Concettina Cappadone - Academia.edu (original) (raw)
Papers by Concettina Cappadone
International Journal of Molecular Sciences
Osteosarcoma (OS) is the most common primary malignant bone tumor and its etiology has recently b... more Osteosarcoma (OS) is the most common primary malignant bone tumor and its etiology has recently been associated with osteogenic differentiation dysfunctions. OS cells keep a capacity for uncontrolled proliferation showing a phenotype similar to undifferentiated osteoprogenitors with abnormal biomineralization. Within this context, both conventional and X-ray synchrotron-based techniques have been exploited to deeply characterize the genesis and evolution of mineral depositions in a human OS cell line (SaOS-2) exposed to an osteogenic cocktail for 4 and 10 days. A partial restoration of the physiological biomineralization, culminating with the formation of hydroxyapatite, was observed at 10 days after treatment together with a mitochondria-driven mechanism for calcium transportation within the cell. Interestingly, during differentiation, mitochondria showed a change in morphology from elongated to rounded, indicating a metabolic reprogramming of OS cells possibly linked to an increas...
Antibiotics
In recent years, the treatment of bacterial skin infections has been considered a major healthcar... more In recent years, the treatment of bacterial skin infections has been considered a major healthcare issue due to the growing emergence of antibiotic-resistant strains of Staphylococcus aureus. The incorporation of antibiotics in appropriate nanosystems could represent a promising strategy, able to overcome several drawbacks of the topical treatment of infections, including poor drug retention within the skin. The present work aims to develop microemulsions containing azithromycin (AZT), a broad-spectrum macrolide antibiotic. Firstly, AZT solubility in various oils, surfactants and co-surfactants was assessed to select the main components. Subsequently, microemulsions composed of vitamin E acetate, Labrasol® and Transcutol® P were prepared and characterized for their pH, viscosity, droplet size, zeta potential and ability to release the drug and to promote its retention inside porcine skin. Antimicrobial activity against S. aureus methicillin-resistant strains (MRSA) and the biocompat...
Magnesium Research
The role of magnesium in cell metabolism is complex and still not completely clarified. Although ... more The role of magnesium in cell metabolism is complex and still not completely clarified. Although magnesium has been shown to modulate many phenomena in cells, its intracellular distribution and subcellular compartmentalization have not yet elucidated in detail, mainly as a consequence of the inadequacy of analytical techniques. The method usually employed to quantify total magnesium in cells or tissue are F-AAS or more sensitive techniques as graphite furnace AAS and inductively coupled plasma mass spectroscopy (MS). Thanks to the development of new specific fluorescent dyes, several progresses have been made in the comprehension of the fundamental biological process at the cellular and sub-cellular level. Moreover, the biological function of a chemical element in cells does not only require the determination of its intracellular quantity but also the spatial distribution of its concentration. Most of Mg2+-sensitive fluorescent dyes detect only the free metal ions, precluding the possibility of identifying the total pool of Mg. This review aims at giving an overview on different techniques focusing on two approaches to quantify total Mg in a small cell population or in single cells: i) Indirect Mg detection, label-based methods that represent the best choice to quantify the elemental concentration on a large cell population; ii) direct Mg detection (label-free), Synchrotron-based x-ray microscopy techniques that offer the possibility of achieving a detailed map of the intracellular concentration of a specific chemical element on single cell.
Molecules
Osteosarcoma (OS) is a malignant disease characterized by poor prognosis due to a high incidence ... more Osteosarcoma (OS) is a malignant disease characterized by poor prognosis due to a high incidence of metastasis and chemoresistance. Recently, Licochalcone A (Lic-A) has been reported as a promising agent against OS. Starting from chalcones selected from a wide in-house library, a new series was designed and synthetized. The antitumor activity of the compounds was tested on the MG63 OS cell line through the innovative Quantitative Phase Imaging technique and MTT assay. To further investigate the biological profile of active derivatives, cell cycle progression and apoptosis induction were evaluated. An earlier and more consistent arrest in the G2-M phase with respect to Lic-A was observed. Moreover, apoptosis was assessed by Annexin V staining as well as by the detection of typical morphological features of apoptotic cells. Among the selected compounds, 1e, 1q, and 1r proved to be the most promising antitumor molecules. This study pointed out that an integrated methodological approach...
6° Meeting Nuove prospettive in Chimica Farmaceutica, 2012
0 20 25 30 35 40 45 50 F lu or es ce nc e In te ns ity /a .u . 20 25 30 35 40 45 50 F lu or es ce... more 0 20 25 30 35 40 45 50 F lu or es ce nc e In te ns ity /a .u . 20 25 30 35 40 45 50 F lu or es ce nc e In te ns ity /a .u . B A
International journal of molecular sciences, Jan 9, 2018
Magnesium plays a pivotal role in energy metabolism and in the control of cell growth. While magn... more Magnesium plays a pivotal role in energy metabolism and in the control of cell growth. While magnesium deprivation clearly shapes the behavior of normal and neoplastic cells, little is known on the role of this element in cell differentiation. Here we show that magnesium deficiency increases the transcription of multipotency markers and tissue-specific transcription factors in human adipose-derived mesenchymal stem cells exposed to a mixture of natural molecules, i.e., hyaluronic, butyric and retinoid acids, which tunes differentiation. We also demonstrate that magnesium deficiency accelerates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. We argue that magnesium deprivation generates a stressful condition that modulates stem cell plasticity and differentiation potential. These studies indicate that it is possible to remodel transcription in mesenchymal stem cells by lowering extracellular magnesium without the need for genetic manipulation, thus...
Magnesium research : official organ of the International Society for the Development of Research on Magnesium
The differing bioavailability of magnesium salts remains an open question, both at the cellular a... more The differing bioavailability of magnesium salts remains an open question, both at the cellular and systemic level. However, this issue is relevant for identifying the most effective magnesium supplement. We compared the effects of three widely used magnesium salts: MgSO4, MgCl2 and Mg pidolate, on the proliferation of four human cell types: promyelocytic leukaemia HL60, osteoblast-like Saos-2 and U-2 OS, and endothelial cells from the umbilical vein. The three magnesium salts had no effect on endothelial and leukemic cell growth, but magnesium pidolate impaired cell growth in osteoblast-like cells. In particular, in Saos-2 cells, 1 mM pidolate induced a slight accumulation of cells in the G0/G1 phase of the cell cycle and, in parallel, an early rise in intracellular calcium and a late decrease in intracellular magnesium content. Interestingly, when cultured in 5 mM magnesium pidolate, Saos-2 cells grew as fast as the controls. Moreover, intracellular magnesium and calcium concentra...
INTRODUCTION: 4-Hydroxynonenal (HNE) a diffusible product of lipid peroxidation, has been suggest... more INTRODUCTION: 4-Hydroxynonenal (HNE) a diffusible product of lipid peroxidation, has been suggested to act as a key mediator in oxidative stress-induced cell death. Exogenously administrated HNE can form protein adducts and cause apoptotic cell death in various cell types. Previously we demonstrated that in a human osteosarcoma cell line, SaOS2, HNE 10#mu#M exhibits an early cytotoxic effect characterized by apoptosis, and cytostatic and differentiating effects characterized by slow growth, increase in alkaline phosphatase and decrease in tumorigenicity[1]. The aim of this study is investigate HNE cytotoxic effects more in depth by analyzing cell distribution in the cell cycle phases, the expression levels of proteins involved in cell growth regulation, the internucleosomal cleavage of DNA, and LDH activity to evaluate necrotic events. MATERIALS AND METHODS SaOS2 cells were seeded at 2x10#A4# cells/cm#A2# and treated with 10#mu#M HNE[1]. Samples stained with PI as DNA probe were analysed by flow cytometry to assess the cell cycle distribution. P21 expression levels were evaluated in Western Blot. The DNA laddering was revealed according to Mc.Conkey [2]. The LDH activity was monitored spectrophotometrically by measuring NADH levels. RESULTS The treatment with HNE 10#mu#M after 24hrs causes an accumulation of osteosarcoma cells in S and in G2/M. Such an effect on the cell cycle may be related to the increased levels of the CDK-inhibitor p21, as shown by western blot analysis. Although specific morphological characteristic of apoptotic cells were reported in literature for SaOS2 treated with HNE, internucleosomal DNA fragmentation, was not found in agarose gel electrophoresis. The measurament of the LDH release in the medium showed the membrane integrity of treated cells. In conclusion HNE-induced cytotoxyc effect in SaOS2 cells is characterized by a growth arrest in the S and G2/M phases, coupled with p21 increased expression. HNE-exerted cell death is an atypical apoptosis because it doesn\u2019t show the classical DNA laddering. On the other hand the absence of LDH activity in the medium excludes that the induced cell death can result in necrosis. References [1] Calonghi N. et al.BBRC 293 (2002) 1502-1507 [2] Mc Conkey DJ. et al. Arch.Biochim.Biophys.Acta 972 (1989) 302-31
Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale, 2014
A recent study showed the antitumor activity of a new indole-derivative – MM-67 – inducing mitoch... more A recent study showed the antitumor activity of a new indole-derivative – MM-67 – inducing mitochondria-mediated apoptosis and a decrease of intracellular magnesium (Mg) concentration in HT29 colon cancer cells. Aim of this work was to assess cellular Mg levels throughout MM-67-induced apoptosis from the early to the final stage of the process and to evaluate the correlation with mitochondrial membrane potential (ΔΨm) variations. All analysis were performed by flow cytometry: ΔΨm was assessed by using mitochondrial potential sensitive dye DiOC6, while free and total intracellular cation concentrations were assessed by using the commercial probe MagFluo4-AM (Kd=4.7 mM), and the new synthesized DCHQ5 (Kd=8.3 mM), respectively. Our results evidenced that the MM67 induced apoptosis is characterized by a direct correlation between ΔΨ and free intracellular Mg content variations.
Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale, 2014
Cellular homeostasis of magnesium is still unclear. Several studies documented the occurrence of ... more Cellular homeostasis of magnesium is still unclear. Several studies documented the occurrence of fluxes of magnesium across the plasmamembrane within minutes from the application of metabolic or hormonal stimuli. These fluxes, however, result in limited variation of free Mg2+ intracellular concentration and large changes in total Mg content. It has been reported that a stimulation with cyclic AMP caused a movement of total magnesium within 10 min after treatment in cardiomyocytes. In this study we tested this hypothesis in HL60 leukemic cells, not excitable but highly proliferating cell model. We evaluated Mg flux by DCHQ5, the phenyl-derivative of hydroxyquinoline fluorescent probe family. We observed a drastic decrease of intracellular total magnesium in the first 3 min. We also verified that at least 10% of the total intracellular amount of magnesium moved in the supernatant of stimulated cells.
Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale, 2014
Magnesium (Mg) plays crucial structural and regulatory roles within cells. Despite the extensive ... more Magnesium (Mg) plays crucial structural and regulatory roles within cells. Despite the extensive amount of data about the biochemistry of Mg, a complete picture of its regulation and cellular homeostasis is lacking. Thanks to recent improvements in third generation synchrotron X-ray sources, X-ray fluorescence microscopy (XRFM) is becoming a highly sensitive method for mapping elemental distributions in cells. XRFM maps the element content but not the concentration, which is a relevant variable in a biological context. We tackled this issue by combining XRFM with atomic force microscopy that was used to obtain morphological information of the sample. The aim of the present study was to compare the content and the distribution of Mg in drug-resistant and -sensitive tumor cell lines. Our data has shown a massive increase of Mg in LoVo drug-resistant cells. Moreover, the map of intracellular Mg showed marked differences in the pattern distribution between sensitive and resistant cells.
The Analyst, 2014
Remarkable features of a novel fluorescent Mg dye: high fluorescence intensity and intracellular ... more Remarkable features of a novel fluorescent Mg dye: high fluorescence intensity and intracellular retention.
![Research paper thumbnail of Substituted 3-(5-Imidazo[2,1-b]thiazolylmethylene)-2-indolinones and Analogues: Synthesis, Cytotoxic Activity, and Study of the Mechanism of Action](https://attachments.academia-assets.com/101588345/thumbnails/1.jpg)
](Journal of Medicinal Chemistry, 2012
The synthesis of substituted 3-(5-imidazo[2,1-b]thiazolylmethylene)-2-indolinones and analogues i... more The synthesis of substituted 3-(5-imidazo[2,1-b]thiazolylmethylene)-2-indolinones and analogues is reported. Their cytotoxic activity was evaluated according to protocols available at the National Cancer Institute (NCI), Bethesda, MD. The action of selected compounds was examined for potential inhibition of tubulin assembly in comparison with the potent colchicine site agent combretastatin A-4. The most potent compounds also strongly and selectively inhibited the phosphorylation of the oncoprotein kinase Akt in cancer cells. The effect of the most interesting compounds was examined on the growth of HT-29 colon cancer cells. These compounds caused the cells to arrest in the G2/M phase of the cell cycle, as would be expected for inhibitors of tubulin assembly.
Analytical Chemistry, 2014
We report a method that allows a complete quantitative characterization of whole single cells, as... more We report a method that allows a complete quantitative characterization of whole single cells, assessing the total amount of carbon, nitrogen, oxygen, sodium, and magnesium and providing submicrometer maps of element molar concentration, cell density, mass, and volume. This approach allows quantifying elements down to 10 6 atoms/μm 3. This result was obtained by applying a multimodal fusion approach that combines synchrotron radiation microscopy techniques with off-line atomic force microscopy. The method proposed permits us to find the element concentration in addition to the mass fraction and provides a deeper and more complete knowledge of cell composition. We performed measurements on LoVo human colon cancer cells sensitive (LoVo-S) and resistant (LoVo-R) to doxorubicin. The comparison of LoVo-S and LoVo-R revealed different patterns in the maps of Mg concentration with higher values within the nucleus in LoVo-R and in the perinuclear region in LoVo-S cells. This feature was not so evident for the other elements, suggesting that Mg compartmentalization could be a significant trait of the drug-resistant cells.
ABSTRACT We present here a new methodology for quantitative mapping of light elements in cells, b... more ABSTRACT We present here a new methodology for quantitative mapping of light elements in cells, based on combination of compositional and morphological information, derived respectively by X-ray Fluorescence Microscopy (XRFM), Atomic Force Microscopy and Scanning Transmission X-ray Microscopy (STXM). Since XRFM of light elements (carbon, nitrogen, oxygen, sodium and magnesium), are strongly influenced by self-absorption, we developed an algorithm to correct for this effect, using the morphological and structural information provided by AFM and STXM. Finally, the corrected distributions have been obtained, thus allowing quantitative mapping.
SIB 2009, 54th Meeting of the Italian Society of Biochemistry and Molecular Biology (SIB), 2009
SIB 2009, 54th Meeting of the Italian Society of Biochemistry and Molecular Biology, 2009
International Journal of Molecular Sciences
Osteosarcoma (OS) is the most common primary malignant bone tumor and its etiology has recently b... more Osteosarcoma (OS) is the most common primary malignant bone tumor and its etiology has recently been associated with osteogenic differentiation dysfunctions. OS cells keep a capacity for uncontrolled proliferation showing a phenotype similar to undifferentiated osteoprogenitors with abnormal biomineralization. Within this context, both conventional and X-ray synchrotron-based techniques have been exploited to deeply characterize the genesis and evolution of mineral depositions in a human OS cell line (SaOS-2) exposed to an osteogenic cocktail for 4 and 10 days. A partial restoration of the physiological biomineralization, culminating with the formation of hydroxyapatite, was observed at 10 days after treatment together with a mitochondria-driven mechanism for calcium transportation within the cell. Interestingly, during differentiation, mitochondria showed a change in morphology from elongated to rounded, indicating a metabolic reprogramming of OS cells possibly linked to an increas...
Antibiotics
In recent years, the treatment of bacterial skin infections has been considered a major healthcar... more In recent years, the treatment of bacterial skin infections has been considered a major healthcare issue due to the growing emergence of antibiotic-resistant strains of Staphylococcus aureus. The incorporation of antibiotics in appropriate nanosystems could represent a promising strategy, able to overcome several drawbacks of the topical treatment of infections, including poor drug retention within the skin. The present work aims to develop microemulsions containing azithromycin (AZT), a broad-spectrum macrolide antibiotic. Firstly, AZT solubility in various oils, surfactants and co-surfactants was assessed to select the main components. Subsequently, microemulsions composed of vitamin E acetate, Labrasol® and Transcutol® P were prepared and characterized for their pH, viscosity, droplet size, zeta potential and ability to release the drug and to promote its retention inside porcine skin. Antimicrobial activity against S. aureus methicillin-resistant strains (MRSA) and the biocompat...
Magnesium Research
The role of magnesium in cell metabolism is complex and still not completely clarified. Although ... more The role of magnesium in cell metabolism is complex and still not completely clarified. Although magnesium has been shown to modulate many phenomena in cells, its intracellular distribution and subcellular compartmentalization have not yet elucidated in detail, mainly as a consequence of the inadequacy of analytical techniques. The method usually employed to quantify total magnesium in cells or tissue are F-AAS or more sensitive techniques as graphite furnace AAS and inductively coupled plasma mass spectroscopy (MS). Thanks to the development of new specific fluorescent dyes, several progresses have been made in the comprehension of the fundamental biological process at the cellular and sub-cellular level. Moreover, the biological function of a chemical element in cells does not only require the determination of its intracellular quantity but also the spatial distribution of its concentration. Most of Mg2+-sensitive fluorescent dyes detect only the free metal ions, precluding the possibility of identifying the total pool of Mg. This review aims at giving an overview on different techniques focusing on two approaches to quantify total Mg in a small cell population or in single cells: i) Indirect Mg detection, label-based methods that represent the best choice to quantify the elemental concentration on a large cell population; ii) direct Mg detection (label-free), Synchrotron-based x-ray microscopy techniques that offer the possibility of achieving a detailed map of the intracellular concentration of a specific chemical element on single cell.
Molecules
Osteosarcoma (OS) is a malignant disease characterized by poor prognosis due to a high incidence ... more Osteosarcoma (OS) is a malignant disease characterized by poor prognosis due to a high incidence of metastasis and chemoresistance. Recently, Licochalcone A (Lic-A) has been reported as a promising agent against OS. Starting from chalcones selected from a wide in-house library, a new series was designed and synthetized. The antitumor activity of the compounds was tested on the MG63 OS cell line through the innovative Quantitative Phase Imaging technique and MTT assay. To further investigate the biological profile of active derivatives, cell cycle progression and apoptosis induction were evaluated. An earlier and more consistent arrest in the G2-M phase with respect to Lic-A was observed. Moreover, apoptosis was assessed by Annexin V staining as well as by the detection of typical morphological features of apoptotic cells. Among the selected compounds, 1e, 1q, and 1r proved to be the most promising antitumor molecules. This study pointed out that an integrated methodological approach...
6° Meeting Nuove prospettive in Chimica Farmaceutica, 2012
0 20 25 30 35 40 45 50 F lu or es ce nc e In te ns ity /a .u . 20 25 30 35 40 45 50 F lu or es ce... more 0 20 25 30 35 40 45 50 F lu or es ce nc e In te ns ity /a .u . 20 25 30 35 40 45 50 F lu or es ce nc e In te ns ity /a .u . B A
International journal of molecular sciences, Jan 9, 2018
Magnesium plays a pivotal role in energy metabolism and in the control of cell growth. While magn... more Magnesium plays a pivotal role in energy metabolism and in the control of cell growth. While magnesium deprivation clearly shapes the behavior of normal and neoplastic cells, little is known on the role of this element in cell differentiation. Here we show that magnesium deficiency increases the transcription of multipotency markers and tissue-specific transcription factors in human adipose-derived mesenchymal stem cells exposed to a mixture of natural molecules, i.e., hyaluronic, butyric and retinoid acids, which tunes differentiation. We also demonstrate that magnesium deficiency accelerates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. We argue that magnesium deprivation generates a stressful condition that modulates stem cell plasticity and differentiation potential. These studies indicate that it is possible to remodel transcription in mesenchymal stem cells by lowering extracellular magnesium without the need for genetic manipulation, thus...
Magnesium research : official organ of the International Society for the Development of Research on Magnesium
The differing bioavailability of magnesium salts remains an open question, both at the cellular a... more The differing bioavailability of magnesium salts remains an open question, both at the cellular and systemic level. However, this issue is relevant for identifying the most effective magnesium supplement. We compared the effects of three widely used magnesium salts: MgSO4, MgCl2 and Mg pidolate, on the proliferation of four human cell types: promyelocytic leukaemia HL60, osteoblast-like Saos-2 and U-2 OS, and endothelial cells from the umbilical vein. The three magnesium salts had no effect on endothelial and leukemic cell growth, but magnesium pidolate impaired cell growth in osteoblast-like cells. In particular, in Saos-2 cells, 1 mM pidolate induced a slight accumulation of cells in the G0/G1 phase of the cell cycle and, in parallel, an early rise in intracellular calcium and a late decrease in intracellular magnesium content. Interestingly, when cultured in 5 mM magnesium pidolate, Saos-2 cells grew as fast as the controls. Moreover, intracellular magnesium and calcium concentra...
INTRODUCTION: 4-Hydroxynonenal (HNE) a diffusible product of lipid peroxidation, has been suggest... more INTRODUCTION: 4-Hydroxynonenal (HNE) a diffusible product of lipid peroxidation, has been suggested to act as a key mediator in oxidative stress-induced cell death. Exogenously administrated HNE can form protein adducts and cause apoptotic cell death in various cell types. Previously we demonstrated that in a human osteosarcoma cell line, SaOS2, HNE 10#mu#M exhibits an early cytotoxic effect characterized by apoptosis, and cytostatic and differentiating effects characterized by slow growth, increase in alkaline phosphatase and decrease in tumorigenicity[1]. The aim of this study is investigate HNE cytotoxic effects more in depth by analyzing cell distribution in the cell cycle phases, the expression levels of proteins involved in cell growth regulation, the internucleosomal cleavage of DNA, and LDH activity to evaluate necrotic events. MATERIALS AND METHODS SaOS2 cells were seeded at 2x10#A4# cells/cm#A2# and treated with 10#mu#M HNE[1]. Samples stained with PI as DNA probe were analysed by flow cytometry to assess the cell cycle distribution. P21 expression levels were evaluated in Western Blot. The DNA laddering was revealed according to Mc.Conkey [2]. The LDH activity was monitored spectrophotometrically by measuring NADH levels. RESULTS The treatment with HNE 10#mu#M after 24hrs causes an accumulation of osteosarcoma cells in S and in G2/M. Such an effect on the cell cycle may be related to the increased levels of the CDK-inhibitor p21, as shown by western blot analysis. Although specific morphological characteristic of apoptotic cells were reported in literature for SaOS2 treated with HNE, internucleosomal DNA fragmentation, was not found in agarose gel electrophoresis. The measurament of the LDH release in the medium showed the membrane integrity of treated cells. In conclusion HNE-induced cytotoxyc effect in SaOS2 cells is characterized by a growth arrest in the S and G2/M phases, coupled with p21 increased expression. HNE-exerted cell death is an atypical apoptosis because it doesn\u2019t show the classical DNA laddering. On the other hand the absence of LDH activity in the medium excludes that the induced cell death can result in necrosis. References [1] Calonghi N. et al.BBRC 293 (2002) 1502-1507 [2] Mc Conkey DJ. et al. Arch.Biochim.Biophys.Acta 972 (1989) 302-31
Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale, 2014
A recent study showed the antitumor activity of a new indole-derivative – MM-67 – inducing mitoch... more A recent study showed the antitumor activity of a new indole-derivative – MM-67 – inducing mitochondria-mediated apoptosis and a decrease of intracellular magnesium (Mg) concentration in HT29 colon cancer cells. Aim of this work was to assess cellular Mg levels throughout MM-67-induced apoptosis from the early to the final stage of the process and to evaluate the correlation with mitochondrial membrane potential (ΔΨm) variations. All analysis were performed by flow cytometry: ΔΨm was assessed by using mitochondrial potential sensitive dye DiOC6, while free and total intracellular cation concentrations were assessed by using the commercial probe MagFluo4-AM (Kd=4.7 mM), and the new synthesized DCHQ5 (Kd=8.3 mM), respectively. Our results evidenced that the MM67 induced apoptosis is characterized by a direct correlation between ΔΨ and free intracellular Mg content variations.
Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale, 2014
Cellular homeostasis of magnesium is still unclear. Several studies documented the occurrence of ... more Cellular homeostasis of magnesium is still unclear. Several studies documented the occurrence of fluxes of magnesium across the plasmamembrane within minutes from the application of metabolic or hormonal stimuli. These fluxes, however, result in limited variation of free Mg2+ intracellular concentration and large changes in total Mg content. It has been reported that a stimulation with cyclic AMP caused a movement of total magnesium within 10 min after treatment in cardiomyocytes. In this study we tested this hypothesis in HL60 leukemic cells, not excitable but highly proliferating cell model. We evaluated Mg flux by DCHQ5, the phenyl-derivative of hydroxyquinoline fluorescent probe family. We observed a drastic decrease of intracellular total magnesium in the first 3 min. We also verified that at least 10% of the total intracellular amount of magnesium moved in the supernatant of stimulated cells.
Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale, 2014
Magnesium (Mg) plays crucial structural and regulatory roles within cells. Despite the extensive ... more Magnesium (Mg) plays crucial structural and regulatory roles within cells. Despite the extensive amount of data about the biochemistry of Mg, a complete picture of its regulation and cellular homeostasis is lacking. Thanks to recent improvements in third generation synchrotron X-ray sources, X-ray fluorescence microscopy (XRFM) is becoming a highly sensitive method for mapping elemental distributions in cells. XRFM maps the element content but not the concentration, which is a relevant variable in a biological context. We tackled this issue by combining XRFM with atomic force microscopy that was used to obtain morphological information of the sample. The aim of the present study was to compare the content and the distribution of Mg in drug-resistant and -sensitive tumor cell lines. Our data has shown a massive increase of Mg in LoVo drug-resistant cells. Moreover, the map of intracellular Mg showed marked differences in the pattern distribution between sensitive and resistant cells.
The Analyst, 2014
Remarkable features of a novel fluorescent Mg dye: high fluorescence intensity and intracellular ... more Remarkable features of a novel fluorescent Mg dye: high fluorescence intensity and intracellular retention.
Journal of Medicinal Chemistry, 2012
The synthesis of substituted 3-(5-imidazo[2,1-b]thiazolylmethylene)-2-indolinones and analogues i... more The synthesis of substituted 3-(5-imidazo[2,1-b]thiazolylmethylene)-2-indolinones and analogues is reported. Their cytotoxic activity was evaluated according to protocols available at the National Cancer Institute (NCI), Bethesda, MD. The action of selected compounds was examined for potential inhibition of tubulin assembly in comparison with the potent colchicine site agent combretastatin A-4. The most potent compounds also strongly and selectively inhibited the phosphorylation of the oncoprotein kinase Akt in cancer cells. The effect of the most interesting compounds was examined on the growth of HT-29 colon cancer cells. These compounds caused the cells to arrest in the G2/M phase of the cell cycle, as would be expected for inhibitors of tubulin assembly.
Analytical Chemistry, 2014
We report a method that allows a complete quantitative characterization of whole single cells, as... more We report a method that allows a complete quantitative characterization of whole single cells, assessing the total amount of carbon, nitrogen, oxygen, sodium, and magnesium and providing submicrometer maps of element molar concentration, cell density, mass, and volume. This approach allows quantifying elements down to 10 6 atoms/μm 3. This result was obtained by applying a multimodal fusion approach that combines synchrotron radiation microscopy techniques with off-line atomic force microscopy. The method proposed permits us to find the element concentration in addition to the mass fraction and provides a deeper and more complete knowledge of cell composition. We performed measurements on LoVo human colon cancer cells sensitive (LoVo-S) and resistant (LoVo-R) to doxorubicin. The comparison of LoVo-S and LoVo-R revealed different patterns in the maps of Mg concentration with higher values within the nucleus in LoVo-R and in the perinuclear region in LoVo-S cells. This feature was not so evident for the other elements, suggesting that Mg compartmentalization could be a significant trait of the drug-resistant cells.
ABSTRACT We present here a new methodology for quantitative mapping of light elements in cells, b... more ABSTRACT We present here a new methodology for quantitative mapping of light elements in cells, based on combination of compositional and morphological information, derived respectively by X-ray Fluorescence Microscopy (XRFM), Atomic Force Microscopy and Scanning Transmission X-ray Microscopy (STXM). Since XRFM of light elements (carbon, nitrogen, oxygen, sodium and magnesium), are strongly influenced by self-absorption, we developed an algorithm to correct for this effect, using the morphological and structural information provided by AFM and STXM. Finally, the corrected distributions have been obtained, thus allowing quantitative mapping.
SIB 2009, 54th Meeting of the Italian Society of Biochemistry and Molecular Biology (SIB), 2009
SIB 2009, 54th Meeting of the Italian Society of Biochemistry and Molecular Biology, 2009