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

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

In vitro culturing human Mesenchymal Stem Cells on 3D scaffolds for bone tissue regeneration

In vitro culturing human Mesenchymal Stem Cells on 3D scaffolds for bone tissue regeneratio

Improvement of idiopathic pyoderma gangrenosum during treatment with anti-tumor necrosis factor alfa monoclonal antibody

Pyoderma gangrenosum (PG) is an inflammatory ulcerative condition of unknown etiology. An autoimmune mechanism including immune complex–mediated neutrophilic vascular reactions has been suggested. The role of tumor necrosis factor (TNF) in PG remains unclear. Evidence supports the idea that TNF plays a role in chronic inflammation and migration of neutrophils to these lesions. PG is frequently associated with various diseases, but up to 50% of cases are idiopathic. There are several reports describing the successful use of infliximab™(Remicade®, Centocor, Inc, Horsham, Pa), a chimeric antitumor necrosis factor α monoclonal antibody, in the treatment of inflammatory bowel disease– associated PG, but there have been few reported cases of infliximab in the treatment of idiopathic PG. The authors present a dramatic improvement in 4 cases of idiopathic PG of the lower leg treated with infliximab

Antimicrobial lipase antibody their nucleotide and aminoacid sequences and uses thereof

PATENT PCT. 2002; EPO2_1214