Interaction of the Tumor Metastasis Suppressor Nonmetastatic Protein 23 Homologue H1 and Estrogen Receptor α Alters Estrogen-Responsive Gene Expression

Abstract

Metastasis of cancer cells from the primary tumor is associated with poor prognosis and decreased overall survival. One protein implicated in inhibiting metastasis is the tumor metastasis suppressor nonmetastatic protein 23 homologue 1 (NM23-H1). NM23-H1 is a multifunctional protein, which, in addition to limiting metastasis, has DNase and histidine protein kinase activities. We have identified new functions for NM23-H1 in influencing estrogen receptor A (ERA)-mediated gene expression. Using a battery of molecular and biochemical techniques, we show that NM23-H1 interacts with ERA and increases the ERA-estrogen response element (ERE) interaction. When NM23-H1 expression is increased in U2 osteosarcoma and MDA-MB-231 breast cancer cells, transcription of a transiently transfected, estrogen-responsive reporter plasmid is decreased. More importantly, when endogenous NM23-H1 expression is knocked down in MCF-7 human breast cancer cells using small interfering RNA, estrogen responsiveness of the progesterone receptor (PR), Bcl-2, cathepsin D, and cyclin D1 genes, but not the pS2 gene, is enhanced. Furthermore, NM23-H1 associates with the region of the PR gene containing the +90 activator protein 1 site, but not with the ERE-containing region of the pS2 gene, indicating that NM23-H1 mediates gene-specific effects by association with endogenous chromatin. Our studies suggest that the capacity of NM23-H1 to limit the expression of estrogen-responsive genes such as cathepsin D and Bcl-2, which are involved in cell migration, apoptosis, and angiogenesis, may help to explain the metastasis-suppressive effects of this protein. The complementary abilities of ERA and NM23-H1 together to influence gene expression, cell migration, and apoptosis could be key factors in helping to determine tumor cell fate. [Cancer Res 2007;67(21):10600-7]

RETRACTED: Wnt-5a signaling restores tamoxifen sensitivity in estrogen receptor-negative breast cancer cells

“…CATD is constitutively expressed in MDA-MB-231 cells, and levels are not altered by the addition of estrogen. However, the expression of CATD is inhibited when cells are treated with tamoxifen (15,34). EBAG9 has been shown to be expressed at a very low level in MDA-MB-231 cells without the addition of estrogen, and robustly expressed after estrogen treatment in ER␣ positive MCF-7 cells (15).…”

Learning about the functions of NME/NM23: lessons from knockout mice to silencing strategies

“…The same group, also by using NME1 silencing, identified an interaction between NME1 and the macrophage migration inhibitory factor (MIF) that alleviates MIF-mediated suppression of p53 activity (Jung et al 2008). Experiments by Curtis et al (2007) using NME1 siRNA, have shown that NME1, which was reported to interact with the estrogen receptor α, could modulate estrogen responsiveness. Additional studies are needed to further generalize the physiological importance of NME1 and its specificity as compared to NME2, in regulating pathways as important as TGF-β and p53.…”

Janus-faces of NME–oncoprotein interactions

“…Oestrogen is an important mitogen but is also a potent regulator of cell motility and migration resulting from signalling via the oestrogen receptor (Gallo et al 2010), and thus, studies identifying interactions with NMEs immediately raise the question of whether the interactions might augment or modulate ER signalling. As with a number of NME PPIs, studies of oestrogen receptors have identified a high degree of selectivity of interaction with NME proteins: ER-α binds only to NME1 but not to NME2 as shown by co-immunoprecipitation and in vitro studies (Curtis et al 2007), whereas ER-β has only been shown to bind to NME2 (Rayner et al 2008). Curiously, whilst NME1 increases ER-α binding to oestrogen-responsive sequences as determined by gel mobility shift assays, it also promotes a reduction in activity from an oestrogen-responsive reporter construct.…”