The location of acidic fibroblast growth factor in the breast is dependent on the activity of proteases present in breast cancer tissue

Chronic obstructive pulmonary disease is associated with enhanced bronchial expression of FGF-1, FGF-2, and FGFR-1

An important feature of chronic obstructive pulmonary disease (COPD) is airway remodelling, the molecular mechanisms of which are poorly understood. In this study, the role of fibroblast growth factors (FGF-1 and FGF-2) and their receptor, FGFR-1, was assessed in bronchial airway wall remodelling in patients with COPD (FEV1 < 75%; n = 15) and without COPD (FEV1 > 85%; n = 16). FGF-1 and FGFR-1 were immunolocalized in bronchial epithelium, airway smooth muscle (ASM), submucosal glandular epithelium, and vascular smooth muscle. Quantitative digital image analysis revealed increased cytoplasmic expression of FGF-2 in bronchial epithelium (0.35 +/- 0.03 vs 0.20 +/- 0.04, p < 0.008) and nuclear localization in ASM (p < 0.0001) in COPD patients compared with controls. Elevated levels of FGFR-1 in ASM (p < 0.005) and of FGF-1 (p < 0.04) and FGFR-1 (p < 0.001) in bronchial epithelium were observed. In cultured human ASM cells, FGF-1 and/or FGF-2 (10 ng/ml) induced cellular proliferation, as shown by [3H]thymidine incorporation and by cell number counts. Steady-state mRNA levels of FGFR-1 were elevated in human ASM cells treated with either FGF-1 or FGF-2. The increased bronchial expression of fibroblast growth factors and their receptor in patients with COPD, and the mitogenic response of human ASM cells to FGFs in vitro suggest a potential role for the FGF/FGFR-1 system in the remodelling of bronchial airways in COPD.

G388R mutation of the FGFR4 gene is not relevant to breast cancer prognosis

This study screened large cohorts of node-positive and node-negative breast cancer patients to determine whether the G388R mutation of the FGFR4 gene is a useful prognostic marker for breast cancer as reported by Bange et al in 2002. Node-positive (n=139) and node-negative (n=95) breast cancer cohorts selected for mutation screening were followed up for median periods of 89 and 87 months, respectively. PCR – RFLP analysis was modified to facilitate molecular screening. Curves for disease-free survival were plotted according to the Kaplan – Meier method, and a log-rank test was used for comparisons between groups. Three other nonparametric linear rank-tests particularly suitable for investigating possible relations between G388R mutation and early cancer progression were also used. Kaplan – Meier analysis based on any of the four nonparametric linear rank tests performed for node-positive and node-negative patients was not indicative of disease-free survival time. G388R mutation of the FGFR4 gene is not relevant for breast cancer prognosis.

Enhanced expression of fibroblast growth factors and receptor FGFR-1 during vascular remodeling in chronic obstructive pulmonary disease

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.

Fibroblast growth factor 8 is expressed at higher levels in lactating human breast and in breast cancer

Fibroblast growth factor 8 can transform NIH3T3 cells and its expression has been found to be associated with breast and prostate cancer. Following our finding that fibroblast growth factor 8 mRNA expression is increased in breast cancer, we have undertaken an immunohistochemistry study of fibroblast growth factor 8 expression in a series of human breast tissues and other normal tissues. Our findings confirm increased expression of fibroblast growth factor 8 in malignant breast tissue but also show significant fibroblast growth factor 8 expression in non-malignant breast epithelial cells. No significant difference in fibroblast growth factor 8 expression was found between different grades of ductal carcinoma, lobular carcinoma and ductal carcinoma in-situ or cancer of different oestrogen receptor, progesterone receptor or nodal status. The highest levels of fibroblast growth factor 8 expression were found in lactating breast tissues and fibroblast growth factor 8 was also detected in human milk. A survey of other normal tissues showed that fibroblast growth factor 8 is expressed in the proliferative cells of the dermis and epithelial cells in colon, ovary fallopian tube and uterus. Fibroblast growth factor 8 appears to be expressed in several organs in man and appears to have an importance in lactation.

Altered intracellular localization of fibroblast growth factor receptor 3 in human breast cancer

Immunohistochemical staining of human breast tissues, using an antibody against fibroblast growth factor receptor 3 [FGFR-3], showed differences in cellular distribution. Both malignant and non-malignant epithelial cells contained FGFR-3 immunoreactivity, but myoepithelial cells and stroma were negative. The staining pattern in malignant epithelial cells was predominantly nuclear, whereas epithelial cells in normal breast tissue showed both cytoplasmic and nuclear elements. Reverse transcription-polymerase chain reaction (RT-PCR) revealed two isoforms of FGFR-3 corresponding to the FGFR-3-IIIb variant and a previously described exon-deleted nuclear form of FGFR-3, which were present in both malignant and non-malignant epithelial cells. The higher level of nuclear staining and loss of cytoplasmic staining seen in malignant epithelial cells did not correspond to an increase in expression of the exon-deleted form of FGFR-3, nor to any detectable activating point mutations. Since receptor activation can result in its movement to a perinuclear localization, an alternative explanation for the redistribution of FGFR-3-IIIb could be different degrees of activation by a ligand (FGF1 or FGF9). No FGF9 was detected by immunohistochemistry in breast tissues. FGF1, however, is present in the majority of breast cancers and a different tissue distribution of FGF1 was found in breast tissues, showing predominantly nuclear, or a mix of nuclear and cytoplasmic FGFR-3. The difference in FGFR-3 staining patterns may implicate this ligand-receptor pair in breast cancer.

Clinical significance of determination of surrogate markers of angiogenesis in breast cancer

Compelling experimental and clinical data support the concept that breast carcinoma, as most of the other solid tumors, needs to develop the angiogenic phenotype for invasiveness, progression and metastasis. Several studies have determined intratumoral microvessel density by panendothelial markers and immunohistochemical techniques, with most of them showing that the degree of vascularity is associated with prognosis of the patients operated of early-stage invasive breast cancer. More recently, certain angiogenic peptides have been assessed in human breast cancer: vascular endothelial growth factor (VEGF), platelet derived-endothelial cell growth factor (PD-ECGF, also known as thymidine phosphorylase, TP) and fibroblast growth factor family (FGFs). Among these, the most studied is VEGF, which appears to be a powerful prognostic indicator. Little data are available on the clinical significance of naturally occurring antiangiogenic factors, with few studies reporting on interleukin-12 and thrombospondins. In vivo techniques for dynamic assessment of tumor blood network are presently under extensive research, in particular for monitoring activity of inhibitors of angiogenesis. The methods of assessment of angiogenic activity and the results of published clinical studies in peer reviewed Journals with a computerized overview of literature will be presented. Overall, the results of the reported studies suggest that human breast cancer is an angiogenic-dependent tumor for which antiangiogenic therapy represents a promising novel antitumoral therapeutic strategy.

Expression of acidic fibroblast growth factor (aFGF) and fibroblast growth factor receptor 4 (FGFR4) in breast fibroadenomas

BACKGROUND/AIM

Fibroadenomas are benign tumours composed of both glandular and fibrous tissue. The mechanisms regulating the growth of these tumours and the relation between the stromal and epithelial cells are poorly understood. Acidic fibroblast growth factor (aFGF) is a well known fibroblast activator, which acts through four specific cell surface receptors, among which, fibroblast growth factor receptor 4 (FGFR4) is highly specific. The aim of this study was to evaluate the distribution of aFGF and FGFR4 in specific cell types of fibroadenomas to understand their possible role in the growth of these breast lesions.

METHODS

Formalin fixed and paraffin wax embedded tissues from 15 fibroadenomas and peritumoral normal breasts were investigated for the expression of aFGF and FGFR4 using immunohistochemistry. The presence of aFGF mRNA was also investigated using in situ hybridisation.

RESULTS

Immunoreactivity for aFGF and FGFR4 was seen in epithelial cells, but it was lacking in myoepithelial cells of both normal tissues and fibroadenomas. Strong FGFR4 immunoreactivity was found in stromal fibroblasts, which were also weakly positive for aFGF. aFGF mRNA was detected in epithelial cells and in some stromal fibroblasts.

CONCLUSIONS

These results suggest a paracrine/autocrine modulation of epithelial and stromal cells of fibroadenomas through an aFGF-FGFR4 interaction. This interaction might regulate various cell functions and the growth of fibroadenomas.

Tyrosine kinase signalling in breast cancer: fibroblast growth factors and their receptors

The fibroblast growth factors [Fgfs (murine), FGFs (human)] constitute a large family of ligands that signal through a class of cell-surface tyrosine kinase receptors. Fgf signalling has been associated in vitro with cellular differentiation as well as mitogenic and motogenic responses. In vivo, Fgfs are critical for animal development, and some have potent angiogenic properties. Several Fgfs have been identified as oncogenes in murine mammary cancer, where their deregulation is associated with proviral insertions of the mouse mammary tumour virus (MMTV). Thus, in some mammary tumours of MMTV-infected mouse strains, integration of viral genomic DNA into the somatic DNA of mammary epithelial cells was found to have caused the inappropriate expression of members of this family of growth factors. Although examination of human breast cancers has shown an altered expression of FGFs or of their receptors in some tumours, their role in the causation of breast disease is unclear and remains controversial.

Upregulation of basic fibroblast growth factor in breast carcinoma and its relationship to vascular density, oestrogen receptor, epidermal growth factor receptor and survival

BACKGROUND

Angiogenesis, the process whereby endothelial cells divide and migrate to form new blood capillaries, has been assessed in tumours by measuring microvessel density. High microvessel density is a significant adverse prognostic factor in breast cancer. The angiogenic factor, basic fibroblast growth factor (bFGF), has been associated with tumourigenesis and metastasis in several human cancers. There are few quantitative studies of bFGF expression in normal tissues compared to cancer.

PATIENTS AND METHODS

We have measured bFGF levels in 149 human primary breast carcinomas and assessed the findings in relation to microvessel density, oestrogen receptor (ER) and epidermal growth factor receptor (EGFR). Basic FGF levels were measured by ELISA. Western blotting and immunohistochemistry were carried out to confirm the presence of bFGF.

RESULTS

Levels of bFGF were more than 10-fold higher in tumour cytosols compared to reduction mammoplasty tissue and 3-fold compared to non neoplastic cytosols from the same breast as the tumour (P < 0.0001). Immunohistochemistry showed bFGF protein was localised exclusively in the stroma whereas no bFGF staining was observed in the epithelial cells. High bFGF levels were significantly related to high ER (P = 0.01). Similarly, high bFGF levels were significantly related to low grade (P = 0.046) and to small tumour size (P = 0.04). No significant relationship was observed between bFGF and microvessel count, EGFR or age. In univariate analysis and in a Cox proportional hazard model bFGF did not reach significance for overall or relapse free survival.

CONCLUSIONS

Our results show that although bFGF is elevated in breast carcinomas compared to normal breast tissue it is not related to microvessel density and it is not an independent predictor of survival in breast cancer patients. Basic FGF may be one of multiple factors that synergise with other growth factors such as VEGF to enhance angiogenesis.

Cytokine-regulated urokinase-type-plasminogen-activator (uPA) production by human breast fibroblasts in vitro

It has been shown that, in breast stroma, urokinase-type plasminogen activator (uPA) mRNA is predominantly expressed by myofibroblasts located at the invasive areas of the tumor. To examine which factors present in a tumor environment are candidates responsible for the induction of these uPA-producing myofibroblasts, we studied in vitro the capacity of a paired panel of normal and tumor-derived human breast fibroblasts to produce uPA protein and the myofibroblast marker alpha-smooth-muscle-actin (alpha-SMA) in response to various cytokines implicated in the process of tissue-remodeling during malignant transformation. We found that fibroblasts produced increased amounts of uPA protein after exposure to a-FGF, b-FGF, EGF, PDGF-BB, and IFN-gamma, were unaffected in this respect by IL-6, M-CSF, GM-CSF and Oncostatin M, and produced decreased amounts of uPA protein after exposure to IL-1alpha, TNF-alpha, IGF-I, and IGF-II. None of these cytokines were able to induce a striking increase in the fraction of alpha-SMA-positive fibroblasts. On the other hand, 25 pM TGFbeta1 increased the fraction of alpha-SMA-positive fibroblasts 5-fold in both normal and tumor-tissue-derived fibroblasts. Nonetheless, the normal-derived fibroblasts were unaffected in their uPA-producing capacity by TGFbeta1, and the tumor-derived fibroblasts produced decreased amounts of uPA protein after exposure to this cytokine, implying that at least in vitro the myofibroblast phenotype is not a prerequisite for the production of uPA by human breast fibroblasts. In addition, we established that the basal-uPA-production of both normal and tumor-derived fibroblasts was increased by autocrinely produced b-FGF-like activity, and that the basal-uPA-production of at least the normal-derived fibroblasts was decreased by autocrinely produced IGF-like activity. Altogether, our data suggest an active role for fibroblasts in the process of uPA-directed breast tumor proteolysis.

Clinical significance of angiogenic factors in breast cancer

Growth, progression, and metastasis of breast cancer, as well as of most of the other tumors, are angiogenesis-dependent processes. Several pro-angiogenic growth factors and endogenous inhibitors of angiogenesis have been identified and sequenced, and experimental studies suggest that angiogenic activity of a tumor may result from downregulation of inhibitors of angiogenesis or up-regulation of endothelial growth factors. The mechanisms leading to the alteration of the balance between positive and negative modulators of angiogenesis are only partially known. We are at the beginning of research to identify the more active angiogenic factors in human breast cancer, and little information is presently available on their clinical significance. Preliminary results suggest that among the known angiogenic peptides, both vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor / thymidine phosphorylase (PD-ECGF/TP) have promising prognostic and, perhaps, predictive value. No data are available on the clinical value of co-determination of positive and negative regulators of angiogenesis to look at the angiogenic balance of each single tumor. Only a few studies have assessed the role of endogenous inhibitors of angiogenesis in human breast cancer, with results available only on thrombospondin-1 and -2 (TSP-1, -2). Finally, the determination of some integrins such as alpha6 and alphavbeta3 and of some other endothelial-adhesion molecules seems to be of potential prognostic value. Recognizing which are the more biologically active positive and negative angiogenic factors is the key for the identification not only of new prognostic markers but also of targets for antiangiogenic therapy in human breast cancer.

The human mammary gland basement membrane is integral to the polarity of luminal epithelial cells

We show that myoepithelial cell basement membrane derived E3 and E8 domains of laminin-1 are capable of polarizing luminal epithelial cells with regard to epithelial membrane antigen localization. This event is dependent on the alpha6 integrin and results in aggregation and phosphorylation of the tyrosine residues of the focal adhesion kinase complex. We also demonstrate that uncultured normal luminal epithelial cells synthesize normal levels of beta and gamma laminin chains and reduced levels of alpha chains mRNA in common with malignant epithelial cells. In contrast normal myoepithelial cells synthesize all three constituent chains of laminin-1. Therefore in breast cancer the absence of myoepithelial cells could result in a lack of laminin alpha chains which may contribute to loss of polarity of malignant epithelial cells.

Increased expression of fibroblast growth factor 8 in human breast cancer

Fibroblast growth factor 8 (FGF8) is an important developmental protein which is oncogenic and able to cooperate with wnt-1 to produce mouse mammary carcinoma. The level of expression of FGF8 mRNA was measured in 68 breast cancers and 24 non-malignant breast tissues. Elevated levels of FGF8 mRNA were found in malignant compared to non-malignant breast tissues with significantly more malignant tissues expressing FGF8 (P=0.019) at significantly higher levels (P=0.031). In situ hybridization of breast cancer tissues and analysis of purified populations of normal epithelial cells and breast cancer cell lines showed that malignant epithelial cells expressed FGF8 mRNA at high levels compared to non-malignant epithelial and myoepithelial cells and fibroblasts. Although two of the receptors which FGF8 binds to (FGFR2-IIIc, FGFR3-IIIc) are not expressed in breast cancer cells, an autocrine activation loop is possible since expression of fibroblast growth factor receptor (FGFR) 4 and FGFR1 are retained in malignant epithelial cells. This is the first member of the FGF family to have increased expression in breast cancer and a potential autocrine role in its progression.