Faslodex Inhibits Estradiol-Induced Extracellular Matrix Dynamics and Lung Metastasis in a Model of Lymphangioleiomyomatosis

Abstract

Lymphangioleiomyomatosis (LAM) is a destructive lung disease primarily affecting women. Genetic studies indicate that LAM cells carry inactivating tuberous sclerosis complex (TSC)-2 mutations, and metastasize to the lung. We previously discovered that estradiol increases the metastasis of TSC2-deficient cells in mice carrying xenograft tumors. Here, we investigate the molecular basis underlying the estradiol-induced lung metastasis of TSC2-deficient cells, and test the efficacy of Faslodex (an estrogen receptor antagonist) in a preclinical model of LAM. We used a xenograft tumor model in which estradiol induces the lung metastasis of TSC2-deficient cells. We analyzed the impact of Faslodex on tumor size, the extracellular matrix organization, the expression of matrix metalloproteinase (MMP)-2, and lung metastasis. We also examined the effects of estradiol and Faslodex on MMP2 expression and activity in tuberindeficient cells in vitro. Estradiol resulted in a marked reduction of Type IV collagen deposition in xenograft tumors, associated with 2-fold greater MMP2 concentrations compared with placebotreated mice. Faslodex normalized the Type IV collagen changes in xenograft tumors, enhanced the survival of the mice, and completely blocked lung metastases. In vitro, estradiol enhanced MMP2 transcripts, protein accumulation, and activity. These estradiol-induced changes in MMP2 were blocked by Faslodex. In TSC2-deficient cells, estradiol increased MMP2 concentrations in vitro and in vivo, and induced extracellular matrix remodeling. Faslodex inhibits the estradiol-induced lung metastasis of TSC2-deficient cells. Targeting estrogen receptors with Faslodex may be of efficacy in the treatment of LAM.Keywords: tuberin; estrogen receptor antagonist; matrix metalloproteinase; extracellular matrix Lymphangioleiomyomatosis (LAM) is a progressive and destructive pulmonary disease with a striking gender predisposition, affecting women almost exclusively. Pathologically, LAM is characterized by the diffuse proliferation of abnormal smooth muscle cells and by the cystic destruction of the lung parenchyma (1-4). LAM occurs in 30 to 40% of women with tuberous sclerosis complex (TSC) (5, 6). In a series of patients at the Mayo Clinic, LAM was the third most frequent cause of TSC-related death, after renal disease and brain tumors (7). LAM can also occur in women who do not have germline mutations in the genes TSC1 or TSC2 ("sporadic LAM"). Inactivating mutations of both alleles in the TSC1 or TSC2 gene have been found in LAM cells from patients with both TSC LAM and sporadic LAM (8, 9).About 60% of women with the sporadic form of LAM also demonstrate renal angiomyolipomas. The presence of TSC2 mutations in LAM cells and renal angiomyolipoma cells from women with sporadic LAM, but not in normal tissue, has led to the hypothesis that LAM cells spread to the lungs via a metastatic mechanism, although LAM cells possess a histologically benign appearance (8, 10). The only proven treatment for endstage LAM is lung transplantation, which ...

Towards personalised therapy for lymphangioleiomyomatosis: lessons from cancer

“…In TSC2-deficient cells, 17-b oestradiol increases cell size, and promotes cell survival, metastasis and lung colonisation via mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)-dependent pathways [20][21][22][23]. Oestradiol also induces the expression and activity of matrix metalloproteinase-2 in TSC2-deficient cells, which may contribute to lung destruction [20,24].…”

“…Oestradiol also induces the expression and activity of matrix metalloproteinase-2 in TSC2-deficient cells, which may contribute to lung destruction [20,24]. The prometastatic effects of oestradiol on TSC2-deficient cells can be blocked, in vitro and in vivo, by the US Food and Drug Administration approved agent fulvestrant (Faslodex; AstraZeneca, London, UK) [20], which leads to degradation of ER-a.…”

“…Complete disease remissions have not been observed in TSC2-deficient angiomyolipomas or subependymal giant cell astrocytomas treated with rapalogues. Pre-clinical studies indicate that targeting hormonal stimuli in LAM with agents such as fulvestrant, which lack oestrogen agonist activity, could have therapeutic benefit [20]. In metastatic breast and prostate cancer, hormonally targeted therapy can lead to complete remission.…”

Treatment of lymphangioleiomyomatosis: building evidence in orphan diseases

“…Some of these difficulties were shared by previous studies conducted in this and other rare diseases. LAM research is currently very active, with several clinical trials ongoing or in preparation using aromatase inhibitors or the agent fulvestrant (which targets the oestrogen receptor-a [30,48,49]), targeting autophagy [50] or using simvastatin in combination with sirolimus [51,52]. VEGF-D [53], or its receptor VEGFR-3, Rheb [30], integrins, etc., may also represent effective targets for therapy.…”

Proapoptotic protein Bim attenuates estrogen-enhanced survival in lymphangioleiomyomatosis

“…Little is known about the molecular mechanisms underlying E 2 -induced survival and metastasis of tuberin-deficient cells. The impact of E 2 on the growth of tuberin-deficient cells has been reported (9,(33)(34)(35)(36)(37)(38)(39)(40). Gu et al reported that E 2 activates Erk1/2 and increases the migration and invasion of tuberin-deficient cells (41).…”