Fibulin-5 initiates epithelial-mesenchymal transition (EMT) and enhances EMT induced by TGF-beta in mammary epithelial cells via a MMP-dependent mechanism.

Department of Pharmacology, University of Colorado Health Sciences Center, Aurora, CO 80045, USA.
Carcinogenesis (Impact Factor: 5.27). 09/2008; 29(12):2243-51. DOI: 10.1093/carcin/bgn199
Source: PubMed

ABSTRACT Epithelial-mesenchymal transition (EMT) is a normal physiological process that regulates tissue development, remodeling and repair; however, aberrant EMT also elicits disease development in humans, including lung fibrosis, rheumatoid arthritis and cancer cell metastasis. Transforming growth factor-beta (TGF-beta) is a master regulator of EMT in normal mammary epithelial cells (MECs), wherein this pleiotropic cytokine also functions as a potent suppressor of mammary tumorigenesis. In contrast, malignant MECs typically evolve resistance to TGF-beta-mediated cytostasis and develop the ability to proliferate, invade and metastasize when stimulated by TGF-beta. It therefore stands to reason that establishing how TGF-beta promotes EMT may offer new insights into targeting the oncogenic activities of TGF-beta in human breast cancers. By monitoring alterations in the actin cytoskeleton and various markers of EMT, we show here that the TGF-beta gene target, fibulin-5 (FBLN5), initiates EMT and enhances that induced by TGF-beta. Whereas normal MECs contain few FBLN5 transcripts, those induced to undergo EMT by TGF-beta show significant upregulation of FBLN5 messenger RNA, suggesting that EMT and the dedifferentiation of MECs override the repression of FBLN5 expression in polarized MECs. We also show that FBLN5 stimulated matrix metalloproteinase expression and activity, leading to MEC invasion and EMT, to elevated Twist expression and to reduced E-cadherin expression. Finally, FBLN5 promoted anchorage-independent growth in normal and malignant MECs, as well as enhanced the growth of 4T1 tumors in mice. Taken together, these findings identify a novel EMT and tumor-promoting function for FBLN5 in developing and progressing breast cancers.

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    ABSTRACT: Dysregulation of BCL6 plays critical oncogenic roles and facilitates tumorigenesis in various malignancies. However, whether the aberrant expression of BCL6 in ovarian carcinoma is associated with malignancy, metastasis or prognosis remains unknown. Our study aimed to investigate the expression of BCL6 in ovarian carcinoma and its possible correlation with clinicopathological features as well as patient survival to reveal its biological effects in ovarian tumor progression. Immunochemistry analysis was performed in 105 cases of ovarian carcinoma covering the histological types of serous, endometrioid and clear cell. Spearman analysis was used to calculate the correlation between pathological parameters and the expression of BCL6. Kaplan-Meier method and Cox proportional hazards analysis were used to analyze the disease-specific survival (DSS) and disease-free survival (DFS). We also assessed whether overexpression and knockdown of BCL6 influence in vitro cell proliferation, cell cycle progression, as well as tumor cell invasion and migration. The expression of BCL6 was higher in all three major kinds of ovarian cancer in comparison with paratumorous epithelium. BCL6 expression was tightly correlated with FIGO staging, lymph node metastasis and recurrence. Higher expression of BCL6 led to a significantly poorer DSS and DFS and multivariate analysis revealed that BCL6 was an independent risk factor of DSS and DFS. Enforced overexpression of BCL6 in ovarian tumor cells stimulated proliferation by inducing G1-S transition, and promoted tumor cell invasion and migration. Conversely, RNA interference-mediated silencing BCL6 expression inhibited proliferation by altered cell cycle progression and reduced the ability of the cells to migrate, and invade the extracellular matrix in culture. Our study suggests that the inappropriate activation of BCL6 predicts poor prognosis and promotes tumor progression in ovarian carcinoma. Targeting BCL6 could be a novel therapeutic choice for treating ovarian carcinoma patients.
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    ABSTRACT: To explore the effect of Fibulin-5 expression on cell proliferation and invasion in human gastric cancer patients.
    Asian Pacific Journal of Tropical Medicine 10/2014; 7(10):787-791. DOI:10.1016/S1995-7645(14)60137-1 · 0.93 Impact Factor

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