53 research outputs found
Manumycin inhibits ras signal transduction pathway and induces apoptosis in COLO320-DM human colon tumourcells
The aim of the present study was to assess the cytotoxicity of manumycin, a specific inhibitor of farnesyl:protein transferase, as well as its effects on protein isoprenylation and kinase-dependent signal transduction in COLO320-DM human colon adenocarcinoma which harbours a wild-type K- ras gene. Immunoblot analysis of isolated cell membranes and total cellular lysates of COLO320-DM cells demonstrated that manumycin dose-dependently reduced p21 ras farnesylation with a 50% inhibitory concentration (IC50) of 2.51 ± 0.11 μM and 2.68 ± 0.20 μM, respectively, while the geranylgeranylation of p21 rhoA and p21 rap1 was not affected. Manumycin dose-dependently inhibited (IC50= 2.40 ± 0.67 μM) the phosphorylation of the mitogen-activated protein kinase/extracellular-regulated kinase 2 (p42MAPK/ERK2), the main cytoplasmic effector of p21 ras, as well as COLO320-DM cell growth (IC50= 3.58 ± 0.27 μM) without affecting the biosynthesis of cholesterol. Mevalonic acid (MVA, 100 μM), a substrate of the isoprenoid synthesis, was unable to protect COLO320-DM cells from manumycin cytotoxicity. Finally, manumycin 1–25 μM for 24–72 h induced oligonucleosomal fragmentation in a dose- and time-dependent manner and MVA did not protect COLO320-DM cells from undergoing DNA cleavage. The present findings indicate that the inhibition of p21 ras processing and signal transduction by manumycin is associated with marked inhibition of cell proliferation and apoptosis in colon cancer cells and the effect on cell growth does not require the presence of a mutated ras gene for maximal expression of chemotherapeutic activity. © 2000 Cancer Research Campaig
Somatic mutations of thymic epithelial tumors with myasthenia gravis
BackgroundThymic epithelial tumors are rare malignant neoplasms that are frequently associated with paraneoplastic syndromes, especially myasthenia gravis. GTF2I is an oncogene mutated in a subgroup of thymomas that is reputed to drive their growth. However, for GTF2I wild-type tumors, the relevant mutations remain to be identified.MethodsWe performed a meta-analysis and identified 4,208 mutations in 339 patients. We defined a panel of 63 genes frequently mutated in thymic epithelial tumors, which we used to design a custom assay for next-generation sequencing. We sequenced tumor DNA from 67 thymomas of patients with myasthenia gravis who underwent resection in our institution.ResultsAmong the 67 thymomas, there were 238 mutations, 83 of which were in coding sequences. There were 14 GTF2I mutations in 6 A, 5 AB, 2 B2 thymomas, and one in a thymoma with unspecified histology. No other oncogenes showed recurrent mutations, while sixteen tumor suppressor genes were predicted to be inactivated. Even with a dedicated assay for the identification of specific somatic mutations in thymic epithelial tumors, only GTF2I mutations were found to be significantly recurrent.ConclusionOur evaluation provides insights into the mutational landscape of thymic epithelial tumors, identifies recurrent mutations in different histotypes, and describes the design and implementation of a custom panel for targeted resequencing. These findings contribute to a better understanding of the genetic basis of thymic epithelial tumors and may have implications for future research and treatment strategies
Increased production of inflammatory cytokines by circulating monocytes in mesial temporal lobe epilepsy: A possible role in drug resistance
: We analyzed peripheral blood mononuclear cells (PBMCs) and serum inflammatory biomarkers in patients with mesial temporal lobe epilepsy (drug-resistant - DR, vs. drug-sensitive - DS). Patients with epilepsy showed higher levels of serum CCL2, CCL3, IL-8 and AOPP, and lower levels of FRAP and thiols compared to healthy controls (HC). Although none of the serum biomarkers distinguished DR from DS patients, when analysing intracellular cytokines after in vitro stimulation, DR patients presented higher percentages of IL-1β and IL-6 positive monocytes compared to DS patients and HC. Circulating innate immune cells might be implicated in DR epilepsy and constitute potential new targets for treatments
Interaction between gemcitabine and topotecan in human non-small-cell lung cancer cells: effects on cell survival, cell cycle and pharmacogenetic profile
The pyrimidine analogue gemcitabine is an established effective agent in the treatment of non-small-cell lung cancer (NSCLC). The present study investigates whether gemcitabine would be synergistic with the topoisomerase I inhibitor topotecan against the NSCLC A549 and Calu-6 cells. Cells were treated with gemcitabine and topotecan for 1 h and the type of drug interaction was assessed using the combination index (CI). Cell cycle alterations were analysed by flow cytometry, while apoptosis was examined by the occurrence of DNA internucleosomal fragmentation, nuclear condensation and caspase-3 activation. Moreover, the possible involvement of the PI3K-Akt signalling pathway was investigated by the measurement of Akt phosphorylation. Finally, quantitative, real-time PCR (QRT-PCR) was used to study modulation of the gemcitabine-activating enzyme deoxycytidine kinase (dCK) and the cellular target enzyme ribonucleotide reductase (RR). In results, it was found that simultaneous and sequential topotecan → gemcitabine treatments were synergistic, while the reverse sequence was antagonistic in both cell lines. DNA fragmentation, nuclear condensation and enhanced caspase-3 activity demonstrated that the drug combination markedly increased apoptosis in comparison with either single agent, while cell cycle analysis showed that topotecan increased cells in S phase. Furthermore, topotecan treatment significantly decreased the amount of the activated form of Akt, and enhanced the expression of dCK (+155.0 and +115.3% in A549 and Calu-6 cells, respectively), potentially facilitating gemcitabine activity. In conclusion, these results indicate that the combination of gemcitabine and topotecan displays schedule-dependent activity in vitro against NSCLC cells. The gemcitabine → topotecan sequence is antagonistic while drug synergism is obtained with the simultaneous and the sequential topotecan → gemcitabine combinations, which are associated with induction of decreased Akt phosphorylation and increased dCK expression
La pubblicità commerciale dopo l’istituzione del registro delle imprese, Giurisprudenza Commerciale,
Il lavoro illustra la disciplina della pubblicità dell'impresa commerciale introdotta con l'istituzione del registro delle impres
In tema di diritto di ispezione del socio sulle deleghe assembleari (nota a C. Cass., 20 giugno 2000, n. 8370)
La nota commenta una decisione della Corte di Cassazione in tema di diritto di ispezione del socio di società di captali sui documenti allegati al verbale assembleare, con particolare riferimento alle deleghe rilasciate dai soc
Il "nuovo" registro delle imprese e gli obblighi di pubblicità dell'imprenditore agricolo
Il lavoro commenta le novità introdotte dalla disciplina sul registro delle imprese con particolare riferimento alla pubblicità dell'impresa agricol
Il fallimento dell’ex-socio dopo le sentenze della Corte Costituzionale n. 66/1999 e n. 319/2000 ( e dopo la riforma della legge sull’amministrazione straordinaria delle grandi imprese in stato di insolvenza)
Il lavoro affronta il problema del trattamento in ambito fallimentare delle responsabilità gravanti sugli ex-soci di società a responsabilità limitata alla luce della decisione resa in materia dalla Corte Costituzional
Prefazione a "Il diritto dell'impresa in crisi fra contratto, società e procedure concorsuali"
Il lavoro illustra in forma sintetica i profili di maggiore interesse, unitamente alle criticità tuttora esistenti, concernenti il recente processo di riforma del sistema concorsuale italian
L’art. 130 del T.U. delle disposizioni in materia di intermediazione finanziaria: i nuovi confini del diritto di informazione del socio
Il lavoro commenta la disciplina del diritto di informazione pre-assebleare del socio di società quotate nell'ambito di una più generale indagine sul regime dell'informazione societari
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