A Novel Near-infrared Fluorescent Protein, iRFP720, Facilitates Transcriptional Profiling of Prostate Cancer Bone Metastasis in Mice.

BACKGROUND: Bone represents a frequent site of prostate cancer metastasis. As the molecular mechanism remains unclear, an accessible animal model is required. MATERIALS AND METHODS: We established a novel murine metastasis model using near-infrared fluorescent protein iRFP720-labelled prostate cancer (PC3) cells. To clarify transcriptional alterations during metastasis, iRFP720-PC3 cells were intracardially injected into male mice. mRNA expression profiles of metastasis in bone using marrow cancer cells extracted by centrifugal separation and cell sorting were compared with those of parental cells by microarray. Differentially expressed genes were analyzed by pathway analysis. RESULTS: We identified 327 and 197 genes being up- and down-regulated, respectively. Pathway analysis revealed that the p53 signaling pathway, extracellular matrix receptor interaction, Mammalian target of rapamycin signaling pathway, cancer-related pathways, small cell lung cancer, and Escherichia coli infection response were altered. CONCLUSION: iRFP720 is useful for in vivo cell detection/isolation. The results of expression analysis may improve prostate cancer treatment strategies.