Linked Life Data

10200532

Source:http://linkedlifedata.com/resource/pubmed/id/10200532

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1999-5-28
pubmed:abstractText
Many anticancer drugs are able to induce apoptosis in tumor cells but the mechanisms underlying this phenomenon are poorly understood. Some authors reported that the p53 tumor suppressor gene may be responsible for drug-induced apoptosis; however, chemotherapy-induced apoptosis can also be observed in p53 negative cells. Recently, doxorubicin (DXR) was reported to induce CD95L expression to mediate apoptosis through the CD95/CD95L system. Thus, an impairment of such a system may be involved in drug resistance. We evaluated the in vitro antitumor activity of several cytotoxic drugs on two human p53-negative T-cell lymphoma cell lines, the HUT78-B1 CD95L-resistant cell line and the HUT78 parental CD95L-sensitive cell line. We demostrated by Western blotting assay that DXR and etoposide (VP-16) were able to induce CD95L expression after 4 h of treatment. In contrast, they were unable to induce the expression of p53. DXR, at concentrations ranging from 0.001 - 1 microg/ml, and VP16, at concentrations ranging from 0.05 - 1 microg/ml, were equally cytotoxic and induced apoptosis in both cell lines as assessed by fluorescence microscopy and flow cytometry analyses. Although we observed a slightly reduced percentage of apoptotic cells in HUT78B1 when compared with the parental HUT78 cells after few hours of drug exposure, this difference was no longer evident at 48 or 72 h. Similarly, the exposure of HUT78 cells to a CD95-blocking antibody partially reduced early apoptosis (24 h) without affecting the long-term effects of the drugs including cytotoxicity. Furthermore, as observed with DXR and VP-16, both the CD95L-sensitive and the CD95L-resistant cell lines resulted equally sensitive to the cytotoxic effects of a number of different cytotoxic drugs (vincristine, camptothecin, 5-fluorouracil and methotrexate). The treatment with the Caspase-3 tetrapeptide aldehyde inhibitor, Ac-DEVD-CHO, did not affect the DXR-induced apoptosis whereas it only modestly inhibited apoptosis and cytotoxicity of VP-16, while Z-VAD.FMK, a Caspase inhibitor that prevents the processing of Caspase-3 to its active form, was able to block DXR-induced apoptosis at 24 h but not at 48 h. Thus, our results do not confirm a crucial role for the CD95/CD95L system in drug-induced apoptosis and suggest the involvement of alternative p53-independent pathways at least in this experimental model system.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Antigens, CD95, http://linkedlifedata.com/resource/pubmed/chemical/Antineoplastic Agents, http://linkedlifedata.com/resource/pubmed/chemical/CASP3 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Caspase 3, http://linkedlifedata.com/resource/pubmed/chemical/Caspases, http://linkedlifedata.com/resource/pubmed/chemical/Doxorubicin, http://linkedlifedata.com/resource/pubmed/chemical/Etoposide, http://linkedlifedata.com/resource/pubmed/chemical/FASLG protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Fas Ligand Protein, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Glycoproteins, http://linkedlifedata.com/resource/pubmed/chemical/Proto-Oncogene Proteins c-bcl-2, http://linkedlifedata.com/resource/pubmed/chemical/Tumor Suppressor Protein p53
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1350-9047
pubmed:author
pubmed:issnType
Print
pubmed:volume
5
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
735-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
The CD95/CD95 ligand system is not the major effector in anticancer drug-mediated apoptosis.
pubmed:affiliation
Chair of Hematology, University of Palermo, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't