mTor Inhibitors for the Treatment of Endometriosis

The "Road" to Malignant Transformation from Endometriosis to Endometriosis-Associated Ovarian Cancers (EAOCs): An mTOR-Centred Review

Ovarian cancer is an umbrella term covering a number of distinct subtypes. Endometrioid and clear-cell ovarian carcinoma are endometriosis-associated ovarian cancers (EAOCs) frequently arising from ectopic endometrium in the ovary. The mechanistic target of rapamycin (mTOR) is a crucial regulator of cellular homeostasis and is dysregulated in both endometriosis and endometriosis-associated ovarian cancer, potentially favouring carcinogenesis across a spectrum from benign disease with cancer-like characteristics, through an atypical phase, to frank malignancy. In this review, we focus on mTOR dysregulation in endometriosis and EAOCs, investigating cancer driver gene mutations and their potential interaction with the mTOR pathway. Additionally, we explore the complex pathogenesis of transformation, considering environmental, hormonal, and epigenetic factors. We then discuss postmenopausal endometriosis pathogenesis and propensity for malignant transformation. Finally, we summarize the current advancements in mTOR-targeted therapeutics for endometriosis and EAOCs.

EPHA3 enhances macrophage autophagy and apoptosis by disrupting the mTOR signaling pathway in mice with endometriosis

Background: Endometriosis is a chronic fibrotic disease characterized by agonizing pelvic pain and low fertility, mainly affecting middle-aged women. The aim of the present study is to assess the potential effects of erythropoietin-producing hepatocellular carcinoma A3 (EPHA3) on endometriosis, with emphasis on the autophagy and apoptosis of macrophages via inhibition of the mammalian target of rapamycin (mTOR) signaling pathway.

Methods: The mouse models of endometriosis were established followed by culturing the macrophages and macrophage transfection via the EPHA3 vector, siRNA EPHA3, and RAPA (an inhibitor of the mTOR signaling pathway). The expression of EPHA3, related factors in the mTOR signaling pathway, macrophage autophagy (autophagy-related gene 3 (Atg3), light chain 3-I (LC3-I), light chain 3-II (LC3-II) and Beclin1) and apoptosis (B-cell lymphoma-2 (bcl-2), bax and fas) were all detected and documented, respectively. The changes of autophagic lysosomes and the apoptosis of macrophages in each group following transfection were also inspected and detected.

Results: The results of the in silico analysis ascertained EPHA3 to be a candidate gene of endometriosis. After successful modeling, the uterine tissues of endometriosis mice presented with a low expression of EPHA3 and activated mTOR signaling pathway. Overexpression of EPHA3 inhibited the activation of the mTOR signaling pathway, down-regulated bcl-2 expression, up-regulated the expression of Atg3, LC3-II/LC3-I, Beclin1, bax and fas, and also promoted the autophagy and apoptosis of macrophages in endometriosis mice.

Conclusion: Altogether, EPHA3 could potentially promote the autophagy and apoptosis of macrophages in endometriosis via inhibition of the mTOR signaling pathway, highlighting the potential of EPHA3 as the target to treat endometriosis.

Overexpression of TGF-β enhances the migration and invasive ability of ectopic endometrial cells via ERK/MAPK signaling pathway

Endometriosis is a common gynecological disease with manifestations of endometrial-like tissue outside the uterus. Transforming growth factor-β (TGF-β) is known to facilitate a series of biological events in many cells, including migration. However, the roles of TGF-β in endometriosis still remain largely unknown. The aim of the present study was to discover the role of TGF-β1 in endometriosis development and progression and its associated mechanisms. It was demonstrated that the expression of TGF-β1 was significantly elevated in endometriosis in comparison with that in normal tissue. Overexpression of TGF-β increased the proliferation and upregulated proliferating cell nuclear antigen and cyclin D1 in endometrial stromal cells (ESCs). Furthermore, TGF-β overexpression also triggered a series of biological events occurring in ESCs, including cell migration and invasion, and activated the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling pathway. The inhibition of the ERK/MAPK pathway reversed the previous effects of TGF-β overexpression. Collectively, the present results indicate that overexpression of TGF-β enhances the migration and invasion of ectopic ESCs via the ERK/MAPK signaling pathway, providing theoretical evidence for the development of new treatment methods targeting the TGF-β-ERK/MAPK signaling pathway for prophylaxis of endometriosis.

Standards Used by a Clinical and Scientific Endometriosis Center for the Diagnosis and Therapy of Patients with Endometriosis

Endometriosis is one of the most common benign gynecological diseases. The extremely heterogeneous complex of symptoms complicates the diagnosis and treatment of this disease. In most patients, there is a latency period of several years between the first occurrence of symptoms and the definitive diagnosis. This paper aims (1) to evaluate standards for the diagnosis and treatment of patients with (symptoms suspicious for) endometriosis in terms of feasibility, and (2) to assess the potential use of data collected by a certified clinical and scientific endometriosis center to answer scientific questions. Standards for outpatient consultations were developed for a special endometriosis outpatient clinic. Between January 2014 and December 2017, a total of 1715 outpatients with a suspicion of endometriosis presented to this special endometriosis outpatient clinic; the diagnosis and treatment of patients was carried out in accordance with the developed standards. Data of this patient cohort obtained from patient records created during outpatient consultations and from a questionnaire recorded in an Oracle-based database was analyzed. The patient cohort was also compared with another patient cohort who had attended different outpatient clinics and had been diagnosed intraoperatively with endometriosis. 41.8% of patients examined during special outpatient consultations had surgery for suspicion or recurrence of endometriosis. Endometriosis was confirmed in 81.5% of cases. Pain symptoms were the main indication for surgery in 70.1% of cases compared to 45.1% of cases in the comparison group. The structured approach used in the special endometriosis outpatient clinic is a key aspect of the care provided by the certified clinical and scientific endometriosis center. It ensures that patients are diagnosed and treated in accordance with guideline recommendations, that diagnosis and treatment comply with certification requirements, and that the collected data can be used to answer scientific questions.

Investigational drugs for the treatment of endometriosis, an update on recent developments

INTRODUCTION

Endometriosis is a hormone-dependent benign chronic disease that requires a chronic medical therapy. Although currently available drugs are efficacious in treating endometriosis-related pain, some women experience partial or no improvement. Moreover, the recurrence of symptoms is expected after discontinuation of the therapies. Currently, new drugs are under intense clinical investigation for the treatment of endometriosis.

AREAS COVERED

This review aims to offer the reader a complete and updated overview on new investigational drugs and early molecular targets for the treatment of endometriosis. The authors describe the pre-clinical and clinical development of these agents.

EXPERT OPINION

Among the drugs under investigation, late clinical trials on gonadotropin-releasing hormone antagonists (GnRH-ant) showed the most promising results for the treatment of endometriosis. Aromatase inhibitors (AIs) are efficacious in treating endometriosis related pain symptoms but they cause significant adverse effects that limit their long-term use. New targets have been identified to produce drugs for the treatment of endometriosis, but the majority of these new compounds have only been investigated in laboratory studies or early clinical trials. Thus, further clinical research is required in order to elucidate their efficacy and safety in human.