Inhibition by dexamethasone of transforming growth factor beta1-induced apoptosis in rat hepatoma cells: a possible association with Bcl-xL induction

The authors previously reported that transforming growth factor beta1 (TGF-beta1) induces apoptosis in McA-RH7777 (7777) and McA-RH8994 (8994) rat hepatoma cell lines. Although these cell lines exhibit different responses to glucocorticoid treatment in various cellular functions and gene expression, dexamethasone (DEX) inhibited spontaneous and TGF-beta1-induced apoptosis in both. Analysis of analogous hormones in TGF-beta1-induced apoptosis in 8994 cells suggested the inhibitory effect to be glucocorticoid-specific. By cell-cycle analysis and DNA fragmentation assay using sodium butyrate, a G1-arrest-inducing reagent, regulation of apoptosis by TGF-beta1 and DEX was shown independent of the cell cycle. For elucidation of the mechanisms of anti-apoptotic action of DEX, the effects of various chemical probes on this apoptosis model were examined, and various reagents known to exhibit anti-apoptotic activity in other experimental systems were found to be ineffective. The effect of TGF-beta1 and DEX on cellular amounts of several apoptosis-related proteins, members of the Bcl-2 family, Bcl-2, Bcl-xL, Bcl-xS, Bad, and Bax was also examined. DEX drastically increased Bcl-xL in both cell lines irrespective of the presence of TGF-beta1. Bcl-2 and Bcl-xS proteins were not detected, and Bax and Bad content did not change by treatment with TGF-beta1 or DEX. Progesterone (Prog), a partial antagonist for glucocorticoid receptor, inhibited the effects of DEX on apoptosis and Bcl-xL expression in 8994 cells. Thus, Bcl-xL induction by DEX would appear closely associated with its inhibitory effect on spontaneous and TGF-beta1-induced apoptosis in the hepatoma cell lines.     

Inhibition of Fas antigen-mediated apoptosis of rheumatoid synovial cells in vitro by transforming growth factor beta 1

OBJECTIVE: To investigate the mitogenic and anti-apoptotic effects of transforming growth factor beta 1 (TGF beta 1) on rheumatoid synovial cells in vitro. METHODS: Synovial cells were cultured with or without TGF beta 1. After incubation, the proliferative response of synovial cells and the expression of Fas antigen and bcl-2 on synovial cells were examined. Finally, Fas antigen-mediated apoptosis of synovial cells was investigated by the addition of anti-Fas antibody. RESULTS: TGF beta 1 enhanced the proliferation of synovial cells in a dose-dependent manner. In addition, Fas antigen expression on synovial cells was inhibited by the addition of TGF beta 1 with up-regulation of bcl-2 expression. The addition of anti-Fas antibody induced synovial cell apoptosis. However, stimulation of synovial cells with TGF beta 1 became markedly resistant to Fas antigen-mediated apoptosis. The results were not affected by the addition of a neutralizing antibody to platelet-derived growth factor type AA (PDGF-AA), which suggests that the effect of TGF beta 1 on synovial cells was promoted via PDGF-AA-independent mechanisms. CONCLUSION: Our results suggest that TGF beta 1 promotes synovial cell proliferation through its mitogenic effect on synovial cells and interference with the apoptotic process mediated by the Fas antigen, resulting in the perpetuation of the synovial hyperplasia in patients with rheumatoid arthritis.     

Expression of transforming growth factor beta and transforming growth factor beta receptors on AIDS-associated Kaposi's sarcoma

Several humoral growth factors may contribute to the development and growth of AIDS-associated Kaposi's sarcoma (KS). They are either provided by chronically activated cells of the immune system or in an autocrine/paracrine manner by the neoplastic cells themselves. Transforming growth factor beta(TGF-beta) may directly enhance the growth of KS cells and tumor matrix formation. To mediate a signal both TGF-beta receptors type I and type II (TbetaR-I and TbetaR-II) have to be expressed. We investigated the expression of TGF-beta, TGF-beta receptors types I and II, and endoglin, a nonsignaling-type TbetaR-III, by means of immunohistochemistry on skin biopsies from patients with AIDS-related KS. We found that the TGF-beta ligand was expressed by KS cells in 9 of 11 samples. TbetaR-II was strongly expressed in 10 of 12 samples, but none of the investigated tumor samples stained for TbetaR-I. Endoglin was weakly expressed on all KS lesions and stained the endothelium of tumor-associated vessels in 92% of the samples. These findings show that most KS lesions have the ability to produce TGF-beta and that KS cells maintain a high expression of TbetaR-II in the absence of TbetaR-I, which may allow KS to escape growth inhibitory effects of endocrine or paracrine TGF-beta.     

Purification of transforming growth factor beta 1 from human platelets

Transforming growth factor-beta (TGF beta) is a growth and differentiation factor which can be released from many cell types. In previous studies, platelets were identified as a rich source of TGF beta. Here we present a rapid and convenient method for TGF beta purification from human platelets which includes acid-ethanol extraction and gelfiltration, cation exchange and reversed phase chromatography. All purification steps are performed under acidic conditions to prevent adsorption of TGF beta to the vial walls. In addition, volatile solvents and buffers were used which allowed easy removal of solvent and salt by lyophilization. Using this method pure TGF beta can be easily obtained in high yield (370 micrograms) from 20 units of platelet concentrate.     

Decreased expression of transforming growth factor beta 1 in blood plasma of guinea pigs fed vitamin C deficient diet

Liposarcoma is a malignant neoplasm of soft tissue. Its occurrence in the head and neck region is extremely rare. The case of a 26-year-old woman with neck liposarcoma is presented. The clinical manifestation, histopathology, possibility and results of the tumor treatment are described according to the literature.     

Relationship of transforming growth factor beta 1 to angiogenesis in gastric carcinoma

OBJECTIVE: To evaluate the prevalence of risk factors of coronary heart disease in the personnel of the General Hospital in Mexico City. MATERIAL AND METHODS: We studied 2,228 workers, 1,531 female (68.7%) and 697 male (31.2%) whose ages ranged from 16 to 65 years old in the period of 1993 to 1995. They were divided in work areas: Intendancy 477 (21.4%), Administrative, 697 (31.2%), Physicians, 495 (22.2%) and Nurses, 559 (25.0%). We collected clinical histories, anthropometric measures, and laboratory determinations of glucose, total cholesterol, LDL, HDL and triglicerydes. RESULTS: We found that 367 (14.9%) had total cholesterol above 240 mg/dl, with high values in females of the administrative area (17.1%) and males in the nursing department (26%), which was the highest tendency. Trigliceryde levels above 200 mg/dl were found in 208 males (24.6%) and 263 females (16.2%), with high prevalence in the nursing and administrative departments, in males (39.1 and 34.1% respectively). Obesity was present in 236 females (14.5%) and 97 males (11.5%). High blood pressure in 549 individuals (22.2%), 297 females (18.3%) and 252 males (29.8%) without significance regarding to work area. Smoking habits were positive in 32% of the total with highest prevalence in males from 30 to 45 years and in females from 30 to 50 years. We found an incidence of 6.24% of diabetes in all the subjects studied, 2.27% ignored the diagnosis at the moment they were studied. CONCLUSIONS: In this study we confirmed the high prevalence of risk factors of coronary heart disease in personnel of the General Hospital in Mexico City. In most cases, these risk factors that can be modified and, therefore, prevented.     

Down-regulated expression of transforming growth factor beta 1 mRNA in endometrial carcinoma

Transforming growth factor beta1 (TGF-beta1) is a potent modulator of cell proliferation in vitro, and recent studies have demonstrated its overexpression in several different tumours; nevertheless, the molecular mechanisms of TGF-beta1 action on cell growth and differentiation have not been fully elucidated. To clarify the role of TGF-beta and its receptor in human endometrial proliferation and differentiation, TGF-beta1 expression at both the mRNA and protein levels has been evaluated by using Northern blotting and immunohistochemistry, in both normal (atrophic, proliferative and secretory) and neoplastic (adenocarcinoma) endometrial samples. This study demonstrates that TGF-beta1 mRNA expression is dramatically reduced in endometrial carcinomas with respect to non-neoplastic tissues, whereas the immunohistochemical expression of TGF-beta1 is enhanced in the epithelial component of endometrial carcinomas compared with non-neoplastic tissues. These data suggest that TGF-beta1 acts as a paracrine regulator of endometrial cell proliferation and that it may contribute to the carcinogenic mechanisms of endometrial carcinoma.     

Plasma levels of transforming growth factor beta 1 in chronic liver disease

We describe the case of a 30-year-old female patient with a 7-year history of multiple sclerosis, who presented with an 18-month history of secondary amenorrhoea and vague symptoms which included poor sleep and impaired concentration. Endocrine investigations revealed hypogonadotrophic hypogonadism and GH deficiency, a probable consequence of a hypothalamic plaque. This is the first report of hypogonadotrophic hypogonadism and GH deficiency occurring in conjunction with multiple sclerosis. As such, it should raise suspicion of endocrine dysfunction occurring in a condition with such a vast spectrum of disability as multiple sclerosis.     

Polylactide pin with transforming growth factor beta 1 in delayed osteotomy fixation

The effect of an absorbable pin containing transforming growth factor beta 1 on fracture healing was studied in a rat model of delayed osteotomy fixation. Transforming growth factor beta 1 was mixed into a blend of L-lactide oligomer and a copolymer of epsilon-caprolactone and DL-lactide that was placed in the grooves of a self reinforced fracture fixation pin made of poly-LD-lactic acid copolymer. A distal femoral osteotomy was made in 54 rats and left untreated. A week later surgery was performed to fix the osteotomy with a fracture fixation pin in 48 rats. In the remaining six rats no fixation was performed. The pin that was used in the study group contained either 5 micrograms (15 rats) or 50 micrograms (15 rats) of the growth factor, while in the control group of 18 rats, an identical pin without growth factor was used. The femurs were examined radiographically, histologically, histomorphometrically, and microradiographically. Tetracycline labeling studies were used after a followup of 1, 3, and 6 weeks. Faster callus formation in the transforming growth factor beta 1 treated animals but no acceleration in the healing of the osteotomy is reported. The addition of bone growth factors to bioabsorbable fracture fixation materials may enhance bone healing.     

Phase 1 trial of transforming growth factor beta 2 in chronic progressive MS

Transforming growth factor (TGF)-beta2 is a pleiotropic cytokine associated with remissions in multiple sclerosis (MS) and amelioration of allergic encephalomyelitis. We assessed the safety of TGF-beta2 in an open-label trial of 11 patients with secondary progressive (SP) MS. Five patients had a reversible decline in the glomerular filtration rate. There was no change in expanded disability status scale or MRI lesions during treatment. Systemic TGF-beta2 may be associated with reversible nephrotoxicity, and further investigation of its therapeutic potential in MS should be performed with caution.     

Plasma transforming growth factor beta1 as a predictor of radiation pneumonitis

PURPOSE: To investigate prospectively the utility of plasma transforming growth factor beta1 (TGFbeta1) as a marker for the development of symptomatic radiation pneumonitis. MATERIALS AND METHODS: Seventy-three patients with lung cancer treated with curative intent are reported herein. Plasma TGFbeta1 samples were obtained before, weekly during, and at each follow-up after radiation therapy (RT). TGFbeta1 was extracted using an acid/ethanol method. An enzyme-linked immunosorbent assay was used to quantify plasma TGFbeta1 concentrations. The TGFbeta1 level at the end of RT was considered "normal" if it was both < or = 7.5 ng/ml and less than the pretreatment value. All patients were followed for at least 6 months, unless symptomatic pneumonitis developed sooner. Pneumonitis was defined by National Cancer Institute (NCI) common toxicity criteria. RESULTS: Fifteen of the 73 patients (21%) developed symptomatic pneumonitis and the remaining 58 (79%) did not. A normal plasma TGFbeta1 by the end of RT, as defined above, was more common in patients who did not develop pneumonitis. A return of the plasma TGFbeta1 to normal accurately identified patients who would not develop pneumonitis with both a sensitivity and positive predictive value of 90%. CONCLUSION: Plasma TGFbeta1 levels appear to be a useful means to identify patients at low risk for the development of pneumonitis from thoracic RT. Thus, monitoring of plasma TGFbeta1 levels may identify candidates for dose escalation studies in the treatment of lung cancer.     

Role of transforming growth factor beta 1 (TGF beta 1) in mediating androgen-induced growth inhibition in human adrenal cortex in vitro

We have previously found that the androgen receptor gene is expressed both in normal and adenomatous human adrenal cortex and in the NCI-H295 human adrenocortical cancer cell line. Furthermore, we have observed that dihydrotestosterone (DHT) at physiological concentrations (10(-11) M) inhibits human adrenocortical cell growth in vitro and slightly decreases c-myc RNA levels in NCI-H295 cells. As c-myc is probably not the main mechanism mediating DHT-induced inhibition of cell growth, other genes controlling cell proliferation may be involved. Transforming Growth Factor beta (TGF beta) is a regulatory peptide that acts by both autocrine and paracrine mechanisms to control proliferation and differentiation, and there is previous evidence that TGF beta may exert an antimitotic effect on human fetal adrenal cells in vitro. This study examines a possible role for TGF beta 1 in mediating the DHT-induced reduction of human adrenocortical cell growth. TGF beta 1 and its receptor (TGF beta RII) are expressed in DHT-treated and nontreated NCI-H295 cells; on Northern blot analysis 24-h treatment with DHT (10(-11) M) produced a small increase in TGF beta RII RNA, and quantitative RT-PCR showed a 1.5-fold increase in TGF beta 1 RNA levels. These findings suggest that TGF beta 1 and its receptor may be involved in DHT-induced inhibition of human adrenocortical cell growth.     

Induction of apoptosis in human ovarian cancer cell line HO-8910 by transforming growth factor beta 1

OBJECTIVE: To investigate the mechanism of inhibitory effects of Transforming Growth Factor beta 1 (TGF-beta 1) on human ovarian cancer cell in vitro. METHODS: The possibility of induction of apoptosis in human ovarian cancer cell line HO-8910 cells after treatment with TGF-beta 1 was studied by using methods of DNA electrophoresis, P1-staining, TdT-mediated dUTP-x nick end labeling and flow cytometer assay (FCM); and the kinetic change of expression of c-myc was also studied by relative quantified RT-PCR. RESULTS: DNA-strand nicks were present in cells after treatment with TGF-beta 1 at the final concentration of 20 ng/ml for 36 hours. The percent of labeled cells reached 75.55% on the time of 48 hours, PI staining-FCM assay also showed subdiploid peak of apoptotic cells at the same time. The typical apoptotic DNA ladder was present in genomic DNA preparation after treatment with TGF-beta 1 for 60 hours, meanwhile, the expression of c-myc in cells started to decrease beginning at treatment for 9 hours. CONCLUSIONS: TGF-beta 1 can induce apoptosis in HO-8910; such an inductive effect may occur mainly in G0/G1 phase. The effects of TGF-beta 1 on the inhibited expression of c-myc and on the enhancement of cAMP concentration may also play important roles in the process of apoptotic induction.     

Increased excretion of urinary transforming growth factor beta 1 in patients with diabetic nephropathy

Two cases of double outlet right ventricle with restrictive ventricular septal defect are described. This is an uncommon presentation that causes left ventricular dysfunction because of left ventricular outflow tract obstruction. The presence of an intact atrial septum leads to severe pulmonary hypertension, which tends to aggravate the right ventricular output. In the presence of a normal left ventricle, the authors suggest the possibility of enlargement of the ventricular septal defect in order to perform a biventricular repair. The association of a supramitral valve ring in both cases, and the isolation of the left subclavian artery and an aortopulmonary fenestration in one of these cases, are also discussed. In addition we explore factors that cause restrictive ventricular septal defects as well as the mechanisms that may lead to spontaneous closure of ventricular septal defect in a double outlet right ventricle.     

Two different signal transduction pathways can be activated by transforming growth factor beta 1 in epithelial cells

Signal transduction initiated by transforming growth factor beta 1 (TGF beta 1) was studied in two sublines of the same colon carcinoma cell line, which respond in opposite ways to TGF beta 1, by proliferation or by growth inhibition. TGF beta 1 activates ras proteins within 5 min of addition when it acts to inhibit growth but not when it acts as a mitogen. In both cases TGF beta 1 also rapidly modulates the activities of three protein kinases, detected by their in gel kinase activity on the mitogen-activated protein kinase (MAP kinase) substrate, myelin basic protein (MBP). When TGF beta 1 acts as a mitogen for U9 cells, it increases the activity of MBP kinases of 57, 105, and 130 kDa within 10 min of the addition without detectably activating ras proteins. When TGF beta 1 inhibits the growth of HD3 cells, it activates ras proteins and the 57-kDa MBP kinase within 5 min but inhibits the activity of the 105- and 130-kDa MBP kinases. In HD3 cells ras activation occurred in two signal transduction pathways, one from TGF beta 1 leading to growth inhibition and one from epidermal growth factor (EGF) leading to proliferation. In addition to ras proteins, EGF activates a different set of MBP kinases in HD3 cells than does TGF beta 1, MBP kinases of 85, 57, and 44 kDa. The latter is likely to be the 44-kDa MAP kinase extracellular signal-regulated kinase (erk) 1, because EGF treatment of HD3 cells activates erk1 by increasing its phosphotyrosine level. Therefore, in two closely related epithelial cell lines TGF beta 1 activates two different signal transduction pathways, one ras-dependent and one ras-independent, and modulates the activities of a set of MBP kinases.     

Function of the type V transforming growth factor beta receptor in transforming growth factor beta-induced growth inhibition of mink lung epithelial cells

The type V transforming growth factor beta (TGF-beta) is a 400-kDa nonproteoglycan membrane protein that co-expresses with the type I, type II, and type III TGF-beta receptors in most cell types. The type V TGF-beta receptor exhibits a Ser/Thr-specific protein kinase activity with distinct substrate specificity (Liu, Q., Huang, S. S., and Huang, J. (1994) J. Biol. Chem. 269, 9221-9226). In mink lung epithelial cells, the type V TGF-beta receptor was found to form heterocomplexes with the type I TGF-beta receptor by immunoprecipitation with antiserum to the type V TGF-beta receptor after 125I-TGF-beta affinity labeling or Trans35S-label metabolic labeling of the cells. The kinase activity of the type V TGF-beta receptor was stimulated after treatment of mink lung epithelial cells with TGF-beta. TGF-beta stimulation resulted in the growth inhibition of wild-type mink lung epithelial cells and to a lesser extent of the type I and type II TGF-beta receptor-defective mutants, although higher concentrations of TGF-beta were required for the growth inhibition of these mutants. TGF-beta was unable to induce growth inhibition in human colorectal carcinoma cells lacking the type V TGF-beta receptor but expressing the type I and type II TGF-beta receptors. These results suggest that the type V TGF-beta receptor can mediate the TGF-beta-induced growth inhibitory response in the absence of the type I or type II TGF-beta receptor. These results also support the hypothesis that loss of the type V TGF-beta receptor may contribute to the malignancy of certain carcinoma cells.