastasis as well as in chemotherapy response. The objective of this work was to study the CD26 membrane expression and DPPIV activity in T-acute leukaemia cell lines (CEM and MOLT3) in culture, in order to observe the modification of its expression under the 8-Azaguanine treatment. Cell line samples were incubated, some without different Azaguanine concentration and others with, ranging from 10 to 100muM. Cell surface CD26 expression has been identified by flow cytometry and DPPIV activity, in cultured medium, was fluorimetrically measured. Results we have observed showed that 8-Azaguanine induced a decrease in cell viability in a dose, time and cell type dependent manner with MOLT3 cells being the most sensitive to 8-Azaguanine citotoxic effects (24h IC50: +/-10muM) when compared with CEM cells (24h IC50: +/-100muM). In the same experimental conditions, MOLT3 cell treated with 8-Azaguanine shows an increase in CD26 expression (MIF) compared with that of CEM cell submitted to the same conditions (65.4+/-1.3 versus 18.7+/-1.7). DPPIV activity in culture medium supernatant of CEM versus MOLT3 controls cells (1.91+/-0.43 versus 2.06+/-0.50) and of CEM versus MOLT3 treated cells (2.10+/-0.16 versus 1.89+/-0.04) did not show a significant difference. These preliminary results suggest that 8-Azaguanine stimulates CD26 expression which may be related to cellular sensitivity to 8-Azaguanine.
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CD26/DPPIV expression and 8-Azaguanine response in T-acute lymphoblastic leukaemia cell lines in culture.
Pathophysiology : the official journal of the International Society for Pathophysiology, 2006Co-Authors: Mar ´ õlia Dourado, Ana Bela Sarmento, Sofia Vale Pereira, Vera Alves, Teresa Silva, Anabela Mota Pinto, Manuel Santos RosaAbstract:Dipeptidyl peptidase IV, a cell membrane surface protease also known as CD26 (CD26/DPPIV), is known to play multiple functions in human organism, where it is largely expressed, for instance, in the development of human cancer and metastasis as well as in chemotherapy response. The objective of this work was to study the CD26 membrane expression and DPPIV activity in T-acute leukaemia cell lines (CEM and MOLT3) in culture, in order to observe the modification of its expression under the 8-Azaguanine treatment. Cell line samples were incubated, some without different Azaguanine concentration and others with, ranging from 10 to 100muM. Cell surface CD26 expression has been identified by flow cytometry and DPPIV activity, in cultured medium, was fluorimetrically measured. Results we have observed showed that 8-Azaguanine induced a decrease in cell viability in a dose, time and cell type dependent manner with MOLT3 cells being the most sensitive to 8-Azaguanine citotoxic effects (24h IC50: +/-10muM) when compared with CEM cells (24h IC50: +/-100muM). In the same experimental conditions, MOLT3 cell treated with 8-Azaguanine shows an increase in CD26 expression (MIF) compared with that of CEM cell submitted to the same conditions (65.4+/-1.3 versus 18.7+/-1.7). DPPIV activity in culture medium supernatant of CEM versus MOLT3 controls cells (1.91+/-0.43 versus 2.06+/-0.50) and of CEM versus MOLT3 treated cells (2.10+/-0.16 versus 1.89+/-0.04) did not show a significant difference. These preliminary results suggest that 8-Azaguanine stimulates CD26 expression which may be related to cellular sensitivity to 8-Azaguanine.
Frank Seela - One of the best experts on this subject based on the ideXlab platform.
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guanine and 8 Azaguanine in anomeric dna hybrid base pairs stability fluorescence sensing and efficient mismatch discrimination with α d nucleosides
Bioconjugate Chemistry, 2018Co-Authors: Jiang Liu, Sachin A. Ingale, Frank SeelaAbstract:The α-anomers of 8-aza-2′-deoxyguanosine (αGd*) and 2′-deoxyguanosine (αGd) were site-specifically incorporated in 12-mer duplexes opposite to the four canonical DNA constituents dA, dG, dT, and dC. Oligodeoxyribonucleotides containing αGd* display significant fluorescence at slightly elevated pH (8.0). Oligodeoxyribonucleotides incorporating β-anomeric 8-aza-2′-deoxyguanosine (Gd*) and canonical dG were studied for comparison. For αGd* synthesis, an efficient purification of anomeric 8-Azaguanine nucleosides was developed on the basis of protected intermediates, and a new αGd* phosphoramidite was prepared. Differences were observed for sugar conformations (N vs S) and pKa values of anomeric nucleosides. Duplex stability and mismatch discrimination were studied employing UV-dependent melting and fluorescence quenching. A gradual fluorescence change takes place in duplex DNA when the α-nucleoside αGd* was positioned opposite to the four canonical β-nucleosides. The strongest fluorescence decrease appeared ...
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Guanine and 8‑Azaguanine in Anomeric DNA Hybrid Base Pairs: Stability, Fluorescence Sensing, and Efficient Mismatch Discrimination with α‑d‑Nucleosides
2018Co-Authors: Jiang Liu, Sachin A. Ingale, Frank SeelaAbstract:The α-anomers of 8-aza-2′-deoxyguanosine (αGd*) and 2′-deoxyguanosine (αGd) were site-specifically incorporated in 12-mer duplexes opposite to the four canonical DNA constituents dA, dG, dT, and dC. Oligodeoxyribonucleotides containing αGd* display significant fluorescence at slightly elevated pH (8.0). Oligodeoxyribonucleotides incorporating β-anomeric 8-aza-2′-deoxyguanosine (Gd*) and canonical dG were studied for comparison. For αGd* synthesis, an efficient purification of anomeric 8-Azaguanine nucleosides was developed on the basis of protected intermediates, and a new αGd* phosphoramidite was prepared. Differences were observed for sugar conformations (N vs S) and pKa values of anomeric nucleosides. Duplex stability and mismatch discrimination were studied employing UV-dependent melting and fluorescence quenching. A gradual fluorescence change takes place in duplex DNA when the α-nucleoside αGd* was positioned opposite to the four canonical β-nucleosides. The strongest fluorescence decrease appeared in duplexes incorporating αGd*-Cd base pair matches. Decreasing fluorescence corresponds to increasing Tm values. For mismatch discrimination, the α-anomers αGd* and αGd are more efficient than the corresponding β-nucleosides. Duplexes with single “purine–purine” αGd*-αGd* or αGd-αGd base pairs are significantly more stable than those displaying β-d configuration. CD spectra indicate that single mutations by α-anomeric nucleosides do not affect the global structure of B-DNA
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8 Azaguanine 2 3 dideoxyribonucleosides glycosylation of the 5 amino 7 methoxy 3h 1 2 3 triazolo 4 5 d pyrimidinyl anion with 2 3 dideoxy d glycero pentofuranosyl chloride
ChemInform, 1994Co-Authors: Frank Seela, Karin MersmannAbstract:The synthesis of the regioisomeric 8-Azaguanine N7-, N8-, and N9-(β-D-2′,3′-dideoxyribonucleosides) (1, 2, and 3, respectively) and of the diamino derivative 13 is described. The anion of 5-amino-7-methoxy-3H-1,2,3-triazolo[4,5-d]pyrimidine (5) was glycosylated with 5-O-[(tert-butyl)dimethylsilyl]-2,3-dideoxy-D-glycero-pentofuranosyl chloride (6; anomeric mixture), yielding the regioisomeric 2′,3′-dideoxyribofuranosides as anomeric mixtures 7a/10a, 8a/11a, and 9a/12a. They were desilylated with Bu4NF in THF affording the 5-amino-7-methoxy-nucleosides 7b–12b. Treatment with aqueous NaOH gave the 8-Azaguanine β-D-2′,3′-dideoxynucleosides 1–3 and their α-D-anomers 14–16. The reaction of 7b with NH3/MeOH yielded the diamino compound 13. The N-glycosylic bond of 8-aza-2′,3′-dideoxyguanosine (1) is four-times more stable against acid than that of 2′,3′-dideoxyguanosine. Compounds 1, 2, and 13 were converted to their 5′-triphosphates 17–19 which showed only modest inhibitory activity against HIV-reverse transcriptase.
Mar Olia Dourado - One of the best experts on this subject based on the ideXlab platform.
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cd26 dppiv expression and 8 Azaguanine response in t acute lymphoblastic leukaemia cell lines in culture
Pathophysiology, 2007Co-Authors: Mar Olia Dourado, Ana Bela Sarmento, Sofia Vale Pereira, Vera Alves, Teresa Silva, Anabela Mota Pinto, Manuel Santos RosaAbstract:Dipeptidyl peptidase IV, a cell membrane surface protease also known as CD26 (CD26/DPPIV), is known to play multiple functions in human organism, where it is largely expressed, for instance, in the development of human cancer and metastasis as well as in chemotherapy response. The objective of this work was to study the CD26 membrane expression and DPPIV activity in T-acute leukaemia cell lines (CEM and MOLT3) in culture, in order to observe the modification of its expression under the 8-Azaguanine treatment. Cell line samples were incubated, some without different Azaguanine concentration and others with, ranging from 10 to 100muM. Cell surface CD26 expression has been identified by flow cytometry and DPPIV activity, in cultured medium, was fluorimetrically measured. Results we have observed showed that 8-Azaguanine induced a decrease in cell viability in a dose, time and cell type dependent manner with MOLT3 cells being the most sensitive to 8-Azaguanine citotoxic effects (24h IC50: +/-10muM) when compared with CEM cells (24h IC50: +/-100muM). In the same experimental conditions, MOLT3 cell treated with 8-Azaguanine shows an increase in CD26 expression (MIF) compared with that of CEM cell submitted to the same conditions (65.4+/-1.3 versus 18.7+/-1.7). DPPIV activity in culture medium supernatant of CEM versus MOLT3 controls cells (1.91+/-0.43 versus 2.06+/-0.50) and of CEM versus MOLT3 treated cells (2.10+/-0.16 versus 1.89+/-0.04) did not show a significant difference. These preliminary results suggest that 8-Azaguanine stimulates CD26 expression which may be related to cellular sensitivity to 8-Azaguanine.
James R Hanson - One of the best experts on this subject based on the ideXlab platform.
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interpretation of results with the 8 Azaguanine resistance system in salmonella typhimurium no evidence for direct acting mutagenesis by 15 oxosteviol a possible metabolite of steviol
Mutagenesis, 1991Co-Authors: Emily Procinska, B A Bridges, James R HansonAbstract:15-Oxosteviol, postulated to be the mutagenic metabolite of steviol, was observed to be non-mutagenic in preliminary experiments using a number of different systems. Repetition of the original experiment in Salmonella TM677 failed to show any significant induction of 8-Azaguanine resistant mutants by 15-oxosteviol even when the number of bacteria tested was greatly increased. Examination of the earlier positive result showed that it could not be justified from the data and revealed a commonly applied way of mishandling data obtained with the TM677 system.
Anabela Mota Pinto - One of the best experts on this subject based on the ideXlab platform.
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cd26 dppiv expression and 8 Azaguanine response in t acute lymphoblastic leukaemia cell lines in culture
Pathophysiology, 2007Co-Authors: Mar Olia Dourado, Ana Bela Sarmento, Sofia Vale Pereira, Vera Alves, Teresa Silva, Anabela Mota Pinto, Manuel Santos RosaAbstract:Dipeptidyl peptidase IV, a cell membrane surface protease also known as CD26 (CD26/DPPIV), is known to play multiple functions in human organism, where it is largely expressed, for instance, in the development of human cancer and metastasis as well as in chemotherapy response. The objective of this work was to study the CD26 membrane expression and DPPIV activity in T-acute leukaemia cell lines (CEM and MOLT3) in culture, in order to observe the modification of its expression under the 8-Azaguanine treatment. Cell line samples were incubated, some without different Azaguanine concentration and others with, ranging from 10 to 100muM. Cell surface CD26 expression has been identified by flow cytometry and DPPIV activity, in cultured medium, was fluorimetrically measured. Results we have observed showed that 8-Azaguanine induced a decrease in cell viability in a dose, time and cell type dependent manner with MOLT3 cells being the most sensitive to 8-Azaguanine citotoxic effects (24h IC50: +/-10muM) when compared with CEM cells (24h IC50: +/-100muM). In the same experimental conditions, MOLT3 cell treated with 8-Azaguanine shows an increase in CD26 expression (MIF) compared with that of CEM cell submitted to the same conditions (65.4+/-1.3 versus 18.7+/-1.7). DPPIV activity in culture medium supernatant of CEM versus MOLT3 controls cells (1.91+/-0.43 versus 2.06+/-0.50) and of CEM versus MOLT3 treated cells (2.10+/-0.16 versus 1.89+/-0.04) did not show a significant difference. These preliminary results suggest that 8-Azaguanine stimulates CD26 expression which may be related to cellular sensitivity to 8-Azaguanine.
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CD26/DPPIV expression and 8-Azaguanine response in T-acute lymphoblastic leukaemia cell lines in culture.
Pathophysiology : the official journal of the International Society for Pathophysiology, 2006Co-Authors: Mar ´ õlia Dourado, Ana Bela Sarmento, Sofia Vale Pereira, Vera Alves, Teresa Silva, Anabela Mota Pinto, Manuel Santos RosaAbstract:Dipeptidyl peptidase IV, a cell membrane surface protease also known as CD26 (CD26/DPPIV), is known to play multiple functions in human organism, where it is largely expressed, for instance, in the development of human cancer and metastasis as well as in chemotherapy response. The objective of this work was to study the CD26 membrane expression and DPPIV activity in T-acute leukaemia cell lines (CEM and MOLT3) in culture, in order to observe the modification of its expression under the 8-Azaguanine treatment. Cell line samples were incubated, some without different Azaguanine concentration and others with, ranging from 10 to 100muM. Cell surface CD26 expression has been identified by flow cytometry and DPPIV activity, in cultured medium, was fluorimetrically measured. Results we have observed showed that 8-Azaguanine induced a decrease in cell viability in a dose, time and cell type dependent manner with MOLT3 cells being the most sensitive to 8-Azaguanine citotoxic effects (24h IC50: +/-10muM) when compared with CEM cells (24h IC50: +/-100muM). In the same experimental conditions, MOLT3 cell treated with 8-Azaguanine shows an increase in CD26 expression (MIF) compared with that of CEM cell submitted to the same conditions (65.4+/-1.3 versus 18.7+/-1.7). DPPIV activity in culture medium supernatant of CEM versus MOLT3 controls cells (1.91+/-0.43 versus 2.06+/-0.50) and of CEM versus MOLT3 treated cells (2.10+/-0.16 versus 1.89+/-0.04) did not show a significant difference. These preliminary results suggest that 8-Azaguanine stimulates CD26 expression which may be related to cellular sensitivity to 8-Azaguanine.
