Visualizing the kinetics of tumor-cell clearance in living animals

Evaluation of potential antineoplastic therapies would be enhanced by nonin vasive detection of tumor cells in living animals. Because light is transmi tted through mammalian tissues, it was possible to use bioluminescence to m onitor (both externally and quantitatively) growth and regression of labele d human cervical carcinoma (HeLa) cells engrafted into immunodeficient mice . The efficacy of both chemotherapy and immunotherapeutic treatment with ex vivo expanded human T cell-derived effector cells was evaluated. In the ab sence of therapy, animals showed progressive increases in signal intensity over time. Animals treated with cisplatin had marked reductions in tumor si gnal; 5'-fluorouracil was less effective, and cyclophosphamide was ineffect ive. Immunotherapy dramatically reduced signals at high effector-to-target cell ratios, and significant decreases were observed with lower ratios. Thi s model system allowed sensitive, quantitative, real-time spatiotemporal an alyses of the dynamics of neoplastic cell growth and facilitated rapid opti mization of effective treatment regimens.