Elevated Transforming Growth Factor Beta Research Articles

Chronic exposure of mice to phthalates enhances TGF beta signaling and promotes uterine fibrosis

Phthalates are synthetic chemicals widely used as plasticizers and stabilizers in various consumer products. Because of the extensive production and use of phthalates, humans are exposed to these chemicals daily. While most studies focus on a single phthalate, humans are exposed to a mixture of phthalates on a regular basis. The impact of continuous exposure to phthalate mixture on uterus is largely unknown. Thus, we conducted studies in which adult female mice were exposed for 6 months to 0.15 ppm and 1.5 ppm of a mixture of phthalates via chow ad libitum. Our studies revealed that consumption of phthalate mixture at 0.15 ppm and 1.5 ppm for 6 months led to a significant increase in the thickness of the myometrial layer compared to control. Further investigation employing RNA-sequencing revealed an elevated transforming growth factor beta (TGF-β) signaling in the uteri of mice fed with phthalate mixture. TGF-β signaling is associated with the development of fibrosis, a consequence of excessive accumulation of extracellular matrix components, such as collagen fibers in a tissue. Consistent with this observation, we found a higher incidence of collagen deposition in uteri of mice exposed to phthalate mixture compared to unexposed controls. Second Harmonic Generation (SHG) imaging showed disorganized collagen fibers and nanoindentation indicated a local increase in uterine stiffness upon exposure to phthalate mixture. Collectively, our results demonstrate that chronic exposure to phthalate mixture can have adverse effects on uterine homeostasis.

Extracellular Matrix Stiffness and TGFβ2 Regulate YAP/TAZ Activity in Human Trabecular Meshwork Cells.

Primary open-angle glaucoma progression is associated with increased human trabecular meshwork (HTM) stiffness and elevated transforming growth factor beta 2 (TGFβ2) levels in the aqueous humor. Increased transcriptional activity of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), central players in mechanotransduction, are implicated in glaucomatous HTM cell dysfunction. Yet, the detailed mechanisms underlying YAP/TAZ modulation in HTM cells in response to alterations in extracellular matrix (ECM) stiffness and TGFβ2 levels are not well understood. Using biomimetic ECM hydrogels with tunable stiffness, here we show that increased ECM stiffness elevates YAP/TAZ nuclear localization potentially through modulating focal adhesions and cytoskeletal rearrangement. Furthermore, TGFβ2 increased nuclear YAP/TAZ in both normal and glaucomatous HTM cells, which was prevented by inhibiting extracellular-signal-regulated kinase and Rho-associated kinase signaling pathways. Filamentous (F)-actin depolymerization reversed TGFβ2-induced YAP/TAZ nuclear localization. YAP/TAZ depletion using siRNA or verteporfin decreased focal adhesions, ECM remodeling and cell contractile properties. Similarly, YAP/TAZ inactivation with verteporfin partially blocked TGFβ2-induced hydrogel contraction and stiffening. Collectively, our data provide evidence for a pathologic role of aberrant YAP/TAZ signaling in glaucomatous HTM cell dysfunction, and may help inform strategies for the development of novel multifactorial approaches to prevent progressive ocular hypertension in glaucoma.

Mechanosensitive channel inhibition attenuates TGFβ2-induced actin cytoskeletal remodeling and reactivity in mouse optic nerve head astrocytes

Astrocytes within the optic nerve head undergo actin cytoskeletal rearrangement early in glaucoma, which coincides with astrocyte reactivity and extracellular matrix (ECM) deposition. Elevated transforming growth factor beta 2 (TGFβ2) levels within astrocytes have been described in glaucoma, and TGFβ signaling induces actin cytoskeletal remodeling and ECM deposition in many tissues. A key mechanism by which astrocytes sense and respond to external stimuli is via mechanosensitive ion channels. Here, we tested the hypothesis that inhibition of mechanosensitive channels will attenuate TGFβ2-mediated optic nerve head astrocyte actin cytoskeletal remodeling, reactivity, and ECM deposition. Primary optic nerve head astrocytes were isolated from C57BL/6J mice and cell purity was confirmed by immunostaining. Astrocytes were treated with vehicle control, TGFβ2 (5 ng/ml), GsMTx4 (a mechanosensitive channel inhibitor; 500 nM), or TGFβ2 (5 ng/ml) + GsMTx4 (500 nM) for 48 h. FITC-phalloidin staining was used to assess the formation of f-actin stress fibers and to quantify the presence of crosslinked actin networks (CLANs). Cell reactivity was determined by immunostaining and immunoblotting for GFAP. Levels of fibronectin and collagen IV deposition were also quantified. Primary optic nerve head astrocytes were positive for the astrocyte marker GFAP and negative for markers for microglia (F4/80) and oligodendrocytes (OSP1). Significantly increased %CLAN-positive cells were observed after 48-h treatment with TGFβ2 vs. control in a dose-dependent manner. Co-treatment with GsMTx4 significantly decreased %CLAN-positive cells vs. TGFβ2 treatment and the presence of f-actin stress fibers. TGFβ2 treatment significantly increased GFAP, fibronectin, and collagen IV levels, and GsMTx4 co-treatment ameliorated GFAP immunoreactivity. Our data suggest inhibition of mechanosensitive channel activity as a potential therapeutic strategy to modulate actin cytoskeletal remodeling within the optic nerve head in glaucoma.

Heterogeneous addiction to transforming growth factor-beta signalling in recessive dystrophic epidermolysis bullosa-associated cutaneous squamous cell carcinoma.

Recessive dystrophic epidermolysis bullosa (RDEB) is associated with a high mortality rate due to the development of life-threatening, metastatic cutaneous squamous cell carcinoma (cSCC). Elevated transforming growth factor-beta (TGF-β) signalling is implicated in cSCC development and progression in patients with RDEB. To determine the effect of exogenous and endogenous TGF-β signalling in RDEB cSCC with a view to assessing the potential of targeting TGF-β signalling for RDEB cSCC therapy. A panel of 11 patient-derived RDEB cSCC primary tumour keratinocyte cell lines (SCCRDEBs) were tested for their signalling and proliferation responses to exogenous TGF-β. Their responses to TGF-β receptor type-1 (TGFBR1) kinase inhibitors [SB-431542 and AZ12601011 (AZA01)] were tested using in vitro proliferation, clonogenicity, migration and three-dimensional invasion assays, and in vivo tumour xenograft assays. All SCCRDEBs responded to exogenous TGF-β by activation of canonical SMAD signalling and proliferative arrest. Blocking endogenous signalling by treatment with SB-431542 and AZ12601011 significantly inhibited proliferation (seven of 11), clonogenicity (six of 11), migration (eight of 11) and invasion (six of 11) of SCCRDEBs. However, these TGFBR1 kinase inhibitors also promoted proliferation and clonogenicity in two of 11 SCCRDEB cell lines. Pretreatment of in vitro TGFBR1-addicted SCCRDEB70 cells with SB-431542 enhanced overall survival and reduced tumour volume in subcutaneous xenografts but had no effect on nonaddicted SCCRDEB2 cells in these assays. Targeting TGFBR1 kinase activity may have therapeutic benefit in the majority of RDEB cSCCs. However, the potential tumour suppressive role of TGF-β signalling in a subset of RDEB cSCCs necessitates biomarker identification to enable patient stratification before clinical intervention.

Diosmin ameliorates inflammation, insulin resistance, and fibrosis in an experimental model of non-alcoholic steatohepatitis in rats

Non-alcoholic steatohepatitis (NASH) is becoming of increasing significance due to its growing global prevalence and risk of progression to end-stage liver disease. This study was carried out to investigate the potential anti-inflammatory, insulin sensitizing, and antifibrotic effects of diosmin in an experimental model of NASH induced in rats using high-fat diet (HFD) and 30 mg/kg streptozotocin (STZ). Diosmin was administered orally at dose of 100 mg/kg for 8 weeks. Stained tissue sections were examined for histopathological signs of NASH, collagen deposition, and alpha smooth muscle actin (α-SMA) expression. In addition, insulin resistance, dyslipidemia, inflammation, and fibrosis markers were assessed. HFD/STZ successfully induced different NASH features such as insulin resistance seen by elevated fasting blood glucose levels and homeostasis model assessment for insulin resistance. Moreover, induced rats demonstrated dyslipidemia, a significant elevation in tumor necrosis factor alpha (TNF-α) and interleukin-6 levels, and an imbalance in the oxidative status of the liver. Those events altogether precipitated initiation of liver fibrosis as confirmed by elevated transforming growth factor beta (TGF-β) levels. Treatment with diosmin demonstrated multiple beneficial effects as it significantly ameliorated histopathological NASH findings, lowered TNF-α, interleukin-6, and malondialdehyde levels, improved lipid and glucose metabolism, and lowered hepatic TGF-β, α-SMA, and collagen content compared to untreated rats. The present study represents a drug repositioning scenario as diosmin is widely used for management of blood vessel disorders and is known to be well tolerated. This encourages the extension of our study to the clinical setting to explore diosmin effects in NASH patients.

Dysregulated YAP1/TAZ and TGF-β signaling mediate hepatocarcinogenesis in Mob1a/1b-deficient mice

Mps One Binder Kinase Activator (MOB)1A/1B are core components of the Hippo pathway that coactivate large tumor suppressor homolog (LATS) kinases. Mob1a/1b double deficiency in mouse liver (LMob1DKO) results in hyperplasia of oval cells and immature cholangiocytes accompanied by inflammatory cell infiltration and fibrosis. More than half of mutant mice die within 3 wk of birth. All survivors eventually develop liver cancers, particularly combined hepatocellular and cholangiocarcinomas (cHC-CCs) and intrahepatic cholangiocellular carcinomas (ICCs), and die by age 60 wk. Because this phenotype is the most severe among mutant mice lacking a Hippo signaling component, MOB1A/1B constitute the critical hub of Hippo signaling in mammalian liver. LMob1DKO liver cells show hyperproliferation, increased cell saturation density, hepatocyte dedifferentiation, enhanced epithelial-mesenchymal transition and cell migration, and elevated transforming growth factor beta(TGF-β)2/3 production. These changes are strongly dependent on Yes-Associated Protein-1 (Yap1) and partially dependent on PDZ-binding motif (Taz) and Tgfbr2, but independent of connective tissue growth factor (Ctgf). In human liver cancers, YAP1 activation is frequent in cHC-CCs and ICCs and correlates with SMAD family member 2 activation. Drug screening revealed that antiparasitic macrocyclic lactones inhibit YAP1 activation in vitro and in vivo. Targeting YAP1/TAZ with these drugs in combination with inhibition of the TGF-β pathway may be effective treatment for cHC-CCs and ICCs.

Activation of Cardiac Fibroblasts by Ethanol Is Blocked by TGF‐β Inhibition

Alcohol abuse is the second leading cause of dilated cardiomyopathy, a disorder specifically referred to as alcoholic cardiomyopathy (ACM). Rodent and human studies have revealed cardiac fibrosis to be a consequence of ACM, and prior studies by this laboratory have associated this occurrence with elevated transforming growth factor-beta (TGF-β) and activated fibroblasts (myofibroblasts). To date, there have been no other studies to investigate the direct effect of alcohol on the cardiac fibroblast. Primary rat cardiac fibroblasts were cultured in the presence of ethanol (EtOH) and assayed for fibroblast activation by collagen gel contraction, alpha-smooth muscle actin (α-SMA) expression, migration, proliferation, apoptosis, collagen I and III, and TGF-β expression. The TGF-β receptor type 1 inhibitor compound SB 431542 and a soluble recombinant TGF-βII receptor (RbII) were used to assess the role of TGF-β in the response of cardiac fibroblasts to EtOH. Treatment for cardiac fibroblasts with EtOH at concentrations of 100 mg/dl or higher resulted in fibroblast activation and fibrogenic activity after 24 hours including an increase in contraction, α-SMA expression, migration, and expression of collagen I and TGF-β. No changes in fibroblast proliferation or apoptosis were observed. Inhibition of TGF-β by SB 431542 and RbII attenuated the EtOH-induced fibroblast activation. EtOH treatment directly promotes cardiac fibroblast activation by stimulating TGF-β release from fibroblasts. Inhibiting the action of TGF-β decreases the fibrogenic effect induced by EtOH treatment. The results of this study support TGF-β to be an important component in cardiac fibrosis induced by exposure to EtOH.

Elevated transforming growth factor-beta 1 (TGF-β1) levels in human fracture healing

IntroductionTransforming growth factor-beta 1(TGF-β1) is a regulatory protein, involved in bone fracture healing. Circulating TGF-β1 levels have been reported to be a predictor of delayed bone healing and non-union, suggesting active relationship between tissue and circulating TGF-β1 in fracture healing. The purpose of this study was to analyse TGF-β1 local and serum concentrations in fracture healing to further contribute to the understanding of molecular regulation of fracture healing. Patients and methodsSerum samples of 113 patients with long bone fractures were collected over a period of 6 months following a standardised time schedule. TGF-β1 serum concentrations were measured using ELISA. Patients were assigned to 2 groups: Group 1 contained 103 patients with physiological healing. Group 2 contained 10 patients with impaired healing. Patients in both groups were matched. One patient of the group 2 had to be excluded because of missing match partner. In addition, fracture haematoma from 11 patients of group 1 was obtained to analyse local TGF-β1 concentrations. 33 volunteers donated serum which served as control. ResultsTGF-β1 serum concentrations increased during the early healing period and were significantly higher in patients with physiological healing compared to controls (P=0.04). Thereafter, it decreased continuously between weeks 2 and 8 and fell again after week 8. TGF-β1 serum concentrations in patients with physiological healing were significantly higher at week 24 compared to controls (P=0.05). In non-unions, serum concentrations differed significantly from those of controls at week 6 (P=0.01). No significant difference in between patients with physiological and impaired fracture healing was observed. Fracture haematoma contained significantly higher TGF-β1 concentrations than peripheral serum of the patients (P=0.017). ConclusionElevated levels of TGF-β1 in haematoma and in serum after bone fracture especially during the entire healing process indicate its importance for fracture healing.

Molecular aging and rejuvenation of human muscle stem cells

Very little remains known about the regulation of human organ stem cells (in general, and during the aging process), and most previous data were collected in short-lived rodents. We examined whether stem cell aging in rodents could be extrapolated to genetically and environmentally variable humans. Our findings establish key evolutionarily conserved mechanisms of human stem cell aging. We find that satellite cells are maintained in aged human skeletal muscle, but fail to activate in response to muscle attrition, due to diminished activation of Notch compounded by elevated transforming growth factor beta (TGF-β)/phospho Smad3 (pSmad3). Furthermore, this work reveals that mitogen-activated protein kinase (MAPK)/phosphate extracellular signal-regulated kinase (pERK) signalling declines in human muscle with age, and is important for activating Notch in human muscle stem cells. This molecular understanding, combined with data that human satellite cells remain intrinsically young, introduced novel therapeutic targets. Indeed, activation of MAPK/Notch restored ‘youthful’ myogenic responses to satellite cells from 70-year-old humans, rendering them similar to cells from 20-year-old humans. These findings strongly suggest that aging of human muscle maintenance and repair can be reversed by ‘youthful’ calibration of specific molecular pathways.

Biomarkers of Endothelial Injury in Focal Segmental Glomerulosclerotic Nephrosis

Enhanced circulating endothelial cells, elevated transforming growth factor beta, and depleted vascular endothelial growth factor were observed in nephrosis associated with focal segmental glomerulosclerosis (FSGS). Increased endothelial cell loss may be due to the elevated transforming growth factor beta, which can induce apoptosis of podocyte as well as tubular epithelium. Such injury may explain the depletion of vascular endothelial growth factor and increased endothelial cell loss in these patients. There biomarkers may have relevance to the altered intrarenal hemodynamics commonly observed in FSGS nephrosis.

Biomarkers of Endothelial Injury in Focal Segmental Glomerulosclerotic Nephrosis

Enhanced circulating endothelial cells, elevated transforming growth factor beta, and depleted vascular endothelial growth factor were observed in nephrosis associated with focal segmental glomerulosclerosis (FSGS). Increased endothelial cell loss may be due to the elevated transforming growth factor beta, which can induce apoptosis of podocyte as well as tubular epithelium. Such injury may explain the depletion of vascular endothelial growth factor and increased endothelial cell loss in these patients. There biomarkers may have relevance to the altered intrarenal hemodynamics commonly observed in FSGS nephrosis.

Peripheral T-cell Lymphoma Presenting with Rapidly Progressing Myelofibrosis

Myelofibrosis following peripheral T-cell lymphoma has rarely been reported. Described here is a case of peripheral T-cell lymphoma with myelofibrosis and elevated transforming growth factor beta (TGF- β ). A 69 years old male was admitted due to anemia and thrombocytopenia. His bone marrow showed fibrosis and was infiltrated with small lymphoid cells and a few residual normal hematopoietic cells. He had presented with hepatosplenomegaly and left inguinal lymph node swelling. Biopsy of the left inguinal lymph node revealed diffuse mature small lymphoid cells with atypical nuclei. Immunophenotyping of the small lymphoid cells were positive for CD3, CD8, TCR α β and HLA-DR and were negative for CD4, CD19, CD20 and CD56. T-cell receptor β -chain gene was rearranged in bone marrow cells. He was diagnosed as having peripheral T-cell lymphoma complicated with myelofibrosis. Chemotherapy was administrated which improved his pancytopenia and symptoms. Two years later, anemia and thrombocytopenia developed rather quickly, he died because of progression of myelofibrosis with severe pancytopenia.

Elevated transforming growth factor beta levels in the plasma of cytokine-treated cancer patients and normal allogeneic stem cell donors

Allogeneic blood stem-cell donors demonstrate more vigorous mobilization of CD34(+) cells to the circulation in response to cytokine administration than do autologous donors. Transforming growth factor (TGF-beta1) has been implicated as a mobilization inhibitor. A study was designed to determine whether plasma TGF-beta1 levels are elevated in cytokine-mobilized autologous cancer donors compared with cytokine-mobilized normal donors. Plasma collected from 29 autologous cancer donors and 33 normal allogeneic stem-cell donors following administration of mobilizing cytokines just prior to the first collection was assayed for TGF-beta1 using a sandwich-type ELISA. Plasma from three volunteers not treated with cytokine was also analyzed. Comparisons were made using the Student's t test on log-transformed data. Average TGF-beta1 levels in the plasma of cancer patients were significantly higher than in allogeneic stem-cell donors (4.4 ng/mL versus 7.2 ng/mL; p = 0.038). The allogeneic donors required fewer collections to harvest greater numbers of CD34(+) cells and colony-forming unit granulocyte-macrophage (CFU-GM) than autologous donors. Plasma from three untreated volunteers had mean TGF-beta1 levels of 0.36 ng/mL, with all three levels below the 25th percentile for allogeneic donors and the 5th percentile for cancer patients. Cytokine administration was associated with increased plasma TGF-beta1 levels. The levels were higher in cancer patients being mobilized for stem-cell collection than in allogeneic blood stem-cell donors. These differences could underlie the increased number of apheresis procedures required to harvest autologous graft products from cancer patients.

Study on the secretion of cytokines from osteoblasts stimulated with prostaglandin E1.

In previous studies, prostaglandin (PG) E1 was found not only to enhance the effect of rhBMP, but also to increase orthotopic osteoconduction and enhance bone formation, even when used alone, as well as increasing the physical strength of implanted porous hydroxyapatite ceramics (HAP). In the present study, the secretion of cytokines from MC3T3-E1 cells was investigated, which is a cell line of osteoblasts derived from the mouse skull, stimulated in vitro by 10(-5) M and 10(-6) M PGE1, in order to elucidate the mechanism of action of PGE1. The cytokines examined included transforming growth factor (TGF) beta 1, interleukin (IL)-6, and IL-1 beta. The results of this study clarify the mechanism of enhancement of osteogenesis by PGE1. Elevated TGF beta 1 plays a very important role, and the findings are significant because they may provide the basis for the establishment of a rational clinical combined application of these materials.

Immunomodulation in an Infant with Familial Hemophagocytic Lymphohistiocytosis Following Chemotherapy

ABSTRACT Familial hemophagocytic lymphohistiocytosis (FHLH) is an autosomal recessive disorder associated with hepatosplenomegaly, cytopenias, lymphohistiocytic accumulation in the reticuloendothelial system and hemophagocytosis. Immunological dysregulation can occur with defective T-and NK-cell function; macrophage activation and cytokine production. Elevated transforming growth factor beta (TGF/β) produced by activated T cells and monocytes can be anti-inflammatory, whereas interleukin-6 (IL-6) induces T-cell proliferation and activation. We report the clinical and immunological evaluation of a 5-month-old Hispanic infant with FHLH. The evaluation included TGF/β, IL-6, nitric oxide (NO), and extended lymphocyte phenotypes, CD3+, CD4+, CD8+, CD28+, CD95+, CD45RA+, CD62L+, HLA-DR+, CD38+, CD69+ using enzyme-linked immunoadsorbent assay (ELISA), Greiss reagent, and 4′ color flow cytometry pre- and postchemotherapy with VP16 @ 65 mg/M2 and dexamethasone over 10 courses of treatment. TGFβ (924.4–4286.8 pg/mL...

The Expression of IL-1, IL-6, and TGF-β in the Synovial Fluid of Horses with Surgically-Induced Transient Synovitis

SummaryThis study investigates the presence of various cytokines in the synovial fluid of three horses with surgicallyinduced synovitis in one antebrachiocarpal joint. Synovial fluids were sampled from experimental and control joints, preoperatively and at two and 30 days post-operatively. Samples were analyzed for interleukin-1 and interleukin- 6 bioactivities with a bioassay, and for transforming growth factor-beta protein by ELISA. Peak cytokine levels were detected on day two post-synovectomy, and returned to pre-operative levels by 30 days post-synovectomy (Interleukin-6 in treated joints: day #0; 0.53 ±0.2, day #2; 9.8 ± 0.7, day #30; 0.4 ± 0.2. Transforming growth factorbeta in treated joints: day #0; 314 ± 69, day #2; 1101 ± 325, day #30; 321 ± 101). Arthrocentesis alone (i.e. control joints) caused no increase in interleukin- 1, interleukin-6 and transforming growth factor-beta levels. Interleukin-1 and interleukin-6 are thought to both prevent anabolic and enhance catabolic effects within articular cartilage matrices, whereas it has been proposed that transforming growth factor-beta may have a protective effect on the articular cartilage. This study is the first to document elevated transforming growth factor-beta levels in equine joints.This study documents elevated levels of transforming growth factor-beta, interleukin-1 and interleukin-6 in the joints of horses with surgically-induced transient synovitis.

Acute ethanol consumption synergizes with trauma to increase monocyte tumor necrosis factor ? production late postinjury

The hypothesis that acute ethanol uptake plus trauma can synergize to increase immunosuppression was tested. We found that, unlike non-alcohol-exposed patients, patients with acute alcohol use prior to trauma have a transient decrease in monocyte tumor necrosis factor alpha (TNF alpha) production during the very early postinjury (0-3 days) period. However, TNF alpha production by these alcohol-exposed patients' monocytes (M0) became hyperelevated late postinjury (> 9 days). Consequently, these massively elevated M0 TNF alpha levels can contribute to posttrauma immunosuppression after acute alcohol use. We also demonstrate that normal monocyte activation with the superantigen, Staphylococcus enterotoxin B (SEB), results in a preferential induction of cell-associated M0 TNF alpha production, described as characteristic of immunosuppressed trauma patients. Acute in vitro ethanol treatment down-regulated the elevated TNF alpha production by trauma patients' M0 after either SEB, muramyl-dipeptide (MDP), interferon-gamma plus MDP, or lipopolysaccharide (LPS) stimulation. Both SEB- and LPS-induced TNF alpha mRNA induction was inhibited by acute alcohol treatment in normal M0, indicating that ethanol can regulate cytokine gene expression. An additional immunosuppressive effect of acute ethanol's stimulation was suggested by its induction of elevated transforming growth factor beta production in trauma patients' activated M0.

Transgenic models for the study of prostate cancer

Transgenic model systems provide tools for obtaining information that clarifies important relationships between genetic alterations and carcinogenesis. One such relationship is the induction of specific growth factor activities by dominantly acting oncogenes. Using a "transgenic organ" model referred to as mouse prostate reconstitution (MPR) under conditions where the ras and myc oncogenes were introduced using a recombinant retrovirus into both the mesenchymal and epithelial compartments of the urogenital sinus, poorly differentiated prostate cancer (PC) was produced with high frequency (> 90%) in inbred C57BL/6 mice. Time-course studies using northern blotting and immunohistochemical analysis showed that the transition from benign to malignant status invariably was associated with the induction of elevated transforming growth factor-beta 1 (TGF-beta 1) expression. Additional immunohistochemical analysis of TGF-beta 1 in human PC and benign prostatic hyperplasia (BPH) showed that positive extracellular staining was significantly more extensive in PC compared with BPH. This differential staining pattern was evident in focal areas of PC adjacent to BPH. These findings in both the MPR model system and human PC suggest that elevated TGF-beta 1 expression is involved in the progression to malignancy and that its pattern of expression may become a useful marker of PC. Additional studies using transgenic animal models will continue to provide important clinically useful information about PC in man.

Genetic predisposition and mesenchymal-epithelial interactions in ras+myc-induced carcinogenesis in reconstituted mouse prostate.

Using a mouse prostate reconstitution (MPR) model system, strain-specific responses to the ras and myc oncogenes were investigated. When ras + myc were introduced into both the mesenchymal and epithelial compartments of the urogenital sinus, poorly differentiated prostate cancer was produced at a high frequency (> 90%) in inbred C57BL/6 mice. In contrast, under similar conditions, inbred BALB/c MPRs formed benign prostatic hyperplasia that converted to cancer at a low frequency (< 10%). Restricting the oncogenes to the mesenchymal or epithelial compartments revealed that oncogene activities were more pronounced in the mesenchyme of C57BL/6 mice and resulted in elevated transforming growth factor-beta 1 expression along with a severe desmoplastic reaction. Heterologous MPRs composed of BALB/c mesenchyme and C57BL/6 epithelium or vice versa demonstrated that intrinsic properties of BALB/c mesenchyme can arrest the progression of ras + myc-initiated C57BL/6 epithelium from benign hyperplasia to malignant carcinoma.

Transforming growth factor beta 1 as a biomarker for prostate cancer.

Using the mouse prostate reconstitution (MPR) model system, under conditions where the ras and myc oncogenes are introduced via a recombinant retrovirus into both the mesenchymal and epithelial compartments of the urogenital sinus, poorly differentiated prostate cancer is produced with high frequency (> 90%) using inbred C57BL/6 mice. Northern blotting and immunohistochemical analysis showed that the transition from benign prostatic hyperplasia (BPH) to prostate cancer is invariably associated with the induction of elevated transforming growth factor-beta 1 (TGF-beta 1) expression. Similar analysis of TGF-beta 1 in human BPH and prostate cancer is consistent with our MPR results and indicates that the accumulation of extracellular TGF-beta 1 is significantly more intense in prostate cancer compared to normal or benign prostate tissues. Interestingly, where benign pathologies are observed in the prostatic stroma in the presence of benign prostatic epithelium, extracellular TGF-beta 1 is seen predominantly in the stromal compartment. Experimental studies clearly demonstrate that mRNA levels of TGF-beta 1 and other growth related genes are regulated by androgens in prostate cancer cells. Overall, our results suggest that elevated TGF-beta 1 is involved in the development of prostate cancer. Direct determination of TGF-beta 1 levels and distribution as well as analysis of localized and systemic effects produced by TGF-beta 1 may serve as useful biomarkers for prostate cancer.