2-Methoxyestradiol exhibits the inhibitory activity of cellular proliferation in a breast carcinoma cell line MDA-MB-435 and an ovarian carcinoma cell line SK-OV-3 with IC50 of μM and μM, respectively. Furthermore, 2-Methoxyestradiol also inhibits cellular microtubule depolymerization in rat aortic smooth muscle A-10 cells with EC50 of μM.  2-Methoxyestradiol inhibits proliferation of MCF-7 and BM cells with IC50 of 52 μM and 8 μM.  In MDA-MB-231 cells, 2-Methoxyestradiol inhibits HIF-1-mediated transcriptional activation of target genes without affecting the transcription of HIF-1α itself.  A recent study shows that 2-Methoxyestradiol ( μM), blocks TGF-β3-induced expression of collagen (Col) type I(αI), Col III(αI), plasminogen activator inhibitor (PAI) 1, connective tissue growth factor (CTGF), and α-smooth muscle actin (α-SMA). Moreover, 2-Methoxyestradiol ameliorates TGF-β3-induced Smad2/3 phosphorylation and nuclear translocation, and inhibits TGF-β3-induced activation of the PI3K/Akt/mTOR pathway.