Molecular and Cellular Biochemistry

, Volume 351, Issue 1, pp 157–164

Endothelial-specific intron-derived miR-126 is down-regulated in human breast cancer and targets both VEGFA and PIK3R2

Authors

  • Ni Zhu
    • Department of CardiologyChanghai Hospital
  • Dongze Zhang
    • Department of Physiology and Key lab of Ministry of Education in Fertility Preservation and MaintenanceNingxia Medical University
  • Haoping Xie
    • Department of Physiology and Key lab of Ministry of Education in Fertility Preservation and MaintenanceNingxia Medical University
  • Zhe Zhou
    • Department of Physiology and Key lab of Ministry of Education in Fertility Preservation and MaintenanceNingxia Medical University
  • Huyan Chen
    • Department of Physiology and Key lab of Ministry of Education in Fertility Preservation and MaintenanceNingxia Medical University
  • Tiantian Hu
    • Department of Physiology and Key lab of Ministry of Education in Fertility Preservation and MaintenanceNingxia Medical University
  • Yuan Bai
    • Department of CardiologyChanghai Hospital
  • Yuan Shen
    • Department of Breast SurgeryChanghai Hospital
  • Wenjun Yuan
    • Department of Physiology and Key lab of Ministry of Education in Fertility Preservation and MaintenanceNingxia Medical University
    • Department of PhysiologySecond Military Medical University
    • Department of CardiologyChanghai Hospital
    • Department of CardiologyChanghai Hospital
Article

DOI: 10.1007/s11010-011-0723-7

Cite this article as:
Zhu, N., Zhang, D., Xie, H. et al. Mol Cell Biochem (2011) 351: 157. doi:10.1007/s11010-011-0723-7

Abstract

Endothelial cells are the key components of vascular intima and play pivotal roles in vasculogenesis, angiogenesis, and tumor growth. Using Northern blot and real-time PCR, we confirmed that miR-126 and its host gene EGF-like domain 7 (EGFL7) were widely expressed in rat tissues but strictly expressed in endothelial cells. In mammals, miR-126 gene is embedded in intron7 of EGFL7. To explore the biogenesis of miR-126, plasmid EGFL7(126)-pEGFPc1 containing segment of exon7-intron7-exon8 of EGFL7 was constructed and expressed in 293T. Expression of spliced exon7–8 and excised mature miR-126 was detected by PCR and Northern blot. Knocking-down of endothelial endogenous miR-126 did not affect EGFL7 expression at mRNA or protein level. To investigate the possible roles of miR-126, PicTar, miRBase, miRanda, Bibiserv, and Targetscan were used to screen the targets. VEGFA and PIK3R2 were confirmed as the targets of miR-126 by luciferase reporter assay and Western blot. Interestingly, Northern blot and western blot showed that miR-126 was down-regulated in breast tumors where the VEGF/PI3K/AKT signaling pathway was activated. Introduction of miR-126 mimics into MCF-7 could effectively decrease VEGF/PI3K/AKT signaling activity. In summary, miR-126 was strictly expressed in endothelial cells and excised from EGFL7 pre-mRNA without affecting splicing and expression of its host gene. In addition, miR-126 could target both VEGFA and PIK3R2, and its expression was decreased in human breast cancer, implying that miR-126 may play a role in tumor genesis and growth by regulating the VEGF/PI3K/AKT signaling pathway.

Keywords

MicroRNAEGFL7VEGFAPIK3R2Endothelial cellBreast cancer

Supplementary material

11010_2011_723_MOESM1_ESM.ppt (343 kb)
Figure. S1 (A) The sequence of miR-126-3p and 5p are highly conserved in human, rat and mouse, fish and chicken. (B) Location of miR-126 in EGFL7 in human, mouse and rat. Figure. S2 Green fluorescence was observed in 293T which were transfected with pEGFPc1-EGFL7(126) (A) and pEGFPc1(B) after 24 h. (C) Luciferase activity was measured in 293T which were co-transfected of PGL3-VEGFA or PGL3-PIK3R2 with pEGFPc1-EGFL7(126) or pEGFPc1. Firefly luciferase was normalized to renilla luciferase. * P < 0.05 compares to controls. (PPT 343 kb)

Copyright information

© Springer Science+Business Media, LLC. 2011