Fibroblast growth factor-9 (glia-activating factor) stimulates proliferation and production of glial fibrillary acidic protein in human gliomas either in the presence or in the absence of the endogenous growth factor expression

Fibroblast Growth Factor Family in the Progression of Prostate Cancer

Fibroblast growth factors (FGFs) and FGF receptors (FGFRs) play an important role in the maintenance of tissue homeostasis and the development and differentiation of prostate tissue through epithelial-stromal interactions. Aberrations of this signaling are linked to the development and progression of prostate cancer (PCa). The FGF family includes two subfamilies, paracrine FGFs and endocrine FGFs. Paracrine FGFs directly bind the extracellular domain of FGFRs and act as a growth factor through the activation of tyrosine kinase signaling. Endocrine FGFs have a low affinity of heparin/heparan sulfate and are easy to circulate in serum. Their biological function is exerted as both a growth factor binding FGFRs with co-receptors and as an endocrine molecule. Many studies have demonstrated the significance of these FGFs and FGFRs in the development and progression of PCa. Herein, we discuss the current knowledge regarding the role of FGFs and FGFRs—including paracrine FGFs, endocrine FGFs, and FGFRs—in the development and progression of PCa, focusing on the representative molecules in each subfamily.

Identification of proteins secreted from leptin stimulated MCF-7 breast cancer cells: a dual proteomic approach

Leptin is an adipocyte-derived hormone that regulates energy expenditure and food intake. A significant role for leptin in breast cancer has also been indicated by the resistance of leptin knockout mice in development of mammary tumors. In vitro, leptin induces proliferation of MCF-7 cells by activating cellular signaling pathways (1, 11, 12, 16, 17, 56). As leptin is emerging as an important factor for tumor growth, and hormones can exert their actions via autocrine/paracrine mechanisms, we hypothesized leptin may act by regulating epithelial-derived proteins. To test this hypothesis, leptin-regulated proteins secreted from MCF-7 mammary tumor cells were identified using proteomics techniques. Treatment of MCF-7 cells with 500 ng/ml leptin for 24 hours resulted in a 40% increase in cell number and a 5-fold increase in protein secretion as compared to controls. Establishing the significance of leptin-induced secreted factors, the addition of conditioned media from leptin-treated MCF-7 cells to synchronized MCF-7 cells resulted in 40% increase in cell number. Identification of leptin-regulated secreted proteins was done by 2D gel electrophoresis coupled with MALDI-TOF mass spectrometry. Proteins identified using Pro Found software and NCBI database included KF10 Collagen Precursor, Serologically Defined Breast Cancer Antigen NY-BR-62 and Cortactin Isoform a. A Human Cytokine Antibody Array system was used to identify low abundant proteins in the media of control and 500 ng/ml leptin-stimulated MCF-7 cells. In leptin treated cells, levels of FGF-9 were increased while IGFBP-3 and TGF-beta3 levels were decreased. Many previous studies have focused on the regulation of distinct cellular proteins by leptin during mammary tumor cell proliferation. However, ours is the first study to identify leptin-regulated secreted proteins, many of which are known to play important roles in cancer. Our data support that leptin can influence mammary tumor growth and progression through regulation of autocrine/paracrine factors and by modulating the extracellular matrix composition.