The use of molecular imaging to evaluate the efficacy of treatments for metastatic breast cancer

Abstract

The development of molecular imaging technologies has allowed biomedical researchers to study the process of cancer metastasis in animal models of disease. Bioluminescence imaging has been a crucial tool for non-invasive monitoring of tumor growth, dissemination, and response to therapies. In this report, we have applied bioluminescence imaging to evaluate the efficacy of Death Receptor 5 agonist therapy for the treatment of breast cancer metastasis, predominately to the skeleton, in an athymic nude mouse model. Initially, we determined that bioluminescence imaging was the most ideal technology for studying secondary bone lesions in vivo when compared to both x-ray Computed Tomography and SPECT-CT imaging. Through analysis of histologic sections, bioluminescent images, and markers of bone resorption, therapy studies revealed that murine death receptor 5 agonist mTRA8 and its humanized version hTRA8 significantly reduce tumor burden in mice with experimental metastatic lesions in osseous tissues when combined with zoledronic acid. In a second study, mTRA8 resulted in a significant amount of tumor regression in an in vivo model of lung metastasis. From this work we have concluded that Death Receptor 5 agonist therapy is a promising treatment for breast cancer metastasis in animal models of this human disease and should be evaluated in a clinical setting.