Estrogen Activation by Steroid Sulfatase Increases Colorectal Cancer Proliferation via GPER

Abstract

Context:Estrogens affect the incidence and progression of colorectal cancer (CRC), although the precise molecular mechanisms remain ill-defined.Objective:The present study investigated prereceptor estrogen metabolism through steroid sulphatase (STS) and 17β-hydroxysteroid dehydrogenase activity and subsequent nongenomic estrogen signaling in human CRC tissue, in The Cancer Genome Atlas colon adenocarcinoma data set, and in in vitro and in vivo CRC models. We aimed to define and therapeutically target pathways through which estrogens alter CRC proliferation and progression.Design, Setting, Patients, and Interventions:Human CRC samples with normal tissue-matched controls were collected from postmenopausal female and age-matched male patients. Estrogen metabolism enzymes and nongenomic downstream signaling pathways were determined. CRC cell lines were transfected with STS and cultured for in vitro and in vivo analysis. Estrogen metabolism was determined using an ultra-performance liquid chromatography–tandem mass spectrometry method.Primary Outcome Measure:The proliferative effects of estrogen metabolism were evaluated using 5-bromo-2′-deoxyuridine assays and CRC mouse xenograft studies.Results:Human CRC exhibits dysregulated estrogen metabolism, favoring estradiol synthesis. The activity of STS, the fundamental enzyme that activates conjugated estrogens, is significantly (P < 0.001) elevated in human CRC compared with matched controls. STS overexpression accelerates CRC proliferation in in vitro and in vivo models, with STS inhibition an effective treatment. We defined a G-protein–coupled estrogen receptor (GPER) proproliferative pathway potentially through increased expression of connective tissue growth factor in CRC.Conclusion:Human CRC favors estradiol synthesis to augment proliferation via GPER stimulation. Further research is required regarding whether estrogen replacement therapy should be used with caution in patients at high risk of developing CRC.

Oestrogens Stimulate Proliferation in Colorectal Cancer via GPER and the Hippo signalling pathway

“…The results showed no significant alteration in CTGF gene expression levels ( Figure 10). However, previous experiments in our lab had evidenced that GPER stimulation after E2 and G1 (100nM) treatment leads to CTGF upregulation and elevated protein expression in HCT116 and HT29 cells 37 . The controversy between the results may be due to different passage number of the cells examined.…”

“…Previous projects in the lab have shown that steroid sulphatase (STS), the enzyme that converts conjugated oestrogens to their active forms 50 , is significantly upregulated in human CRC tissue leading to increased availability of active oestrogen. Furthermore, the increase in STS activity substantiated greater CRC tumour burden in mouse models 37 . However, the role of oestrogen is regulated apart from their amount and the presence or absence of oestrogen receptors that mediate their action.…”

“…Published data from our lab support the fact that GPER mRNA levels are decreased in human CRC tissue compared to matched normal tissue. However, GPER protein levels were reported to be raised in human CRC tissue compared to matched normal control implying that GPER protein degradation pathways possibly alter in CRC, permitting GPER protein retention 37 .…”

“…A big controversy came in 1994 after a case-controlled study implicating Hormone Replacement Therapy (HRT) (conjugated oestrogen [oestrone sulfate (E1S)] plus medroxyprogesterone) as protective against CRC development in postmenopausal women 36,37 . In the following years, further human studies were warranted from the Women's Health…”

“…Hence, the loss of ERβ is seen by some as the oestrogenic switch in CRC that leads to the loss of the anti-proliferative effects of oestrogen.Despite the established role of the two classic ERs, the effect of oestrogen in CRC through the latest discovered ER, GPER, remains unclear. GPER is a typical seven-transmembrane G protein-coupled receptor, widely expressed in the body, with high affinity to E2 at physiological concentrations37 . It emerged at the forefront of the scientific interest after Anastasia ArvanitiFilardo and colleagues revealed that it promotes rapid oestrogen-induced activation of ERK1/ERK2 independently of ERα and ERβ action in breast cancer cells 63 .…”