CC BY-NC-ND 4.0 · Geburtshilfe Frauenheilkd 2024; 84(06): 555-563
DOI: 10.1055/a-2306-8759
GebFra Science
Review

The Hallmarks of Endometriosis

Markenzeichen von Endometriose
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
,
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
,
Katharina Au
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
,
Louisa Hofbeck
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
,
Lisa Windischbauer
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
,
Laura Lotz
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
,
Matthias W. Beckmann
1   Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany (Ringgold ID: RIN27168)
› Author Affiliations
 

Abstract

A heuristic tool called “the hallmarks of cancer” helps to reduce the enormous complexity of cancer phenotypes and genotypes to a preliminary set of guiding principles. Other aspects of cancer have surfaced as possible improvements in our understanding of the disease’s mechanisms. Endometriosis is a gynecological disease condition negatively impacting the quality of life of many women. To date, there is no curative treatment for endometriosis. Therapy is aimed at treating the symptoms using hormone therapy, pain therapy and complementary therapy. Chronic pain and overlapping pain syndromes and illnesses can also be treated with multimodal pain therapy and psychosomatic therapy. Endometriosis is, however, a chronic and complex entity which, in this regard, resembles cancer. The present work investigates the hallmarks of endometriosis with a view to summarizing the current research status and paving new ways for future research projects.


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Zusammenfassung

Ein heuristisches Werkzeug, „Markenzeichen von Krebs“ genannt, wird eingesetzt, um die große Komplexität der Phänotypen und Genotypen von Krebszellen zu vereinfachen und in einer vorläufigen Reihe von Leitprinzipien zusammenzufassen. Andere Aspekte von Krebserkrankungen sind in jüngster Zeit auch als potenzielle Ansätze zur Verbesserung des Verständnisses von Krebserkrankungsmechanismen in Erscheinung getretten. Die Endometriose ist eine gynäkologische Erkrankung, welche die Lebensqualität vieler Frauen stark beeinträchtigt. Es gibt bisher keine kurative Behandlung dafür. Die aktuellen Therapien fokussieren darauf, Symptome anhand von Hormontherapie, Schmerztherapie sowie komplementären Therapien zu lindern. Chronische Schmerzen und überlappende Schmerzsyndrome und Erkrankungen können mithilfe multimodaler Schmerztherapien und psychosomatischer Therapien behandelt werden. Aber die Endometriose ist eine chronische und komplexe Entität, die Ähnlichkeiten mit Krebs aufweist. Diese Arbeit untersucht die Kennzeichen von Endometriose mit dem Ziel, den aktuellen Forschungsstand zusammenzufassen und neue Wege für künftige Forschungsprojekte zu ebnen.


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Introduction

Endometriosis classification

Endometriosis describes a disease characterized by the colonization of endometrium-like lesions outside the uterine cavity. Ectopic lesions were thought to represent solely lesions on the peritoneum of the internal genital organs (endometriosis genitalis externa), but in the meantime a migration of endometrial-like cells into the myometrium has been also described, hence rendering adenomyosis uteri (= endometriosis genitalis interna) a distinct disease entity. However, since endometriotic lesions may also infiltrate deeply into organs (mostly bowel, bladder or ureter) (deep infiltrating endometriosis) or even spread to the diaphragm or the umbilicus (extragenital endometriosis), symptoms are often extremely complicated [1]. A clinical/intraoperative distinction is made between the following four major entities of endometriosis depending on localization and extent: superficial, ovarian, uterine and deep infiltrating endometriosis. Deep infiltrating endometriotic lesions exceed the surface (usually the peritoneum) and invade into neighboring tissue or organs with an infiltration depth of at least 0.5 cm ([Fig. 1]) [2] [3]. The most widely used clinical/intraoperative classification is the rASRM score, the revised classification of the American Society for Reproductive Medicine (formerly the American Fertility Society) [2] [4]. The rASRM score describes peritoneal and ovarian endometriosis. Deep endometriosis is included in the calculation of the numerical value, but no mapping or classification can be derived from it. To remedy this deficiency, a German-speaking working group has developed the Enzian classification. This classifies deep lesions in 3 anatomical levels or compartments (A: rectovaginal septum/vagina, B: sacrouterine ligament/pelvic wall, C: rectum). #Enzian represents since 2021 a novel comprehensive classification that included the superficial endometriosis, ovarian and with the Enzian classification, hence constituting a more rounded classification system, which, nevertheless, does not incorporate the two major symptoms of endometriosis: pain and infertility [5].

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Fig. 1 Deep infiltrating endometriosis-Intraoperative laparoscopic views (Patient collective-Department of Gynecology, University Hospital of Erlangen).

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Symptoms and diagnosis

Diagnosis of endometriosis is based on a detailed medical history, a thorough gynecological clinical examination including vaginal and rectovaginal or rectal palpation, a transvaginal and/or even transrectal sonographic evaluation, a renal ultrasonography with a view to ruling out asymptomatic urinary retention caused by deep infiltrating endometriosis of the ureter, magnetic resonance imaging, as well as a histological examination [6] [7] [8]. The diagnosis of a deep infiltrating endometriosis is mainly clinical – by describing the clinical symptoms (although not specific), inspection with two-leaf specula and vaginal and rectal palpation. Vaginal sonography should be performed first as an imaging measure, not least because of the simultaneous possibility of identifying ovarian endometriomas. Furthermore, deep rectal infiltration can be easily diagnosed by an experienced physician. If rectal endometriosis is suspected, an endosonography and/or colorectoscopy is often automatically arranged. However, endometrial infiltration of the mucosa is rather rare. A colorectoscopy should be performed in the presence of intestinal bleeding and whenever a bowel resection is intended in the case of suspected bowel infestation in order to rule out primary bowel pathologies such as polyps, tumors or inflammatory bowel diseases [9]. [Fig. 2] summarizes the possible diagnostic approaches based on the four major endometriosis entities. Taken altogether, endometriosis genitalis (including vaginal endometriosis) is mainly associated with dysmenorrhea and dyspareunia, deep infiltrating endometriosis correlates with dysuria and dyschezia, while extragenital endometriosis (in organs other than the bladder or the bowel) requires a symptom-oriented examination [6] [7] [8] [9] [10]. Importantly, superficial peritoneal endometriosis might remain obscure until the performance of a diagnostic laparoscopy.

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Fig. 2 Diagnostic approaches based on the four major endometriotic entities.

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Current therapeutic standards

Conservative options include medical and complementary procedures, reproductive medicine measures as well as multimodal pain management models (i.e. heat application, physical exercises, etc.) and psychotherapy in the wider context of the bio-psycho-social model. Surgical options include organ-preserving or radical and, if necessary, interdisciplinary ablation or excision of endometriosis lesions, preferably in certified endometriosis facilities [11]. Established pharmacologic approaches include either analgesics from the group of non-steroidal anti-inflammatory drugs (NSAIDs) or hormone therapy. NSAIDs pursue a symptomatic therapeutic approach [12]. As non-hormonal options treat purely symptomatically, hormone therapy is generally used. Established hormonal options include progesterons in the first-line therapy, as well as oral contraceptives and Gonadotropin-Releasing Hormone (GnRH) (ant-)agonists in the second-line therapy. There are no objectifiable differences with regard to the reduction of typical pain symptoms. There are differences in terms of undesirable side effects, the duration of possible use and the costs. Drug therapy is only effective while it is being taken, after which symptoms may recur immediately [13]. Progestogens (especially dienogest 2 mg) are the options for first-line therapy. They produce hypoestrogenism through anovulation. In oral contraceptives, they are part of a fixed combination of ethinylestradiol or estradiol valerate. When selecting progestogen, secondary treatment goals such as the treatment of skin blemishes can also be taken into account. Long-cycle use is more effective than cyclical use in reducing symptoms typical of endometriosis and should be favored [11] [13] [14] [15].


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Hallmarks of Endometriosis

Over the past years, the scientific community has been able to investigate different molecular pathways and gain an insight into the (epi-)genetic and/or cellular mechanisms that seem to play a significant role in the genesis and progression of endometriosis. Of utmost significance, these pathomechanisms seem to pave new ways in the context of endometriosis diagnosis (as biomarkers) and therapy (as drug targets). The (epi-)genetic mechanisms are involved in the immunologic, immunohistochemical, histological, and biological aberrations of endometriosis [16]. Pelvic endometriosis has a complex pathogenesis and pathophysiological features. Two possible causes of the endometriotic lesions are in situ coelomic metaplasia of the peritoneal lining and transplantation of endometrial tissue through retrograde menstruation. In cases of extrapelvic lesions, vascular or lymphatic metastasis most likely happens infrequently. Through interacting molecular mechanisms that support cellular adhesion and proliferation, systemic and localized steroidogenesis, localized inflammatory response and immune dysregulation, as well as vascularization and innervation, superficial and deep endometriotic lesions seem to be established and maintained [17]. Endometriosis-related signaling pathways included estrogen-2, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), mitogen-activated protein kinase (MAPK), extracellular-signal regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB/AKT) and mechanistic target of rapamycin (mTOR) (PAM), yes-associated protein (YAP), Wnt/β-catenin, Rho-associated protein kinase (ROCK), transforming growth factor β (TGF-β), vascular endothelial growth factor (VEGF), nitric oxide (NO), iron, cytokines and chemokines [18]. Despite being a benign condition, endometriosis exhibits malignant traits such as metastasis, hyperplasia, and cell invasion. This suggests a possible connection between endometriosis and particular signaling molecules and pathways that influence the invasion and metastasis of numerous common malignancies. The six biological abilities that are acquired throughout the multi-step development of human tumors are the hallmarks of cancer. The defining multiple characteristics provide a framework for understanding the complexity of neoplastic disease. The ability to maintain proliferative signaling, avoid growth suppressors, withstand cellular death, permit replicative immortality, trigger angiogenesis, and initiate invasion and metastasis are a few of them. These hallmarks are underpinned by inflammation, which supports several hallmark functions, and genome instability, which produces the genetic diversity that speeds up their acquisition. Two newer hallmarks of potential generality include reprogramming of energy metabolism and immune escape [19]. In this regard, [Fig. 3] summarizes the corresponding hallmarks of endometriosis.

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Fig. 3 Hallmarks of endometriosis and their potential targets for therapy. Captions in blue: completed clinical trials. Captions in green: ongoing clinical trials. Captions in black: experimental models in vitro/in vivo. Abbreviations: ADAM17 = A Disintegrin and Metalloprotease 17; COX-2 = Cyclooxygenase 2; E2 = Estrogen 2; EPAC1 = Exchange Protein Directly Activated by cAMP 1; ERK = Extracellular Signal-regulated Kinase; FAK = Focal Adhesion Kinase; FGFR2 = Fibroblast Growth Factor Receptor 2; GPR30 = G Protein-coupled Receptor 30; HIF = Hypoxia-inducible Factor; LXA4 = Lipoxin A4; MAPK = Mitogen-activated Protein Kinase; METTL3 = Methyltransferase-like 3; miR = micro RNA; MMP = Matrix Metallopeptidase; NF-κB = Nuclear Factor kappa B; NGF = Nerve growth factor; NLRP3 = NLR Family Pyrin Domain Containing 3; NO = Nitric Oxide; PGE2 = Prostaglandin E2; PKA = Protein Kinase A; PI3K/Akt/mTOR = Phosphatidylinositol 3-kinase/Protein Kinase B/mammalian Target of Rapamycin; PPAR = Peroxisome Proliferator-activated Receptor; PrPC = Cellular Prion Protein; Rap1 = Ras-associated Protein-1; ROCK = Rho-associated Protein Kinase; S1P = Sphingosine-1-Phosphate; SERCA = Sarcoplasmic/endoplasmic Reticulum Ca2+-ATPase; SF = Steroidogenic Factor; SHH = Sonic Hedgehog; SHP-1 = Src Homology Region 2 Domain-containing Phosphatase-1; sICAM-1 = soluble form of intercellular adhesion molecule-1; SMAD = Suppressor of Mothers against Decapentaplegic; SRC = Steroid Receptor Coactivator; TGF = Transforming Growth Factor; TIMP = Tissue Inhibitor of MMP; TNF = Tumor Necrosis Factor; VEGFR = Vascular Endothelial Growth Factor Receptor; ZEB1 = Zinc Finger E-Box Binding Homeobox 1

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Current (Pre-)Clinical Trials Investigating the Hallmarks of Endometriosis

In 2016, the kinase signaling pathways in endometriosis were investigated and it was concluded that the three main pathways to be targeted for treatment purposes are the IKKβ/NFκB, the MAPK, and the PI3K/AKT/mTOR pathway [20]. The literature on medications that specifically target the molecular and signaling pathways involved in the pathophysiology of endometriosis was thoroughly reviewed. The discussion included possible therapeutic targets, the molecules upstream and downstream that exhibit critical aberrant signaling, and the regulatory pathways that facilitate the expansion and maturation of endometriotic tissues and cells [21]. Recently, Shi also examined angiogenesis, lymphangiogenesis, neurogenesis, progesterone resistance, genetic alterations, estrogen-dependent induction of inflammation, imbalances in proliferation and apoptosis, and tissue remodeling in the pathogenesis of endometriosis. Additionally, the pharmacological mechanisms, constitutive relationships, and potential applications of each compound were studied as well [22]. Based on these works, a thorough search of both the ClinicalTrials.gov and the European Union Clinical Trials Register was conducted with a view to identifying completed and ongoing clinical studies investigating the role of the aforementioned pathways in patients with endometriosis. [Table 1] and [Table 2] briefly summarize the search results. [Table 3] provides a brief overview of the relevant preclinical studies.

Table 1 Completed registered clinical trials on the role of signaling pathways in endometriosis.

Agent

Pathway

Completed Clinical trial

Abbreviations: E2 = Estrogen 2; VEGF = Vascular Endothelial Growth Factor

Relugolix

Triptorelin

Linzagolix

ASP1707

FOR-6219

Leuprolide

Elagolix

Sufugolix

MK-8342B

Progesterone/Estradiol

GnRH-agonist

E2

NCT03204331

NCT03204318

NCT03654274

NCT03232281

NCT03992846

NCT01767090

NCT03709420

NCT02807363

NCT00797225

EudraCT Number: 2004–003829–28

EudraCT Number: 2004–001721–13

EudraCT Number: 2012–002791–14

EudraCT Number: 2012–002449–40

EudraCT Number: 2010–019287–37

EudraCT Number: 2013–003788–67

EudraCT Number: 2015–004326–34

EudraCT Number: 2015–004325–14

EudraCT Number: 2013–000993–32

Ezetimibe

Quinagolide

VEGF

NCT04844996

NCT00625950

EudraCT Number: 2018–000915–26

Anti-TNFα

Cytokines

NCT00604864

Table 2 Ongoing registered clinical trials on the role of signaling pathways in endometriosis.

Agent

Pathway

Clinical trial

Abbreviations: CXCL3 = Chemokine Ligand 3; GnRH = Gonadotropin-Releasing Hormone; IFN = Interferon; JNK = c-Jun N-terminal kinase; MAPK = Mitogen-Activated Protein Kinase; MMP = Matrix-Metalloprotease; NF-κB = Nuclear factor kappa-light-chain-enhancer of activated B cells; STAT3 = Signal transducer and activator of transcription 3; TNFα = Tumor Necrosis Factor-α; VEGFR = Vascular Endothelial Growth Factor Receptor; TGF = Transforming Growth Factor

Anastrazole plus GnRH agonist

Hormonal

Phase 4

NCT01769781

Danazol

Hormonal

Phase 4

NCT05697471

Resveratrol

Regulation of antioxidant enzymes, TNFα-mediated cytokines

Phase 4

NCT02475564

Vitamin D3 and fish oil

Anti-inflammatory

Phase 4

NCT02387931

Quinagolide

Dopaminergic, VEGF/VEGFR2

Phase 4

NCT03692403

DLBS1442

Anti-inflammatory, antiangiogenic, and apoptosis-inducing

Phase 3

NCT01942122

Pentoxifylline

VEGFC and VEGFR2

Phase 3

NCT00632697

Cabergoline

Dopaminergic

Phase 2

NCT02542410

Botulinum toxin

Neurotoxic

Phase 2

NCT01553201

Gefapixant

P2X3 receptor antagonist

Phase 2

NCT03654326

Vilaprisan

Selective progesterone receptor modulator

Phase 2

NCT03573336

Epigallocatechin gallate

TGF-β1-stimulated activation of MAPK and Smad pathway, VEGFC-mediated c-JUN, IFN-γ, CXCL3, and MMP-9 pathway

Phase 2

NCT02832271

Melatonin

Caspase, Radical scavenging activity

Phase 2

NCT03782740

MT-2990

Fully human anti-interleukin-33 monoclonal antibody

Phase 2

NCT03840993

Curcumin

p53/NF-κB, IκKα/β, STAT3, and JNK

Recruiting

NCT03016039

Table 3 Preclinical studies on the role of signaling pathways in endometriosis.

Agent

Pathway

Preclinical study

(cell culture/animal model/tissue sample)

Abbreviations: CBP = CREB binding protein; CDK = Cyclin dependent kinase; COX = Cyclooxygenase; CXCL3 = Chemokine (C-X-C motif) ligand 3; ER = Estrogen receptor; FOXO = Forkhead box transcription factors; GnRH = Gonadotropin-releasing hormone; IFN = Interferon; IκK = Inhibitor of kappa kinase; iNOS = Inducible-NO synthase; JNK = Jun N-terminal kinase; LATS1 = Large tumor suppressor kinase 1; LHRH = Luteinizing hormone-releasing hormone; MAPK = Mitogen-activated protein kinase; MMP = Matrix metallopeptidase; mTOR = Mammalian target of rapamycin; NF-κB = Nuclear factor kappa-light-chain-enhancer of activated B cells; NK = Natural killer; NO = Nitric oxide; PDTC = Pyrrolidine dithiocarbamate; PGE = Prostaglandin; PPARγ = Peroxisome proliferator-activated receptor gamma; RAF/MEK/ERK = Rapidly accelerated fibrosarcoma/mitogen-activated protein kinase/extracellular signal-regulated kinase; ROCK = Rho-associated, coiled-coil containing kinases; SMAD = Suppressor of mothers against decapentaplegic; STAT3 = Signal transducer and activator of transcription 3; TGF = Transforming growth factor; TNFα = Tumor necrosis factor α; TPCK = Tosyl phenylalanyl chloromethyl ketone; VEGF = Vascular endothelial growth factor; WNT2 = Wnt family member 2; YAP1 = Yes-associated protein 1

Indomethacin

COX-2

Mice model

Celecoxib

COX-2/PGE2, COX-2/VEGF

Primary human endometriotic stromal cells

BAY11-7085

Caspase and apoptotic proteins effects

Primary human endometriotic and endometrial stromal cells

Chloroindazole

E2/ER

Primary human endometriotic stromal cells and mice model

Oxabicycloheptene sulfonate

E2/ER

Primary human endometriotic stromal cells and mice model

Tunicamycin

ER stress

Primary human endometriotic and endometrial stromal cells

Verteporfin

Hypoxia/LATS1/YAP1

Primary human endometriotic stromal cells and mice model

Curcumin

p53/NF-κB, IκKα/β, STAT3, and JNK

Mice model

Genistein

COX-2 and NF-κB/MMP-2/MMP-9

Mice model

Sorafenib

RAF/MEK/ERK and VEGF/VEGFR

Primary human endometriotic stromal cells and mice xenograft model

Vemurafenib

MAPK/ERK

Primary human stromal epithelial; endometriotic/endometrial cells and animals mice xenograft model

U0126

MAPK/PR

Primary human endometriotic and endometrial stromal cells

Puerarin

MAPK/ERK1/2

Primary human endometriotic stromal cells

PGE2 inhibitors

EGFR/ERK1/2, Akt, B-catenin, NF-κB

Cell line (12Z and 22B), primary human endometriotic and endometrial stromal cells

WIN 55212-2

mTOR/Akt

Primary human stromal/epithelial; endometriotic/endometrial cells and mice xenograft model

Propofol

p53, p21, Caspase, FOXO, inducing apoptosis

Cell line (CRL-7566)

Dichloroacetate

Metabolic process

Primary human peritoneal mesothelial cells, cell line (SHT290), mice model

MK2206 and chloroquine

Akt/PR, Autophagy modulators regulated autophagy

Primary human stromal/epithelial; endometriotic/endometrial cells and mice xenograft model

Ginsenoside

NF-κB, E2/ER and PR, NK cells cytotoxicity

Primary human endometriotic and endometrial stromal cells and mice model

Müllerian inhibiting substance

ERK and Beclin1 inducing autophagy, CDK

Cell line (CRL-7566)

C-82

CBP/β-catenin

Primary human endometriotic and endometrial stromal cells

ICG-001

CBP/β-catenin

Primary human endometriotic and endometrial stromal cells and mice model

Metformin

Wnt2/β-catenin, cytokines

Primary human endometriotic and endometrial stromal cells, endometrial epithelial cell

PKF115-584/ CGP049090

Wnt/β-catenin

Primary human stromal/epithelial; endometriotic/endometrial cells

Fasudil

Rho/ROCK

Primary human endometriotic stromal cells

Heparin

Rho/ROCK

Primary human endometriotic stromal cells

Pazopanib, sunitinib and sorafenib

VEGF/VEGFR

Rat model

Pyrrolidine dithiocarbamate

NF-κB/TNFα/VEGF

Primary human endometriotic and endometrial stromal cells

Pentoxifylline

VEGFC and VEGFR2

Wistar rat model

N-acetylcysteine

Radical scavenging activity/ERK, cytokines

Primary human stromal/epithelial; endometriotic/endometrial cells, mice xenograft model

Caffeic Acid

Regulation of antioxidant enzymes

Primary human endometriotic and endometrial stromal cells

Crocin

Cytokines

Mice model and cell lines (HUVEC and THP-1)

ISO-1

Cytokines

Mice model

Puerarin

E2/ER

Rat model

Niclosamide

MAPK, Wnt pathway

Mice model

Acai

VEGF/VEGFR, iNOS/NO, COX-2/PGE2

Cell line (J774.G8) and Sprague-Dawley rats

Bortezomib

Proteasome

Wistar rats

TPCK

NF-κB

Endometriosis stromal cells

PDTC

IkappaB

Endometriosis stromal cells and Wistar rats

Thalidomide

IkappaB

Endometriosis stromal cells and Sprague-Dawley rats

Thiazolidinediones

PPARγ

Sprague-Dawley rats

Interleukin 10

DNA binding

Endometriosis stromal cells

Decoy Nucleotides

DNA binding

Endometriosis stromal cells

SB203580

Interleukin 1β

Endometriosis stromal cells

SP600125

JNK

Endometriosis stromal cells

Temsirolimus

mTOR

Endometriotic cells


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Discussion and Conclusion

A great number of extensive review articles has so far been published on the role of signaling pathways/molecules in endometriosis [16] [17] [18] [19] [20] [21] [22]. Of note, given some shared molecular (genetic) mechanisms, endometriosis seems to be associated with various risk factors and other disease entities such as migraine, autoimmunity and chronic pelvic pain [23] [24] [25] [26] ([Fig. 4]). Chronic pain, for instance, seems to share similar pathomechanisms as endometriosis in terms of abundance of proinflammatory molecules, angiogenesis and estrogen-dependent pain meditation [23]. Even though endometriosis is not yet officially classified as an autoimmune disease, there are a number of similarities between the two conditions, including a predominance of females (and hormones), immunological abnormalities, genetic polymorphisms, as well as chronicity [24]. In the case of migraine, mechanisms associated with sex hormone activities, protein adhesion, phosphorylation, inflammation or immune dysregulation seem to play a similar role as in the pathogenesis of endometriosis [25]. Endometriosis is a disease condition encountering gynecologists every single day in both the outpatient and the clinic routine. Patients seek medical advice either because of the adverse pain symptoms and/or due to the unfulfilled desire to become pregnant. Unfortunately, most patients are very disappointed once they learn that surgery does not grant the end of the disease and that the only possible symptomatic treatment is hormone-based. In times of targeted treatment therapies and ample possibilities to investigate and discover novel therapeutic approaches (i.e. inflammation, apoptosis, angiogenesis, cellular adhesion, etc.), endometriosis represents a profound example of an understudied disease that to date may only be treated symptomatically. The present work aims at raising the awareness of both researchers and clinicians in this context and to highlight the need of further research in order to establish and launch targeted therapies for the successful treatment of endometriosis patients. All in all, we herein intended to summarize the current research status and to point out the field’s novel therapeutic approaches. However, the considerable side effects of these targeted therapies need to be further examined and taken into consideration in the context of risk–benefit calculation.

Zoom Image
Fig. 4 Risk factors and associated conditions with endometriosis [14] [17] [23] [24] [25] [26].

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Contributorsʼ Statement

Conceptualization, I.P., M.W.B.; literature research, original manuscript preparation, art work, I.P.; review and supervision, S.B., K.A., L.H., L.W., L.L. and M.W.B. All authors have read and agreed to the published version of the manuscript.

Conflict of Interest

The authors declare that they have no conflict of interest.


Correspondence

Prof. Dr. med. Matthias W. Beckmann
Department of Gynecology and Obstetrics, Erlangen University Hospital, Friedrich Alexander University of Erlangen-Nuremberg
Universitätsstraße 21–23
91054 Erlangen
Germany   

Publication History

Received: 27 February 2024

Accepted after revision: 14 April 2024

Article published online:
13 June 2024

© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany


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Fig. 1 Deep infiltrating endometriosis-Intraoperative laparoscopic views (Patient collective-Department of Gynecology, University Hospital of Erlangen).
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Fig. 2 Diagnostic approaches based on the four major endometriotic entities.
Zoom Image
Fig. 3 Hallmarks of endometriosis and their potential targets for therapy. Captions in blue: completed clinical trials. Captions in green: ongoing clinical trials. Captions in black: experimental models in vitro/in vivo. Abbreviations: ADAM17 = A Disintegrin and Metalloprotease 17; COX-2 = Cyclooxygenase 2; E2 = Estrogen 2; EPAC1 = Exchange Protein Directly Activated by cAMP 1; ERK = Extracellular Signal-regulated Kinase; FAK = Focal Adhesion Kinase; FGFR2 = Fibroblast Growth Factor Receptor 2; GPR30 = G Protein-coupled Receptor 30; HIF = Hypoxia-inducible Factor; LXA4 = Lipoxin A4; MAPK = Mitogen-activated Protein Kinase; METTL3 = Methyltransferase-like 3; miR = micro RNA; MMP = Matrix Metallopeptidase; NF-κB = Nuclear Factor kappa B; NGF = Nerve growth factor; NLRP3 = NLR Family Pyrin Domain Containing 3; NO = Nitric Oxide; PGE2 = Prostaglandin E2; PKA = Protein Kinase A; PI3K/Akt/mTOR = Phosphatidylinositol 3-kinase/Protein Kinase B/mammalian Target of Rapamycin; PPAR = Peroxisome Proliferator-activated Receptor; PrPC = Cellular Prion Protein; Rap1 = Ras-associated Protein-1; ROCK = Rho-associated Protein Kinase; S1P = Sphingosine-1-Phosphate; SERCA = Sarcoplasmic/endoplasmic Reticulum Ca2+-ATPase; SF = Steroidogenic Factor; SHH = Sonic Hedgehog; SHP-1 = Src Homology Region 2 Domain-containing Phosphatase-1; sICAM-1 = soluble form of intercellular adhesion molecule-1; SMAD = Suppressor of Mothers against Decapentaplegic; SRC = Steroid Receptor Coactivator; TGF = Transforming Growth Factor; TIMP = Tissue Inhibitor of MMP; TNF = Tumor Necrosis Factor; VEGFR = Vascular Endothelial Growth Factor Receptor; ZEB1 = Zinc Finger E-Box Binding Homeobox 1
Zoom Image
Fig. 4 Risk factors and associated conditions with endometriosis [14] [17] [23] [24] [25] [26].