Cytotoxic activity of recombinant bFGF-rViscumin fusion proteins

Cytotoxicity of a Novel Fibroblast Growth Factor Receptor Targeted Immunotoxin on a Human Ovarian Teratocarcinoma Cell Line

Basic fibroblast growth factor (bFGF) is an important tumor-associated growth factor that contributes to proliferation and angiogenesis of tumor. The high-affinity receptor for bFGF, fibroblast growth factor receptor (FGFR), is found to be overexpressed in a number of tumor cells. For the purpose of exploring the significance of bFGF/FGFR in tumor-targeted therapy, a recombinant immunotoxin contained the N-terminal 389 residues of diphtheria toxin (DT), and the full length of human bFGF was designed, expressed, and purified. The bioactivity of the product was evaluated by testing the cytotoxicity on PA-1 cells (a human ovarian teratocarcinoma cell line with high-level expression of FGFR) in vitro. The immunotoxin showed a significant cytotoxicity on PA-1 cells (IC(50) 8 - 9 ng/mL), and this effect could be antagonized by equine diphtheria antitoxin (DAT), bFGF, anti-bFGF monoclonal antibody (MAb), and anti- FGFR polyclonal antibody (PAb), respectively. Additionally, Chinese hamster ovary (CHO) cells and Hep-2 cells (a human epidermoid laryngocarcinoma cell line) with low expression of FGFR were tested to be resistant to the immunotoxin. The results indicated that FGFR might be an effective target for tumor therapy, and bFGF-mediated immunotoxin could be a potential candidate in the treatment of cancer.

Fibroblast growth factors in cancer: therapeutic possibilities

The fibroblast growth factor (FGF) family of signalling molecules and its receptors (FGFRs) contribute to normal developmental and physiological processes. However, the subversion of this powerful growth stimulatory pathway has been implicated in the generation of a variety of pathological conditions. This review focuses on the role of FGF/FGFRs in cancer. The case will be made that this signalling pathway is associated with and functionally important for the growth of some human tumours. As such, FGF/FGFRs can be viewed as rational therapeutic oncology targets and strategies used to inhibit these molecules are discussed. The therapeutic exploitation of tumour-associated FGFR expression to deliver toxins or antiproliferative signals to tumour cells is also reviewed, as is the use of FGFs as protein therapeutics to alleviate the side effects of cancer therapy.

Mistletoe lectin synergizes with paclitaxel in human SK-hep1 hepatocarcinoma cells

The effect of mistletoe lectin I (ML-I), an inhibitor of ribosomal protein synthesis, on the in vitro cytotoxicity of a clinically important anticancer drug, paclitaxel, was studied on cultured human hepatocarcinoma SK-Hep1 cells using the microculture tetrazolium test. The interaction between these two agents was analyzed for true synergism using the ED50 isobologram. Synergism was observed in the simultaneous treatment of the cells with ML-I in combination with paclitaxel. In addition, 24-h exposure of the cells to a non-toxic dose of ML-I and lower toxic doses of paclitaxel in combination resulted in apoptotic cell death, as observed by agarose-gel electrophoresis of low-molecular-weight DNA and DNA flow cytometry. Thus, the results presented here indicate the potential clinical usefulness of ML-I combination therapy with paclitaxel.