TRA-8 anti-DR5 monoclonal antibody and gemcitabine induce apoptosis and inhibit radiologically validated orthotopic pancreatic tumor growth

Academic Article

Abstract

  • Purpose: To evaluate agonistic TRA-8 monoclonal antibody to human death receptor 5 (DR5) and gemcitabine in vitro and in an orthotopic pancreatic cancer model. Experimental Design: Pancreatic cancer cell lines were screened for DR5 expression, cytotoxicity, and apoptosis induced by TRA-8, gemcitabine, or gemcitabine and TRA-8. An orthotopic model of pancreatic cancer was established in severe combined immunodeficient mice. Mice were treated with TRA-8, gemcitabine, or a combination for one or two cycles of therapy. Tumor growth (ultrasound) and survival were analyzed. Results: All five pancreatic cancer cell lines showed DR5 protein expression and varying sensitivity to TRA-8-mediated cytotoxicity. MIA PaCa-2 cells were very sensitive to TRA-8, moderately resistant to gemcitabine, with additive cytotoxicity to the combination. S2-VP10 cells were resistant to TRA-8 and sensitive to gemcitabine with synergistic sensitivity to the combination. Combination treatment in vitro produced enhanced caspase-3 and caspase-8 activation. A single cycle of therapy produced comparable efficacy for single-agent TRA-8 and the combination of TRA-8 and gemcitabine, with significant reduction in tumor size and prolonged survival compared with gemcitabine alone or control animals. With two cycles of therapy, TRA-8 and combination therapy produced enhanced inhibition of tumor growth compared with single-agent gemcitabine or untreated animals. However, the combination regimen showed enhanced survival as compared with single-agent TRA-8. Conclusions: Pancreatic cancer cell lines express varying levels of DR5 and differ in their sensitivity to TRA-8 and gemcitabine-induced cytotoxicity. TRA-8 with two cycles of gemcitabine therapy produced the best overall survival. Copyright © 2007 American Association for Cancer Research.
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    Digital Object Identifier (doi)

    Author List

  • DeRosier LC; Vickers SM; Zinn KR; Huang Z; Wang W; Grizzle WE; Sellers J; Stockard CR; Zhou T; Oliver PG
  • Start Page

  • 3198
  • End Page

  • 3207
  • Volume

  • 6
  • Issue

  • 12