Showing papers on "Hepatocyte growth factor published in 1987"

Scatter factor is a fibroblast-derived modulator of epithelial cell mobility.

Abstract: Various factors are known to regulate cell growth and differentiation, but less is known of agents which affect movement and positioning, particularly in epithelial-mesenchymal interactions. Cultured human embryo fibroblasts release a protein with a relative molecular mass (Mr) of approximately 50,000 (50K) that affects epithelial cells by causing a disruption of junctions, an increase in local motility and a scattering of contiguous sheets of cells. To investigate specificity, a range of cells has been examined for the ability to produce the factor and for sensitivity to its action. Most freshly isolated normal epithelia and epithelia from cell lines of normal tissue, but not epithelia from tumour cell lines or fibroblasts, were sensitive to scatter factor. In contrast, production of the factor, as identified by activity and by chromatography, was restricted to embryonic fibroblasts and certain variants of 3T3 and BHK21 cells and their transformed derivatives. We conclude that the scatter factor is a paracrine effector of epithelial-mesenchymal interaction, which affects the intercellular connections and mobility of normal epithelial cells. The factor might be involved in epithelial migration, such as occurs in embryogenesis or wound healing.

Hepatocyte growth factor

Abstract: A hepatocyte growth factor comprising a proteinous substance derived from human blood and showing the following physicochemical properties and physiologic activity: (i) its molecular weight is estimated to be approximately 76,000 to 92,00 by SDS-PAGE analysis (under non-reductive conditon); (ii) it possesses HGF activity; (iii) the HGF activity is inactivated by heat treatment for 10 minutes at 80° C.; (iv) the HGF activity may be lost by digestion with trypsin or with chymotrypsin; and (v) it has a high affinity for heparin.

The function of metallothionein in cell metabolism.

Abstract: Rat hepatocytes were obtained and cultured in media containing 65Zn in the presence or absence of insulin and hepatocyte growth factors. Cells were also grown in a pulse-chase type of experiment. After varying periods of incubation the cells were harvested and assayed for zinc, protein and metallothionein. Although the amount of intracellular zinc (Zn/cell protein) was constant, the amount of metallothionein (MT/cell protein) in the cells exposed to zinc alone increased to a level approximately five times higher than the cells cultured in the presence of the growth factors. Chromatographs established that for cell cultured in the absence of hepatocyte growth factors all the 65Zn coeluted with metallothionein whereas for cultures maintained in the presence of these factors the zinc was associated with higher molecular weight components in addition to being present in the 10000 dalton peak.

Isolation of an autocrine growth factor from hepatoma HTC‐SR cells

Abstract: Growth of mammalian cells seems to be regulated to a large extent by hormones and growth factors which are present in serum, as well as in other tissue fluids. In addition, there seem to be growth inhibitors in various tissue fluids contributing to the complexity of the regulatory process (O’Keefe and Pledger, 1983; Moses et al., 1985). Some of the growth factors are produced by specific tissues or cells in the organism and might affect a variety of cells throughout the organism. Others seem to be produced by the same cells that are also responsive to them (Kaplan et al., 1982; Sporn and Todaro, 1980; Sporn and Roberts, 1985). Several excellent review articles have discussed many of the various growth factors and their properties (O’Keefe and Pledger, 1983; Moses et al., 1985; Holley, 1974; Antoniades and Owen, 1982; Goustin et al., 1986; Ciba Symposium, 1985). It has been known for some time that malignant cells seem to require fewer exogenous growth factors for optimal multiplication and growth than their cells of origin (Antoniades and Owen, 1982; Holley, 1975). Primarily by comparing 3T3 cells and virally transformed 3T3 cells in culture, it was shown that different serum concentrations and possibly different serum components were required to maintain and grow these cells (Holley, 1974; Antoniades and Owen, 1982; Holley, 1975). In general, much lower serum concentrations were needed to grow the virally transformed cells as well as other tumor cell lines (Antoniades and Owen, 1982). In recent years, an explanation for this self-sufficiency of malignant cells has emerged. It has been suggested that malignant cells can produce growth which act on their producer cells via external receptors (Kaplan et al., 1982; Sporn and Todaro, 1980; Burk, 1973; Todaro et al., 1976). This process is now referred to as “autocrine secretion” and provides an explanation for the ability of oncogenes to make cancer cells autonomous of exogenous growth factors (Sporn and Todaro, 1980; Sporn and Roberts, 1985). Some of the first evidence for endogenous growth factors in tumor cells was provided with murine sarcoma virus transformed Cells (Ozanne et al., 1980; DeLarco and Todaro, 1978). It was subsequently shown that these Sarcoma growth factors were structurally related to, but distinct from, epidermal growth factor (EGF). The EGF-like substances competed with authentic EGF for EGF receptors (Ozanne et al., 1980; Roberts et al., 1983). Soon, similar growth factors, now collectively referred to as transforming growth factors (TGF), were found in the conditioned medium of various cultured transformed cells (Sporn and Todaro, 1980; Ozanne et al., 1980; Roberts et al., 1980; Todaro et al., 1980). Two molecular species have been identified, a 25 kDa TGF-β and a 5.6 kDa TGF-α. These factors have also been isolated from mouse embryos (Proper et al., 1982). TGF-α has been demonstrated in human placenta (Stromberg et al., 1982) and in mouse embryo (Twardzik et al., 1982), and a platelet-derived TGF-β has been purified (Childs et al., 1982). Human cancer cells produce and release TGF and have functional receptors for the peptides (Todaro et al., 1980; Marquardt and Todaro, 1982; Halper and Moses, 1983; Richmond et al., 1983). We report the isolation and partial purification of a factor from rat hepatoma HTC-SR cells. This factor is produced by the HTC cells and stimulates DNA synthesis and growth specifically in these cells, thus meeting the criteria for an autocrine factor.