transforming-growth-factor-beta and Angiofibroma

Patients with tuberous sclerosis complex (TSC) develop fibrous tumours in the brain, skin, kidney, heart and lungs due to TSC1/2 mutations. In the skin, patients develop angiofibromas that have vascular and fibrotic components in which transforming growth factor (TGF)-β and matrix metalloproteinase (MMP)-2 are important.. To investigate if the TGF-β axis and MMP-2 play an important role in the pathogenesis of TSC angiofibromas.. Samples from TSC angiofibromas and normal skin were measured for expression of TGF-β and MMP-2 by immunohistochemistry and real-time polymerase chain reaction. Fibroblasts grown from TSC angiofibromas (TSC fibroblasts) were incubated with TGF-β. Expression of ERK, AKT and S6K was measured by Western blotting, and MMP-2 expression and activity were determined by enzyme-linked immunosorbent assay and gelatin zymography, respectively.. There was an increase in the expression of TGF-β and MMP-2 in TSC tumours compared with those in normal skin. The baseline expression of MMP-2 was increased in conditioned medium from TSC fibroblasts. In addition, TGF-β enhanced MMP-2 production and activity, which could be abrogated by pretreatment with an AKT inhibitor (LY294002) but not with rapamycin. Finally, there was a significant colocalization of TGF-β and MMP-2 in the TSC tumours.. There is an increase of MMP-2 as a result of TGF-β acting through AKT in TSC tumour cells. This regulation of the TGF-β-AKT-MMP-2 axis is independent of mammalian target of rapamycin (mTOR) signalling. In addition to targeting the mTOR pathway, targeting TGF-β simultaneously could block dysregulated tissue remodelling in TSC tumours.

Topics: Angiofibroma; Cells, Cultured; Extracellular Signal-Regulated MAP Kinases; Fibroblasts; Humans; Immunohistochemistry; Matrix Metalloproteinase 2; Polymerase Chain Reaction; Proto-Oncogene Proteins c-akt; Transforming Growth Factor beta; Tuberous Sclerosis

Juvenile nasopharyngeal angiofibroma (JNA) is a highly vascular and locally invasive tumor that exclusively affects male adolescents. Sex hormones are first discussed to clarify the etiology of JNA. Recently with the advances in the field of cell biology angiogenetic markers, proliferation markers and growth factors are investigated to identify the molecular basis of JNA as all neoplasm. In this study we tried to evaluate the expression of proliferation, angiogenesis and hormonal markers in JNA.. Immunohistochemical analysis were performed on paraffin-embedded 27 JNA samples which were obtained from the patients operated at University of Hacettepe Department of Otorhinolaryngology, a tertiary care center. Estrogen receptor (ER), progesterone receptor (PR), proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-beta) specific antibodies were used and evaluated by light microscopy. Two of 27 cases were ER positive. Nine of 27 cases were positive for PR. All of the cases were stained with PCNA. Twenty-four of 27 cases stained with VEGF. TGF-beta was positive in 14 of 27 cases. All recurrent cases were stained with PCNA and VEGF; just three of them were stained with TGF-beta.. Hormonal markers ER and PR did not seem to play a role in pathogenesis of JNA. PCNA, VEGF and TGF-beta may play a role in the pathogenesis of JNA by promoting angiogenesis and proliferation, but this role did not seem to have a relation with hormonal markers.

Topics: Adolescent; Adult; Angiofibroma; Child; Female; Humans; Immunohistochemistry; Male; Nasopharyngeal Neoplasms; Neoplasm Recurrence, Local; Proliferating Cell Nuclear Antigen; Receptors, Estrogen; Receptors, Progesterone; Retrospective Studies; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Despite their benign histological appearance, juvenile angiofibromas sometimes exhibit an aggressive growth behavior. Molecular and genetic analyses have detected beta-catenin mutations and androgen receptor gene gains in this tumor. Because intensive cross-talk among beta-catenin, androgen receptor, and C-MYC has been detected recently, we analyzed expression of the C-MYC protooncogene (MYC) on the genetic, transcriptional and translational level in seven sporadic juvenile angiofibromas. Two-color in situ hybridization analyses for chromosome 8 and MYC found in all seven juvenile angiofibromas significant MYC losses. In the three advanced juvenile angiofibromas of this series (Fisch stages III and IV) additional significant MYC gains were observed demonstrating a genetic heterogeneity for the MYC protooncogene. In cases of genetic MYC heterogeneity, reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, Western blot investigations, and immunohistology showed increased C-MYC mRNA and protein levels. Semiquantitative RT-PCR analyses from laser microdissected endothelial cells and fibroblasts found no differences of C-MYC mRNA levels, leaving open the question of the neoplastic cell in juvenile angiofibromas. The finding of genetic MYC heterogeneity associated with C-MYC overexpression on the mRNA and protein level in advanced juvenile angiofibromas indicates involvement of the MYC oncogene in aggressive growth behavior.

Topics: Angiofibroma; beta Catenin; Genes, myc; Genetic Heterogeneity; Humans; Proto-Oncogene Proteins c-myc; Receptors, Androgen; RNA, Messenger; Transforming Growth Factor beta

Juvenile nasopharyngeal angiofibroma is a rare nasopharyngeal tumor that occurs exclusively in adolescent boys. It is a histologically benign but locally persistent growth of stromal and vascular tissue. Although male hormones and some growth factors, such as transforming growth factor beta1 (TGF-beta1), insulin-like growth factor II (IGF-II), and, lately, the proto-oncogene beta-catenin, have been implicated in the histogenesis of the tumor, the biologic signaling pathways that drive this peculiar fibrovascular proliferation are still nuclear.. To evaluate immunoexpressions of beta-catenin, c-Kit, p130Cas, TGF-beta3, bone morphogenic protein 4, nerve growth factor (NGF), and the IGF receptor (IGF-1R) in a series of juvenile nasopharyngeal angiofibromas and to compare to that of a group of nasal polyps.. A standard immunohistochemical technique was used on paraffin sections of 12 sporadic juvenile nasopharyngeal angiofibromas and 15 nasal polyps with microwave or steam antigen retrieval. Immunoreactivity was analyzed semiquantitatively in stromal cells and endothelial cells of each case.. The expressions of beta-catenin (nuclear), c-Kit (cytoplasmic), and NGF (cytoplasmic) were higher and more frequent in stromal cells of juvenile nasopharyngeal angiofibromas than those of nasal polyps. Both juvenile nasopharyngeal angiofibromas and nasal polyps showed similarly frequent and strong immunoreactivity for p130Cas and TGF-beta3 and weak immunoreactivity for bone morphogenic protein 4 in both stromal cells and endothelial cells. No IGF-1R immunoreactivity was detected in any case of either group.. Our results support the role of beta-catenin in juvenile nasopharyngeal angiofibromas and suggest a potential involvement of c-Kit and NGF signaling pathways in the juvenile nasopharyngeal angiofibromas. Although the biologic significance of c-Kit in juvenile nasopharyngeal angiofibromas has yet to be defined, the finding of frequent and high c-Kit expression might have therapeutic importance for patients with juvenile nasopharyngeal angiofibromas.

Topics: Adolescent; Adult; Angiofibroma; Antigens, Surface; Bone Morphogenetic Proteins; Child; Crk-Associated Substrate Protein; Growth Substances; Humans; Immunohistochemistry; Male; Nasal Polyps; Nasopharyngeal Neoplasms; Nerve Growth Factor; Paraffin Embedding; Phosphoproteins; Proteins; Proto-Oncogene Mas; Proto-Oncogene Proteins c-kit; Receptor, IGF Type 1; Receptors, Progesterone; Retinoblastoma Protein; Retinoblastoma-Like Protein p130; Transforming Growth Factor beta; Transforming Growth Factor beta3

Tuberous sclerosis complex (TSC) is an autosomal dominantly inherited disorder associated with an alteration of the TSC2 tumor suppressor gene which encodes for the protein product tuberin. The disease is characterized by the development of hamartomas, e.g. cutaneous angiofibromas which consist of vascular cells, interstitial cells, and normal components of the skin. The Eker rat model, an animal model of inherited cancer, has been shown to carry a mutation of TSC2.. Immunohistochemical analyses of human angiofibromas were performed using antibodies directed against tuberin and angiogenic growth factors. Proliferation of human dermal microvascular endothelial cells (HDMEC) was determined after incubation with the supernatants of TSC2 (+/+) and TSC2 (-/-) rat embryonic fibroblasts (REF) that were derived from the Eker strain.. Loss of the expression of tuberin was observed in the interstitial cells of 13 of 39 angiofibromas. The expression of tuberin was retained in the vascular cells. In all analyzed angiofibromas, the angiogenic factors bFGF, PD-ECGF, VEGF and angiogenin were detected in the interstitial cells and/or vascular cells. Expression of PDGF-B and TGF-beta1 was weak. Tissue culture supernatants from TSC2 (-/-) REF stimulated the growth of HDMEC significantly more than supernatants from TSC2 (+/+) REF.. A functional loss of tuberin may stimulate vascular growth.

Topics: Angiofibroma; Animals; Cells, Cultured; Culture Media, Conditioned; Endothelial Growth Factors; Endothelium; Fibroblast Growth Factor 2; Fibroblasts; Humans; Immunohistochemistry; Lymphokines; Neovascularization, Pathologic; Proto-Oncogene Proteins c-sis; Rats; Rats, Mutant Strains; Repressor Proteins; Ribonuclease, Pancreatic; Thymidine Phosphorylase; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tuberous Sclerosis; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; Vascular Neoplasms

Juvenile nasopharyngeal angiofibroma (JNA) is a histologically benign, locally aggressive neoplasm of the nasopharynx that exclusively affects male adolescents. It is known to be sensitive to androgens, but there are likely intermediary cytokines and/or growth factors that mediate aggressive stromal cell proliferation and angiogenesis. Transforming growth factor beta1 (TGF-beta1) is a polypeptide that is secreted in an inactive form, cleaved to produce an active form, and then deactivated in the tissues. It activates fibroblast proliferation and is known to induce angiogenesis.. To evaluate the presence of activated TGF-beta1 within the stroma of JNA specimens and to quantify the percentage of JNA specimens expressing the active growth factor.. Immunohistochemical analysis was performed on 19 specimens of JNA using a unique antibody that identifies only the activated form of TGF-beta1. The percentage of cells staining positively for activated TGF-beta1 was determined semiquantitatively by visual methods.. Of 19 cases stained, all 19 (100%) showed strong positive staining (2 cases with 33%-66% of cells staining and 17 with 66%-100% of cells staining). Activated TGF-beta1 was identified in stromal cell nuclei and cytoplasm and in the endothelium of the capillaries within all specimens of JNA.. The localization of activated TGF-beta1 to the fibroblasts and endothelial cells within JNA tumors suggests that TGF-beta1 may play a role in the stromal cell proliferation and angiogenesis associated with JNA. Additional receptor studies and more quantitative methods of analysis are needed to further define the role of TGF-beta1 in the pathogenesis of JNA.

Topics: Adolescent; Angiofibroma; Humans; Immunohistochemistry; Male; Nasopharyngeal Neoplasms; Transforming Growth Factor beta