The G Protein-Coupled Estrogen Receptor-1, GPER-1, Promotes Fibrillogenesis via a Shc-Dependent Pathway Resulting in Anchorage-Independent Growth

Abstract

The G protein-coupled estrogen receptor-1, GPER-1, coordinates fibronectin (FN) matrix assembly and release of heparan-bound epidermal growth factor (HB-EGF). This mechanism of action results in the recruitment of FN-engaged integrin α5β1 to fibrillar adhesions and the formation of integrin α5β1-Shc adaptor protein complexes. Here, we show that GPER-1 stimulation of murine 4 T1 or human SKBR3 breast cancer cells with 17β-estradiol (E2β) promotes the formation of focal adhesions and actin stress fibers and results in increased cellular adhesion and haptotaxis on FN, but not collagen. These actions are also induced by the xenoestrogen, bisphenol A, and the estrogen receptor (ER) antagonist, ICI 182, 780, but not the inactive stereoisomer, 17α-estradiol (E2α). In addition, we show that GPER-1 stimulation of breast cancer cells allows for FN-dependent, anchorage-independent growth and FN fibril formation in “hanging drop” assays, indicating that these GPER-1-mediated actions occur independently of adhesion to solid substrata. Stable expression of Shc mutant Y317F lacking its primary tyrosyl phosphorylation site disrupts E2β-induced focal adhesion and actin stress fiber formation and abolishes E2β-enhanced haptotaxis on FN and anchorage-dependent growth. Collectively, these data demonstrate that E2β action via GPER-1 enhances cellular adhesivity and FN matrix assembly and allows for anchorage-independent growth, cellular events that may allow for cellular survival, and tumor progression.

The G protein‐coupled oestrogen receptor, GPER1, mediates direct anti‐inflammatory effects of oestrogens in human cholinergic neurones from the nucleus basalis of Meynert

“…Hence, the results obtained in the present study further suggest that GPER1 may mediate the effects of E 2 on neurite outgrowth in hfNBMs, as reported previously . Moreover, our findings appear to be in agreement with the demonstration that GPER1 stimulation with E 2 in different cellular systems (eg, breast cancer cells) promotes the formation of focal adhesions leading to the reorganisation of actin stress fibres and enhanced cellular adhesivity …”

Bisphenol A promotes the proliferation of leiomyoma cells by GPR30‐EGFR signaling pathway

“…E2 ligand binds to GPR30, making the G protein heterotrimeric disintegration into Gα and Gβγ. Gβγ can activate Src phosphorylation, thereby promote the cell membrane MMP, leading to HB‐EGF releasing and playing a role as a ligand to activate EGFR, therefore activation of its downstream signaling pathway, such as MAPK, ERK, PI3K, increased c‐fos and other transcriptional gene expression, thereby promoting cell proliferation and differentiation …”

The G-protein coupled estrogen receptor, GPER: The inside and inside-out story

“…thrombin and epinephrine) or chemokines interact with their respective GPCRs to regulate the affinity of platelet or leukocyte integrins to promote thrombus formation and leukocyte extravasation, respectively [Ginsberg et al, 2005;Luo et al, 2007]. Similarly, estrogen acts via GPER to promote the recruitment of integrin α5β1 to fibrillar adhesions, specialized adhesions sites that promote fibronectin fibril formation "fibrillogenesis" and ultimately, fibronectin matrix assembly and anchorage-independent growth [Quinn et al, 2009;Magruder et al, 2014]. Moreover, we have shown that integrin α5β1 is a necessary transmembrane signaling component for GPER dependent exoplasmic release of proHB-EGF suggests a common mechanism by which GPER may coordinate integrin-matrix adhesion, the assembly of a provisional fibronectin matrix and the local release of EGF-related polypeptides [Quinn et al, 2009;Magruder et al, 2014].…”

“…Similarly, estrogen acts via GPER to promote the recruitment of integrin α5β1 to fibrillar adhesions, specialized adhesions sites that promote fibronectin fibril formation "fibrillogenesis" and ultimately, fibronectin matrix assembly and anchorage-independent growth [Quinn et al, 2009;Magruder et al, 2014]. Moreover, we have shown that integrin α5β1 is a necessary transmembrane signaling component for GPER dependent exoplasmic release of proHB-EGF suggests a common mechanism by which GPER may coordinate integrin-matrix adhesion, the assembly of a provisional fibronectin matrix and the local release of EGF-related polypeptides [Quinn et al, 2009;Magruder et al, 2014]. As a consequence of its capacity to transactivate both integrin and EGFRs, GPER is strongly positioned to promote cellular survival responses, cell biological effects that fit well with the physiological and pathological processes that have been linked to GPER.…”

“…The ability of GPER to trigger release of local EGF-like polypeptides and synthesize a provisional extracellular matrix via requisite activation of integrin α5β1 [reviewed in Filardo, 2011] are a further reminder that GPER mediates its affects within the tumor microenvironment, and are likely important for the survival of infiltrating breast cancer cells that extravasate from mammary gland epithelia. Support for this concept is derived from the observation that GPER promotes estrogendependent fibrillogenesis and growth of breast cancer cells in an anchorage-free environment [Magruder et al, 2014], the best predictor of experimental metastasis in mice. Direct experimental evidence supporting the role for GPER in advanced breast cancer comes from a recent study by Prossnitz and colleagues that showed that extratumoral GPER expression is necessary for the growth, survival and metastasis of polyoma middle T (MT) driven breast cancer [Marjon et al, 2014].…”