Fig. 1.

Increased HMW-FGF2 expression and signaling pathway activation in hormone-resistant compared to hormone-responsive tumors. a Immunohistochemistry and b WB of FGF2 in murine C4 tumor samples and human T47D-YA and T47D-YB xenografts. Bar: 40 μm; inset 15 μm. ERK was used as loading control. Immunoreactive bands were quantified and graphed relative to the hormone-responsive variant in each case. c, d Cell proliferation upon FGF2 treatment (1–100 ng/mL) measured by [³H]-thymidine uptake (c) or cell counting (d) in primary cultures of epithelial cells from the C4 family and T47D-YA and T47D-YB cells. e FGFR signaling was evaluated by WB analysis of pERK/ERK, PKCα/ERK, and pAKT/AKT in T47D-YA and T47D-YB whole-cell extracts with or without treatment with exogenous LMW-FGF2 (100 ng/mL; 10 min). Immunoreactive bands were quantified and graphed relative to the T47D-YA cell line or the untreated T47D-YA and T47D-YB cell lines. ERK was used as loading control. f WB analysis of PR and FGF2 in T47D-Y whole-cell extracts transfected with control (pSG5) or PRB plasmids. Immunoreactive bands were quantified and graphed relative to the T47D-Y-pSG5 cell line. ERK was used as loading control. The asterisks in e and f indicate the statistical significance of treated cells (+) vs. untreated cells (−). HMW, high molecular weight; LMW, low molecular weight