Chemosensitivity testing of oral cancer cells treated with a p185neu-specific agent.
The amplification and overexpression of the erbB-2 oncogene and its involvement in tumorigenesis makes this receptor an appropriate target for specific agents directed towards tumor cells. The purpose of this study was to evaluate the in vitro effect of the bacterially produced recombinant immunotoxin scFv(FRP5)-ETA on the protein synthesis and adenosine triphosphate (ATP) reduction in oral squamous cell carcinoma (OSCC) cells. This agent recognizes the erbB-2 receptor and inhibits protein synthesis in receptor-overexpressing cells. OSCC cells were selected for this study, and amplification and expression levels of the erbB-2 receptor were determined. Cell suspensions were cultured for 6 d with various concentrations of scFv(FRP5)-ETA (1-1000 ng/ml). A431 and MDA-MB468 cell lines were used as controls. Chemosensibility of tumor cells was measured by [3H]leucine incorporation assay and by an ATP luminescence assay. In OSCC cells with amplification and overexpression of erbB-2 inhibition, up to 92% of protein synthesis and 90% of ATP reduction was observed when cells were exposed to 1,000 ng/ml immunotoxin. In OSCC cells showing a deletion of erbB-2 and in erbB-2-negative MDA-MB468 cells, protein synthesis was inhibited by 22% and 8%, respectively. These results indicate that the effectiveness of a recombinant immunotoxin targeting erbB-2 receptors in OSCC cells depends on the level of erbB-2 amplification and expression, that it is highly specific for tumor cells expressing these receptors, and that a dose-dependency can be observed.
Werkmeister
R
R
Department of Oral and Maxillofacial Surgery, University of Münster, Germany. werkmei@uni-muenster.de
Fillies
T
T
Brandt
B
B
Groner
B
B
Weis
W
W
Joos
U
U
D036002:ADP Ribose Transferases; D000255:Adenosine Triphosphate / Q000037:antagonists & inhibitors; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D001427:Bacterial Toxins / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005098:Exotoxins / Q000627:therapeutic use*; D005784:Gene Amplification; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic; D018734:Genes, erbB-2 / Q000235:genetics; D006801:Humans; D000922:Immunotoxins / Q000627:therapeutic use*; D007930:Leucine / Q000378:metabolism; D008163:Luminescent Measurements; D009062:Mouth Neoplasms / Q000188:drug therapy*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000627:therapeutic use*; D011550:Pseudomonas aeruginosa; D019275:Radiopharmaceuticals; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011994:Recombinant Proteins; D014316:Tritium; D014407:Tumor Cells, Cultured; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A
D036002:ADP Ribose Transferases; D000255:Adenosine Triphosphate; D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D005098:Exotoxins; D000922:Immunotoxins; D007930:Leucine; D009363:Neoplasm Proteins; D011065:Poly(ADP-ribose) Polymerases; D019275:Radiopharmaceuticals; D018719:Erb-b2 Receptor Tyrosine Kinases; D011994:Recombinant Proteins; D014316:Tritium; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A