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Open Access Research article

GU81, a VEGFR2 antagonist peptoid, enhances the anti-tumor activity of doxorubicin in the murine MMTV-PyMT transgenic model of breast cancer

Kristi D Lynn12, D Gomika Udugamasooriya34, Christina L Roland1, Diego H Castrillon5, Thomas J Kodadek37 and Rolf A Brekken126*

Author Affiliations

1 Division of Surgical Oncology, Department of Surgery, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 76259, USA

2 Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 76259, USA

3 Division of Translational Research, Department of Internal Medicine, UT Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 76259, USA

4 Advanced Imaging Research Center, UT Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 76259, USA

5 Department of Pathology, UT Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 76259, USA

6 Department of Pharmacology, UT Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75390, USA

7 Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA

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BMC Cancer 2010, 10:397  doi:10.1186/1471-2407-10-397

Published: 30 July 2010

Abstract

Background

Vascular endothelial growth factor (VEGF) is a primary stimulant of angiogenesis under physiological and pathological conditions. Anti-VEGF therapy is a clinically proven strategy for the treatment of a variety of cancers including colon, breast, lung, and renal cell carcinoma. Since VEGFR2 is the dominant angiogenic signaling receptor, it has become an important target in the development of novel anti-angiogenic therapies. We have reported previously the development of an antagonistic VEGFR2 peptoid (GU40C4) that has promising anti-angiogenic activity in vitro and in vivo.

Methods

In the current study, we utilize a derivative of GU40C4, termed GU81 in therapy studies. GU81 was tested alone or in combination with doxorubicin for in vivo efficacy in the MMTV-PyMT transgenic model of breast cancer.

Results

The derivative GU81 has increased in vitro efficacy compared to GU40C4. Single agent therapy (doxorubicin or GU81 alone) had no effect on tumor weight, histology, tumor fat content, or tumor growth index. However, GU81 is able to significantly to reduce total vascular area as a single agent. GU81 used in combination with doxorubicin significantly reduced tumor weight and growth index compared to all other treatment groups. Furthermore, treatment with combination therapy significantly arrested tumor progression at the premalignant stage, resulting in increased tumor fat content. Interestingly, treatment with GU81 alone increased tumor-VEGF levels and macrophage infiltration, an effect that was abrogated when used in combination with doxorubicin.

Conclusion

This study demonstrates the VEGFR2 antagonist peptoid, GU81, enhances the anti-tumor activity of doxorubicin in spontaneous murine MMTV-PyMT breast tumors.