Chimeric toxins inhibit growth of primary oral squamous cell carcinoma cells.
Treatment of oral squamous cell carcinoma (OSCC) is currently based on surgery and radiotherapy. Prolongation of the survival time of patients with progressing tumors is infrequently achieved. To improve the therapeutic options, targeted therapies are a favorable alternative. Therefore, we analyzed the effect of a chimeric toxin (CT) named SE consisting of the epidermal growth factor and the plant protein toxin saporin from Saponaria officinalis. A second construct (SA2E) additionally contains a peptidic adapter designed to enhance efficacy of the CT in vivo and to reduce side effects. The IC(50) values for an OSCC cell line (BHY) were 0.27 nM and 0.73 nM for SE and SA2E, respectively, while fibroblasts remained unaffected. To investigate primary tumor cells, we developed a technique to analyze freshly prepared OSCC cells of 28 patients in a stem cell assay directly after surgery. Cells were treated for 1 h with the CTs, subsequently seeded into soft agar and colony growth determined after 1-2 weeks In spite of the short time of CT incubation, the amount of colonies was reduced to about 78% by 10 nM and to 69% by 100 nM of either toxin. A combined application of 10 nM SA2E with a saponin from Gypsophila paniculata reduced the amount of surviving cells to 68%. The results demonstrate the impact of the CTs on OSCC cells and depict that the stem cell assay is suitable to determine the potential of anti-tumor drugs before studies in vivo will be initiated.
Zentralinstitut für Laboratoriumsmedizin und Pathobiochemie, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
Christopher
C
Bachran
Iring
I
Heisler
Diana
D
Bachran
Katrin
K
Dassler
Jürgen
J
Ervens
Matthias F
MF
Melzig
Hendrik
H
Fuchs
D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003114:Colony-Forming Units Assay; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D004815:Epidermal Growth Factor / Q000302:isolation & purification / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D000922:Immunotoxins / Q000737:chemistry / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D009062:Mouth Neoplasms / Q000188:drug therapy*; D012503:Saponins / Q000302:isolation & purification / Q000494:pharmacology*; D013997:Time Factors
D004338:Drug Combinations; D000922:Immunotoxins; D012503:Saponins; D004815:Epidermal Growth Factor