Development and validation of a three-dimensional in vitro model for uterine leiomyoma and patient-matched myometrium

Simvastatin induces degradation of the extracellular matrix in human leiomyomata: novel in vitro, in vivo, and patient level evidence of matrix metalloproteinase involvement

OBJECTIVES

To assess the effect of simvastatin on uterine leiomyoma growth and extracellular matrix (ECM) deposition.

DESIGN

Laboratory analysis of human leiomyoma cell culture, xenograft in a mouse model, and patient tissue from a clinical trial.

SETTING

Academic research center.

PATIENT(S)

Tissue culture from human leiomyoma tissue and surgical leiomyoma tissue sections from a placebo-controlled randomized clinical trial.

INTERVENTION(S)

Simvastatin treatment.

MAIN OUTCOME MEASURE(S)

Serum concentrations, xenograft volumes, and protein expression.

RESULTS

Mice xenografted with 3-dimensional human leiomyoma cultures were divided as follows: 7 untreated controls; 12 treated with activated simvastatin at 10 mg/kg body weight; and 15 at 20 mg/kg body weight. Simvastatin was detected in the serum of mice injected at the highest dose. Xenograft volumes were significantly smaller (mean 53% smaller at the highest concentration). There was dissolution of compact ECM, decreased ECM formation, and lower collagen protein expression in xenografts. Membrane type 1 matrix metalloproteinase was increased in vitro and in vivo. Matrix metalloproteinase 2 and low-density lipoprotein receptor-related protein 1 were increased in vitro.

CONCLUSIONS

Simvastatin exhibited antitumoral activity with ECM degradation and decreased leiomyoma tumor volume in vivo. Activation of the matrix metalloproteinase 2, membrane type 1 matrix metalloproteinase, and low-density lipoprotein receptor-related protein 1 pathway may explain these findings.

High levels of hypusinated eIF5A in leiomyoma and leiomyosarcoma pathologies: a possible novel therapeutic target

RESEARCH QUESTION

Is the hypusinated form of the eukaryotic translation initiation factor 5A (EIF5A) present in human myometrium, leiomyoma and leiomyosarcoma, and does it regulate cell proliferation and fibrosis?

DESIGN

The hypusination status of eIF5A in myometrial and leiomyoma patient-matched tissues was evaluated by immunohistochemistry and Western blotting as well as in leiomyosarcoma tissues by immunohistochemistry. Myometrial, leiomyoma and leiomyosarcoma cell lines were treated with N1-guanyl-1,7-diaminoheptane (GC-7), responsible for the inhibition of the first step of eIF5A hypunization, and the proliferation rate was determined by MTT assay; fibronectin expression was analysed by Western blotting. Finally, expression of fibronectin in leiomyosarcoma tissues was detected by immunohistochemistry.

RESULTS

The hypusinated form of eIF5A was present in all tissues examined, with an increasing trend of hypusinated eIF5A levels from normal myometrium to neoplastic benign leiomyoma up to neoplastic malignant leiomyosarcoma. The higher levels in leiomyoma compared with myometrium were confirmed by Western blotting (P = 0.0046). The inhibition of eIF5A hypusination, with GC-7 treatment at 100 nM, reduced the cell proliferation in myometrium (P = 0.0429), leiomyoma (P = 0.0030) and leiomyosarcoma (P = 0.0044) cell lines and reduced the expression of fibronectin in leiomyoma (P = 0.0077) and leiomyosarcoma (P = 0.0280) cells. The immunohistochemical staining of leiomyosarcoma tissue revealed that fibronectin was highly expressed in the malignant aggressive (central) part of the leiomyosarcoma lesion, where hypusinated eIF5A was also highly represented.

CONCLUSIONS

These data support the hypothesis that eIF5A may be involved in the pathogenesis of myometrial benign and malignant pathologies.

Curcumin inhibits human leiomyoma xenograft tumor growth and induces dissolution of the extracellular matrix

OBJECTIVE

To determine whether a curcumin-supplemented diet would prevent and/or treat uterine leiomyoma growth in our mouse xenograft model.

DESIGN

Animal study.

SETTING

Laboratory study.

PATIENT(S)

N/A.

INTERVENTION(S)

Curcumin-supplemented diet.

MAIN OUTCOME MEASURE(S)

Dietary intake, blood concentrations, tumor size, extracellular matrix protein concentrations, apoptosis markers.

RESULT(S)

We found that curcumin was well tolerated as a dietary supplement, free curcumin and its metabolites were detected in the serum, and exposure resulted in approximately 60% less leiomyoma xenograft growth as well as dissolution of the peripheral extracellular matrix architecture of the xenografts. The production of matrix proteins, including collagens, decreased, whereas the number of apoptotic cells in the xenografts increased. Additionally, when xenografts were placed in a uterine intramural location, we found a significantly increased apoptotic response to curcumin in the diet.

CONCLUSION(S)

Mice on a diet supplemented with curcumin could achieve serum concentrations sufficient to regulate human leiomyoma xenograft growth, and curcumin could play both preventive and curative roles in the treatment of uterine leiomyoma as an oral nutritional supplement.

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.

Uterine Fibroids: Hiding in Plain Sight

Uterine fibroids (leiomyomas) are present in >75% of women and can cause serious morbidity. They are by far the leading cause of hysterectomy. Fibroids are a complex mixture of cells that include fibroblasts and smooth muscle cells. Rich in extracellular matrix, they typically arise through somatic mutations, most commonly MED12. Their lack of growth inhibition and their ability to have facets of malignancy yet be histologically and biologically benign provide opportunities to explore basic processes. To date, the mechanisms responsible for growth and development of leiomyomas are an enigma. This review provides an overview of current understanding and future directions for clinical and basic research of fibroids.

Hop and artichoke extracts inhibit expression of extracellular matrix components in uterine leiomyoma cells

OBJECTIVE

To screen 14 different plant extracts for their antifibrotic effect on human primary leiomyoma and healthy myometrial cells.

DESIGN

Preclinical study.

SETTING

University research laboratory.

PATIENT(S)

Human uterine leiomyoma and matched myometrial tissues were obtained from Caucasian premenopausal women with symptomatic uterine fibroids at the time of hysterectomy.

INTERVENTION(S)

Primary human leiomyoma and myometrial cells were cultured in the absence or presence of the plant extracts.

MAIN OUTCOME MEASURE(S)

Quantification of the expression of extracellular matrix components, such as fibronectin 1 (FN1), collagen type I alpha 1 (COL1A1), and versican (VCAN), and the profibrotic growth factor activin A or inhibin beta A subunit (INHBA).

RESULT(S)

The cells were treated with the 14 extracts for 48 hours, and we measured FN1 messenger RNA (mRNA) expression. Of the 14 extracts, about (ABO) ABO-2 (hop) and ABO-9 (artichoke) significantly reduced FN1 expression in both the cell types. Next, we evaluated the effect of fractions of these 2 extracts on the mRNA expression of FN1 and other extracellular matrix components, such as COL1A1, VCAN, and INHBA, in leiomyoma and myometrial cells. We found that ABO-2 (hop) and ABO-9 (artichoke) as well as their fractions, ABO-AR-2016-015 (fraction of ABO-2) and ABO-AR-2014-168 (fraction of ABO-9), reduced the mRNA expression of FN1, COL1A1, VCAN, and INHBA in primary leiomyoma cells. In primary myometrial cells, the mRNA expression of FN1, COL1A1, VCAN, and INHBA was not greatly affected.

CONCLUSION(S)

These results suggest that the hop and artichoke extracts possess antifibrotic properties and support additional evaluation using in vivo models.

Markers of Inflammation and Vascular Parameters in Selective Progesterone Receptor Modulator (Ulipristal Acetate)-Treated Uterine Fibroids

The exact mechanism of selective progesterone receptor modulator action in leiomyoma still challenges researchers. The aim of the study was to assess the effects of ulipristal acetate (UPA) on immunoexpression of inflammatory markers and vascularization in fibroids. UPA-treated patients were divided into three groups: (1) good response (≥25% reduction in volume of fibroid), (2) weak response (insignificant volume reduction), (3) and no response to treatment (no decrease or increase in fibroid volume). The percentage of TGFβ, IL6, IL10, CD117, and CD68-positive cells were significantly lower in the group with a good response to treatment vs. the control group. Moreover, the percentage of IL10 and CD68-positive cells in the group with a good response to treatment were also significantly lower compared to the no response group. Additionally, a significant decrease in the percentage of IL10-positive cells was found in the good response group vs. the weak response group. There were no statistical differences in the percentage of TNFα-positive cells and vessel parameters between all compared groups. The results of the study indicate that a good response to UPA treatment may be associated with a decrease of inflammatory markers, but it does not influence myoma vascularization.

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.

Tools, techniques, and future opportunities for characterizing the mechanobiology of uterine myometrium

The myometrium is the smooth muscle layer of the uterus that generates the contractions that drive processes such as menstruation and childbirth. Aberrant contractions of the myometrium can result in preterm birth, insufficient progression of labor, or other difficulties that can lead to maternal or fetal complications or even death. To investigate the underlying mechanisms of these conditions, the most common model systems have conventionally been animal models and human tissue strips, which have limitations mostly related to relevance and scalability, respectively. Myometrial smooth muscle cells have also been isolated from patient biopsies and cultured in vitro as a more controlled experimental system. However, in vitro approaches have focused primarily on measuring the effects of biochemical stimuli and neglected biomechanical stimuli, despite the extensive evidence indicating that remodeling of tissue rigidity or excessive strain is associated with uterine disorders. In this review, we first describe the existing approaches for modeling human myometrium with animal models and human tissue strips and compare their advantages and disadvantages. Next, we introduce existing in vitro techniques and assays for assessing contractility and summarize their applications in elucidating the role of biochemical or biomechanical stimuli on human myometrium. Finally, we conclude by proposing the translation of "organ on chip" approaches to myometrial smooth muscle cells as new paradigms for establishing their fundamental mechanobiology and to serve as next-generation platforms for drug development.

Biomaterial strategies to replicate gynecological tissue

Properties of native tissue can inspire biomimetic in vitro models of gynecological disease.

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.

SATB2 and NGR1: potential upstream regulatory factors in uterine leiomyomas

PURPOSE

We attempted to identify the genes involved in the pathogenesis of uterine leiomyomas, under a hypothesis that the aberrant expression of upstream regulatory genes caused by aberrant DNA methylation is involved in the onset and development of uterine leiomyomas.

METHODS

To find such genes, we compared genome-wide mRNA expression and DNA methylation in uterine leiomyomas and adjacent normal myometrium. Analysis of the data by Ingenuity Pathway Analysis software identified SATB2 which is known to be an epigenetic regulator, and NRG1 as candidate upstream regulatory genes. To infer the functions of these genes, human uterine smooth muscle cell lines overexpressing SATB2 or NRG1 genes were established (SATB2 or NRG1 lines), and their transcriptomes and pathways were analyzed.

RESULTS

SATB2 and NRG1 were confirmed to be hypermethylated and upregulated in most uterine leiomyoma specimens (nine to 11 of the 11 cases). Among the established cell lines, morphological changes from spindle-like forms to fibroblast-like forms with elongated protrusions were observed in only the SATB2 line. Pathway analysis revealed that WNT/β-catenin and TGF-β signaling pathways which are related to the pathogenesis of uterine leiomyomas were activated in both SATB2 and NRG1 lines. In addition, signaling of growth factors including VEGF, PDGF, and IGF1, and retinoic acid signaling were activated in the SATB2 and NRG1 lines, respectively.

CONCLUSIONS

These results indicate that SATB2 and NRG1 overexpression induced many of the signaling pathways that are considered to be involved in the pathogenesis of uterine leiomyomas, suggesting that these genes have roles as upstream regulatory factors.

Simvastatin, at clinically relevant concentrations, affects human uterine leiomyoma growth and extracellular matrix production

OBJECTIVE

To observe the antifibroid effects of therapeutic concentrations of simvastatin, which interferes with cholesterol biosynthesis, a known precursor of five major classes of steroid hormones, including progesterone and estrogen, which play a major role in the development and growth of uterine leiomyomas.

DESIGN

Two-dimensional and three-dimensional cell culture study of immortalized human leiomyoma and patient-matched myometrium cells treated with simvastatin.

SETTING

University laboratory.

PATIENT(S)

None.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

Cell proliferation, alteration in apoptotic signaling pathways, and extracellular matrix (ECM) protein production.

RESULT(S)

Simvastatin demonstrated a concentration-dependent antiproliferative effect on both the leiomyoma cells and the patient-matched myometrium cells, but a higher inhibitory effect at lower concentrations of simvastatin was observed in leiomyoma cells. Simvastatin also regulated leiomyoma cell apoptosis through a concentration-dependent increase in activity of caspase-3. Simvastatin significantly inhibited expression of major ECM proteins collagen I, collagen III, fibronectin, versican, and brevican in leiomyoma cells at concentrations as low as 10^-9 mol/L within 48 hours of exposure.

CONCLUSION(S)

Simvastatin induces apoptosis in uterine leiomyoma cells at low concentrations, as evidenced by increased active caspase levels. Furthermore, inhibited production of the ECM proteins may lead to reduction in tumor size. Simvastatin may represent a novel therapeutic treatment strategy for uterine leiomyomas.

Ulipristal Acetate Mediates Decreased Proteoglycan Expression Through Regulation of Nuclear Factor of Activated T-Cells (NFAT5)

Nuclear factor of activated T-cells (NFAT5) is a tissue specific, osmoadaptive transcription factor essential for the control of hydration homeostasis in mammalian cells. Nuclear factor of activated T-cells regulates osmolyte transporters aldo-keto reductase family 1 member B1 (AKR1B1) and solute carrier family 5 member 3 (SLC5A3) to maintain fluid equilibrium in cells. The osmotic potential of the extracellular matrix of leiomyomas is attributed to the role of proteoglycans. In leiomyoma cells, NFAT5 is overexpressed compared to myometrial cells. The selective progesterone receptor modulator, ulipristal acetate, has been reported to decrease the size of leiomyomas in clinical trials. When treated with ulipristal acetate, both patient leiomyoma tissue and leiomyoma cells grown in 3-dimensional cultures show a decrease in the expression of NFAT5 protein, solute transporters AKR1B1 and SLC5A3, and results in an associated decline in the expression of proteoglycans, versican, aggrecan, and brevican. In summary, ulipristal acetate induces changes in leiomyoma cell osmoregulation which result in a decrease in proteoglycan expression.

Omega-3 fatty acids modulate the lipid profile, membrane architecture, and gene expression of leiomyoma cells

Uterine leiomyomas (fibroids or myomas) are the most common benign tumors of premenopausal women and new medical treatments are needed. This study aimed to determine the effects of omega-3 fatty acids on the lipid profile, membrane architecture and gene expression patterns of extracellular matrix components (collagen1A1, fibronectin, versican, or activin A), mechanical signaling (integrin β1, FAK, and AKAP13), sterol regulatory molecules (ABCG1, ABCA1, CAV1, and SREBF2), and mitochondrial enzyme (CYP11A1) in myometrial and leiomyoma cells. Myometrial tissues had a higher amount of arachidonic acid than leiomyoma tissues while leiomyoma tissues had a higher level of linoleic acid than myometrial tissues. Treatment of primary myometrial and leiomyoma cells with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) reduced the monounsaturated fatty acid (MUFA) content and increased the polyunsaturated fatty acid (PUFA) content in both cell types. Myometrial and leiomyoma cell membranes were in the liquid-crystalline phase, but EPA- and DHA-treated cells had decreased membrane fluidity. While we found no changes in the mRNA expression of ECM components, EPA and DHA treatment reduced levels of ABCG1, ABCA1, and AKAP13 in both cell types. EPA and DHA also reduced FAK and CYP11A1 expression in myometrial cells. The ability of omega-3 fatty acids to remodel membrane architecture and downregulate the expression of genes involved in mechanical signaling and lipid accumulation in leiomyoma cells offers to further investigate this compound as preventive and/or therapeutic option.

Factors affecting the loss of MED12-mutated leiomyoma cells during in vitro growth

Uterine leiomyomas (UL) are the most prevalent symptomatic human tumors at all and somatic mutations of the gene encoding mediator subcomplex 12 (MED12) constitute the most frequent driver mutations in UL. Recently, a rapid loss of mutated cells during in vitro growth of UL-derived cell cultures was reported, resulting in doubts about the benefits of UL-derived cell cultures. To evaluate if the rapid loss of MED12-mutated cells in UL cell cultures depends on in vitro passaging, we set up cell cultures from nine UL from 40–50 year old Caucasian patients with at least one UL. Cultured UL cells were investigated for loss of MED12-mutated cells. Genetic characterization of native tumor samples and adjacent myometrium was done by array analysis. “Aged” primary cultures without passaging were compared to cells of three subsequent passages. Comparative analyses of the mutated/non-mutated ratios between native tissue, primary cells, and cultured tumor cells revealed a clear decrease of MED12-mutated cells. None of the tumors showed gross alterations of the array profiles, excluding the presence of gross genomic imbalances besides the MED12 mutations as a reason for the intertumoral variation in the loss of MED12-mutated cells. Albeit at a lesser rate, loss of MED12-mutated cells from cell cultures of UL occurs even without passaging thus indicating the requirement of soluble factors or matrix components lacking in vitro. Identification of these factors can help to understand the mechanisms of the growth of the most frequent type of uterine leiomyomas and to decipher novel drug targets.

Comparative systems genetics view of endometriosis and uterine leiomyoma: Two sides of the same coin?

Endometriosis (EM) and uterine leiomyoma (UL) are two most frequent benign tumors of monoclonal origin affecting about 30% of all women in their reproductive age. Modern molecular technologies have made a tremendous impact in understanding both disorders. Here is the first comparative analysis of molecular mechanisms underlying development of EM and UL as it looks from the platform of systems genetics. Similarities and differences of EM and UL at their incipient stages are enlightened with special emphasis on their gene networks, gene expression, and epigenetic regulation, of pathologic development. The analysis substantiates a new hypothesis postulating tumors as outgrowths of the stem cells with mesenchymal commitment lineage (mSC) which migrate from the endometrium/myometrium junctional zone of the uterus. Comparative analysis has revealed basic similarities of molecular pathogenesis of EM and UL suggesting molecular syntropy of both disorders. Peculiarities of the epigenetic landscape determining development of mSC may explain the existence of different clinical forms of EM and UL as well as their unique clinical manifestation. Some perspectives for practical and scientific application in EM and UL studies of this new hypothesis are outlined.

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.

Simvastatin potently induces calcium-dependent apoptosis of human leiomyoma cells

Statins are drugs commonly used for the treatment of high plasma cholesterol levels. Beyond these well known lipid-lowering properties, they possess broad-reaching effects in vivo, including antitumor effects. Statins inhibit the growth of multiple tumors. However, the mechanisms remain incompletely understood. Here we show that simvastatin inhibits the proliferation of human leiomyoma cells. This was associated with decreased mitogen-activated protein kinase signaling and multiple changes in cell cycle progression. Simvastatin potently stimulated leiomyoma cell apoptosis in a manner mechanistically dependent upon apoptotic calcium release from voltage-gated calcium channels. Therefore, simvastatin possesses antitumor effects that are dependent upon the apoptotic calcium release machinery.

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.

Role of activin-A and myostatin and their signaling pathway in human myometrial and leiomyoma cell function

CONTEXT

Uterine leiomyomas are highly prevalent benign tumors of premenopausal women and the most common indication for hysterectomy. However, the exact etiology of this tumor is not fully understood.

OBJECTIVE

The objective of the study was to evaluate the role of activin-A and myostatin and their signaling pathways in human myometrial and leiomyoma cells.

DESIGN

This was a laboratory study.

SETTING

Myometrial and leiomyoma cells (primary and cell lines) were cultured in vitro.

PATIENTS

The study included premenopausal women who were admitted to the hospital for myomectomy or hysterectomy.

INTERVENTIONS

Primary myometrial and leiomyoma cells and/or cell lines were treated with activin-A (4 nM) and myostatin (4 nM) for different days of interval (to measure proliferation rate) or 30 minutes (to measure signaling molecules) or 48 hours to measure proliferating markers, extracellular matrix mRNA, and/or protein expression by real-time PCR, Western blot, and/or immunocytochemistry.

RESULTS

We found that activin-A and myostatin significantly reduce cell proliferation in primary myometrial cells but not in leiomyoma cells as measured by a CyQUANT cell proliferation assay kit. Reduced expression of proliferating cell nuclear antigen and Ki-67 were also observed in myometrial cells in response to activin-A and myostatin treatment. Activin-A also significantly increased mRNA expression of fibronectin, collagen1A1, and versican in primary leiomyoma cells. Finally, we found that activin-A and myostatin activate Smad-2/3 signaling but do not affect ERK or p38 signaling in both myometrial and leiomyoma cells.

CONCLUSIONS

This study results suggest that activin-A and myostatin can exert antiproliferative and/or fibrotic effects on these cell types via Smad-2/3 signaling.

MicroRNAs in the development and pathobiology of uterine leiomyomata: does evidence support future strategies for clinical intervention?

BACKGROUND

Human leiomyomata (fibroids) are benign tumors of the uterus, represent the most common neoplasms of reproductive-aged women and have a prevalence of ∼70% in the general population. This disorder conveys a significant degree of morbidity and remains the leading indication for hysterectomy in the USA. Prior investigations of aberrant microRNA (miRNA) expression in various malignancies have provided invaluable insight into the role of this class of small non-coding RNAs in tumor growth. Evidence of irregular miRNA expression in uterine fibroids has garnered recent interest for diagnostic and therapeutic applications. Since miRNA gene targets modulate several processes implicated in the genesis of uterine fibroids, more focused investigation has the potential to elucidate the functional significance of miRNA in the genesis and pathology of the disease.

METHODS

Comprehensive electronic searches of peer reviewed published literature in PubMed (US National Library of Medicine, National Institute of Health; http://www.ncbi.nlm.nih.gov/pubmed/) were performed for content related to the biologic functions of miRNA, the roles of miRNA in human disease and studies investigating miRNA in the context of uterine leiomyomata. Herein, this article will review the current evidence supporting the use of miRNA expression profiling as an investigative tool to assess the pathobiology of uterine fibroids and will discuss potential future applications of miRNAs as biomarkers and therapeutic targets.

RESULTS

Mounting evidence supports a functional role for miRNA as either indirect or direct regulators of gene expression which impacts the pathobiology of uterine fibroids. Specifically, miRNAs let-7, 200a, 200c, 93, 106b and 21 have been implicated in cellular proliferation, apoptosis, extracellular matrix turnover, angiogenesis and inflammation. Preliminary data provide evidence to suggest that respective in vitro miRNA expression in leiomyomata and myometrium is regulated by sex steroids.

CONCLUSIONS

Collectively, the identification of aberrantly expressed miRNAs in uterine leiomyomata and accumulating data derived from mining of gene target prediction models and recent functional studies support the concept that miRNAs might impact the genesis and progression of disease. However, the specific biologic functions of differential miRNA expression have yet to be confirmed in vivo. Further functional studies and developing miRNA technology may provide the basis for future applications of miRNAs in clinical medicine as biomarkers and therapeutic targets.

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.

1,25-dihydroxyvitamin d3 reduces extracellular matrix-associated protein expression in human uterine fibroid cells

Uterine fibroids (leiomyomas) are the most common benign tumors associated with excessive deposition of extracellular matrix (ECM)-associated proteins that increase fibroid tumorigenicity. Herein, we determined the expression levels of vitamin D receptor (VDR) protein in human uterine fibroids and compared these levels to those in adjacent normal myometrium. Using Western blot analysis, we found that more than 60% of uterine fibroids analyzed (25 of 40) expressed low levels of VDR. We also found that the biologically active 1,25-dihydroxyvitamin D3 (1,25[OH]2D3), which functions via binding to its nuclear VDR, induced VDR in a concentration-dependent manner and reduced ECM-associated fibrotic and proteoglycans expression in immortalized human uterine fibroid cell line (HuLM). At 1-10 nM concentrations, 1,25(OH)2D3 significantly induced (P < 0.05) nuclear VDR, which was further stimulated by higher concentrations of 1,25(OH)2D3 in HuLM cells. 1,25(OH)2D3 at 10 nM also significantly reduced (P < 0.05) the protein expression of ECM-associated collagen type 1, fibronectin, and plasminogen activator inhibitor-1 (PAI-1) in HuLM cells. We also found that 1,25(OH)2D3 reduced mRNA and protein expressions of proteoglycans such as fibromodulin, biglycan, and versican in HuLM cells. Moreover, the aberrant expression of structural smooth muscle actin fibers was reduced by 1,25(OH)2D3 treatment in a concentration-dependent manner in HuLM cells. Taken together, our results suggest that human uterine fibroids express reduced levels of VDR compared to the adjacent normal myometrium and that treatment with 1,25(OH)2D3 can potentially reduce the aberrant expression of major ECM-associated proteins in HuLM cells. Thus, 1,25(OH)2D3 might be an effective, safe, nonsurgical treatment option for human uterine fibroids.

3D in vitro tissue models and their potential for drug screening

INTRODUCTION

The development of one standard, simplified in vitro three-dimensional tissue model suitable to biological and pathological investigation and drug-discovery may not yet be feasible, but standardized models for individual tissues or organs are a possibility. Tissue bioengineering, while concerned with finding methods of restoring functionality in disease, is developing technology that can be miniaturized for high throughput screening (HTS) of putative drugs. Through collaboration between biologists, physicists and engineers, cell-based assays are expanding into the realm of tissue analysis. Accordingly, three-dimensional (3D) micro-organoid systems will play an increasing role in drug testing and therapeutics over the next decade. Nevertheless, important hurdles remain before these models are fully developed for HTS.

AREAS COVERED

We highlight advances in the field of tissue bioengineering aimed at enhancing the success of drug candidates through pre-clinical optimization. We discuss models that are most amenable to high throughput screening with emphasis on detection platforms and data modeling.

EXPERT OPINION

Modeling 3D tissues to mimic in-vivo architecture remains a major challenge. As technology advances to provide novel methods of HTS analysis, so do potential pitfalls associated with such models and methods. We remain hopeful that integration of biofabrication with HTS will significantly reduce attrition rates in drug development.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND

It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology.

METHODS

Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed.

RESULTS

Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms.

CONCLUSIONS

Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroid's abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.

Extracellular matrix collagen alters cell proliferation and cell cycle progression of human uterine leiomyoma smooth muscle cells

Uterine leiomyomas (ULs) are benign tumors occurring in the majority of reproductive aged women. Despite the high prevalence of these tumors, little is known about their etiology. A hallmark of ULs is the excessive deposition of extracellular matrix (ECM), primarily collagens. Collagens are known to modulate cell behavior and function singularly or through interactions with integrins and growth factor-mediated mitogenic pathways. To better understand the pathogenesis of ULs and the role of ECM collagens in their growth, we investigated the interaction of leiomyoma smooth muscle cells (LSMCs) with two different forms of collagen, non-polymerized collagen (monomeric) and polymerized collagen (fibrillar), in the absence or presence of platelet-derived growth factor (PDGF), an abundant growth factor in ULs. Primary cultures of human LSMCS from symptomatic patients were grown on these two different collagen matrices and their morphology, cytoskeletal organization, cellular proliferation, and signaling pathways were evaluated. Our results showed that LSMCs had distinct morphologies on the different collagen matrices and their basal as well as PDGF-stimulated proliferation varied on these matrices. These differences in proliferation were accompanied by changes in cell cycle progression and p21, an inhibitory cell cycle protein. In addition we found alterations in the phosphorylation of focal adhesion kinase, cytoskeletal reorganization, and activation of the mitogen activated protein kinase (MAPK) signaling pathway. In conclusion, our results demonstrate a direct effect of ECM on the proliferation of LSMCs through interplay between the collagen matrix and the PDGF-stimulated MAPK pathway. In addition, these findings will pave the way for identifying novel therapeutic approaches for ULs that target ECM proteins and their signaling pathways in ULs.

Racial and ethnic differences in the pathogenesis and clinical manifestations of uterine leiomyoma

Uterine leiomyomas are the most common benign gynecologic condition. The prevalence is three times more common among women of African ethnicity. Disparity in this disease is evidenced by earlier age of onset, greater severity of symptoms, and different response to treatment. Although the pathogenesis of disease development is not completely known, growing evidence focuses on investigating the molecular mechanisms in disease development and the influence of ethnicity. Variation in the expression levels or function of estrogen and progesterone receptors, polymorphism of genes involved in estrogen synthesis and/or metabolism (COMT, CYP17), retinoic acid nuclear receptors (retinoid acid receptor-α, retinoid X receptor-α), and aberrant expression of micro-RNAs (miRNAs) are some of the molecular mechanisms that may be involved. Nutritional factors, such as vitamin D deficiency, might also contribute to the higher incidence in dark skinned populations who are also commonly suffer from hypovitaminosis D. Culture and environmental difference might have a role in disease development. Further analysis and better understanding of these mechanisms will provide insight into the molecular basis of racial disparities in leiomyoma formation and will help to develop new innovations in leiomyoma treatment.

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.