Angiogenic factor of a rat mammary tumor cell line (RMT-1) (I). Secretion of two distinct angiogenic factors into serum-free conditioned medium by RMT-1 cells.

Serum-free conditioned medium of a rat mammary tumor cell line RMT-1, established from a rat mammary carcinoma induced by 7,12-dimethylbenz[a]anthracene (DMBA), produced the complete angiogenic response in both rabbit cornea and chick embryo chorioallantoic membrane assays. The angiogenic activity in the RMT-1 conditioned medium was separated into two fractions on a column of heparin-Sepharose; one was eluted with 0.1 M NaCl and the other with 0.

Suppression of lipoprotein lipase in 3T3-L1 cells by a mediator produced by SEKI melanoma, a cachexia-inducing human melanoma cell line.

Production of a cachexia-inducing factor(s) by the SEKI melanoma cell line, established from a human melanoma, has been well documented. Conditioned medium from cultures of this melanoma cell line contains a factor(s) that inhibits the activity of lipoprotein lipase (LPL) in fully differentiated 3T3-L1 adipocytes. The mode of inhibition of this enzyme by the factor, i.

Inhibition of angiogenesis by vitamin D3 analogues.

The effects of vitamin D3 and two analogues on embryonic angiogenesis were studied in 4.5-day-old chick embryo chorioallantoic membranes. The active metabolite of vitamin D3, 1 alpha,25-dihydroxyvitamin D3, and a synthetic vitamin D3 analogue, 22-oxa-1 alpha,25-dihydroxyvitamin D3, inhibited angiogenesis in a dose-dependent manner, the inhibition occurring in the picomolar range.

A highly potent antiangiogenic activity of retinoids.

Four retinoids, i.e. retinol (vitamin A), retinoic acid, retinyl acetate and synthetic chalcone carboxylic acid (Ch 55), were examined for their effects on embryonic angiogenesis using 4.

Comparison of the regional distribution of calspectin (nonerythroid spectrin or fodrin), alpha-actinin, vinculin nonerythroid protein 4.1, and calpactin in normal and avian sarcoma virus- or Rous sarcoma virus-induced transformed cells.

With fluorescence and interference reflection microscopy (IRM), we compared the regional distribution of calspectin, its interacting proteins (nonerythroid protein 4.1 and calpactin), alpha-actinin, and vinculin in NRK cells and their avian sarcoma virus (ASV)- or temperature-sensitive (ts) Rous sarcoma virus (RSV)-transformed cells. The localization of these cytoskeletal proteins was determined with the specific antibodies.

Angiogenic activity of rat mammary carcinomas induced by 7,12-dimethylbenz[a]anthracene and its inhibition by medroxyprogesterone acetate: possible involvement of antiangiogenic action of medroxyprogesterone acetate in its tumor growth inhibition.

The significant inhibitory activity of medroxyprogesterone acetate (MPA) against mammary tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) was confirmed in female Sprague-Dawley (SD) rats, and was found to be independent of the estrogen receptor (ER) level. To facilitate elucidation of the mechanism underlying the antitumor activity of MPA against the rat mammary tumors (RMTs) regardless of ER status, the present study was conducted to determine whether or not a DMBA-induced RMT had the capacity to elicit angiogenic activity on tissue implantation into a rabbit cornea, and, if so, to determine whether or not the angiogenic activity of the RMT was inhibited by MPA. The RMTs obtained were classified into two groups based on the ER level; ER-positive and -negative groups.

Demonstration of 1 alpha,25-dihydroxyvitamin D3 receptor-like molecule in ST 13 and 3T3 L1 preadipocytes and its inhibitory effects on preadipocyte differentiation.

The active metabolite of vitamin D3, 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3), inhibited morphologic and enzymatic expression during differentiation of preadipocyte to adipocyte. In the presence of approximately 6.4-20 X 10(-10) M 1,25(OH)2D3, the triacylglycerol accumulation was only 50% of that of fully differentiated control cells.

Functional studies of newly synthesized benzoic acid derivatives: identification of highly potent retinoid-like activity.

Three newly synthesized benzoic acid derivatives (terephthalic acid anilides, chalcone carboxylic acid, and azobenzene carboxylic acid), with a certain structural similarity to retinoic acid, were examined for their retinoid-like bioactivity and their capacity to bind to cellular retinoid binding proteins. Two in vitro systems were used to evaluate their retinoid-like bioactivity: inhibition of adipose conversion of ST 13 murine preadipose cells and growth promotion of murine sarcoma virus (MSV)-transformed 3T3 cells in serum-free culture. All three compounds tested inhibited ST 13 adipose conversion at nanomolar concentrations in a manner similar to classical retinoids such as retinoic acid.

Preadipocyte differentiation in vitro: identification of a highly active adipogenic agent.

A highly active adipogenic agent was identified in an in vitro adipose conversion system. This agent, ADD 4743 (or ADD), was synthesized by Takeda Chemical Industries (Osaka) as a 3-hydroxy derivative of an oral antidiabetic agent, ciglitazone, and has been presumed to be an active metabolite of the latter substance. When ST 13 mouse preadipose cells were treated with micromolar concentrations of ADD they rapidly and uniformly converted into lipid-accumulating adipocytelike cells within 8-11 days after cell seeding.

SGP140: identification of a novel component on human polymorphonuclear leukocyte cell surface involved in chemotactic and phagocytic activities.

SGP140, which has been isolated as the major sialoglycoprotein of 140 kd molecular weight from a human T-leukemic cell line, was identified on the cell surface of polymorphonuclear leukocytes (PMNs). Specific antibody against SGP140 was prepared in rabbits and was used to probe the function of SGP140 on PMNs in this study. PMNs from healthy donors that were treated with the anti-SGP140 IgG showed remarkably diminished chemotactic as well as phagocytic activity.

Separation of sarcoma growth inhibitor from avian sarcoma virus-transformed rat cells.

A cell growth inhibitor was isolated from an avian sarcoma virus-transformed rat cell line (77N1), from which we had previously obtained a novel transforming growth factor, TGF gamma 2. The growth inhibitor (named SGI) was found in cell extract of 77N1 cells and was separable from TGF gamma 2 by means of ion exchange chromatography. SGI inhibited the DNA synthesis of serum-starved, TGF gamma 2-stimulated BALB3T3 cells as well as the spontaneous and TGF-induced colony formation of various cells in semisolid agar.

Isolation of two syngeneic cell lines from a rat mammary carcinoma: growth factor production by neoplastic epithelial cells.

Two distinctly different clonal cell lines were isolated from a mammary tumor induced by ingestion of 7,12-dimethylbenz[a]anthracene (CAS: 57-97-6) in a SD rat. Cells of one of the clones, RMT-1 clone E4, showed typical epithelial characters; it was concluded that they were derived from neoplastic mammary epithelial cells. The other clone, M2, exhibited characters consistent with its derivation from the normal mammary myoepithelial component.

Differentiation-associated increase of cAMP-dependent type II protein kinase in a murine preadipose cell line (ST 13).

The activity of cAMP-dependent protein kinase and cAMP binding activity were studied during the differentiation of ST 13 murine preadipocytes into adipocytes. We found that both activities were marginally detectable in preadipose cells and increased remarkably when the cells were induced to differentiate, preceding by several days the morphological adipose conversion. The increased cAMP-dependent protein kinase was identified as type II enzyme by means of DEAE-Sephacel chromatography and by photoaffinity labeling with 8-azido[3H]cAMP.

Effects of synthetic analogues of teleocidin, indolactam-V, on the differentiation of murine pre-adipose cells.

The ability of 4 steric isomers of indolactam-V, the synthetic analogues of the tumor promoter teleocidin, to affect the adipose conversion of ST-13 murine pre-adipose cells was investigated. The isomers share the common skeleton with teleocidin A and B, but unlike teleocidins, none of them possess the terepenoid chain in the molecule. We found that only one of the isomers, (-)-indolactam-V, was biologically active and produced up to 70% inhibition of adipose conversion, while the other 3 isomers were without effect.

Effects of retinoids on the proliferation of murine sarcoma virus-transformed cells in serum-free culture: potentiation of autocrine stimulation.

In a recent report, we described a growth stimulatory effect of vitamin A derivatives (retinoids) on murine sarcoma virus (MSV)-transformed cell lines when tested in a serum-free culture condition. These cell lines were presumed to proliferate via autostimulatory (autocrine) mechanism when serum was omitted from culture medium. In the present communication, we examined the effect of 6 synthetic derivatives on the serum-free proliferation of 2 MSV-transformed cell lines.

Stimulation of cell proliferation by vitamin A derivatives on murine sarcoma virus-transformed mouse cells in serum-free culture.

The effect of retinoids (Rds) on cell proliferation was studied in serum-free culture condition, using non-transformed and transformed derivatives of BALB 3T3. Cell proliferation of an SV40-transformed line was inhibited significantly by Rd treatment. However, proliferation of two cell lines that were transformed by a Kirsten and Moloney strain of murine sarcoma virus (MSV) and produced growth factor into culture medium, was remarkably stimulated by Rds.

Prevention of tumor promoter-mediated inhibition of preadipocyte differentiation by dexamethasone.

A clonal cell line of murine fibroblast (ST 13) undergoes a terminal differentiation into adipose cells in culture. A tumor promoter, 12-O-tetradecanoyl phorbol 13-acetate (TPA), reversibly inhibited the differentiation of ST 13 preadipocytes. The inhibition of differentiation was accompanied by changes in cell morphology and growth properties and by suppression of cellular insulin binding activity.

Protease resistance of transformed cells in culture: production of growth-promoting factor(s) by protease-resistant cells.

The protease-resistant character of malignantly transformed cells was studied. Surface labeling experiments revealed that the cell surface of transformed cells treated with, or grown in the presence of a neutral protease (Dispase) was drastically altered by proteolytic digestion, and showed that transformed cells could be stripped of many of their cell surface components without losing cell viability and growth ability. The protease-resistant character depended upon the degree of cell-crowding and was not expressed unless transformed cells were seeded at a high cell density, suggesting that some conditioning factor(s) contributes to its expression.

Establishment of a clonal cell line that differentiates into adipose cells in vitro.

From the fibroblastic cells of murine mammary tumor tissue we isolated a clonal cell line that could be induced to differentiate into fat-accumulating cells in vitro. Differentiation began after the cultures had reached confluence and was accompanied by (a) an increase in the incorporation of sodium acetate into the triglyceride (TG) fraction of cellular lipids, (b) a more than 50-fold increase in cellular TG content per milligram cell-layer protein basis and (c) the cessation of cellular DNA synthesis. The addition of insulin to the culture medium enhanced lipid accumulation and increased the fraction of cells that differentiated into adipocytes.

A new parameter for discriminating malignantly transformed cell lines from nontransformed counterparts: culture in liquid medium containing neutral protease.

Growth properties of malignantly transformed cell lines and their nontransformed counterparts were studied in the presence of a bacterial neutral protease (Dispase I). Among 10 transformed cell lines, 7 lines could proliferate in the presence of the protease in a floating state. Nontransformed cell lines and non-established cell strains failed to grow in this culture condition.