Proteomic and transcriptomic characterisation of FIA10, a novel murine leukemic cell line that metastasizes into the brain.

Brain metastasis leads to increased mortality and is a major site of relapse for several cancers, yet the molecular mechanisms of brain metastasis are not well understood. In this study, we established and characterized a new leukemic cell line, FIA10, that metastasizes into the central nervous system (CNS) following injection into the tail vein of syngeneic mice. Mice injected with FIA10 cells developed neurological symptoms such as loss of balance, tremor, ataxic gait and seizures, leading to death within 3 months. Histopathology coupled with PCR analysis clearly showed infiltration of leukemic FIA10 cells into the brain parenchyma of diseased mice, with little involvement of bone marrow, peripheral blood and other organs. To define pathways that contribute to CNS metastasis, global transcriptome and proteome analysis was performed on FIA10 cells and compared with that of the parental stem cell line FDCP-Mix and the related FIA18 cells, which give rise to myeloid leukemia without CNS involvement. 188 expressed genes (RNA level) and 189 proteins were upregulated (log2 ratio FIA10/FIA18 ≥ 1) and 120 mRNAs and 177 proteins were downregulated (log2 ratio FIA10/FIA18 ≤ 1) in FIA10 cells compared with FIA18 cells. Major upregulated pathways in FIA10 cells revealed by biofunctional analyses involved immune response components, adhesion molecules and enzymes implicated in extracellular matrix remodeling, opening and crossing the blood-brain barrier (BBB), molecules supporting migration within the brain parenchyma, alterations in metabolism necessary for growth within the brain microenvironment, and regulators for these functions. Downregulated RNA and protein included several tumor suppressors and DNA repair enzymes. In line with the function of FIA10 cells to specifically infiltrate the brain, FIA10 cells have acquired a phenotype that permits crossing the BBB and adapting to the brain microenvironment thereby escaping immune surveillance. These data and our model system FIA10 will be valuable resources to study the occurrence of brain metastases and may help in the development of potential therapies against brain invasion.

CVS-3983, a selective matriptase inhibitor, suppresses the growth of androgen independent prostate tumor xenografts.

BACKGROUND: Matriptase, a type-II transmembrane serine protease, is expressed by cancers of epithelial origin including breast, colon, and prostate carcinomas and has been implicated in tumor growth and progression. We studied the effects of CVS-3983, a selective small molecule matriptase inhibitor, on the growth of the androgen independent (AI) CWR22R and CWRSA6 human prostate cancer xenograft models. METHODS: CVS-3983 was administered i.p. twice-daily 7-days per week for 2-3 weeks to mice with established tumors. Measurements of tumor volume were made twice weekly. The effect of CVS-3983 on CWR22RV1 cell invasion through a reconstituted basement membrane matrix of proteins was also evaluated. Matriptase expression across the tumor lines was assessed by RT-PCR and Western blotting. RESULTS: CVS-3983 inhibited final mean tumor volume by 65.5% (n = 10, P = 0.0002) in the CWR22R model and by 56.2% (n = 8, P = 0.0017) in the CWRSA6 tumor model compared with vehicle-treated tumors. CVS-3983 did not inhibit the proliferation of CWR22RV1 cells in vitro; however, the small molecule did significantly reduce by 30.2% the invasion of these cells in vitro through a reconstituted basement membrane matrix. Molecular analysis of the xenograft tumors demonstrated high expression levels of matriptase at the RNA and protein levels, which were not affected by CVS-3983 treatment. CONCLUSIONS: These results identify CVS-3983 as a potent inhibitor of AI prostate cancer cell invasion in vitro and established xenograft tumor growth in vivo.