Important characteristics of chronic obstructive pulmonary disease (COPD) include airway and vascular remodeling, the molecular mechanisms of which are poorly understood. We assessed the role of fibroblast growth factors (FGF) in pulmonary vascular remodeling by examining the expression pattern of FGF-1, FGF-2, and the FGF receptor (FGFR-1) in peripheral area of lung tissues from patients with COPD (FEV(1) < or = 75%; n = 15) and without COPD (FEV(1) > or = 85%; n = 13). Immunohistochemical staining results were evaluated by digital video image analysis as well as by manual scoring. FGF-1 and FGFR-1 were detected in vascular smooth muscle (VSM), airway smooth muscle, and airway epithelial cells. FGF-2 was localized in the cytoplasm of airway epithelium and in the nuclei of airway smooth muscle, VSM, and endothelial cells. In COPD cases, an unequivocal increase in FGF-2 expression was observed in VSM (3-fold, P = 0.001) and endothelium (2-fold, P = 0.007) of small pulmonary vessels with a luminal diameter under 200 micro m. In addition, FGFR-1 levels were elevated in the intima (1.5-fold, P = 0.05). VSM cells of large (> 200 micro m) pulmonary vessels showed increased staining for FGF-1 (1.6-fold, P < 0.03) and FGFR-1 (1.4-fold, P < 0.04) in COPD. Pulmonary vascular remodeling, assessed as the ratio of alpha-smooth muscle actin staining and vascular wall area with the lumen diameter, was increased in large vessels of patients with COPD (P = 0.007) and was inversely correlated with FEV(1) values (P < 0.007). Our results suggest an autocrine role of the FGF-FGFR-1 system in the pathogenesis of COPD-associated vascular remodeling.
Summary A variant form of the human oestrogen receptor (ER) mRNA lacking sequences encoded within exon 5 has been described (Fuqua SAW, Fitzgerald SD, Chamness GC, Tandon AK, McDonnell DP, Nawaz Z, O'Malloy BW, McGuire WL 1991, Cancer Res 51: 105-1 09).We have examined the expression of the exon 5-deleted ER (HEA5) mRNA variant in breast biopsies using reverse transcriptase polymerase chain reaction (RT -PCR). HEA5 mRNA was present in only 13% of non-malignant breast tissues compared with 32% of carcinomas (95% Cl, P=0.05). Presence of the HEA5 mRNA was associated with the presence of immunohistochemically detected ER (P=0.015) and progesterone receptor (PR) (P=0.02). There was a positive correlation between the presence of HEA5 and disease-free survival (P=0.05), suggesting that the presence of HEA5 may be an indicator of better prognosis. We have raised a monoclonal antibody specific to the C-terminal amino acids of HEA5. This antibody recognized the variant but not the wild-type ER protein. We show that HEA5 protein is present in breast cancer using immunohistochemical techniques. We also analysed trans-activation by HEA5 in mammalian cells and showed that, in MCF-7 cells, HEA5 competes with wild-type ER to inhibit ERE-dependent trans-activation. Our results indicate that this variant is unlikely to be responsible for endocrine resistance of breast cancer, but its presence at both the mRNA and protein level suggest that it may, nevertheless, be involved in regulating the expression of oestrogen-responsive genes in breast cancer.Keywords: breast neoplasm; exon; polymerase chain reaction; oestrogen receptor; transcription Two-thirds of human breast carcinomas are characterized by the presence of appreciable amounts of oestrogen receptor (ER) protein.A proportion of these tumours also contain progesterone receptor (PR) and it is generally accepted that ER regulates PR gene expression. The presence of ER is correlated with a better prognosis and ER+/PR+ tumours are much more likely to respond to endocrine therapy than ER-/PR-tumours. Interestingly, ER-/PR+ tumours are twice as likely to respond as ER+/PR-tumours. A significant proportion of ER+/PR+ tumours, however, fail to respond to endocrine therapy and those that do so eventually become resistant to such therapy. The mechanisms leading to endocrine resistance are not yet clear (for reviews see McGuire, 1978;McGuire et al, 1991;Fuqua, 1994;Horwitz, 1994;Sluyser, 1994).The human oestrogen receptor cDNA and its gene (Ponglikitmongkol et al, 1988) have been cloned and the molecular mechanisms by which it acts are well understood. Alignment of the predicted ER amino acid sequences from different species shows that it can be divided into six regions A to F on the basis of differing amino acid sequence homology . Functional studies have shown that region C encodes the DNA- Kumar et al, 1987). Regions A/B and E contain trans-activation functions 1 (AFI) and 2 (AF-2) respectively (Kumar et al, , 1987Webster et al, 1988; Lees et al, 1989; Tora et al, 1989a;Berry et ...
Summary Acidic fibroblast growth factor (FGF1) and two of its receptors, FGFR1 and FGFR4, were localized in cryostat sections of normal, benign and malignant human breast tissue by immunohistochemistry. Without pretreatment, FGF1 staining was mainly seen in normal epithelial cells. However, polymerase chain reaction (PCR) analysis and immunoblotting of isolated normal epithelial and myoepithelial cells showed FGF1 mRNA and protein to be present in both cell types. Following incubation of frozen sections at 370C in phosphate-buffered saline, FGF1 staining was also revealed in myoepithelial cells and basement membrane adjacent to carcinoma cells. Treatment with protease inhibitors demonstrated that this effect was due to the activity of an endogenous protease. In contrast, FGF1 staining was found to be associated with the stroma adjacent to malignant cells only in the presence of protease inhibitors. FGFR1 and FGFR4 immunostaining was localized to both normal and malignant epithelial cells and to a lesser extent to myoepithelial cells. There was no difference in the staining intensity for the FGF receptors between normal and cancer samples. The change in location of FGF1 between normal and malignant tissues and the sensitivity of stored FGF1 to the action of endogenous proteases raises the possibility of both autocrine and paracrine roles for FGF1 in the normal and malignant human breast.Keywords: breast cancer; fibroblast growth factor 1; protease; immunohistochemistry Fibroblast growth factor 1 (FGF1) belongs to a family of multifunctional polypeptides that are involved in a wide array of biological processes, which include cellular proliferation and differentiation, angiogenesis, chemotaxis, embryonal development and tissue repair (Basilico and Moscatelli, 1992). To date, the FGFs consist of a family of nine homologous polypeptide growth factors that include FGF1 (acidic FGF), FGF2 (basic FGF), FGF3 (int-2), FGF4 (hst-l/Kaposi FGF), FGF5, FGF6 (hst-2), FGF7 (keratinocyte growth factor), FGF8 (androgen-induced growth factor) and FGF9 (glial-activating factor) (Basilico and Moscatelli, 1992;Tanaka et al, 1992;Miyamoto et al, 1993). These proteins share 35-50% overall homology of their amino acid sequences (Basilico and Moscatelli, 1992;Givol and Yayon, 1992).Unlike other members of the family, FGF1, FGF2 and FGF9 are synthesized without a signal peptide sequence and thus may remain sequestered in the cell (Basilico and Moscatelli, 1992;Cao and Pettersson, 1993). However, release of FGF may occur through leakage from damaged cells or from viable cells via a novel mechanism (Mignatti et al, 1992;Cao and Pettersson, 1993). Yeoman (1993) has postulated that proteoglycan-bound FGF may be released from the cell surface or extracellular matrix by the action of proteases, and Briozzo et al (1991) have shown that Received 10 June 1996 Revised 26 November 1996 Accepted 3 December 1996 Correspondence to: J Gomm MCF7 breast cancer cells secrete cathepsin D, which is able to digest the extracellular matrix and releas...
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