Activation of Estrogen Receptor Alpha by Decitabine Inhibits Osteosarcoma Growth and Metastasis.

ABSTRACT: Osteosarcoma is a malignant tumor in the bone, which originates from normal osteoblasts or osteoblast precursors. Normal osteoblasts express estrogen receptor alpha (ER?); however, osteosarcomas do not express ER? due to promoter DNA methylation. Here we show that treatment of 143B osteosarcoma cells with decitabine (DAC, 5-Aza-2'-deoxycytidine) induces expression of ER? and leads to decreased proliferation and concurrent induction of osteoblast differentiation. DAC exposure reduced protein expression of metastasis-associated markers VIMENTIN, SLUG, ZEB1, and MMP9, with a concurrent decrease in mRNA expression of known stem cell markers SOX2, OCT4, and NANOG. Treatment with 17?-estradiol (E2) synergized with DAC to reduce proliferation. Overexpression of ER? inhibited proliferation and induced osteoblast differentiation, whereas knockout of ER? by CRISPR/Cas9 prevented the effects of DAC. In an orthotopic model of osteosarcoma, DAC inhibited tumor growth and metastasis of 143B cells injected into the tibia of NOD SCID gamma mice. Furthermore, ER? overexpression reduced tumor growth and metastasis, and ER? knockout prevented the effects of DAC in vivo. Together, these experiments provide preclinical evidence that the FDA-approved DNA methylation inhibitor DAC may be repurposed to treat patients with osteosarcoma based on its efficacy to decrease proliferation, to induce osteoblast differentiation, and to reduce metastasis to visceral organs.Significance: These findings describe the effects of DNA methyltransferase inhibition on ER? and its potential role as a tumor suppressor in osteosarcoma.See related commentary by Roberts, p. 1034 See related article by El Ayachi and colleagues; Cancer Res 79(5);982-93.

SUBMITTER: Lillo Osuna MA 

PROVIDER: S-EPMC6420872 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature