Vasohibin-2 promotes proliferation in human breast cancer cells via upregulation of fibroblast growth factor-2 and growth/differentiation factor-15 expression

Vasohibin-2 (VASH2) is an angiogenic factor, and has been previously reported to be a cancer-related gene, with cytoplasmic and karyotypic forms. In the current study VASH2 expression in human breast cancer tissue and adjacent non-cancerous tissue was investigated with immunohistochemistry. MCF-7 and BT474 human breast cancer cells were transfected with lentiviral constructs to generate in vitro VASH2 overexpression and knockdown models. In addition, BALB/cA nude mice were inoculated subcutaneously with transfected cells to generate in vivo models of VASH2 overexpression and knockdown. The effect of VASH2 on cell proliferation was investigated using a bromodeoxyuridine assay in vitro and immunohistochemistry of Ki67 in xenograft tumors. Growth factors were investigated using a human growth factor array, and certain factors were further confirmed by an immunoblot. The results indicated that the expression level of cytoplasmic VASH2 was higher in breast cancer tissues with a Ki67 (a proliferation marker) level of >= 14%, compared with tissues with a Ki67 level of <14%. VASH2 induced proliferation in vitro and in vivo. Four growth factors activated by VASH2 were identified as follows: Fibroblast growth factor 2 (FGF2), growth/differentiation factor-15 (GDF15), insulin-like growth factor-binding protein (IGFBP)3 and IGFBP6. FGF2 and GDF15 may contribute to VASH2-induced proliferation. The current study identified a novel role for VASH2 in human breast cancer, and this knowledge suggests that VASH2 may be a novel target in breast cancer treatment.