Paclitaxel (Taxol)-induced apoptosis in human epithelioid sarcoma cell lines is enhanced by upregulation of CD95 ligand (FasL/Apo-1L).
OBJECTIVE
Metastasizing epithelioid sarcoma (ES) is an extremely aggressive tumor, because conventional chemotherapy and irradiation are largely ineffective. Here, we analyzed the impact of the CD95-mediated drug-induced apoptosis in ES cell lines.


METHODS
The effects of paclitaxel (Taxol) and 5-FU were determined by MTT assay. The extent of apoptosis was analyzed by light microscopy and Annexin V staining (flow cytometry). The expression of death receptors and ligands was defined by RT-PCR, Western blotting and flow cytometry.


RESULTS
All cell lines expressed CD95, but not the CD95 ligand. The CD95 activation resulted in apoptosis and cell death in all cell lines. Both paclitaxel and 5-FU are able to trigger apoptosis, and furthermore, to upregulate CD95, whereas only paclitaxel increases CD95 ligand expression. Neutralizing antibodies directed against CD95 ligand effectively inhibited paclitaxel-induced cell death, thereby providing evidence for a direct involvement of the CD95 system in paclitaxel-induced apoptosis.


CONCLUSIONS
Concomitant upregulation of CD95 receptor and ligand may significantly enhance the response of ES to anticancer drugs. As evident from the differential response of our clonal ES subpopulations to paclitaxel and 5-FU, effective activation of the CD95 system depends on intrinsic properties of both the chemotherapeutic agent and target cell population.
Heikaus
Sebastian
S
Institute of Pathology, Heinrich Heine-University, Moorenstr. 5, Bldg. 14.79, 40225 Duesseldorf, Germany.
Matuszek
Krystian S
KS
Suschek
Christoph V
CV
Ramp
Uwe
U
Reinecke
Petra
P
Grinstein
Edgar
E
Haremza
Janine
J
Gabbert
Helmut E
HE
Mahotka
Csaba
C
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D053222:Fas Ligand Protein / Q000235:genetics / Q000502:physiology*; D005472:Fluorouracil / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D012509:Sarcoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D015854:Up-Regulation; D019014:fas Receptor / Q000235:genetics / Q000502:physiology
D000972:Antineoplastic Agents, Phytogenic; D053222:Fas Ligand Protein; D012333:RNA, Messenger; D019014:fas Receptor; D017239:Paclitaxel; D005472:Fluorouracil