1. Academic Validation
  2. MK-1775, a potent Wee1 inhibitor, synergizes with gemcitabine to achieve tumor regressions, selectively in p53-deficient pancreatic cancer xenografts

MK-1775, a potent Wee1 inhibitor, synergizes with gemcitabine to achieve tumor regressions, selectively in p53-deficient pancreatic cancer xenografts

  • Clin Cancer Res. 2011 May 1;17(9):2799-806. doi: 10.1158/1078-0432.CCR-10-2580.
N V Rajeshkumar 1 Elizabeth De Oliveira Niki Ottenhof James Watters David Brooks Tim Demuth Stuart D Shumway Shinji Mizuarai Hiroshi Hirai Anirban Maitra Manuel Hidalgo
Affiliations

Affiliation

  • 1 Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. rnv1@jhmi.edu
Abstract

Purpose: Investigate the efficacy and pharmacodynamic effects of MK-1775, a potent Wee1 Inhibitor, in both monotherapy and in combination with gemcitabine (GEM) using a panel of p53-deficient and p53 wild-type human pancreatic Cancer xenografts.

Experimental design: Nine individual patient-derived pancreatic Cancer xenografts (6 with p53-deficient and 3 with p53 wild-type status) from the PancXenoBank collection at Johns Hopkins were treated with MK-1775, GEM, or GEM followed 24 hour later by MK-1775, for 4 weeks. Tumor growth rate/regressions were calculated on day 28. Target modulation was assessed by Western blotting and immunohistochemistry.

Results: MK-1775 treatment led to the inhibition of Wee1 kinase and reduced inhibitory phosphorylation of its substrate Cdc2. MK-1775, when dosed with GEM, abrogated the checkpoint arrest to promote mitotic entry and facilitated tumor cell death as compared to control and GEM-treated tumors. MK-1775 monotherapy did not induce tumor regressions. However, the combination of GEM with MK-1775 produced robust antitumor activity and remarkably enhanced tumor regression response (4.01-fold) compared to GEM treatment in p53-deficient tumors. Tumor regrowth curves plotted after the drug treatment period suggest that the effect of the combination therapy is longer-lasting than that of GEM. None of the agents produced tumor regressions in p53 wild-type xenografts.

Conclusions: These results indicate that MK-1775 selectively synergizes with GEM to achieve tumor regressions, selectively in p53-deficient pancreatic Cancer xenografts.

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