Innovative Bioluminometric Quantification of Cancer Cell Load in Target Organs: Implications for Studying Anticancer Drugs, Including ROS Enhancers

Abstract

Animal models are essential for developing effective drugs for treating human cancer. Examination of the formation of lung surface foci of B16-F10 melanoma cells is a widely used animal model for studying cancer metastasis and drug intervention. This model, however, suffers from several drawbacks, including its non-quantitative nature and inability to yield information on cancer cell load inside the target organ. Here we report the development of a highly sensitive, bioluminescence-based method for quantifying melanoma cell load in mouse lungs following intravenous injection of luciferase-expressing B16-F10 melanoma cells. This method could readily detect as few as 1–10 cells in the samples and enable quantification of cancer cell load before the formation of surface foci in mouse lungs following metastasis of intravenously inoculated B16-F10 melanoma cells. This innovative bioluminometry-based method has important implications for studying anticancer drugs, including naturally occurring redox-active quinones that generate reactive oxygen species to kill cancer cells.

Nrf2 Deficiency Promotes Melanoma Growth and Lung Metastasis

“…We also applied a recently developed highly sensitive bioluminometric assay [9] to determine lung metastasis by quantifying the melanoma cell load in mouse lungs following subcutaneous inoculation. Our results demonstrated for the first time that Nrf2 deficiency significantly promoted the growth of subcutaneously inoculated B16-F10 cells as indicated by increased proportion of animals with locally palpable tumor mass and time-dependent increases in tumor volume at the injection site.…”

“…The luciferase/luciferin-derived bioluminescence intensity was expressed as integrated responses (total counts of photon emission) over the above 5 min. The melanoma cell load per mouse lungs was determined by using a concurrently run standard curve of known numbers of B16-F10 cells as described previously [9]. …”

A Simple Bioluminescence Imaging Method for Studying Cancer Cell Growth and Metastasis after Subcutaneous Injection of Lewis Lung Carcinoma Cells in Syngeneic C57BL/6 Mice

“…For internal organs that do not emit enough photons (due to small number of cancer cells metastasized) to penetrate the tissues so as so be captured by the camera, such organs can be collected and ex vivo imaging be obtained. In addition, the exact number of cancer cells metastasized to an internal organ can be determined by the quantitative bioluminometry as described before [7]. …”