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- Title
Estrone Sulfate Transport and Steroid Sulfatase Activity in Colorectal Cancer: Implications for Hormone Replacement Therapy.
- Authors
Gilligan, Lorna C.; Gondal, Ali; Tang, Vivien; Hussain, Maryam T.; Arvaniti, Anastasia; Hewitt, Anne-Marie; Foster, Paul A.
- Abstract
Hormone replacement therapy (HRT) affects the incidence and potential progression of colorectal cancer (CRC). As HRT primarily consists of estrone sulfate (E1S), understanding whether this conjugated estrogen is transported and metabolized in CRC will define its potential effect in this malignancy. Here, we show that a panel of CRC cell lines (Colo205, Caco2, HCT116, HT-29) have steroid sulfatase (STS) activity, and thus can hydrolyze EE1S. STS activity is significantly higher in CRC cell lysate, suggesting the importance of EE1S transport in intracellular STS substrate availability. As EE1S transport is regulated by the expression pattern of certain solute carrier organic anion transporter polypeptides, we show that in CRC OATP4A1 is the most abundantly expressed transporter. All four CRC cell lines rapidly transported EE1S into cells, with this effect significantly inhibited by the competitive OATP inhibitor BSP. Transient knockdown of OATP4A1 significantly disrupted EE1S uptake. Examination of estrogen receptor status showed ERa was present in Colo205 and Caco2 cells. None of the cells expressed ERb. Intriguingly, HCT116 and HT29 cells strongly expressed the G protein coupled estrogen receptor (GPER), and that stimulation of this receptor with estradiol (E2) and G1, a GPER agonist, significantly (p < 0.01) increased STS activity. Furthermore, tamoxifen and fulvestrant, known GPER agonist, also increased CRC STS activity, with this effect inhibited by the GPER antagonist G15. These results suggest that CRC can take up and hydrolyze EE1S, and that subsequent GPER stimulation increases STS activity in a potentially novel positive feedback loop. As elevated STS expression is associated with poor prognosis in CRC, these results suggest HRT, tamoxifen and fulvestrant may negatively impact CRC patient outcomes.
- Subjects
ESTRONE; THERAPEUTIC use of steroid hormones; COLON cancer treatment
- Publication
Frontiers in Pharmacology, 2017, Vol 8, p1
- ISSN
1663-9812
- Publication type
Article
- DOI
10.3389/fphar.2017.00103