Evaluation of a preclinical model of bone metastasis for the study of adoptive immunotherapy

The development of new therapeutic strategies for the treatment of bone metastases strongly depends on the availability of valid animal models. In this paper, we evaluate a preclinical model of bone metastases using a technique of tumor cell injection into the left heart ventricle of mice to study the efficacy of adoptive immunotherapy. Using flow cytometric analysis and histopathological and radiological examination, we investigated whether this experimental model of bony metastases using two murine cell lines of melanoma and breast cancer would be suitable for the study of adoptive immunotherapy for these diseases. We further report that anti-CD3-activated and IL-2-expanded tumor vaccine draining lymph node cells cause regression of tumor metastases, including bone metastases, following adoptive transfer to mice bearing 3-day metastases from the D5 melanoma cell line. These promising early results lead us to conclude the following: (1). this model of experimental bone metastases is suitable for the study of immunotherapy, and (2). further studies are warranted to extend these promising early findings of the therapeutic effects of adoptive immunotherapy in this animal model.