Real Time Metastatic Route Tracking of Orthotopic PC-3-GFP Human Prostate Cancer Using Intravital Imaging.

The cellular basis of metastasis is poorly understood. An important step to understanding this process is to be able to visualize the routes by which cancer cells migrate from the primary tumor to various distant sites to eventually form metastasis. Our laboratory previously developed single-cell in vivo imaging using fluorescent proteins to label cancer cells. In the present study, using PC-3 human prostate cancer cells labeled with green fluorescent protein (GFP) and orthotopic tumor transplantation, we have imaged in live mice various highly diverse routes by which PC-3 cells metastasize superiorly and inferiorly to distant sites, including in the portal area, stomach area, and urogenital system. Imaging began at day 9, at which time distant metastasis had already occurred, and increased at each imaging point at days 10, 13, 14, and 16. Metastatic cells were observed migrating superiorly and inferiorly from the primary tumor as well as in lymphatic channels and trafficking in various organ systems demonstrating that PC-3 has multiple metastatic routes similar to hormone-independent advanced-stage prostate cancer in the clinic.