The immunocytokine scFv23/TNF targeting HER-2/neu induces synergistic cytotoxic effects with 5-fluorouracil in TNF-resistant pancreatic cancer cell lines.
Human pancreatic tumor cells are highly resistant to both tumor necrosis factor (TNF) and to chemotherapeutic agents. HER-2/neu expression has been proposed as a negative prognostic marker in pancreatic intraepithelial neoplasia. Our approach was to utilize HER-2/neu expression on the surface of tumor cells as a therapeutic target employing scFv23/TNF, immunocytokine composed of a single chain Fv antibody (scFv23) targeting the HER-2/neu and the cytokine TNF as the cytotoxic moiety, to deliver TNF directly to TNF-resistant pancreatic tumor cells. Using a panel of human pancreatic cell lines, which overexpress HER-2/neu, we evaluated the in vitro response of cells to TNF, scFv23/TNF, Herceptin, and a combination of scFv23/TNF with various chemotherapeutic agents. We found that all pancreatic cancer cell lines were highly resistant to the cytotoxic effects of TNF and that scFv23/TNF was highly cytotoxic to TNF-resistant HER-2/neu-expressing pancreatic cancer cell lines at levels rivaling that of conventional chemotherapeutic agents. Combination studies demonstrated a synergistic cytotoxic effect of scFv23/TNF with 5-fluorouracil (5-FU) in TNF-resistant pancreatic cancer cell lines. Mechanistic studies demonstrated that the 5-FU plus scFv23/TNF combination specifically resulted in a down-regulation of HER-2/neu, p-Akt and Bcl-2 and up-regulation of TNF-R1. In addition, the combination 5-FU plus scFv23/TNF induced apoptosis and this synergistic effect was dependent on activation of caspase-8 and caspase-3. Delivery of the cytokine TNF to HER-2/neu expressing pancreatic tumor cells, which are inherently resistant to TNF using scFv23/TNF may be an effective therapy for pancreatic cancer especially when utilized in combination with 5-FU.
Lyu
Mi-Ae
MA
Immunopharmacology and Targeted Therapy Laboratory, Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0044, Houston, TX 77030, USA.
Kurzrock
Razelle
R
Rosenblum
Michael G
MG
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D007128:Immunoglobulin Fragments / Q000494:pharmacology*; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D005472:Fluorouracil; D007128:Immunoglobulin Fragments; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; C055966:immunoglobulin Fv