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Biomedical subjects

M Ruggiero

Publications and source records attributed to M Ruggiero.

At least 19 recordsLinked to original sources
PubMed1996

In vitro effects of some differentiation inductors in metaplastic epithelium of the human nasal cavity.

The alterations in the mucociliary unit in the course of chronic inflammation of the upper respiratory tract correspond to morphologic anomalies of the respiratory epithelium and induce cuboidal and squamous metaplasia. While the squamous pattern is most probably irreversible, it is still not clear whether it is possible to restore ciliogenesis in cuboidal metaplasia. In the present study, the action of different inductors of differentiation was evaluated in vitro in isolated cells and explants from human nasal metaplastic epithelium. Polar/apolar compounds induced secretory activity, whereas retinoic acid was able to induce ciliogenesis in some cases. Therefore, the cuboidal metaplastic condition appears to be reversible, and two distinct pathways of differentiation, secretory and ciliogenetic, are identifiable.

Acetamides↗
PubMed1995

Dominant oncogenes, tumor suppressors, and radiosensitivity.

A variety of conflicting results appeared in the literature concerning the effect of dominant oncogenes on the sensitivity to irradiation and to anticancer agents in a number of cell lines of human and animal origin. In this report we provide evidence supporting the hypothesis that the tumor suppressor gene p53 and the apoptosis suppressor gene bcl2 modulate the effect of dominant oncogenes and that the effect of dominant oncogenes on resistance or sensitivity is dependent on the balance between the expression of p53 and bcl2.

Apoptosis↗
PubMed1995

Study of second messenger levels and of sugar catabolism enzyme activities in transformed cells resistant to ionizing radiations.

We measured the level of second messengers, the activity of carbohydrate metabolism enzymes, and the resistance to ionizing radiations in normal 32D hematopoietic cells, in v-erbB transformants and in spontaneous transformants. v-erbB and spontaneous transformants were resistant to radiations as compared with their normal counterpart. The second messenger diacylglycerol was elevated in radioresistant clones. Only v-erbB transformants showed increase of the activities of enolase and glucose-6-phosphate dehydrogenase. v-erbB-transformed NIH/3T3 cells, selected as control, showed identical correlation between radioresistance, increase of diacylglycerol, and of enolase and glucose-6-phosphate dehydrogenase activity. These results indicate that increase of diacylglycerol is correlated with resistance to the killing effect of ionizing radiations and could be proposed as a marker of radioresponse.

3T3 Cells↗
PubMed1994

Effect of phosphotyrosine phosphatase over-expression on glutathione metabolism in normal and oncogene-transformed cells.

We measured the level of reduced glutathione (GSH) and oxidized glutathione (GSSG) in normal and oncogene-transformed NIH/3T3 fibroblasts and 32D hematopoietic cells. NIH/3T3 cells transformed by the activated oncogenes erbB, src, and raf, showed increased levels of GSH with concomitant alterations in the levels of GSH-related enzymes. Transfection and over-expression of a synthetic gene coding for a phosphotyrosine protein phosphatase (PTPase), which inhibited the proliferation of normal and transformed NIH/3T3 cells, was accompanied by a decrease in GSH levels in normal and erbB-transformed fibroblasts, and by an increase in src and raf transformants. Among GSH-related enzymes, only gamma-glutamylcysteine synthetase was altered in normal and erbB-transformed NIH/3T3 fibroblasts following PTPase transfection. Therefore, tyrosine phosphorylation could be selectively involved in the regulation of GSH metabolism in normal and oncogene-transformed NIH/3T3 fibroblasts, possibly by a dual-type effect on receptor/oncoprotein-mediated mitogenic signal transduction. However, no relationship was observed between the GSH and PTPase effect on cell growth, either after oncogene transfection or PTPase transfection. Moreover, the changes in GSH metabolism were specifically related to cell lineage. In fact GSH and related enzymes did not change in 32D hematopoietic cells transformed by the same activated erbB oncogene and in those--normal or transformed--over-expressing the PTPase: in these cells also, over-expression of the PTPase gene was not accompanied by growth inhibition.

3T3 Cells↗
PubMed1994

Second messenger formation altered by different dialysis membranes in human leukocytes.

A number of agents stimulate transmembrane cell-signaling in different cell types through the formation of the second messenger diacylglycerol (DAG) which activates protein kinase C (PKC). The aim of this study was to investigate phospholipase C activation, DAG formation, and cellular adhesion to dialysis membranes after simulated dialytic treatment of either human leukocytes or clonal hematopoietic cells. Cells were circulated for 60 minutes in a closed-loop dialysis system using three different dialyzers: cuprophan (CU), polysulphone (PS), and AN69 (PAN). Another cell aliquot was left within the dialyzers without circulation. Samples were taken at different time intervals and cells counted. Cells were labeled with tritiated glycerol overnight, and DAG was measured by thin-layer chromatography. Our data showed that cells tended to adhere with more efficiency to CU than to the synthetic dialyzers. Circulation in the in vitro dialysis circuit resulted in the rapid (5 min) formation of [3H]DAG (CU 1.95-; PS 1.34-; PAN 1.24-fold increase over untreated cells). The DAG level peaked at 15 to 30 minutes and remained constant thereafter (CU 1.70; PS 1.96; PAN 1.66). When we measured DAG formation in cells that had been kept in the dialyzers without circulation, we found that cells exposed to CU showed a much higher and rapid activation than those exposed to PS or PAN, as if CU per se was able to activate early cell signaling (CU 1.95-; PS 0.97-; PAN 1.09-; DAG, -fold increase over control).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1994

Correction of neutropenia with rHuG-CSF after loss of response to rHuGM-CSF following autologous bone marrow transplant.

We describe a patient who presented with graft failure following autologous BMT, with an initial response of the neutrophil count to rHuGM-CSF but eventual loss of this response. Subsequently, this patient responded to rHuG-CSF. This could be explained by the fact that rHuG-CSF stimulates both early and late myeloid progenitor cells whereas rHuGM-CSF stimulates mainly the intermediate myeloid progenitor cells. This finding suggests that rHuG-CSF should be investigated for the treatment of patients with graft failure following ABMT.

Adolescent↗
PubMed1993

Negative growth control by a novel low M(r) phosphotyrosine protein phosphatase in normal and transformed cells.

Having determined the complete amino acid sequence of a cytosolic phosphatase purified from bovine liver, we studied the role of this enzyme (referred to as 'PTPase') in the control of cell proliferation. We used NIH/3T3 fibroblasts, both normal and transformed by the oncogenes v-erbB, v-src, and v-raf: a synthetic gene coding for PTPase was transfected into, and overexpressed in, normal and transformed NIH/3T3 cells with resulting inhibition of cell growth. Inhibition of proliferation correlated with the level of foreign PTPase; growth in soft agar was also inhibited in transformants overexpressing the enzyme. However, PTPase overexpression did not inhibit the rapid turnover of inositol lipids stimulated by platelet-derived growth factor. We conclude that this novel PTPase is active on cell type-specific signalling substrates that control normal and transformed fibroblast proliferation.

3T3 Cells↗
PubMed1993

Cytokine receptor signal transduction mechanisms in immuno-hematopoietic cells.

Novel aspects of cytokine receptor signal transduction are discussed and cytokine receptors classified based on ligand-dependent signalling. An introductory section presents an overview of the role of cytokines in hematopoiesis. A brief explanation of basic concepts, such as redundancy, pleiotropy, synergism, etc., important for the understanding of cell response to cytokines, is also included. Three of five classes of receptors show the involvement of tyrosine kinase activity as the key step in signal transduction. The importance of tyrosine phosphorylation in cellular response to cytokines is pointed out.

Animals↗
PubMed1993

Altered metabolism of glutathione in cells transformed by oncogenes which cause resistance to ionizing radiations.

We measured glutathione (GSH) metabolism in normal NIH/3T3 fibroblasts, and in cells transformed by the oncogenes sis, erbB, src, ras, dbl, and raf.erbB,src,ras and raf, but not sis and dbl transformants, showed increased level of total and reduced GSH as compared with normal NIH/3T3 fibroblasts; oxidized GSH was elevated only in src- and ras-transformed cells. Increased total GSH content was associated with decreased activity of the synthetic enzyme gamma-glutamylcysteine synthetase, and oxidized GSH level with increased activity of GSH reductase. These data suggest that GSH synthesis was selectively enhanced in cells transformed by specific oncogenes, with resulting down-regulation of its synthetic enzyme; alterations of GSH metabolism appeared to be peculiar of transformation by specific oncogenes, and not trivial epiphenomena of neoplastic transformation. Oncogenic transformants that presented elevated level of GSH were also those reported to be resistant to antineoplastic drugs and ionizing radiations, thus confirming a possible link between altered GSH metabolism and resistance to antineoplastic treatment.

3T3 Cells↗
PubMed1993

Urokinase-urokinase receptor interaction: non-mitogenic signal transduction in human epidermal cells.

We studied non-mitogenic signal transduction in a human cell line of epidermal origin which is induced to chemotaxis following stimulation with human urokinase-type plasminogen activator (u-PA) or with the amino-terminal fragment (ATF) of u-PA A chain, which specifically interacts with the cellular receptor. U-PA and ATF stimulated the formation of diacylglycerol (DAG) independently of inositol lipid and phosphatidylcholine turnover, but concomitantly with de novo synthesis from glucose, thus resembling the DAG neosynthesis activated by insulin. DAG was measured in normal epidermal cells and in cells transfected with the human u-PA receptor (u-PAR) gene and stimulated with u-PA or ATF. Transfected clones showed an increase of cell motility under an ATF gradient in vitro as well as an increase of DAG production. These findings identify a novel mechanism of second messenger formation that conveys chemotactic signals upon stimulation of the u-PAR.

Cell Line↗
PubMed1993

Antiproliferative effects of heparin on normal and transformed NIH/3T3 fibroblasts.

We studied the effect of heparin on proliferation and signalling in normal NIH/3T3 fibroblasts, and in cells transformed by different oncogenes. Heparin inhibited the proliferation of normal as well as of v-sis and v-erbB transformed fibroblasts in the presence of serum, but failed to inhibit v-erbB-driven proliferation in serum-starved cultures; under these conditions, heparin inhibited by approximately 50% the proliferation of normal and v-sis- transformed cells. Heparin also inhibited PDGF-induced cell proliferation and inositol lipid turnover in v-sis transformants, but it did not affect PDGF mitogenic signalling in NIH/3T3 fibroblasts.

3T3 Cells↗
PubMed1993

Defective signal transduction in platelets from cirrhotics is associated with increased cyclic nucleotides.

BACKGROUND: Patients with advanced cirrhosis show defective platelet aggregation, which is dependent, at least in part, on intrinsic platelet abnormalities. The aim of this study was to evaluate the activating and inhibitory pathways of platelet signal transduction in cirrhotic patients. METHODS: Twelve cirrhotic patients and 12 control subjects participated in this study. Measurements were performed on washed platelets. RESULTS: Thrombin-stimulated inositol 1,4,5-trisphosphate production was reduced fivefold, and the increase in cytosolic calcium concentration was significantly lower in platelets from cirrhotic patients following stimulation with thrombin, platelet activating factor, or U-46619. In addition, the activity of the platelet Na+/H+ antiporter, evaluated after an acid load, was significantly lower in platelets from cirrhotic patients (0.90 +/- 0.19 vs. 1.37 +/- 0.16 delta pHi/min, P = 0.07). Cirrhotic patients also showed a significantly increased basal intraplatelet content of both 5'-cyclic adenosine monophosphate (cAMP) (2724 +/- 330 vs. 1561 +/- 258 fmol/10(8) platelets, P < 0.05) and 5'-cyclic guanosine monophosphate (cGMP) (217 +/- 18 vs. 159 +/- 29 fmol/10(8) platelets, P < 0.05). CONCLUSIONS: Our results indicate that in platelets from cirrhotic patients, defective early signal transduction is associated with an increase in platelet cAMP and cGMP, thus revealing new mechanisms contributing to the defective platelet function in this disease.

Adult↗
PubMed1992

Overexpression of a synthetic phosphotyrosine protein phosphatase gene inhibits normal and transformed cell growth.

We studied the level of the cytosolic phosphotyrosine protein phosphatase (PTPase) (originally termed low-M(r) acid phosphatase) in normal NIH/3T3 and in v-erbB-transformed fibroblasts. The level of the enzyme, assayed by ELISA, was inversely related to cell proliferation, normally growing cells had less enzyme than their contact-inhibited counterparts and v-erbB transformants had less enzyme than normal NIH/3T3. In order to overexpress the enzyme and study its effects in normal and transformed cells, we transfected a synthetic gene coding for the PTPase in control NIH/3T3 and v-erbB transformants. The overexpressed enzyme was recognized by antibodies raised against the native enzyme and, in cells overexpressing the PTPase, we observed a marked dephosphorylation of tyrosyl residues of cellular proteins. Cell proliferation, in both normal and v-erbB transformants overexpressing the PTPase, was measured. We observed that PTPase overexpression was accompanied by significantly reduced thymidine incorporation in both cell types, either serum-starved or serum-stimulated. The ability of transformed v-erbB cells to grow in soft agar was also markedly decreased by overexpression of the enzyme. Taken together, our results indicate that overexpression of PTPase might interfere with mitogenic signalling pathways in both normal and transformed cells, and propose a role for PTPase in the control of cell proliferation.

3T3 Cells↗
PubMed1992

Mitogenic signal transduction: a common target for oncogenes that induce resistance to ionizing radiations.

We hypothesized that resistance to ionizing radiations accompanying neoplastic transformation caused by some oncogenes was due to common biochemical pathways affecting the mechanism of mitogenic signal transduction. In order to verify this hypothesis, we studied the formation of mitogenic second messengers in cells transformed by oncogenes that induce radioresistance. We observed an increase of diacylglycerol which activates protein kinase C, an increase of phosphatidylcholine metabolism, with a concomitant decrease of inositol lipid metabolism. Our data show that sensitivity to ionizing radiations was inversely related to the intracellular level of diacylglycerol; study of signalling alterations in spontaneous tumors could provide predictive indications about the responsiveness of neoplasia to radiation therapy.

3T3 Cells↗
PubMed1991

Mitogenic signal transduction in normal and transformed 32D hematopoietic cells.

We studied mitogenic signal transduction in normal and oncogene-transformed 32D cells, a murine hematopoietic cell line that is normally dependent on interleukin-3 (IL3) for proliferation and survival. The formation of second messengers was measured in normal cells stimulated with IL3, and in cells transfected with foreign growth factor receptor genes and stimulated with appropriate growth factors. We also measured the steady-state level of second messengers in 32D cells transformed by erbB, abl, and src oncogenes which abrogate growth factor requirement. We found that IL3 stimulated the formation of diacylglycerol independently of inositol lipid turnover, but concomitantly with increased turnover of phosphatidylcholine. Epidermal growth factor (EGF), and platelet-derived growth factor (PDGF) stimulated the 'classical' turnover of inositol lipids with formation of diacylglycerol and calcium-mobilizing inositol phosphates. Colony stimulating factor-1 triggered inositol lipid turnover, although to a much lower extent than EGF and PDGF. Transformed cells showed elevated levels of diacylglycerol together with increased turnover of phosphoinositides and phosphatidylcholine. Taken together these results indicate that different growth factors and oncoproteins associate with multiple signalling pathways in 32D cells.

Animals↗
PubMed1991

Heparin inhibits A431 cell growth independently of serum and EGF mitogenic signalling.

In several cell types heparin exerts an antiproliferative action; here we report that heparin inhibited the growth of human epidermoid carcinoma A431 cells. Heparin binding to the cell surface was necessary for growth inhibition; binding was influenced by the molecular weight of heparin. Inhibition of A431 cell proliferation was evident in the presence and in the absence of serum, thus indicating that heparin did not act by binding and 'subtracting' nutrients or other serum factors. In confluent A431 cells, EGF induced DNA synthesis, but heparin did not inhibit this effect; consistently, it did not affect inositol lipid turnover triggered by EGF or bradykinin.

Bradykinin↗
PubMed1991

Calpastatin level in spontaneously hypertensive rats.

We studied calpastatin activity in erythrocytes of Milan hypertensive and prehypertensive rats, in their normotensive controls, in F1 and F2 hybrids, and in two inbred strains derived from F2, one hypertensive and the other normotensive. Our results show that the decrease in calpastatin activity observed in Milan hypertensive rats was not caused by hypertension, it was transmitted in a recessive way in heterozygous, and it was not correlated to hypertension.

Animals↗