Genomic profiling identifies alterations in TGFbeta signaling through loss of TGFbeta receptor expression in human renal cell carcinogenesis and progression

Design and characterization of a novel tumor-homing cell-penetrating peptide for drug delivery in TGFBR3 high-expressing tumors

Targeted therapy has attracted more and more attention in cancer treatment in recent years. However, due to the diversity of tumor types and the mutation of target sites on the tumor surface, some existing targets are no longer suitable for tumor therapy. In addition, the long-term administration of a single targeted drug can also lead to drug resistance and attenuate drug potency, so it is important to develop new targets for tumor therapy. The expression of Type III transforming growth factor β receptor (TGFBR3) is upregulated in colon, breast, and prostate cancer cells, and plays an important role in the occurrence and development of these cancers, so TGFBR3 may be developed as a novel target for tumor therapy, but so far there is no report on this research. In this study, the structure of bone morphogenetic protein 4 (BMP4), one of the ligands of TGFBR3 was analyzed through the docking analysis with TGFBR3 and sequence charge characteristic analysis, and a functional tumor-targeting penetrating peptide T3BP was identified. The results of fluorescent labeling experiments showed that T3BP could target and efficiently enter tumor cells with high expression of TGFBR3, especially A549 cells. When the expression of TGFBR3 on the surface of tumor cells (HeLa) was knocked down by RNA interference, the high delivery efficiency of T3BP was correspondingly reduced by 40%, indicating that the delivery was TGFBR3-dependent. Trichosanthin (TCS, a plant-derived ribosome inactivating protein) fused with T3BP can enhance the inhibitory activity of the fusion protein on A549 cells by more than 200 times that of TCS alone. These results indicated that T3BP, as a novel targeting peptide that can efficiently bind TGFBR3 and be used for targeted therapy of tumors with high expression of TGFBR3. This study enriches the supply of tumor-targeting peptides and provides a new potential application option for the treatment of tumors with high expression of TGFBR3.

Inflammatory Networks in Renal Cell Carcinoma

Cancer-associated inflammation has been established as a hallmark feature of almost all solid cancers. Tumor-extrinsic and intrinsic signaling pathways regulate the process of cancer-associated inflammation. Tumor-extrinsic inflammation is triggered by many factors, including infection, obesity, autoimmune disorders, and exposure to toxic and radioactive substances. Intrinsic inflammation can be induced by genomic mutation, genome instability and epigenetic remodeling in cancer cells that promote immunosuppressive traits, inducing the recruitment and activation of inflammatory immune cells. In RCC, many cancer cell-intrinsic alterations are assembled, upregulating inflammatory pathways, which enhance chemokine release and neoantigen expression. Furthermore, immune cells activate the endothelium and induce metabolic shifts, thereby amplifying both the paracrine and autocrine inflammatory loops to promote RCC tumor growth and progression. Together with tumor-extrinsic inflammatory factors, tumor-intrinsic signaling pathways trigger a Janus-faced tumor microenvironment, thereby simultaneously promoting or inhibiting tumor growth. For therapeutic success, it is important to understand the pathomechanisms of cancer-associated inflammation, which promote cancer progression. In this review, we describe the molecular mechanisms of cancer-associated inflammation that influence cancer and immune cell functions, thereby increasing tumor malignancy and anti-cancer resistance. We also discuss the potential of anti-inflammatory treatments, which may provide clinical benefits in RCCs and possible avenues for therapy and future research.

TGF-β signaling pathway: Therapeutic targeting and potential for anti-cancer immunity

Transforming growth factor-β (TGFβ) is a pleiotropic secretory cytokine exhibiting both cancer-inhibitory and promoting properties. It transmits its signals via Suppressor of Mother against Decapentaplegic (SMAD) and non-SMAD pathways and regulates cell proliferation, differentiation, invasion, migration, and apoptosis. In non-cancer and early-stage cancer cells, TGFβ signaling suppresses cancer progression via inducing apoptosis, cell cycle arrest, or anti-proliferation, and promoting cell differentiation. On the other hand, TGFβ may also act as an oncogene in advanced stages of tumors, wherein it develops immune-suppressive tumor microenvironments and induces the proliferation of cancer cells, invasion, angiogenesis, tumorigenesis, and metastasis. Higher TGFβ expression leads to the instigation and development of cancer. Therefore, suppressing TGFβ signals may present a potential treatment option for inhibiting tumorigenesis and metastasis. Different inhibitory molecules, including ligand traps, anti-sense oligo-nucleotides, small molecule receptor-kinase inhibitors, small molecule inhibitors, and vaccines, have been developed and clinically trialed for blocking the TGFβ signaling pathway. These molecules are not pro-oncogenic response-specific but block all signaling effects induced by TGFβ. Nonetheless, targeting the activation of TGFβ signaling with maximized specificity and minimized toxicity can enhance the efficacy of therapeutic approaches against this signaling pathway. The molecules that are used to target TGFβ are non-cytotoxic to cancer cells but designed to curtail the over-activation of invasion and metastasis driving TGFβ signaling in stromal and cancer cells. Here, we discussed the critical role of TGFβ in tumorigenesis, and metastasis, as well as the outcome and the promising achievement of TGFβ inhibitory molecules in the treatment of cancer.

Targeting transforming growth factor-β signaling for enhanced cancer chemotherapy

During the past decades, drugs targeting transforming growth factor-β (TGFβ) signaling have received tremendous attention for late-stage cancer treatment since TGFβ signaling has been recognized as a prime driver for tumor progression and metastasis. Nonetheless, in healthy and pre-malignant tissues, TGFβ functions as a potent tumor suppressor. Furthermore, TGFβ signaling plays a key role in normal development and homeostasis by regulating cell proliferation, differentiation, migration, apoptosis, and immune evasion, and by suppressing tumor-associated inflammation. Therefore, targeting TGFβ signaling for cancer therapy is challenging. Recently, we and others showed that blocking TGFβ signaling increased chemotherapy efficacy, particularly for nanomedicines. In this review, we briefly introduce the TGFβ signaling pathway, and the multifaceted functions of TGFβ signaling in cancer, including regulating the tumor microenvironment (TME) and the behavior of cancer cells. We also summarize TGFβ targeting agents. Then, we highlight TGFβ inhibition strategies to restore the extracellular matrix (ECM), regulate the tumor vasculature, reverse epithelial-mesenchymal transition (EMT), and impair the stemness of cancer stem-like cells (CSCs) to enhance cancer chemotherapy efficacy. Finally, the current challenges and future opportunities in targeting TGFβ signaling for cancer therapy are discussed.

Betaglycan Gene (TGFBR3) Polymorphism Is Associated with Increased Risk of Endometrial Cancer

We investigated single nucleotide polymorphism (SNP) of the betaglycan gene (TGFBR3) encoding the TGFβ co-receptor in endometrial cancer (EC) and its association with betaglycan expression. The study group included 153 women diagnosed with EC and 248 cancer-free controls. SNP genotyping and gene expression were analyzed using TaqMan probes. Three out of the eight SNPs tested, i.e., rs12566180 (CT; OR = 2.22; 95% CI = 1.15-4.30; p = 0.0177), rs6680463 (GC; OR = 2.34; 95% CI = 1.20-4.53; p = 0.0120) and rs2296621 (TT; OR = 6.40; 95% CI = 1.18-34.84; p = 0.0317) were found to be significantly associated with increased risk of EC (adjusted to age, body mass index, menarche and parity). Among the analyzed SNPs, only rs2296621 demonstrated the impact on the increased cancer aggressiveness evaluated by the WHO grading system (G3 vs. G1/2, GT-OR = 4.04; 95% CI = 1.56-10.51; p = 0.0026; T-OR = 2.38; 95% CI = 1.16-4.85; p = 0.0151). Linkage disequilibrium (LD) analysis revealed high LD (r2 ≥ 0.8) in two haploblocks, constructed by rs2770186/rs12141128 and rs12566180/rs6680463, respectively. In the case of C/C haplotype (OR = 4.82; 95% CI = 1.54-15.07; p = 0.0116-Bonferroni corrected) and T/G haplotype (OR = 3.25; 95% CI = 1.29-8.15; p = 0.0328-Bonferroni corrected) in haploblock rs12566180/rs6680463, significantly higher frequency was observed in patients with EC as compared to the control group. The genotype-phenotype studies showed that SNPs of the TGFBR3 gene associated with an increased risk of EC, i.e., rs12566180 and rs2296621 may affect betaglycan expression at the transcriptomic level (rs12566180-CC vs. TT, p < 0.01; rs2296621-GG vs. TT, p < 0.001, GT vs. TT, p < 0.05). Functional consequences of evaluated TGFBR3 gene SNPs were supported by RegulomeDB search. In conclusion, polymorphism of the TGFBR3 gene may be associated with an increased EC occurrence, as well as may be the molecular mechanism responsible for observed betaglycan down-regulation in EC patients.

Construction and analysis of a competing endogenous RNA network to reveal potential prognostic biomarkers for Oral Floor Squamous Cell Carcinoma

Background

Patients diagnosed with Oral Floor Squamous Cell Carcinoma (OFSCC) face considerable challenges in physiology and psychology. This study explored prognostic signatures to predict prognosis in OFSCC through a detailed transcriptomic analysis.

Method

We built an interactive competing endogenous RNA (ceRNA) network that included lncRNAs, miRNAs and mRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to predict the gene functions and regulatory pathways of mRNAs. Least absolute shrinkage and selection operator algorithm (LASSO) analysis and Cox regression analysis were used to screen prognosis factors. The Kaplan-Meier method was used to analyze the survival rate of prognosis factors. Risk score was used to assess the reliability of the prediction model.

Results

A specific ceRNA network consisting of 56 mRNAs, 16 miRNAs and 31 lncRNAs was established. Three key genes (HOXC13, TGFBR3, KLHL40) and 4 clinical factors (age, gender, TNM, and clinical stage) were identified and effectively predicted the for survival time. The expression of a gene signature was validated in two external validation cohorts. The signature (areas under the curve of 3 and 5 years were 0.977 and 0.982, respectively) showed high prognostic accuracy in the complete TCGA cohort.

Conclusions

Our study successfully developed an extensive ceRNA network for OFSCC and further identified a 3-mRNA and 4-clinical-factor signature, which may serve as a biomarker.

The tumour microenvironment and metabolism in renal cell carcinoma targeted or immune therapy

Renal cell carcinoma (RCC) is one of the most common tumours of the urinary system, and is insidious and not susceptible to chemoradiotherapy. As the most common subtype of RCC (70-80% of cases), clear cell renal cell carcinoma (ccRCC) is characterized by the loss of von Hippel-Lindau and the accumulation of robust lipid and glycogen. For advanced RCC, molecular-targeted drugs, tyrosine kinase inhibitors (TKIs) and the immune checkpoint inhibitors (ICIs) have been increasingly recommended and investigated. Due to the existence of a highly dynamic, adaptive and heterogeneous tumour microenvironment (TME), and due to the glucose and lipid metabolism in RCC, this cancer may be accompanied by various types of resistance to TKIs and ICIs. With the increased production of lactate, nitric oxide, and other new by-products of metabolism, novel findings of the TME and key metabolic enzymes drived by HIF and other factors have been increasingly clarified in RCC carcinogenesis and therapy. However, there are few summaries of the TME and tumour metabolism for RCC progression and therapy. Here, we summarize and discuss the relationship of the important implicated characteristics of the TME as well as metabolic molecules and RCC carcinogenesis to provide prospects for future treatment strategies to overcome TME-related resistance in RCC.

Therapeutic Targets for the Treatment of Cardiac Fibrosis and Cancer: Focusing on TGF-β Signaling

Transforming growth factor-β (TGF-β) is a common mediator of cancer progression and fibrosis. Fibrosis can be a significant pathology in multiple organs, including the heart. In this review, we explain how inhibitors of TGF-β signaling can work as antifibrotic therapy. After cardiac injury, profibrotic mediators such as TGF-β, angiotensin II, and endothelin-1 simultaneously activate cardiac fibroblasts, resulting in fibroblast proliferation and migration, deposition of extracellular matrix proteins, and myofibroblast differentiation, which ultimately lead to the development of cardiac fibrosis. The consequences of fibrosis include a wide range of cardiac disorders, including contractile dysfunction, distortion of the cardiac structure, cardiac remodeling, and heart failure. Among various molecular contributors, TGF-β and its signaling pathways which play a major role in carcinogenesis are considered master fibrotic mediators. In fact, recently the inhibition of TGF-β signaling pathways using small molecule inhibitors, antibodies, and gene deletion has shown that the progression of several cancer types was suppressed. Therefore, inhibitors of TGF-β signaling are promising targets for the treatment of tissue fibrosis and cancers. In this review, we discuss the molecular mechanisms of TGF-β in the pathogenesis of cardiac fibrosis and cancer. We will review recent in vitro and in vivo evidence regarding antifibrotic and anticancer actions of TGF-β inhibitors. In addition, we also present available clinical data on therapy based on inhibiting TGF-β signaling for the treatment of cancers and cardiac fibrosis.

TGF-β and microRNA Interplay in Genitourinary Cancers

Genitourinary cancers (GCs) include a large group of different types of tumors localizing to the kidney, bladder, prostate, testis, and penis. Despite highly divergent molecular patterns, most GCs share commonly disturbed signaling pathways that involve the activity of TGF-β (transforming growth factor beta). TGF-β is a pleiotropic cytokine that regulates key cancer-related molecular and cellular processes, including proliferation, migration, invasion, apoptosis, and chemoresistance. The understanding of the mechanisms of TGF-β actions in cancer is hindered by the "TGF-β paradox" in which early stages of cancerogenic process are suppressed by TGF-β while advanced stages are stimulated by its activity. A growing body of evidence suggests that these paradoxical TGF-β actions could result from the interplay with microRNAs: Short, non-coding RNAs that regulate gene expression by binding to target transcripts and inducing mRNA degradation or inhibition of translation. Here, we discuss the current knowledge of TGF-β signaling in GCs. Importantly, TGF-β signaling and microRNA-mediated regulation of gene expression often act in complicated feedback circuits that involve other crucial regulators of cancer progression (e.g., androgen receptor). Furthermore, recently published in vitro and in vivo studies clearly indicate that the interplay between microRNAs and the TGF-β signaling pathway offers new potential treatment options for GC patients.

SILAC-Based Quantification of TGFBR2-Regulated Protein Expression in Extracellular Vesicles of Microsatellite Unstable Colorectal Cancers

Microsatellite unstable (MSI) colorectal cancers (CRCs) are characterized by mutational inactivation of Transforming Growth Factor Beta Receptor Type 2 (TGFBR2). TGFBR2-deficient CRCs present altered target gene and protein expression. Such cellular alterations modulate the content of CRC-derived extracellular vesicles (EVs). EVs function as couriers of proteins, nucleic acids, and lipids in intercellular communication. At a qualitative level, we have previously shown that TGFBR2 deficiency causes overall alterations in the EV protein content. To deepen the basic understanding of altered protein dynamics, this work aimed to determine TGFBR2-dependent EV protein signatures in a quantitative manner. Using a stable isotope labeling with amino acids in cell culture (SILAC) approach for mass spectrometry-based quantification, 48 TGFBR2-regulated proteins were identified in MSI CRC-derived EVs. Overall, TGFBR2 deficiency caused upregulation of several EV proteins related to the extracellular matrix and nucleosome as well as downregulation of proteasome-associated proteins. The present study emphasizes the general overlap of proteins between EVs and their parental CRC cells but also highlights the impact of TGFBR2 deficiency on EV protein composition. From a clinical perspective, TGFBR2-regulated quantitative differences of protein expression in EVs might nominate novel biomarkers for liquid biopsy-based MSI typing in the future.

Transforming growth factor β signaling pathway: A promising therapeutic target for cancer

Transforming growth factor β (TGF-β) is part of the transforming growth factor β superfamily which is involved in many physiological processes and closely related to the carcinogenesis. Here, we discuss the TGF-β structure, function, and its canonical Smads signaling pathway. Importantly, TGF-β has been proved that it plays both tumor suppressor as well as an activator role in tumor progression. In an early stage, TGF-β inhibits cell proliferation and is involved in cell apoptosis. In an advanced tumor, TGF-β signaling pathway induces tumor invasion and metastasis through promoting angiogenesis, epithelial-mesenchymal transition, and immune escape. Furthermore, we are centered on updated research results into the inhibitors as drugs which have been studied in preclinical or clinical trials in tumor carcinogenesis to prevent the TGF-β synthesis and block its signaling pathways such as antibodies, antisense molecules, and small-molecule tyrosine kinase inhibitors. Thus, it is highlighting the crucial role of TGF-β in tumor therapy and may provide opportunities for the new antitumor strategies in patients with cancer.

Integrin Subunit beta 8 (ITGB8) Upregulation Is an Independent Predictor of Unfavorable Survival of High-Grade Serous Ovarian Carcinoma Patients

Background

ITGB8 encodes a β subunit of integrin (integrin β8), which is upregulated in some types of cancer. In the current study, we examined the expression profile of ITGB8 in serous ovarian cancer (SOVC) and investigated its potential as an independent prognostic indicator for overall survival (OS) and recurrence-free survival (RFS) in high-grade SOVC.

Material/Methods

A secondary study was conducted based on genomic and survival data in large online databases, including the Gene Expression Omnibus (GEO), the Human Protein Atlas (HPA), and the Cancer Genome Atlas-Ovarian cancer (TCGA-OV). Kaplan-Meier curves were generated to evaluate the association between ITGB8 expression and OS/RFS. Univariate and multivariate analysis were performed with the Cox regression model.

Results

ITGB8 was significantly upregulated in ovarian cancer tissues compared to that in normal ovary tissues. High-grade SOVC patients with high ITGB8 expression had significantly shorter OS and RFS compared to their low-expression counterparts. Increased ITGB8 expression might be an independent prognostic indicator of unfavorable OS (HR: 1.424, 95%CI: 1.228–1.653, p<0.001) and RFS (HR: 2.167, 95%CI: 1.507–3.114, p<0.001) in high-grade SOVC. DNA amplification was frequent (149/509, 29.3%) in high-grade SOVC patients and was associated with increased ITGB8 expression compared to the copy-neutral cases.

Conclusions

ITGB8 expression might be a valuable prognostic biomarker in high-grade SOVC, the expression of which might be regulated by its DNA copy numbers.

TGF-β receptors: In and beyond TGF-β signaling

Transforming growth factor β (TGF-β) plays an important role in normal development and homeostasis. Dysregulation of TGF-β responsiveness and its downstream signaling pathways contribute to many diseases, including cancer initiation, progression, and metastasis. TGF-β ligands bind to three isoforms of the TGF-β receptor (TGFBR) with different affinities. TGFBR1 and 2 are both serine/threonine and tyrosine kinases, but TGFBR3 does not have any kinase activity. They are necessary for activating canonical or noncanonical signaling pathways, as well as for regulating the activation of other signaling pathways. Another prominent feature of TGF-β signaling is its context-dependent effects, temporally and spatially. The diverse effects and context dependency are either achieved by fine-tuning the downstream components or by regulating the expressions and activities of the ligands or receptors. Focusing on the receptors in events in and beyond TGF-β signaling, we review the membrane trafficking of TGFBRs, the kinase activity of TGFBR1 and 2, the direct interactions between TGFBR2 and other receptors, and the novel roles of TGFBR3.

Meta-analysis of gene expression and integrin-associated signaling pathways in papillary renal cell carcinoma subtypes

Papillary renal cell carcinoma (PRCC) is the second most common renal cell carcinoma (RCC) that can be further subdivided into type 1 (PRCC1) and type 2 (PRCC2) RCCs based on histological and genetic features. PRCC2 is often more aggressive than PRCC1. While integrin-associated protein complexes mediate tumorigenesis and metastases in many types of cancers it is not known whether integrin-mediated signaling impacts PRCC and differs between PRCC1 and PRCC2. In this study, we combined the analysis of five PRCC gene expression datasets derived from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) by using integrative bioinformatics pipelines. We found 1475 differentially expressed genes among which 37 genes were associated with integrin pathways. In comparison with PRCC1, PRCC2 cases showed upregulated expression of α5-integrin (ITGA5) whereas the expression of α6- (ITGA6) and β8-integrins (ITGB8) was downregulated. Because PRCC2 occurs more frequently in men, the meta-analysis was extended to explore the gender effects. This analysis revealed 8 genes but none of them was related to integrin pathways suggesting that other mechanisms than integrin-mediated signaling underlie the observed gender differences in the pathogenicity of PRCC2.

Decreased TGFBR3/betaglycan expression enhances the metastatic abilities of renal cell carcinoma cells through TGF-β-dependent and -independent mechanisms

TGF-β regulates both the tumor-forming and migratory abilities of various types of cancer cells. However, it is unclear how the loss of TGF-β signaling components affects these abilities in clear-cell renal cell carcinoma (ccRCC). In this study, we investigated the role of TGFBR3 (TGF-β type III receptor, also known as betaglycan) in ccRCC. Database analysis revealed decreased expression of TGFBR3 in ccRCC tissues, which correlated with poor prognosis in patients. Orthotopic inoculation experiments using immunocompromised mice indicated that low TGFBR3 expression in ccRCC cells enhanced primary tumor formation and lung metastasis. In the presence of TGFBR3, TGF-β2 decreased the aldehyde dehydrogenase (ALDH)-positive ccRCC cell population, in which renal cancer-initiating cells are enriched. Loss of TGFBR3 also enhanced cell migration in cell culture and induced expression of several mesenchymal markers in a TGF-β-independent manner. Increased lamellipodium formation by FAK-PI3K signaling was observed with TGFBR3 downregulation, and this contributed to TGF-β-independent cell migration in ccRCC cells. Taken together, our findings reveal that loss of TGFBR3 endows ccRCC cells with multiple metastatic abilities through TGF-β-dependent and independent pathways.

Heparan Sulfate and Heparan Sulfate Proteoglycans in Cancer Initiation and Progression

Heparan sulfate (HS) are complex unbranched carbohydrate chains that are heavily modified by sulfate and exist either conjugated to proteins or as free, unconjugated chains. Proteins with covalently bound Heparan sulfate chains are termed Heparan Sulfate Proteoglycans (HSPGs). Both HS and HSPGs bind to various growth factors and act as co-receptors for different cell surface receptors. They also modulate the dynamics and kinetics of various ligand-receptor interactions, which in turn can influence the duration and potency of the signaling. HS and HSPGs have also been shown to exert a structural role as a component of the extracellular matrix, thereby altering processes such as cell adhesion, immune cell infiltration and angiogenesis. Previous studies have shown that HS are deregulated in a variety of solid tumors and hematological malignancies and regulate key aspects of cancer initiation and progression. HS deregulation in cancer can occur as a result of changes in the level of HSPGs or due to changes in the levels of HS biosynthesis and remodeling enzymes. Here, we describe the major cell-autonomous (proliferation, apoptosis/senescence and differentiation) and cell-non-autonomous (angiogenesis, immune evasion, and matrix remodeling) roles of HS and HSPGs in cancer. Finally, we discuss therapeutic opportunities for targeting deregulated HS biosynthesis and HSPGs as a strategy for cancer treatment.

Potential role of BCL2 in the recurrence of uterine smooth muscle tumors of uncertain malignant potential

Uterine smooth muscle tumors are the most common female genital tract neoplasms. While leiomyosarcoma has been studied at length, smooth muscle tumors of uncertain malignant potential (STUMPs) still have ambiguous and unresolved issues, with a risk of relapse and evolution largely undefined. We performed an array comparative genomic hybridization analysis on a primitive STUMP and its local recurrence, histologically diagnosed as undifferentiated sarcoma. To the best of our knowledge, our report is the first genomic study on primitive STUMPs and the different relapsed tumors. The results showed few copy number alterations shared between both samples and the high heterogeneity in the STUMP was apparently lost in the sarcoma. Surprisingly the STUMP presented an amplification of the BCL2 gene, not observed in the relapsed tumor. Additionally, fluorescence in situ hybridization and immunohistochemical staining were performed to confirm BCL2 amplification and expression in these samples and in two other cases of primitive STUMPs and their corresponding relapsed tumors. The presence of BCL2 in multiple copies and expression in the two primitive STUMPs and two relapsed tumors was confirmed. The marked amplification of the BCL2 gene present in the primitive STUMP and the multiple copies also observed in other cases, suggest its potential role as a marker of STUMP malignant potential and recurrence.

Axl is required for TGF-β2-induced dormancy of prostate cancer cells in the bone marrow

Disseminated prostate cancer (PCa) cells in the marrow survive for years without evidence of proliferation, while maintaining the capacity to develop into metastatic lesions. These dormant disseminated tumor cells (DTCs) may reside in close proximity to osteoblasts, while expressing high levels of Axl, one of the tyrosine kinase receptors for growth arrest specific 6 (Gas6). Yet how Axl regulates DTC proliferation in marrow remains undefined. Here, we explored the impact of the loss of Axl in PCa cells (PC3 and DU145) on the induction of their dormancy when they are co-cultured with a pre-osteoblastic cell line, MC3T3-E1. MC3T3-E1 cells dramatically decrease the proliferation of PCa cells, however this suppressive effect of osteoblasts is significantly reduced by the reduction of Axl expression in PCa cells. Interestingly, expression of both TGF-β and its receptors were regulated by Axl expression in PCa cells, while specific blockade of TGF-β signaling limited the ability of the osteoblasts to induce dormancy of PCa cells. Finally, we found that both Gas6 and Axl are required for TGF-β2-mediated cell growth suppression. Taken together, these data suggest that a loop between the Gas6/Axl axis and TGF-β2 signaling plays a significant role in the induction of PCa cell dormancy.

TβRIII independently binds type I and type II TGF-β receptors to inhibit TGF-β signaling

Study of the TβRIII interaction with the signaling TGF-β receptors shows that TβRIII homo-oligomerization is indirect, depending largely on interactions with GIPC scaffolds. TβRI and II bind independently to TβRIII, competing with TβRI-TβRII complex formation and inhibiting Smad2/3 signaling by a mechanism independent of TβRIII ectodomain shedding.

Transforming growth factor-β (TGF-β) receptor oligomerization has important roles in signaling. Complex formation among type I and type II (TβRI and TβRII) TGF-β receptors is well characterized and is essential for signal transduction. However, studies on their interactions with the type III TGF-β coreceptor (TβRIII) in live cells and their effects on TGF-β signaling are lacking. Here we investigated the homomeric and heteromeric interactions of TβRIII with TβRI and TβRII in live cells by combining IgG-mediated patching/immobilization of a given TGF-β receptor with fluorescence recovery after photobleaching studies on the lateral diffusion of a coexpressed receptor. Our studies demonstrate that TβRIII homo-oligomerization is indirect and depends on its cytoplasmic domain interactions with scaffold proteins (mainly GIPC). We show that TβRII and TβRI bind independently to TβRIII, whereas TβRIII augments TβRI/TβRII association, suggesting that TβRI and TβRII bind to TβRIII simultaneously but not as a complex. TβRIII expression inhibited TGF-β–mediated Smad2/3 signaling in MDA-MB-231 cell lines, an effect that depended on the TβRIII cytoplasmic domain and did not require TβRIII ectodomain shedding. We propose that independent binding of TβRI and TβRII to TβRIII competes with TβRI/TβRII signaling complex formation, thus inhibiting TGF-β–mediated Smad signaling.

Transforming growth factor beta receptor type III is a tumor promoter in mesenchymal-stem like triple negative breast cancer

Introduction

There is a major need to better understand the molecular basis of triple negative breast cancer (TNBC) in order to develop effective therapeutic strategies. Using gene expression data from 587 TNBC patients we previously identified six subtypes of the disease, among which a mesenchymal-stem like (MSL) subtype. The MSL subtype has significantly higher expression of the transforming growth factor beta (TGF-β) pathway-associated genes relative to other subtypes, including the TGF-β receptor type III (TβRIII). We hypothesize that TβRIII is tumor promoter in mesenchymal-stem like TNBC cells.

Methods

Representative MSL cell lines SUM159, MDA-MB-231 and MDA-MB-157 were used to study the roles of TβRIII in the MSL subtype. We stably expressed short hairpin RNAs specific to TβRIII (TβRIII-KD). These cells were then used for xenograft tumor studies in vivo; and migration, invasion, proliferation and three dimensional culture studies in vitro. Furthermore, we utilized human gene expression datasets to examine TβRIII expression patterns across all TNBC subtypes.

Results

TβRIII was the most differentially expressed TGF-β signaling gene in the MSL subtype. Silencing TβRIII expression in MSL cell lines significantly decreased cell motility and invasion. In addition, when TβRIII-KD cells were grown in a three dimensional (3D) culture system or nude mice, there was a loss of invasive protrusions and a significant decrease in xenograft tumor growth, respectively. In pursuit of the mechanistic underpinnings for the observed TβRIII-dependent phenotypes, we discovered that integrin-α2 was expressed at higher level in MSL cells after TβRIII-KD. Stable knockdown of integrin-α2 in TβRIII-KD MSL cells rescued the ability of the MSL cells to migrate and invade at the same level as MSL control cells.

Conclusions

We have found that TβRIII is required for migration and invasion in vitro and xenograft growth in vivo. We also show that TβRIII-KD elevates expression of integrin-α2, which is required for the reduced migration and invasion, as determined by siRNA knockdown studies of both TβRIII and integrin-α2. Overall, our results indicate a potential mechanism in which TβRIII modulates integrin-α2 expression to effect MSL cell migration, invasion, and tumorigenicity.

Integrative identification of deregulated miRNA/TF-mediated gene regulatory loops and networks in prostate cancer

MicroRNAs (miRNAs) have attracted a great deal of attention in biology and medicine. It has been hypothesized that miRNAs interact with transcription factors (TFs) in a coordinated fashion to play key roles in regulating signaling and transcriptional pathways and in achieving robust gene regulation. Here, we propose a novel integrative computational method to infer certain types of deregulated miRNA-mediated regulatory circuits at the transcriptional, post-transcriptional and signaling levels. To reliably predict miRNA-target interactions from mRNA/miRNA expression data, our method collectively utilizes sequence-based miRNA-target predictions obtained from several algorithms, known information about mRNA and miRNA targets of TFs available in existing databases, certain molecular structures identified to be statistically over-represented in gene regulatory networks, available molecular subtyping information, and state-of-the-art statistical techniques to appropriately constrain the underlying analysis. In this way, the method exploits almost every aspect of extractable information in the expression data. We apply our procedure on mRNA/miRNA expression data from prostate tumor and normal samples and detect numerous known and novel miRNA-mediated deregulated loops and networks in prostate cancer. We also demonstrate instances of the results in a number of distinct biological settings, which are known to play crucial roles in prostate and other types of cancer. Our findings show that the proposed computational method can be used to effectively achieve notable insights into the poorly understood molecular mechanisms of miRNA-mediated interactions and dissect their functional roles in cancer in an effort to pave the way for miRNA-based therapeutics in clinical settings.

Role of TGF-β receptor III localization in polarity and breast cancer progression

The majority of breast cancers originate from the highly polarized luminal epithelial cells lining the breast ducts. However, cell polarity is often lost during breast cancer progression. The type III transforming growth factor-β cell surface receptor (TβRIII) functions as a suppressor of breast cancer progression and also regulates the process of epithelial-to-mesenchymal transition (EMT), a consequence of which is the loss of cell polarity. Many cell surface proteins exhibit polarized expression, being targeted specifically to the apical or basolateral domains. Here we demonstrate that TβRIII is basolaterally localized in polarized breast epithelial cells and that disruption of the basolateral targeting of TβRIII through a single amino acid mutation of proline 826 in the cytosolic domain results in global loss of cell polarity through enhanced EMT. In addition, the mistargeting of TβRIII results in enhanced proliferation, migration, and invasion in vitro and enhanced tumor formation and invasion in an in vivo mouse model of breast carcinoma. These results suggest that proper localization of TβRIII is critical for maintenance of epithelial cell polarity and phenotype and expand the mechanisms by which TβRIII prevents breast cancer initiation and progression.

Effects of TGF-β signaling in clear cell renal cell carcinoma cells

Clear cell renal cell carcinoma (ccRCC) is by far the most common type of kidney cancer and is characterized by loss of the tumor suppressor gene von Hippel-Lindau (VHL). ccRCC patients with metastatic disease has poor prognosis and today's therapy is insufficient. The cytokine Transforming Growth Factor-β (TGF-β) has been extensively studied in tumor biology and is believed to serve a variety of functions in tumor progression. We have previously shown that inhibition of NOTCH signaling causes a reduced migratory and invasive capacity of ccRCC cells, at least partly by a cross-talk with the TGF-β pathway. In the present study we aimed to further clarify the role of TGF-β signaling in ccRCC. We investigated the effects of TGF-β pathway modulation and showed that TGF-β inhibition attenuates the invasive capacity of ccRCC cells. By performing expression profiling we obtained a gene signature of the TGF-β induced response in ccRCC cells. The expression analyses revealed an extensive overlap between the TGF-β response and genes regulated by the hypoxia inducible factor (HIF). The link between the hypoxic and the TGF-β pathways was further corroborated by functional experiments, which demonstrated that TGF-β pathway activity was attenuated upon reintroduction of functional VHL in ccRCC.

Transient overexpression of TGFBR3 induces apoptosis in human nasopharyngeal carcinoma CNE-2Z cells

NPC (nasopharyngeal carcinoma) is a common malignancy in southern China without defined aetiology. Recent studies have shown that TGFBR3 (transforming growth factor type III receptor, also known as betaglycan), exhibits anticancer activities. This study was to investigate the effects of TGFBR3 on NPC growth and the mechanisms for its actions. Effects of TGFBR3 overexpression on cell viability and apoptosis were measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide], AO/EB (acridine orange/ethidium bromide) staining and electron microscopy in human NPC CNE-2Z cells. The expression of apoptosis-related proteins, p-Bad, Bad, XIAP (X-linked inhibitor of apoptosis), AIF (apoptosis-inducing factor), Bax and Bcl-2, was determined by Western blot or immunofluorescence analysis. Caspase 3 activity was measured by caspase 3 activity kit and [Ca²⁺]_i (intracellular Ca²⁺ concentration) was detected by confocal microscopy. Transfection of TGFBR3 containing plasmid DNA at concentrations of 0.5 and 1 μg/ml reduced viability and induced apoptosis in CNE-2Z in concentration- and time-dependent manners. Forced expression of TGFBR3 up-regulated pro-apoptotic Bad and Bax protein, and down-regulated anti-apoptotic p-Bad, Bcl-2 and XIAP protein. Furthermore, transient overexpression of TGFBR3 also enhanced caspase 3 activity, increased [Ca²⁺]_i and facilitated AIF redistribution from the mitochondria to the nucleus in CNE-2Z cells, which is independent of the caspase 3 pathway. These events were associated with TGFBR3-regulated multiple targets involved in CNE-2Z proliferation. Therefore transient overexpression of TGFBR3 may be a novel strategy for NPC prevention and therapy.

Convergent animal and human evidence suggests the activin/inhibin pathway to be involved in antidepressant response

Despite the overt need for improved treatment modalities in depression, efforts to develop conceptually novel antidepressants have been relatively unsuccessful so far. Here we present a translational approach combining results from hypothesis-free animal experiments with data from a genetic association study in depression. Comparing genes regulated by chronic paroxetine treatment in the mouse hippocampus with genes showing nominally significant association with antidepressant treatment response in two pharmacogenetic studies, the activin pathway was the only one to show this dual pattern of association and therefore selected as a candidate. We examined the regulation of activin A and activin receptor type IA mRNA following antidepressant treatment. We investigated the effects of stereotaxic infusion of activin into the hippocampus and the amygdala in a behavioural model of depression. To analyse whether variants in genes in the activin signalling pathway predict antidepressant treatment response, we performed a human genetic association study. Significant changes in the expression of genes in the activin signalling pathway were observed following 1 and 4 weeks of treatment. Injection of activin A into the hippocampus exerts acute antidepressant-like effects. Polymorphisms in the betaglycan gene, a co-receptor mediating functional antagonism of activin signalling, significantly predict treatment outcome in our system-wide pharmacogenetics study in depression. We provide convergent evidence from mouse and human data that genes in the activin signalling pathway are promising novel candidates involved in the neurobiogical mechanisms underlying antidepressant mechanisms of action. Further, our data suggest this pathway to be a target for more rapid-acting antidepressants in the future.

TGF-β - an excellent servant but a bad master

The transforming growth factor (TGF-β) family of growth factors controls an immense number of cellular responses and figures prominently in development and homeostasis of most human tissues. Work over the past decades has revealed significant insight into the TGF-β signal transduction network, such as activation of serine/threonine receptors through ligand binding, activation of SMAD proteins through phosphorylation, regulation of target genes expression in association with DNA-binding partners and regulation of SMAD activity and degradation. Disruption of the TGF-β pathway has been implicated in many human diseases, including solid and hematopoietic tumors. As a potent inhibitor of cell proliferation, TGF-β acts as a tumor suppressor; however in tumor cells, TGF-β looses anti-proliferative response and become an oncogenic factor. This article reviews current understanding of TGF-β signaling and different mechanisms that lead to its impairment in various solid tumors and hematological malignancies.

Reprint of: Betaglycan: a multifunctional accessory

Betaglycan is a co-receptor for the TGFβ superfamily, particularly important in establishing the potency of its ligands on their target cells. In recent years, new insights have been gained into the structure and function of betaglycan, expanding its role from that of a simple co-receptor to include additional ligand-dependent and ligand-independent roles. This review focuses on recent advances in the betaglycan field, with a particular emphasis on its newly discovered actions in mediating the trafficking of TGFβ superfamily receptors and as a determinant of the functional output of TGFβ superfamily signalling. In addition, this review encompasses a discussion of the emerging roles of the betaglycan/inhibin pathway in reproductive cancers and disease.

Microarray meta-analysis defines global angiogenesis-related gene expression signatures in human carcinomas

Angiogenesis is a prerequisite for progression of cancers. The number of genes linked to angiogenesis suggests the existence of complex gene-networks, which remain to be elucidated. To identify angiogenesis genes deregulated in carcinomas, we performed a meta-profiling analysis of published gene expression microarray studies. Own microarray and quantitative RT-PCR data were obtained from a colorectal carcinoma cohort. Applying highly stringent inclusion criteria, 15 cancer array studies were suitable for our analysis. These studies provided 789 tumor specimens and 190 samples of healthy tissues yielding a total of approx. 1,000,000 gene expression measurements. Meta-analysis on the expression of 480 angiogenesis-related genes in 10 cancer types identified a characteristic, entity-independent "global" cancer expression signature of 25 angiogenesis-related genes showing high frequency down-regulation when compared to corresponding healthy tissues. Furthermore, we characterized 25 genes displaying frequent up-regulation, yet less often than the 25 down-regulated genes. Comparative inter-study cross-validation revealed that both signatures discriminate cancers from healthy tissues with high accuracy in independent test sets. Moreover, own microarray data of colorectal carcinomas confirmed the specific and sensitive discriminating potential of both signatures. These results were validated by quantitative RT-PCR for eight genes displaying the highest differences in the microarray analysis. Our study for the first time defines global gene expression signatures linked to angiogenesis in carcinomas. Our findings suggest that gene down-regulation may represent a central aspect of tumor angiogenesis.

TGFBR3 polymorphisms and its haplotypes associated with chronic hepatitis B virus infection and age of hepatocellular carcinoma occurrence

OBJECTIVE

Hepatocellular carcinoma (HCC) is one of the most common cancers and is mainly caused by viral infections including hepatitis B virus (HBV). Recently, the decreased expression level of the transforming growth factor, beta receptor III (TGFBR3) gene, has been implicated in HCC and other human cancers. This study investigated whether TGFBR3 polymorphisms might be associated with HBV clearance and HCC occurrence.

METHODS

This study identified 27 single nucleotide polymorphisms (SNPs) in the exon, promoter, and exon-intron boundary regions of TGFBR3 by resequencing in 24 individuals. Then, 9 SNPs in the promoter and exons of the gene were genotyped from 1,065 Koreans composed of 637 chronic carriers (CC) and 428 spontaneously recovered (SR) subjects.

RESULTS

Two SNPs, rs1805113 (Phe676Phe) in exon 13 and rs1805117 in 3'-UTR (p = 0.009 and p = 0.008, respectively) were significantly associated with HBV clearance. In addition, Cox relative hazards analyses revealed that haplotype BL2_ht2 showed a significant association with the age of HCC occurrence among chronic HBV patients (relative hazard = 1.38; p = 0.007).

CONCLUSION

Our findings suggest that TGFBR3 polymorphisms and its haplotypes might be associated with HBV clearance and age of HCC occurrence.

The notch and TGF-β signaling pathways contribute to the aggressiveness of clear cell renal cell carcinoma

Background

Despite recent progress, therapy for metastatic clear cell renal cell carcinoma (CCRCC) is still inadequate. Dysregulated Notch signaling in CCRCC contributes to tumor growth, but the full spectrum of downstream processes regulated by Notch in this tumor form is unknown.

Methodology/Principal Findings

We show that inhibition of endogenous Notch signaling modulates TGF-β dependent gene regulation in CCRCC cells. Analysis of gene expression data representing 176 CCRCCs showed that elevated TGF-β pathway activity correlated significantly with shortened disease specific survival (log-rank test, p = 0.006) and patients with metastatic disease showed a significantly elevated TGF-β signaling activity (two-sided Student's t-test, p = 0.044). Inhibition of Notch signaling led to attenuation of both basal and TGF-β1 induced TGF-β signaling in CCRCC cells, including an extensive set of genes known to be involved in migration and invasion. Functional analyses revealed that Notch inhibition decreased the migratory and invasive capacity of CCRCC cells.

Conclusion

An extensive cross-talk between the Notch and TGF-β signaling cascades is present in CCRCC and the functional properties of these two pathways are associated with the aggressiveness of this disease.

Type III TGF-β receptor enhances colon cancer cell migration and anchorage-independent growth

The type III TGF-β receptor (TβRIII or betagylcan) is a TGF-β superfamily coreceptor with emerging roles in regulating TGF-β superfamily signaling and cancer progression. Alterations in TGF-β superfamily signaling are common in colon cancer; however, the role of TβRIII has not been examined. Although TβRIII expression is frequently lost at the message and protein level in human cancers and suppresses cancer progression in these contexts, here we demonstrate that, in colon cancer, TβRIII messenger RNA expression is not significantly altered and TβRIII expression is more frequently increased at the protein level, suggesting a distinct role for TβRIII in colon cancer. Increasing TβRIII expression in colon cancer model systems enhanced ligand-mediated phosphorylation of p38 and the Smad proteins, while switching TGF-β and BMP-2 from inhibitors to stimulators of colon cancer cell proliferation, inhibiting ligand-induced p21 and p27 expression. In addition, increasing TβRIII expression increased ligand-stimulated anchorage-independent growth, a resistance to ligand- and chemotherapy-induced apoptosis, cell migration and modestly increased tumorigenicity in vivo. In a reciprocal manner, silencing endogenous TβRIII expression decreased colon cancer cell migration. These data support a model whereby TβRIII mediates TGF-β superfamily ligand-induced colon cancer progression and support a context-dependent role for TβRIII in regulating cancer progression.

Betaglycan: a multifunctional accessory

Betaglycan is a co-receptor for the TGFβ superfamily, particularly important in establishing the potency of its ligands on their target cells. In recent years, new insights have been gained into the structure and function of betaglycan, expanding its role from that of a simple co-receptor to include additional ligand-dependent and ligand-independent roles. This review focuses on recent advances in the betaglycan field, with a particular emphasis on its newly discovered actions in mediating the trafficking of TGFβ superfamily receptors and as a determinant of the functional output of TGFβ superfamily signalling. In addition, this review encompasses a discussion of the emerging roles of the betaglycan/inhibin pathway in reproductive cancers and disease.

Reduction of transforming growth factor-beta type II receptor is caused by the enhanced ubiquitin-dependent degradation in human renal cell carcinoma

Although dysregulation of transforming growth factor-beta (TGF-beta) signaling is implicated in renal carcinogenesis, its precise mechanism is unknown in renal cell carcinoma (RCC). In our study, we investigated Smad-mediated TGF-beta signaling pathway and its regulatory mechanisms in surgical samples from patients with RCC. We found that immunoreactivity for nuclear phosphorylated Smad2 was significantly decreased in RCC compared to normal renal tissues, thereby TGF-beta signaling was suggested to be attenuated in RCC tissues. In accordance with the result, transcriptional downregulation of Smad4 and post-transcriptional downregulation of TGF-beta type II receptor (TbetaR-II) were frequently found in RCC tissues compared to normal renal tissues. Next, to clarify the reason why the protein level of TbetaR-II was decreased in RCC, we investigated the activities of degradation and ubiquitination of TbetaR-II. We found that both proteasome-mediated degradation and ubiquitination of TbetaR-II were markedly enhanced in RCC tissues. Moreover, we found that the level of Smad-ubiquitination regulatory factor 2 (Smurf2), the E3 ligase for TbetaR-II, was increased in RCC tissues of the patients with higher clinical stages compared to the normal tissues and was inversely correlated with the level of TbetaR-II. Our results suggest that the low TbetaR-II protein level is due to augmented ubiquitin-dependent degradation via Smurf2 and might be involved in the attenuation of TGF-beta signaling pathway in RCC.

[Defective expression of TGFBR3 gene and its molecular mechanisms in non-small cell lung cancer cell lines]

背景与目的

国外有研究表明，非小细胞肺癌（non-small cell lung cancer, NSCLC）中转化生长因子受体Ⅲ（TGFBR3）存在缺陷表达，但是分子机制尚未明确。本研究以正常支气管上皮细胞（human bronchial epithelial cell, HBEpiC）为对照，分析NSCLC细胞株中TGFBR3基因的表达情况，并探讨TGFBR3基因表达失活的分子机制。

方法

采用Western blot检测HBEpiC和NSCLC细胞株中TGFBR3的表达情况并做相对定量分析；采用DNA直接测序检测TGFBR3基因启动子基本转录元件区的突变情况；应用亚硫酸氢钠处理后测序法（bisulfite sequence-PCR, BSP）检测TGFBR3基因启动子区甲基化状态。

结果

NSCLC细胞株中TGFBR3表达水平明显低于HBEpiC；高转移细胞株95D明显低于非转移细胞株LTEP-α-2、A549、NCI-H460；HBEpiC与NSCLC细胞株中TGFBR3基因近端启动子区-165到-75区域无遗传突变，且未见甲基化，远端启动子区-314到-199区域均为高甲基化。

结论

TGFBR3基因在NSCLC细胞株中表达下调，在高转移细胞株95D中尤其明显，提示该基因的表达缺陷对NSCLC发生发展起重要作用，可能与NSCLC的侵袭和转移相关；然而，TGFBR3基因启动子区重要转录元件区域的甲基化状态并不是导致TGFBR3基因表达下调的主要原因。

Roles for the type III TGF-beta receptor in human cancer

Transforming growth factor beta (TGF-beta) superfamily ligands have important roles in regulating cellular homeostasis, embryonic development, differentiation, proliferation, immune surveillance, angiogenesis, motility, and apoptosis in a cell type and context specific manner. TGF-beta superfamily signaling pathways also have diverse roles in human cancer, functioning to either suppress or promote cancer progression. The TGF-beta superfamily co-receptor, the type III TGF-beta receptor (TbetaRIII, also known as betaglycan) mediates TGF-beta superfamily ligand dependent as well as ligand independent signaling to both Smad and non-Smad signaling pathways. Loss of TbetaRIII expression during cancer progression and direct effects of TbetaRIII on regulating cell migration, invasion, proliferation, and angiogenesis support a role for TbetaRIII as a suppressor of cancer progression and/or as a metastasis suppressor. Defining the physiological function and mechanism of TbetaRIII action and alterations in TbetaRIII function during cancer progression should enable more effective targeting of TbetaRIII and TbetaRIII mediated functions for the diagnosis and treatment of human cancer.

Loss of type III transforming growth factor-beta receptor expression is due to methylation silencing of the transcription factor GATA3 in renal cell carcinoma

Loss of transforming growth factor-beta receptor III (TbetaRIII) correlates with loss of transforming growth factor-beta (TGF-beta) responsiveness and suggests a role for dysregulated TGF-beta signaling in clear cell renal cell carcinoma (ccRCC) progression and metastasis. Here we identify that for all stages of ccRCC TbetaRIII expression is downregulated in patient-matched tissue samples and cell lines. We find that this loss of expression is not due to methylation of the gene and we define GATA3 as the first transcriptional factor to positively regulate TbetaRIII expression in human cells. We localize GATA3's binding to a 10-bp region of the TbetaRIII proximal promoter. We demonstrate that GATA3 mRNA is downregulated in all stages, of ccRCC, mechanistically show that GATA3 is methylated in ccRCC patient tumor tissues as well as cell lines, and that inhibiting GATA3 expression in normal renal epithelial cells downregulates TbetaRIII mRNA and protein expression. These data support a sequential model whereby loss of GATA3 expression through epigenetic silencing decreases TbetaRIII expression during ccRCC progression.

Loss of expression of TIMP3 in clear cell renal cell carcinoma

AIMS

In clear cell renal cell carcinoma (CCRCC), vascular endothelial growth factor (VEGF) represents the central positive mediator of tumour angiogenesis while VEGF receptor (VEGFR) is the primary target of anti-angiogenic therapies. TIMP3 is a physiological VEGFR-2 antagonist and thus could be considered as an anti-angiogenic factor. We therefore determined the status of this physiological inhibitor in CCRCC.

PATIENTS AND METHODS

Archival tumour from 105 patients was studied. TIMP3 expression was analysed using immuno-histochemistry and real-time RT-PCR. Results were correlated with clinicopathological variables. To analyse the mechanisms of gene silencing involved, we performed Multiplex Ligation-dependent Probe Amplification (MLPA) and methylation-specific MLPA (MS-MLPA). At last, we evaluated the main upstream pathway described implicating TGFbetaRII, which induces TIMP3 expression.

RESULTS

A down-expression of TIMP3, determined by immunohistochemistry, affected 100/105 renal cancers (95.2%). TIMP3 mRNA levels were significantly lower in high-grade tumours. Loss of heterozygosity of the TIMP3 gene was observed in 8 tumours (7.6%) and the 5'CpG island of the TIMP3 promoter was found to be methylated in 25 tumours (23.8%). A down-expression of TGFbetaRII was found in 85/105 CCRCCs (80.9%). A significant correlation was found between TIMP3 expression and TGFbetaRII expression.

CONCLUSIONS

This is the first demonstration that the loss of TIMP3 expression is observed in almost all CCRCCs. This loss of expression is a common molecular event in CCRCC. It may be an important initiation step for tumour development in a complex process implicating loss of heterozygosity on chromosome 22q, promoter hyper-methylation and inactivation of the TGFbetaRII pathway.

Late changes in cutaneous gene expression patterns after adjuvant treatment of oral squamous cell carcinoma (OSCC) by radiation therapy

OBJECTIVE

The objective of this study was to investigate radiation-induced late changes in cutaneous gene expression using a microarray platform and quantitative, real-time, reverse-transcriptase polymerase chain reaction (RT-PCR) validation.

STUDY DESIGN

Paired irradiated and nonirradiated skin biopsies were obtained from 19 patients with a history of oral squamous cell carcinoma (OSCC) treated by surgery and adjuvant radiotherapy at the time of secondary corrective surgery. Topic-defined PIQOR (Parallel Identification and Quantification of RNAs) skin microarrays were used to compare gene expression profiles between control and irradiated skin sample in 8 patients. The data were validated for matrixmetalloproteinase (MMP)-1 and tissue-inhibitor of matrixmetalloproteinase (TIMP)-1 by RT-PCR for all patients.

RESULTS

Irradiation markedly enhanced the expression of molecules associated with the transforming growth factor (TGF)-beta(1) signaling pathway, blood vessel development, as well as extracellular matrix constitution and turn-over.

CONCLUSIONS

Our data suggest that radiation-induced late changes in cutaneous gene expression mainly affect molecules related to extracellular matrix (ECM)-constitution and-remodeling.

Proteoglycan signaling co-receptors: roles in cell adhesion, migration and invasion

Signaling co-receptors are diverse, multifunctional components of most major signaling pathways, with roles in mediating and regulating signaling in both physiological and pathophysiological circumstances. Many of these signaling co-receptors, including CD44, glypicans, neuropilins, syndecans and TssRIII/betaglycan are also proteoglycans. Like other co-receptors, these proteoglycan signaling co-receptors can bind multiple ligands, promoting the formation of receptor signaling complexes and regulating signaling at the cell surface. The proteoglycan signaling co-receptors can also function as structural molecules to regulate adhesion, cell migration, morphogenesis and differentiation. Through a balance of these signaling and structural roles, proteoglycan signaling co-receptors can have either tumor promoting or tumor suppressing functions. Defining the role and mechanism of action of these proteoglycan signaling co-receptors should enable more effective targeting of these co-receptors and their respective pathways for the treatment of human disease.

The emerging role of TGF-beta superfamily coreceptors in cancer

The transforming growth factor beta (TGF-beta) signaling pathway plays a key role in different physiological processes such as development, cellular proliferation, extracellular matrix synthesis, angiogenesis or immune responses and its deregulation may result in tumor development. The TGF-beta coreceptors endoglin and betaglycan are emerging as modulators of the TGF-beta response with important roles in cancer. Endoglin is highly expressed in the tumor-associated vascular endothelium with prognostic significance in selected neoplasias and with potential to be a prime vascular target for antiangiogenic cancer therapy. On the other hand, the expression of endoglin and betaglycan in tumor cells themselves appears to play an important role in the progression of cancer, influencing cell proliferation, motility, invasiveness and tumorigenicity. In addition, experiments in vitro and in vivo in which endoglin or betaglycan expression is modulated have provided evidence that they act as tumor suppressors. The purpose of this review was to highlight the potential of membrane and soluble forms of the endoglin and betaglycan proteins as molecular targets in cancer diagnosis and therapy.

The type III TGF-beta receptor regulates epithelial and cancer cell migration through beta-arrestin2-mediated activation of Cdc42

Loss of expression of the TGF-beta superfamily coreceptor, the type III TGF-beta receptor (TbetaRIII or betaglycan), occurs in a broad spectrum of human cancers including breast, lung, ovarian, pancreatic, prostate, and renal cell cancer. TbetaRIII suppresses cancer progression in vivo, at least in part, by reducing cancer cell motility. However, the mechanism by which TbetaRIII regulates migration is unknown. Here, we demonstrate an unexpected TGF-beta signaling independent role for TbetaRIII in activating Cdc42, altering the actin cytoskeleton and reducing directional persistence to inhibit random migration of both cancer and normal epithelial cells. Functionally, TbetaRIII through its interaction with the scaffolding protein beta-arrestin2, activates Cdc42 and inhibits migration. These studies identify a TGF-beta independent homeostatic function for TbetaRIII in regulating cell migration.

The type III transforming growth factor-beta receptor negatively regulates nuclear factor kappa B signaling through its interaction with beta-arrestin2

Transforming growth factor-beta (TGF-beta) increases or decreases nuclear factor kappa B (NFkappaB) signaling in a context-dependent manner through mechanisms that remain to be defined. The type III transforming growth factor-beta receptor (TbetaRIII) is a TGF-beta superfamily co-receptor with emerging roles in both mediating and regulating TGF-beta superfamily signaling. We have previously reported a novel interaction of TbetaRIII with the scaffolding protein, beta-arrestin2, which results in TbetaRIII internalization and downregulation of TGF-beta signaling. beta-arrestin2 also scaffolds interacting receptors with the mitogen-activated protein kinase and NFkappaB-signaling pathways. Here, we demonstrate that TbetaRIII, through its interaction with beta-arrestin2, negatively regulates NFkappaB signaling in MCF10A breast epithelial and MDA-MB-231 breast cancer cells. Increasing TbetaRIII expression reduced NFkappaB-mediated transcriptional activation and IkappaBalpha degradation, whereas a TbetaRIII mutant unable to interact with beta-arrestin2, TbetaRIII-T841A, had no effect. In a reciprocal manner, short hairpin RNA-mediated silencing of either TbetaRIII expression or beta-arrestin2 expression increased NFkappaB-mediated transcriptional activation and IkappaBalpha degradation. Functionally, TbetaRIII-mediated repression of NFkappaB signaling is important for TbetaRIII-mediated inhibition of breast cancer cell migration. These studies define a mechanism through which TbetaRIII regulates NFkappaB signaling and expand the roles of this TGF-beta superfamily co-receptor in regulating epithelial cell homeostasis.