Hypoxia Induces Hypoxia-Inducible Factor 1α and Potential HIF-Responsive Gene Expression in Uterine Leiomyoma

Hypoxia in uterine fibroids: role in pathobiology and therapeutic opportunities

Uterine fibroids are the most common tumors in females affecting up to 70% of women world-wide, yet targeted therapeutic options are limited. Oxidative stress has recently surfaced as a key driver of fibroid pathogenesis and provides insights into hypoxia-induced cell transformation, extracellular matrix pathophysiology, hypoxic cell signaling cascades, and uterine biology. Hypoxia drives fibroid tumorigenesis through (1) promoting myometrial stem cell proliferation, (2) causing DNA damage propelling transformation of stem cells to tumor initiating cells, and (3) driving excess extracellular matrix (ECM) production. Common fibroid-associated DNA mutations include MED12 mutations, HMGA2 overexpression, and Fumarate hydratase loss of function. Evidence suggests an interaction between hypoxia signaling and these mutations. Fibroid development and growth are promoted by hypoxia-triggered cell signaling via various pathways including HIF-1, TGFβ, and Wnt/β-catenin. Fibroid-associated hypoxia persists due to antioxidant imbalance, ECM accumulation, and growth beyond adequate vascular supply. Current clinically available fibroid treatments do not take advantage of hypoxia-targeting therapies. Growing pre-clinical and clinical studies identify ROS inhibitors, anti-HIF-1 agents, Wnt/β-catenin inhibition, and TGFβ cascade inhibitors as agents that may reduce fibroid development and growth through targeting hypoxia.

Highly Sensitive Cyanine Dyes for Rapid Sensing of NAD(P)H in Mitochondria and First-Instar Larvae of Drosophila melanogaster

We have developed two highly sensitive cyanine dyes, which we refer to as probes A and B. These dyes are capable of quick and sensitive sensing of NAD(P)H. The dyes were fabricated by connecting benzothiazolium and 2,3-dimethylnaphtho[1,2-d]thiazol-3-ium units to 3-quinolinium through a vinyl bond. In the absence of NAD(P)H, both probes have low fluorescence and absorption peaks at 370 and 400 nm, correspondingly. This is because of their two electron-withdrawing acceptor systems with high charge densities. However, when NAD(P)H reduces the probes' electron-withdrawing 3-quinolinium units to electron-donating 1,4-dihydroquinoline units, the probes absorb at 533 and 535 nm and fluoresce at 572 and 586 nm for A and B correspondingly. This creates well-defined donor-π-acceptor cyanine dyes. We successfully used probe A to monitor NAD(P)H levels in live cells during glycolysis, under hypoxic conditions induced by CoCl2 treatment and after treatment with cancer drugs, including cisplatin, camptothecin, and gemcitabine. Probe A was also employed to visualize NAD(P)H in Drosophila melanogaster first-instar larvae. We observed an increase in NAD(P)H levels in A549 cancer cells both under hypoxic conditions and after treatment with cancer drugs, including cisplatin, camptothecin, and gemcitabine.

Pathways of Hypoxia-Inducible Factor (HIF) in the Orchestration of Uterine Fibroids Development

Uterine fibroids (UF) are common benign tumors in women. The course of UF is associated with troubling symptoms and the development of infertility and pregnancy pathology. Surgical treatment even implies hysterectomy, while pharmacological interventions are modestly effective. Classically, hypoxic metabolism is considered a hallmark of malignant tumor. However, the role of hypoxia-induced factor (HIF) is significant in benign tumors as well. Herein, we briefly review the basic biology of HIF-family proteins, outlining their possible roles in UF. Apart from theoretical justifications, we summarized 15 studies reporting increased expression of HIFs and downstream factors in UF samples. Altogether, data suggest that increased expression of the HIF-protein and altered expression of its dependent genes are presumed to be the factors leading to UF development. Thus, even without being a malignant tumor, UF is characterized by the strong involvement of HIF. This novel insight may give rise to further research in the direction of finding new prognostic markers and effective medicines against UF.

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.

HIF-1α is essential for the augmentation of myometrial contractility during labor†

Uterine contraction is crucial for a successful labor and the prevention of postpartum hemorrhage. It is enhanced by hypoxia; however, its underlying mechanisms are yet to be elucidated. In this study, transcriptomes revealed that hypoxia-inducible factor-1alpha was upregulated in laboring myometrial biopsies, while blockade of hypoxia-inducible factor-1alpha decreased the contractility of the myometrium and myocytes in vitro via small interfering RNA and the inhibitor, 2-methoxyestradiol. Chromatin immunoprecipitation sequencing revealed that hypoxia-inducible factor-1alpha directly binds to the genome of contraction-associated proteins: the promoter of Gja1 and Ptgs2, and the intron of Oxtr. Silencing the hypoxia-inducible factor-1alpha reduced the expression of Ptgs2, Gja1, and Oxtr. Furthermore, blockade of Gja1 or Ptgs2 led to a significant decrease in myometrial contractions in the hypoxic tissue model, whereas atosiban did not remarkably influence contractility. Our study demonstrates that hypoxia-inducible factor-1alpha is essential for promoting myometrial contractility under hypoxia by directly targeting Gja1 and Ptgs2, but not Oxtr. These findings help us to better understand the regulation of myometrial contractions under hypoxia and provide a promising strategy for labor management and postpartum hemorrhage treatment.

HIF-1α drives the transcription of NOG to inhibit osteogenic differentiation of periodontal ligament stem cells in response to hypoxia

Osteogenic differentiation of periodontal ligament stem cells (PDLSCs) is limited in hypoxia, and HIF-1α is key to the response to hypoxia. However, its mechanisms remain largely unknown. This study discovered an osteogenesis-related gene sensitive to hypoxia in PDLSCs, and investigated the molecular mechanisms between HIF-1α and the gene. NOG, a gene that negatively regulates osteogenesis, was discovered by RNA-seq. Under normoxic conditions, HIF-1α overexpression led to enhanced expression of NOG/Noggin and inhibited the expression of osteogenesis-related genes, while inhibition of HIF-1α reversed this effect. The expression of HIF-1α, NOG/Noggin and the osteogenesis-related genes were detected by qRT-PCR or Western blot. Mechanistically, we verified that HIF-1α binds to the hypoxia response element (-1505 to -1502) in the promotor of NOG to enhance secretion of Noggin by chromatin immunoprecipitation and a dual-luciferase reporter assay. IHC staining findings in an animal model verified that Noggin-associated osteogenic differentiation was inhibited in hypoxia. NOG displayed a concordant relationship with HIF-1α, and secreted more with increasing of HIF-1α. Hypoxia stabilized HIF-1α, which bound to the HRE (-1505 to -1502) of the NOG promotor to enhance NOG transcription resulted in inhibiting osteogenic differentiation of PDLSCs. This study offers a promising therapy for periodontitis.

ANGPTL4 regulates the osteogenic differentiation of periodontal ligament stem cells

The molecular mechanism of mechanical force regulating the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) has not been clearly elucidated. In this study, two mRNA-seqs, GSE106887 and GSE109167, which contained several samples of PDLSCs under mechanical force, were downloaded from Gene Expression Omnibus. Differential expression analysis was firstly taken between GSE106887 and GSE109167, then the common 84 up-regulated genes and 26 down-regulated genes were selected. Function enrichment analysis was used to identify the key genes and pathways in PDLSCs subjected to the tension and compression force. PDLSCs were isolated from human periodontal ligament tissues. The effects of ANGPTL4 knockdown with shRNA on the osteogenic differentiation of PDLSCs were studied in vitro. Then, the orthodontic tooth movement (OTM) rat model was used to study the expression of HIF-1α and ANGPTL4 in alveolar bone remodeling in vivo. ANGPTL4 and the HIF-1 pathway were identified in PDLSCs subjected to the tension and compression force. alizarin red staining, alcian blue staining, and oil red O staining verified that PDLSCs had the ability of osteogenic, chondrogenic, and adipogenic differentiation, respectively. Verification experiment revealed that the expression of ANGPTL4 in PDLSCs significantly increased when cultured under osteogenic medium in vitro. While ANGPTL4 was knocked down by shRNA, the levels of ALPL, RUNX2, and OCN decreased significantly, as well as the protein levels of COL1A1, ALPL, RUNX2, and OCN. During the OTM, the expression of HIF-1α and ANGPTL4 in periodontal ligament cells increased on the tension and compression sides. We concluded the positive relationship between ANGPTL4 and osteogenic differentiation of PDLSCs.

Oviductal Oxygen Homeostasis in Patients with Uterine Myoma: Correlation between Hypoxia and Telocytes

Oxygen balance is crucial for angiogenesis, immunity, and tissue repair. The human oviduct is essential for reproductive function, and any imbalance in homeostasis leads to fertility disturbances and might be a reason for ectopic pregnancy development. Uterine myoma is a widespread benign tumour, which is often accompanied by infertility. Telocytes have been discussed in the contexts of motility, fibrosis development, and angiogenesis. We observed the oviducts from patients with and without uterine myoma, comparing the expression of HIF-1, HO, VEGF and its receptor, NOS, oestrogen, and progesterone receptors by immunolabeling. The myometrial and oviductal telocytes were also compared in both groups. Biochemical analyses were conducted for FSH, LH, AMH, sFlt, oestrogen, and progesterone in blood samples. Patients with uterine myoma have different expressions of sex steroid receptors and an increased number of telocytes. The decreasing VEFG expression was compensated by the rise in the HIF-1 and NOS expression. Blood biochemical analyses revealed a higher progesterone level and lower AMH in patients with uterine myoma. No differences in sFlt, FSH, and LF were observed. Uterine myoma impacts oviduct oxygen homeostasis and might cause fertility disturbances (uterine and oviductal infertility factors).

Antitumor effect of the selective hypoxia-inducible factor-1 inhibitors echinomycin and PX-478 on uterine fibroids

OBJECTIVE

To investigate the antitumor effects of the selective hypoxia-inducible factor-1 (HIF-1) inhibitors echinomycin and PX-478 on uterine fibroids.

DESIGN

Experimental study using in vitro primary culture systems and an in vivo mouse xenograft model.

SETTING

Academic university center.

PATIENT(S)

Women with uterine fibroids who underwent hysterectomy or myomectomy.

INTERVENTION(S)

Administration of the selective HIF-1 inhibitors echinomycin and PX-478 to the media of the primary cultured uterine fibroid cells and to nonobese diabetic/severe combined immunodeficient mice bearing fibroid xenografts consisting of the primary cultured fibroid cells and type Ⅰ collagen gels beneath the kidney capsule.

MAIN OUTCOME MEASURE(S)

Cell proliferation was measured by Cell Counting Kit-8 assay. Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay and by measuring caspase 3 and 7 activities. The xenografts were evaluated by gross appearance, surface area, and histology. The Ki-67 index was measured to evaluate proliferation of the xenografts.

RESULT(S)

Both echinomycin and PX-478 inhibited cell proliferation and induced apoptosis in fibroid cells cultured under hypoxia and normoxia. Enlargement of the fibroid xenografts was significantly attenuated. The Ki-67 index significantly decreased after the administration of the HIF-1 inhibitors in the xenograft model. Eight of 27 xenografts treated with the HIF-1 inhibitors contained calcification and hyalinizing components from 3 days after the grafting to 2 weeks, suggesting that the HIF-inhibitors induce degeneration of the fibroid xenografts.

CONCLUSION(S)

The selective HIF-1 inhibitors echinomycin and PX-478 show antitumor effects against uterine fibroids both in vitro and in vivo. These findings support the potential use of HIF-1 inhibitors for the treatment of uterine fibroids.

The role of fructose 1,6-bisphosphate-mediated glycolysis/gluconeogenesis genes in cancer prognosis

Metabolic reprogramming and elevated glycolysis levels are associated with tumor progression. However, despite cancer cells selectively inhibiting or expressing certain metabolic enzymes, it is unclear whether differences in gene profiles influence patient outcomes. Therefore, identifying the differences in enzyme action may facilitate discovery of gene ontology variations to characterize tumors. Fructose-1,6-bisphosphate (F-1,6-BP) is an important intermediate in glucose metabolism, particularly in cancer. Gluconeogenesis and glycolysis require fructose-1,6-bisphosphonates 1 (FBP1) and fructose-bisphosphate aldolase A (ALDOA), which participate in F-1,6-BP conversion. Increased expression of ALDOA and decreased expression of FBP1 are associated with the progression of various forms of cancer in humans. However, the exact molecular mechanism by which ALDOA and FBP1 are involved in the switching of F-1,6-BP is not yet known. As a result of their pancancer pattern, the relationship between ALDOA and FBP1 in patient prognosis is reversed, particularly in lung adenocarcinoma (LUAD) and liver hepatocellular carcinoma (LIHC). Using The Cancer Genome Atlas (TCGA), we observed that FBP1 expression was low in patients with LUAD and LIHC tumors, which was distinct from ALDOA. A similar trend was observed in the analysis of Cancer Cell Line Encyclopedia (CCLE) datasets. By dissecting downstream networks and possible upstream regulators, using ALDOA and FBP1 as the core, we identified common signatures and interaction events regulated by ALDOA and FBP1. Notably, the identified effectors dominated by ALDOA or FBP1 were distributed in opposite patterns and can be considered independent prognostic indicators for patients with LUAD and LIHC. Therefore, uncovering the effectors between ALDOA and FBP1 will lead to novel therapeutic strategies for cancer patients.

Differential response to hypoxia in leiomyoma and myometrial cells

AIMS

Recent evidence suggests that repetitive hypoxia occurs during menstrual cycles due to vasoconstriction and myometrial contraction. It is unknown if hypoxia contributes to the development of uterine leiomyoma, the most common tumor of the female reproductive system. This study aims to characterize the response to hypoxia in leiomyoma and myometrial cells; and determine if an aberrant leiomyoma response to hypoxia may contribute to leiomyomatogenesis.

MAIN METHODS

Primary and immortalized leiomyoma and myometrial cells were cultured under normoxic and hypoxic conditions. Expression levels of vascular endothelial growth factor-A (VEGF-A), adrenomedullin (ADM), endothelin-1 (ET-1), and hypoxia-inducible factor-1 alpha (HIF-1α) were measured by qRT-PCR, western blotting and ELISA. Cell proliferation was assessed using MTT assay and proliferating-cell-nuclear-antigen (PCNA) expression. KC7F2 (HIF-1α inhibitor) was used to examine the regulating mechanisms.

KEY FINDINGS

As expected, hypoxia induced HIF-1α expression in both leiomyoma and myometrial cells. However, hypoxia induced VEGF-A, ET-1 and ADM expression and VEGF-A secretion into the culture media in leiomyoma but not myometrial cells. MTT assay and PCNA expression showed that hypoxia induces proliferation in leiomyoma, but not myometrial cells. HIF-1α inhibitor abrogated the hypoxia-induced VEGF-A, ET-1, ADM, and PCNA expression in leiomyoma cells.

SIGNIFICANCE

This study suggests an aberrant leiomyoma cellular response to hypoxia compared to myometrium. This differential response to menstruation-related repetitive hypoxia episodes may lead to selective proliferation of hypoxia-adaptive leiomyoma cells and contribute to leiomyoma growth. Thus, in addition to adding to our understanding of leiomyoma pathobiology, the study proposes angiogenic factors as a potential leiomyoma therapeutic target.

Dl-3-N-Butylphthalide Attenuates Hypoxic Injury of Neural Stem Cells by Increasing Hypoxia-Inducible Factor-1alpha

OBJECTIVE

To assess the potential effect of dl-3-N-butylphthalide (dl-NBP) for the proliferation and differentiation of neural stem cells (NSCs) against hypoxia and the underlying mechanism.

MATERIALS AND METHODS

Hippocampal NSCs were obtained from fetal rats. NSCs combined with dl-NBP and single NSCs were cultured. The impact of siRNA-mediated hypoxia-inducible factor-1alpha (HIF-1α) knockdown on NSCs was detected with western blotting (WB) and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). Cell-counting kit-8 assay was used for evaluating the viability of NSCs. Levels of HIF-1α protein were measured using WB, and vascular endothelial growth factor (VEGF) expression was quantified using RT-qPCR and enzyme-linked immunosorbent assay.

RESULTS

Compared with 7 different concentrations of dl-NBP, 0.25 g/L was determined as the optimal concentration to significantly increase the viability of NSCs (p < 0.001). Dl-NBP can significantly increase the viability of hypoxic NSCs (p < 0.001) and improve the differentiation of hypoxic NSCs into astrocytes (p = 0.001) and oligodendrocytes (p < 0.001). Meanwhile, Dl-NBP can significantly elevate levels of HIF-1α protein (p < 0.001) and VEGF mRNA (p = 0.001) / protein (p < 0.001) in NSCs in the hypoxic environment. However, after transfection with HIF-1α siRNA in NSCs, the viability and differentiation of NSCs was not recovered using dl-NBP under the hypoxic condition, as well as levels of HIF-1α and VEGF.

CONCLUSION

Dl-NBP can reverse the weaker proliferation and differentiation power of NSCs in the hypoxic environment. The HIF-1α - VEGF pathway may be implicated in this protective effect of dl-NBP.

Pathogenesis, diagnosis and treatment of uterine lipoleiomyoma: A review

Uterine lipoleiomyomas are variants of uterine leiomyomas and are characterized by progressive enlargement that can occur even after menopause. These tumors can produce serious clinical symptoms and are difficult to diagnosis preoperatively. The growth rate of uterine lipoleiomyomas after menopause is comparatively higher than that of conventional uterine leiomyomas, and lipoleiomyosarcomas as well as tumor-to-tumor metastasis associated with lipoleiomyomas have been reported. However, detailed histogenic mechanisms of the tumor remain unclear. Surgical treatments are the current choice for the management of lipoleiomyomas. The purpose of this review is to promote greater awareness of lipoleiomyoma characteristics with a focus on histogenesis, diagnosis, and treatment. We performed an exhaustive literature review and have summarized the available data. We assessed the interpretation of auxiliary examinations to help physicians in making an early accurate diagnosis of the disease and to help with treatment decision-making, particularly regarding whether surgery should be performed or avoided.

Vascular biology of uterine fibroids: connecting fibroids and vascular disorders

Fibroids are benign tumors caused by the proliferation of myometrial smooth muscle cells in the uterus that can lead to symptoms such as abdominal pain, constipation, urinary retention, and infertility. While traditionally thought of as a disease process intrinsic to the uterus, accumulating evidence suggests that fibroid growth may be linked with the systemic vasculature system, although cell-intrinsic factors are certainly of principal importance in their inception. Fibroids are associated with essential hypertension and preeclampsia, as well as atherosclerosis, for reasons that are becoming increasingly elucidated. Factors such as the renin-angiotensin-aldosterone system, estrogen, and endothelial dysfunction all likely play a role in fibroid pathogenesis. In this review, we lay out a framework for reconceptualizing fibroids as a systemic vascular disorder, and discuss how pharmaceutical agents and other interventions targeting the vasculature may aid in the novel treatment of fibroids.

Characteristics of Tibetan pig lung tissue in response to a hypoxic environment on the Qinghai-Tibet Plateau

To adapt to the plateau environment, Tibetan pigs' lungs have developed a unique physiological mechanism during evolution. The vascular corrosion casting technique and scanning electron microscopy were used to understand arterial architecture. Blood physiological index and quantitative real-time PCR (qRT-PCR) were used for assessing whether the lung can regulate the body through anatomical, physiological and molecular mechanisms to adapt to hypoxic environments. Our study showed that the lungs of Tibetan pigs were heavier and wider and that the pulmonary arteries were thicker and branched and had a denser vascular network than those of Landrace pigs. The hemoglobin (HGB), mean corpuscular hemoglobin concentration (MCHC) values of high-altitude pigs were significantly higher than those of low-altitude pigs. The expression levels of HIF- 1α , EPAS1, EPO and VEGF, but not those of eNOSand EGLN1, were significantly higher in the lungs of high-altitude pigs than in those from pigs at a lower altitude ( P<0.05 ). These findings and a comprehensive analysis help elucidate the pulmonary mechanism of hypoxic adaptation in pigs.

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.

Cartilage Targets of Knee Osteoarthritis Shared by Both Genders

As the leading cause of disability, osteoarthritis (OA) affects people of all ages, sexes, and races. With the increasing understanding of OA, the sex differences have attracted specific attention as the burden of OA is greater in women. There is no doubt that gender-specific OA management has great potential for precision treatment. On the other hand, from the marketing aspect, a medication targeting the OA-responsive biomarker(s) shared by both genders is more favorable for drug development. Thus, in the current study, a published transcriptome dataset of knee articular cartilage was used to compare OA and healthy samples for identifying the genes with the same significantly different expression trend in both males and females. With 128 genes upregulated and 143 genes downregulated in both OA males and females, 9 KEGG pathways have been enriched based on the current knowledge, including 'renal cell carcinoma,' 'ECM-receptor interaction,' 'HIF-1 signaling pathway,' 'MicroRNAs in cancer,' 'focal adhesion,' 'Relaxin signaling pathway,' 'breast cancer,' 'PI3K-Akt signaling pathway,' and 'human papillomavirus infection.' Here, we explore the potential impacts of these clusters in OA. We also analyze the identified 'cell plasma membrane related genes' in-depth to identify the potential chondrocyte cell surface target(s) of OA management.

Autophagy up-regulation by ulipristal acetate as a novel target mechanism in the treatment of uterine leiomyoma: an in vitro study

OBJECTIVE

To assess the effect of ulipristal acetate (UPA) on the autophagic process of uterine leiomyoma cells.

DESIGN

In vitro study in primary cultures of leiomyoma and myometrial cells isolated from biopsy specimen, and gene expression evaluation in biopsy material.

SETTING

Cellular pathology laboratory.

PATIENT(S)

Premenopausal women (without hormonal treatment) undergoing myomectomy or hysterectomy for symptomatic leiomyomas.

INTERVENTION(S)

Surgical specimens collected from uterine leiomyomas and matched normal myometria.

MAIN OUTCOME MEASURE(S)

After treatment of myometrial and leiomyoma cells with UPA, autophagy was evaluated by Western blot analysis of the typical biochemical markers, LC3-II, LC3-II:LC3-I ratio, and p62/SQSTM1. The expression level of Atg7 and Atg4D proteins was also assessed by Western blot.

RESULT(S)

The increase of LC3-II protein, LC3-II:LC3-I ratio, and p62/SQSTM1 protein indicates that UPA treatment up-regulates the autophagic response in leiomyoma cells, whereas these markers were almost unchanged in myometrial cells. Consistently, an increased level of Atg7 and Atg4D proteins was observed only in UPA-treated leiomyoma cells. The autophagic machinery is put into motion selectively in these cells, despite that the basal messenger RNA levels of LC3, SQSTM1, and ATG7 in leiomyoma biopsy specimen were not significantly different from those found in normal myometrial biopsy material.

CONCLUSION(S)

In vitro UPA treatment stimulates the autophagic response selectively in leiomyoma cells, which adds a novel indication for the clinical use of this selective P receptor (PR) modulator. Autophagy up-regulation may potentially contribute to the leiomyoma shrinkage occurring in UPA-treated patients and warrants further study.

TSGA10 overexpression inhibits angiogenesis of HUVECs: A HIF-2α biased perspective

Testis-specific gene antigen 10 (TSGA10) is a protein overexpressed in most cancers; except for some certain types where its expression is reduced. TSGA10 overexpression in HeLa cells has been shown to disrupt hypoxia inducible factor-1α (HIF-1α) axis and exert potent inhibitory effects. Since HIF-1α is structurally and biochemically similar to HIF-2α, TSGA10 is expected to bind HIF-2α and inhibit its function as well. This study elucidated that increased expression of TSGA10 in manipulated human umbilical vein endothelial cells (HUVECs) decreased the proliferation and migration of these cells as affirmed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and wound healing tests, respectively. It also inhibited in vitro angiogenesis of these cells in 3D collagen-cytodex model. Expression levels of genes controlled by HIF-2α including autocrine vascular endothelial growth factor (VEGF) were also assessed using real-time PCR. Our bioinformatic analysis also showed that TSGA10 could bind HIF-2α. Moreover, flow cytometry results indicated a cell cycle arrest in G2/M. Therefore, this study showed that overexpression of TSGA10, as a tumor suppressor gene, in endothelial cells resulted in decreased proliferation, migration and therefore, angiogenic activity of HUVECs. Since angiogenesis is vital for tumor development and metastasis, our findings could be of clinical significance in cancer therapy.