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Promyelocytic leukemia protein (PML) regulates endothelial cell network formation and migration in response to tumor necrosis factor ? (TNF?) and interferon ? (IFN?).

ABSTRACT: Promyelocytic leukemia protein (PML) is a tumor suppressor that is highly expressed in vascular endothelium and inflamed tissues, yet its role in inflammation-associated cytokine-regulated angiogenesis and underlying mechanism remains largely unclear. We show that tumor necrosis factor ? (TNF?) and interferon ? (IFN?) stimulate PML expression while suppressing EC network formation and migration, two key events during angiogenesis. By a knockdown approach, we demonstrate that PML is indispensable for TNF?- and IFN?-mediated inhibition of EC network formation. We further demonstrate that signal transducer and activator of transcription 1 (STAT1) binds PML promoter and that is an important regulator of PML expression. Knockdown of STAT1 reduces endogenous PML and blocks TNF?- and IFN?-induced PML accumulation and relieves TNF?- and IFN?-mediated inhibition of EC network formation. Our data also indicate that PML regulates EC migration, in part, by modulating expression of downstream genes, such as negatively regulating integrin ?1 (ITGB1). In addition, knockdown of STAT1 or PML alleviates TNF?- and IFN?-mediated inhibition of ITGB1 expression. Antibody blockade demonstrates that ITGB1 is functionally important for PML- and STAT1-regulated EC migration. Taken together, our data provide novel mechanistic insights that PML functions as a negative regulator in EC network formation and migration.

SUBMITTER: Cheng X

PROVIDER: S-EPMC3390613 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

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Promyelocytic leukemia protein (PML) regulates endothelial cell network formation and migration in response to tumor necrosis factor α (TNFα) and interferon α (IFNα).

Cheng Xiwen X Liu Yu Y Chu Hao H Kao Hung-Ying HY

The Journal of biological chemistry 20120515 28

Promyelocytic leukemia protein (PML) is a tumor suppressor that is highly expressed in vascular endothelium and inflamed tissues, yet its role in inflammation-associated cytokine-regulated angiogenesis and underlying mechanism remains largely unclear. We show that tumor necrosis factor α (TNFα) and interferon α (IFNα) stimulate PML expression while suppressing EC network formation and migration, two key events during angiogenesis. By a knockdown approach, we demonstrate that PML is indispensable ...[more]

PMID: 22589541

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Project description:Dysregulation of PML, a significant tumor suppressor is linked with cancers of different histological origins, with a decreased expression observed with a higher tumor grade. This necessitates studying the mechanisms to maintain a stable expression of PML. However much less is known about the transcriptional regulation of PML, more so in the context of breast carcinoma. ERβ has emerged as a critical factor in understanding breast cancer, especially since a huge proportion of breast cancers are ERα- and thus insensitive to tamoxifen therapy. This study aims to uncover an unidentified mechanism of PML gene regulation and its stabilization in breast cancer via ERβ signalling and the impact on cellular apoptosis. We found that clinical expression of PML positively correlates with that of ERβ both in normal and breast carcinoma samples and inversely correlates with markers of cellular proliferation, hinting towards a possible mechanistic interdependence. Both mRNA and protein expression of PML were increased in response to ERβ overexpression on multiple human breast cancer cell lines. Mechanistically, luciferase reporter assays and chromatin-immunoprecipitation assays demonstrated that ERβ can interact with the PML promoter via ERE and AP1 sites to enhance its transcription. ERβ induced stable PML expression causes a decline of its target protein Survivin and simultaneously provides a stable docking platform leading to stabilisation of its target Foxo3a, further causing transcriptional upregulation of pro-apoptotic factors p21 and p27. Immunohistochemical analyses of cancer and normal breast tissues and functional assays conducted corroborated the findings. Collectively, our study identifies ERβ signalling as a novel mechanism for PML gene regulation in ERα- breast cancer. It also reveals bi-directional downstream effect in which 'ERβ-PML-(Foxo3a/Survivin)' network acts as a therapeutic axis by suppressing cellular survival and promoting cellular apoptosis in breast carcinoma.

Dataset Information

Promyelocytic leukemia protein (PML) regulates endothelial cell network formation and migration in response to tumor necrosis factor ? (TNF?) and interferon ? (IFN?).

Publications

Promyelocytic leukemia protein (PML) regulates endothelial cell network formation and migration in response to tumor necrosis factor α (TNFα) and interferon α (IFNα).

Similar Datasets

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