Efficacy of anti-death receptor 5 (DR5) antibody (TRA-8) against primary human ovarian carcinoma using a novel ex vivo tissue slice model.

Abstract

OBJECTIVES:

The purpose of this study was to evaluate the cytotoxicity of a death receptor 5 (DR5) targeting monoclonal antibody (TRA-8) in primary ovarian cancer specimens utilizing a tissue slice technique that allows for assessment of anti-tumor activity in a three-dimensional ex vivo model.

METHODS:

Nineteen primary ovarian tumor specimens were obtained at the time of cytoreductive surgery and tumor slices were prepared with the Krumdieck tissue slicer. Tumor slices were incubated with TRA-8 for 24 h and a dose-response curve was established for each specimen using non-linear modeling, with IC50 values used as the parameter of TRA-8 sensitivity. In parallel with ATP viability assays, TRA-8 treated and untreated tumor slices were assessed by immunohistochemistry (IHC) and western blot analysis to confirm apoptosis induction.

RESULTS:

Incubation with 0-1000 ng/ml TRA-8 resulted in a dose response with maximum killing observed at 1000 ng/ml compared to untreated control slices. IC50 values of 6.0 to >1000 ng/ml were calculated for individual tumor specimens. H&E, IHC, and western blot specimens demonstrated TRA-8-induced cellular death in a dose-dependent fashion via apoptosis and activation of caspases 3, 8, and 9. The apoptosis produced by varying concentrations of TRA-8 was confirmed using the TUNEL technique. Treatment with TRA-8 markedly reduced proliferation in the ovarian cancer cells as measured by expression of Ki-67/SP6.

CONCLUSIONS:

This study demonstrates that targeting DR5 with TRA-8 decreases cellular proliferation, increases caspase activation, and induces apoptosis in this novel three-dimensional ex vivo model of primary ovarian cancer.

• Authors: Jacob M Estes, Patsy G Oliver, J Michael Straughn Jr, Tong Zhou, Wenquan Wang, William E Grizzle, Ronald D Alvarez, Cecil R Stockard, Albert F LoBuglio, Donald J Buchsbaum
• Journal: Gynecologic oncology (Gynecol Oncol) Vol. 105 Issue 2 Pg. 291-8 (May 2007) ISSN: 0090-8258 [Print] United States
• PMID: 17303227 (Publication Type: Journal Article)

Chemical References

• Antibodies, Monoclonal
• Receptors, TNF-Related Apoptosis-Inducing Ligand

Topics

• Adult
• Aged
• Aged, 80 and over
• Antibodies, Monoclonal (immunology, pharmacology)
• Blotting, Western
• Drug Screening Assays, Antitumor
• Female
• Humans
• Immunohistochemistry
• Inhibitory Concentration 50
• Middle Aged
• Ovarian Neoplasms (immunology, pathology, therapy)
• Receptors, TNF-Related Apoptosis-Inducing Ligand (immunology)