Resolvin D2 Supports MCF-7 Cell Proliferation via Activation of Estrogen Receptor

Abstract

Inflammation has been implicated in tumor initiation, angiogenesis, and metastasis, and linked to the development of more aggressive, therapy-resistant estrogen receptor (ER)-positive breast cancer. Resolvin D2 (RvD2) is a potent anti-inflammatory lipid mediator. As RvD2 may be synthesized within breast tumors by both tumor cells and the surrounding stroma cells and is present in plasma at bioactive concentrations, we sought to characterize the impact of RvD2 on cell processes underlying breast tumor growth and spread. Trypan-blue exclusion, transfection with estrogen response element (ERE) reporter, real-time quantitative polymerase chain reaction, competitive radioligand binding assays, Western blotting, and immunofluorescence were the techniques used. Unexpectedly, whereas RvD2 (10-1000 nM) supported the proliferation of the ER-positive breast tumor (MCF-7) cells, it did not affect the ER-negative MDA-MB-231 cell number.The proliferative effect of RvD2 in MCF-7 cells was attenuated by the ER antagonist ICI 182,780 (7a-[9-[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]estra-1,3,5(10)-triene-3,17b-diol). Furthermore, RvD2 increased ERE transcriptional activity in a number of ER-positive breast and ovarian tumor cell lines. This activation was also inhibited by ICI 182,780. RvD2 altered the expression of a subset of estrogen-responsive genes. Although binding experiments showed that RvD2 did not directly compete with [ 3 H]17b-estradiol for ER binding, prior exposure of MCF-7 cells to RvD2 resulted in a significant reduction in the apparent cytosolic ER density. Confocal immunocytochemistry and Western blotting studies showed that RvD2 promoted nuclear localization of ERa. These observations indicate that RvD2 displays significant but indirect estrogenic properties and has the potential to play a role in estrogen-dependent breast cancer progression.

Glucocorticoid resistance of migration and gene expression in a daughter MDA-MB-231 breast tumour cell line selected for high metastatic potential

“…MDA-MB-231 and MCF-7 breast tumour cells (ATCC, Manassas, VA, USA) were cultured in phenol-red free RPMI 1640 and DMEM respectively supplemented with 10% (v/v) heat-inactivated fetal bovine serum (FCS), 2 mM L-glutamine, 1 mM nonessential amino acids, 1 mM sodium pyruvate, 15 mM HEPES solution, 100 U/mL penicillin and 100 μg/mL streptomycin as previously described5152. The highly metastatic MDA-MB-231-HM.LNm5 cell line was generated through a two-step process whereby a cell population initially selected by 6 cycles of transplanting spontaneous MDA-MB-231 pulmonary metastases to the mammary fat pad44 (designated MDA-MB-231-HM and kindly provided by ZM Shao and ZL Ou (Breast Cancer Institute, Fudan University, Shanghai, China) were inoculated into the mammary fat pad of a female BALB/c-SCID mouse, following which the axillary lymph node metastases were isolated.…”

Pro-Resolving Effects of Resolvin D2 in LTD4 and TNF-α Pre-Treated Human Bronchi

“…In normal and tumoural mammary tissues, enzymes involved in lipoxin A 4 and RvD 2 synthesis are expressed, with these lipid mediators also reported to display a crucial role in oestrogen-dependent breast cancer progression [38]. In human bronchial explants, it has been demonstrated that LXA 4 mediates beneficial effects via formyl-peptide receptor 2 signalling [39].…”

Specialised lipid mediators and their targets

“…Following treatment with TNF␣ and RvD1 attenuation of TNF␣ induced NF-B transcriptional activity was pronounced in cells overexpressing ALX/FPR2 and GPR32 [107]. Moreover, functionally overexpression of both receptors enhances RvD1 macrophage phagocytosis of PMNs, while knockout of such receptors attenuates such action [107] [110] have demonstrated RvD2 promoted proliferation of ER positive but not negative breast cancer cell lines. Intriguingly, binding experiments did not reveal RvD2 competing for oestrogen receptor (ER) binding in the presence of estradiol, while they did show RvD2 promoted redistribution of ER␣ expression, moving from cytoplasmic to nucleus [110].…”

“…Moreover, functionally overexpression of both receptors enhances RvD1 macrophage phagocytosis of PMNs, while knockout of such receptors attenuates such action [107] [110] have demonstrated RvD2 promoted proliferation of ER positive but not negative breast cancer cell lines. Intriguingly, binding experiments did not reveal RvD2 competing for oestrogen receptor (ER) binding in the presence of estradiol, while they did show RvD2 promoted redistribution of ER␣ expression, moving from cytoplasmic to nucleus [110]. These findings highlight the importance of understanding the molecular mechanisms underlying cellular responses to these agents to facilitate the development of safe and effective therapeutics.…”