Hypoxia-stimulated expression of angiogenic growth factors in cervical cancer cells and cervical cancer-derived fibroblasts.

It is generally accepted that local growth of solid tumors and their ability to establish distant metastases are dependent on the formation of new blood vessels arising from preexisting ones (angiogenesis). The angiogenic response of the host is mediated by angiogenic molecules that are released from cancer and normal stroma cells, especially fibroblasts. The goal of the present study was to quantitatively compare the expression of the two most important angiogenic growth factors (VEGF, angiogenin) of cervical cancer cells (HeLa and Me-180) with that of cervical cancer-derived fibroblasts (from one tumor/patient) under defined normoxic and hypoxic conditions in vitro. The growth kinetics of cervical cancer cells (HeLa and Me-180) and tumor-derived fibroblasts were evaluated in vitro under normoxic and hypoxic conditions. Growth factor concentrations in the cell culture medium were measured by ELISA and the secretion rates per cell were calculated. Under normoxic conditions, both the cervical cancer cells as well as the tumor-derived fibroblasts released VEGF and angiogenin. The secretion rate of both angiogenic factors was significantly higher in the stroma cells than in the tumor cells (P < 0.05). VEGF and angiogenin secretion is significantly higher in the stroma cells under hypoxia than in the tumor cells investigated (P < 0.05). The presented data support the concept that in cervical cancer non-neoplastic fibroblasts could play a pivotal role in the complex process of tumor angiogenesis.