Elsevier

Neoplasia

Volume 5, Issue 5, September–October 2003, Pages 417-426
Neoplasia

2-Methoxyestradiol Exhibits a Biphasic Effect on VEGF-A in Tumor Cells and Upregulation Is Mediated Through ER-α: A Possible Signaling Pathway Associated with the Impact of 2-ME2 on Proliferative Cells1

https://doi.org/10.1016/S1476-5586(03)80044-1Get rights and content
Under a Creative Commons license
open access

Abstract

2-Methoxyestradiol (2-ME2) was reported to elicit both stimulation and inhibition of tumor angiogenesis and growth depending on the dosage used. However, the mechanism(s) of the biphasic action of 2-ME2 has been elusive. Here we describe a regulatory role of vascular endothelial growth factor-A (VEGF-A) in the biphasic effects on estrogen receptor (ER)+ GH3 rat pituitary tumor cells and MCF-7 human breast tumor cells depending on the dosage of 2-ME2 used. We observed that acute exposure to 2-ME2, irrespective of dosage, did not alter cellular proliferation, but enhanced the VEGF-A mRNA level. As the treatment duration increased, biphasic effect was elicited. A concentration of 1 μM 2-ME2 increased both cell proliferation and VEGF-A levels in these cells, whereas higher doses exhibited reversed impact. A low dose of 2-ME2 also increased the VEGF-A mRNA expression in ER-α-transfected human mammary epithelial cells (HMECs). The effect was reversed in ER- cells. The enhanced expression of VEGF-A mRNA could be blocked by the pure estrogen antagonist, ICI 182,780, reveal that the upregulation of VEGF-A expression by 2-ME2 is mediated through ER-α. Furthermore, the biphasic effect of 2-ME2 on cell proliferation can be modulated by administrating VEGF-A antibodies or VEGF-A proteins. Studies also demonstrate that the VEGF-A protein, induced by 2-ME2, is functionally active and upregulates the proliferation of adjacent endothelial cells.

Keywords

2-methoxyestadiol
VEGF
ER-alpha
human mammary epithelial cells
transfection

Abbreviations

2-ME2
2-methoxyestradiol
BCEC
bovine capillary endothelial cell
CSPD
disodium 3-(4-methoxyspiro[1,2-dioxetane-3,2-(5-chloro)tricyclo[3.3.1.1,7]decan]-4-yl)phenyl phosphate
DIG
digoxigenin
ER
estrogen receptor
GAPDH
glyceraldehyde-3-phosphatedehydrogenase
HMEC
human mammary epithelial cell
MOPS
3-(N-morpholino)propanesulfonic acid
1 × PBS
1 × phosphate-buffered saline
PMSF
phenylmethylsulfonyl fluoride
VEGF-A
vascular endothelial growth factor-A
huMAb-VEGF-A
humanized monoclonal antibody directed against VEGF-A

Cited by (0)

1

This work is supported by NIH/NCI CA87680, V.A. merit review grant, the Midwest Biomedical Research Foundation grant, the EntreMed, Inc. research grant, the University of Kansas Medical Center departmental research grant.

2

Both authors have equal contributions to this work.

3

Present address: Zoology Department, Rammohan College, Kolkata, India.