Transforming Growth Factor-β Receptor Type Research Articles

Methylation Silencing of Transforming Growth Factor-β Receptor Type II in Rat Prostate Cancers

To identify methylation-silenced genes in prostate cancers, a microarray analysis for genes up-regulated by treatment with a demethylating agent, 5-aza-2'-deoxycytidine, was performed using three rat prostate cancer cell lines. Eight genes (Aebp1, Dysf, Gas6, LOC361288, Nnat, Ocm, RGD1308119, and Tgfbr2) were re-expressed at 16-fold or more, and their promoter CpG islands were shown to be densely methylated in the cancer cell lines. From the eight genes, Tgfbr2, a key mediator of transforming growth factor-beta (TGF-beta) signaling that has been strongly implicated in human and rat prostate carcinogenesis, was selected, and its silencing in primary samples was analyzed further. Tgfbr2 was methylated and markedly down-regulated in three of seven 3,2'-dimethyl-4-aminobiphenyl-induced invasive adenocarcinomas in the dorsolateral lobe of the rat prostate. In humans, marked down-regulation of TGFBR2 protein was observed in 12 of 20 high-grade prostatic intraepithelial neoplasia and 36 of 60 prostate cancers. DNA methylation of the human TGFBR2 promoter CpG islands repressed transcription, if present, but neither methylation nor mutation were detected in 27 human prostate cancers analyzed. Methylation silencing of rat Tgfbr2 was associated with histone H3 lysine 9 trimethylation, whereas decreased expression of human TGFBR2 was mainly due to decreased transcription activity, sometimes in concert with histone deacetylation and H3 lysine 27 trimethylation. The identification of methylation silencing of Tgfbr2 in rat prostate cancers, in accordance with TGFBR2 down-regulation in human prostate cancers, will enable us to analyze how aberrant methylation is induced in vivo and identify factors that promote and suppress the induction of aberrant methylation.

Optimization of a Dihydropyrrolopyrazole Series of Transforming Growth Factor-β Type I Receptor Kinase Domain Inhibitors: Discovery of an Orally Bioavailable Transforming Growth Factor-β Receptor Type I Inhibitor as Antitumor Agent

In our continuing effort to expand the SAR of the quinoline domain of dihydropyrrolopyrazole series, we have discovered compound 15d, which demonstrated the antitumor efficacy with oral bioavailability. This effort also demonstrated that the PK/PD in vivo target inhibition paradigm is an effective approach to assess potential for antitumor efficacy. The dihydropyrrolopyrazole inhibitor 15d (LY2109761) is representative of a novel series of antitumor agents.

Epidermal growth factor up-regulates transforming growth factor-β receptor type II in human dermal fibroblasts via p38 mitogen-activated protein kinase pathway

TGF-β receptors (TβRs) are serine/threonine kinase receptors that bind to TGF-β and propagate intracellular signaling through Smad proteins. TβRs are repressed in some human cancers and expressed at high levels in several fibrotic diseases. We demonstrated that epidermal growth factor (EGF) up-regulates type II TGF-β receptor (TβRII) expression in human dermal fibroblasts. EGF-mediated induction of TβRII expression was inhibited by the treatment of fibroblasts with a specific p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, whereas MEK inhibitor PD98059 did not block the up-regulation of TβRII by EGF. EGF induced the TβRII promoter activity, and this induction was significantly blocked by SB203580, but not by PD98059. The overexpression of the dominant negative form of p38α or p38β significantly reduced the induction of TβRII promoter activity by EGF. These results indicate that the EGF-mediated induction of TβRII expression involves the p38 MAPK signaling pathway. The EGF-mediated induction of TβRII expression may participate in a synergistic interplay between EGF and TGF-β signaling pathway.

Mutations in Transforming Growth Factor-β Receptor Type II Cause Familial Thoracic Aortic Aneurysms and Dissections

A genetic predisposition for progressive enlargement of thoracic aortic aneurysms leading to type A dissection (TAAD) is inherited in an autosomal-dominant manner in up to 19% of patients, and a number of chromosomal loci have been identified for the condition. Having mapped a TAAD locus to 3p24-25, we sequenced the gene for transforming growth factor-beta receptor type II (TGFBR2) to determine whether mutations in this gene resulted in familial TAAD. We sequenced all 8 coding exons of TGFBR2 by using genomic DNA from 80 unrelated familial TAAD cases. We found TGFBR2 mutations in 4 unrelated families with familial TAAD who did not have Marfan syndrome. Affected family members also had descending aortic disease and aneurysms of other arteries. Strikingly, all 4 mutations affected an arginine residue at position 460 in the intracellular domain, suggesting a mutation "hot spot" for familial TAAD. Despite identical mutations in the families, assessment of linked polymorphisms suggested that these families were not distantly related. Structural analysis of the TGFBR2 serine/threonine kinase domain revealed that R460 is strategically located within a highly conserved region of this domain and that the amino acid substitutions resulting from these mutations will interfere with the receptor's ability to transduce signals. Germline TGFBR2 mutations are responsible for the inherited predisposition to familial TAAD in 5% of these cases. Our results have broad implications for understanding the role of TGF-beta signaling in the pathophysiology of TAAD.

Treatment of Aortic Disease in Patients With Marfan Syndrome

Marfan syndrome (MFS) is a heritable disorder of the connective tissue with a prevalence of ≈1 in 3000 to 5000 individuals. The condition is inherited in an autosomal dominant manner with complete penetrance but demonstrates variable expression with significant intra- and interfamilial variation. Approximately 25% of patients do not have a family history and represent sporadic, new mutations for the condition. The cardinal features of MFS involve the cardiovascular, ocular, and skeletal systems. The most life-threatening complication of MFS is thoracic aortic aneurysms leading to aortic dissection, rupture, or both. This article focuses on medical and surgical treatment of aortic disease in patients with MFS and addresses the treatment of aortic disease in children and pregnant women with the condition. The most common cardiovascular complication in patients with MFS is progressive aortic root enlargement initially occurring at the sinuses of Valsalva. Ascending aortic aneurysm can precipitate acute type A aortic dissection, aortic rupture, aortic regurgitation (AR), or all 3, and these complications were the primary cause of death before the advent of successful preventive therapies. Treatment of the aorta consists of regular imaging to detect and quantify progression of aortic dilation, β-adrenergic receptor antagonist therapy, and prophylactic aortic repair when the dilation reaches a sufficient size to threaten dissection or cause AR. Before the era of open-heart surgery, the majority of patients with MFS died prematurely of rupture of the aorta, with an average life expectancy of 45 years.1 The success of current medical and surgical treatment of aortic disease in MFS has substantially improved the average life expectancy, extending it up to 70 years.2,3 Cardiovascular manifestations in MFS also include valvular disease involving the mitral valve, aortic valve, or both. Mitral valve prolapse is the most prevalent valvular abnormality, affecting 35% to 100% of patients.4 Mitral …

A Broader Role for β-Arrestins

β-Arrestins are multifunctional proteins that desensitize heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors and help link such receptors to cellular signaling pathways, as well as promote endocytosis of the receptors. In two reports, Chen et al. (see the Perspective by Spiegel) show that β-arrestins are even more versatile than previously thought. β-arrestin 2 is required to promote internalization of Frizzled proteins (the cell surface receptors for Wnt glycoproteins). In this role, β-arrestins do not bind directly to receptors, as they do with G protein-coupled receptors. Rather, β-arrestin 2 binds to a protein called disheveled (Dvl) that is recruited to activated Frizzled receptor proteins in the cell membrane. Once Dvl brings β-arrestin to Frizzled receptor protein complexes, the receptors are recruited into clathrin-coated pits for internalization. β-arrestins also promote internalization of a completely different type of receptor, the transforming growth factor-β receptor type III. In this case, β-arrestin binds to a receptor subunit that is phosphorylated by another receptor subunit. W. Chen, D. ten Berge, J. Brown, S. Ahn, L. A. Hu, W. E. Miller, M. G. Caron, L. S. Barak, R. Nusse, R. J. Lefkowitz, Dishevelled 2 recruits β-arrestin 2 to mediate Wnt5A-stimulated endocytosis of Frizzled 4. Science 301 , 1391-1394 (2003). [Abstract] [Full Text] W. Chen, K. C. Kirkbride, T. How, C. D. Nelson, J. Mo, J. P. Frederick, X.-F. Wang, R. J. Lefkowitz, G. C. Blobe, β-Arrestin 2 mediates endocytosis of type III TGF-β receptor and down-regulation of its signaling. Science 301 , 1394-1397 (2003). [Abstract] [Full Text] A. Spiegel, ß-Arrestin--Not just for G protein-coupled receptors. Science 301 , 1338-1339 (2003). [Summary] [Full Text]

Microsatellite mutations of transforming growth factor-β receptor type II and caspase-5 occur in human precursor T-cell lymphoblastic lymphomas/leukemias in vivo but are not associated with hMSH2 or hMLH1 promoter methylation

In solid cancers, defective DNA mismatch repair (MMR) is most commonly caused by hMSH2 or hMLH1 mutations, or epigenetic silencing of hMLH1 by promoter hypermethylation, and results in the acquisition of characteristic frameshift microsatellite mutations of mononucleotide repeats located within the coding regions of defined target genes. We previously identified hMSH2 mutations in T-cell lymphoblastic lymphoma (T-LBL) patient tumor samples and others have reported coding region microsatellite mutations in T-cell acute lymphoblastic leukemia (T-ALL) cell lines. Thus, while MMR gene mutations are known to occur in some human T-lymphoblastic tumors in vivo, it is still unknown if the coding region microsatellite mutations detected in human cell lines also occur in vivo or if hMLH1 or hMSH2 promoter hypermethylation contributes to defective MMR in these tumors. We analyzed the TGFβRII (A)10 and caspase-5 (A)10 coding region repeats in 16 human T-LBL/ALL patient tumor samples and identified six with microsatellite mutations in one or both repeats. There was no evidence of hMSH2 or hMLH1 promoter methylation as assessed by standard methylation specific PCR or by a novel temporal temperature gradient electrophoresis (TTGE) method that analyzed 25 and 30 CpG sites in the hMLH1 and hMSH2 promoters, respectively. Our results indicate that coding region microsatellite mutations characteristic of defective MMR occur in some human T-LBL/ALL in vivo but not as a consequence of hMLH1 or hMSH2 promoter hypermethylation. Furthermore, the identification of TGFβRII and caspase-5 coding region mutations in vivo implicates these genes in the pathogenesis of human T-LBL/ALL.

Absence of Microsatellite Instability and Germline Mutations of E-Cadherin, APC and p53 Genes in Japanese Familial Gastric Cancer

To evaluate the genetic factors of familial predisposition to gastric cancer, genetic alterations in the surgically resected stomach samples from gastric-cancer-prone families were investigated. Familial gastric cancer (FGC) was defined as gastric cancer occurring in a family with 3 or more gastric cancer patients over at least two successive generations. We examined replication error (RER) of six microsatellite markers and screened mutations of the 10-(A) repeat sequence in the transforming growth factor-β receptor type II (TGF-βRII) gene in individuals from seven unrelated FGC families. Three cases showed RER at one of the six (CA)n microsatellite markers but the other 4 cases showed no RER at any of these loci. No mutation was found in the 10-(A) repeat of the TGF-βRII gene. Additionally, no germline mutation was found by polymerase chain reaction-single strand conformation polymorphism in exons 1–16 of E-cadherin, exons 5–8 of p53 and in the mutation cluster region of APC. These results indicate that disorders in the DNA mismatch repair system, E-cadherin, p53 and APC may be infrequently involved in the carcinogenesis of Japanese FGC.

Ligand-independent oligomerization of cell-surface erythropoietin receptor is mediated by the transmembrane domain.

Binding of erythropoietin (Epo) to the Epo receptor (EpoR) is crucial for production of mature red cells. Although it is well established that the Epo-bound EpoR is a dimer, it is not clear whether, in the absence of ligand, the intact EpoR is a monomer or oligomer. Using antibody-mediated immunofluorescence copatching (oligomerizing) of epitope-tagged receptors at the surface of live cells, we show herein that a major fraction of the full-length murine EpoR exists as preformed dimers/oligomers in BOSC cells, which are human embryo kidney 293T-derived cells. This observed oligomerization is specific because, under the same conditions, epitope-tagged EpoR did not oligomerize with several other tagged receptors (thrombopoietin receptor, transforming growth factor beta receptor type II, or prolactin receptor). Strikingly, the EpoR transmembrane (TM) domain but not the extracellular or intracellular domains enabled the prolactin receptor to copatch with EpoR. Preformed EpoR oligomers are not constitutively active and Epo binding was required to induce signaling. In contrast to tyrosine kinase receptors (e.g., insulin receptor), which cannot signal when their TM domain is replaced by the strongly dimerizing TM domain of glycophorin A, the EpoR could tolerate the replacement of its TM domain with that of glycophorin A and retained signaling. We propose a model in which TM domain-induced dimerization maintains unliganded EpoR in an inactive state that can readily be switched to an active state by physiologic levels of Epo.

Microsatellite Instability of Endothelial Cell Growth and Apoptosis Genes Within Plexiform Lesions in Primary Pulmonary Hypertension

Primary pulmonary hypertension (PPH) is a frequently fatal disease whose pathobiology is poorly understood. Monoclonal endothelial cell growth is present within plexiform lesions of patients with PPH but not secondary PH because of congenital heart malformations. We hypothesized that endothelial cells within PPH plexiform lesions harbor mutations permissive for clonal cell growth. We found that endothelial cells in PPH plexiform lesions demonstrated microsatellite instability within the human MutS Homolog 2 gene (10 of 20 lesions) and displayed microsatellite site mutations and reduced protein expression of transforming growth factor-beta receptor type II (6 of 19 lesions) and Bax (4 of 19 lesions). These results suggest that, in PPH, proliferated endothelial cells have genetic alterations associated with microsatellite instability and concomitant perturbation of growth and apoptosis gene expression akin to neoplasia. The full text of this article is available at http://www.circresaha.org.

A dominant negative mutation of transforming growth factor-beta receptor type II gene in microsatellite stable oesophageal carcinoma.

Recent investigations revealed microsatellite instability in colon cancers are associated with mutations of the transforming growth factor-β receptor type II gene (TGF-β RII) that encodes a transmembrane protein containing an intracellular serine/threonine kinase domain. Activation of TGF-β receptor type I (RI) and RII by TGF-β induces nuclear translocation of Smad proteins including Smad2 and Smad4 that have been originally identified as tumour suppressor genes. We have previously reported six cases with microsatellite instability in 32 oesophageal carcinomas. In this study, we analysed genetic mutations of TGF-β RII, Smad2 and Smad4 in these oesophageal carcinoma tissues and established 16 cell lines. No genetic mutation was detected in any tissues or cell lines except one tissue sample of microsatellite stable oesophageal carcinoma, that is, a mis-sense mutation of glutamic acid to glutamine at codon 526 (E526Q) in the TGF-β RII serine/threonine kinase domain. Interestingly, the mutant TGF-β RII E526Q can completely inhibit TGF-β-induction of nuclear translocation of Smad4 protein in oesophageal carcinoma cells. This mutation of TGF-β RII that is not associated with microsatellite instability might make a dominant negative effect on TGF-β signal transduction in oesophageal carcinoma. © 2000 Cancer Research Campaign

The Role of Sp1 in the Differential Expression of Transforming Growth Factor-β Receptor Type II in Human Breast Adenocarcinoma MCF-7 Cells

Progression of MCF-7 cells from early passage (MCF-7E, <200 passage) to late passage (MCF-7L, >500 passage) correlates with a loss of sensitivity to exogenous TGFbeta1. We have previously shown that loss of TGFbeta sensitivity is due to decreased expression of the transforming growth factor receptor type II (TbetaRII) and is associated with increased tumorigenicity in nude mice. Reduced TbetaRII expression in MCF-7L cells is caused by decreased TbetaRII promoter activity in this cell line. Our previous studies using 5' deletion constructs of this promoter revealed that MCF-7L cells were unable to support transcription of the minimal promoter (-47 to +2) to the same levels as the MCF-7E cells. This region of the promoter contains an Sp1 element at position -25 from the major transcription start site. In this study, we investigated the role of Sp1 in TbetaRII transcription. Mutation of the Sp1 site resulted in decreased transcription of TbetaRII in MCF-7E and MCF-7L cells, indicating that this site played a role in transcription of this promoter. Gel shift assays using the proximal Sp1 site from the TbetaRII promoter showed enhanced DNA:protein complex formation with nuclear proteins isolated from MCF-7E cells compared with MCF-7L cells. Supershift analysis identified this binding activity as Sp1. Western blot analysis of Sp1 levels demonstrated that MCF-7E cells contain increased Sp1 protein compared with MCF-7L cells, paralleling the increased binding activity. Differential Sp1 activity was also demonstrated by higher levels of transcription of an Sp1-dependent insulin-like growth factor II promoter construct in MCF-7E cells compared with MCF-7L cells. Co-transfection of an Sp1 expression vector with a TbetaRII promoter construct in MCF-7L cells induced the expression from the promoter-CAT constructs and resulted in an increase of endogenous TbetaRII protein levels. These results demonstrate that the transcriptional repression of TbetaRII in MCF-7L cells is caused, in part, by lower Sp1 levels.

Lack of frameshift mutations at coding mononucleotide repeats in hepatocellular carcinoma in Japanese patients

BACKGROUND Microsatellite instability occurs frequently in hereditary nonpolyposis colorectal carcinoma, in sporadic gastrointestinal carcinoma, and in other tumors. In these tumors, slippage-related frameshift mutations have been detected at coding mononucleotide repeats in genes such as those for transforming growth factor-β receptor type II (TGFβRII), mannose 6-phosphate/insulinlike growth factor II receptor (M6P/IGFIIR), hMSH3, hMSH6, and Bcl-2–associated X protein (BAX). Because these genes regulate cell growth or repair DNA mismatches, loss of their function is thought to promote tumor development. The authors screened for these frameshift mutations and investigated the incidence of microsatellite instability (MI) in hepatocellular carcinoma (HCC) in Japan. METHODS Fifty HCC samples were analyzed in this study. The authors used polymerase chain reactions to screen for frameshift mutation at the TGFβRII (A)10 tract, the M6P/IGFIIR (G)8 tract, the hMSH3 (A)8 tract, the hMSH6 (C)8 tract, and the BAX (G)8 tract. For MI analysis, matched tumor and nontumor liver DNA were investigated with respect to 10 microsatellite loci. RESULTS No frameshift mutation was detected in any case, and only 4% of these cancers exhibited MI in comparisons between tumor and nontumor liver specimens. CONCLUSIONS This study suggests that frameshift mutation at coding mononucleotide repeats within TGFβRII, M6P/IGFIIR, hMSH3, hMSH6, and BAX genes did not seem to be involved in hepatocarcinogenesis in the Japanese population studied. Cancer 2000;88:1025–9. © 2000 American Cancer Society.

Genomic instability and colorectal cancer

Colon cancer results from the accumulation of genetic alterations. Genomic instability creates a permissive state in which a potential cancer cell is allowed to acquire enough mutations to become a cancer cell. Several forms of genomic instability are common in colon cancer: microsatellite instability (MSI), chromosome instability (CIN), and chromosome translocations. MSI occurs in approximately 15% of colon cancers and results from inactivation of the mutation mismatch repair (MMR) system secondary to either MMR gene mutations or hypermethylation of the hMLH1 promoter. It promotes tumorigenesis by generating mutations in target genes that possess coding microsatellite repeats, such as the transforming growth factor-beta receptor type II gene. CIN occurs in most other colon cancers and leads to a different pattern of gene alterations that culminate in tumor formation. It seems to result from mutations in genes that control mitosis, DNA damage repair, centrosome structure and function, and other fundamental processes in DNA replication. The clinical significance of genomic instability is now under investigation, and it is hoped that this research will soon yield results that have an immediate effect on the treatment of colon cancer.

Possible involvement of transforming growth factor-β1 and transforming growth factor-β receptor type II during luteinization in the marmoset ovary

The expression of transforming growth factor-β1 (TGF-β1), and transforming growth factor-β receptor type II (TβR-II), were evaluated in periovulatory marmoset ovaries. Histochemical methods were used, in particular double-labelling techniques, in order to correlate growth factor/receptor expression with proliferation (Ki 67), apoptosis (TUNEL method) and luteinization (3β-hydroxysteroid dehydrogenase (3β-HSD)). The latter was used as a luteinization marker. Periovulatory ovaries are especially suited for studying all aspects since they typically consist of small non-luteinized follicles, large luteinizing follicles and corpora lutea accessoria (Clas), which have developed from large luteinizing follicles. TGF-β1 and TβR-II expression was found in luteinizing theca cells of large periovulatory follicles and in all luteal cells of Clas. Non-luteinized theca cells, including those of small follicles were always devoid of any immunostaining. Granulosa cells of small follicles were immunopositive for TβR-II. Large follicles with granulosa cell immunoreactivity of both antibodies coexisted with non-reactive follicles of comparable size. The highest activity of the luteal marker enzyme 3β-HSD was co-localized in the same cells that expressed TGF-β1 and TβR-II. The double-labelling experiments revealed that TGF-β1 and TβR-II expression is not correlated with proliferation or apoptosis of follicular cells. Our results indicate that TGF-β1 and TβR-II participate in differentiation processes, i.e. luteinization, rather than proliferation. In particular, the dynamics of TβR-II expression appear highly related to the process of luteinization.

Induction of Transforming Growth Factor-β Receptor Type II Expression in Estrogen Receptor-positive Breast Cancer Cells through SP1 Activation by 5-Aza-2′-deoxycytidine

Previous studies suggest that estrogen receptor-positive (ER+) breast cancer cells acquire resistance to transforming growth factor-beta (TGF-beta) because of reduced expression levels of TGF-beta receptor type II (RII). We now report that treatment of ER+ breast cancer cells with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-2'-dC) leads to accumulation of RII transcript and protein in three different cell lines. RII induction restored TGF-beta response in MCF-7L breast cancer cells as indicated by the enhanced activity of a TGF-beta responsive promoter-reporter construct (p3TP-Lux). A transiently transfected RII promoter-reporter element (RII-chloramphenicol acetyltransferase) showed an increase in activity in the 5-aza-2'-dC-treated MCF-7L cells compared with untreated cells, suggesting the activation of a transactivator of RII transcription. Using electrophoretic mobility shift assays, the enhanced binding of proteins from 5-aza-2'-dC-treated MCF-7L nuclear extracts to radiolabeled Sp1 oligonucleotides was demonstrated. An RII promoter-chloramphenicol acetyltransferase construct containing a mutation in the Sp1 site was not expressed in the 5-aza-2'-dC-treated MCF-7L cells, further demonstrating that induction of Sp1 activity by 5-aza-2'-dC in the MCF-7L cells was critical to RII expression. Northern analysis indicated that 5-aza-2'-dC treatment did not affect the Sp1 transcript levels. Western blot analysis revealed an increase of Sp1 protein in the 5-aza-2'-dC-treated MCF-7L cells, but there was no change in the c-Jun levels. Studies after cyclohexamide treatment suggested an increase in the Sp1 protein stability from the 5-aza-2'-dC-treated MCF-7L extracts compared with untreated control extracts. These results indicate that the transcriptional repression of RII in the ER+ breast cancer cells is caused by suboptimal activity of Sp1, whereas treatment with 5-aza-2'-dC stabilizes the protein thus increasing steady-state Sp1 levels and thereby leads to enhanced RII transcription and subsequent restoration of TGF-beta sensitivity.

Microsatellite instability and mutations of transforming growth factor-β receptor type II gene in hepatocellular carcinoma

Microsatellite instability and mutations of transforming growth factor-β receptor type II gene in hepatocellular carcinoma

Transforming Growth Factor-β Receptor Type I and Type II Expression During Murine Hair Follicle Development and Cycling

Although the TGF-beta family of growth factors probably regulates skin and hair follicle development, its exact role is still quite ill-defined. Here, we characterize the correlative expression pattern of the interdependent high affinity receptor proteins for TGF-beta1 and TGF-beta3, TGF-beta receptor type I (TGF-betaRI) and TGF-beta receptor type II (TGF-betaRII), during hair follicle development and cycling in C57BL/6 mice. During neonatal follicle development, TGF-betaRII immunoreactivity is confined to epithelial cells. Focal epidermal TGF-betaRII expression is seen even before actual hair placode formation. In contrast to the TGF-betaRII immunoreactivity in the outer root sheath, precortical hair matrix and inner root sheath cells were TGF-betaRII negative during hair bulb morphogenesis. TGF-betaRI (Alk-5) immunoreactivity largely overlapped the TGF-betaRII expression pattern, but was more widespread. During hair follicle cycling in adolescent mice, TGF-betaRII immunoreactivity was restricted to follicles, and was strikingly hair cycle dependent (maximal immunoreactivity: anagen VI and early catagen). Again, TGF-betaRI (Alk-5) immunoreactivity co-localized with TGF-betaRII immunoreactivity, but was more extensive. Reverse transcriptase polymerase chain reaction analysis of TGF-betaRII mRNA confirmed peak transcript levels in back skin with most hair follicles in the anagen VI-catagen transformation. mRNA levels of TGF-betaRI (Alk-5) did not vary significantly during the hair cycle, whereas those of TGF-betaRI (threonine-serine kinase 7 L) declined during early anagen, and were maximal during the anagen-catagen transition. This provides a basis for defining the choreography of TGF-beta-related signalling during hair follicle morphogenesis and cycling, introduces intraepidermal TGF-betaRII immunoreactivity as a marker for imminent follicle development, and supports the concept that both TGF-betaRII and TGF-betaRI stimulation is involved in, but not restricted to, the control of catagen induction.

Expression of transforming growth factor-β receptor type II gene in gastric cancer cell lines

Expression of transforming growth factor-β receptor type II gene in gastric cancer cell lines