Adriana Oliva - Academia.edu (original) (raw)
Papers by Adriana Oliva
Oncotarget, 2015
The hope of selectively targeting cancer cells by therapy and eradicating definitively malignanci... more The hope of selectively targeting cancer cells by therapy and eradicating definitively malignancies is based on the identification of pathways or metabolisms that clearly distinguish "normal" from "transformed" phenotypes. Some tyrosine kinase activities, specifically unregulated and potently activated in malignant cells, might represent important targets of therapy. Consequently, tyrosine kinase inhibitors (TKIs) might be thought as the "vanguard" of molecularly targeted therapy for human neoplasias. Imatinib and the successive generations of inhibitors of Bcr-Abl1 kinase, represent the major successful examples of TKI use in cancer treatment. Other tyrosine kinases have been selected as targets of therapy, but the efficacy of their inhibition, although evident, is less definite. Two major negative effects exist in this therapeutic strategy and are linked to the specificity of the drugs and to the role of the targeted kinase in non-malignant cells. In this review, we will discuss the data available on the TKIs effects on the metabolism and functions of mesenchymal stromal cells (MSCs). MSCs are widely distributed in human tissues and play key physiological roles; nevertheless, they might be responsible for important pathologies. At present, bone marrow (BM) MSCs have been studied in greater detail, for both embryological origins and functions. The available data are evocative of an unexpected degree of complexity and heterogeneity of BM-MSCs. It is conceivable that this grade of intricacy occurs also in MSCs of other organs. Therefore, in perspective, the negative effects of TKIs on MSCs might represent a critical problem in long-term cancer therapies based on such inhibitors.
Biochimica et biophysica acta, Jan 3, 2016
Iron overload syndromes include a wide range of diseases frequently associated with increased mor... more Iron overload syndromes include a wide range of diseases frequently associated with increased morbidity and mortality. Several organs are affected in patients with iron overload including liver, heart, joints, endocrine glands, and pancreas. Moreover, severe bone and hemopoietic tissue alterations are observed. Because of the role of bone marrow mesenchymal stromal cells (BM-MSCs) in bone turnover and hematopoiesis, iron effects on primary BM-MSCs cultures were evaluated. Primary human BM-MSCs cultures were prepared and the effects of iron on their proliferation and differentiation were characterized by biochemical analyses and functional approaches. Addition of iron to the culture medium strongly increased BM-MSCs proliferation and induced their accelerated S phase entry. Iron enters BM-MSCs through both transferrin-dependent and transferrin-independent mechanisms, inducing the accumulation of cyclins E and A, the decrease of p27Kip1, and the activation of MAPK pathway. Conversely,...
Oxidative Medicine and Cellular Longevity, 2016
Histone deacetylase inhibitors (HDACIs) represent an intriguing class of pharmacologically active... more Histone deacetylase inhibitors (HDACIs) represent an intriguing class of pharmacologically active compounds. Currently, some HDACIs are FDA approved for cancer therapy and many others are in clinical trials, showing important clinical activities at well tolerated doses. HDACIs also interfere with the aging process and are involved in the control of inflammation and oxidative stress.In vitro, HDACIs induce different cellular responses including growth arrest, differentiation, and apoptosis. Here, we evaluated the effects of HDACIs on p27Kip1, a key cyclin-dependent kinase inhibitor (CKI). We observed that HDACI-dependent antiproliferative activity is associated with p27Kip1accumulation due to a reduced protein degradation. p27Kip1removal requires a preliminary ubiquitination step due to the Skp2-SCF E3 ligase complex. We demonstrated that HDACIs increase p27Kip1stability through downregulation of Skp2 protein levels. Skp2 decline is only partially due to a reduced Skp2 gene expressio...
Clinical Orthopaedics and Related Research
ABSTRACT
Oncogene
5'-Deoxy-5'methylthioadenosine phosphorylase (MTA-Pase) gene is localized at the 9p21 reg... more 5'-Deoxy-5'methylthioadenosine phosphorylase (MTA-Pase) gene is localized at the 9p21 region linked to the recently identified putative tumor suppressor gene, p16INK4, which appears implicated in the control of cell division cycle. The phosphorylase is a housekeeping enzyme involved in the purine and amino acid metabolism whose activity is evidentiable in all the normal tissues. Chromosomal deletions encompassing both MTAPase and p16INK4 genes cause the total absence of the enzymatic activity only in malignant cells, thus resulting in defined metabolic differences between malignant and normal cells. MTAPase deficiency was investigated by direct radiochemical assay method and by immunochemical techniques in 35 different human malignant cell lines established from several tumor types. The enzyme-deficient cells derived from breast, lung, ovary and liver cancer, malignant melanomas, malignant gliomas and liposarcomas. Two of the MTAPase-deficient cell preparations (from a liver...
Objectives: to characterize the micro- and nano-texture of a novel oxidized titanium implant surf... more Objectives: to characterize the micro- and nano-texture of a novel oxidized titanium implant surface with respect to a conventional turned one, and to evaluate their ability to affect the response of human bone marrow mesenchymal stem cell (BM-MSC) in terms of adhesion, proliferation and osteogenic differentiation. Methods: 10x10x1 mm turned (control) and oxidized (test) titanium samples (P.H.I. s.r.l., San Vittore Olona, Milano, Italy) were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) and characterized by different roughness parameters at different dimensional analysis ranges. Primary cultures of BM-MSC were seeded on titanium samples and cell morphology, adhesion, proliferation and osteogenic differentiation, in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular matrix mineralization, were evaluated. Results: oxidized surfaces showed a more complex micro- and nano-scaled texture with respect to turned ones at both SE...
Journal of Chromatography A, 1988
A high-performance liquid chromatographic (HPLC) method for the separation and purification of 9-... more A high-performance liquid chromatographic (HPLC) method for the separation and purification of 9-[5'-deoxy-5'(methylthio)-beta-D-xylofuranosyl]adenine (xylosyl-MTA), a naturally occurring analogue of 5'-deoxy-5'-methylthioadenosine (MTA), has been developed. The compound was purified from perchloric extracts of biological samples by reversed-phase HPLC on an Ultrasil ODS RP-18 column. Isocratic elution resulted in a complete separation between the xylosyl thioether and MTA. The determination of xylosyl-MTA in the nudibranch mollusc Doris verrucosa was also performed. Its concentration ranged from 330 to 380 nmol/g, considerably exceeding the cellular levels of MTA.
Natural Sulfur Compounds, 1980
Exactly 20 years ago, the presence of methylated amino acid ɛ-N-methyllysine was first discovered... more Exactly 20 years ago, the presence of methylated amino acid ɛ-N-methyllysine was first discovered in the hydrolyzate of flagella protein of Salmonella typhimurium. During the intervening years, it has been recognized that there exist three methylated lysines, ɛ-N-mono-, ɛ-N-di- and ɛ-N-trimethyllysine. In addition, arginine histidine and dicarboxylic amino acid residues of certain proteins were also found to be methylated.
Marine Drugs, 2015
In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble ... more In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC) were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.
Methods in Enzymology, 1983
Bollettino della Società italiana di biologia sperimentale, Jan 15, 1978
Evidences for a phosphorolitic cleavage of 5'-MTA by a specific enzyme from C. acidophila are... more Evidences for a phosphorolitic cleavage of 5'-MTA by a specific enzyme from C. acidophila are reported. Methylthioribose-1-phosphate and adenine have been identified as reaction products, by several analytical procedures.
The Biochemical journal, 1978
5'-Methylthioadenosine phosphorylase was purified approx. 340-fold from human prostate by usi... more 5'-Methylthioadenosine phosphorylase was purified approx. 340-fold from human prostate by using affinity chromatography by Hg-coupled Sepharose. The enzyme, responsible for the breakdown of 5'-methylthioadenosine into adenine and methylthioribose 1-phosphate, was partially characterized. The apparent Km for 5'-methylthioadenosine is 25 microM. It is activated by thiols and shows an absolute requirement for phosphate ions. New analogues of 5'-methylthioadenosine were prepared and their activity as substrates or inhibitors of the reaction was investigated. The replacement of the 6-amino group of the adenine moiety by a hydroxy group, as well as the replacement of N-7 by a methinic radical, resulted in an almost complete loss of activity. Otherwise the replacement of sulphur by selenium, as well as that of the methyl group by an ethyl one, is compatible with the activity as substrate. The positively charged sulphonium group also prevents catalytic interaction with the e...
International journal of immunopathology and pharmacology
Acetylsalicylic acid (ASA) and other non-steroidal anti-inflammatory drugs have been shown to pot... more Acetylsalicylic acid (ASA) and other non-steroidal anti-inflammatory drugs have been shown to potentially inhibit bone healing and bone formation in both animal and clinical studies. Due to the extensive diffusion of ASA-based long-term therapies, the implications of such a side-effect are of interest in all types of bone surgery, including bone grafting procedures and dental implant placement. In this study, we investigate the effect of ASA at therapeutic concentrations on the proliferation and osteogenic differentiation of human bone marrow stromal cells (BMSCs). Primary cultures of BMSCs were isolated and expanded. Their proliferation in response to ASA 50, 100 and 200 microg/ml was evaluated by MTT assay and 3H-thymidine incorporation. Cell cycle machinery was also investigated by FACS and analysis of inhibitors of cyclin-dependent kinases (CDKIs). ASA inhibited BMSC proliferation and DNA synthesis in a dose-dependent manner down to 60% of control (ASA 200 mcg/ml) at 72 h. Cell ...
Molecular and cellular biochemistry, 2003
The importance of bone marrow mesenchymal stem cells in hemopoiesis has been definitely demonstra... more The importance of bone marrow mesenchymal stem cells in hemopoiesis has been definitely demonstrated. Thus, their impairment might cause profound alteration on production and maturation of blood cells. In the present paper, we investigated, for the first time, the effect of retinoic acid, an important antileukemic molecule, on the proliferation of primary cultures of human bone marrow mesenchymal stem cells. We demonstrated that retinoic acid, at a pharmacological concentration, hampers strongly the growth of the cells, without inducing osteoblastic differentiation. The analysis of cell division cycle machinery showed that the antiproliferative effect is associated with (i) the up-regulation of two cyclin-dependent kinase inhibitors, namely p27Kip1 and p16INK4A, and (ii) the down-regulation of cyclin-dependent kinase 2 activity and pRB phosphorylation. The reported findings represent novel insights into the antileukemic effects of the drug and contribute in clarifying the molecular ...
European journal of biochemistry / FEBS, 1980
Kinetic properties of protein methylase I1 (S-adenosy1methionine:protein-carboxyl methyltransfera... more Kinetic properties of protein methylase I1 (S-adenosy1methionine:protein-carboxyl methyltransferase, EC 2.1.1.24), which methylates the free carboxyl groups of protein substrates, were studied with various analogs and derivatives of S-adenosyl-L-methionine (AdoMet) and S-adenosyl-Lhomocysteine (AdoHcy), using corticotropin as methyl-accepting polypeptide. Experiments with methyl-labelled structural analogs of AdoMet showed that the replacement of the amino groups of AdoMet by hydroxyl groups, as well as the removal of the carboxyl group, results in a loss of methylating ability of the molecule. Deaminated and decarboxylated derivatives were also inactive as inhibitors. Among the sulfonium analogs tested, only S-adenosyl-L-(2-amino-4-carboxymethy1thio)butyric acid exerted a significant inhibition. AdoHcy, the demethylated product of AdoMet, exerts a competitive inhibition on the reaction (Ki = 0.65 pM); the probable regulatory role of this inhibition will be discussed. The removal of the adenine amino group of the thioether resulted in a loss of the inhibitory effect. Experiments with the D-isomer of AdoHcy showed the relevance of the steric configuration of the a-carbon in the binding to the enzyme protein. 5'-Methylthioadenosine, a metabolic product of AdoMet, inhibited competitively the reaction (Ki = 41 pM) while 5'-methylthioadenosine derivatives, such as Abbreviations.
Bollettino della Società italiana di biologia sperimentale, Jan 15, 1981
In the present study the effect of 5'methylthioadenosine (MTA), a natural metabolite of S-ade... more In the present study the effect of 5'methylthioadenosine (MTA), a natural metabolite of S-adenosylmethionine (AdoMet), on the enzymatic methyl esterification of intact erythrocyte membrane proteins has been investigated. The thioether significantly affects the methylation process :50% inhibition being observable at 100 microM MTA. This inhibition is due to the action of MTA on the enzyme protein methylase II. Since MTA is present in micromolar amounts in the cells, the reported effect could be of physiological interest and suggests a new regulatory role of this AdoMet metabolite.
The Journal of biological chemistry, Jan 10, 1980
Spermidine synthase (EC 2.5.1.16) purified from Escherichia coli has been subjected to a kinetic ... more Spermidine synthase (EC 2.5.1.16) purified from Escherichia coli has been subjected to a kinetic analysis including initial velocity and substrate analogs inhibition studies. Evidence is reported for a ping-pong mechanism, indicating that a propylaminated form of the enzyme is an obligatory intermediate in the reaction mechanism. S-Adenosyl(5')-3-methylthiopropylamine exerts a competitive substrate inhibition by combining with the improper stable enzyme form, while putrescine does not show any inhibitory effect. In order to investigate the substrate binding sites, new sulfonium-deaminated analogs of S-adenosyl(5')-3-methylthiopropylamine have been synthesized and assayed as substrates and as inhibitors of the reaction. The replacement of the amino group of adenine, or propylamine moiety of the sulfonium compound by the hydroxyl group, or both, resulted in a complete loss of activity as substrate. On the other hand, the deaminated analogs exert a competitive inhibition with r...
The International journal of biochemistry, 1978
ABSTRACT
Oncotarget, 2015
The hope of selectively targeting cancer cells by therapy and eradicating definitively malignanci... more The hope of selectively targeting cancer cells by therapy and eradicating definitively malignancies is based on the identification of pathways or metabolisms that clearly distinguish "normal" from "transformed" phenotypes. Some tyrosine kinase activities, specifically unregulated and potently activated in malignant cells, might represent important targets of therapy. Consequently, tyrosine kinase inhibitors (TKIs) might be thought as the "vanguard" of molecularly targeted therapy for human neoplasias. Imatinib and the successive generations of inhibitors of Bcr-Abl1 kinase, represent the major successful examples of TKI use in cancer treatment. Other tyrosine kinases have been selected as targets of therapy, but the efficacy of their inhibition, although evident, is less definite. Two major negative effects exist in this therapeutic strategy and are linked to the specificity of the drugs and to the role of the targeted kinase in non-malignant cells. In this review, we will discuss the data available on the TKIs effects on the metabolism and functions of mesenchymal stromal cells (MSCs). MSCs are widely distributed in human tissues and play key physiological roles; nevertheless, they might be responsible for important pathologies. At present, bone marrow (BM) MSCs have been studied in greater detail, for both embryological origins and functions. The available data are evocative of an unexpected degree of complexity and heterogeneity of BM-MSCs. It is conceivable that this grade of intricacy occurs also in MSCs of other organs. Therefore, in perspective, the negative effects of TKIs on MSCs might represent a critical problem in long-term cancer therapies based on such inhibitors.
Biochimica et biophysica acta, Jan 3, 2016
Iron overload syndromes include a wide range of diseases frequently associated with increased mor... more Iron overload syndromes include a wide range of diseases frequently associated with increased morbidity and mortality. Several organs are affected in patients with iron overload including liver, heart, joints, endocrine glands, and pancreas. Moreover, severe bone and hemopoietic tissue alterations are observed. Because of the role of bone marrow mesenchymal stromal cells (BM-MSCs) in bone turnover and hematopoiesis, iron effects on primary BM-MSCs cultures were evaluated. Primary human BM-MSCs cultures were prepared and the effects of iron on their proliferation and differentiation were characterized by biochemical analyses and functional approaches. Addition of iron to the culture medium strongly increased BM-MSCs proliferation and induced their accelerated S phase entry. Iron enters BM-MSCs through both transferrin-dependent and transferrin-independent mechanisms, inducing the accumulation of cyclins E and A, the decrease of p27Kip1, and the activation of MAPK pathway. Conversely,...
Oxidative Medicine and Cellular Longevity, 2016
Histone deacetylase inhibitors (HDACIs) represent an intriguing class of pharmacologically active... more Histone deacetylase inhibitors (HDACIs) represent an intriguing class of pharmacologically active compounds. Currently, some HDACIs are FDA approved for cancer therapy and many others are in clinical trials, showing important clinical activities at well tolerated doses. HDACIs also interfere with the aging process and are involved in the control of inflammation and oxidative stress.In vitro, HDACIs induce different cellular responses including growth arrest, differentiation, and apoptosis. Here, we evaluated the effects of HDACIs on p27Kip1, a key cyclin-dependent kinase inhibitor (CKI). We observed that HDACI-dependent antiproliferative activity is associated with p27Kip1accumulation due to a reduced protein degradation. p27Kip1removal requires a preliminary ubiquitination step due to the Skp2-SCF E3 ligase complex. We demonstrated that HDACIs increase p27Kip1stability through downregulation of Skp2 protein levels. Skp2 decline is only partially due to a reduced Skp2 gene expressio...
Clinical Orthopaedics and Related Research
ABSTRACT
Oncogene
5'-Deoxy-5'methylthioadenosine phosphorylase (MTA-Pase) gene is localized at the 9p21 reg... more 5'-Deoxy-5'methylthioadenosine phosphorylase (MTA-Pase) gene is localized at the 9p21 region linked to the recently identified putative tumor suppressor gene, p16INK4, which appears implicated in the control of cell division cycle. The phosphorylase is a housekeeping enzyme involved in the purine and amino acid metabolism whose activity is evidentiable in all the normal tissues. Chromosomal deletions encompassing both MTAPase and p16INK4 genes cause the total absence of the enzymatic activity only in malignant cells, thus resulting in defined metabolic differences between malignant and normal cells. MTAPase deficiency was investigated by direct radiochemical assay method and by immunochemical techniques in 35 different human malignant cell lines established from several tumor types. The enzyme-deficient cells derived from breast, lung, ovary and liver cancer, malignant melanomas, malignant gliomas and liposarcomas. Two of the MTAPase-deficient cell preparations (from a liver...
Objectives: to characterize the micro- and nano-texture of a novel oxidized titanium implant surf... more Objectives: to characterize the micro- and nano-texture of a novel oxidized titanium implant surface with respect to a conventional turned one, and to evaluate their ability to affect the response of human bone marrow mesenchymal stem cell (BM-MSC) in terms of adhesion, proliferation and osteogenic differentiation. Methods: 10x10x1 mm turned (control) and oxidized (test) titanium samples (P.H.I. s.r.l., San Vittore Olona, Milano, Italy) were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) and characterized by different roughness parameters at different dimensional analysis ranges. Primary cultures of BM-MSC were seeded on titanium samples and cell morphology, adhesion, proliferation and osteogenic differentiation, in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular matrix mineralization, were evaluated. Results: oxidized surfaces showed a more complex micro- and nano-scaled texture with respect to turned ones at both SE...
Journal of Chromatography A, 1988
A high-performance liquid chromatographic (HPLC) method for the separation and purification of 9-... more A high-performance liquid chromatographic (HPLC) method for the separation and purification of 9-[5'-deoxy-5'(methylthio)-beta-D-xylofuranosyl]adenine (xylosyl-MTA), a naturally occurring analogue of 5'-deoxy-5'-methylthioadenosine (MTA), has been developed. The compound was purified from perchloric extracts of biological samples by reversed-phase HPLC on an Ultrasil ODS RP-18 column. Isocratic elution resulted in a complete separation between the xylosyl thioether and MTA. The determination of xylosyl-MTA in the nudibranch mollusc Doris verrucosa was also performed. Its concentration ranged from 330 to 380 nmol/g, considerably exceeding the cellular levels of MTA.
Natural Sulfur Compounds, 1980
Exactly 20 years ago, the presence of methylated amino acid ɛ-N-methyllysine was first discovered... more Exactly 20 years ago, the presence of methylated amino acid ɛ-N-methyllysine was first discovered in the hydrolyzate of flagella protein of Salmonella typhimurium. During the intervening years, it has been recognized that there exist three methylated lysines, ɛ-N-mono-, ɛ-N-di- and ɛ-N-trimethyllysine. In addition, arginine histidine and dicarboxylic amino acid residues of certain proteins were also found to be methylated.
Marine Drugs, 2015
In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble ... more In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC) were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.
Methods in Enzymology, 1983
Bollettino della Società italiana di biologia sperimentale, Jan 15, 1978
Evidences for a phosphorolitic cleavage of 5'-MTA by a specific enzyme from C. acidophila are... more Evidences for a phosphorolitic cleavage of 5'-MTA by a specific enzyme from C. acidophila are reported. Methylthioribose-1-phosphate and adenine have been identified as reaction products, by several analytical procedures.
The Biochemical journal, 1978
5'-Methylthioadenosine phosphorylase was purified approx. 340-fold from human prostate by usi... more 5'-Methylthioadenosine phosphorylase was purified approx. 340-fold from human prostate by using affinity chromatography by Hg-coupled Sepharose. The enzyme, responsible for the breakdown of 5'-methylthioadenosine into adenine and methylthioribose 1-phosphate, was partially characterized. The apparent Km for 5'-methylthioadenosine is 25 microM. It is activated by thiols and shows an absolute requirement for phosphate ions. New analogues of 5'-methylthioadenosine were prepared and their activity as substrates or inhibitors of the reaction was investigated. The replacement of the 6-amino group of the adenine moiety by a hydroxy group, as well as the replacement of N-7 by a methinic radical, resulted in an almost complete loss of activity. Otherwise the replacement of sulphur by selenium, as well as that of the methyl group by an ethyl one, is compatible with the activity as substrate. The positively charged sulphonium group also prevents catalytic interaction with the e...
International journal of immunopathology and pharmacology
Acetylsalicylic acid (ASA) and other non-steroidal anti-inflammatory drugs have been shown to pot... more Acetylsalicylic acid (ASA) and other non-steroidal anti-inflammatory drugs have been shown to potentially inhibit bone healing and bone formation in both animal and clinical studies. Due to the extensive diffusion of ASA-based long-term therapies, the implications of such a side-effect are of interest in all types of bone surgery, including bone grafting procedures and dental implant placement. In this study, we investigate the effect of ASA at therapeutic concentrations on the proliferation and osteogenic differentiation of human bone marrow stromal cells (BMSCs). Primary cultures of BMSCs were isolated and expanded. Their proliferation in response to ASA 50, 100 and 200 microg/ml was evaluated by MTT assay and 3H-thymidine incorporation. Cell cycle machinery was also investigated by FACS and analysis of inhibitors of cyclin-dependent kinases (CDKIs). ASA inhibited BMSC proliferation and DNA synthesis in a dose-dependent manner down to 60% of control (ASA 200 mcg/ml) at 72 h. Cell ...
Molecular and cellular biochemistry, 2003
The importance of bone marrow mesenchymal stem cells in hemopoiesis has been definitely demonstra... more The importance of bone marrow mesenchymal stem cells in hemopoiesis has been definitely demonstrated. Thus, their impairment might cause profound alteration on production and maturation of blood cells. In the present paper, we investigated, for the first time, the effect of retinoic acid, an important antileukemic molecule, on the proliferation of primary cultures of human bone marrow mesenchymal stem cells. We demonstrated that retinoic acid, at a pharmacological concentration, hampers strongly the growth of the cells, without inducing osteoblastic differentiation. The analysis of cell division cycle machinery showed that the antiproliferative effect is associated with (i) the up-regulation of two cyclin-dependent kinase inhibitors, namely p27Kip1 and p16INK4A, and (ii) the down-regulation of cyclin-dependent kinase 2 activity and pRB phosphorylation. The reported findings represent novel insights into the antileukemic effects of the drug and contribute in clarifying the molecular ...
European journal of biochemistry / FEBS, 1980
Kinetic properties of protein methylase I1 (S-adenosy1methionine:protein-carboxyl methyltransfera... more Kinetic properties of protein methylase I1 (S-adenosy1methionine:protein-carboxyl methyltransferase, EC 2.1.1.24), which methylates the free carboxyl groups of protein substrates, were studied with various analogs and derivatives of S-adenosyl-L-methionine (AdoMet) and S-adenosyl-Lhomocysteine (AdoHcy), using corticotropin as methyl-accepting polypeptide. Experiments with methyl-labelled structural analogs of AdoMet showed that the replacement of the amino groups of AdoMet by hydroxyl groups, as well as the removal of the carboxyl group, results in a loss of methylating ability of the molecule. Deaminated and decarboxylated derivatives were also inactive as inhibitors. Among the sulfonium analogs tested, only S-adenosyl-L-(2-amino-4-carboxymethy1thio)butyric acid exerted a significant inhibition. AdoHcy, the demethylated product of AdoMet, exerts a competitive inhibition on the reaction (Ki = 0.65 pM); the probable regulatory role of this inhibition will be discussed. The removal of the adenine amino group of the thioether resulted in a loss of the inhibitory effect. Experiments with the D-isomer of AdoHcy showed the relevance of the steric configuration of the a-carbon in the binding to the enzyme protein. 5'-Methylthioadenosine, a metabolic product of AdoMet, inhibited competitively the reaction (Ki = 41 pM) while 5'-methylthioadenosine derivatives, such as Abbreviations.
Bollettino della Società italiana di biologia sperimentale, Jan 15, 1981
In the present study the effect of 5'methylthioadenosine (MTA), a natural metabolite of S-ade... more In the present study the effect of 5'methylthioadenosine (MTA), a natural metabolite of S-adenosylmethionine (AdoMet), on the enzymatic methyl esterification of intact erythrocyte membrane proteins has been investigated. The thioether significantly affects the methylation process :50% inhibition being observable at 100 microM MTA. This inhibition is due to the action of MTA on the enzyme protein methylase II. Since MTA is present in micromolar amounts in the cells, the reported effect could be of physiological interest and suggests a new regulatory role of this AdoMet metabolite.
The Journal of biological chemistry, Jan 10, 1980
Spermidine synthase (EC 2.5.1.16) purified from Escherichia coli has been subjected to a kinetic ... more Spermidine synthase (EC 2.5.1.16) purified from Escherichia coli has been subjected to a kinetic analysis including initial velocity and substrate analogs inhibition studies. Evidence is reported for a ping-pong mechanism, indicating that a propylaminated form of the enzyme is an obligatory intermediate in the reaction mechanism. S-Adenosyl(5')-3-methylthiopropylamine exerts a competitive substrate inhibition by combining with the improper stable enzyme form, while putrescine does not show any inhibitory effect. In order to investigate the substrate binding sites, new sulfonium-deaminated analogs of S-adenosyl(5')-3-methylthiopropylamine have been synthesized and assayed as substrates and as inhibitors of the reaction. The replacement of the amino group of adenine, or propylamine moiety of the sulfonium compound by the hydroxyl group, or both, resulted in a complete loss of activity as substrate. On the other hand, the deaminated analogs exert a competitive inhibition with r...
The International journal of biochemistry, 1978
ABSTRACT