An Immunotolerant HER-2/neuTransgenic Mouse Model of Metastatic Breast Cancer

Abstract

Purpose: Animal models of breast cancer metastases that recapitulate the pattern of metastatic progression seen in patients are lacking; metastatic breast cancer models do not currently exist for evaluation of immune-mediated therapies. We have developed and characterized a preclinical model for the evaluation of immune-mediated metastatic breast cancer therapies. Experimental Design: The NT2.5 mammary tumor cell line was injected into the left cardiac ventricle of immunotolerant transgenic neu-N mice and athymic nu/nu mice. Metastatic progression was monitored by bioluminescent, small-animal magnetic resonance imaging, positron emission tomography, single-photon emission computed tomography/computed tomography imaging, and also by histopathology. Antigen expression in normal organs and tumor metastases was evaluated by Western blot analysis and flow cytometry. Results: Left cardiac ventricle injection of NT2.5 cells yielded widespread metastases in bones, liver, and spleen. Three to four weeks after injection, mice exhibited hind limb paralysis and occasional abdominal enlargement. Bioluminescence imaging of metastatic progression was successful in nude mice but the bioluminescent cells were rejected in immunocompetent mice. Other imaging modalities allowed successful imaging of nonbioluminescent cells. Small-animal positron emission tomography imaging allowed visualization of disease, in vivo, in the bones and liver. Magnetic resonance imaging revealed initial dissemination of the tumor cells to the bone marrow. Small-animal single-photon emission computed tomography/computed tomography imaging identified metastatic bone lesions targeted by a radiolabeled antibody. Conclusion: The model closely recapitulates the pattern of metastatic spread in breast cancer. This immunotolerant metastatic model is a novel addition to existing breast cancer models and coupling the model with in vivo imaging greatly facilitates the evaluation of targeted immunotherapies of metastasis.

Targeting Aberrant DNA Double-Strand Break Repair in Triple-Negative Breast Cancer with Alpha-Particle Emitter Radiolabeled Anti-EGFR Antibody

“…The radiolabeling reaction was quenched with 1 µl of 100 mmol/L EDTA and radiolabeled Cetuximab was purified by size exclusion Microspin G-25 column (GE Healthcare, Buckinghamshire, UK). Cetuximab was also radiolabeled with 111 In (PerkinElmer, Waltham, MA) according to a published procedure (28). The reaction efficiency and purity of the radioimmunoconjugates was determined with instant thin layer chromatography (ITLC) using silica gel impregnated paper (Agilent Technologies, Lake Forest, CA).…”

Radioimmunotherapy of Breast Cancer Metastases with α-Particle Emitter 225Ac: Comparing Efficacy with 213Bi and 90Y

“…In this study, we demonstrate the efficacy of 225 Ac-7.16.4 in targeting rat HER-2/ neu positive pulmonary metastases. Rat HER-2/ neu is also expressed on normal lung tissue in this mouse model as determined by Western blot (17). This allows for evaluating efficacy and toxicity of 225 Ac-7.16.4 in a model that closely mimics clinical cases where cross reactivity of tumor antigen expressed on normal organs is common.…”

Localized sclerotic bone response demonstrated reduced nanomechanical creep properties

“…There is a lack of knowledge of the mechanical property changes associated with sclerotic development since earlier models of osteolytic bone metastasis does not involve reports of sclerosis (Neudert et al, 2003;Arrington et al, 2006;Bä uerle et al, 2005;Neudert et al, 2003;Song et al, 2008). In this study, we have developed a sclerotic bone response using an immunocompetent animal model and characterized its histomorphometric, densitometric, microarchitectural, as well as elastic and viscoelastic property changes.…”