Vitamin D Binding Protein-Macrophage Activating Factor Inhibits HCC in SCID Mice.

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J Surg Res. 2010 Sep 18. [Epub ahead of print]

Vitamin D Binding Protein-Macrophage Activating Factor Inhibits HCC in SCID Mice.

Nonaka K, Onizuka S, Ishibashi H, Uto Y, Hori H, Nakayama T, Matsuura N, Kanematsu T, Fujioka H.

Clinical Research Center, National Hospital Organization Nagasaki Medical Center, Department of Hepatology, Nagasaki University Graduate School of Biomedical Sciences, Omura, Japan.


BACKGROUND: A high incidence of recurrence after treatment is the most serious problem in hepatocellular carcinoma (HCC). Therefore, a new strategy for the treatment of the disease is needed. The aim of the present study was to investigate whether vitamin D binding protein-macrophage activating factor (DBP-maf) is able to inhibit the growth of HCC.

METHODS: The effects of DBP-maf on endothelial cells and macrophage were evaluated by WST-1 assay and phagocytosis assay, respectively. Human HCC cells (HepG2) were implanted into the dorsum of severe combined immunodeficiency (SCID) mice. These mice were divided into control and DBP-maf treatment groups (n = 10/group). The mice in the treatment group received 40 ng/kg/d of DBP-maf for 21 d.

RESULTS: DBP-maf showed anti-proliferative activity against endothelial cells and also activated phagocytosis by macrophages. DBP-maf inhibited the growth of HCC cells (treatment group: 126 ± 18mm(3), untreated group: 1691.5 ± 546.9mm(3), P = 0.0077). Histologic examinations of the tumors revealed the microvessel density was reduced and more macrophage infiltration was demonstrated in the tumor of mice in the treatment group.

CONCLUSION: DBP-maf has at least two novel functions, namely, an anti-angiogenic activity and tumor killing activity through the activation of macrophages. DBP-maf may therefore represent a new strategy for the treatment of HCC.