Human myometrium and leiomyomas express gonadotropin-releasing hormone 2 and gonadotropin-releasing hormone 2 receptor

Role of gonadotropin-releasing hormone 2 and its receptor in human reproductive cancers

Gonadotropin-releasing hormone (GnRH1) and its receptor (GnRHR1) drive reproduction by regulating gonadotropins. Another form, GnRH2, and its receptor (GnRHR2), also exist in mammals. In humans, GnRH2 and GnRHR2 genes are present, but coding errors in the GnRHR2 gene are predicted to hinder full-length protein production. Nonetheless, mounting evidence supports the presence of a functional GnRHR2 in humans. GnRH2 and its receptor have been identified throughout the body, including peripheral reproductive tissues like the ovary, uterus, breast, and prostate. In addition, GnRH2 and its receptor have been detected in a wide number of reproductive cancer cells in humans. Notably, GnRH2 analogues have potent anti-proliferative, pro-apoptotic, and/or anti-metastatic effects on various reproductive cancers, including endometrial, breast, placental, ovarian, and prostate. Thus, GnRH2 is an emerging target to treat human reproductive cancers.

GnRH agonists and antagonists in therapy of symptomatic uterine fibroids - current roles and future perspectives

INTRODUCTION

Uterine fibroids are the most common noncancerous tumors in women of childbearing age. This review was developed to evaluate the current role of gonadotropin-releasing hormone (GnRH) agonists and antagonists in the therapy of symptomatic uterine fibroids.

AREAS COVERED

There is a great need for alternative methods for surgical treatment of uterine fibroids. Hormonal therapy remains the first-line treatment option for most patients. GnRH analogs (agonists and antagonists) modulate the pulsatile release of GnRH. This review summarizes the available literature concerning pharmacologic principles underlying the mechanism of action of GnRH and its analogs, as well as individual therapeutic applications to which these drugs have been applied.

EXPERT OPINION

In many cases, it is possible to try to treat uterine fibroids pharmacologically. Both groups of GnRH analogs are used in therapy, agonists instead as a preparation for surgery, and antagonists as a drug for long-term use. It is essential to develop this path further and look for at least long-term-release systems or new methods of administering these drugs. It is also important from the patient's perspective to search for possible drugs that may have an additive effect of decreasing side effects when combined with GnRH analogs.

Relugolix and elagolix directly inhibit leiomyoma extracellular matrix production in 2-dimesnional and 3-dimensional cell cultures

OBJECTIVE

To determine the effect relugolix and elagolix have on the production of extracellular matrix (ECM) proteins in human leiomyoma cells.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S) OR ANIMALS

None. January 5, 2022 Cell culture, protein analysis, immunohistochemistry.

MAIN OUTCOME MEASURE(S)

Production of GnRHR, COL1A1, FN1, VCAN, p-ERK, & ERK in treated/untreated leiomyoma cells.

RESULTS

100 nM relugolix resulted in decreased production of COL1A1 at 24 (1.78 0.06-fold; P < .05) and 48 hours (1.92 0.14-fold; P < .05). Elagolix treatment resulted in a decrease in COL1A1 production at 24 but not 48 hours. In 2D and 3D, 100 nM relugolix resulted in decreased production of FN1 at 24 (1.7 ± 0.07-fold; P < .05) and 48 hours (1.8 ± 0.07-fold; P < .05); 100 nM elagolix resulted in decreased production of FN1 at 24 (1.7 ± 0.14-fold; P < .05) and 48 hours (2.0 ± 0.09-fold; P < .05). For cells treated with relugolix 100 nM resulted in decreased VCAN production by 48 hours (0.66 ± 0.07-fold; P < .05). Contrary to our 3D data, 2D elagolix-treated cells demonstrated a decrease in VCAN production that was identified only at 24 hours. For GnRHR, no significant difference between the drugs was seen at 24 hours; at 48 hours production was only significantly decreased for relugolix (P < .05). Comparing both drugs, there was a significant difference in the concentration of p-ERK to ERK at 24 hours (P < .05); there was no difference by 48 hours.

CONCLUSIONS

Our findings demonstrated that treatment with either drug can 1) decrease ECM protein production and 2) inhibit the MAPK pathway.

Deciphering the Role of Histone Modifications in Uterine Leiomyoma: Acetylation of H3K27 Regulates the Expression of Genes Involved in Proliferation, Cell Signaling, Cell Transport, Angiogenesis and Extracellular Matrix Formation

Uterine leiomyoma (UL) is a benign tumor arising from myometrium (MM) with a high prevalence and unclear pathology. Histone modifications are altered in tumors, particularly via histone acetylation which is correlated with gene activation. To identify if the acetylation of H3K27 is involved in UL pathogenesis and if its reversion may be a therapeutic option, we performed a prospective study integrating RNA-seq (n = 48) and CHIP-seq for H3K27ac (n = 19) in UL vs MM tissue, together with qRT-PCR of SAHA-treated UL cells (n = 10). CHIP-seq showed lower levels of H3K27ac in UL versus MM (p-value < 2.2 × 10−16). From 922 DEGs found in UL vs. MM (FDR < 0.01), 482 presented H3K27ac. A differential acetylation (FDR < 0.05) was discovered in 82 of these genes (29 hyperacetylated/upregulated, 53 hypoacetylated/downregulated). Hyperacetylation/upregulation of oncogenes (NDP,HOXA13,COL24A1,IGFL3) and hypoacetylation/downregulation of tumor suppressor genes (CD40,GIMAP8,IL15,GPX3,DPT) altered the immune system, the metabolism, TGFβ3 and the Wnt/β-catenin pathway. Functional enrichment analysis revealed deregulation of proliferation, cell signaling, transport, angiogenesis and extracellular matrix. Inhibition of histone deacetylases by SAHA increased expression of hypoacetylated/downregulated genes in UL cells (p < 0.05). Conclusively, H3K27ac regulates genes involved in UL onset and maintenance. Histone deacetylation reversion upregulates the expression of tumor suppressor genes in UL cells, suggesting targeting histone modifications as a therapeutic approach for UL.

5-aza-2'-deoxycitidine inhibits cell proliferation, extracellular matrix formation and Wnt/β-catenin pathway in human uterine leiomyomas

BACKGROUND

Uterine leiomyoma is a benign tumor with unclear pathogenesis and inaccurate treatment. This tumor exhibits altered DNA methylation related to disease progression. DNMT inhibitors as 5-aza-2'-deoxycytidine (5-aza-CdR), have been suggested to treat tumors in which DNA methylation is altered. We aimed to evaluate whether DNA methylation reversion with 5-aza-CdR reduces cell proliferation and extracellular matrix (ECM) formation in uterine leiomyoma cells to provide a potential treatment option.

METHODS

Prospective study using uterine leiomyoma and adjacent myometrium tissues and human uterine leiomyoma primary (HULP) cells (n = 16). In tissues, gene expression was analyzed by qRT-PCR and DNMT activity by ELISA. Effects of 5-aza-CdR treatment on HULP cells were assessed by CellTiter, western blot, and qRT-PCR.

RESULTS

DNMT1 gene expression was higher in uterine leiomyoma vs myometrium. Similarly, DNMT activity was greater in uterine leiomyoma and HULP cells (6.5 vs 3.8 OD/h/mg; 211.3 vs 63.7 OD/h/mg, respectively). After 5-aza-CdR treatment on HULP cells, cell viability was reduced, significantly so at 10 μM (85.3%). Treatment with 10 μM 5-aza-CdR on HULP cells significantly decreased expression of proliferation marker PCNA (FC = 0.695) and of ECM proteins (COLLAGEN I FC = 0.654; PAI-1, FC = 0.654; FIBRONECTIN FC = 0.733). 5-aza-CdR treatment also decreased expression of Wnt/β-catenin pathway final targets, including WISP1 protein expression (10 μM, FC = 0.699), c-MYC gene expression (2 μM, FC = 0.745 and 10 μM, FC = 0.728), and MMP7 gene expression (5 μM, FC = 0.520 and 10 μM, FC = 0.577).

CONCLUSIONS

5-aza-CdR treatment inhibits cell proliferation, ECM formation, and Wnt/β-catenin signaling pathway targets in HULP cells, suggesting that DNA methylation inhibition is a viable therapeutic target in uterine leiomyoma.

Gonadotropin-releasing hormone analogs: Mechanisms of action and clinical applications in female reproduction

Extra-hypothalamic GnRH and extra-pituitary GnRH receptors exist in multiple human reproductive tissues, including the ovary, endometrium and myometrium. Recently, new analogs (agonists and antagonists) and modes of GnRH have been developed for clinical application during controlled ovarian hyperstimulation for assisted reproductive technology (ART). Additionally, the analogs and upstream regulators of GnRH suppress gonadotropin secretion and regulate the functions of the reproductive axis. GnRH signaling is primarily involved in the direct control of female reproduction. The cellular mechanisms and action of the GnRH/GnRH receptor system have been clinically applied for the treatment of reproductive disorders and have widely been introduced in ART. New GnRH analogs, such as long-acting GnRH analogs and oral nonpeptide GnRH antagonists, are being continuously developed for clinical application. The identification of the upstream regulators of GnRH, such as kisspeptin and neurokinin B, provides promising potential to develop these upstream regulator-related analogs to control the hypothalamus-pituitary-ovarian axis.

Vitamin D as an effective treatment in human uterine leiomyomas independent of mediator complex subunit 12 mutation

OBJECTIVE

To study whether vitamin D (VitD) inhibits cell proliferation and Wnt/β-catenin and transforming growth factor-β (TGFβ) signaling pathways in uterine leiomyomas independent of mediator complex subunit 12 (MED12) mutation status.

DESIGN

Prospective study comparing leiomyoma vs. myometrial tissues and human uterine leiomyoma primary (HULP) cells treated with or without VitD and analyzed by MED12 mutation status.

SETTING

Hospital and university laboratories.

PATIENT(S)

Women with uterine leiomyoma without any treatment (n = 37).

INTERVENTION(S)

Uterine leiomyoma and myometrium samples were collected from women undergoing surgery because of symptomatic leiomyoma pathology.

MAIN OUTCOME MEASURE(S)

Analysis of Wnt/β-catenin and TGFβ pathways and proliferation by quantitative real-time polymerase chain reaction in leiomyoma and myometrial tissue as well as in VitD-treated HULP cells analyzed by Sanger sequencing.

RESULTS

Sequencing data showed that 46% of leiomyomas presented MED12 mutation, whereas no mutations were detected in adjacent myometrium. Expression of Wnt/β-catenin and TGFβ pathway genes was significantly increased in MED12-mutated leiomyomas compared to matched myometrium; no significant differences were found in wild-type (WT) leiomyomas. In HULP cells, VitD significantly decreased PCNA expression of both MED12-mutated and WT groups. VitD treatment decreased WNT4 and β-catenin expression in both groups compared to controls, with significance for WNT4 expression in MED12-mutated samples. Similarly, VitD significantly inhibited TGFβ3 expression in cells from both groups. MMP9 expression also decreased.

CONCLUSION

Despite molecular differences between MED12-mutated and WT leiomyomas, VitD inhibited Wnt/β-catenin and TGFβ pathways in HULP cells, suggesting VitD as an effective treatment to reduce proliferation and extracellular matrix formation in different molecular subtypes of uterine leiomyomas.

The effects of common variants in MDM2 and GNRH2 genes on the risk and survival of osteosarcoma in Han populations from Northwest China

Accumulating evidence has shown that both MDM2 and GNRH2 might be related to Osteosarcoma (OS) susceptibility. The study aimed to evaluate the effects of common variants in MDM2 and GNRH2 genes on the risk and survival of osteosarcoma in Han populations from Northwest China. In the study, we recruited 2292 subjects including 596 OS patients and 1696 healthy controls and genotyped 16 selected tag SNPs (6 from GNRH2 and 10 from MDM2). Genetic association analyses were performed at the genotypic and allelic levels. Survival curves were made for OS patients with different genotypes. Two SNPs, rs1690916 (MDM2, P = 0.0002) and rs3761243 (GNRH2, P = 0.0004), were identified to be significantly associated with OS risk. Moreover, SNP rs3761243 was strongly associated with pathological fracture (P = 2.61 × 10^–14), metastasis (P < 2.2 × 10^–16), and Enneking stage (P < 2.2 × 10^–16) in the OS group. Furthermore, survival curves based on different genotypes of SNP rs3761243 were found to be significantly different (P = 0.0003), suggesting increased risk with more copies of C alleles. Our results provide supportive evidence for genetic associations of MDM2 and GNRH2 genes with susceptibility to OS, and for the positive correlation of SNP rs3761243 in GNRH2 with the survival status of OS patients in Han populations from Northwest China.

Inhibition of tumor cell proliferation in human uterine leiomyomas by vitamin D via Wnt/β-catenin pathway

OBJECTIVE

To assess the effect of vitamin D (VitD) on human uterine leiomyomas through Wnt/β-catenin pathway inhibition, apoptosis induction, and cell growth arrest.

DESIGN

A prospective study comparing leiomyoma vs. myometrium tissues. Paired design study comparing human uterine leiomyoma primary (HULP) cells treated with or without VitD.

SETTING

University hospital.

PATIENT(S)

Human uterine leiomyoma and myometrium were collected from women (aged 35-52 years) without hormonal treatment.

INTERVENTION(S)

Samples were collected from women undergoing surgery due to symptomatic uterine leiomyoma pathology.

MAIN OUTCOME MEASURE(S)

Uterine leiomyoma and myometrium tissues were analyzed by western blot (WB) to determine proliferation, Wnt/β-catenin, and apoptosis pathways. HULP cells were used to study VitD effect in cell proliferation (WB), cell cycle (flow cytometry), Wnt/β-catenin and apoptosis genes (polymerase chain reaction arrays), Wnt-related proteins (protein array), and apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling [TUNEL] assay).

RESULTS

Human leiomyoma tissues compared with matched myometrium showed higher proliferation (fold change = 8.16; P=.0006) and altered Wnt/β-catenin pathway (fold change = 5.5; P<.0001), whereas no differences in apoptosis were observed. VitD induced cell growth arrest and decreased proliferation in HULP cells (fold change = 0.74; P=.007). Moreover, VitD decreased Wnt-pathway expression in HULP cells at gene (activity score = -0.775; P<.001) and protein levels. However, VitD did not induce apoptosis expression.

CONCLUSION

Increased proliferation and Wnt/β-catenin pathway deregulation play a role in the development and growth of leiomyomas, whereas apoptosis appears not to contribute. VitD exerts an antiproliferative action on HULP cells through cell growth arrest and Wnt/β-catenin pathway inhibition, but not through apoptosis regulation, suggesting VitD as an effective therapy to stabilize leiomyoma size and prevent its growth.

Expression and Role of Gonadotropin-Releasing Hormone 2 and Its Receptor in Mammals

Gonadotropin-releasing hormone 1 (GnRH1) and its receptor (GnRHR1) drive mammalian reproduction via regulation of the gonadotropins. Yet, a second form of GnRH (GnRH2) and its receptor (GnRHR2) also exist in mammals. GnRH2 has been completely conserved throughout 500 million years of evolution, signifying high selection pressure and a critical biological role. However, the GnRH2 gene is absent (e.g., rat) or inactivated (e.g., cow and sheep) in some species but retained in others (e.g., human, horse, and pig). Likewise, many species (e.g., human, chimpanzee, cow, and sheep) retain the GnRHR2 gene but lack the appropriate coding sequence to produce a full-length protein due to gene coding errors; although production of GnRHR2 in humans remains controversial. Certain mammals lack the GnRHR2 gene (e.g., mouse) or most exons entirely (e.g., rat). In contrast, old world monkeys, musk shrews, and pigs maintain the coding sequence required to produce a functional GnRHR2. Like GnRHR1, GnRHR2 is a 7-transmembrane, G protein-coupled receptor that interacts with G_αq/11 to mediate cell signaling. However, GnRHR2 retains a cytoplasmic tail and is only 40% homologous to GnRHR1. A role for GnRH2 and its receptor in mammals has been elusive, likely because common laboratory models lack both the ligand and receptor. Uniquely, both GnRH2 and GnRHR2 are ubiquitously expressed; transcript levels are abundant in peripheral tissues and scarcely found in regions of the brain associated with gonadotropin secretion, suggesting a divergent role from GnRH1/GnRHR1. Indeed, GnRH2 and its receptor are not physiological modulators of gonadotropin secretion in mammals. Instead, GnRH2 and GnRHR2 coordinate the interaction between nutritional status and sexual behavior in the female brain. Within peripheral tissues, GnRH2 and its receptor are novel regulators of reproductive organs. GnRH2 and GnRHR2 directly stimulate steroidogenesis within the porcine testis. In the female, GnRH2 and its receptor may help mediate placental function, implantation, and ovarian steroidogenesis. Furthermore, both the GnRH2 and GnRHR2 genes are expressed in human reproductive tumors and represent emerging targets for cancer treatment. Thus, GnRH2 and GnRHR2 have diverse functions in mammals which remain largely unexplored.

Gonadotropin-releasing hormone analogues inhibit leiomyoma extracellular matrix despite presence of gonadal hormones

OBJECTIVE

To determine the effect of GnRH analogues (GnRH-a) leuprolide acetate (LA) and cetrorelix acetate on gonadal hormone-regulated expression of extracellular matrix in uterine leiomyoma three-dimensional (3D) cultures.

DESIGN

Laboratory study.

SETTING

University research laboratory.

PATIENT(S)

Women undergoing hysterectomy for symptomatic leiomyomas.

INTERVENTION(S)

The 3D cell cultures, protein analysis, Western blot, immunohistochemistry.

MAIN OUTCOME MEASURE(S)

Expression of extracellular matrix proteins, collagen 1, fibronectin, and versican in leiomyoma cells 3D cultures exposed to E2, P, LA, cetrorelix acetate, and combinations for 24- and 72-hour time points.

RESULT(S)

The 3D leiomyoma cultures exposed to E2 for 24 hours demonstrated an increased expression of collagen-1 and fibronectin, which was maintained for up to 72 hours, a time point at which versican was up-regulated significantly. Although P up-regulated collagen-1 protein (1.29 ± 0.04) within 24 hours of exposure, significant increase in all extracellular matrix (ECM) proteins was observed when the gonadal hormones were used concomitantly. Significant decrease in the amount of ECM proteins was observed on use of GnRH-a, LA and cetrorelix, with 24-hour exposure. Both the compounds also significantly decreased ECM protein concentration despite the presence of E2 or both gonadal hormones.

CONCLUSION(S)

This study demonstrates that GnRH-a directly affect the gonadal hormone-regulated collagen-1, fibronectin, and versican production in their presence. These findings suggest that localized therapy with GnRH-a may inhibit leiomyoma growth even in the presence of endogenous gonadal hormone exposure, thereby providing a mechanism to eliminate the hypoestrogenic side effects associated with GnRH-a therapy.

Mechanical signaling in reproductive tissues: mechanisms and importance

The organs of the female reproductive system are among the most dynamic tissues in the human body, undergoing repeated cycles of growth and involution from puberty through menopause. To achieve such impressive plasticity, reproductive tissues must respond not only to soluble signals (hormones, growth factors, and cytokines) but also to physical cues (mechanical forces and osmotic stress) as well. Here, we review the mechanisms underlying the process of mechanotransduction-how signals are conveyed from the extracellular matrix that surrounds the cells of reproductive tissues to the downstream molecules and signaling pathways that coordinate the cellular adaptive response to external forces. Our objective was to examine how mechanical forces contribute significantly to physiological functions and pathogenesis in reproductive tissues. We highlight how widespread diseases of the reproductive tract, from preterm labor to tumors of the uterus and breast, result from an impairment in mechanical signaling.

The extracellular matrix contributes to mechanotransduction in uterine fibroids

The role of the extracellular matrix (ECM) and mechanotransduction as an important signaling factor in the human uterus is just beginning to be appreciated. The ECM is not only the substance that surrounds cells, but ECM stiffness will either compress cells or stretch them resulting in signals converted into chemical changes within the cell, depending on the amount of collagen, cross-linking, and hydration, as well as other ECM components. In this review we present evidence that the stiffness of fibroid tissue has a direct effect on the growth of the tumor through the induction of fibrosis. Fibrosis has two characteristics: (1) resistance to apoptosis leading to the persistence of cells and (2) secretion of collagen and other components of the ECM such a proteoglycans by those cells leading to abundant disposition of highly cross-linked, disoriented, and often widely dispersed collagen fibrils. Fibrosis affects cell growth by mechanotransduction, the dynamic signaling system whereby mechanical forces initiate chemical signaling in cells. Data indicate that the structurally disordered and abnormally formed ECM of uterine fibroids contributes to fibroid formation and growth. An appreciation of the critical role of ECM stiffness to fibroid growth may lead to new strategies for treatment of this common disease.

Comprehensive analysis of GnRH2 neuronal projections in zebrafish

The presence and conservation of GnRH2 across vertebrate species suggest important biological roles. However, the function of GnRH2 remains unclear. A good research model for GnRH2 functional studies is still lacking largely due to the absence of GnRH2 in the widely used mouse model. Hence, we used the zebrafish, for which powerful genetic tools are available, and developed a transgenic (Tg) line expressing enhanced green fluorescence protein (eGFP). The high sensitivity of eGFP, which can diffuse throughout the neuron, enables us to document the complete projectome of GnRH2 neurons at different developmental stages. Fine projection structures were observed without sacrificing the fish. Crossed with the GnRH3:tdTomato Tg line, the GnRH2:eGFP Tg line provides us with an opportunity to visualize the entire GnRH system simultaneously in one organism. This work will provide a framework to understand the function of the highly-conserved GnRH2 system.

Proceedings from the Third National Institutes of Health International Congress on Advances in Uterine Leiomyoma Research: comprehensive review, conference summary and future recommendations

BACKGROUND Uterine fibroids are the most common gynecologic tumors in women of reproductive age yet the etiology and pathogenesis of these lesions remain poorly understood. Age, African ancestry, nulliparity and obesity have been identified as predisposing factors for uterine fibroids. Symptomatic tumors can cause excessive uterine bleeding, bladder dysfunction and pelvic pain, as well as associated reproductive disorders such as infertility, miscarriage and other adverse pregnancy outcomes. Currently, there are limited noninvasive therapies for fibroids and no early intervention or prevention strategies are readily available. This review summarizes the advances in basic, applied and translational uterine fibroid research, in addition to current and proposed approaches to clinical management as presented at the 'Advances in Uterine Leiomyoma Research: 3rd NIH International Congress'. Congress recommendations and a review of the fibroid literature are also reported. METHODS This review is a report of meeting proceedings, the resulting recommendations and a literature review of the subject. RESULTS The research data presented highlights the complexity of uterine fibroids and the convergence of ethnicity, race, genetics, epigenetics and environmental factors, including lifestyle and possible socioeconomic parameters on disease manifestation. The data presented suggest it is likely that the majority of women with uterine fibroids will have normal pregnancy outcomes; however, additional research is warranted. As an alternative to surgery, an effective long-term medical treatment for uterine fibroids should reduce heavy uterine bleeding and fibroid/uterine volume without excessive side effects. This goal has not been achieved and current treatments reduce symptoms only temporarily; however, a multi-disciplined approach to understanding the molecular origins and pathogenesis of uterine fibroids, as presented in this report, makes our quest for identifying novel targets for noninvasive, possibly nonsystemic and effective long-term treatment very promising. CONCLUSIONS The Congress facilitated the exchange of scientific information among members of the uterine leiomyoma research and health-care communities. While advances in research have deepened our knowledge of the pathobiology of fibroids, their etiology still remains incompletely understood. Further needs exist for determination of risk factors and initiation of preventive measures for fibroids, in addition to continued development of new medical and minimally invasive options for treatment.

Reduction in the vascular bed volume of uterine fibroids after hormonal treatment: evaluation with dynamic double-echo R₂* imaging

PURPOSE

To demonstrate the reduction in vascular bed volume (VBV) of uterine fibroids after administration of gonadotropin-releasing hormone analogue (GnRHa) using magnetic resonance (MR) imaging including dynamic double-echo R₂* imaging (DDE-R₂*I) and to assess the value of DDE-R₂*I as a predictor of such reduction.

METHODS

Twenty-one women with uterine intramural fibroids underwent MR imaging including DDE-R₂*I before GnRHa treatment. DDE-R₂*I was acquired using a single-section, double-echo, fast spoiled gradient recalled acquisition in the steady state (SPGR) sequence. We calculated the area under the curve (AUC) of the signal intensity on R₂*I within a 3×3-cm²region of interest that served to represent the VBV. We repeated MR imaging after 2 administrations of GnRHa and repeated image analyses. We statistically analyzed correlations between (A) pre-treatment AUC (AUC(pre)) and AUC reduction and (B) AUC(pre) and volume reduction.

RESULTS

The interval between the 2 MR studies ranged from 56 to 119 days (mean: 80.4 days). The average volume of the fibroids before GnRHa treatment was 647.8 mL compared with 463.4 mL after the therapy (decreased by an average of 28.5%; P<0.0001). Meanwhile, measured AUC was reduced by 55.3% (483.4 vs. 206.5; P<0.0001). AUC(pre) correlated with volume reduction (r=0.68), but not AUC reduction.

CONCLUSIONS

We confirmed reduction in the VBV of fibroids using DDE-R₂*I. The measurement of AUC(pre) on DDE-R₂*I aids prediction of fibroid volume reduction but correlates poorly with the percentage of AUC reduction.

Gonadotropin-releasing hormone (GnRH) agonist leuprolide acetate and GnRH antagonist cetrorelix acetate directly inhibit leiomyoma extracellular matrix production

OBJECTIVE

To determine the direct effect that GnRH analogues leuprolide acetate and cetrorelix acetate have on extracellular matrix in human leiomyoma and patient-matched myometrial cells.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S)

None.

INTERVENTION(S)

Cell culture, proliferation studies, and messenger RNA and protein analysis.

MAIN OUTCOME MEASURE(S)

Expression of GnRHR1, COL1A1, fibronectin, and versican variant V0 in treated leiomyoma cells and patient-matched myometrial cells.

RESULT(S)

Leiomyoma cells were treated with GnRH analogues for 6, 24, and 120 hours. Leuprolide treatment for 6 hours resulted in an increase in expression of GnRHR1 (4.02 ± 0.12-fold), COL1A1 (6.41 ± 0.29-fold), fibronectin (9.69 ± 0.18-fold), and versican variant V0 (7.58 ± 0.43-fold). Leiomyoma cells treated with cetrorelix for 6 hours showed a decreased expression of GnRHR1 (0.5 ± 0.15-fold), COL1A1 (3.79 ± 0.7-fold), fibronectin (0.92 ± 0.09-fold), and versican variant V0 (0.14 ± 0.07-fold). Leuprolide treatment of leiomyoma cells at high concentrations (10(-5) M) did not result in an increase in protein production. Cetrorelix treatment of leiomyoma cells for 6 hours showed an increase in fibronectin protein production (3.14 ± 0.09-fold). Protein production of leiomyoma cells treated with cetrorelix for 120 hours demonstrated a decrease in GnRHR1 (0.51 ± 0.07-fold), COL1A1 (0.35 ± 0.07-fold), fibronectin (1.94 ± 0.08-fold), and versican variant V0 (0.77 ± 0.19-fold).

CONCLUSION(S)

Our findings demonstrate that GnRH analogue treatment directly regulated COL1A1, fibronectin, and matrix proteoglycan production. The reduction in versican variant V0 gene expression caused by cetrorelix treatment, and its association with the osmotic regulation of leiomyomas, presents a new and innovative approach to therapy for this disease.

Gonadotropin-releasing hormone agonist increases expression of osmotic response genes in leiomyoma cells

OBJECTIVE

To characterize hyperosmolarity-responsive genes in leiomyoma cells and determine whether gonadotropin-releasing hormone (GnRH) agonist treatment altered their expression.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S)

None.

INTERVENTION(S)

Cell culture under hypertonic conditions and with GnRH agonist treatment, RNA isolation, and real-time reverse-transcriptase polymerase chain reaction (RT-PCR).

MAIN OUTCOME MEASURE(S)

Expression of nuclear factor of activated T cells 5 (NFAT5), aldose reductase (AR), and sodium myo-inositol transporter 1 (SMIT) messenger RNA (mRNA) in immortalized leiomyoma and patient-matched myometrial cells.

RESULT(S)

Leiomyoma cells had increased basal expression of NFAT5 mRNA (1.7±0.08-fold) compared with myometrial cells. The NFAT5 increased further in leiomyoma cells cultured under hyperosmolar conditions (3.0±0.46-fold at 50 mM NaCl and 3.3±0.48-fold at 100 mM NaCl). The NFAT5-regulated mRNA transcripts for AR and SMIT were increased in untreated leiomyoma cells compared with myometrial cells and further increased in leiomyoma cells exposed to osmotic stress. The NFAT5 transcripts were decreased with low-dose GnRH agonist treatment but increased with supraphysiologic doses.

CONCLUSION(S)

Expression of hyperosmolarity genes was increased in leiomyoma cells relative to myometrial cells. Pharmacologic concentrations of GnRH agonist decreased NFAT5 expression, suggesting that water flows out of leiomyoma cells at pharmacologic doses.

G protein-coupled receptor expression in the adult and fetal adrenal glands

Hormonal regulation of adrenal function occurs primarily through G protein-coupled receptors (GPCR), which may play different roles in fetal vs. adult adrenal glands. In this study, we compared the transcript levels of GPCR between fetal and adult adrenal and found that gonadotropin-releasing hormone receptor (GnRHR), latrophilin 3 receptor, G protein-coupled receptor 37, angiotensin II receptor type 2, latrophilin 2 receptor and melanocortin receptor were expressed at significantly higher levels in fetal adrenal. High GnRHR protein expression was also detected in fetal adrenal using immunohistochemical analysis. To define potential ligand sources for fetal adrenal GnRHR, we demonstrated that GnRH1 mRNA was expressed at high levels in the placenta, while fetal adrenal had high expression of GnRH2. In summary, certain GPCR particularly GnRHR were highly expressed in fetal adrenal and the expression of GnRH mRNA in the placenta and the fetal adrenal raises the possibility of endocrine and/or paracrine/autocrine influences on fetal adrenal function. However, the exact function of GnRHR in fetal adrenal remains to be determined.

Retinoic acid treatment of human leiomyoma cells transformed the cell phenotype to one strongly resembling myometrial cells

BACKGROUND

Uterine leiomyomas are clinically significant tumours that may develop due to an altered differentiation pathway. We have previously identified a dysregulated retinoic acid (RA) pathway that reduced retinoic exposure in human leiomyoma surgical specimens, and have shown that the leiomyoma phenotype was characterized by excessive and disorganized extracellular matrix (ECM).

OBJECTIVE

The goal of this study was to determine the impact of RA exposure on the disrupted ECM phenotype of leiomyomas.

DESIGN AND METHODS

Study of immortalized and molecularly confirmed cells generated from surgical specimens of spontaneous uterine leiomyoma and matched myometrium.

RESULTS

Immortalized leiomyoma and myometrial cells retained the molecular characteristics of their progenitor tissue. Proliferation of leiomyoma cells was inhibited by all-trans retinoic acid (ATRA). Furthermore, there was a dose-dependent decrease in soluble extracellular collagen protein in ATRA-treated leiomyoma cells. Exposure of leiomyoma cells to ATRA resulted in a dose-dependent inhibition of templates for specific ECM protein production including collagen 1, collagen 4, fibronectin and versican. Notably, expression levels in treated leiomyoma cells approached those found in myometrial cells. These mRNA alterations translated into altered protein. Down-regulation was also observed among the RA pathway genes such as CYP26A1 with exposure to ATRA. Finally, ATRA down-regulated TGF-beta3 mRNA expression and the TGF-beta regulated genes in leiomyoma cells.

CONCLUSION

Exposure of leiomyomas to ATRA down-regulated cell proliferation, ECM formation, RA metabolism and TGF-beta regulation, suggesting that RA exposure can alter the leiomyoma phenotype to one that more closely approximates normal myometrium.