Anti-tumor activity of the TRA-8 anti-DR5 antibody in combination with cisplatin in an ex vivo human cervical cancer model.
OBJECTIVE
To investigate the cytotoxicity of TRA-8, an antibody that specifically binds death receptor 5 (DR5), alone and in combination with cisplatin, using an ex vivo human cervical cancer model.


METHODS
Fifteen cervical cancer specimens were obtained at the time of radical hysterectomy and tumor slices were prepared with the Krumdieck tissue slicer. Tumor slices were exposed to varying concentrations of TRA-8, cisplatin, or the combination of TRA-8 and cisplatin. Using non-linear modeling, dose response curves and IC50 values were generated for each specimen treated with TRA-8. The additive cytotoxic effect of combination treatment was evaluated as well. In addition to ATP viability assays, treated and untreated slices were assessed by immunohistochemistry (IHC) and western blot analysis to confirm apoptosis induction via the extrinsic pathway.


RESULTS
Eleven patient specimens yielded TRA-8-induced IC50 values. Sixty-four percent were found to be sensitive to TRA-8-induced cytotoxicity at IC50 doses less than 1000 ng/ml. Seven patient specimens underwent combination treatment with TRA-8 and cisplatin. Of these specimens, 86% exhibited additive cytotoxicity in comparison to treatment with either agent alone. IHC revealed an increase in DR5 expression in tumor slices treated with cisplatin for 24 h. IHC and Western blotting demonstrated TRA-8-induced cell death via apoptosis and activation of caspase 3 and 8.


CONCLUSIONS
This study confirms the utility of an ex vivo human cervical cancer model, to evaluate the anti-tumor activity of TRA-8 and cisplatin. This model may be a useful pre-clinical tool to assess cytotoxicity and mechanistic properties of novel agents in cervical cancer.
Kendrick
James E
JE
Division of Gynecologic Oncology, University of Alabama at Birmingham, Birmingham, AL 35249, USA. tommy.kendrick@obgyn.uab.edu
Straughn
J Michael
JM
Oliver
Patsy G
PG
Wang
Wenquan
W
Nan
Li
L
Grizzle
William E
WE
Stockard
Cecil R
CR
Alvarez
Ronald D
RD
Buchsbaum
Donald J
DJ
D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D002945:Cisplatin / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000276:immunology*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000276:immunology*; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy* / Q000473:pathology
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; D002945:Cisplatin