β3 Integrin and Src facilitate transforming growth factor-β mediated induction of epithelial-mesenchymal transition in mammary epithelial cells

Introduction  

Transforming growth factor (TGF)-β suppresses breast cancer formation by preventing cell cycle progression in mammary epithelial cells (MECs). During the course of mammary tumorigenesis, genetic and epigenetic changes negate the cytostatic actions of TGF-β, thus enabling TGF-β to promote the acquisition and development of metastatic phenotypes. The molecular mechanisms underlying this conversion of TGF-β function remain poorly understood but may involve signaling inputs from integrins.     

Therapeutic targeting of the focal adhesion complex prevents oncogenic TGF-β signaling and metastasis

Introduction  

Mammary tumorigenesis is associated with the increased expression of several proteins in the focal adhesion complex, including focal adhesion kinase (FAK) and various integrins. Aberrant expression of these molecules occurs concomitant with the conversion of TGF-β function from a tumor suppressor to a tumor promoter. We previously showed that interaction between β₃ integrin and TβR-II facilitates TGF-β-mediated oncogenic signaling, epithelial-mesenchymal transition (EMT), and metastasis. However, the molecular mechanisms by which the focal adhesion complex contributes to β₃ integrin:TβR-II signaling and the oncogenic conversion of TGF-β remain poorly understood.     

XIAP gene expression and function is regulated by autocrine and paracrine TGF-β signaling

Background  

X-linked inhibitor of apoptosis protein (XIAP) is often overexpressed in cancer cells, where it plays a key role in survival and also promotes invasiveness. To date however, the extracellular signals and intracellular pathways regulating its expression and activity remain incompletely understood. We have previously showed that exposure to each of the three TGF-β (transforming growth factor beta) isoforms upregulates XIAP protein content in endometrial carcinoma cells in vitro. In the present study, we have investigated the clinical relevance of TGF-β isoforms in endometrial tumours and the mechanisms through which TGF-β isoforms regulate XIAP content in uterine cancer cells.     

Expression of thrombospondin-1 and Ski are prognostic factors in advanced gastric cancer

Background  

It has been suggested that thrombospondin-1 (TSP-1) plays a role in angiogenesis in many cancers. In addition, TSP-1 has been shown to suppress tumor growth by activating transforming growth factor-β (TGF-β). Recent studies have shown that Ski protein suppresses TGF-β signaling. The aim of this study was to investigate the role of TSP-1 and Ski expression in advanced gastric cancer.     

Expression of transforming growth factor-beta-1 and p27<Superscript>Kip1</Superscript> in pancreatic adenocarcinomas: relation with cell-cycle-associated proteins and clinicopathologic characteristics

Background  

The purpose of our study was to investigate the immunohistochemical expression of TGF-β1 and p27 in pancreatic adenocarcinomas and to compare the findings with the clinicopathological features and survival. We also aimed to evaluate the expression of TGF-β1 and p27 in the context of other cell cycle and proliferation markers such as cyclin D1 and Ki-67.     

Study on the expression and significance of TGF-��1, p-ERK1/2and K-ras in colorectal cancer using tissue microarray technique

Objective  

This study aimed to explore the expression and significance of transforming growth factor β1(TGF-β1), extracellular signal-regulated kinases 1/2 (ERK1/2), and K-ras in colorectal cancer (CRC) using tissue microarray technology.     

Identification of germline alterations of the mad homology 2 domain of SMAD3 and SMAD4 from the Ontario site of the breast cancer family registry (CFR)

Introduction  

A common feature of neoplastic cells is that mutations in SMADs can contribute to the loss of sensitivity to the anti-tumor effects of transforming growth factor-β (TGF-β). However, germline mutation analysis of SMAD3 and SMAD4, the principle substrates of the TGF-β signaling pathway, has not yet been conducted in breast cancer. Thus, it is currently unknown whether germline SMAD3 and SMAD4 mutations are involved in breast cancer predisposition.     

On the role of transforming growth factor-β in the growth inhibitory effects of retinoic acid in human pancreatic cancer cells

Background  

Retinoids are potent growth inhibitory and differentiating agents in a variety of cancer cell types. We have shown that retinoids induce growth arrest in all pancreatic cancer cell lines studied, regardless of their p53 and differentiation status. However, the mechanism of growth inhibition is not known. Since TGF-β2 is markedly induced by retinoids in other cancers and mediates MUC4 expression in pancreatic cancer cells, we investigated the role of TGF-β in retinoic acid-mediated growth inhibition in pancreatic cancer cells.     

Expression analysis of E-cadherin, Slug and GSK3β in invasive ductal carcinoma of breast

Background  

Cancer progression is linked to a partially dedifferentiated epithelial cell phenotype. The signaling pathways Wnt, Hedgehog, TGF-β and Notch have been implicated in experimental and developmental epithelial mesenchymal transition (EMT). Recent findings from our laboratory confirm that active Wnt/β-catenin signaling is critically involved in invasive ductal carcinomas (IDCs) of breast.     

SFRP1 reduction results in an increased sensitivity to TGF-β signaling

Background  

Transforming growth factor (TGF)-β plays a dual role during mammary gland development and tumorigenesis and has been shown to stimulate epithelial-mesenchymal transition (EMT) as well as cellular migration. The Wnt/β-catenin pathway is also implicated in EMT and inappropriate activation of the Wnt/β-catenin signaling pathway leads to the development of several human cancers, including breast cancer. Secreted frizzled-related protein 1 (SFRP1) antagonizes this pathway and loss of SFRP1 expression is frequently observed in breast tumors and breast cancer cell lines. We previously showed that when SFRP1 is knocked down in immortalized non-malignant mammary epithelial cells, the cells (TERT-siSFRP1) acquire characteristics associated with breast tumor initiating cells. The phenotypic and genotypic changes that occur in response to SFRP1 loss are consistent with EMT, including a substantial increase in the expression of ZEB2. Considering that ZEB2 has been shown to interact with mediators of TGF-β signaling, we sought to determine whether TGF-β signaling is altered in TERT-siSFRP1 cells.     

Expression and prognostic significance of THBS1, Cyr61 and CTGF in esophageal squamous cell carcinoma

Background  

Thrombospondin1 (THBS1), cystene-rich protein 61 (Cyr61) and connective tissue growth factor (CTGF) are all involved in the transforming growth factor-beta (TGF-β) signal pathway, which plays an important role in the tumorigenesis. The purpose of this study is to explore the expression and prognostic significance of these proteins in esophageal squamous cell carcinoma (ESCC).     

TGF-β may be complimentary to PSA in Chinese prostate cancer

Objective: To investigate the value of the plasma transforming growth factor β1 (TGF-β1) level in diagnosis and prognosis of prostate cancer (PCa). Methods: The ELISA kits for human TGF-β1 were used to measure the TGF-β1 level in plasmas. A cohort of 295 consecutive PCa patients in recent more than two years in the First Hospital of Peking University of China was enrolled to the study. Furthermore, 55 control subjects were healthy and without evidence of PCa, who were random people that came to the hospital and were identified by prostate biopsy. Results: An age-related frequency chart in dicated that 99% confidence interval of the difference with PCa was at the age of 53-85 years. The PCa patients aged 53-85 were classified into three groups according to TNM staging. Group A had Stages TO, T1 and T2. Group B had Stage T3 and Group C had Stage T4. Compared with control group, Group A had the lower level of plasma TGF-β1 (P ＜ 0.05), Group B had the higher level of plasma TGF-β1 (P ＜ 0.05) and Group C had the even higher level of plasma TGF-β1 (P ＜ 0.01). According to TNM staging, Group D had Stages T0, T1 and T2 with the normal level of total PSA (tPSA). Group E with the normal level of tPSA had metastasis after resection. Compared with control group, Group D had the lower plasma level of TGF-β1 (P ＜0.05)and Group E had higher plasma level of TGF-β1 (P ＜ 0.01). Conclusion: The plasma TGF-β1 level decreases at early stage of PCa and increases at later stage of PCa, especially at tumor metastasis after the resection. The plasma TGF-β1 level may therefore be complementary to PSA for PCa prognosis.     

Circulating transforming growth factor-β-1 and breast cancer prognosis: results from the Shanghai Breast Cancer Study

Introduction Studies investigating the prognostic effect of circulating TGF-β-1 in breast cancer have given inconsistent findings. The purpose of this study is to evaluate whether circulating transforming growth factor beta 1 (TGF-β-1) is associated with overall and disease-free survival in a cohort of recently diagnosed breast cancer patients. Methods We measured TGF-β-1 levels in plasma samples of breast cancer patients in the Shanghai Breast Cancer Study, a population-based case–control study. We evaluated the relationship between TGF-β-1 levels and overall and disease-free survival. The median follow up time was 7.2 years. Results We observed that, compared with the patients with the lowest quartile of plasma TGF-β-1, patients with the highest quartile of plasma TGF-β-1 had significantly worse overall survival with hazards ratio (HR) = 2.78, with 95% confidence interval (CI): 1.34–5.79 and disease-free survival with HR = 2.49, 95% CI: 1.15–5.41, while the patients with the second and third quartiles of plasma TGF-β-1 did not have significantly different overall and disease-free breast cancer survival. The shape of association between plasma TGF-β-1 levels and breast cancer survival appears to be non-linear. Stratified analysis by stage of disease did not appreciably change the association pattern. Conclusions We conclude that the relationship between circulating levels of TGF-β-1 and prognosis in breast cancer is complex and non-linear. High levels of TGF-β-1 are associated with worse survival independent of stage of disease.     

Targeting the oncogenic protein beta-catenin to enhance chemotherapy outcome against solid human cancers

Background  

Beta-catenin is a multifunctional oncogenic protein that contributes fundamentally to cell development and biology. Elevation in expression and activity of β-catenin has been implicated in many cancers and associated with poor prognosis. Beta-catenin is degraded in the cytoplasm by glycogen synthase kinase 3 beta (GSK-3β) through phosphorylation. Cell growth and proliferation is associated with β-catenin translocation from the cytoplasm into the nucleus.     

Antisense oligonucleotide targeting TGF-β1 abrogates tumorigenicity of rhabdomyosarcoma in vivo

Objective  Over-expression of transforming growth factor β1 (TGF-β1) has been observed in many advanced cancers. The present study was aimed at developing potential antisense oligonucleotides (ASONs) to repress TGF-β1 expression in rhabdomyosarcoma (RMS) RD cells, and to examine their effect on tumorigenicity of RD cells in vivo. Methods  ASONs targeting the region surrounding the start codon of TGF-β1 were synthesized and transferred into cells in the form of complexes with Lipofectamine 2000. The TGF-β1 protein was determined by immunofluorescence and ELISA. The cell viability and cell cycle were examined by MTT and flow cytometry. The RD cells, with or without TGF-β1ASON, in 50 μl of serum-free EMDM medium were injected subcutaneously into the right flank of nude mice. The tumors were then measured and weighed. Results  The ASON sequence targeting the first start site at bases 841–855 of the human TGF-β1 gene had the greatest effect on attenuating the expression of TGF-β1 (P < 0.05). The ASONs induced a decrease in OD values after 6 d (P < 0.05). Analysis of the cell cycle revealed that the ASON induced a significant decrease in cells in the S phase and an increase in cells in the G1 phase (P < 0.05). In the nude mice model, the mean tumor volume, after 2 weeks of treatment with Lipofectamine or ASON, decreased to 88.5% or 55% respectively, compared to the control tumor size, resulting in a significant difference (P < 0.01). Conclusion  The sequence of the ASON, which targeted the start condon at the bases 841–855 of the human TGF-β1 gene, was demonstrated to be a useful agent for studying the regulation of TGF-β1 over-expression in RD cells, and has important therapeutic potential for suppressing the tumorigenicity of human RMS in vivo. This work was supported by grants from the Jiangsu Provincial Higher Institution Natural Science Foundation (No.2134605) and the Jiangsu Provincial Post-Doctoral Foundation (No.51208).     

Analysis of transforming growth factor β receptor expression and signaling in higher grade meningiomas

TGF-β receptors (TGF-βRs) inhibit growth of many cell types. Loss of TGF-βRs or its signaling components have been found in several human malignancies. The expression and the role of TGF-βRs in regulating anaplastic meningioma growth has not been studied. Real time PCR found TGF-β RIII expression significantly lower in five grade III compared to eight grade I and eight grade II tumors (P = 0.0481). By western blot analysis, TGF-βRI was detected in the four fetal and adult leptomeninges, all 18 grade I, 14 grade II and six grade III meningiomas. TGF-βRII was detected in none of the leptomeninges, 55% of grade I, 71% of grade II and weak to negative in five of six the grade III meningiomas analyzed. TGF-βRIII immunoreactivity was not detected in the fetal meninges but was detected in 94% of grade I, 70% of grade II and 67% grade III tumors. Phospho-SMAD 3 and Smad 7 were detected in nearly all tumors. TGF-β1 had no effect on PDGF-BB stimulation of DNA synthesis in six of seven WHO grade II and the grade III cells. It produced an increase in phosphorylation of SMAD 3 and p38MAPK in two of four and p44/42MAPK in three of four grade II cells showing no change in DNA synthesis after treatment. Thus, only attenuated TGF-βRIII expression and TGFB growth inhibition may occur in select higher grade meningiomas. Nonetheless, restoring TGF-β inhibition of meningioma cell proliferation may be an important objective in the design of new chemotherapies for these tumors.