Induction Of Transforming Growth Factor-beta Research Articles

TGFBI is involved in the formation of polyploid cancer cells and the response to paclitaxel.

BackgroundMost human solid tumors are aneuploid; at the same time, polyploid cancer cells are found to be resistant to radiotherapy and chemotherapy and have a poor prognosis. The transforming growth factor beta induction (TGFBI) protein plays important roles in the development of tumors, depending on the cancer of origin.MethodsIn this study, we established polyploid clones of breast cancer treated with nocodazole. The drug sensitivity was measured by MTT assay. Western blot analysis was used to detect the expression of TGFBI protein in polyploid clones. The effects of paclitaxel on apoptosis, cell cycle and DNA ploidy were analyzed by flow cytometry. TGFBI protein expression was performed in samples from patients with epithelial ovarian tumors by immunohistochemical staining.ResultsWe found that compared with the MDA-MB-231 cell line, the expression of TGFBI in the HGF1806 cell line was relatively higher. In addition, compared with its parental cells, TGFBI showed relatively low expression in the polyploid breast cancer cell line T-MDA-MB-231. Compared with the empty vector, under paclitaxel treatment, the over-expression of TGFBI in MDA-MB-231 and T-MDA-MB-231 both showed a higher growth inhibition rate. After nocodazole treatment, the over-expression of TGFBI in MDF-MB-231 cells proved that the expression of tetraploid cells was lower compared to the control. The positive rate of TGFBI expression in ovarian cancer specimens before chemotherapy was 33.3% (5/15), which was higher than the positive rate of TGFBI expression in ovarian cancer specimens matched with relapsed specimens after treatment (0%, 0/15).ConclusionsTGFBI can increase the sensitivity of paclitaxel in polyploid cancer cells and participate in the formation of polyploidy in MDA-MB-231 induced by nocodazole. This newly recognized role of TGFBI provides further insight into the pathogenesis of polyploid cancer and identifies potential new therapeutic targets.

Long Term Stabilization of Expanding Aortic Aneurysms by a Short Course of Cyclosporine A through Transforming Growth Factor-Beta Induction

Abdominal aortic aneurysms (AAAs) expand as a consequence of extracellular matrix destruction, and vascular smooth muscle cell (VSMC) depletion. Transforming growth factor (TGF)-beta 1 overexpression stabilizes expanding AAAs in rat. Cyclosporine A (CsA) promotes tissue accumulation and induces TGF -beta1 and, could thereby exert beneficial effects on AAA remodelling and expansion. In this study, we assessed whether a short administration of CsA could durably stabilize AAAs through TGF-beta induction. We showed that CsA induced TGF-beta1 and decreased MMP-9 expression dose-dependently in fragments of human AAAs in vitro, and in animal models of AAA in vivo. CsA prevented AAA formation at 14 days in the rat elastase (diameter increase: CsA: 131.9±44.2%; vehicle: 225.9±57.0%, P = 0.003) and calcium chloride mouse models (diameters: CsA: 0.72±0.14 mm; vehicle: 1.10±0.11 mm, P = .008), preserved elastic fiber network and VSMC content, and decreased inflammation. A seven day administration of CsA stabilized formed AAAs in rats seven weeks after drug withdrawal (diameter increase: CsA: 14.2±15.1%; vehicle: 45.2±13.7%, P = .017), down-regulated wall inflammation, and increased αSMA-positive cell content. Co-administration of a blocking anti-TGF-beta antibody abrogated CsA impact on inflammation, αSMA-positive cell accumulation and diameter control in expanding AAAs. Our study demonstrates that pharmacological induction of TGF-beta1 by a short course of CsA administration represents a new approach to induce aneurysm stabilization by shifting the degradation/repair balance towards healing.

Effects of Magnetic Resonance Imaging Contrast Agents on Human Umbilical Vein Endothelial Cells and Evaluation of Magnetic Resonance Imaging Contrast Media-Triggered Transforming Growth Factor-Beta Induction in Dermal Fibroblasts (HSF) as a Model for Nephrogenic Systemic Fibrosis

The objective of this study was to evaluate effects of 6 commercially available magnetic resonance contrast media (CM) on human umbilical vein endothelial cells (HUVEC) and the induction of transforming growth factor-beta (TGF-β) in dermal fibroblasts (HSF) as a possible model for the pathogenesis of nephrogenic systemic fibrosis. HUVECs were incubated with 10× and 20× of the molar standard blood concentration achieved with CM applications for magnetic resonance imaging examinations (10× and 20× concentration) for 24 hours using gadolinium-based CM Gadovist, Magnevist, Multihance, and Omniscan, as well as Teslascan (Manganese-based), and Resovist (Iron-based). Proliferation kinetics (PK), colony formation, and viability assays were performed. Additionally, human dermal fibroblasts (HSF) were incubated for 24 hours with 1× and 20× concentration in all 6 CM, and TGF-β levels were assessed directly after the incubation period as well as on days 3 and 8 postincubation. HUVEC PK data show similar gains in cell numbers for all 6 CM in both concentration groups over the 17-day assessment period. Only cells incubated with Omniscan and Teslascan differed from the other groups on days 3 and 7 postincubation (P < 0.05). After day 7, a cell regain occurred in the Omniscan and Teslascan groups reaching the numbers of the other groups in sequel. Differences in colony formation were consistent with PK results with a statistically significant reduction in clonogenic activity for Teslascan and Omniscan in HUVEC cells, P < 0.05. No reduction in viability was seen for all groups and conditions. TGF-β expression of HSF cells incubated with 1× concentration and all CM did not differ significantly from control cells for any point in time investigated. At 20× concentration directly after incubation, TGF-β was significantly reduced for the Teslascan and Resovist group as 3 compared with control and all other CM groups, P < 0.05. On day 3 postincubation, only Resovist-incubated HSF cells showed a significant reduction of TGF-β (1.614, standard deviations: 89) as compared with the control group (2.883, standard deviations: 30) and the other CM. TGF-β was slightly reduced for all CM groups 8 days after incubation (not statistically significant, P > 0.05). After 24 hours of incubation with Omniscan and Teslascan (10× and 20× concentration), considerable short-term antiproliferative effects in HUVECs were observed. HSF cells (20× concentration) showed a reduction of TGF-β for Resovist and Teslascan directly after incubation, whereas TGF-β levels in HSF cells were slightly reduced for all CM 8 days after incubation. Therefore, TGF-β-mediated proliferative effects on fibroblasts or on collagen synthesis potentially leading to nephrogenic systemic fibrosis may mainly be triggered by tissue monocytes and macrophages in the peripheral blood instead of dermal fibroblasts.

Novel microdeletion in the transforming growth factor β type II receptor gene is associated with giant and large cell variants of nonsmall cell lung carcinoma

Mutations in the tumor suppressor gene transforming growth factor beta (TGFB) Type II receptor (TGFBR2) are frequently found in many cancers with microsatellite instability, but are less common in lung cancer. In the present study, we looked for mutations in TGFBR2 in nonsmall cell lung carcinoma (NSCLC) cells and tissues. A novel homozygous microdeletion (c.492_507del) was identified in two cell lines derived from the same giant cell carcinoma (GCC) and was confirmed in the corresponding tumor tissues. Furthermore, a heterozygous c.492_507del was found in the germ-line of one patient, as well as in the other GCC cases and some large cell carcinomas (LCC) but not in other subtypes of NSCLC. The 16 bp-microdeletion introduced a premature stop codon at positions 590-592 of the cDNA, resulting in a truncated TGFBR2 protein with a mutated transmembrane domain and loss of kinase domain. The GCC cells were characterized as being unresponsive to TGFB induction both in growth inhibition and stimulation of extracellular matrix protein. Moreover, after the reconstitution of wild-type TGFBR2 expression, the sensitivity to TGFB was restored. Therefore, mutated TGFBR2 seems to play an important role in the abrogation of TGFB signal transduction in GCC cells.

Sub-depressor dose of angiotensin type-1 receptor blocker inhibits transforming growth factor-beta-mediated perivascular fibrosis in hypertensive rat hearts.

Recently, we have shown that pressure overload transiently induces transforming growth factor-beta-mediated fibroblast proliferation and reactive myocardial fibrosis that extends from the perivascular space. However, the upper stream event of transforming growth factor-beta induction has remained unknown. Thus, we sought to determine whether angiotensin II mediates the fibrotic process in pressure-overloaded hearts. Male Wistar rats were administered orally everyday 0.1 mg/kg per day of candesartan, an angiotensin type-1 receptor blocker, or the vehicle from Day 7, and underwent a suprarenal aortic constriction (AC) at Day 0. This dose was the maximum dose of candesartan that does not induce the depressor effect in AC rats. In AC+ vehicle (control) rats, pressure overload induced myocardial transforming growth factor-beta expression and perivascular fibroblast proliferation at Day 3 and thereafter left ventricular hypertrophy associated with cardiomyocyte hypertrophy and perivascular fibrosis. AC+ candesartan rats showed suppressed transforming growth factor-beta expression and reduced number of proliferating fibroblasts, while not changing arterial pressure. Furthermore, perivascular fibrosis, but not myocyte hypertrophy, was significantly inhibited associated with reduced collagen mRNA expression. In conclusion, angiotensin II may play a role in reactive myocardial fibrosis in pressure-overloaded hearts, through the mechanism independent of hemodynamic change.

Role of p38 MAPK in Transforming Growth Factor β Stimulation of Collagen Production by Scleroderma and Healthy Dermal Fibroblasts

Transforming growth factor beta has been implicated as a mediator of excessive extracellular matrix deposition in scar tissue and fibrosis, including systemic sclerosis. To further characterize the mechanism of collagen gene expression in systemic sclerosis and healthy skin fibroblasts, we examined the role of p38 MAPK signaling in collagen gene regulation by transforming growth factor beta. Treatment of dermal fibroblasts with transforming growth factor beta resulted in a prolonged activation of p38 MAPK. Furthermore, a specific inhibitor of p38 suppressed transforming growth factor beta stimulation of collagen type I mRNA and the alpha2(I) collagen promoter activity. To further probe the role of p38 in collagen regulation by transforming growth factor beta, we utilized an expression vector containing p38alpha cDNA. Ectopic expression of p38alpha enhanced COL1A2 promoter activity and potentiated transforming growth factor beta stimulation of this promoter. The p38 response element in the COL1A2 promoter overlapped with the previously characterized transforming growth factor beta response element. Consistent with these observations, collagen type I mRNA and protein levels were increased in transforming-growth-factor-beta-stimulated fibroblasts transduced with an adenoviral vector expressing p38alpha. To determine the possible role of p38 in abnormal collagen production by systemic sclerosis fibroblasts, p38 protein levels were compared in systemic sclerosis and healthy skin fibroblasts. Both cell types exhibited similar total levels of p38 MAPK and similar kinetics of p38 activation in response to transforming growth factor beta. In conclusion, this study demonstrates a costimulatory role for p38 MAPK in transforming growth factor beta induction of the collagen type I gene. Expression levels and activation status of p38 are not consistently elevated in systemic sclerosis fibroblasts suggesting that the p38 MAPK pathway is not dysregulated in systemic sclerosis fibroblasts.

Cell cycle control and immunosuppression in organ transplantation

THE IMMUNE SYSTEM of the recipient is activated after organ transplantation. The principal immune cells involved in this activation are the T lymphocytes. Therefore, the current strategy for immunosuppression in organ transplantation is based on the inhibition of interleukin-2 (IL-2) and T-cell activation. Cyclosporine and tacrolimus, two main immunosuppressive drugs, in addition to their inhibition of IL-2 also induce the expression of transforming growth factor beta (TGF-b), one of the most potent immunosuppressive cytokines. The antiproliferative effects of TGF-b are believed to be via induction of the cell cyclin inhibitor p21. The activation of cyclin dependent kinases (CdKs) have been shown during T-cell activation, and we have previously demonstrated that cyclosporine induces p21 via the induction of TGF-b. We have also demonstrated that both in vitro and in vivo p21 transgenesis result in the inhibition of lymphocyte proliferation and increased susceptibility to cyclosporine. The main theme of this study is demonstrated in Fig 1. MATERIAL AND METHODS

Transforming growth factor-beta induction of type-1 plasminogen activator inhibitor. Pericellular deposition and sensitivity to exogenous urokinase.

The human tumor cell line HT-1080 was used as a model system to study the effects of transforming growth factor-beta (TGF beta) on polypeptide synthesis and proteolytic activity of malignant cells. Confluent cultures were exposed to TGF beta under serum-free conditions, and alterations in the production of proteins were examined by metabolic labeling and polypeptide analysis. TGF beta induced the synthesis and secretion of the Mr 47,000 endothelial type plasminogen activator inhibitor (PAI-1) as shown by reverse zymography, immunblotting, and immunoprecipitation analyses. TGF beta-induced PAI-1 was rapidly deposited in the growth substratum of the cells as shown by metabolic labeling and extraction of the cultures with sodium deoxycholate. Using pulse-chase experiments, we found a relatively fast turnover of substratum-associated PAI-1. Exogenously added urokinase released PAI-1 from the substratum even in the presence of the plasmin inhibitor aprotinin, suggesting a direct effect of urokinase. Immunoreactive complexes of higher molecular weight were subsequently detected in the medium. Epidermal growth factor, transforming growth factor-alpha, platelet-derived growth factor, and insulin did not elicit similar effects on the amount of PAI-1. TGF beta also inhibited the anchorage-independent growth of HT-1080 cells at the same concentrations at which it induced PAI-1. These results indicate that TGF beta can modulate the extracellular proteolytic activity of cultured cells by enhancing the secretion and deposition of PAI-1 into their microenvironment. It remains to be established whether TGF beta inhibition of anchorage-independent growth of these cells is associated with the induction of PAI-1.