4087

SMAD2

SMAD family member 2;SMAD2;SMAD family member 2

MAD homolog 2|SMAD, mothers against DPP homolog 2|Sma- and Mad-related protein 2|mother against DPP homolog 2|mothers against decapentaplegic homolog 2

18q21.1

protein-coding

The transforming growth factor beta (TGF-beta) signaling pathway has been considered both a tumor suppressor and a cancer promoter. Additionally, downregulation of cell adhesion molecules such as E-cadherin plays an important role in the metastatic potential of colorectal cancer (CRC). The aim of the present study was to evaluate TGF-beta, TGF-beta type I receptor (TGF-betaR1), TGF-beta type II receptor (TGF-betaR2), Smad4, pSmad2/3, and E-cadherin expression in colorectal carcinoma and to correlate the obtained data with other standard prognostic parameters, such as disease stage, metastases, and patient survival. TGF-beta, TGF-betaR1, TGF-betaR2, Smad4, pSmad2/3, and E-cadherin expression was evaluated immunohistochemically in 195 unrelated CRC specimens and the results subjected to various statistical analyses. TGF-beta was expressed in 71.28%, TGF-betaR1 in 61.0%, TGF-betaR2 in 54.4%, Smad4 in 61.5%, pSmad2/3 in 71.3%, and E-cadherin in 50.26% of the colorectal carcinoma samples tested. The correlation of immunoexpression with the clinicopathological parameters of CRC revealed that the high expression of TGF-beta and low expression of TGF-betaR1, TGF-betaR2, Smad4, pSmad2/3, and E-cadherin were correlated with tumor-node-metastasis (TNM) stage of disease. High TGF-beta expression and low TGF-betaR1, TGF-betaR2, Smad4, and pSmad2/3 expression were also correlated with lymph node metastasis. The Kaplan-Meier survival curves demonstrated a clear association of cancer-specific overall survival with high TGF-beta, as well as low TGF-betaR1, TGF-betaR2, Smad4, pSmad2/3, and E-cadherin expression. Our results suggest that TGF-beta, TGF-betaR1, TGF-betaR2, Smad4, pSmad2/3, and E-cadherin are closely related to TNM stage of CRC. Moreover, TGF-beta, TGF-betaR2, Smad4, pSmad2/3, and E-cadherin emerge as valuable independent biomarkers of prognosis in CRC patients.

Aberrant histone methylation is a frequent event during tumor development and progression. KMT1E (also known as SETDB1) is a histone H3K9 methyltransferase that contributes to epigenetic silencing of both oncogenes and tumor suppressor genes in cancer cells. In this report, we demonstrate that KMT1E acts as a metastasis suppressor that is strongly downregulated in highly metastatic lung cancer cells. Restoring KMT1E expression in this setting suppressed filopodia formation, migration, and invasive behavior. Conversely, loss of KMT1E in lung cancer cells with limited metastatic potential promoted migration in vitro and restored metastatic prowess in vivo. Mechanistic investigations indicated that KMT1E cooperates with the TGFbeta-regulated complex SMAD2/3 to repress metastasis through ANXA2. Together, our findings defined an essential role for the KMT1E/SMAD2/3 repressor complex in TGFbeta-mediated lung cancer metastasis.

BACKGROUND: Elevated TGF-beta levels are associated with prostate cancer progression. Although TGF-beta is a tumor suppressor for normal epithelial and early-stage cancer cells, it may act paradoxically as a tumor promoter in more advanced cancers, although its effects are largely cell and context dependent. This study analyzed prostate cancer responses to TGF-beta signaling in an isogenic model of androgen-sensitive and castration-resistant prostate cancer cells. METHODS: Phosphorylation and nuclear translocation of Smad2 and Smad3 were analyzed using immunoblotting. Proliferation and cell cycle responses to TGF-beta1 (5 ng/ml) were assessed using growth assays and flow cytometry for DNA content, as well as Western blot and immunoprecipitation of cell cycle proteins. RESULTS: Both androgen-sensitive (LNCaP) and castration-resistant (C4-2 and C4-2B) prostate cancer cell lines demonstrated TGF-beta1-induced phosphorylation and nuclear translocation of Smad2/3 that was robust in metastatic lines. Smad phosphorylation was completely abrogated with inhibition of ALK-5 kinase activity using the kinase inhibitor, SB-431542. Increased sensitivity to TGF-beta1-mediated growth inhibition was observed in C4-2 and C4-2B cells, as compared to LNCaP cells. This was paralleled with downregulation of Cyclin D and increased association of p15(Ink4b) or p27(Kip) with CDK's. Additionally, TGF-beta1 inhibited motility and invasion of metastatic cell lines. CONCLUSIONS: TGF-beta-mediated suppression of growth and motility is enhanced in metastatic, castration-resistant prostate cancer cells. Enhanced TGF-beta1-induced Smad2 and -3 signaling in prostate cancer cells may correlate with tumor suppressive activity. Therefore, the direct effects of TGF-beta1 on prostate cancer cells post-castration may be anti-tumorigenic and growth-suppressive.