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The role of micro RNA ‐27a/b and micro RNA ‐494 in estrogen‐mediated downregulation of tissue factor pathway inhibitor α
Author(s) -
Ali H. O.,
Arroyo A. B.,
GonzálezConejero R.,
Stavik B.,
Iversen N.,
Sandset P. M.,
Martínez C.,
Skretting G.
Publication year - 2016
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.13321
Subject(s) - microrna , downregulation and upregulation , estrogen receptor , gene knockdown , transfection , cancer research , fulvestrant , tissue factor pathway inhibitor , estrogen receptor alpha , biology , microbiology and biotechnology , chemistry , tissue factor , cancer , cell culture , breast cancer , medicine , gene , biochemistry , genetics , coagulation
Essentials Estrogens are known to influence the expression of microRNAs in breast cancer cells. We looked at microRNAs in estrogenic regulation of tissue factor pathway inhibitor α (TFPIα). Estrogen upregulated microRNA‐27a/b and microRNA‐494 through the estrogen receptor α. MicroRNA‐27a/b and microRNA‐494 are partly involved in estrogenic downregulation of TFPIα.Summary Background Tissue factor pathway inhibitor ( TFPI ) has been linked to breast cancer pathogenesis. We have recently reported TFPI mRNA levels to be downregulated by estrogens in a breast cancer cell line ( MCF 7) through the estrogen receptor α ( ER α). Accumulating evidence also indicates that activation of ER α signaling by estrogens may modulate the expression of target genes indirectly through micro RNA s (mi RNA s). Objectives To examine if mi RNA s are involved in the estrogenic downregulation of TFPI α. Methods Computational analysis of the TFPI 3′‐untranslated region ( UTR ) identified potential binding sites for miR‐19a/b, miR‐27a/b, miR‐494, and miR‐24. Transient overexpression or inhibition of the respective mi RNA s was achieved by transfection of mi RNA mimics or inhibitors. Direct targeting of TFPI 3′‐ UTR by miR‐27a/b and miR‐494 was determined by luciferase reporter assay in HEK 293T cells. Effects of 17α‐ethinylestradiol ( EE 2) and fulvestrant on relative miR‐27a/b, miR‐494, and TFPI mRNA levels in MCF 7 cells were determined by qRT ‐ PCR and secreted TFPI α protein by ELISA . Transient knockdown of ER α was achieved by si RNA transfection. Results EE 2 treatment lead to a significant increase in miR‐19a, miR‐27a/b, miR‐494, and miR‐24 mRNA levels in MCF 7 cells through ER α. miR‐27a/b and miR‐494 mimics lead to reduced TFPI mRNA and protein levels. Luciferase assay showed direct targeting of miR‐27a/b and miR‐494 on TFPI mRNA . Impaired estrogen‐mediated downregulation of TFPI mRNA was detected in anti–miR‐27a/b and anti–miR‐494 transfected cells. Conclusions Our results provide evidence that miR‐27a/b and miR‐494 regulate TFPI α expression and suggest a possible role of these mi RNA s in the estrogen‐mediated downregulation of TFPI α.