title: Imaging and quantification of metastatic melanoma cells in lymph nodes with a ferritin MR reporter in living mice.
abstract: Cellular MRI with a reporter gene offers the opportunity to track small numbers of tumor cells and to study metastatic processes in their earliest developmental stages in the target organs of interest. This study demonstrates the feasibility of using the MR reporter ferritin for the noninvasive imaging and quantification of metastatic melanoma cells in the lymph nodes (LNs) of living mice. A B16F10 murine melanoma cell line expressing human ferritin heavy chain (hFTH) and green fluorescent protein (GFP) was constructed to allow the detection of cells by MRI and fluorescence imaging. Stable overexpression of hFTH and GFP in B16F10 murine melanoma cells was feasible and showed no cellular toxicity. In addition, hFTH cells were detectable by 9.4-T MRI in  vitro and in  vivo, yielding significant changes in T(2)* relative to control cells. In BALB/c nude mice, the presence of hFTH- and GFP-expressing metastatic melanoma cells in deep-seated axillary LNs was demonstrated as areas of low T(2)* on MRI, but the same LNs were not visible by fluorescence imaging because the light was unable to penetrate the tissue. Furthermore, the metastatic volume of each LN, which was assessed by cumulative histogram analysis of the T(2)* MRI data, correlated well with tumor burden, which was determined by histology (r = -0.8773, p = 0.0001). This study is the first to use MRI and an MR reporter gene for both the visualization and quantification of metastatic cancer cells in LNs.
authors: Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea.
authors: Seung Hong
authors: SH
authors: Choi
authors: Hye Rim
authors: HR
authors: Cho
authors: Hoe Suk
authors: HS
authors: Kim
authors: Young Hwa
authors: YH
authors: Kim
authors: Keon Wook
authors: KW
authors: Kang
authors: Hyeonjin
authors: H
authors: Kim
authors: Woo Kyung
authors: WK
authors: Moon
mesh_terms: D000818:Animals; D001052:Apoferritins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D045744:Cell Line, Tumor; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008856:Microscopy, Fluorescence / Q000379:methods; D014162:Transfection
chemical_list: D049452:Green Fluorescent Proteins; D001052:Apoferritins