Granulocyte colony-stimulating factor may promote proliferation of human bladder cancer cells mediated by basic fibroblast growth factor.

ABSTRACT

OBJECTIVES: To investigate whether granulocyte colony-stimulating factor (G-CSF) promotes the proliferation of two bladder cancer cell lines, and to assess the mechanism of tumor proliferation in terms of cytokine expression. MATERIAL AND METHODS: The proliferation of two bladder cancer cell lines derived from transitional cell carcinoma (KK-47 and T-24) was assessed by using the double-layer soft agarose colony assay in combination with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Seven cytokines were measured in the culture supernatant. Expression of granulocyte colony-stimulating factor (G-CSF) receptor and fibroblast growth factor (FGF) receptor mRNA was studied by means of reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Recombinant human G-CSF (rhG-CSF) caused greater induction of the proliferation of KK-47 cells in the presence than in the absence of peripheral blood mononuclear cells (PBMCs) and its effect was dose-dependent. In contrast, rhG-CSF did not stimulate the proliferation of T-24 cells. Among several cytokines measured, only basic FGF was elevated in cultures of KK-47 cells with or without PBMCs. The basic FGF level was significantly increased by rhG-CSF stimulation in a dose-dependent manner. Specific PCR products for the G-CSF and FGF receptors were observed in KK-47 cells as well as PBMC, while no G-CSF receptor was detected in T-24 cells. CONCLUSION: rhG-CSF may promote the proliferation of KK-47 cells, probably via an increase in basic FGF production.