Expression and functional activity of fibroblast growth factors and their receptors in human pancreatic cancer.
We have analysed expression of the first 7 members of the family of heparin-binding fibroblast growth factor (FGFs) and their 4 high-affinity receptors (FGFRs) in human pancreatic carcinoma cell lines, both at the mRNA and protein levels. In cell lines expressing FGFRs, 2 typical patterns were observed: (i) expression of FGFR-I, -3 or -4 along with the expression of at least one FGF; (ii) co-expression of FGFR-3 and FGFR-4 in the absence of FGF expression. Using RT-PCR, transcripts representing multiple isoforms of both extracellular and intracellular domains of FGFR-I were detected in the cell line PT45. A novel extracellular domain variant of FGFR-I was predicted to encode the first immunoglobulin loop in a potentially secreted form. Protein expression of the splice variants of FGFR-I was confirmed by immunoprecipitation with specific antibodies in radiolabelled ligand cross-linking experiments. The type I carboxyl end and the alpha subtype extracellular domain were detected in the PANC-I cell line, while the type I carboxyl terminus and the gamma subtype extracellular domain were expressed in the PT45 cell line. Expression of FGF-2 in PT45 was also detected by immunoprecipitation using 3 different anti-FGF-2 antibodies. Apart from the 18-kDa product, higher molecular weight isoforms, namely 22- and 23-kDa isoforms, were expressed. In an assay of anchorage-independent growth, exogenous FGF-2 stimulated a maximum 15-fold and 10-fold increase in colony formation by the cell lines MIA PACA-2 and PANC-I respectively. Treatment of monolayer cultures of the same cell lines did not promote growth. However, a specific neutralising antibody against FGF-2 reduced cell proliferation of MIA PACA-2 cells by 50%.
Leung
H Y
HY
Imperial Cancer Research Fund Oncology Unit, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Gullick
W J
WJ
Lemoine
N R
NR
D001483:Base Sequence; D002455:Cell Division; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D014644:Genetic Variation; D006801:Humans; D007163:Immunosorbent Techniques; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D012326:RNA Splicing; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000502:physiology*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D005346:Fibroblast Growth Factors