Novel method to characterize primary cultures of leiomyoma and myometrium with the use of confirmatory biomarker gene arrays

Pivotal Role of Ubiquitin Carboxyl-Terminal Hydrolase L1 (UCHL1) in Uterine Leiomyoma

Uterine leiomyomas are smooth-muscle tumors originating in the myometrium and are the most common pelvic tumors in women of reproductive age. Symptomatic tumors may result in abnormal uterine bleeding, bladder dysfunction, pelvic discomfort, and reproductive issues, such as infertility and miscarriage. There are currently few non-invasive treatments for leiomyoma, but there are no practical early intervention or preventive methods. In this study, human uterine leiomyoma and myometrial tissues were used to detect the protein and mRNA expression levels of UCHL1. To explore the effects of UCHL1 knockdown and inhibition in leiomyoma and myometrial cells, we determined the mRNA expressions of COL1A1 and COL3A1. Collagen gel contraction and wound-healing assays were performed on myometrial and leiomyoma cells. We found that UCHL1 expression was considerably higher in uterine leiomyomas than in the myometrium. COL1A1 and COL3A1 expression levels were downregulated after inhibition of UCHL1 in human leiomyoma cells. Furthermore, the elimination of UCHL1 significantly decreased the migration and contractility of leiomyoma cells. In conclusion, these results indicate that UCHL1 is involved in the growth of leiomyoma in humans. For the treatment of uterine leiomyoma, targeting UCHL1 activity may be a unique and possible therapeutic strategy.

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.

Hypoxia induces proliferation via NOX4-Mediated oxidative stress and TGF-β3 signaling in uterine leiomyoma cells

Uterine leiomyomas, the most common tumors of the female reproductive system, are known to have a hypoxic microenvironment. However, the role of such environment in leiomyoma pathobiology remains unknown. The objective was to determine the effects of hypoxia on leiomyoma cells, and the mechanisms. We found that hypoxia induces proliferation and inhibits apoptosis in human leiomyoma cells. This pro-proliferative effect was accompanied by an increase in reactive oxygen species (ROS) generation and the expression of NADPH oxidase 4 (NOX4). The specific NOX4 inhibitor GLX351322 abrogated this hypoxia-induced ROS generation, cellular proliferation, and apoptosis inhibition. To further investigate the mechanism of NOX4-mediated proliferation, we treated leiomyoma cells grown in normoxia with media from leiomyoma cells cultured under hypoxia. This resulted in increased ROS generation and NOX4 expression, suggesting the hypoxia-induced effects are mediated by an autocrine mechanism. We worked to identify the nature of this autocrine factor. We found that the expression of TGF-β3 and its downstream signaling target pSmad3, are increased in hypoxic leiomyoma cells. To examine the hypothesis that TGF-β3 is, at least, a part of this autocrine mechanism, we treated hypoxic leiomyoma cells with the HIF-1α inhibitor KC7F2 which we discovered to ameliorate the hypoxia-induced TGF-β3 expression. Furthermore, pharmacologic inhibition with the TGF-β/Smad inhibitor SB431542 reduced hypoxia-induced NOX4 expression and ROS generation and attenuated cell proliferation. Thus, we have identified a novel mechanism by which hypoxia induces proliferation in leiomyoma cells. This finding adds to our understanding of leiomyoma pathobiology and can help in identifying new therapeutic targets.

Three-dimensional human leiomyoma xenografts induce angiogenesis by inducing hypoxia inducible factor-1 alpha

OBJECTIVE

To characterize the method by which angiogenesis occurred in three-dimensional (3D) leiomyoma xenografts, and to assess the impact of hypoxia on two-dimensional (2D) and 3D myometrial and leiomyoma cells and leiomyoma xenografts in vivo.

DESIGN

Laboratory study.

SETTING

Academic research.

PATIENT(S)

Cell cultures from patient-matched myometrial and leiomyoma tissues.

INTERVENTION(S)

In vivo 3D leiomyoma xenografts from ovariectomized mice treated with gonadal hormones; myometrial and leiomyoma cells in 2D and 3D growth formats exposed to 1% oxygen.

MAIN OUTCOME MEASURE(S)

Protein expression.

RESULT(S)

Blood vessels in the xenograft estradiol group are identified with anti-mouse/anti-rat CD31/PECAM-1 antibody. Hormone-stimulated 3D leiomyoma xenografts stain positively for adrenomedullin (ADM). Myometrial cells exposed to 1% oxygen demonstrated an increase in hypoxia-inducible factor (HIF)-1α at 6 hours and a marked increase at 24 hours. Under normoxic conditions, leiomyoma cells at 6 hours show increased expression of HIF-1α, which is further increased at 24 hours. Leiomyoma cells under hypoxia demonstrated a 1.14-fold decrease in HIF-1α expression at 6 hours and no change at 24 hours. Hypoxic myometrium decreased the proangiogenic protein ADM expression at 6 hours and showed a >1.5-fold increase at 24 hours. Normoxic leiomyoma decrease ADM at 24 hours and showed a >1.5-fold increase at 24 hours of hypoxia.

CONCLUSION(S)

Hypoxia-induced HIF-1α expression facilitates angiogenesis in 3D xenografts in vivo by increasing the expression of the proangiogenic protein ADM. Angiogenesis contributes to the viability and extended survival of these xenografts. Furthermore, 2D myometrial and leiomyoma cells increase HIF-1α and ADM expression in vitro under hypoxic conditions.

Mechanical stiffness augments ligand-dependent progesterone receptor B activation via MEK 1/2 and Rho/ROCK-dependent signaling pathways in uterine fibroid cells

OBJECTIVE

To test whether mechanical substrate stiffness would influence progesterone receptor B (PRB) signaling in fibroid cells. Uterine fibroids feature an excessive extracellular matrix, increased stiffness, and altered mechanical signaling. Fibroid growth is stimulated by progestins and opposed by anti-progestins, but a functional interaction between progesterone action and mechanical signaling has not been evaluated.

DESIGN

Laboratory studies.

SETTING

Translational science laboratory.

PATIENT(S)/ANIMAL(S)

Human fibroid cell lines and patient-matched fibroid and myometrial cell lines.

INTERVENTION(S)

Progesterone receptor B-dependent reporter assays and messenger RNA quantitation in cells cultured on stiff polystyrene plates (3GPa) or soft silicone plates (930KPa). Pharmacologic inhibitors of extracellular signal-related protein kinase (ERK) kinase 1/2 (MEK 1/2; PD98059), p38 mitogen-activated protein kinase (SB202190), receptor tyrosine kinases (RTKs; nintedanib), RhoA (A13), and Rho-associated coiled-coil kinase (ROCK; Y27632).

MAIN OUTCOME MEASURE(S)

Progesterone-responsive reporter activation.

RESULT(S)

Fibroid cells exhibited higher PRB-dependent reporter activity with progesterone (P4) in cells cultured on stiff vs. soft plates. Mechanically induced PRB activation with P4 was decreased 62% by PD98059, 78% by nintedanib, 38% by A13, and 50% by Y27632. Overexpression of the Rho-guanine nucleotide exchange factor (Rho-GEF), AKAP13, significantly increased PRB-dependent reporter activity. Collagen 1 messenger RNA levels were higher in fibroid cells grown on stiff vs. soft plates with P4.

CONCLUSION(S)

Cells cultured on mechanically stiff substrates had enhanced PRB activation via a mechanism that required MEK 1/2 and AKAP13/RhoA/ROCK signaling pathways. These studies provide a framework to explore the mechanisms by which mechanical stiffness affects progesterone receptor activation.

Characterization of the role of Activator Protein 1 signaling pathway on extracellular matrix deposition in uterine leiomyoma

OBJECTIVE

To characterize the role Activator Protein 1 (AP 1) family members play in mediating extracellular matrix deposition in uterine leiomyoma.

DESIGN

Laboratory study.

SETTING

University research laboratory.

INTERVENTION(S)

Exposure of leiomyoma and myometrial cell lines to either an AP 1 inhibitor alone, AP 1 inhibitor plus transforming growth factor (TGF)ß3, or TGFß3 alone.

MAIN OUTCOME MEASURE(S)

Western immunoblot analysis was performed to assess for changes in AP 1 family member protein expression.

RESULT(S)

In patient-matched myometrial and leiomyoma cell lines, the only AP 1 member found to be elevated significantly in leiomyoma compared with myometrium was FOSB (3.47 ± 0.12-fold), whereas others were decreased significantly: FRA1 (0.67 ± 0.02-fold), FRA2 (0.45 ± 0.01-fold), c FOS (0.37 ± 0.01-fold), Phos c FOS (0.19 ± 0.02-fold), Phos c JUN (0.75 ± 0.02-fold), JUNB (0.81 ± 0.04-fold), and JUND (0.65 ± 0.03-fold). c JUN (0.93 ± 0.03-fold) concentration was reduced but at nonsignificant levels. Following stimulation with TGF ß 3, fibronectin (2.16 ± 0.14-fold) and versican (4.71 ± 0.15-fold) protein concentrations were increased at 24 hours. Collagen 1A demonstrated a time-dependent significant increased concentration beginning at 6 hours (1.32 ± 0.01-fold) and increased to (6.49 ± 0.02-fold) at 24 hours. Following treatment with AP 1 inhibitor (SR11302), there were significant reductions in Collagen 1A concentration at 4 hours (0.59 ± 0.03-fold) and 6 hours (0.42 ± 0.05-fold). Activator Protein 1 inhibition did not reduce significantly versican concentration until 6 hours of treatment (0.84 ± 0.04-fold). SR11302 also decreased significantly fibronectin concentration (0.68 ± 0.05-fold) at 8 hours of treatment.

CONCLUSION(S)

Activator Protein 1 signaling is well described in fibrotic diseases, and, herein, we demonstrated that signaling via AP 1 family members promotes extracellular matrix deposition in leiomyoma.

Steroid hormones and hormone antagonists regulate the neural marker neurotrimin in uterine leiomyoma

OBJECTIVE

To characterize the role of steroid hormone and antihormone exposure on neurotrimin (NTM) expression in human leiomyoma and myometrial tissue and cells.

DESIGN

Laboratory study of placebo and ulipristal acetate (UPA)-treated patient tissue. In vitro assessment of immortalized myometrial and leiomyoma cell lines after hormone and antihormone exposure.

SETTING

Academic research center.

PATIENT(S)

Not applicable.

INTERVENTIONS(S)

Exposure of leiomyoma cell lines to 17β-E₂, medroxyprogesterone acetate (MPA), UPA, and fulvestrant.

MAIN OUTCOME MEASURE(S)

Messenger RNA expression quantified with the use of RNASeq analysis and quantitative real-time polymerase chain reaction (qRT-PCR). Protein levels quantified by means of Western blot analysis. Immunohistochemistry (IHC) on placebo- and UPA-treated patient uterine tissue specimens.

RESULT(S)

Expression of NTM in human uterine leiomyoma specimens according to RNASeq was increased compared with myometrium (5.22 ± 0.57-fold), which was confirmed with the use of qRT-PCR (1.95 ± 0.05). Furthermore, NTM protein was elevated in leiomyoma tissue compared with matched myometrium (2.799 ± 0.575). IHC revealed increased staining intensity in leiomyoma surgical specimens compared with matched myometrium of placebo patients. Western blot analysis in immortalized leiomyoma cell lines demonstrated an up-regulation of NTM protein expression (2.4 ± 0.04). Treatment of leiomyoma cell lines with 17β-E₂ yielded a 1.98 ± 0.11-fold increase in NTM protein expression; however, treatment with fulvestrant showed no significant change compared with control. Leiomyoma cell lines demonstrated a 1.91 ± 0.97-fold increase in NTM protein expression after progesterone treatment. RNASeq analysis demonstrated a reduced expression in patient leiomyoma after UPA treatment (0.75 ± 0.14). Treatment of leiomyoma cells with UPA demonstrated a reduced total NTM protein amount (0.54 ± 0.31) in patients, which was confirmed with the use of IHC (UPA10 147.2 ± 9.40, UPA20 182.8 ± 8.98). In vitro studies with UPA treatment revealed a concentration-dependent effect that supported these findings.

CONCLUSION(S)

NTM, a neural cell adhesion molecule, is increased in leiomyoma compared with myometrium in patient tissue and in vitro models after estrogen and progesterone treatment. Down-regulation of expression occurs after UPA treatment, but not after fulvestrant exposure.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00290251.

Development and Validation of Hormonal Impact of a Mouse Xenograft Model for Human Uterine Leiomyoma

Multiple in vivo animal models for uterine leiomyoma do not adequately represent human disease based on etiology, molecular phenotype, or limited fixed life span. Our objective was to develop a xenograft model with sustained growth, by transplanting a well-established actively growing three-dimensional (3D) cell culture of human leiomyoma and myometrium in NOD/SCID ovariectomized female mice. We demonstrated continued growth to at least 12 weeks and the overexpression of extracellular matrix (ECM). Further, we confirmed maintenance of hormonal response that is comparable to human disease in situ. Leiomyoma xenografts under hormonal treatment demonstrated 8 to12-fold increase of volume over the xenografts not treated with hormones. Estradiol-treated xenografts were more cellular as compared to progesterone or combination milieu, at the end of 8-week time frame. There was also a non-statistically significant 2-4 mm³ increase in volume between 8-week and 12-week xenografts with higher matrix to cell ratio in 12-week xenografts compared to the 8-week and placebo xenografts. Increased expression of ECM proteins, fibronectin, versican, and collagens, indicated an actively growing cell matrix formation in the xenografts. In conclusion, we have developed and validated a xenograft in vivo model for uterine leiomyoma that shares the genomic and proteomic characteristics with the human surgical specimens of origin and recapitulates the most important features of the human tumors, the aberrant ECM expression that defines the leiomyoma phenotype and gonadal hormone regulation. Using this model, we demonstrated that combination of estradiol and progesterone resulted in increased cellularity and ECM production leading to growth of the xenograft tumors.

Myometrial Cells Stimulate Self-Renewal of Endometrial Mesenchymal Stem-Like Cells Through WNT5A/β-Catenin Signaling

Human endometrium undergoes cycles of proliferation and differentiation throughout the reproductive years of women. The endometrial stem/progenitor cells contribute to this regenerative process. They lie in the basalis layer of the endometrium next to the myometrium. We hypothesized that human myometrial cells provide niche signals regulating the activities of endometrial mesenchymal stem-like cells (eMSCs). In vitro coculture of myometrial cells enhanced the colony-forming and self-renewal ability of eMSCs. The cocultured eMSCs retained their multipotent characteristic and exhibited a greater total cell output when compared with medium alone culture. The expression of active β-catenin in eMSCs increased significantly after coculture with myometrial cells, suggesting activation of WNT/β-catenin signaling. Secretory factors in spent medium from myometrial cell culture produced the same stimulatory effects on eMSCs. The involvement of WNT/β-catenin signaling in self-renewal of eMSCs was confirmed with the use of WNT activator (Wnt3A conditioned medium) and WNT inhibitors (XAV939 and inhibitor of Wnt Production-2 [IWP-2]). The myometrial cells expressed more WNT5A than other WNT ligands. Recombinant WNT5A stimulated whereas anti-WNT5A antibody suppressed the colony formation, self-renewal, and T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) transcriptional activities of eMSCs. Moreover, eMSCs expressed FZD4 and LRP5. WNT5A is known to activate the canonical WNT signaling in the presence of these receptor components. WNT antagonist, DKK1, binds to LRP5/6. Consistently, DKK1 treatment nullified the stimulatory effect of myometrial cell coculture. In conclusion, our findings show that the myometrial cells are niche components of eMSCs, modulating the self-renewal activity of eMSCs by WNT5A-dependent activation of WNT/β-catenin signaling. Stem Cells 2019;37:1455-1466.

Ulipristal acetate decreases active TGF-β3 and its canonical signaling in uterine leiomyoma via two novel mechanisms

OBJECTIVE

To characterize the effect of ulipristal acetate (UPA) treatment on transforming growth factor (TGF) canonical and noncanonical signaling pathways in uterine leiomyoma tissue and cells. UPA decreased extracellular matrix in surgical specimens; we characterize the mechanism in this study.

DESIGN

Laboratory study.

SETTING

University.

INTERVENTION(S)

Exposure of leiomyoma cell lines to UPA.

MAIN OUTCOME MEASURE(S)

RNAseq was performed on matched myometrium and leiomyoma surgical specimens of placebo- and UPA-treated patients. Changes in gene expression and protein were measured using quantitative polymerase chain reaction and western immunoblot analysis, respectively.

RESULT(S)

In surgical specimen, mRNA for TGF-β3 was elevated 3.75-fold and TGFR2 was decreased 0.50-fold in placebo leiomyomas compared with myometrium. Analysis of leiomyomas from UPA-treated women by western blot revealed significant reductions of active TGF-β3 (0.64 ± 0.12-fold), p-TGFR2 (0.56 ± 0.23-fold), pSmad 2 (0.54 ± 0.04-fold), and pSmad 3 (0.65 ± 0.09-fold) compared with untreated leiomyomas. UPA treatment demonstrated statistically significant reduction in collagen 1, fibronectin, and versican proteins. Notably, there was a statistically significant increase of the extracellular matrix protein fibrillin in leiomyoma treated with UPA (1.48 ± 0.41-fold). Data from in vitro assays with physiologic concentrations of UPA supported the in vivo findings.

CONCLUSION(S)

TGF-β pathway is highly up-regulated in leiomyoma and is directly responsible for development of the fibrotic phenotype. UPA attenuates this pathway by reducing TGF-β3 message and protein expression, resulting in a reduction in TGF-β canonical signaling. In addition, UPA significantly increased fibrillin protein expression, which can serve to bind inactive TGF-β complexes. Therefore, UPA inhibits leiomyoma fibrosis by decreasing active TGF-β3 and diminishing signaling through the canonical pathway.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00290251.

A-Kinase Anchoring Protein 13 (AKAP13) Augments Progesterone Signaling in Uterine Fibroid Cells

CONTEXT

Uterine leiomyomata (fibroids) are prevalent sex hormone‒dependent tumors with an altered response to mechanical stress. Ulipristal acetate, a selective progesterone receptor (PR) modulator, significantly reduces fibroid size in patients. However, PR signaling in fibroids and its relationship to mechanical signaling are incompletely understood.

OBJECTIVE

Our prior studies revealed that A-kinase anchoring protein 13 (AKAP13) was overexpressed in fibroids and contributed to altered mechanotransduction in fibroids. Because AKAP13 augmented nuclear receptor signaling in other tissues, we sought to determine whether AKAP13 might influence PR signaling in fibroids.

METHODS AND RESULTS

Fibroid samples from patients treated with ulipristal acetate or placebo were examined for AKAP13 expression by using immunohistochemistry. In immortalized uterine fibroid cell lines and COS-7 cells, we observed that AKAP13 increased ligand-dependent PR activation of luciferase reporters and endogenous progesterone-responsive genes for PR-B but not PR-A. Inhibition of ERK reduced activation of PR-dependent signaling by AKAP13, but inhibition of p38 MAPK had no effect. In addition, glutathione S-transferase‒binding assays revealed that AKAP13 was bound to PR-B through its carboxyl terminus.

CONCLUSION

These data suggest an intersection of mechanical signaling and PR signaling involving AKAP13 through ERK. Further elucidation of the integration of mechanical and hormonal signaling pathways in fibroids may provide insight into fibroid development and suggest new therapeutic strategies for treatment.

Ulipristal Acetate and Extracellular Matrix Production in Human Leiomyomas In Vivo: A Laboratory Analysis of a Randomized Placebo Controlled Trial

In a prior randomized controlled study, patients treated with ulipristal acetate (UPA) or placebo for 3 months had a decrease in leiomyoma size. A total of 10 patients' tissue samples (5 placebo and 5 treated with 10 mg/d UPA) that underwent hysterectomy and tissue preservation were identified from this study. Quantitative real-time reverse transcriptase polymerase chain reaction and Western blotting were used to assess fold gene and protein expression of extracellular membrane (ECM) proteins: collagen 1A (COL1A), fibronectin (FN1), and versican (VCAN) of the samples. Confirmatory immunohistochemical analysis was performed. Changes in total matrix collagen were examined using Masson trichrome staining. Multiplex measurement of the matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases was performed. Compared to placebo-treated surgical specimens, 80% of the treated specimens showed decrease in VCAN protein, 60% showed decrease in FN1, but no consistent alteration in COL1A. This effect was also supported by immunohistochemistry where leiomyoma surgical specimens demonstrated decreased amount of FN1 and VCAN on UPA treatment. Increased MMP2 and decreased MMP9 in treated patient leiomyomas indicate both degradation of the matrix and inhibition of the pathway involved in matrix production. Treatment with UPA decreased fibroid volume in placebo-controlled, randomized trials. Treatment with UPA decreased gene expression and protein production in leiomyoma tissue, suggesting both an impact on water content and ECM protein concentration as a mechanism of ulipristal-mediated decrease in leiomyoma size.

Versican Proteolysis by ADAMTS Proteases and Its Influence on Sex Steroid Receptor Expression in Uterine Leiomyoma

CONTEXT

Leiomyomas have abundant extracellular matrix (ECM), with upregulation of versican, a large proteoglycan.

OBJECTIVE

We investigated ADAMTS (a disintegrin-like and metalloprotease with thrombospondin type 1 motifs) protease-mediated versican cleavage in myometrium and leiomyoma and the effect of versican knockdown in leiomyoma cells.

DESIGN

We used quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, immunohistochemistry, and RNA in situ hybridization for analysis of myometrium, leiomyoma and immortalized myometrium and leiomyoma cells. Short interfering RNA (siRNA) was used to knockdown versican in leiomyoma cells.

SETTING

This study was performed in an academic laboratory.

PATIENTS

Study subjects were women with symptomatic or asymptomatic leiomyoma.

MAIN OUTCOME MEASURES

We quantified messenger RNAs (mRNAs) for versican splice variants. We identified ADAMTS-cleaved versican in myometrium and leiomyoma and ADAMTS messenger RNAs and examined the effect of VCAN siRNA on smooth muscle differentiation and expression of estrogen and progesterone receptors.

RESULTS

The women in the symptomatic group (n = 7) had larger leiomyoma (P = 0.01), heavy menstrual bleeding (P < 0.01), and lower hemoglobin levels (P = 0.02) compared with the asymptomatic group (n = 7), but were similar in age and menopausal status. Versican V0 and V1 isoforms were upregulated in the leiomyomas of symptomatic versus asymptomatic women (P = 0.03 and P = 0.04, respectively). Abundant cleaved versican was detected in leiomyoma and myometrium, as well as in myometrial and leiomyoma cell lines. ADAMTS4 (P = 0.03) and ADAMTS15 (P = 0.04) were upregulated in symptomatic leiomyomas. VCAN siRNA did not effect cell proliferation, apoptosis, or smooth muscle markers, but reduced ESR1 and PR-A expression (P = 0.001 and P = 0.002, respectively).

CONCLUSIONS

Versican in myometrium, leiomyomas and in the corresponding immortalized cells is cleaved by ADAMTS proteases. VCAN siRNA suppresses production of estrogen receptor 1 and progesterone receptor-A. These findings have implications for leiomyoma growth.

Identification of proteins with different abundance associated with cell migration and proliferation in leiomyoma interstitial fluid by proteomics

Uterine leiomyoma is the most common female reproductive tract benign tumor. Little is known about protein composition and changes in the leiomyoma interstitial fluid (IF). The present study focused on changes in protein abundance in the IF of leiomyoma. Leiomyoma IFs and adjacent myometrial IFs were obtained and analyzed by two-dimensional electrophoresis (2-DE) coupled with mass spectrometry and western blotting for 2-DE data validation. A total of 25 unique proteins were observed to change significantly (P<0.05). Of these proteins with different abundance, 22 had not been previously identified in leiomyoma IF. In silico analysis predicted that three of these proteins were secreted via classical mechanisms, while 22 were secreted via non-classical mechanisms. Ingenuity Pathway Analysis identified 17 proteins associated with cellular migration and proliferation. Among these, phosphoglycerate mutase 1 had not been previously associated with leiomyoma. The abundance of seven proteins was further validated by western blotting. A comparative proteomic approach identified a number of proteins associated with cellular migration and proliferation, with changes in abundance in IF likely to be involved in tumor development. Further studies will be required to investigate the role of these proteins in leiomyoma IF and their possible association with tumor development and growth.

Locostatin, a disrupter of Raf kinase inhibitor protein, inhibits extracellular matrix production, proliferation, and migration in human uterine leiomyoma and myometrial cells

OBJECTIVE

To investigate the presence of Raf kinase inhibitor protein (RKIP) in human myometrium and leiomyoma as well as to determine the effect of locostatin (RKIP inhibitor) on extracellular matrix (ECM) production, proliferation, and migration in human myometrial and leiomyoma cells.

DESIGN

Laboratory study.

SETTING

Human myometrium and leiomyoma.

PATIENT(S)

Thirty premenopausal women who were admitted to the hospital for myomectomy or hysterectomy.

INTERVENTION(S)

Myometrial and leiomyoma tissues were used to investigate the localization and the expression level of RKIP through immunohistochemistry and Western blotting. Myometrial and leiomyoma cells were treated with locostatin (10 μM) to measure ECM expression by real-time polymerase chain reaction, GSK3β expression by Western blotting, cell migration by wound-healing assay, and cell proliferation by MTT assay and immunocytochemistry.

MAIN OUTCOME MEASURE(S)

The expression of RKIP in human myometrial and leiomyoma tissue; ECM components and GSK3β expression, migration, and proliferation in myometrial and leiomyoma cells.

RESULT(S)

RKIP is expressed in human myometrial and leiomyoma tissue. Locostatin treatment resulted in the activation of the mitogen-activated protein kinase (MAPK) signal pathway (ERK phosphorylation), providing a powerful validation of our targeting protocol. Further, RKIP inhibition by locostatin reduces ECM components. Moreover, the inhibition of RKIP by locostatin impaired cell proliferation and migration in both leiomyoma and myometrial cells. Finally, locostatin treatment reduced GSK3β expression. Therefore, even if the activation of MAPK pathway should increase proliferation and migration, the destabilization of GSK3β leads to the reduction of proliferation and migration of myometrial and leiomyoma cells.

CONCLUSION(S)

Our results indicate that RKIP may be involved in leiomyoma pathophysiology.

Mifepristone inhibits extracellular matrix formation in uterine leiomyoma

OBJECTIVE

To characterize the efficacy of mifepristone treatment on extracellular matrix (ECM) production in leiomyomas.

DESIGN

Laboratory study.

SETTING

University research laboratory.

PATIENT(S)

None.

INTERVENTION(S)

Treatment of human immortalized two-dimensional (2D) and three-dimensional (3D) leiomyoma and myometrial cells with mifepristone and the progestin promegestone (R5020).

MAIN OUTCOME MEASURE(S)

Expression of COL1A1, fibronectin, versican variant V0, and dermatopontin in treated leiomyoma cells by Western blot analysis and confirmatory immunohistochemistry staining of treated 3D cultures.

RESULT(S)

Treatment with progestin stimulated production of COL1A1, fibronectin, versican, and dermatopontin. Mifepristone treatment inhibited protein production of these genes, most notably with versican expression. Combination treatment with both the agonist and antagonist further inhibited protein expression of these genes. Immunohistochemistry performed on 3D cultures demonstrated generalized inhibition of ECM protein concentration.

CONCLUSION(S)

Our study demonstrated that the progesterone agonist R5020 directly stimulated extracellular matrix components COL1A1, fibronectin, versican, and dermatopontin production in human leiomyoma cells. Progesterone antagonist mifepristone decreased protein production of these genes to levels comparable with untreated leiomyoma cells.

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.

Transforming growth factor β signaling in uterine development and function

Transforming growth factor β (TGFβ) superfamily is evolutionarily conserved and plays fundamental roles in cell growth and differentiation. Mounting evidence supports its important role in female reproduction and development. TGFBs1-3 are founding members of this growth factor family, however, the in vivo function of TGFβ signaling in the uterus remains poorly defined. By drawing on mouse and human studies as a main source, this review focuses on the recent progress on understanding TGFβ signaling in the uterus. The review also considers the involvement of dysregulated TGFβ signaling in pathological conditions that cause pregnancy loss and fertility problems in women.

Leiomyoma cells in 3-dimensional cultures demonstrate an attenuated response to fasudil, a rho-kinase inhibitor, when compared to 2-dimensional cultures

Uterine leiomyomata are common benign tumors in women of reproductive age and demonstrate an attenuated response to mechanical signaling that involves Rho and integrins. To further characterize the impairment in Rho signaling, we studied the effect of Rho-kinase inhibitor, fasudil, on extracellular matrix production, in 2-dimensional (2D) and 3-dimensional (3D) cultures of leiomyoma and myometrial cells. Leiomyoma 2D cultures demonstrated a rapid decrease in gene transcripts and protein for fibronectin, procollagen 1A, and versican. In 3D cultures, fibronectin and procollagen 1A proteins demonstrated increased levels at lower concentrations of fasudil, followed by a concentration-dependent decrease. Versican protein increased up to 3-fold, whereas fibromodulin demonstrated a significant decrease of 1.92-fold. Myometrial 2D or 3D cultures demonstrated a decrease in all proteins after 72 hours of treatment. The 3D leiomyoma cultures demonstrated a significant increase in active RhoA, followed by a concentration-dependent decrease at higher concentrations. A concentration-dependent increase in phospho-extracellular regulated signal kinase and proapoptotic protein Bax was observed in 3D leiomyoma cultures. Fasudil relaxed the contraction of the 3D collagen gels caused by myometrium and leiomyoma cell growth. These findings indicate that the altered state of Rho signaling in leiomyoma was more clearly observed in 3D cultures. The results also suggest that fasudil may have clinical applicability for treatment of uterine leiomyoma.

Liarozole inhibits transforming growth factor-β3--mediated extracellular matrix formation in human three-dimensional leiomyoma cultures

OBJECTIVE

To investigate the impact of liarozole on transforming growth factor-β3 (TGF-β3) expression, TGF-β3 controlled profibrotic cytokines, and extracellular matrix formation in a three-dimensional (3D) leiomyoma model system.

DESIGN

Molecular and immunohistochemical analysis in a cell line evaluated in a three-dimensional culture.

SETTING

Laboratory study.

PATIENT(S)

None.

INTERVENTION(S)

Treatment of leiomyoma and myometrial cells with liarozole and TGF-β3 in a three-dimensional culture system.

MAIN OUTCOME MEASURE(S)

Quantitative real-time reverse-transcriptase polymerase chain reaction and Western blotting to assess fold gene and protein expression of TGF-β3 and TGF-β3 regulated fibrotic cytokines: collagen 1A1 (COL1A1), fibronectin, and versican before and after treatment with liarozole, and confirmatory immunohistochemical stains of treated three-dimensional cultures.

RESULT(S)

Both TGF-β3 gene and protein expression were elevated in leiomyoma cells compared with myometrium in two-dimensional and 3D cultures. Treatment with liarozole decreased TGF-β3 gene and protein expression. Extracellular matrix components versican, COL1A1, and fibronectin were also decreased by liarozole treatment in 3D cultures. Treatment of 3D cultures with TGF-β3 increased gene expression and protein production of COL1A1, fibronectin, and versican.

CONCLUSION(S)

Liarozole decreased TGF-β3 and TGF-β3-mediated extracellular matrix expression in a 3D uterine leiomyoma culture 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.

Vitamin D3 inhibits expression and activities of matrix metalloproteinase-2 and -9 in human uterine fibroid cells

STUDY QUESTION

Can biologically active vitamin D3 [1,25(OH)₂D3] regulate the expression and activity of matrix metalloproteinases (MMPs) in human uterine fibroid cells?

SUMMARY ANSWER

1,25(OH)₂D3 effectively reduced the expression and activities of MMP-2 and MMP-9 in cultured human uterine fibroid cells.

WHAT IS KNOWN ALREADY

Uterine fibroids (leiomyoma) express higher levels of MMP activity than adjacent normal myometrium, and this is associated with uterine fibroid pathogenesis. However, it is unknown whether 1,25(OH)₂D3 can regulate the expression and activities of MMPs in human uterine fibroid cells.

STUDY DESIGN, SIZE, DURATION

Surgically removed fresh fibroid tissue was used to generate primary uterine fibroid cells.

PARTICIPANTS/MATERIALS, SETTING, METHODS

An immortalized human uterine fibroid cell line (HuLM) and/or primary human uterine fibroid cells isolated from fresh fibroid tissue were used to examine the expression of several MMPs, tissue inhibitors of metalloproteinases (TIMP) 1 and 2 and the activities of MMP-2 and MMP-9 after 1,25(OH)₂D3 treatment. Real-time PCR and western blots analyses were used to measure mRNA and protein expression of MMPs, respectively. Supernatant cell culture media were analyzed for MMP-2 and MMP-9 activities using a gelatin zymography assay.

MAIN RESULTS AND THE ROLE OF CHANCE

1-1000 nM 1,25(OH)₂D3 significantly reduced mRNA levels of MMP-2 and MMP-9 in HuLM cells in a concentration-dependent manner (P < 0.5 to P < 0.001). The mRNA levels of MMP-1, MMP-3, MMP-13 and MMP-14 in HuLM cells were also reduced by 1,25(OH)₂D3. 1,25(OH)₂D3 significantly reduced MMP-2 and MMP-9 protein levels in a concentration-dependent manner in both HuLM and primary uterine fibroid cells (P < 0.05 to P < 0.001). Moreover, 1,25(OH)₂D3 increased the mRNA levels of vitamin D receptor (VDR) and TIMP-2 in a concentration-dependent manner in HuLM cells (P < 0.05 to P < 0.01). 1,25(OH)₂D3 also significantly increased protein levels of VDR and TIMP-2 in all cell types tested (P < 0.05 to P < 0.001). Gelatin zymography revealed that pro-MMP-2, active MMP-2 and pro-MMP-9 were down-regulated by 1,25(OH)₂D3 in a concentration-dependent manner; however, the active MMP-9 was undetectable.

LIMITATIONS, REASONS FOR CAUTION

This study was performed using in vitro uterine fibroid cell cultures and the results were extrapolated to in vivo situation of uterine fibroids. Moreover, in this study the interaction of vitamin D3 with other regulators such as steroid hormone receptors was not explored.

WIDER IMPLICATIONS OF THE FINDINGS

This study reveals an important biological function of 1,25(OH)₂D3 in the regulation of expression and activities of MMP-2 and MMP-9. Thus, 1,25(OH)₂D3 might be a potential effective, safe non-surgical treatment option for human uterine fibroids.

Integrin β1 regulates leiomyoma cytoskeletal integrity and growth

Uterine leiomyomas are characterized by an excessive extracellular matrix, increased mechanical stress, and increased active RhoA. Previously, we observed that mechanical signaling was attenuated in leiomyoma, but the mechanisms responsible remain unclear. Integrins, especially integrin β1, are transmembrane adhesion receptors that couple extracellular matrix stresses to the intracellular cytoskeleton to influence cell proliferation and differentiation. Here we characterized integrin and laminin to signaling in leiomyoma cells. We observed a 2.25±0.32 fold increased expression of integrin β1 in leiomyoma cells, compared to myometrial cells. Antibody-mediated inhibition of integrin β1 led to significant growth inhibition in leiomyoma cells and a loss of cytoskeletal integrity. Specifically, polymerization of actin filaments and formation of focal adhesions were reduced by inhibition of integrin β1. Inhibition of integrin β1 in leiomyoma cells led to 0.81±0.02 fold decrease in active RhoA, and resembled levels found in serum-starved cells. Likewise, inhibition of integrin β1 was accompanied by a decrease in phospho-ERK. Compared to myometrial cells, leiomyoma cells demonstrated increased expression of integrin α6 subunit to laminin receptor (1.91±0.11 fold), and increased expression of laminin 5α (1.52±0.02), laminin 5β (3.06±0.92), and laminin 5γ (1.66±0.06). Of note, leiomyoma cells grown on laminin matrix appear to realign themselves. Taken together, the findings reveal that the attenuated mechanical signaling in leiomyoma cells is accompanied by an increased expression and a dependence on integrin β1 signaling in leiomyoma cells, compared to myometrial cells.

Leiomyoma fibrosis inhibited by liarozole, a retinoic acid metabolic blocking agent

OBJECTIVE

To study the influence of liarozole on leiomyoma cell proliferation and extracellular matrix (ECM) gene expression in immortalized leiomyoma cells.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S)

None.

INTERVENTION(S)

Tissue culture, real-time reverse transcription-polymerase chain reaction, Western blot.

MAIN OUTCOME MEASURE(S)

Proliferation, messenger RNA (mRNA), and ECM protein expression.

RESULT(S)

Proliferation of leiomyoma cells was inhibited by treatment with liarozole at suprapharmacologic concentrations. The mRNA and protein expression of COL1A1, COL4A2, versican, fibromodulin, and fibronectin was increased in untreated leiomyoma cells compared with untreated patient-matched myometrial cells. Extracellular matrix mRNA expression was decreased in a dose-dependent manner in leiomyoma cells treated with pharmacologic concentrations of liarozole. In addition, myometrial cells treated with liarozole demonstrated no statistically significant alteration in ECM regulation.

CONCLUSION(S)

Liarozole inhibited ECM protein production at pharmacologic concentrations in immortalized human leiomyoma cells. Retinoic acid metabolic blocking agents represent a potential therapeutic drug family for human leiomyomas.

The endothelin axis in uterine leiomyomas: new insights

The endothelin axis, comprising endothelin-1 (ET-1) and its receptors (ETA and ETB), is involved in the pathophysiology of different human tumors. Here we review conventional approaches and gene expression profiling indicating the association of ET-1 and its cognate receptors with human and rat leiomyomas, the most common benign tumors of myometrium. Specifically, ET-1/ETA interactions affect human and rat leiomyoma cell proliferation through protein kinase C and mitogen-activated protein kinase-dependent signaling pathways. Recent experiments demonstrate that the ET-1 axis exerts a potent antiapoptotic effect involving sphingolipid metabolism and prostaglandin-endoperoxide synthase 2/prostaglandin system in the rat Eker leiomyoma tumor-derived ELT3 cell line. Evidence supports that steroid hormones, growth factors, and extracellular matrix are key regulators of the leiomyoma growth. Interestingly, the ET-1 axis is under steroid hormones and can cooperate with these growth factors. Therefore, ET-1 alone or in association with these factors could contribute to the complex regulation of uterine tumor growth, such as proliferation, survival, and extracellular matrix production. This review summarizes current knowledge and emerging data on ET-1 in uterine leiomyoma pathology.

Microarray analysis in gynaecology and its findings: a systematic review

Microarray technology is a promising method for investigating gynaecological benign pathology. This systematic review examined various parameters of the design of these studies, the methods used and the gene outcome in these diseases. Electronic searches were performed in Medline (up to April 2009). An overall representation of important genes for each disease detected was performed. The results showed genes were up-regulated or down-regulated. However, studies suffer from several flaws in their design, the sample size employed and the reporting method. In conclusion, a significant amount of work has been performed on benign gynaecological diseases using microarray technology. New trial designs need to be employed that incorporate microarray reporting standards. New research directions should evolve based on these results.

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.

1,25-Dihydroxyvitamin D3 reduces TGF-beta3-induced fibrosis-related gene expression in human uterine leiomyoma cells

BACKGROUND

Uterine leiomyomas (fibroids) are the most common benign estrogen-dependent tumors of premenopausal women. TGF-β3 up-regulates the synthesis of many of extracellular matrix proteins that are associated with tissue fibrosis.

OBJECTIVE

To examine the effect of 1,25-dihydroxyvitamin D(3) (vitamin D(3)) on TGF-β3-induced fibrosis-related protein expression in immortalized human uterine leiomyoma (HuLM) cells.

METHODS

HuLM cells were treated with TGF-β3 with or without vitamin D(3). Western blot analyses were employed to test the effect of vitamin D(3) on TGF-β3-induced protein expression of collagen type 1, fibronectin, and plasminogen activator inhibitor-1 proteins. Western blots as well as immunofluorescence analyses were used to verify the effect of vitamin D(3) on TGF-β3-induced Smad activation involved in extracellular matrix protein synthesis and deposition, which ultimately lead to tissue fibrosis.

RESULTS

We observed that TGF-β3 induced fibronectin and collagen type 1 protein expression in HuLM cells, and that effect was suppressed by vitamin D(3). TGF-β3 also induced protein expression of plasminogen activator inhibitor-1, an important TGF-β target, in HuLM cells, which was also inhibited by vitamin D(3). Additionally, TGF-β3 induced phosphorylation of Smad2 as well as nuclear translocation of Smad2 and Smad3 in HuLM cells, whereas vitamin D significantly reduced all these TGF-β3-mediated effects. Therefore, our results suggest that vitamin D(3) has consistently reduced TGF-β3 effects that are involved in the process of fibrosis in human leiomyoma cells.

CONCLUSION

Vitamin D(3) is an antifibrotic factor that might be potentially useful as a novel therapeutic for nonsurgical treatment of benign uterine fibroids.

CDB-4124 does not cause apoptosis in cultured fibroid cells

OBJECTIVE

Selective progesterone receptor modulators (SPRMs), such as asoprisnil (J867) and ulipristal (CDB-2914), have been shown to reduce fibroid volume in vivo and to induce apoptosis in vitro. CDB-4124 (telapristone), a SPRM with different side groups, also reduced fibroid volume in vivo, and we hypothesized that this SPRM would also cause apoptosis in cultured fibroid cells.

METHODS

Immortalized, progesterone receptor-positive fibroid cells, known to be capable of apoptosis, were grown to 80% confluence in serum-containing media. Cells were then treated for 48 hours in serum-free media with 0, 10, 100, or 1000 nmol/L CDB-4124. Actinomycin-D and staurosporine were used as positive controls to induce apoptosis. Apoptosis was quantified using a TUNEL-fluorescein kit. Images were captured with a widefield-fluorescence microscope and analyzed using MetaMorph image analysis software. To validate results, Western blots of total cell lysates were probed for cleaved caspase-3 (c-CASP3). Experiments were repeated 3 times using independent cell batches.

RESULTS

Analysis of 19 712 nuclei indicated 14.8% ± 10.9% (mean ± SEM), 8.4% ± 4.6%, 8.2% ± 4.7%, and 9.3% ± 6.3% apoptosis in 0, 10, 100, and 1000 nmol/L CDB-4124-treated cells, respectively. There was no evidence of elevated c-CASP3 over vehicle control after treatment with CDB-4124.

CONCLUSION

CDB-4124 did not significantly induce apoptosis in cultured fibroid cells under the conditions described suggesting apoptosis may not be the main pathway responsible for CDB-4124-induced fibroid shrinkage. Variations in SPRM biological effects may be due to differences in fibroid source cells, binding kinetics, or extracellular matrix characteristics, and can be exploited in further investigations of the mechanisms of action of SPRMs in fibroid biology.

Novel, orally active selective progesterone receptor modulator CP8947 inhibits leiomyoma cell proliferation without adversely affecting endometrium or myometrium

Uterine leiomyomas are highly prevalent and often symptomatic, but current medical therapies are limited. A novel, potent, selective, orally active therapy is needed. The goal of these studies was to determine the progesterone receptor (PR) specificity and activation, endometrial response, and impact on leiomyoma cell proliferation and extracellular matrix (ECM) production of the novel non-steroidal selective progesterone receptor modulators (SPRMs) CP8863 and CP8947. In vitro progestational activity was assessed by alkaline phosphatase assay and ER-α expression. In vivo progestational activity was assayed by the McPhail assay. Proliferation and gene expression studies were performed in immortalized human leiomyoma and myometrial cells. Both CP8863 and CP8947 were highly selective for progesterone receptor (PR) but not for ER-α, AR, and GR. Both compounds induced alkaline phosphatase comparably to progesterone, while CP8947 induced ER-α in leiomyoma cells but not myometrial cells. CP8947 was progestational in rabbit endometrium. Nanomolar CP8947 treatment inhibited human leiomyoma but not myometrial cell proliferation. Extracellular matrix components were decreased in leiomyoma cells, including COL1A1 and COL7A1 at nanomolar concentrations. CP8947 was a potent novel non-steroidal SPRM that was selective for PR, demonstrated progestational activity in endometrium, inhibited leiomyoma cell proliferation and decreased ECM component production, without disrupting myometrial cell proliferation.

Transforming growth factor beta3 regulates the versican variants in the extracellular matrix-rich uterine leiomyomas

Uterine leiomyoma are common, benign tumors that are enriched in extracellular matrix. The tumors are characterized by a disoriented and loosely packed collagen fibril structure similar to other diseases with disrupted Transforming growth factor beta (TGF-beta) signaling. Here we characterized TGF-beta3 signaling and the expression patterns of the critical extracellular matrix component versican in leiomyoma and myometrial tissue and cell culture. We also demonstrate the regulation of the versican variants by TGF-beta3. Using leiomyoma and matched myometrium from 15 patients, messenger RNA (mRNA) from leiomyoma and myometrium was analyzed by semiquantitative real time reverse transcription-polymerase chain reaction (RT-PCR), while protein analysis was done by western blot. Transforming growth factor beta3 transcripts were increased 4-fold in leiomyoma versus matched myometrium. Phosphorylated-TGF-beta RII and phosphorylated-Smad 2/3 complex were greater in leiomyoma as documented by Western blot. The inhibitor Smad7 transcripts were decreased 0.44-fold. The glycosaminoglycan (GAG)-rich versican variants were elevated in leiomyoma versus myometrial tissue: specifically V0 (4.27 +/- 1.12) and V1 (2.01 +/- 0.27). Treatment of leiomyoma and myometrial cells with TGF-beta3 increased GAG-rich versican variant expression 7 to 12 fold. Neutralizing TGF-beta3 antibody decreased the expression of the GAG-rich versican variants 2 to 8 fold in leiomyoma cells. Taken together, the aberrant production of excessive and disorganized extracellular matrix that defines the leiomyoma phenotype involves the activation of the TGF-beta signaling pathway and excessive production of GAG-rich versican variants.

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.

Mechanical homeostasis is altered in uterine leiomyoma

OBJECTIVE

Uterine leiomyoma produce an extracellular matrix (ECM) that is abnormal in its volume, content, and structure. Alterations in ECM can modify mechanical stress on cells and lead to activation of Rho-dependent signaling and cell growth. Here we sought to determine whether the altered ECM that is produced by leiomyoma was accompanied by an altered state of mechanical homeostasis.

STUDY DESIGN

We measured the mechanical response of paired leiomyoma and myometrial samples and performed immunogold, confocal microscopy, and immunohistochemical analyses.

RESULTS

Leiomyoma were significantly stiffer than matched myometrium. The increased stiffness was accompanied by alteration of the ECM, cell shape, and cytoskeleton in leiomyoma, compared with myometrial samples from the same uterus. Levels of AKAP13, a protein that is known to activate Rho, were increased in leiomyoma compared to myometrium. AKAP13 was associated with cytoskeletal filaments of immortalized leiomyoma cells.

CONCLUSION

Leiomyoma cells are exposed to increased mechanical loading and show structural and biochemical features that are consistent with the activation of solid-state signaling.

Selective progesterone receptor modulator asoprisnil down-regulates collagen synthesis in cultured human uterine leiomyoma cells through up-regulating extracellular matrix metalloproteinase inducer

BACKGROUND

A recent clinical trial demonstrated that selective progesterone receptor modulator asoprisnil is effective in reducing uterine leiomyoma volume. We investigated the effects of asoprisnil in vitro on the expression of the extracellular matrix (ECM)-remodeling enzymes and collagens in cultured leiomyoma and matching normal myometrial cells.

METHODS

The expression of extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMPs) and collagens were assessed by western blot analysis.

RESULTS

Untreated cultured leiomyoma cells had significantly lower EMMPRIN (P < 0.05), MMP-1 (P < 0.05) and membrane type 1-MMP (MT1-MMP) (P < 0.01) protein contents, but significantly higher TIMP-1 (P < 0.05), TIMP-2 (P < 0.01), type I (P < 0.05) and type III (P < 0.01) collagen protein contents compared with untreated cultured myometrial cells. Treatment with asoprisnil at concentrations > or =10(-7) M for 48 h significantly (P < 0.05) increased EMMPRIN, MMP-1 and MT1-MMP protein contents, and decreased TIMP-1 (P < 0.05), TIMP-2 (P < 0.01), type I (P < 0.01) and type III (P < 0.05 at 10(-7) M; P < 0.01 at 10(-6) M) collagen protein contents in cultured leiomyoma cells compared with control cultures. However, asoprisnil treatment did not affect the protein contents of ECM-remodeling enzymes and collagens in cultured myometrial cells.

CONCLUSIONS

These results suggest that asoprisnil may reduce collagen deposit in the ECM of cultured leiomyoma cells through decreasing collagen synthesis and enhancing the expression of EMMPRIN, MMPs and TIMPs without comparable effects on cultured myometrial cells.