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Abstract
The induction of stress proteins was studied in two human and two murine melanoma cell lines. Exposure for 1 h to heat (42 °C), to ethanol (6%), to arsenate (100 μM) and to disulfiram (50 μM) induced the expression of SPs with apparent molecular weights of 100, 86, 70-72 and 24-26 Kd. Quantitation of the single SPs indicated that the basal level as well as the enhanced synthesis following the various stressors were different in each cell line. The induction of the 100 Kd species occurred in only one murine melanoma and not in the others. The 86 and in particular the 70-72 Kd species were the most prominent groups, whereas the 24-26 SPs were induced only following arsenate and disulfiram exposure in the three melanoma cell lines. In one of the murine melanomas, the expression of SPs was markedly reduced compared to the other cell lines. No definite specific patterns of SP expression could be identified in tumors of the same histologic type.
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2
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Mileo AM, Fanuele M, Battaglia F, Scambia G, Benedetti-Panici C, Mattei E, Mancuso S, Delpino A. Preliminary evaluation of HER-2/neu oncogene and epidermal growth factor receptor expression in normal and neoplastic human ovaries. Int J Biol Markers 2018; 7:114-8. [PMID: 1634822 DOI: 10.1177/172460089200700208] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The HER-2/neu oncogene (a member of the Erb-like oncogene family) is distinct from but closely related to the c-erb B gene which encodes the epidermal growth factor receptor (EGFr). HER-2/neu gene amplification was found in a large number of mammary carcinomas and there was a strong correlation between this phenomenon and poor prognosis. In our study HER-2/neu oncogene expression was determined in 16 malignant ovarian tumors, 2 ovarian lymphomas and 5 normal ovaries. The HER-2/neu gene was found both in normal ovaries and malignant tumors, without any apparent difference among the various histological types. In all the specimens examined, HER-2/neu expression did not seem to be related to EGF binding capacity.
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Affiliation(s)
- A M Mileo
- Regina Elena Institute for Cancer Research, Roma, Italy
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3
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Amato R, Scumaci D, D'Antona L, Iuliano R, Menniti M, Di Sanzo M, Faniello MC, Colao E, Malatesta P, Zingone A, Agosti V, Costanzo FS, Mileo AM, Paggi MG, Lang F, Cuda G, Lavia P, Perrotti N. Sgk1 enhances RANBP1 transcript levels and decreases taxol sensitivity in RKO colon carcinoma cells. Oncogene 2012; 32:4572-8. [PMID: 23108393 DOI: 10.1038/onc.2012.470] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 08/01/2012] [Accepted: 08/21/2012] [Indexed: 12/16/2022]
Abstract
The serum- and glucocorticoid-regulated kinase (Sgk1) is essential for hormonal regulation of epithelial sodium channel-mediated sodium transport and is involved in the transduction of growth factor-dependent cell survival and proliferation signals. Growing evidence now points to Sgk1 as a key element in the development and/or progression of human cancer. To gain insight into the mechanisms through which Sgk1 regulates cell proliferation, we adopted a proteomic approach to identify up- or downregulated proteins after Sgk1-specific RNA silencing. Among several proteins, the abundance of which was found to be up- or downregulated upon Sgk1 silencing, we focused our attention of RAN-binding protein 1 (RANBP1), a major effector of the GTPase RAN. We report that Sgk1-dependent regulation of RANBP1 has functional consequences on both mitotic microtubule activity and taxol sensitivity of cancer cells.
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Affiliation(s)
- R Amato
- Department of Human Health, University Magna Graecia at Catanzaro, Campus S Venuta, Località Germaneto Viale Europa, Catanzaro, Italy
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4
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Abstract
RB, the most investigated tumor suppressor gene, is the founder of the RB family of growth/tumor suppressors, which comprises also p107 (RBL1) and Rb2/p130 (RBL2). The protein products of these genes, pRb, p107 and pRb2/p130, respectively, are also known as 'pocket proteins', because they share a 'pocket' domain responsible for most of the functional interactions characterizing the activity of this family of cellular factors. The interest in these genes and proteins springs essentially from their ability to regulate negatively cell cycle processes and for their ability to slow down or abrogate neoplastic growth. The pocket domain of the RB family proteins is dramatically hampered in its functions by the interference of a number of proteins produced by the small DNA viruses. In the last two decades, the 'viral hypothesis' of cancer has received a considerable renewed impulse from the notion that small DNA viruses, such as Adenovirus, Human papillomavirus (HPV) and Polyomavirus, produce factors that can physically interact with major cellular regulators and alter their function. These viral proteins (oncoproteins) act as multifaceted molecular devices that have evolved to perform very specific tasks. Owing to these features, viral oncoproteins have been widely employed as invaluable experimental tools for the identification of several key families of regulators, particularly of the cell cycle homeostasis. Adenovirus early-region 1A (E1A) is the most widely investigated small DNA tumor virus oncoprotein, but relevant interest in human oncology is raised by the E1A-related E7 protein from transforming HPV strains and by Polyomavirus oncoproteins, particularly large and small T antigens from Simian virus 40, JC virus and BK virus.
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Affiliation(s)
- A Felsani
- Istituto di Neurobiologia e Medicina Molecolare, CNR, Rome, Italy
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5
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Abstract
Nm23-NDPKs besides contributing to the maintenance of the cellular nucleoside triphosphate pool, exert regulatory properties in a variety of cellular events including proliferation, invasiveness, development, differentiation, and gene regulation. This review focuses on recently discovered protein-protein interactions involving the Nm23 proteins. The findings herein summarized provide new and intriguing suggestions for a more extensive understanding of the biological functions of the Nm23 proteins.
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Affiliation(s)
- D Lombardi
- Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy.
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6
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Abstract
Nm23-NDPKs besides contributing to the maintenance of the cellular nucleoside triphosphate pool, exert regulatory properties in a variety of cellular events including proliferation, invasiveness, development, differentiation, and gene regulation. This review focuses on recently discovered protein-protein interactions involving the Nm23 proteins. The findings herein summarized provide new and intriguing suggestions for a more extensive understanding of the biological functions of the Nm23 proteins.
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Affiliation(s)
- D Lombardi
- Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy.
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7
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Sang N, Severino A, Russo P, Baldi A, Giordano A, Mileo AM, Paggi MG, De Luca A. RACK1 interacts with E1A and rescues E1A-induced yeast growth inhibition and mammalian cell apoptosis. J Biol Chem 2001; 276:27026-33. [PMID: 11358958 DOI: 10.1074/jbc.m010346200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The adenoviral E1A proteins are able to promote proliferation and transformation, inhibit differentiation, induce apoptosis, and suppress tumor growth. The extreme N terminus and conserved region one of E1A, which are indispensable for transcriptional regulation and for binding to p300/CBP, TBP, and pCAF, play essential roles in these abilities. These observations strongly suggest an intrinsic link between E1A-mediated transcriptional regulation and other effects. In this report, we show that E1A inhibits the normal growth of Saccharomyces cerevisiae HF7c, and this inhibition also depends on the domains required for transcriptional regulation. We demonstrate that E1A associates with histone acetyltransferase activity and represses the transactivation activity of transcription factor in S. cerevisiae, suggesting that E1A may suppress the expression of genes required for normal growth. Based on yeast growth rescue, we present a genetic screening strategy that identified RACK1 as an E1A antagonizing factor. Expression of human RACK1 efficiently relieves E1A-mediated growth inhibition in HF7c and protects human tumor cells from E1A-induced apoptosis. Finally, we show that RACK1 decreases E1A-associated histone acetyltransferase activity in yeast and mammalian cells, and physically interacts with E1A. Our data demonstrate that RACK1 is a repressor of E1A, possibly by antagonizing the effects of E1A on host gene transcription.
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Affiliation(s)
- N Sang
- Cardeza Foundation, Department of Medicine, Jefferson Medical College, Philadelphia, Pennsylvania 19107, USA
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8
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Fucile S, Palma E, Mileo AM, Miledi R, Eusebi F. Human neuronal threonine-for-leucine-248 7 mutant nicotinic acetylcholine receptors are highly Ca2+ permeable. Proc Natl Acad Sci U S A 2000; 97:3643-8. [PMID: 10716716 PMCID: PMC16293 DOI: 10.1073/pnas.97.7.3643] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A cDNA coding for the human neuronal nicotinic alpha7 receptor subunit with Leu-248 mutated to threonine was expressed in Xenopus oocytes. When activated by acetylcholine (AcCho), the receptors expressed generated currents that had low desensitization, linear current-voltage relation, and high apparent affinity for both AcCho and nicotine. These characteristics are similar to those already described for the chick threonine-for-leucine-247 alpha7 nicotinic AcCho receptor (nAcChoR) mutant (L247Talpha7). These properties were all substantially maintained when the human L248Talpha7 mutant was transiently expressed in human Bosc 23 cells. Simultaneous whole-cell clamp and fluorescence measurements with the Ca(2+) indicator dye Fura-2 showed that nicotine induced a Ca(2+) influx in standard 2 mM Ca(2+) solution. The average fractional Ca(2+) current flowing through L248Talpha7 nAcChoRs was 6.7%, which is larger than that flowing through muscle alpha(beta)epsilon(delta) nAcChoRs (4.1%). The relative Ca(2+) permeability, determined in oocytes in the absence of Cl(-), was measured from the shift in reversal potential caused by increasing the external Ca(2+) concentration from 1 to 10 mM. The human wild-type alpha7 nAcChoR was found to be more permeable than the L248Talpha7 mutant to Ca(2+). Our findings indicate that the Ca(2+) permeability of the homomeric alpha7 nAcChoR is larger than that of the heteromeric neuronal nicotinic receptors studied to date and is possibly similar to that of the N-methyl-D-aspartate subtype of brain glutamate receptors.
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Affiliation(s)
- S Fucile
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Medicina Sperimentale e Patologia, Universita' di Roma "La Sapienza, " Viale Regina Elena 324, I00161 Roma, Italy
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9
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Limatola C, Mileo AM, Giovannelli A, Vacca F, Ciotti MT, Mercanti D, Santoni A, Eusebi F. The growth-related gene product beta induces sphingomyelin hydrolysis and activation of c-Jun N-terminal kinase in rat cerebellar granule neurones. J Biol Chem 1999; 274:36537-43. [PMID: 10593952 DOI: 10.1074/jbc.274.51.36537] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The growth-related gene product beta (GRObeta) is a small chemoattractant cytokine that belongs to the CXC chemokine family, and GRObeta receptors are expressed in the brain, including the cerebellum. We demonstrate that rat cerebellar granule neurones express the GRObeta receptor CXCR2. We also show that, in addition to the known stimulation of a phosphoinositide-specific phospholipase C, GRObeta activates both neutral (N-) and acidic (A-) sphingomyelinases (SMase) and the stress-activated c-Jun N-terminal kinase 1 (JNK1). Although both exogenous ceramide and bacterial SMase stimulate JNK1, GRObeta-induced JNK1 activation is an event probably independent of ceramide generated by A-SMase, since it is maintained in the presence of compounds that block A-SMase activity. This is the first report on the activation of the SMase pathway by chemokines.
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Affiliation(s)
- C Limatola
- Dipartimento di Medicina Sperimentale e Patologia, Universita' di Roma La Sapienza, Roma, Italy.
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10
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Giovannelli A, Limatola C, Ragozzino D, Mileo AM, Ruggieri A, Ciotti MT, Mercanti D, Santoni A, Eusebi F. CXC chemokines interleukin-8 (IL-8) and growth-related gene product alpha (GROalpha) modulate Purkinje neuron activity in mouse cerebellum. J Neuroimmunol 1998; 92:122-32. [PMID: 9916887 DOI: 10.1016/s0165-5728(98)00192-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We give here evidence that Purkinje neurons (PNs) of mouse cerebellar slices studied with patch clamp technique combined with laser confocal microscopy, respond to human IL-8 and GROalpha by (i) a cytosolic Ca2+ transient compatible with inositol (1,4,5) trisphosphate (InsP3) formation; (ii) an enhancement of the neurotransmitter release; and (iii) an impairment of the long-term depression of synaptic strength (LTD). It was also found the expression of IL-8 receptor type 2 in PN and granule cells by immunofluorescence, immunoblotting and RT-PCR analysis. Considered together these findings suggest that IL-8 and GROalpha may play a neuromodulatory role on mouse cerebellum.
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Affiliation(s)
- A Giovannelli
- Dipartimento di Medicina Sperimentale Università di L'Aquila, Rome, Italy
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11
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Abstract
We report here that, in cultured cerebellar granule cells, the CXC chemokine GRObeta stimulates the signaling pathway of the extracellular signal-regulated kinases, and enhances both evoked and spontaneous postsynaptic currents in patch clamped Purkinje neurons from rat cerebellar slices. The GRObeta-induced enhancement of the excitatory post-synaptic currents evoked by stimulating the parallel fibres is blocked by the inhibitor of the extracellular signal-regulated kinases pathway PD98059, which also reduces both basal frequency of spontaneous post-synaptic currents and mean amplitude of evoked excitatory post-synaptic currents. Our results suggest that GRObeta modulates neurotransmitter release in the cerebellum through the activation of the extracellular signal-regulated kinases pathway.
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Affiliation(s)
- D Ragozzino
- Dipartimento di Medicina Sperimentale e Patologia Università di Roma La Sapienza, Italy
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12
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Abstract
1. We performed an RNase protection assay on cultured C2C12 mouse myotubes, demonstrating that the gamma subunit of the fetal muscle acetylcholine receptor (AChR) exists as two splice variants, which differ in the presence of the amino terminal exon 5. 2. We studied unitary ACh-evoked events in fibres acutely dissociated from the hindlimb flexor digitorum brevis muscle of BALB/C mice aged between embryonic day 16 (E16) and postnatal day 6 (P6). 3. At all ages, the channel conductance was about 30 pS, typical of the fetal form of the AChR. The mean open time increased significantly from 6 ms at E16 to 9 ms at E19, then decreased to about 5 ms during the first postnatal week. The lengthening of the open time was considerably delayed in hypothyroid mice. Data were recorded at 24-26 degrees C. 4. On the basis of previously reported experiments in heterologous expression systems, we suggest that the modulation of channel open time is related to the expression of the AChR incorporating the gammas subunit. These events might be coupled to the crucial modifications in muscle innervation that take place during the same developmental period.
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Affiliation(s)
- F Grassi
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Medicina Sperimentale e Patologia, Università di Roma, Roma, Italy.
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13
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Fucile S, Barabino B, Palma E, Grassi F, Limatola C, Mileo AM, Alemà S, Ballivet M, Eusebi F. Alpha 5 subunit forms functional alpha 3 beta 4 alpha 5 nAChRs in transfected human cells. Neuroreport 1997; 8:2433-6. [PMID: 9261804 DOI: 10.1097/00001756-199707280-00005] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
nAChRs heterologously expressed in human cells after transient transfection with alpha 3 beta 4 alpha 5 or alpha 3 beta 4 subunit cDNAs exhibited similar sensitivities to antagonists and comparable functional channel profiles. However, the sum of two Hill equations was required for best fitting the ACh dose-current response curves after co-expression of alpha 5, alpha 3 and beta 4 subunits. One component was comparable to that obtained in alpha 3 beta 4-transfected cells, while the additional component, putatively attributed to an alpha 3 beta 4 alpha 5 nAChR population, showed a Hill coefficient > 2 and a nine-fold greater half-maximal ACh concentration (EC50). These results suggest that the alpha 5 subunit participates in the assembly of alpha 3 beta 4 alpha 5 nAChRs complexes in human cells, adding a new member to the family of neuronal nicotinic receptors.
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Affiliation(s)
- S Fucile
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Medicina Sperimentale e Patologia, Università di Roma, Italy
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14
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Ragozzino D, Fucile S, Giovannelli A, Grassi F, Mileo AM, Ballivet M, Alemà S, Eusebi F. Functional properties of neuronal nicotinic acetylcholine receptor channels expressed in transfected human cells. Eur J Neurosci 1997; 9:480-8. [PMID: 9104590 DOI: 10.1111/j.1460-9568.1997.tb01625.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To study how subunit composition affects the functional properties of neuronal nicotinic acetylcholine receptors (nAChRs), we examined the behaviour of acetylcholine (ACh)-induced single-channel currents in human BOSC 23 cells transiently transfected with various subunit cDNA combinations. For all nAChRs examined (chick and rat alpha 3 beta 4, chick alpha 3 beta 2, alpha 4 beta 2, alpha 7 and alpha 8), expression levels were high enough to allow measurements of acetylcholine-evoked whole-cell currents and nicotine-elicited Ca2+ transients as well as the functional characterization of nAChR channels. Unitary acetylcholine-evoked events of alpha 8 nAChR had a slope conductance of 23 pS, whereas two conductance classes (19-23 and 32-45 pS) were identified for all other nAChR channels. The mean channel open times were significantly longer for homomeric alpha 7 and alpha 8 nAChRs (6-7 ms) than for heteromeric nAChRs (1-3 ms), with the exception of alpha 3 beta 4 nAChRs (8.4 ms for rat, 7 ms for chick). At least two species of heterologously expressed nAChRs (alpha 3 beta 4 and alpha 3 beta 2) exhibited single-channel characteristics similar to those reported for native receptors. The variety of nAChR channel conductance and kinetic properties encountered in human cells transfected with nAChR subunits contributes to the functional diversity of nAChRs in nerve cells.
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Affiliation(s)
- D Ragozzino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Medicina Sperimentale e Patologia, Università di Roma, Italy
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15
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Limatola C, Palma E, Mileo AM, Eusebi F. Phorbol ester modulation of both delta-mutant and subunit-omitted nicotinic receptors expressed in Xenopus oocytes. Brain Res 1996; 742:172-6. [PMID: 9117392 DOI: 10.1016/s0006-8993(96)00961-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The action of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), the potent stimulator of protein kinase C (PKC), on acetylcholine-activated currents (I(Ach)) was investigated in voltage clamped Xenopus laevis oocytes injected with RNAs encoding murine embryonic nicotinic acetylcholine receptor (AChR) subunits. Comparable potentiation and acceleration of decay of I(ACh) were observed within minutes of phorbol ester application in oocytes injected with various RNA subunit combinations: (i) alpha beta gamma delta; (ii) alpha beta gamma; (iii) alpha beta delta; and (iv) alpha beta gamma delta(AAA), a mutant of the delta subunit with serine residues 360-361-362 mutated to alanine. Our findings indicate that the effects on I(ACh) induced by PKC stimulation are independent of both gamma and delta subunits and, accordingly, of the presence of PKC phosphorylation sites on delta subunit. It is here suggested a novel PKC-dependent modulatory mechanism of cholinergic receptor which does not involve direct phosphorylation of the AChR and requires phosphorylation of intermediate regulatory protein(s).
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Affiliation(s)
- C Limatola
- Laboratorio di Biofisica, Centro Ricerca Sperimentale, Istituto Regina Elena, Roma, Italy
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16
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Fucile S, Mileo AM, Grassi F, Salvatore AM, Alemà S, Eusebi F. Identification of a determinant of acetylcholine receptor gating kinetics in the extracellular portion of the gamma subunit. Eur J Neurosci 1996; 8:2564-70. [PMID: 8996805 DOI: 10.1111/j.1460-9568.1996.tb01550.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A large body of structure-function studies has identified many of the functional motifs underlying ion permeation through acetylcholine receptor (AChR) channels. The structural basis of channel gating kinetics is, however, incompletely understood. We have previously identified a novel shorter form of the AChR gamma subunit, which lacks the 52 amino acids within the extracellular amino-terminal half, encoded by exon 5. To define the contribution of the missing domain to AChR channel function, we have transiently coexpressed the mouse short gamma subunit [gamma(s)] with alpha, beta and delta subunits in human cells and recorded single-channel currents from the resulting AChRs. Our findings show that replacement of the gamma by the gamma(s) subunit confers a long duration characteristic to AChR channel openings without altering unitary conductance sizes or receptor affinity for the transmitter. We also show that alpha beta gamma(s) delta AChR channels exhibit a peculiar voltage sensitivity characterized by a short opening duration when the membrane potential is hyperpolarized. Together, these findings indicate that the domain in the extracellular amino-terminal half of the gamma subunit that encompasses a conserved disulphide loop and a critical tyrosine residue implicated in receptor oligomerization and insertion at the cell surface is a functional motif that also modulates AChR channel gating kinetics. The results also provide a molecular explanation of the functional diversity exhibited by skeletal muscle AChRs during development.
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Affiliation(s)
- S Fucile
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Medicina Sperimentale e Patologia, Università di Roma, Italy
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17
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Palma E, Mileo AM, Eusebi F, Miledi R. Threonine-for-leucine mutation within domain M2 of the neuronal alpha(7) nicotinic receptor converts 5-hydroxytryptamine from antagonist to agonist. Proc Natl Acad Sci U S A 1996; 93:11231-5. [PMID: 8855338 PMCID: PMC38313 DOI: 10.1073/pnas.93.20.11231] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A study was made of the effects of 5-hydroxytryptamine (5HT) on homomeric neuronal nicotinic receptors (nAcChoR) expressed in Xenopus oocytes after injection of cDNA encoding the wild-type chicken alpha(7) subunit. Acetylcholine (AcCho) elicited large currents (IAcCho) that were reduced by 5HT in a reversible and dose-dependent manner, with a half-inhibitory concentration (IC50) of 56 microM and a Hill coefficient (nH) of 1.2. The inhibition of IAcCho by 5HT was noncompetitive and voltage independent, a behavior incompatible with a channel blockade mechanism. 5HT alone did not elicit membrane currents in oocytes injected with the wild-type alpha(7) subunit cDNA. In contrast, 5HT elicited membrane currents (I5HT) in oocytes injected with cDNA encoding an alpha(7) mutant subunit with a threonine-for-leucine-247 substitution (L247T alpha(7)). I5HT was inhibited by the potent nicotinic receptor blockers alpha-bungarotoxin (100 nM) and methyllycaconitine (1 microM). Furthermore, the characteristics of I5HT, including its voltage dependence, were similar to those of IAcCho. The 5HT dose-I5HT response gave an apparent dissociation constant EC50 of 23.5 microM and a Hill coefficient nH of 1.7, which were not modified by the presence of AcCho. Similarly, the apparent affinity of L247T alpha(7) for AcCho as well as its cooperativity were not influenced by 5HT, indicating a lack of mutual interactions between 5HT and AcCho. These results show that 5HT is a potent noncompetitive antagonist of neuronal alpha(7) nAcChoR, but it becomes a noncompetitive agonist following mutation of the highly conserved leucine residue 247 located in the channel domain M2.
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Affiliation(s)
- E Palma
- Istituto Pasteur-Fondazione Cenci Bolognetti, Rome, Italy
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18
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Delpino A, Mileo AM, Lapenta V, Piselli P, Verdina A, Polenzani L. Characterization of a new high-temperature-induced 66-kDa heat-shock protein, antigenically related to heat-shock protein 72. J Cell Biochem 1996; 63:51-60. [PMID: 8891903 DOI: 10.1002/(sici)1097-4644(199610)63:1<51::aid-jcb4>3.0.co;2-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
M-14 human melanoma cells, following severe hyperthermic exposures, synthesized a heat-shock protein of 66 kDa (hsp 66), in addition to the major "classic" heat-shock proteins. This hsp 66 was not expressed following mild hyperthermic exposures sufficient to trigger the synthesis of the other heat-shock proteins. The induction of hsp 66 was observed also in Li human glioma cells treated at 45 degrees C for 20 min. By contrast, hsp 66 was not induced in seven other human cell lines (both melanoma and nonmelanoma) when they were subjected to the same hyperthermic treatment. Immunological recognition experiments showed that hsp 66 cross-reacted with the inducible hsp 72, but not with the constitutive hsp 73. The possibility that hsp 66 is a breakdown product of hsp 72 was ruled out by the fact that Poly(A)+ RNA extracted from cells treated at 45 degrees C for 20 min was able to direct the synthesis of hsp 66 (together with hsp 72) in a message-dependent rabbit reticulocyte lysate, as well as in microinjected Xenopus oocytes. By contrast, only the hsp 72 was expressed using Poly(A)+ RNA extracted from cells heated at 42 degrees C for 1 h. Affinity chromatography experiments on ATP-agarose showed that hsp 66 did not bind ATP in vitro. hsp 66 was localized both in the cytoplasm (cytosol, mitochondria, and microsome fraction) and in the nuclei of cells recovered from a severe heat shock: this intracellular distribution closely corresponded to that of hsp 72. The nuclear-associated hsp 66 was found to be tightly bound to nuclear structures and could not be extracted by incubation in ATP-containing buffer.
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Affiliation(s)
- A Delpino
- Laboratory of Biophysics, Regina Elena Institute for Cancer Research, Rome, Italy
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19
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Grassi F, Palma E, Mileo AM, Eusebi F. The desensitization of the embryonic mouse muscle acetylcholine receptor depends on the cellular environment. Pflugers Arch 1995; 430:787-94. [PMID: 7478934 DOI: 10.1007/bf00386177] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The rate of desensitization of nicotinic acetylcholine (ACh) receptor (nAChR), an important characteristic of nAChR function, was studied in myotubes of the mouse C2C12 cell line at different times after fusion, by measuring the decay of ACh-evoked currents (IACh) under various patch-clamp configurations. We observed a progressive slowing of IACh decay rate (half-decay time rose from about 0.5 s to over 5 s) in myotubes of increasing size (i.e. age) under all experimental conditions, except in outside-out patches, when IACh decayed as fast as in the smallest myotubes. Single-channel conductance (about 35 pS) and open time (about 3.5 ms), measured in outside-out and cell-attached patches, were independent of myotube size. In Xenopus oocytes injected with poly(A+)RNA extracted from C2C12 myoblasts or mature myotubes, IACh decay was about 50 times slower than in myotubes. Neither cAMP-dependent nor diacylglycerol-dependent protein kinases, actin nor microtubule polymerization state influenced IACh decay. Our data indicate that the cellular environment, but not readily dialysable cytosolic factors, markedly influences the functional behaviour of nAChR.
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Affiliation(s)
- F Grassi
- Laboratorio di Biofisica, Centro Ricerca Sperimentale I.R.E., Via delle Messi d’ Oro 156, I-00158 Rome, Italy
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20
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Mileo AM, Palma E, Polenzani L, Limatola C, Grassi F, Eusebi F. Protein kinase C modulates exogenous acetylcholine current in Xenopus oocytes. J Neurosci Res 1995; 41:443-51. [PMID: 7473875 DOI: 10.1002/jnr.490410403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The modulation of acetylcholine-activated current (IACh) by protein kinase C (PKC) was studied in Xenopus laevis oocytes microinjected with either mRNA extracted from C2C12 myotubes (C2C12 mRNA) or RNAs encoding murine alpha beta gamma delta subunits of the nicotinic ACh receptor (nAChR). Voltage-clamped oocytes were treated for 90 sec with 12-O-tetradecanoylphorbol-13-acetate (TPA, 300 nM), a potent PKC activator. Transient increase in the amplitude and acceleration in the decay of IACh were invariably observed within minutes of TPA application, and were independent of extracellular Ca2+ concentration. Both parameters recovered to control within 20-30 min; then a slight depression of IACh developed. By this time, an initial PKC down regulation was observed. At the peak of TPA-induced potentiation, dose-response relations suggested an increased binding affinity of nAChR for the neurotransmitter. 4 alpha-phorbol 12,13-didecanoate (300 nM), a biologically inactive analogue of TPA, did not affect IACh, while staurosporine (5-10 microM), a potent inhibitor of PKC activity, suppressed the action of TPA on IACh. In oocytes co-injected with C2C12 mRNA and with rat brain mRNA, IACh was potentiated by 5-hydroxy-tryptamine (10 microM), whose receptors are coupled to phosphoinositide hydrolysis. The nAChR-channel activity in cell-attached patches increased when TPA was applied to the oocytes. In 50% of the oocytes examined, a sustained depression of the single channel activity followed. We conclude that in Xenopus oocytes an endogenous PKC system regulates the function of embryonic-type muscle nAChRs.
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Affiliation(s)
- A M Mileo
- Laboratory of Biophysics, Experimental Research Center, Rome, Italy
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21
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Abstract
Nicotinic acetylcholine receptors (nAcChoRs) of skeletal muscle are heterosubunit ligand-gated channels that mediate signal transmission from motor nerves to muscle. While cloning murine nAcChoR subunits, to gain an insight into the receptor diversity across species, we detected two forms of gamma subunits in the myogenic C2C12 cell line. Both forms are functional when expressed in Xenopus oocytes. One gamma subunit [long gamma (gamma 1)] was almost identical to that previously cloned in the murine BC3H-1 tumor cell line. The second form of gamma subunit [short gamma (gamma s)] lacked 156 bp (52 amino acids) in the extracellular N terminus, adjoining the hydrophobic segment M1, which corresponds to the fifth exon of the gamma-subunit gene. The two forms of gamma subunit coexist during myogenesis in vitro and in 17-day embryonic and denervated adult muscle fibers in vivo. However, the gamma s variant was the only form of gamma subunit in newborn muscle. In dissociated muscle fibers of newborn mice, AcCho-evoked channel openings were more prolonged when compared with C2C12 myotubes or denervated adult muscle fibers. The gamma s subunit may, thus, contribute to the structural and functional diversity of nAcChoRs in muscle cells.
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MESH Headings
- Acetylcholine/pharmacology
- Alternative Splicing
- Amino Acid Sequence
- Animals
- Base Sequence
- Cell Line
- DNA Primers
- Embryo, Mammalian
- Embryo, Nonmammalian
- Exons
- Female
- Gene Expression
- Macromolecular Substances
- Membrane Potentials/drug effects
- Mice
- Molecular Sequence Data
- Muscle, Skeletal/cytology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Oocytes/drug effects
- Oocytes/physiology
- Patch-Clamp Techniques
- Polymerase Chain Reaction
- Protein Conformation
- RNA, Messenger/isolation & purification
- RNA, Messenger/metabolism
- Receptors, Muscarinic/biosynthesis
- Receptors, Muscarinic/chemistry
- Transcription, Genetic
- Xenopus laevis
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Affiliation(s)
- A M Mileo
- Laboratorio di Biofisica, Centro Ricerca Sperimentale, IRE, Rome, Italy
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22
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Grassi F, Mileo AM, Monaco L, Punturieri A, Santoni A, Eusebi F. TNF-alpha increases the frequency of spontaneous miniature synaptic currents in cultured rat hippocampal neurons. Brain Res 1994; 659:226-30. [PMID: 7820666 DOI: 10.1016/0006-8993(94)90883-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) is a cytokine secreted by activated astrocytes and is known to alter evoked synaptic activity in slices of adult rat hippocampus. In this paper we show that TNF-alpha increases the frequency of spontaneous miniature synaptic currents in cultured hippocampal neurons, acting at nanomolar concentrations. In addition, we show that the mRNA for the 55 kDa TNF-alpha receptor (TNF-R1) is detected in embryonic rat hippocampal cultures, as well as in acutely dissected embryonic and adult rat hippocampi. Possible transduction pathways mediating the TNF-alpha effect are discussed.
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Affiliation(s)
- F Grassi
- Dipartimento di Medicina Sperimentale, Università di Roma La Sapienza,Italy
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23
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Abstract
The action of 5-hydroxytryptamine (5HT) on nicotinic acetylcholine receptor (nAChR) channels was investigated in mouse myotubes, human cloned TE671/RD cells, and Xenopus laevis oocytes. The decay of the ACh-activated whole-cell currents was reversibly accelerated in the presence of 5HT (10(-5) to 10(-3) M), in a dose-dependent manner. 5HT also reduced the size and accelerated the decay of currents elicited by ACh in Xenopus oocytes injected with mRNA extracted from C2 myotubes or Torpedo electroplaques, or oocytes injected with cloned mouse muscle AChR subunit mRNAs. The effect of 5HT was promptly reversed after washout, or by depolarizing the oocyte beyond -10 mV. In patch-clamp recordings from myotubes, bath-application of 5HT did not exert an indirect influence on the ACh-activated channels within the patch membrane. In contrast, when the patch membrane was exposed to 5HT (10(-6) M), ACh unit responses appeared as bursts of short pulses. It is concluded that the regulation of ACh responses by 5HT results from a fast noncompetitive blocking action of nAChR-channels. These results show that ligand-gated channels, activated by their specific neurotransmitter, may be regulated by a different neurotransmitter through a direct action on the receptor molecule.
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Affiliation(s)
- F Grassi
- Dipartimento Medicina Sperimentale, University of Rome, Italy
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24
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Delpino A, Spinsanti P, Mattei E, Mileo AM, Vismara D, Ferrini U. Identification of a 66 kD heat shock protein (HSP) induced in M-14 human melanoma cells by severe hyperthermic treatment. Melanoma Res 1992; 2:369-75. [PMID: 1292785 DOI: 10.1097/00008390-199212000-00011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Following severe hyperthermic treatment M-14 cells synthesize at high rate a new protein of about 66 kD, in addition to the three well known major HSPs (HSP 28, HSP 70 and HSP 90). This 66 kD protein is constitutively expressed at low levels and its rate of synthesis is not enhanced by mild hyperthermic exposures (40 degrees C for 2-4 h; 42 degrees C for 1-3 h), sufficient to induce the three major HSPs. The 66 kD protein is induced whenever the thermal dose administered to cells attains a threshold, roughly corresponding to a 50% reduction in survival. The 66 kDa protein is not induced by a variety of compounds (disulfiram, arsenate, cadmium) able to elicit a stress response in M-14 cells, as indicated by enhanced synthesis of the three major HSPs. Once induced by a treatment at 45 degrees C for 15 min, the rate of synthesis of the 66 kD protein remains above the control level for 16-20 h during recovery from the stress, while the synthesis of HSP 70 is shut off between 8 and 12 h. Immunoblotting and immunoprecipitation studies showed that the 66 kD protein shares immunological determinant(s) with HSP 70. Pulse-chase experiments demonstrated that the 66 kD protein is not a degradation product or a late post-transcriptional modification of HSP 70. It is proposed that the 66 kD protein is a previously unrecognized heat shock protein (HSP 66), characterized by an unusually high threshold for its induction.
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Affiliation(s)
- A Delpino
- Istituto Regina Elena per lo Studio e la Cura dei Tumori, Laboratorio di Biofisica, Roma, Italy
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25
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Mattei E, Damasi D, Mileo AM, Delpino A, Ferrini U. Stress response, survival and enhancement of heat sensitivity in a human melanoma cell line treated with L-canavanine. Anticancer Res 1992; 12:757-62. [PMID: 1622135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
L-Canavanine, like other aminoacid analogs, induces the synthesis of heat shock proteins (HPSs) but, unlike heat or other stressing agents, it fails to induce thermotolerance. We have studied the synthesis and the intracellular distribution of HSPs induced by canavanine, the effects of this analog on the viability and thermal sensitivity of a human melanoma cell line (M14) and the capacity of canavanine-induced HSPs to self regulate their own synthesis. Evidence indicates that the HSP induction is time--and dose--dependent and, also in the presence of arginine, is not associated with the development of thermotolerance. On the contrary, cells become more heat sensitive and are less efficient in the control of the feed-back mechanism that regulates HSP synthesis. The possible utilization of this substance as a potential aid for the treatment of tumors, in association with heat, was examined.
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Affiliation(s)
- E Mattei
- Istituto Tecnologie Biomediche, C.N.R., Rome, Italy
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26
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Mileo AM, Fanuele M, Battaglia F, Scambia G, Benedetti-Panici C, Mattei E, Mancuso S, Delpino A. Preliminary evaluation of HER-2/neu oncogene and epidermal growth factor receptor expression in normal and neoplastic human ovaries. Int J Biol Markers 1992; 7:47-51. [PMID: 1349908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
The HER-2/neu oncogene (a member of the Erb-like oncogene family) is distinct from but closely related to the c-erb B gene which encodes the epidermal growth factor receptor (EGFr). HER-2/neu gene amplification was found in a large number of mammary carcinomas and there was a strong correlation between this phenomenon and poor prognosis. In our study HER-2/neu oncogene expression was determined in 16 malignant ovarian tumors, 2 ovarian lymphomas and 5 normal ovaries. The HER-2/neu gene was found both in normal ovaries and malignant tumors, without any apparent difference among the various histological types. In all the specimens examined, HER-2/neu expression did not seem to be related to EGF binding capacity.
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Affiliation(s)
- A M Mileo
- Regina Elena Institute for Cancer Research, Roma, Italy
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27
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Giovannelli A, Grassi F, Mattei E, Mileo AM, Eusebi F, Giovanelli A. Acetylcholine induces voltage-independent increase of cytosolic calcium in mouse myotubes. Proc Natl Acad Sci U S A 1991; 88:10069-73. [PMID: 1946425 PMCID: PMC52869 DOI: 10.1073/pnas.88.22.10069] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Electrophysiological, biochemical, and Ca2+ imaging studies of cultured mouse myotubes were used to investigate whether the neurotransmitter acetylcholine causes an increase in intracellular Ca2+ concentration ([Ca2+]i) through activation of a second messenger system. Bath applications of acetylcholine to myotubes (i) elicited a significant membrane current even in a Na(+)-free Ca2+ medium, when the current was carried mainly by calcium ions; (ii) caused a rapid and transient cytosolic accumulation of inositol 1,4,5-trisphosphate; (iii) evoked a conspicuous alpha-bungarotoxin-sensitive long-lasting [Ca2+]i enhancement even in the presence of Cd2+; and (iv) transiently increased [Ca2+]i when cells were equilibrated in a Ca(2+)-free atropine-containing medium. We propose that, in addition to opening ion channels, the nicotinic action of acetylcholine on the muscle cell membrane increases [Ca2+]i through activation of the inositol 1,4,5-trisphosphate second messenger system and mobilization of Ca2+ from intracellular stores.
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Affiliation(s)
- A Giovannelli
- Laboratorio di Biofisica, Centro della Ricerca Sperimentale Istituto Regina Elena, Rome, Italy
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28
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Chersi A, Romano TF, Evangelista M, Mileo AM, Falasca G. Preparation of rabbit antibodies to 4,4'-dimethoxytriphenylmethyl, the protective group in oligonucleotide synthesis. Biol Chem Hoppe Seyler 1991; 372:845-8. [PMID: 1772597 DOI: 10.1515/bchm3.1991.372.2.845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Antibodies were raised in 2 rabbits by immunization with carrier proteins covalently bound to deoxyguanosine bearing a 4,4'-dimethoxytriphenylmethyl group protecting the 5'-hydroxy terminus of deoxyribose. After several injections with such complexes, immune sera were tested with an immuno-enzymatic method using as antigens several compounds containing the hapten, as well as synthetic oligonucleotides bearing, or not, this protective group at the 5' terminus. One of the two antisera appeared to recognize the dimethoxytrityl group bound to carrier molecules, and thus might find a useful application for the detection, quantitation, and control of oligonucleotides obtained by automatic synthesis.
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Affiliation(s)
- A Chersi
- Laboratory of Biochemistry, Regina Elena Institute for Cancer Research, Rome
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29
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Castelli M, Battaglia F, Scambia G, Panici PB, Ferrandina G, Mileo AM, Mancuso S, Ferrini U. Immunosuppressive acidic protein and CA 125 levels in patients with ovarian cancer. Oncology 1991; 48:13-7. [PMID: 1987493 DOI: 10.1159/000226886] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The serum levels of immunosuppressive acid protein (IAP) and CA 125 were determined in 98 patients with ovarian cancer, in 20 patients with benign ovarian tumors and in a group of normal postmenopausal women as controls. On the basis of the mean values of normal controls (346.46 +/- 133.26 micrograms/ml), the IAP threshold was fixed at 613 micrograms/ml. Increased IAP levels were found in 70.4% of patients with ovarian cancer, in 25% of benign tumors and in 4.5% of normal women. Elevated levels of CA 125 were observed in 66.6% of cancers, in 40% of benign tumors and in 6.9% of controls. In particular, in early stage ovarian cancer the combined assay of the two markers increased by about 30% with respect to CA 125 alone. The simultaneous determination of IAP and CA 125 allowed an overall sensitivity of 84% without any significant reduction of specificity.
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Affiliation(s)
- M Castelli
- Regina Elena Cancer Institute, Catholic University, Rome, Italy
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30
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Barbieri R, Giacomini P, Volinia S, Nastruzzi C, Mileo AM, Ferrini U, Soria M, Barrai I, Natali PG, Gambari R. Human HLA-DR alpha gene: a rare oligonucleotide (GTATA) identifies an upstream sequence required for nuclear protein binding. FEBS Lett 1990; 268:51-4. [PMID: 2384172 DOI: 10.1016/0014-5793(90)80970-t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Synthetic oligonucleotides containing putative regulatory sequences are currently employed to identify and isolate genes coding for nuclear binding factors. Upstream DNA sequences of eukaryotic genes required for transcriptional activity and tissue specificity can be identified by means of biochemical techniques as well as computer analysis using homology searching. An alternative approach has been recently proposed by our research group. Scanning DNA sequences 1.8 megabases in length from a Genetic Sequence Data Bank, we have identified rare oligonucleotides 5 base pairs (bp) long, which are localized within or close to regulatory segments in mammalian promoters. In this paper we demonstrate that the rare GTATA sequence identifies an upstream region of the HLA-DR alpha gene which operates in conjunction with the sequence AGAAGTCAG, homologous to a box found in many interferon-inducible genes, in binding nuclear proteins.
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Affiliation(s)
- R Barbieri
- Istituto di Chimica Biologica, Università di Ferrara, Italy
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31
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Mileo AM, Fanuele M, Battaglia F, Scambia G, Benedetti-Panici P, Mancuso S, Ferrini U. Selective over-expression of mRNA coding for 90 KDa stress-protein in human ovarian cancer. Anticancer Res 1990; 10:903-6. [PMID: 2382987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The mRNA expression of the KDa stress-protein (SP) was assayed in normal and neoplastic human ovary. It was found that the expression level is low in normal ovary and in benign tumors and increases in the more advanced stages of ovarian cancer. A low level of mRNA coding for the 70 KDa SP--the most prominent among the inducible SPs-was constantly found in all specimens. No relationship was observed between SP 90 mRNA abundance and the receptor status of epidermal growth factor, estrogen and progesterone.
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Affiliation(s)
- A M Mileo
- Biophysics Laboratory, Regina Elena Institute for Cancer Research, Rome, Italy
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32
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Delpino A, Mattei E, Mileo AM, Ferrini U. Clinical relevance of heat shock proteins. Adv Exp Med Biol 1990; 267:547-57. [PMID: 2088072 DOI: 10.1007/978-1-4684-5766-7_59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- A Delpino
- Istituto Regina Elena per lo Studio e la Cura dei Tumori, Roma, Italy
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33
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Mileo AM, Mattei E, Fanuele M, Delpino A, Ferrini U. Differential radiosensitivity in cultured B-16 melanoma cells following interrupted melanogenesis induced by glucosamine. Pigment Cell Res 1989; 2:167-70. [PMID: 2771876 DOI: 10.1111/j.1600-0749.1989.tb00182.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The relationship between cell pigmentation and radiosensitivity was investigated in a cell model in which melanogenesis was suppressed by a glycosylation inhibitor. It was found that X-irradiation of melanotic B-16 melanoma cells and their amelanotic counterparts, obtained by glucosamine treatment, showed an inverse correlation between radiosensitivity and melanin contents. Since melanogenesis interruption by glucosamine does not affect the DNA repair capacity of nonpigmented cells, it is likely that intracellular melanins play a role in the relative resistance of pigmented cells to X-irradiation.
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Affiliation(s)
- A M Mileo
- Biophysics Laboratory, Regina Elena Cancer Institute, Rome, Italy
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34
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Ferrini U, Mileo AM, Nista A, Mattei E, Orofino A. Polymorphonuclear leukocyte stimulation measured by phage inactivation. Int Arch Allergy Appl Immunol 1989; 90:207-12. [PMID: 2592111 DOI: 10.1159/000235026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A quantitative assay for determining the polymorphonuclear neutrophil (PMN) stimulation is described. The method is based on the inactivation of lambda vector phages that occurs after a brief exposure to stimulated PMNs. The determination of the number of residual plaque-forming units on the appropriate bacterial host allows a reproducible and sensitive quantitative assay for measuring the stimulation level of the PMN. In comparison with other methods that employ bacteria or eukaryotic cells, this assay provides several advantages and can be used for investigating the biochemical and physiological processes responsible for PMN stimulation.
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Affiliation(s)
- U Ferrini
- Laboratory of Biophysics, Regina Elena Institute for Cancer Research, Rome, Italy
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35
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Mattei E, Delpino A, Mileo AM, Ferrini U. Absence of Acquired Thermotolerance in Murine Tumors Unable to Increase the Expression of Heat Shock Proteins following Stress Stimuli. Tumori 1988; 74:513-7. [PMID: 3217985 DOI: 10.1177/030089168807400503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The induction of thermotolerance was studied in two groups of murine tumors, one able to produce heat shock proteins (HSP) and the other entirely lacking HSP expression in response to various stress inducers. Heat treatments were performed in vitro and the development of thermotolerance was then evaluated in vivo. The data obtained on the of death rate of mice inoculated with tumor cells previously conditioned at 42 °C for 1 h and then challenged at 45 °C for 30 min following 2 h of reincubation at 37 °C, show that the rate of survival is far higher in mice inoculated with HSP negative tumor cells. This indicates that a large number of cells able to increase HSP synthesis following stress escape heat killing, whereas cells unable to express HSP after adequate stimuli are less tolerant against heat challenge.
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Affiliation(s)
- E Mattei
- Biophysical Laboratory, Regina Elena Cancer Institute, Rome, Italy
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36
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Ferrini U, Mileo AM, Hearing VJ. Microheterogeneity of melanosome-bound tyrosinase from the Harding-Passey murine melanoma. Int J Biochem 1987; 19:227-34. [PMID: 3109972 DOI: 10.1016/0020-711x(87)90025-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This study was directed towards the characterization of the origin of the microheterogeneity displayed by mammalian tyrosinase, the enzyme responsible for pigmentation in mammals. Tyrosinase was purified from the Harding Passey murine melanoma, fractionated into a continuous series of subisozymic forms, and analyzed using various chemical and immunological probes. Treatment with neuraminidase revealed that all the forms had similar amounts of sialic acid, and reactivity with various carbohydrate specific lectins showed that the isozymes also contained subterminal galactose, N-acetylglucosamine, and mannose, but lacked alpha-fucose. Amino acid composition data indicated that the polypeptides of all the forms had identical residue contents. The sum of the evidence further supports the theory that the isozymic forms demonstrable for mammalian tyrosinase represent intermediate processing stages of the enzyme from the nascent protein chain to the fully glycosylated, high molecular weight form of tyrosinase that is localized within melanin granules.
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37
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Delpino A, Mileo AM, Mattei E, Ferrini U. Characterization of the heat shock response in M-14 human melanoma cells continuously exposed to supranormal temperatures. Exp Mol Pathol 1986; 45:128-41. [PMID: 3770142 DOI: 10.1016/0014-4800(86)90054-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The heat shock response elicited in a human melanoma cell line (M-14) by continuous exposures to supranormal temperatures has been characterized. The electrophoretic patterns of polypeptides labeled in vivo at different time-intervals during a continuous heating at 42 degrees C show that the hyperthermic stress induces the synthesis of three HSPs, with molecular weights, respectively, of 86 kDa, 70-72 kDa and 26 kDa. The relative rate of synthesis of the 70-72 kDa HSP--the preeminent HSP--increases during the first hours of treatment, reaching the maximum value after about 9 hr. Later on, the rate of synthesis of this protein progressively decreases, finally attaining a steady state level only slightly exceeding the constitutive one. On the contrary, the smaller molecular weight HSP is synthesized at an apparently constant rate in the course of 21 hr of heating treatment. A continuous exposure at 40 degrees C induces the synthesis of the same three HSPs observed in cells heated at 42 degrees C, but the rate of synthesis of all these HSPs is not so greatly enhanced over the control values as in the 42 degrees C-heated cells. Moreover, the repression of the 70-72 kDa HSP synthesis is faster, taking place within 4-6 hr of treatment. Coomassie blue stained gels show that a polypeptide, coincident with the 70-72 kDa HSP, accumulates in the course of a continuous heating either at 42 degrees C and at 40 degrees C. The final intracellular level attained by this protein species results higher in 42 degrees C-treated cells than in 40 degrees C-treated ones. Hybridization experiments between total RNAs obtained from cells heated at 42 degrees C and a radioactive DNA probe (containing sequences complementary to the mRNA coding for the human 70 kDa HSP) demonstrate that the kinetics of accumulation and decay of the 70 kDa HSP-mRNAs correlate with the kinetics of induction and repression of the corresponding protein.
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