Whole animal non-invasive imaging contributes significantly to understand tumor behavior. It also plays a critical role in drug discovery and development. Optical imaging is convenient because it does not require radioactive materials for imaging. Especially in preclinical applications, optical imaging can be a very useful tool because genetic modification is feasible. The most popular optical imaging is using bioluminescence. We introduced various cancer cell lines that express firefly luciferase. These cells have stable expression of light emission for prolonged cell culture situation. This enables for researchers to implant the cells into animals and to monitor tumor development and metastasis. In addition, these tumor cells can be detected using fluorescent agents that target tumor cells. As a consequence, one can co-register both bioluminescent and fluorescent images. Cells also can be labeled both bioluminescent and fluorescent markers such as luciferases and fluorescent proteins. Although there are many different types of cell lines available for different tumor types, studying metastasis can be challenging. That is mainly because most popular cell lines show delayed metastasis when implanted in the animal. To expedite the metastasis, intravenous injection or intracardiac injection is performed to generate secondary tumors in the animal. However, these methods do not represent true metastasis from originated organs. One of the most popular breast cancer cell line is MDA-MB-231. When these cells are implanted into mammary fat pads of female nude mice, it typically takes more than 90 days to detect metastasis in the secondary sites. Therefore, to study the tumor behavior or to examine the drug efficacy, one should wait for a long time to see the metastasis. Here, we generated tumor cell lines that were derived from MDA-MB-231 originated cells. We took MDA-MB-231 cells that were labeled with either luciferase (MDA-MB-231-luc2) or luciferase & tdTomato fluorescent protein (MDA-MB-231-luc2-tdTomato). These cells were implanted into mammary fat pads of nude mice and secondary tumors were isolated from lymph nodes. Tissues were dissociated to single cells and clonal cell lines were established (MDA-MB-231-luc2-LN and MDA-MB-231-luc2-tdTomato-LN). The growth patterns of these cells were compared to their corresponding parental cells. To find out the metastasis patterns of these cells, we implanted new cell lines orthotopically into nude mice. Our results showed that these cell lines showed faster metastases than parental cell lines. Moreover, we examined biomarker expression patterns with multiplexing multispectral microscopy. These cells can be used to study tumor metastasis and drug discovery using non-invasive in vivo imaging.

Citation Format: Jae Beom Kim, Kenneth Wong, Konnie Urban. Generation of invasive breast cancer cell lines for in vivo imaging. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3908. doi:10.1158/1538-7445.AM2013-3908