MINI REVIEW article

Front. Endocrinol., 26 January 2021

Sec. Molecular and Structural Endocrinology

Volume 11 - 2020 | https://doi.org/10.3389/fendo.2020.600404

GPER and Testicular Germ Cell Cancer

  • 1. Université Côte d’Azur, CHU, INSERM U1065, C3M, Nice, France

  • 2. Université Côte d’Azur, INSERM U1065, C3M, Nice, France

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Abstract

The G protein-coupled estrogen receptor (GPER), also known as GPR30, is a widely conserved 7-transmembrane-domain protein which has been identified as a novel 17β-estradiol-binding protein that is structurally distinct from the classic oestrogen receptors (ERα and ERβ). There are still conflicting data regarding the exact role and the natural ligand of GPER/GPR30 in reproductive tracts as both male and female knock-out mice are fertile and have no abnormalities of reproductive organs. Testicular germ cell cancers (TGCCs) are the most common malignancy in young males and the most frequent cause of death from solid tumors in this age group. Clinical and experimental studies suggested that estrogens participate in the physiological and pathological control of male germ cell proliferation. In human seminoma cell line, while 17β-estradiol (E2) inhibits in vitro cell proliferation through an ERβ-dependent mechanism, an impermeable E2 conjugate (E2 coupled to BSA), in vitro cell proliferation is stimulated by activating ERK1/2 and protein kinase A through a membrane GPCR that we further identified as GPER/GPR30. The same effect was observed with low but environmentally relevant doses of BPA, an estrogenic endocrine disrupting compound. Furthermore, GPER/GPR30 is specifically overexpressed in seminomas but not in non-seminomas and this overexpression is correlated with an ERβ-downregulation. This GPER/GPR30 overexpression could be linked to some genetic variations, as single nucleotide polymorphisms, which was also reported in other hormone-dependent cancers. We will review here the implication of GPER/GPR30 in TGCCs pathophysiology and the arguments to consider GPER/GPR30 as a potential therapeutic target in humans.

Introduction

Although relatively rare, testicular germ cell cancers (TGCC) are the most frequent solid cancer in young people (1, 2). Seminomas represent the most frequent histological form, occurring alone or associated with non-seminoma forms in 50-75% of cases (1, 2). Incidence rates of TGCC have been increasing worldwide for several decades (3, 4).

Risk factors for TGCC are described in Table 1 and are mainly genetic. Indeed, incidence of TGCC is significantly increased in brothers and sons of TGCC patients (5, 7). Consistent with many epidemiological studies, gene variants that might predispose an individual to TGCC were identified by genome-wide association studies (GWAS) (8, 9). These variants included common variations on 12q22 in the KITLG gene, but also on PDE11A, BAK1, SPRY, DMRT1, DAZL, and PRDM14 [reviewed in (10)]. Other classical risk factors are cryptorchidism (or undescended testis), inguinal hernia, and all sexual differentiation disorders (6, 11) (Table 1).

Table 1

Risk FactorRisk estimate or range Odd Ratio (95% CI)
Low birth weight (versus normal)1.34 (1.08 – 1.67)
Low gestational age (versus not low)1.31 (1.07 – 1.59)
Cryptorchidism4.30 (3.62 – 5.11)
Inguinal hernia1.63 (1.37 – 1.94)
Twinning1.22 (1.03 – 1.44)
Prior TGCC12.4 (11.0 – 13.9)
Father with TGCC3.78 (1.94 – 6.63)
Brother with TGCC12.74 (6.38 – 22.64)
Adult height (per 5 cm increase)1.13 (1.07 – 1.19)

Usual risk factors of testicular germ cell cancers.

TGCC, testicular germ cell cancers.

Adapted from Cook MB. et al. (5). and Mc Glynn KA. et al. (6).

TGCC are considered to derive from a precursor lesion named “carcinoma in situ of the testis” or “germ cell neoplasia in situ” (GCNIS) (12). This lesion is present before birth, arising from the fetal germ cells (i.e. the gonocytes), and is reactivated after puberty under physiological hormonal stimulation (13). Epidemiological and clinical data have suggested that the increase of TGCC incidence could be related to environmental factors such as fetal exposure to endocrine disruptors (EDCs) with anti-androgenic and/or estrogenic effects (14, 15). However, this hypothesis supposes that TGCCs are estrogen-dependent tumors. In this review, we analyze the implication of classical and non-classical (GPER/GPR30) estrogen receptors in normal and malignant germ cells and the regulation of cell proliferation by xeno-estrogens and discuss how GPER/GPR30 could be considered as a potential therapeutic target in humans.

Could TGCC Be a Hormone-Dependent Cancer?

Environmental Features

Several studies have reported abnormalities of male genital tracts in animals that were accidently exposed to endocrine disruptors, such as hypospadias and cryptorchidism in alligators (16) or panthers (17), especially in the case of exposition to the organochloride dichlorodiphenyltrichloroethane (DDT) or its metabolites (DDE, DDD), which exhibit estrogenic properties. However, there is actually no animal model of TGCC, except for transgenic mice with targeted overexpression of GDNF in spermatogonia (18).

In humans, early fetal exposure to diethylstilbestrol (DES), a synthetic estrogen used during the 1960’s, was responsible for an increased incidence rate of cryptorchidism and hypofertility by impairment of sperm quality in sons and in grandsons (19, 20). Such an exposure was also suggested to be responsible for the occurrence of TGCC in the offspring of two meta-analysis (21, 22). In past studies, the association between occupational exposure and risk to develop TGCC (2325) was well-documented and offered suggestive or strong arguments. However, more recent epidemiological case-control studies reported conflicting data for fetal exposure to p,p′-DDT (estrogenic compound) or to p,p′-DDE (a stable metabolite of DDT with antiandrogenic properties) (2631).

Estrogens and Normal Germ Cells

Testicular concentrations of 17β-estradiol (E2) are 10 to 100 times higher than those measured in blood (32). E2 is produced after testosterone conversion by aromatase in all mammalian testes, including humans (33). Estrogens are essential for spermatogenesis control but the type of estrogen receptors involved and the molecular mechanisms by which estrogens may precisely act during spermatogenesis still remain incompletely understood (34).

Expression of classical and non-classical estrogen receptors expression in mammalian testes is well-established. It exhibits some species specificity and some controversial results, especially in humans [reviewed in (35)]. Indeed, in humans, the classical nuclear estrogen receptor ERβ has been clearly identified in most germ cells, including fetal gonocytes (36), neonatal, prepubertal (37), and adult spermatogonia (38), while ERα is not expressed in human gonocytes (36) or neonatal or prepubertal spermatogonia (37). However, data concerning the expression of ERα by male germ cells are inconsistent, as some authors reported an expression in elongated spermatids and mature spermatozoa (39) and others did not find any expression of ERα at all (38, 40). In fact, these inconsistent observations could be due to the existence of a truncated isoform of ERα lacking exon 1, called ERα46, which has been identified in human adult spermatozoa (41). This isoform could participate in non-genomic membrane signaling. Indeed, one reported case of a man with an inactivating mutation of ERα gene was associated with a normal sperm count but with completely abnormal motility (42).

GPER/GPR30 and Testis

GPR30 is a widely conserved orphan GPCR, which has been renamed as G protein-coupled estrogen receptor (GPER) (HUGO & MGI Databases). It is a seven-transmembrane domain protein, identified for the first time in a triple-negative breast cancer cell line, that can bind E2 and other estrogenic compounds independently of the classic estrogen receptors (ERα and ERβ). The precise subcellular localization of GPER/GPR30 is still a matter of debate as it has been detected at the plasma membrane but also in the endoplasmic reticulum and Golgi apparatus (43).

GPER/GPR30 has been identified in numerous rodents and human estrogen targets normal or malignant tissues where it can mediate rapid E2-induced non genomic signaling events (43). GPER/GPR30 can activate cell proliferation through several signaling pathways involving MAP kinases, ERK1/2, and PI3K pathways (44, 45) but also microRNA regulation (4648), EGFR transactivation (49, 50), HIF induced pathway (51, 52), IGF-R pathway (53, 54), NF-kB pathway (55, 56), and crosstalk with other receptors (classical or truncated estrogen receptors, or other steroids receptors) (5759). Within those pathways, the activation of ERK1/2 is undoubtedly the most consistent pathway across cell types and is usually considered as a key factor in cancer prognosis.

Analyzing normal human testes from a fertile man, we previously reported that GPER/GPR30 was expressed by both somatic (Sertoli and Leydig cells) and germ cells (60). Amazingly, Rago et al. (61). reported a negative staining in adult germ cells, probably due to the use of abnormal granulomatous testes. As expression of GPER/GPR30 in human fetal gonocytes has not yet been studied; it could be possible that only immature germ cells and gonocytes express GPER/GPR30, explaining these inconsistent data [reviewed in (62)].

Estrogens, Germ Cells Proliferation, and TGCC

Estrogen Receptors and Malignant Germ Cells

Estrogen receptor expression is a well-recognized prognosis factor of estrogen-dependent cancers, especially in the case of breast cancer (6365). Several teams have suggested that TGCCs could be estrogen-dependent cancers as they express both ERβ and GPER/GPR30 (6670). We previously reported in a large cohort of TGCCs that GPER/GPR30 was overexpressed only in seminoma but not in non-seminoma tumors (60) and promoted seminoma cell proliferation (71). Pais et al. (72) reported that expression of ERβ was decreased in seminoma but remained high in teratomas. In the same way, Boscia et al. (69) showed that ERβ was downregulated in seminomas and reported a negative association between the expression of ERβ and GPER/GPR30 protein. This inverse receptor expression pattern could reflect a switch in estrogen responsiveness from a suppressive (66) to a promoting profile (60, 67), as it has also been observed in other estrogen-dependent cancers and was correlated to a poorer prognosis (6365).

Genetic factors could of course explain this specific profile of expression. Variants of ERβ were explored but studies reported inconsistent data. Ferlin et al. (73) reported a weak but not significant association between one variant for ERβ and an increase risk of TGCC in Italian men, while Brokken et al. (74) described exactly the opposite in a cohort of 367 Nordic patients with TGCC and two other variants of the ERβ. In our large cohort of 169 TGCCs, we were able to describe that seminomas were characterized by a loss of homozygous ancestral genotype concerning two polymorphisms located in the promoter region of GPER/GPR30 (75). We assumed that this genotype could explain a part of GPER/GPR30 overexpression in seminomas. This expression profile could also be determined by epigenetic modulation of ERβ and GPER/GPR30 genes (low expression of ERβ due to an hypermethylation of its promoter and high expression of GPER/GPR30 gene due to an hypomethylation of its promoter). Indeed, fetal exposure to EDCs is supposed to induce such epigenetic modulation as reported, for example, by Zama et al. (76) who reported that fetal and neonatal exposure to the endocrine disruptor methoxychlor was responsible for a down regulation of ovarian ERβ gene expression.

Anway et al. (77) were the first to observe and to report several epigenetic modifications in rodent DNA male germ cells after gestational exposure to vinclozolin (antiandrogenic compound) or methoxychlor (estrogenic compound). These data have been recently confirmed by Dumasia et al. (78) for xenoestrogens signaling through ERβ. Since this first publication of Anway et al. (77) DNA methylation (hyper- and hypo-) (79, 80), onco-miRNAs expression (miR 371-373) (81, 82), or chromatin modifications have been reported in TGCC (83). However, even if experimental data in rodents suggested that these epigenetic modifications might be induced by fetal exposure to EDCs, it remains to be proven that such epigenetic modifications exist in humans and can be induced by fetal exposure to EDCs.

Putative Role of GPER/GPR30 in Malignant Germ Cells

JKT-1 cell line is derived from a human testicular seminoma (84), which expressed functional aromatase (66) and is able to convert testosterone into E2 and as well as ERβ, but not ERα. At physiological concentrations (10-7 to 10-9 M), we previously reported that E2 was able to inhibit in vitro JKT-1 cell proliferation involving an ERβ pathway (66). We conjugated E2 to bovine serum albumin (E2-BSA) for the purpose that E2 cannot cross the plasma membrane and then cannot link to its canonical receptor ERβ. In this condition, E2-BSA at the same concentrations (10-7 to 10-9 M) stimulated in vitro JKT-1 cell proliferation by activating the ERK1/2 and PKA pathways. E2-BSA is responsible for a rapid (15 min) phosphorylation of CREB. This effect was not inhibited by ICI-182,780, an antagonist of ERβ, but by Pertussis toxin, suggestive of the involvement of a membrane G-protein-coupled receptor (GPCR). Similar results were obtained with bisphenol A (BPA) at low and very low (nM to pM) concentrations (85), the levels already found in male cord blood and in more than 95% of the worldwide population (86, 87).

Among EDCs, BPA is especially a matter of concern as populations exhibit worldwide with detectable blood and/or urine levels of BPA (86), and so it is used as a monomer to manufacture a wide range of objects containing polycarbonate plastic and resins. BPA is considered an estrogenic EDC and is recognized as a substance of very high concern (SVHC) by the European Chemicals Agency (ECHA) because several experimentations and data reported that it is involved in developmental, reproductive, and malignant diseases by mimicking the natural hormone E2 and by interfering with endogenous pathways at selective periods, especially during fetal life (88). However, BPA exhibits a weak affinity for the classical ERs, which is 1,000–2,000 times lower than E2. Thus, it has been suggested that BPA could act through other receptors than classical ERs, for example GPER/GPR30, PPARγ gamma, or ERRγ gamma (88).

In our JKT-1 seminoma cells model, we were able to identify the GPCR involved in the promoting action of E2-BSA and BPA as GPER/GPR30 (71). Indeed, the BPA-induced promotive effect was mimicked by G1 alone, a specific agonist of GPER/GPR30, while it was totally inhibited by G15, a partial antagonist of GPER/GPR30, as well as a selective anti-GPER/GPR30 siRNA (Figure 1A) (60, 71). This GPER/GPR30-mediated signaling of BPA was also reported in other hormone-dependent tumors. For example, Pupo et al. (90) reported that BPA could increase the proliferation of SKBr3 breast cancer cells, which lack the classical ERs, through a GPER/GPR30-EGFR/ERK transduction pathway.

Figure 1

Interestingly, the dose-response curve that we obtained for BPA in our model was non-monotonic and showed an inverted U-shape curve (Figure 1B). Non-monotonic dose response curves (NMDRC) have already been reported and well-documented for natural hormones. NMDRC have also been suggested for EDCs, especially in the case of BPA, but there are few consistent data available in the literature (91). Most authors explained that these atypical dose-response curves resulted from the complex interactions between the ligand (i.e., the natural hormone or an EDC) and a hormone receptor. In our model, it could, for example, be explained by the resultant of the double opposite effect of BPA on ERβ and GPER/GPR30 (60, 85). Indeed, at low doses (nM or pM), BPA acts only through GPER/GPR30 by a promotive effect while it acts also through ERβ at higher dose (mM), which counteracted the promotive GPER/GPR30-mediated effect (66). In order to confirm this hypothesis, we exposed JKT-1 cells to variable doses of BPA together with a fixed dose of E2. The BPA dose-response curve that we obtained kept its inverted U-shape aspect but was down-translated, confirming that BPA can act either through ERβ or GPER/GPR30 depending on the other estrogenic compounds that are present in the cell environment. This parameter is particularly important to consider since in most cases we are exposed to EDC mixtures.

Furthermore, in the same cellular model, the effects of several EDCs on in vitro proliferation were totally different and dependent on the resultant of the two expressed receptors, ERβ and GPER/GPR30. For example, atrazine, another estrogenic pesticide, induced a suppressive effect on seminoma cell proliferation in vitro involving a GPER/GPR30-dependent pathway (92). In the same way, an alkylphenol mix promoted seminoma cell proliferation through a GPER/GPR30-dependent pathway (93). However, in this case, the promoting effect is also mediated through ERα36, which is a truncated form of the canonical ERα66 (without both transcriptional activation domains (AF-1 and AF-2)) and was first described first by Wang et al. (94) in 2005. It seems to participate in non-genomic estrogen signaling concurrently to and/or associated with GPER/GPR30, as demonstrated in breast cancer cell lines (94) and in seminoma-like TCam-2 cell line (95). Thus, the presence of ERα36 in tumors is an important parameter to consider before considering selective antagonists of GPER/GPR30 as a therapeutic target in TGCC or other estrogen-dependent cancers.

The crosstalk among GPER/GPR30 signaling, classical estrogen receptors, and other nuclear receptors involved in testis physiology regulation is also important to consider (96). Through such interactions, GPER/GPR30 could probably modulate the tumor microenvironment and through this mediate TGCC progression and aggressiveness, especially by inducing epithelial-mesenchymal-transition (97, 98), as has been reported in breast cancer (98, 99) and in pancreatic adenocarcinoma (100).

Could GPER/GPR30 Constitute a Potential Therapeutic Target for TGCC?

Accumulating evidence supports the role of GPER/GPR30 in cancer progression and metastasis in estrogen-dependent cancers (especially in breast cancer), even though GPER/GPR30 signaling can differently affect the development of cancer depending on the type of tissue, but also in the same tissue depending on the type of ligand (92). A better comprehension of the molecular pathways involved in TGCC development, in particular the role of GPER/GPR30 in tumor progression, points out new tools like agonists or antagonists of GPER/GPR30, which could be used going forward by clinicians to target cancer cells and improve the patient’s chance of survival (68, 101).

Three pharmacological GPER/GPR30-ligands were routinely available to study GPER/GPR30 functions. The first one, G-1, was identified by Bologa in 2006 and is a specific agonist of GPER/GPR30, while G-15 and G-36, identified respectively in 2009 and 2011 by Dennis, are GPER/GPR30 antagonists. However, G-15 exhibits a partial cross-reactivity with ERα explaining why G-36 is mainly used in the study of GPER/GPR30 (102). Other pharmacological ligands were synthetized (GPER/GPR30-L1 and GPER/GPR30-L2) (102, 103) but they exhibit variable affinities for GPER/GPR30 and potential cross-reactivity with classical ERs, explaining why they cannot be considered as therapeutic tools at this time (104). These small molecules were used especially in vitro, as we did with seminoma cells; in our model, G-1 was able to mimic the proliferative effect of BPA while G-15 neutralized this effect and reduced cell proliferation in the presence of BPA (71). Thus, G-15 may be a helpful adjuvant in the treatment of TGCC. Nevertheless, to date, no studies have reported the use of GPER/GPR30 antagonists in this way.

However, agonists and antagonists of GPER/GPR30 were tested in the treatment of other tumors. For example, as we observed in vitro in seminoma cells, G-15 was also able to decrease the in vitro proliferation of non-small cell lung cancer (105) while G-1 was reported to induce malignant cell proliferation, invasion, and migration in primary cultured lung cancer cells (106) and in ER-negative breast cancer cells (107, 108) involving SIRT1 (108). At the opposite end, G-1 was able to decrease in vivo the tumor volume of pancreatic ductal adenocarcinoma in mice (109) and of adrenocortical carcinoma in a xenograft model (110, 111).

Interestingly, G-1 was also able to reduce the side effects of chemotherapy, as, for example, the cardiac toxicity of doxorubicin is usually used as an adjuvant therapy in breast cancer (112). This beneficial effect is related to the well-documented GPER/GPR30 actions on the vascular system, involving in this specific case the Nox1 pathway, which could constitute new therapeutic tools (113, 114).

Actually, only one clinical study is registered in Clinical Trials involving a GPER/GPR30 agonist. The NCT04130516 is a phase 1, first-in-human, open-label, multicenter study (up to six study sites in the United States) designed to characterize the safety, tolerability, and antitumor effects of LNS8801 administered orally in patients with advanced cancer (solid tumor or lymphoma). The recruitment is still on-going, and the estimated primary completion date is the end of 2021.

Finally, even though GPER/GPR30 modulation represents a potential novel strategy in cancer therapy, there remains a lack of solid clinical evidence supporting the specificity of GPER/GPR30 antagonists, especially in TGCC.

When compared with normal tissues, GPER/GPR30 is highly expressed in breast cancer and its high expression at the plasma membrane is strongly correlated with a poor prognosis, especially in triple negative tumors (115). This overexpression of GPER/GPR30 was also related to tamoxifen resistance (116, 117). Thus, GPER/GPR30 could be considered as a potential therapeutic target in such estrogen-dependent cancers.

Conclusion

Since its discovery in breast cancer, the role of GPER/GPR30 in estrogen-dependent malignancies has been of great interest. TGCC, the most common solid cancer in young men, expresses classical estrogen receptors (ERβ) but also GPER/GPR30. While E2 is responsible for a suppressive effect through an ERβ-dependent pathway, EDCs like BPA could induce in vitro seminoma cell proliferation by binding to GPER/GPR30. Furthermore, GPER/GPR30 is overexpressed in seminoma, probably due to genetic and/or epigenetic modulations that could be induced by fetal exposure to some EDCs. As proposed by Skakkebaek (4), an estrogenic environment might impair normal differentiation and proliferation of normal fetal, perinatal, and peripubertal germ stem cells, and then predispose an individual to TGCC, meaning it may be considered as an estrogen-dependent cancer. In our model, we have showed that G-15, a partial antagonist of GPER/GPR30, was able to reduce in vitro the BPA-induced cell proliferation (71) and may constitute a potential adjuvant in the treatment of TGCC. However, there remains a lack of solid clinical evidence to consider its clinical use. Direct regulation of GPER/GPR30 expression by siRNA silencing and/or nanotechnology could offer, at last, another tool to target GPER/GPR30 in cancer therapy.

Funding

This work was supported by the Société Française d’Endocrinologie (SFE), the Institut National de la Santé et de la Recherche (INSERM), and the Fondation pour la Recherche Médicale (FRM) (to NC).

Statements

Author contributions

NC and PF designed the study and contributed to the discussions and manuscript. NC and RP-B researched and interpreted data. SC and CH contributed to discussions and manuscript. All authors contributed to the article and approved the submitted version.

Acknowledgments

The authors greatly acknowledge Eric R. Prossnitz, Ph.D. (University of New Mexico, Albuquerque, USA) for kindly providing the selective GPER/GPR30 antagonist G15.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

References

  • 1

    BoslGJMotzerRJ. Testicular germ-cell cancer. New Engl J Med (1997) 337(4):242–53. doi: 10.1056/NEJM199707243370406

  • 2

    BrayFRichiardiLEkbomAPukkalaECuninkovaMMollerH. Trends in testicular cancer incidence and mortality in 22 European countries: continuing increases in incidence and declines in mortality. Int J Cancer (2006) 118(12):3099–111. doi: 10.1002/ijc.21747

  • 3

    Le CornetCLortet-TieulentJFormanDBerangerRFlechonAFerversBet al. Testicular cancer incidence to rise by 25% by 2025 in Europe? Model-based predictions in 40 countries using population-based registry data. Eur J Cancer (2014) 50(4):831–9. doi: 10.1016/j.ejca.2013.11.035

  • 4

    SkakkebaekNE. A Brief Review of the Link between Environment and Male Reproductive Health: Lessons from Studies of Testicular Germ Cell Cancer. Hormone Res Paediatrics (2016) 86(4):240–6. doi: 10.1159/000443400

  • 5

    CookMBAkreOFormanDMadiganMPRichiardiLMcGlynnKA. A systematic review and meta-analysis of perinatal variables in relation to the risk of testicular cancer–experiences of the son. Int J Epidemiol (2010) 39(6):1605–18. doi: 10.1093/ije/dyq120

  • 6

    McGlynnKATrabertB. Adolescent and adult risk factors for testicular cancer. Nat Rev Urol (2012) 9(6):339–49. doi: 10.1038/nrurol.2012.61

  • 7

    HemminkiKChenB. Familial risks in testicular cancer as aetiological clues. Int J Androl (2006) 29(1):205–10. doi: 10.1111/j.1365-2605.2005.00599.x

  • 8

    RapleyEATurnbullCAl OlamaAADermitzakisETLingerRHuddartRAet al. A genome-wide association study of testicular germ cell tumor. Nat Genet (2009) 41(7):807–10. doi: 10.1038/ng.394

  • 9

    FerlinAPengoMPizzolDCarraroUFrigoACForestaC. Variants in KITLG predispose to testicular germ cell cancer independently from spermatogenic function. Endocrine-Related Cancer (2012) 19(1):101–8. doi: 10.1530/ERC-11-0340

  • 10

    XingJSBaiZM. Is testicular dysgenesis syndrome a genetic, endocrine, or environmental disease, or an unexplained reproductive disorder? Life Sci (2018) 194:120–9. doi: 10.1016/j.lfs.2017.11.039

  • 11

    CookMBAkreOFormanDMadiganMPRichiardiLMcGlynnKA. A systematic review and meta-analysis of perinatal variables in relation to the risk of testicular cancer–experiences of the mother. Int J Epidemiol (2009) 38(6):1532–42. doi: 10.1093/ije/dyp287

  • 12

    SkakkebaekNE. Possible carcinoma-in-situ of the testis. Lancet (1972) 2(7776):516–7. doi: 10.1016/s0140-6736(72)91909-5

  • 13

    SonneSBAlmstrupKDalgaardMJunckerASEdsgardDRubanLet al. Analysis of gene expression profiles of microdissected cell populations indicates that testicular carcinoma in situ is an arrested gonocyte. Cancer Res (2009) 69(12):5241–50. doi: 10.1158/0008-5472.CAN-08-4554

  • 14

    OlesenIASonneSBHoei-HansenCERajpert-De MeytsESkakkebaekNE. Environment, testicular dysgenesis and carcinoma in situ testis. Best Pract Res Clin Endocrinol Metab (2007) 21(3):462–78. doi: 10.1016/j.beem.2007.04.002

  • 15

    LymperiSGiwercmanA. Endocrine disruptors and testicular function. Metabol: Clin Exp (2018) 86:7990. doi: 10.1016/j.metabol.2018.03.022

  • 16

    GuilletteLJJr.GrossTSMassonGRMatterJMPercivalHFWoodwardAR. Developmental abnormalities of the gonad and abnormal sex hormone concentrations in juvenile alligators from contaminated and control lakes in Florida. Environ Health Perspect (1994) 102(8):680–8. doi: 10.1289/ehp.94102680

  • 17

    FacemireCFGrossTSGuilletteLJJr.Reproductive impairment in the Florida panther: nature or nurture? Environ Health Perspect (1995) 103(Suppl 4):7986. doi: 10.1289/ehp.103-1519283

  • 18

    MengXde RooijDGWesterdahlKSaarmaMSariolaH. Promotion of seminomatous tumors by targeted overexpression of glial cell line-derived neurotrophic factor in mouse testis. Cancer Res (2001) 61(8):3267–71.

  • 19

    PalmerJRHerbstALNollerKLBoggsDATroisiRTitus-ErnstoffLet al. Urogenital abnormalities in men exposed to diethylstilbestrol in utero: a cohort study. Environ Health Global Access Sci Source (2009) 8:37. doi: 10.1186/1476-069X-8-37

  • 20

    FenichelPBrucker-DavisFChevalierN. The history of Distilbene(R) (Diethylstilbestrol) told to grandchildren–the transgenerational effect. Annal D’endocrinol (2015) 76(3):253–9. doi: 10.1016/j.ando.2015.03.008

  • 21

    StrohsnitterWCNollerKLHooverRNRobboySJPalmerJRTitus-ErnstoffLet al. Cancer risk in men exposed in utero to diethylstilbestrol. J Natl Cancer Institute (2001) 93(7):545–51. doi: 10.1093/jnci/93.7.545

  • 22

    MartinOVShialisTLesterJNScrimshawMDBoobisARVoulvoulisN. Testicular dysgenesis syndrome and the estrogen hypothesis: a quantitative meta-analysis. Environ Health Perspect (2008) 116(2):149–57. doi: 10.1289/ehp.10545

  • 23

    RyderSJCrawfordPIPethybridgeRJ. Is testicular cancer an occupational disease? A case-control study of Royal Naval personnel. J R Naval Med Service (1997) 83(3):130–46.

  • 24

    HardellLMalmqvistNOhlsonCGWestbergHErikssonM. Testicular cancer and occupational exposure to polyvinyl chloride plastics: a case-control study. Int J Cancer (2004) 109(3):425–9. doi: 10.1002/ijc.11709

  • 25

    KnightJAMarrettLDWeirHK. Occupation and risk of germ cell testicular cancer by histologic type in Ontario. J Occup Environ Med (1996) 38(9):884–90. doi: 10.1097/00043764-199609000-00010

  • 26

    GiannandreaFPaoliDFiga-TalamancaILombardoFLenziAGandiniL. Effect of endogenous and exogenous hormones on testicular cancer: the epidemiological evidence. Int J Dev Biol (2013) 57(2-4):255–63. doi: 10.1387/ijdb.130015fg

  • 27

    HardellLvan BavelBLindstromGCarlbergMDreifaldtACWijkstromHet al. Increased concentrations of polychlorinated biphenyls, hexachlorobenzene, and chlordanes in mothers of men with testicular cancer. Environ Health Perspect (2003) 111(7):930–4. doi: 10.1289/ehp.5816

  • 28

    PurdueMPEngelLSLangsethHNeedhamLLAndersenABarrDBet al. Prediagnostic serum concentrations of organochlorine compounds and risk of testicular germ cell tumors. Environ Health Perspect (2009) 117(10):1514–9. doi: 10.1289/ehp.0800359

  • 29

    McGlynnKAQuraishiSMGraubardBIWeberJPRubertoneMVEricksonRL. Persistent organochlorine pesticides and risk of testicular germ cell tumors. J Natl Cancer Institute (2008) 100(9):663–71. doi: 10.1093/jnci/djn101

  • 30

    BondeJPFlachsEMRimborgSGlazerCHGiwercmanARamlau-HansenCHet al. The epidemiologic evidence linking prenatal and postnatal exposure to endocrine disrupting chemicals with male reproductive disorders: a systematic review and meta-analysis. Hum Reprod Update (2016) 23(1):104–25. doi: 10.1093/humupd/dmw036

  • 31

    CohnBACirilloPMChristiansonRE. Prenatal DDT exposure and testicular cancer: a nested case-control study. Arch Environ Occup Health (2010) 65(3):127–34. doi: 10.1080/19338241003730887

  • 32

    CarreauSBourguibaSLambardSGaleraud-DenisIGenisselCLevalletJ. Reproductive system: aromatase and estrogens. Mol Cell Endocrinol (2002) 193(1-2):137–43. doi: 10.1016/S0303-7207(02)00107-7

  • 33

    HessRA. Estrogen in the adult male reproductive tract: a review. Reprod Biol Endocrinol RB&E (2003) 1:52. doi: 10.1186/1477-7827-1-52

  • 34

    CarreauSBouraima-LelongHDelalandeC. Role of estrogens in spermatogenesis. Front Biosci (2012) 4:111. doi: 10.2741/e356

  • 35

    CarreauSHessRA. Oestrogens and spermatogenesis. Philos Trans R Soc London Ser B Biol Sci (1546) 2010) 365:1517–35. doi: 10.1098/rstb.2009.0235

  • 36

    BoukariKCiampiMLGuiochon-MantelAYoungJLombesMMeduriG. Human fetal testis: source of estrogen and target of estrogen action. Hum Reprod (2007) 22(7):1885–92. doi: 10.1093/humrep/dem091

  • 37

    BerenszteinEBBaquedanoMSGonzalezCRSaracoNIRodriguezJPonzioRet al. Expression of aromatase, estrogen receptor alpha and beta, androgen receptor, and cytochrome P-450scc in the human early prepubertal testis. Pediatr Res (2006) 60(6):740–4. doi: 10.1203/01.pdr.0000246072.04663.bb

  • 38

    MakinenSMakelaSWeihuaZWarnerMRosenlundBSalmiSet al. Localization of oestrogen receptors alpha and beta in human testis. Mol Hum Reprod (2001) 7(6):497503. doi: 10.1093/molehr/7.6.497

  • 39

    CavacoJELaurentinoSSBarrosASousaMSocorroS. Estrogen receptors alpha and beta in human testis: both isoforms are expressed. Syst Biol Reprod Med (2009) 55(4):137–44. doi: 10.3109/19396360902855733

  • 40

    SaundersPTMillarMRMacphersonSIrvineDSGroomeNPEvansLRet al. ERbeta1 and the ERbeta2 splice variant (ERbetacx/beta2) are expressed in distinct cell populations in the adult human testis. J Clin Endocrinol Metab (2002) 87(6):2706–15. doi: 10.1210/jcem.87.6.8619

  • 41

    LambardSGaleraud-DenisISaundersPTCarreauS. Human immature germ cells and ejaculated spermatozoa contain aromatase and oestrogen receptors. J Mol Endocrinol (2004) 32(1):279–89. doi: 10.1677/jme.0.0320279

  • 42

    SmithEPBoydJFrankGRTakahashiHCohenRMSpeckerBet al. Estrogen resistance caused by a mutation in the estrogen-receptor gene in a man. New Engl J Med (1994) 331(16):1056–61. doi: 10.1056/NEJM199410203311604

  • 43

    RevankarCMCiminoDFSklarLAArterburnJBProssnitzER. A transmembrane intracellular estrogen receptor mediates rapid cell signaling. Science (2005) 307(5715):1625–30. doi: 10.1126/science.1106943

  • 44

    JacenikDCygankiewiczAIKrajewskaWM. The G protein-coupled estrogen receptor as a modulator of neoplastic transformation. Mol Cell Endocrinol (2016) 429:10–8. doi: 10.1016/j.mce.2016.04.011

  • 45

    XuSYuSDongDLeeLTO. G Protein-Coupled Estrogen Receptor: A Potential Therapeutic Target in Cancer. Front Endocrinol (2019) 10:725:725. doi: 10.3389/fendo.2019.00725

  • 46

    TaoSHeHChenQYueW. GPER mediated estradiol reduces miR-148a to promote HLA-G expression in breast cancer. Biochem Biophys Res Commun (2014) 451(1):74–8. doi: 10.1016/j.bbrc.2014.07.073

  • 47

    TengYRaddeBNLitchfieldLMIvanovaMMProughRAClarkBJet al. Dehydroepiandrosterone Activation of G-protein-coupled Estrogen Receptor Rapidly Stimulates MicroRNA-21 Transcription in Human Hepatocellular Carcinoma Cells. J Biol Chem (2015) 290(25):15799–811. doi: 10.1074/jbc.M115.641167

  • 48

    VivacquaADe MarcoPSantollaMFCirilloFPellegrinoMPannoMLet al. Estrogenic gper signaling regulates mir144 expression in cancer cells and cancer-associated fibroblasts (cafs). Oncotarget (2015) 6(18):16573–87. doi: 10.18632/oncotarget.4117

  • 49

    FilardoEJQuinnJABlandKIFrackeltonARJr.Estrogen-induced activation of Erk-1 and Erk-2 requires the G protein-coupled receptor homolog, GPR30, and occurs via trans-activation of the epidermal growth factor receptor through release of HB-EGF. Mol Endocrinol (2000) 14(10):1649–60. doi: 10.1210/mend.14.10.0532

  • 50

    FilardoEJ. Epidermal growth factor receptor (EGFR) transactivation by estrogen via the G-protein-coupled receptor, GPR30: a novel signaling pathway with potential significance for breast cancer. J Steroid Biochem Mol Biol (2002) 80(2):231–8. doi: 10.1016/s0960-0760(01)00190-x

  • 51

    RecchiaAGDe FrancescoEMVivacquaASisciDPannoMLAndoSet al. The G protein-coupled receptor 30 is up-regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) in breast cancer cells and cardiomyocytes. J Biol Chem (2011) 286(12):10773–82. doi: 10.1074/jbc.M110.172247

  • 52

    De FrancescoEMLappanoRSantollaMFMarsicoSCarusoAMaggioliniM. HIF-1alpha/GPER signaling mediates the expression of VEGF induced by hypoxia in breast cancer associated fibroblasts (CAFs). Breast Cancer Res (2013) 15(4):R64. doi: 10.1186/bcr3458

  • 53

    De MarcoPBartellaVVivacquaALappanoRSantollaMFMorcavalloAet al. Insulin-like growth factor-I regulates GPER expression and function in cancer cells. Oncogene (2013) 32(6):678–88. doi: 10.1038/onc.2012.97

  • 54

    AvinoSDe MarcoPCirilloFSantollaMFDe FrancescoEMPerriMGet al. Stimulatory actions of IGF-I are mediated by IGF-IR cross-talk with GPER and DDR1 in mesothelioma and lung cancer cells. Oncotarget (2016) 7(33):52710–28. doi: 10.18632/oncotarget.10348

  • 55

    OkamotoMMizukamiY. GPER negatively regulates TNFalpha-induced IL-6 production in human breast cancer cells via NF-kappaB pathway. Endocr J (2016) 63(5):485–93. doi: 10.1507/endocrj.EJ15-0571

  • 56

    ZhuPLiaoLYZhaoTTMoXMChenGGLiuZM. GPER/ERK&AKT/NF-kappaB pathway is involved in cadmium-induced proliferation, invasion and migration of GPER-positive thyroid cancer cells. Mol Cell Endocrinol (2017) 442:6880. doi: 10.1016/j.mce.2016.12.007

  • 57

    FeldmanRDDingQHussainYLimbirdLEPickeringJGGrosR. Aldosterone mediates metastatic spread of renal cancer via the G protein-coupled estrogen receptor (GPER). FASEB J (2016) 30(6):2086–96. doi: 10.1096/fj.15-275552

  • 58

    RigiraccioloDCScarpelliALappanoRPisanoASantollaMFAvinoSet al. GPER is involved in the stimulatory effects of aldosterone in breast cancer cells and breast tumor-derived endothelial cells. Oncotarget (2016) 7(1):94111. doi: 10.18632/oncotarget.6475

  • 59

    ParkerBMWertzSLPollardCMDesimineVLManingJMcCrinkKAet al. Novel Insights into the Crosstalk between Mineralocorticoid Receptor and G Protein-Coupled Receptors in Heart Adverse Remodeling and Disease. Int J Mol Sci (2018) 19(12):3764. doi: 10.3390/ijms19123764

  • 60

    ChevalierNVegaABouskineASiddeekBMichielsJFChevallierDet al. GPR30, the non-classical membrane G protein related estrogen receptor, is overexpressed in human seminoma and promotes seminoma cell proliferation. PloS One (2012) 7(4):e34672. doi: 10.1371/journal.pone.0034672

  • 61

    RagoVGiordanoFBrunelliEZitoDAquilaSCarpinoA. Identification of G protein-coupled estrogen receptor in human and pig spermatozoa. J Anat (2014) 224(6):732–6. doi: 10.1111/joa.12183

  • 62

    FenichelPChevalierN. Is Testicular Germ Cell Cancer Estrogen Dependent? The Role of Endocrine Disrupting Chemicals. Endocrinology (2019) 160(12):2981–9. doi: 10.1210/en.2019-00486

  • 63

    FilardoEJGraeberCTQuinnJAResnickMBGiriDDeLellisRAet al. Distribution of GPR30, a seven membrane-spanning estrogen receptor, in primary breast cancer and its association with clinicopathologic determinants of tumor progression. Clin Cancer Res (2006) 12(21):6359–66. doi: 10.1158/1078-0432.CCR-06-0860

  • 64

    SmithHOArias-PulidoHKuoDYHowardTQuallsCRLeeSJet al. GPR30 predicts poor survival for ovarian cancer. Gynecol Oncol (2009) 114(3):465–71. doi: 10.1016/j.ygyno.2009.05.015

  • 65

    ProssnitzERArterburnJBSmithHOOpreaTISklarLAHathawayHJ. Estrogen signaling through the transmembrane G protein-coupled receptor GPR30. Annu Rev Physiol (2008) 70:165–90. doi: 10.1146/annurev.physiol.70.113006.100518

  • 66

    RogerCLambardSBouskineAMograbiBChevallierDNeboutMet al. Estrogen-induced growth inhibition of human seminoma cells expressing estrogen receptor beta and aromatase. J Mol Endocrinol (2005) 35(1):191–9. doi: 10.1677/jme.1.01704

  • 67

    BouskineANeboutMMograbiBBrucker-DavisFRogerCFenichelP. Estrogens promote human testicular germ cell cancer through a membrane-mediated activation of extracellular regulated kinase and protein kinase A. Endocrinology (2008) 149(2):565–73. doi: 10.1210/en.2007-1318

  • 68

    FrancoRBosciaFGigantinoVMarraLEspositoFFerraraDet al. GPR30 is overexpressed in post-puberal testicular germ cell tumors. Cancer Biol Ther (2011) 11(6):609–13. doi: 10.4161/cbt.11.6.14672

  • 69

    BosciaFPassaroCGigantinoVPerdonaSFrancoRPortellaGet al. High levels of GPR30 protein in human testicular carcinoma in situ and seminomas correlate with low levels of estrogen receptor-beta and indicate a switch in estrogen responsiveness. J Cell Physiol (2015) 230(6):1290–7. doi: 10.1002/jcp.24864

  • 70

    RagoVRomeoFGiordanoFMaggioliniMCarpinoA. Identification of the estrogen receptor GPER in neoplastic and non-neoplastic human testes. Reprod Biol Endocrinol RB&E (2011) 9:135. doi: 10.1186/1477-7827-9-135

  • 71

    ChevalierNBouskineAFenichelP. Bisphenol A promotes testicular seminoma cell proliferation through GPER/GPR30. Int J Cancer (2012) 130(1):241–2. doi: 10.1002/ijc.25972

  • 72

    PaisVLeavILauKMJiangZHoSM. Estrogen receptor-beta expression in human testicular germ cell tumors. Clin Cancer Res (2003) 9(12):4475–82.

  • 73

    FerlinAGanzFPengoMSeliceRFrigoACForestaC. Association of testicular germ cell tumor with polymorphisms in estrogen receptor and steroid metabolism genes. Endocrine-Related Cancer (2010) 17(1):1725. doi: 10.1677/ERC-09-0176

  • 74

    BrokkenLJLundberg-GiwercmanYRajpert De-MeytsEEberhardJStahlOCohn-CedermarkGet al. Association of polymorphisms in genes encoding hormone receptors ESR1, ESR2 and LHCGR with the risk and clinical features of testicular germ cell cancer. Mol Cell Endocrinol (2012) 351(2):279–85. doi: 10.1016/j.mce.2011.12.018

  • 75

    ChevalierNPaul-BellonRCamparoPMichielsJFChevallierDFenichelP. Genetic variants of GPER/GPR30, a novel estrogen-related G protein receptor, are associated with human seminoma. Int J Mol Sci (2014) 15(1):1574–89. doi: 10.3390/ijms15011574

  • 76

    ZamaAMUzumcuM. Fetal and neonatal exposure to the endocrine disruptor methoxychlor causes epigenetic alterations in adult ovarian genes. Endocrinology (2009) 150(10):4681–91. doi: 10.1210/en.2009-0499

  • 77

    AnwayMDCuppASUzumcuMSkinnerMK. Epigenetic transgenerational actions of endocrine disruptors and male fertility. Science (2005) 308(5727):1466–9. doi: 10.1126/science.1108190

  • 78

    DumasiaKKumarADeshpandeSBalasinorNH. Estrogen signaling, through estrogen receptor beta, regulates DNA methylation and its machinery in male germ line in adult rats. Epigenetics (2017) 12(6):476–83. doi: 10.1080/15592294.2017.1309489

  • 79

    MarkulinDVojtaASamarzijaIGamulinMBeceheliIJukicIet al. Association Between RASSF1A Promoter Methylation and Testicular Germ Cell Tumor: A Meta-analysis and a Cohort Study. Cancer Genomics Proteomics (2017) 14(5):363–72. doi: 10.21873/cgp.20046

  • 80

    KillianJKDorssersLCTrabertBGillisAJCookMBWangYet al. Imprints and DPPA3 are bypassed during pluripotency- and differentiation-coupled methylation reprogramming in testicular germ cell tumors. Genome Res (2016) 26(11):1490–504. doi: 10.1101/gr.201293.115

  • 81

    VoorhoevePMle SageCSchrierMGillisAJStoopHNagelRet al. A genetic screen implicates miRNA-372 and miRNA-373 as oncogenes in testicular germ cell tumors. Cell (2006) 124(6):1169–81. doi: 10.1016/j.cell.2006.02.037

  • 82

    LoboJGillisAJMJeronimoCHenriqueRLooijengaLHJ. Human Germ Cell Tumors are Developmental Cancers: Impact of Epigenetics on Pathobiology and Clinic. Int J Mol Sci (2019) 20(2):258. doi: 10.3390/ijms20020258

  • 83

    AlmstrupKNielsenJEMlynarskaOJansenMTJorgensenASkakkebaekNEet al. Carcinoma in situ testis displays permissive chromatin modifications similar to immature foetal germ cells. Br J Cancer (2010) 103(8):1269–76. doi: 10.1038/sj.bjc.6605880

  • 84

    BouskineAVegaANeboutMBenahmedMFenichelP. Expression of embryonic stem cell markers in cultured JKT-1, a cell line derived from a human seminoma. Int J Androl (2010) 33(1):5463. doi: 10.1111/j.1365-2605.2009.00950.x

  • 85

    BouskineANeboutMBrucker-DavisFBenahmedMFenichelP. Low doses of bisphenol A promote human seminoma cell proliferation by activating PKA and PKG via a membrane G-protein-coupled estrogen receptor. Environ Health Perspect (2009) 117(7):1053–8. doi: 10.1289/ehp.0800367

  • 86

    ChevalierNFenichelP. Endocrine disruptors: new players in the pathophysiology of type 2 diabetes? Diabetes Metab (2015) 41(2):107–15. doi: 10.1016/j.diabet.2014.09.005

  • 87

    FenichelPDechauxHHartheCGalJFerrariPPaciniPet al. Unconjugated bisphenol A cord blood levels in boys with descended or undescended testes. Hum Reprod (2012) 27(4):983–90. doi: 10.1093/humrep/der451

  • 88

    VandenbergLNMaffiniMVSonnenscheinCRubinBSSotoAM. Bisphenol-A and the great divide: a review of controversies in the field of endocrine disruption. Endocrine Rev (2009) 30(1):7595. doi: 10.1210/er.2008-0021

  • 89

    FenichelPChevalierNBrucker-DavisF. Bisphenol A: an endocrine and metabolic disruptor. Annal D’endocrinol (2013) 74(3):211–20. doi: 10.1016/j.ando.2013.04.002

  • 90

    PupoMPisanoALappanoRSantollaMFDe FrancescoEMAbonanteSet al. Bisphenol A induces gene expression changes and proliferative effects through GPER in breast cancer cells and cancer-associated fibroblasts. Environ Health Perspect (2012) 120(8):1177–82. doi: 10.1289/ehp.1104526

  • 91

    VandenbergLN. Non-monotonic dose responses in studies of endocrine disrupting chemicals: bisphenol a as a case study. Dose Response (2014) 12(2):259–76. doi: 10.2203/dose-response.13-020.Vandenberg

  • 92

    ChevalierNPaul-BellonRFenichelP. Comment on “Effects of Atrazine on Estrogen Receptor alpha- and G Protein-Coupled Receptor 30-Mediated Signaling and Proliferation in Cancer Cells and Cancer-Associated Fibroblasts”. Environ Health Perspect (2016) 124(4):A64–5. doi: 10.1289/ehp.1510927

  • 93

    AjjHChesnelAPinelSPlenatFFlamentSDumondH. An alkylphenol mix promotes seminoma derived cell proliferation through an ERalpha36-mediated mechanism. PloS One (2013) 8(4):e61758. doi: 10.1371/journal.pone.0061758

  • 94

    WangZZhangXShenPLoggieBWChangYDeuelTF. Identification, cloning, and expression of human estrogen receptor-alpha36, a novel variant of human estrogen receptor-alpha66. Biochem Biophys Res Commun (2005) 336(4):1023–7. doi: 10.1016/j.bbrc.2005.08.226

  • 95

    WallacidesAChesnelAAjjHChilletMFlamentSDumondH. Estrogens promote proliferation of the seminoma-like TCam-2 cell line through a GPER-dependent ERalpha36 induction. Mol Cell Endocrinol (2012) 350(1):6171. doi: 10.1016/j.mce.2011.11.021

  • 96

    ChimentoADe LucaANocitoMCAvenaPLa PadulaDZavagliaLet al. Role of GPER-Mediated Signaling in Testicular Functions and Tumorigenesis. Cells (2020) 9(9):2115. doi: 10.3390/cells9092115

  • 97

    FilardoEJ. A role for G-protein coupled estrogen receptor (GPER) in estrogen-induced carcinogenesis: Dysregulated glandular homeostasis, survival and metastasis. J Steroid Biochem Mol Biol (2018) 176:3848. doi: 10.1016/j.jsbmb.2017.05.005

  • 98

    De FrancescoEMMaggioliniMMustiAM. Crosstalk between Notch, HIF-1alpha and GPER in Breast Cancer EMT. Int J Mol Sci (2018) 19(7):2011. doi: 10.3390/ijms19072011

  • 99

    De FrancescoEMSimsAHMaggioliniMSotgiaFLisantiMPClarkeRB. GPER mediates the angiocrine actions induced by IGF1 through the HIF-1alpha/VEGF pathway in the breast tumor microenvironment. Breast Cancer Res (2017) 19(1):129. doi: 10.1186/s13058-017-0923-5

  • 100

    RiceACortesELachowskiDOertlePMatellanCThorpeSDet al. GPER Activation Inhibits Cancer Cell Mechanotransduction and Basement Membrane Invasion via RhoA. Cancers (Basel) (2020) 12(2):289. doi: 10.3390/cancers12020289

  • 101

    ChieffiP. An up-date on novel molecular targets in testicular germ cell tumors subtypes. Intractable Rare Dis Res (2019) 8(2):161–4. doi: 10.5582/irdr.2019.01055

  • 102

    ProssnitzERArterburnJB. International Union of Basic and Clinical Pharmacology. XCVII. G Protein-Coupled Estrogen Receptor and Its Pharmacologic Modulators. Pharmacol Rev (2015) 67(3):505–40. doi: 10.1124/pr.114.009712

  • 103

    Zacarias-LaraOJMendez-LunaDMartinez-RuizGGarcia-SanchezJRFragoso-VazquezMJBelloMet al. Synthesis and In Vitro Evaluation of Tetrahydroquinoline Derivatives as Antiproliferative Compounds of Breast Cancer via Targeting the GPER. Anticancer Agents Med Chem (2019) 19(6):760–71. doi: 10.2174/1871520618666181119094144

  • 104

    DeLeonCWangHHGunnJWilhelmMColeAArnettSet al. A novel GPER antagonist protects against the formation of estrogen-induced cholesterol gallstones in female mice. J Lipid Res (2020) 61(5):767–77. doi: 10.1194/jlr.RA119000592

  • 105

    LiuCLiaoYFanSFuXXiongJZhouSet al. G-Protein-Coupled Estrogen Receptor Antagonist G15 Decreases Estrogen-Induced Development of Non-Small Cell Lung Cancer. Oncol Res (2019) 27(3):283–92. doi: 10.3727/096504017X15035795904677

  • 106

    LiuCLiaoYFanSTangHJiangZZhouBet al. G protein-coupled estrogen receptor (GPER) mediates NSCLC progression induced by 17beta-estradiol (E2) and selective agonist G1. Med Oncol (2015) 32(4):104. doi: 10.1007/s12032-015-0558-2

  • 107

    De FrancescoEMPellegrinoMSantollaMFLappanoRRicchioEAbonanteSet al. GPER mediates activation of HIF1alpha/VEGF signaling by estrogens. Cancer Res (2014) 74(15):4053–64. doi: 10.1158/0008-5472.CAN-13-3590

  • 108

    SantollaMFAvinoSPellegrinoMDe FrancescoEMDe MarcoPLappanoRet al. SIRT1 is involved in oncogenic signaling mediated by GPER in breast cancer. Cell Death Dis (2015) 6:e1834. doi: 10.1038/cddis.2015.201

  • 109

    NataleCALiJPitarresiJRNorgardRJDentchevTCapellBCet al. Pharmacologic Activation of the G Protein-Coupled Estrogen Receptor Inhibits Pancreatic Ductal Adenocarcinoma. Cell Mol Gastroenterol Hepatol (2020). 10(4):868–80.e1. doi: 10.1016/j.jcmgh.2020.04.016

  • 110

    ChimentoASirianniRCasaburiIZoleaFRizzaPAvenaPet al. GPER agonist G-1 decreases adrenocortical carcinoma (ACC) cell growth in vitro and in vivo. Oncotarget (2015) 6(22):19190–203. doi: 10.18632/oncotarget.4241

  • 111

    CasaburiIAvenaPDe LucaASirianniRRagoVChimentoAet al. GPER-independent inhibition of adrenocortical cancer growth by G-1 involves ROS/Egr-1/BAX pathway. Oncotarget (2017) 8(70):115609–19. doi: 10.18632/oncotarget.23314

  • 112

    De FrancescoEMRoccaCScavelloFAmelioDPasquaTRigiraccioloDCet al. Protective Role of GPER Agonist G-1 on Cardiotoxicity Induced by Doxorubicin. J Cell Physiol (2017) 232(7):1640–9. doi: 10.1002/jcp.25585

  • 113

    da SilvaJSSunXAhmadSWangHSudoRTVaragicJet al. G-Protein-Coupled Estrogen Receptor Agonist G1 Improves Diastolic Function and Attenuates Cardiac Renin-Angiotensin System Activation in Estrogen-Deficient Hypertensive Rats. J Cardiovasc Pharmacol (2019) 74(5):443–52. doi: 10.1097/FJC.0000000000000721

  • 114

    BartonMMeyerMRProssnitzER. Nox1 downregulators: A new class of therapeutics. Steroids (2019) 152:108494. doi: 10.1016/j.steroids.2019.108494

  • 115

    TutzauerJSjostromMBendahlPORydenLFernoMLeeb-LundbergLMFet al. Plasma membrane expression of G protein-coupled estrogen receptor (GPER)/G protein-coupled receptor 30 (GPR30) is associated with worse outcome in metachronous contralateral breast cancer. PloS One (2020) 15(4):e0231786. doi: 10.1371/journal.pone.0231786

  • 116

    SjostromMHartmanLGrabauDFornanderTMalmstromPNordenskjoldBet al. Lack of G protein-coupled estrogen receptor (GPER) in the plasma membrane is associated with excellent long-term prognosis in breast cancer. Breast Cancer Res Treat (2014) 145(1):6171. doi: 10.1007/s10549-014-2936-4

  • 117

    IgnatovAIgnatovTWeissenbornCEggemannHBischoffJSemczukAet al. G-protein-coupled estrogen receptor GPR30 and tamoxifen resistance in breast cancer. Breast Cancer Res Treat (2011) 128(2):457–66. doi: 10.1007/s10549-011-1584-1

Summary

Keywords

testicular germ cell cancer, estrogen receptors, GPR30/GPER, endocrine disrupting compounds, fetal exposure, bisphenol A

Citation

Chevalier N, Hinault C, Clavel S, Paul-Bellon R and Fenichel P (2021) GPER and Testicular Germ Cell Cancer. Front. Endocrinol. 11:600404. doi: 10.3389/fendo.2020.600404

Received

29 August 2020

Accepted

07 December 2020

Published

26 January 2021

Volume

11 - 2020

Edited by

Marilena Kampa, University of Crete, Greece

Reviewed by

Ernestina Marianna De Francesco, University of Catania, Italy; Rosamaria Lappano, University of Calabria, Italy

Updates

Copyright

*Correspondence: Nicolas Chevalier, ;

This article was submitted to Molecular and Structural Endocrinology, a section of the journal Frontiers in Endocrinology

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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