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Biomedical subjects

M Bano

Publications and source records attributed to M Bano.

At least 19 recordsLinked to original sources
PubMed1992

Receptor-induced phosphorylation by mammary-derived growth factor 1 in mammary epithelial cell lines.

Previous work has shown that a mammary-derived growth factor (MDGF1), a human milk-derived, acidic, 62-kDa, N-glycosylated growth factor binds to cell surface receptors and stimulates proliferation of mammary epithelial cells. An 18-amino acid N-terminal partial sequence of the factor did not show any homology to other known growth factors or proteins. Using polyclonal antiserum raised against the synthetic peptide, we demonstrated that conditioned medium prepared from human breast cancer cell lines contains the factor. The antibody could adsorb the biological activity of the factor present in the conditioned medium. Earlier experiments on receptor cross-linking indicated that the receptor was approximately 120-140 kDa. Since tyrosine phosphorylation plays a crucial role in cell proliferation and cell transformation, experiments were conducted to find out whether MDGF1 induces the appearance of phosphotyrosine in MDGF1-receptor-positive MDA-MB 468, MCF-7, and 184A1N4 cell lines compared to receptor-negative lines. Western blot analysis using monoclonal antiphosphotyrosine indicated that MDGF1 induces phosphotyrosine in a 180-185-kDa protein in MDGF1 receptor-positive cell lines. Phosphorylation was not blocked and phosphorylated proteins were not immunoprecipitated by an antibody directed against the binding site of the EGF receptor. Cell membrane fractionation demonstrated that phosphorylation induced by MDGF1 was membrane-associated. The nature of this 180-185-kDa protein and its possible relationship to the MDGF1 receptor are under investigation.

Blotting, Western↗
PubMed1992

Production and characterization of mammary-derived growth factor 1 in mammary epithelial cell lines.

A mammary-derived growth factor, MDGF1, which stimulates collagen synthesis and proliferation in mammary epithelial cells was previously detected and purified from human milk and primary human breast tumors. MDGF1 binds to putative cell-surface receptors of 120-140 kDa and stimulates proliferation of normal and malignant human mammary epithelial cells. Partial protein sequence (N-terminal 18 amino acid sequence) shows that MDGF1 has no homology to any other known growth-promoting peptides. Polyclonal antiserum raised against this synthetic peptide recognizes native milk-derived MDGF1. We hypothesize that MDGF1 might be an autocrine or paracrine factor produced by and acting on normal and malignant human breast epithelial cells possessing MDGF1 receptors. As a first step in testing this possibility, we examined whether human breast epithelial cells in culture produce the growth factor. A protein with the size of MDGF1 was immunologically detected in the concentrated conditioned medium prepared from human breast cancer cell line MDA-MB 231, the mammary-derived but nontumorigenic HBL-100 line, and the normal reduction mammoplasty-derived, nonimmortalized 184 cell strain. A competitive radioreceptor assay (RRA) was used to estimate the level of MDGF1 in the conditioned medium. MDGF1 was present in the nanogram range per 1 million cells. A 62-kDa protein was detected in the above cell lysates by Western immunoblotting or by immunoprecipitation of metabolically labeled cell-conditioned media. The polyclonal antisera directed against the 18 amino acid peptide sequence from milk-derived MDGF1 could adsorb MDGF1 biological activity from conditioned medium. In vitro translation of cell mRNA yielded a protein of 55 kDa which was immunoprecipitated by anti-MDGF1 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Growth factors in breast cancer: mitogenesis to transformation.

While endocrine steroid hormones have been known for many years to regulate normal and malignant mammary epithelium, recent studies have led to an appreciation of polypeptide growth factors as locally-acting autocrine and paracrine effectors. In the current article we summarize what is known about growth factor regulation and action in the normal mammary gland and about perturbations of the steroid-growth factor interplay as cancer progresses. A major theme is that oncogenic activation modulates both regulation of production and function of growth factors in the mammary gland.

Animals↗
PubMed1991

Transforming growth factor beta 1 induces cachexia and systemic fibrosis without an antitumor effect in nude mice.

While stimulating the growth of fibroblasts, transforming growth factor beta 1 (TGF-beta 1) inhibits the growth of various normal and malignant cell lines in vitro. We studied the effects of TGF-beta 1 in vivo. The level of TGF-beta 1 in serum was maximally elevated 2 h after injecting 1 muCi of 125I-TGF-beta 1 into the peritoneal cavity of nude mice. Five h after the i.p. administration of 10 micrograms of unlabeled TGF-beta 1, 20 ng/ml of TGF-beta-like material in serum were detected by a radioreceptor assay on A549 lung carcinoma cells. Trichloracetic acid-precipitable 125I-TGF-beta 1 was taken up by liver, spleen, lungs, kidneys, and tumor tissue but not by the brain. At doses exceeding 2 micrograms/day, TGF-beta 1 induced a generalized interstitial fibrosis and a cachexia, which was not mediated by elevated serum levels of tumor necrosis factor alpha as determined by Western blot analysis and enzyme-linked immunosorbent assay. A total of 200,000 cells of the estrogen receptor-negative human breast cancer line MDA-MB-231, which had been shown to be maximally growth inhibited in vitro by 40 pM TGF-beta 1 and to have high-affinity receptors (9, 11, 12), were injected into the mammary fat pad of each nude mouse. The duration of treatment was 16 days with ten animals in the control group and five animals in the treated groups. The dose ranged from 1 to 4 micrograms per animal daily. The treatment was started 24 h after the injection of the tumor cells. Tumor growth was not significantly affected at either nontoxic or toxic doses of TGF-beta 1. Thus, we have demonstrated that TGF-beta 1, apart from being a local growth factor, has systemic effects, such as cachexia and multiple fibrosis. Its role as an antitumor agent may be limited.

Animals↗
PubMed1990

Characterization of mammary-derived growth factor 1 receptors and response in human mammary epithelial cell lines.

Mammary-derived growth factor 1 (MDGF1, with a molecular mass of 62 kDa and pI of 4.8) has been purified from human milk (Bano, M., Salomon, D. S., and Kidwell, W. R. (1985) J. Biol. Chem. 260, 5745-5752). N-terminal sequence of 18 amino acids showed no homology to any known growth promoting peptides. The present study was carried out to evaluate the biological effects of and binding sites for MDGF1 on normal human and breast cancer cell lines. At a concentration of 10-25 ng/ml the factor stimulated the growth of estrogen receptor-positive MCF-7 human breast cancer cells by 50% and also stimulated the synthesis of collagen IV by 40%. It did not have any effect on ZR75-1, T47-D, and MDA-MB 231 cells. The factor showed a biphasic effect on the estrogen receptor-negative MDA-MB 468 cells at concentrations above 5 ng/ml. The growth of normal human mammary epithelial cells (184 strain) was enhanced by 35%, whereas immortalized non-tumorigenic 184A1N4 human mammary epithelial cells were stimulated by about 60-70%. However, transformation of these cells by SV40-T, v-Ha-ras, or v-mos desensitized them to MDGF1. Iodinated MDGF1 binds to moderate affinity sites on the responsive MCF-7, MDA-MB 468, and 184A1N4 cell lines (KD = 6 x 10(-9) M). Cross-linking of 125I-MDGF1 to binding sites revealed the presence of a major band of molecular mass of approximately 180-200 kDa in MCF-7 and MDA-MB 468 cell lines. Labeling of this band was inhibited by excess unlabeled MDGF1. These data suggest that human mammary epithelial cell lines possess receptors for MDGF1.

Binding, Competitive↗
PubMed1989

Endocrine therapy of human breast cancer cells: the role of secreted polypeptide growth factors.

Endocrine therapy is an important modality in the treatment of breast cancer. However, the precise molecular mechanisms underlying the growth inhibitory effect of endocrine therapy are unknown. Recently, it has been shown that breast cancer cells express and secrete polypeptide growth factors that can regulate the growth of the cells through autocrine and/or paracrine pathways. These growth factors are thought to be involved in the response to endocrine therapy. Three different mechanisms have been suggested: (1) stimulation of growth inhibitory peptides; (2) repression of mitogenic peptides; and (3) stimulation of mitogenic growth factors in cells overexpressing the corresponding receptor. This article reviews the scientific evidence on which these hypotheses are based.

Breast Neoplasms↗
PubMed1986

Partial purification of transforming growth factors from human milk.

Crude, delipidated milk and the acid:ethanol extracts of primary human breast tumors contain several activities that biologically resemble transforming growth factors (TGFs) in that they promote the anchorage-independent growth of normal rat kidney and Mm5mt/c1 mouse mammary tumor cells in soft agar. Three major TGF species with isoelectric points (pl) of about 4.0, 6.0-6.5, and 7.0 have been detected in both tumors and milk. The pl 4.0 species from milk has been purified about 10,000-fold by isoelectric focusing and high-performance liquid chromatography. This species, designated milk-derived growth factor II (MDGFII), coelutes from gel filtration columns with an authentic human epidermal growth factor standard when using a low ionic strength eluting buffer. However, on the same column, MDGFII is completely resolved from human epidermal growth factor with high ionic strength eluting buffers. Nevertheless, MDGFII purified by the latter technique still competes with 125I-epidermal growth factor for receptor binding to A431 cell membranes. Additionally the TGF activity of MDGFII present in the pl 4.0 fraction of milk is markedly inhibited by anti-epidermal growth factor receptor antibody preparations. Consequently MDGFII appears to be an alpha-TGF. MDGFII is a pepsin-sensitive, disulfide reducing agent-sensitive, heat-stable protein that may be physiologically important for the mammary gland or the neonate.

Animals↗
PubMed1985

Purification of a mammary-derived growth factor from human milk and human mammary tumors.

A growth factor, mammary-derived growth factor 1 (MDGF1), has been purified to apparent homogeneity from human milk. The factor is a pepsin-sensitive, reducing agent-insensitive protein with a molecular mass of 62 kDa and a pI of 4.8. An apparently identical factor has been isolated from human mammary tumors, suggesting that MDGF1 might be made by and act as an autocrine growth factor for mammary cells. High affinity receptors for MDGF1 have been detected on mouse mammary cells, normal rat kidney cells, and A431 epidermoid cells (KD = 2 X 10(-10) M). MDGF1 at picomolar levels stimulates the growth of mammary cells and greatly amplifies their production of collagen, apparently via elevating collagen mRNA levels, an effect that is demonstrated for normal rat kidney cells. The responsiveness of mammary cells to MDGF1 is attenuated when the cells are grown on a basement membrane collagen substratum, a component of the extracellular matrix upon which these cells normally rest in vivo. MDGF1 thus may regulate the production of new basement membrane as mammary epithelium invades the stroma during proliferation.

Amino Acids↗
PubMed1985

HPLC method for determination of ergot alkaloids and some derivatives in human plasma.

Ergot alkaloids and their dihydrogenated methanesulphonate (ms) salts were determined and measured in human plasma. High-performance liquid chromatography (HPLC) with fluorometric detection was used for separation of ergot alkaloids in plasma. Several ergot alkaloids and their derivatives, including lysergide (LSD), can be identified in cases of poisoning.

Chromatography, High Pressure Liquid↗
PubMed1985

Interleukin 1 increases collagen type IV production by murine mammary epithelial cells.

The effects of human interleukin 1 (IL 1) on collagen type IV production by normal mouse mammary epithelial cells were examined. Human IL 1 was derived from the culture media of peripheral blood monocytes or placental cells that were stimulated with silica. Although crude culture media of silica-stimulated monocytes or placental cells had no enhancing activity for type IV collagen production, IL 1-containing fractions obtained by Sephacryl S-200 gel chromatography and isoelectrofocusing from such media possessed considerable activity. To confirm the effects of IL 1 on collagen production, human monocyte-derived IL 1 was highly purified by sequential isoelectrofocusing, anion-exchange (AX 300), high-performance liquid chromatography (HPLC), and HPLC gel filtration (TSK 3000). The same HPLC gel filtration fractions contained both an activity that stimulated collagen synthesis by mammary cells and thymocyte growth-promoting activity. These activities of IL 1 differed from a number of other factors, such as epidermal growth factor and another factor produced by placental cells that stimulated type IV collagen production but not thymocyte proliferation. In fact, IL 1 induced 100-fold less collagen type IV production by mammary epithelial cells than was needed to induce thymocyte proliferation. Our data suggest that IL 1-like molecules, which reportedly are produced by many tissue cell types, may therefore play a role in promoting a basement membrane formation at stromal-epithelial boundaries.

Animals↗
PubMed1984

Characterization of rat mammary tumor cell populations.

Nodules of tumor cells have been isolated from 7, 12-dimethylbenz (alpha)anthracene-induced rat mammary tumors. These nodules consist of at least two cell populations which can be subfractionated by selective attachment in calcium-free medium. One cell population which attaches in the absence of calcium (basal cells) stains intensively with antibodies against type IV collagen and also with antibodies against keratin. The nonattaching population, the epithelial cells, stains much more weakly with either antibody. Biochemical analyses indicate that 27% of the protein labeled in basal cell culture is type IV collagen, while 8% is keratin. With epithelial cells, only 0.35% of the protein made is collagen, and only 2.4% is keratin. Basal cells contain about 2 times as much calmodulin as epithelial cells but only about one-tenth as many estrogen receptors. In culture, the basal cells stimulate the attachment and/or division of the epithelial cell population. The epithelial cells have little effect on the division or attachment of the basal cells. Interaction between the two cell populations may be important for tumor growth in vivo.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Presence of transforming growth factors in human breast cancer cells.

Conditioned medium (CM) from a human mammary carcinoma cell line, MCF-7, and ten individual clones derived from these cells was examined for the presence of transforming growth factors (TGFs). Concentrated CM from all of the MCF-7 cell lines was found to stimulate the anchorage-independent growth of normal rat kidney cells in soft agar and to inhibit the binding of epidermal growth factor (EGF) to mouse NIH/3T3 fibroblasts and to A431 human epidermoid carcinoma cell membranes. The soft agar stimulating activity was heat stable but sensitive to treatment with dithiothreitol. EGF receptors were measured on the MCF-7 cell lines to determine whether the amount of TGFs associated with the CM from the various cell lines was correlated with the level of EGF receptors being expressed on these cells. Moreover, the intrinsic cloning efficiency of these lines in soft agar was measured to ascertain if any correlation might exist between the level of TGFs associated with these cells and the ability of these cell lines to form colonies in soft agar. Although all the MCF-7 cell lines had approximately the same number of EGF receptors per cell, ranging from 3 to 6 X 10(3) sites/cell, CM from these lines varied in potency with respect to inducing the growth of normal rat kidney cells as colonies in soft agar and in inhibiting the binding of EGF to NIH/3T3 cells. Likewise, the level of TGFs associated with the CM from the various clones showed no correlation with the ability of these individual lines to grow as colonies in soft agar. TGF activity was also detected in acid-ethanol extracts prepared from MCF-7 cells propagated in nude mice as tumors and in the extracts from two transplantable human mammary adenocarcinomas, Clouser I and II. In addition, approximately 50% of the normal rat kidney colonies formed in response to the Clouser II tumor extracts exhibited a branching morphology in contrast to spherical colonies produced by Clouser I or MCF-7 extracts. These results demonstrate that human mammary carcinoma cells from both established cell lines and cells maintained in nude mice as tumors contain TGF-like activities. Furthermore, the variation in TGFs associated with the CM from the MCF-7 clones suggests that the parent MCF-7 cell line contains a heterogeneous population of cells.

Animals↗
PubMed1983

Detection and partial characterization of collagen synthesis stimulating activities in rat mammary adenocarcinomas.

Rat mammary epithelium and adenocarcinomas derived from it synthesize type IV collagen, a structural protein of basement membranes. In cultures of cells, net production of collagen is stimulated 2-fold more than total cell protein by epidermal growth factor. Mammary adenocarcinoma cells also respond to epidermal growth factor but to a much reduced extent. This difference in growth factor responsiveness appears to be due to the production of collagen synthesis stimulating factors by the mammary tumor cells. Such factors have been partially purified and shown to differentially stimulate the incorporation of proline into collagenase-sensitive protein by 2.5-10-fold in normal rat mammary epithelium, normal rat kidney, and mouse 3T3 cells. The tumor factors do not stimulate net collagen production in cultures of tumor cells from which the factors are derived, suggesting that tumor cells produce sufficient stimulatory factors for optimal synthesis of collagen. Pulse-chase studies indicate that the tumor factors stimulate collagen synthesis rather than block collagen turnover. The activities in the extract have been partially purified by gel filtration, ion exchange column chromatography, and isoelectric focusing. The major species has a molecular weight of about 68,000 and a pI of 5.9. A smaller peak of activity with a molecular weight of 6,000 is also present. Since collagen synthesis appears to be necessary for the growth of mammary adenocarcinomas in vivo, production of these collagen synthesis stimulating factors may be important for tumor growth.

Adenocarcinoma↗
PubMed1982

Isolation and characterization of a growth factor (embryonin) from bovine fetuin which resembles alpha 2-macroglobulin.

A serum-free hormone-supplemented medium which was previously formulated for the growth of mouse embryonal carcinoma (EC) cells and rat mammary epithelial (REM) cells required the presence of crude bovine fetuin as a medium supplement for maintaining cell growth. This requirement could not be replaced by purified fetuin preparations. The major growth-promoting activity (embryonin) in the crude fetuin preparation has been purified to near homogeneity by carboxymethylcellulose chromatography and high performance gel filtration chromatography. Purified embryonin, 2 to 4 micrograms/ml, is able to stimulate the growth of mouse EC cells in a serum-free hormone-supplemented medium to a level that is achieved with 0.5 to 1 mg/ml of the crude fetuin preparation. The biological activity resides in a high molecular weight glycoprotein (Mr = 270,000). Three polypeptide chains are observed following reduction, a major polypeptide (Mr = 185,000) and two minor chains (Mr = 116,000 to 120,000 and 68,000). Embryonin differs from pure fetuin in molecular weight, isoelectric point, amino acid composition, and immunological reactivity. However, embryonin is similar to human alpha 2-macroglobulin (alpha 2M) in these physicochemical and immunological properties. Resemblance to alpha 2M is also indicated by the observation that alpha 2M used over the same protein concentration range as embryonin produces a comparable stimulation of EC cell growth in the absence of serum. In addition, embryonin and alpha 2M produce a 2- to 10-fold differential stimulation of collagen production in cultures of normal rat kidney and RME cells, a response which may be linked to the growth-promoting activity of these two proteins.

Amino Acids↗