Molecular mechanism of autophagy and apoptosis in endometriosis: Current understanding and future research directions.

Background: Endometriosis is a common gynecological condition, with symptoms including pain and infertility. Regurgitated endometrial cells into the peritoneal cavity encounter hypoxia and nutrient starvation. Endometriotic cells have evolved various adaptive mechanisms to survive in this inevitable condition. These adaptations include escape from apoptosis. Autophagy, a self-degradation system, controls apoptosis during stress conditions. However, to date, the mechanisms regulating the interplay between autophagy and apoptosis are still poorly understood. In this review, we summarize the current understanding of the molecular characteristics of autophagy in endometriosis and discuss future therapeutic challenges. Methods: A search of PubMed and Google Scholar databases were used to identify relevant studies for this narrative literature review. Results: Autophagy may be dynamically regulated through various intrinsic (e.g., PI3K/AKT/mTOR signal transduction network) and extrinsic (e.g., hypoxia and iron-mediated oxidative stress) pathways, contributing to the development and progression of endometriosis. Upregulation of mTOR expression suppresses apoptosis via inhibiting the autophagy pathway, whereas hypoxia or excess iron often inhibits apoptosis via promoting autophagy. Conclusion: Endometriotic cells may have acquired antiapoptotic mechanisms through unique intrinsic and extrinsic autophagy pathways to survive in changing environments.

Current understanding of the pathogenesis of placenta accreta spectrum disorder with focus on mitochondrial function.

AIM: The refinement of assisted reproductive technology, including the development of cryopreservation techniques (vitrification) and ovarian stimulation protocols, makes frozen embryo transfer (FET) an alternative to fresh ET and has contributed to the success of assisted reproductive technology. Compared with fresh ET cycles, FET cycles were associated with better in vitro fertilization outcomes; however, the occurrence of pregnancy-induced hypertension, preeclampsia, and placenta accreta spectrum (PAS) was higher in FET cycles. PAS has been increasing steadily in incidence as a life-threatening condition along with cesarean rates worldwide. In this review, we summarize the current understanding of the pathogenesis of PAS and discuss future research directions. METHODS: A literature search was performed in the PubMed and Google Scholar databases. RESULTS: Risk factors associated with PAS incidence include a primary defect of the decidua basalis or scar dehiscence, aberrant vascular remodeling, and abnormally invasive trophoblasts, or a combination thereof. Freezing, thawing, and hormone replacement manipulations have been shown to affect multiple cellular pathways, including cell proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and mitochondrial function. Molecules involved in abnormal migration and EMT of extravillous trophoblast cells are beginning to be identified in PAS placentas. Many of these molecules were also found to be involved in mitochondrial biogenesis and dynamics. CONCLUSION: The etiology of PAS may be a multifactorial genesis with intrinsic predisposition (e.g., placental abnormalities) and certain environmental factors (e.g., defective decidua) as triggers for its development. A distinctive feature of this review is its focus on the potential factors linking mitochondrial function to PAS development.

Role of the mitophagy-apoptosis axis in the pathogenesis of polycystic ovarian syndrome.

AIM: Polycystic ovary syndrome (PCOS) is a common endocrine disorder characterized by menstrual irregularities, androgen excess, and polycystic ovarian morphology, but its pathogenesis remains largely unknown. This review focuses on how androgen excess influences the molecular basis of energy metabolism, mitochondrial function, and mitophagy in granulosa cells and oocytes, summarizes our current understanding of the pathogenesis of PCOS, and discuss perspectives on future research directions. METHODS: A search of PubMed and Google Scholar databases were used to identify relevant studies for this narrative literature review. RESULTS: Female offspring born of pregnant animals exposed to androgens recapitulates the PCOS phenotype. Abnormal mitochondrial morphology, altered expression of genes related to glycolysis, mitochondrial biogenesis, fission/fusion dynamics, and mitophagy have been identified in PCOS patients and androgenic animal models. Androgen excess causes uncoupling of the electron transport chain and depletion of the cellular adenosine 5'-triphosphate pool, indicating further impairment of mitochondrial function. A shift toward mitochondrial fission restores mitochondrial quality control mechanisms. However, prolonged mitochondrial fission disrupts autophagy/mitophagy induction due to loss of compensatory reserve for mitochondrial biogenesis. Disruption of compensatory mechanisms that mediate the quality control switch from mitophagy to apoptosis may cause a disease phenotype. Furthermore, genetic predisposition, altered expression of genes related to glycolysis and oxidative phosphorylation, or a combination of these factors may also contribute to the development of PCOS. CONCLUSION: In conclusion, fetuses exposed to a hyperandrogenemic intrauterine environment may cause the PCOS phenotype possibly through disruption of the compensatory regulation of the mitophagy-apoptosis axis.

An integral role of mitochondrial function in the pathophysiology of preeclampsia.

Preeclampsia (PE) is associated with high maternal and perinatal morbidity and mortality. The development of effective treatment strategies remains a major challenge due to the limited understanding of the pathogenesis. In this review, we summarize the current understanding of PE research, focusing on the molecular basis of mitochondrial function in normal and PE placentas, and discuss perspectives on future research directions. Mitochondria integrate numerous physiological processes such as energy production, cellular redox homeostasis, mitochondrial dynamics, and mitophagy, a selective autophagic clearance of damaged or dysfunctional mitochondria. Normal placental mitochondria have evolved innovative survival strategies to cope with uncertain environments (e.g., hypoxia and nutrient starvation). Cytotrophoblasts, extravillous trophoblast cells, and syncytiotrophoblasts all have distinct mitochondrial morphology and function. Recent advances in molecular studies on the spatial and temporal changes in normal mitochondrial function are providing valuable insight into PE pathogenesis. In PE placentas, hypoxia-mediated mitochondrial fission may induce activation of mitophagy machinery, leading to increased mitochondrial fragmentation and placental tissue damage over time. Repair mechanisms in mitochondrial function restore placental function, but disruption of compensatory mechanisms can induce apoptotic death of trophoblast cells. Additionally, molecular markers associated with repair or compensatory mechanisms that may influence the development and progression of PE are beginning to be identified. However, contradictory results have been obtained regarding some of the molecules that control mitochondrial biogenesis, dynamics, and mitophagy in PE placentas. In conclusion, understanding how the mitochondrial morphology and function influence cell fate decisions of trophoblast cells is an important issue in normal as well as pathological placentation biology. Research focusing on mitochondrial function will become increasingly important for elucidating the pathogenesis and effective treatment strategies of PE.

Altered Energy Metabolism, Mitochondrial Dysfunction, and Redox Imbalance Influencing Reproductive Performance in Granulosa Cells and Oocyte During Aging.

Female fertility decreases during aging. The development of effective therapeutic strategies to address the age-related decline in oocyte quality and quantity and its accurate diagnosis remain major challenges. In this review, we summarize our current understanding of the study of aging and infertility, focusing primarily on the molecular basis of energy metabolism, mitochondrial function, and redox homeostasis in granulosa cells and oocytes, and discuss perspectives on future research directions. Mitochondria serve as a central hub sensing a multitude of physiological processes, including energy production, cellular redox homeostasis, aging, and senescence. Young granulosa cells favor glycolysis and actively produce pyruvate, NADPH, and other metabolites. Oocytes rely on oxidative phosphorylation fueled by nutrients, metabolites, and antioxidants provided by the adjacent granulosa cells. A reduced cellular energy metabolism phenotype, including both aerobic glycolysis and mitochondrial respiration, is characteristic of older female granulosa cells compared with younger female granulosa cells. Aged oocytes become more susceptible to oxidative damage to cells and mitochondria because of further depletion of antioxidant-dependent ROS scavenging systems. Molecular perturbations of gene expression caused by a subtle change in the follicular fluid microenvironment adversely affect energy metabolism and mitochondrial dynamics in granulosa cells and oocytes, further causing redox imbalance and accelerating aging and senescence. Furthermore, recent advances in technology are beginning to identify biofluid molecular markers that may influence follicular development and oocyte quality. Accumulating evidence suggests that redox imbalance caused by abnormal energy metabolism and/or mitochondrial dysfunction is closely linked to the pathophysiology of age-related subfertility.

A comprehensive overview of recent developments on the mechanisms and pathways of ferroptosis in cancer: the potential implications for therapeutic strategies in ovarian cancer.

Cancer cells adapt to environmental changes and alter their metabolic pathways to promote survival and proliferation. Metabolic reprogramming not only allows tumor cells to maintain a reduction-oxidation balance by rewiring resources for survival, but also causes nutrient addiction or metabolic vulnerability. Ferroptosis is a form of regulated cell death characterized by the iron-dependent accumulation of lipid peroxides. Excess iron in ovarian cancer amplifies free oxidative radicals and drives the Fenton reaction, thereby inducing ferroptosis. However, ovarian cancer is characterized by ferroptosis resistance. Therefore, the induction of ferroptosis is an exciting new targeted therapy for ovarian cancer. In this review, potential metabolic pathways targeting ferroptosis were summarized to promote anticancer effects, and current knowledge and future perspectives on ferroptosis for ovarian cancer therapy were discussed. Two therapeutic strategies were highlighted in this review: directly inducing the ferroptosis pathway and targeting metabolic vulnerabilities that affect ferroptosis. The overexpression of SLC7A11, a cystine/glutamate antiporter SLC7A11 (also known as xCT), is involved in the suppression of ferroptosis. xCT inhibition by ferroptosis inducers (e.g., erastin) can promote cell death when carbon as an energy source of glucose, glutamine, or fatty acids is abundant. On the contrary, xCT regulation has been reported to be highly dependent on the metabolic vulnerability. Drugs that target intrinsic metabolic vulnerabilities (e.g., GLUT1 inhibitors, PDK4 inhibitors, or glutaminase inhibitors) predispose cancer cells to death, which is triggered by decreased nicotinamide adenine dinucleotide phosphate generation or increased reactive oxygen species accumulation. Therefore, therapeutic approaches that either directly inhibit the xCT pathway or target metabolic vulnerabilities may be effective in overcoming ferroptosis resistance. Real-time monitoring of changes in metabolic pathways may aid in selecting personalized treatment modalities. Despite the rapid development of ferroptosis-inducing agents, therapeutic strategies targeting metabolic vulnerability remain in their infancy. Thus, further studies must be conducted to comprehensively understand the precise mechanism linking metabolic rewiring with ferroptosis.

The role of mitochondrial dynamics in the pathophysiology of endometriosis.

AIM: Endometriosis is a chronic disease of reproductive age, associated with pelvic pain and infertility. Endometriotic cells adapt to changing environments such as oxidative stress and hypoxia in order to survive. However, the underlying mechanisms remain to be fully elucidated. In this review, we summarize our current understanding of the pathogenesis of endometriosis, focusing primarily on the molecular basis of energy metabolism, redox homeostasis, and mitochondrial function, and discuss perspectives on future research directions. METHODS: Papers published up to March 31, 2023 in the PubMed and Google Scholar databases were included in this narrative literature review. RESULTS: Mitochondria serve as a central hub sensing a multitude of physiological processes, including energy production and cellular redox homeostasis. Under hypoxia, endometriotic cells favor glycolysis and actively produce pyruvate, nicotinamide adenine dinucleotide phosphate (NADPH), and other metabolites for cell proliferation. Mitochondrial fission and fusion dynamics may regulate the phenotypic plasticity of cellular energy metabolism, that is, aerobic glycolysis or OXPHOS. Endometriotic cells have been reported to have reduced mitochondrial numbers, increased lamellar cristae, improved energy efficiency, and enhanced cell proliferation and survival. Increased mitochondrial fission and fusion turnover by hypoxic and normoxic conditions suggests an activation of mitochondrial quality control mechanisms. Recently, candidate molecules that influence mitochondrial dynamics have begun to be identified. CONCLUSION: This review suggests that unique energy metabolism and redox homeostasis driven by mitochondrial dynamics may be linked to the pathophysiology of endometriosis. However, further studies are needed to elucidate the regulatory mechanisms of mitochondrial dynamics in endometriosis.

Tissue factor pathway inhibitor 2: Current understanding, challenges, and future perspectives.

AIM: Tissue factor pathway inhibitor 2 (TFPI2) is a structural homolog of tissue factor pathway inhibitor 1 (TFPI1). Since TFPI2 is a placenta-derived protein, dynamic changes in TFPI2 levels may be related to pregnancy-related diseases. Furthermore, TFPI2 has been reported to be a novel serum biomarker for detecting ovarian cancer, especially clear cell carcinoma (CCC). This review aims to summarize the current knowledge on the biological function of TFPI2, highlight the major challenges that remain to be addressed, and discuss future research directions. METHODS: Papers published up to March 31, 2023 in the PubMed and Google Scholar databases were included in this review. We also provide novel complementary information to what is known about the action of TFPI2. RESULTS: Since TFPI2 concentrations in the blood of pregnant women, preeclampsia patients, and cancer patients vary greatly, its pathophysiological functions have attracted attention. Downregulation of TFPI2, a tumor-suppressor gene, by hypermethylation may contribute to the progression of several cancers. On the other hand, TFPI2 overexpressed in CCC is a risk factor for the development of thrombosis, possibly through inhibition of plasmin activity. However, agreement on the biological function of TFPI2 is still lacking and there are many scientific questions to be addressed. In particular, the lack of international standardization for the quantification of TFPI2 concentrations makes it difficult for researchers and clinicians to evaluate, pool, and compare data from different studies across countries. DISCUSSION: This review summarizes current understandings and challenges in TFPI2 research and discusses future perspectives.

Current Understanding of and Future Directions for Endometriosis-Related Infertility Research with a Focus on Ferroptosis.

BACKGROUND: To date, the development of therapy for endometriosis and disease-related infertility remains a major challenge. Iron overload caused by periodic bleeding is a hallmark of endometriosis. Ferroptosis is an iron- and lipid-reactive oxygen species-dependent type of programmed cell death that is distinct from apoptosis, necrosis, and autophagy. This review summarizes the current understanding of and future directions for the research and treatment of endometriosis and disease-related infertility, with the main focus on the molecular basis of ferroptosis in endometriotic and granulosa cells. METHODS: Papers published between 2000 and 2022 in the PubMed and Google Scholar databases were included in this review. RESULTS: Emerging evidence suggests that ferroptosis is closely linked to the pathophysiology of endometriosis. Endometriotic cells are characterized by ferroptosis resistance, whereas granulosa cells remain highly susceptible to ferroptosis, suggesting that the regulation of ferroptosis is utilized as an interventional target for research into the treatment of endometriosis and disease-related infertility. New therapeutic strategies are urgently needed to efficiently kill endometriotic cells while protecting granulosa cells. CONCLUSIONS: An analysis of the ferroptosis pathway in in vitro, in vivo, and animal research enhances our understanding of the pathogenesis of this disease. Here, we discuss the role of ferroptosis modulators as a research approach and potential novel treatment for endometriosis and disease-related infertility.

Tissue Factor Pathway Inhibitors as Potential Targets for Understanding the Pathophysiology of Preeclampsia.

BACKGROUND: Preeclampsia is a hypertensive disorder of pregnancy that causes maternal and perinatal morbidity and mortality worldwide. Preeclampsia is associated with complex abnormalities of the coagulation and fibrinolytic system. Tissue factor (TF) is involved in the hemostatic system during pregnancy, while the Tissue Factor Pathway Inhibitor (TFPI) is a major physiological inhibitor of the TF-initiated coagulation cascade. The imbalance in hemostatic mechanisms may lead to a hypercoagulable state, but prior research has not comprehensively investigated the roles of TFPI1 and TFPI2 in preeclamptic patients. In this review, we summarize our current understanding of the biological functions of TFPI1 and TFPI2 and discuss future directions in preeclampsia research. METHODS: A literature search was performed from inception to 30 June 2022 in the PubMed and Google Scholar databases. RESULTS: TFPI1 and TFPI2 are homologues with different protease inhibitory activities in the coagulation and fibrinolysis system. TFPI1 is an essential physiological inhibitor of the TF-initiated extrinsic pathway of coagulation. On the other hand, TFPI2 inhibits plasmin-mediated fibrinolysis and exerts antifibrinolytic activity. It also inhibits plasmin-mediated inactivation of clotting factors and maintains a hypercoagulable state. Furthermore, in contrast to TFPI1, TFPI2 suppresses trophoblast cell proliferation and invasion and promotes cell apoptosis. TFPI1 and TFPI2 may play important roles in regulating the coagulation and fibrinolytic system and trophoblast invasion to establish and maintain successful pregnancies. Concentrations of TF, TFPI1, and TFPI2 in maternal blood and placental tissue are significantly altered in preeclamptic women compared to normal pregnancies. CONCLUSIONS: TFPI protein family may affect both the anticoagulant (i.e., TFPI1) and antifibrinolytic/procoagulant (i.e., TFPI2) systems. TFPI1 and TFPI2 may function as new predictive biomarkers for preeclampsia and navigate precision therapy.

Shared Molecular Features Linking Endometriosis and Obstetric Complications.

Recent epidemiological research has shown the increased risk of adverse pregnancy outcomes in women with endometriosis compared with the general population. The aim of this review is to explore common pathophysiologic mechanisms between endometriosis and obstetric complications. A computerized literature search was performed to identify relevant studies. The search covered the period between January 2008 and October 2018. One of the potential mechanisms driving the initiation and progression of endometriosis is the accumulation of a variety of epigenetic changes in endometrial cells. Epigenetic control of gene expression which is considered to be responsible for the development of endometriosis is commonly seen in patients with preeclampsia, small for gestational age (SGA), or preterm birth. DLX5 and GATA3, paternally imprinted genes, and CDKN1C, a maternally imprinted gene, were aberrantly expressed in placenta tissues of the preeclampsia; CDKN1C, the growth inhibitor gene, was upregulated in human SGA placentas; and hypomethylation of PTGER2 would be associated with preterm birth. Preeclampsia, SGA, or preterm birth may share common epigenetic alterations with endometriosis, which raises the possibility that the occurrence of two conditions might be nonrandom. To date, however, there is a lack of evidence that links endometriosis and other obstetric complications, such as postpartum hemorrhage or placental abruption, at the epigenetic level. In conclusion, epigenetic changes may be a common hallmark of two conditions: endometriosis and obstetrical complications, such as preeclampsia, SGA, or preterm birth.

A Relationship Between Endometriosis and Obstetric Complications.

The aim of this review is to summarize the current literature regarding a link between endometriosis and adverse pregnancy outcomes. We also present an overview of common pathogenic mechanisms between endometriosis and obstetric complications. A computerized literature search was performed to identify relevant studies. The search covered the period between January 2008 and October 2018. Emerging evidence has revealed that endometriosis increased the risk of preterm birth, miscarriage, preterm premature rupture of membranes, placenta previa, preeclampsia, pregnancy-induced hypertension (PIH), gestational diabetes, gestational cholestasis, small for gestational age (SGA) babies, antepartum hemorrhage, postpartum hemorrhage, placental abruption, retained placenta, malpresentation, labor dystocia, cesarean delivery, stillbirth, neonatal death, and congenital malformations of the uterus, but the data are based on limited information. However, some studies have found that endometriosis did not affect pregnancy outcomes. Previous studies are heterogenous and the existing data are controversial. Limited evidence from a few studies also indicated that surgical excision of endometriosis may not reduce the risk of adverse pregnancy outcomes. Endometriosis and obstetric complications may share common pathophysiologic mechanisms, in which abnormal activation of inflammation, structural and functional alterations in the junctional zone, and perturbed uterine peristalsis may play important roles. In this review, we outlined evidence that women with endometriosis have a high risk of obstetric complications. We describe the common crucial features between endometriosis and obstetric complications.

Magnetic resonance relaxometry improves the accuracy of conventional MRI in the diagnosis of endometriosis-associated ovarian cancer: A case report.

Endometriosis is a precancerous condition for endometriosis-associated ovarian cancer (EAOC). In the present study, conventional magnetic resonance imaging (MRI) and MR relaxometry were used to examine a case of clear cell carcinoma that arose in a pre-existing right-sided benign ovarian endometrioma (OE). The 42-year-old nulliparous woman suspected of EOAC, as assessed by conventional MRI, requested fertility-sparing surgery such as laparoscopic endometrioma cystectomy. Furthermore, the MR transverse relaxation rate (R2) was determined using a single-voxel, multi-echo MR sequence using a 3 Tesla-MR system. An R2 value <12.1 s-1 was indicative of malignancy, as described in previous studies. In the present study, MR relaxometry identified an R2 value of 7.98 s-1 in the right cyst, which suggested the malignant transformation of benign OE. Based on these findings, fertility-sparing surgery was contraindicated. In conclusion, MR relaxometry may represent a new clinical approach as an adjunctive modality for the diagnosis of EAOC. When patients exhibiting a pelvic mass suspected of EAOC desire fertility-sparing treatment options, MR relaxometry can facilitate the selection of conservative management.

Immunohistochemical expression of CD44v9 and 8-OHdG in ovarian endometrioma and the benign endometriotic lesions adjacent to clear cell carcinoma.

AIM: Expression of CD44 variant isoforms (CD44v) promotes the synthesis of reduced glutathione and contributes to reactive oxygen species defense through up-regulation of the intracellular antioxidant. The aim of the study was to investigate the expression of CD44v9 and oxidative DNA damage marker, 8-OHdG, in benign ovarian endometrioma (OE) and OE harboring clear cell carcinomas (CCC). METHODS: A retrospective study was performed at the Department of Gynecology, Nara Medical University hospital from January 2006 to December 2012. Patients with histologically confirmed benign OE (n = 27) and OE harboring areas of CCC (n = 8) were selected. Tissue samples were immunohistochemically analyzed for the presence of CD44v9 and 8-OHdG using avidin-biotin complex method. RESULTS: CD44v9 was located on the cell membrane of endometriotic epithelial cells and expressed in 88.9% (24/27) of benign OE tissues. Only 25.0% (2/8) of benign endometriotic lesions adjacent to CCC was found to stain weakly for CD44v9. Percentage of CD44v9 positive cells was 68.5 ± 20.2% (mean ± standard deviation) of benign OE, 16.7 ± 16.5% of CCC endometriotic tissue (P < 0.001). Compared to benign OE, CCC endometriotic tissue showed a significant increase in the proportion of 8-OHdG expression (77.3 ± 22.5% vs 94.9 ± 3.0%, P = 0.049). A significant negative correlation was observed between CD44v9 status and 8-OHdG nuclear expression (r = -0.458, P  =  0.006). CONCLUSION: Alterations in CD44v9 and 8-OHdG may be associated with malignant transformation of benign OE.

A diagnostic challenge of seromucinous borderline tumor: A case report.

INTRODUCTION: Magnetic resonance (MR) relaxometry provides a noninvasive predictive tool to discriminate between benign ovarian endometrioma (OE) and endometriosis-associated ovarian cancer (EAOC). Transverse relaxation rate R2 value was determined using a single-voxel, multi-echo MR sequence (HISTO) by a 3T-MR system. R2 with cutoff value of 12.1 s was established to discriminate between benign and malignant tumors. PATIENT CONCERNS: We present a case of a 39-year-old woman who was initially thought to be malignant transformation of endometriosis by diagnostic MR imaging of the vascularized solid components. DIAGNOSIS: A R2 value of 42.62 s on MR relaxometry demonstrated that this case is non-malignant. INTERVENTIONS: To confirm the diagnose, left salpingo-oophorectomy by laparoscopic surgery was performed. OUTCOMES: Histopathological results revealed seromucinous borderline tumor (SMBT). Our experience suggests that preoperative MR relaxometry may be useful for discriminating "borderline (SMBT)" from "malignancy (EAOC)." Furthermore, immunohistochemical studies of this case demonstrated ovarian SMBT cells were positive for estrogen receptor, progesterone receptor, and hepatocyte nuclear factor-1beta. A similar expression pattern was also observed in patients with benign OE. LESSONS: In many respects, SMBT characteristics differ from those of EAOC but resemble those of benign OE. MR relaxometry unveils a new clinical approach as an adjunctive modality for discriminating SMBT from EAOC.

Magnetic resonance imaging findings for discriminating clear cell carcinoma and endometrioid carcinoma of the ovary.

BACKGROUND: Common cancerous histological types associated with endometriosis are clear cell carcinoma (CCC) and endometrioid carcinoma (EC). CCC is regarded as an aggressive, chemoresistant histological subtype. Magnetic resonance imaging (MRI) offers some potential advantages to diagnose ovarian tumors compared with ultrasonography or computed tomography. This study aimed to identify MRI features that can be used to differentiate between CCC and EC. METHODS: We searched medical records of patients with ovarian cancers who underwent surgical treatment at Nara Medical University Hospital between January 2008 and September 2018; we identified 98 patients with CCC or EC who had undergone preoperative MRI. Contrasted MRI scans were performed less than 2 months before surgery. Patients were excluded from the study if they had no pathology, other pathological subtype of epithelial ovarian cancer, and/or salvage treatment for recurrence and metastatic ovarian cancer at the time of study initiation. Clinically relevant variables that were statistically significant by univariate analysis were selected for subsequent multivariate regression analysis to identify independent factors to distinguish CCC from EC. RESULTS: MRI of CCC and EC showed a large cystic heterogeneous mixed mass with mural nodules protruding into the cystic space. Univariate logistic regression analysis revealed that the growth pattern (broad-based nodular structures [multifocal/concentric sign] or polypoid structures [focal/eccentric sign]), surface irregularity (a smooth/regular surface or a rough/irregular/lobulated surface), "Width" of mural nodule, "Height-to-Width" ratio (HWR), and presence of preoperative ascites were factors that significantly differed between CCC and EC. In the multivariate logistic regression analysis, the growth pattern of the mural nodule (odds ratio [OR] = 0.69, 95% confidence interval [CI]: 0.013-0.273, p = 0.0004) and the HWR (OR = 3.71, 95% CI: 1.128-13.438, p = 0.036) were independent predictors to distinguish CCC from EC. CONCLUSIONS: In conclusion, MRI data showed that the growth pattern of mural nodules and the HWR were independent factors that could allow differentiation between CCC and EC. This finding may be helpful to predict patient prognosis before operation.

Modern approaches to noninvasive diagnosis of malignant transformation of endometriosis.

Endometriosis-associated ovarian cancer (EAOC) is a rare entity and has highly variable morphological presentations. Mural nodules can be seen in EAOC and benign ovarian endometrioma (OE), which causes a diagnostic dilemma. The differential diagnosis between early-stage EAOC with predominantly cystic appearances and benign OE remains a challenge for physicians. This study will summarize recent knowledge of diagnosis of malignant transformation of endometriosis that have been studied through an innovative approach based on a wide array of novel technologies. Using PubMed database, we focused on the biochemical and technical advancement in the differential diagnosis of benign and malignant endometriosis. Compared with the subjects with benign OE, cyst fluid hemoglobin and iron-related compounds levels were significantly lower in patients with EAOC. This observation opens up the possibility of early diagnosis before morphological variations are captured through ultrasonographic and magnetic resonance (MR) imaging diagnosis. The metallobiology technology offers one solution to this challenge. We discuss the noninvasive diagnosis of EAOC via various imaging methods, including electronic absorption spectroscopy, near infrared approach and MR transverse relaxometry. Special emphasis is given to recent advances in the noninvasive imaging modalities.

Integrating modern approaches to pathogenetic concepts of malignant transformation of endometriosis.

In the present study, we summarize the role of the shared and independent (epi)genetic background between endometrioid carcinoma (EC) and clear cell carcinoma (CCC), two histological subtypes of endometriosis-associated ovarian cancer (EAOC). Using the PubMed database, we conducted a literature review of various studies related to the malignant transformation of endometriosis. Both endometriosis and EAOC face potential environmental hazards, including hemoglobin (Hb), heme and free iron, which induces DNA damage and mutations. Although EC is distinguished from CCC due to different morphologies, both represent common environmental profiles and maintain the similar (epi)genomic abnormalities with multiple overlaps and share similar molecular signatures. By contrast, EAOC also has disease-specific gene signatures corresponding with each histological subtype: Estrogen receptor promotes EC cell proliferation ('go') and hepatocyte nuclear factor-1ß (HNF-1ß) induces CCC cell cycle arrest ('stop') under oxidative stress conditions. This model underscores a subtype-dependent 'go or stop' dichotomy, possibly through better ability to adapt in a changing environment. It was found that cyst fluid Hb and iron concentrations were significantly lower in EAOC when compared to benign ovarian endometrioma (OE), supporting the hypothesis that the redox imbalance plays a key role in the pathogenesis of EAOC. There are at least two phases of iron carcinogenesis and tumor progression: The initial wave of iron-induced oxidative stress and DNA mutations would be followed by the second big wave of subsequent synthesis of the antioxidants, which diminishes cellular oxidative stress capacity, increases apoptosis resistance and promotes tumor initiation and progression. Special emphasis is given to novel pathophysiological concepts of malignant transformation of endometriosis.

Comparison of redox parameters in ovarian endometrioma and its malignant transformation.

The present study aimed to evaluate the levels of oxidative stress and antioxidant markers in benign endometrioma (OE) and its malignant transformation [endometriosis-associated ovarian cancer (EAOC)] by measuring 8-hydroxy-2-deoxyguanosine (8-OHdG), heme oxygenase-1 (HO-1) and total antioxidant capacity (TAC/Heme-iron) alterations associated with disease progression. Cyst fluid samples from 44 patients with OE and 14 patients with EAOC were studied using an enzyme-linked immunosorbent assay. A χ2 test, t-test and Pearson correlation test were performed using SPSS version 22.0. The cut-off point, sensitivity and specificity of each marker for EAOC diagnosis were evaluated by receiver operating characteristic curve analysis. Cyst fluid 8-OHdG and HO-1 levels in the EAOC group were significantly decreased compared with the OE subjects (P=0.013 and P<0.001, respectively). The levels of TAC/Heme-iron in patients with EAOC were significantly higher compared with those in the OE subjects (P<0.001). The present study demonstrated a positive correlation between 8-OHdG and HO-1 levels (P=0.012). HO-1 exhibited the highest discriminant value for EAOC (Area Under the Curve=0.901). The optimal cut-off point of HO-1 for the diagnosis of EAOC was 2.314 ng/ml, with a sensitivity and specifity of 95.2 and 85.7%, respectively. The present study revealed a clear separation between the overall redox state in OE and EAOC. It was concluded that characteristic alterations in important factors in redox may be helpful for understanding the pathogenesis of the malignant transformation of endometriosis.

The HNF-1ß-USP28-Claspin pathway upregulates DNA damage-induced Chk1 activation in ovarian clear cell carcinoma.

Transcription factor hepatocyte nuclear factor 1-beta (HNF-1ß) enhances checkpoint kinase 1 (Chk1) activation and promotes G2/M cell cycle progression in ovarian clear cell carcinoma (CCC) following exposure to diverse genotoxic agents including bleomycin. However, the underlying mechanism leading to checkpoint activation of HNF-1ß still remains largely unknown. To clarify the effects of HNF-1ß on cell cycle checkpoints, human CCC cell lines were transfected with siRNAs targeting HNF-1ß, Claspin, USP28, or a control vector. Ubiquitination and stabilization of Claspin protein by HNF-1ß was assessed by immunoprecipitation. Loss-of-function studies using RNAi-mediated gene silencing indicated that HNF-1ß facilitated the Claspin expression after treatment with a genotoxic agent bleomycin, resulting in accumulation of phosphorylated Chk1 (p-Chk1) and promotion of survival in CCC cell lines. This study showed for the first time that USP28, a de-ubiquitinase crucial for Claspin expression, is one target gene of HNF-1ß. Knockdown of endogenous USP28 suppressed the Claspin expression and p-Chk1 activation and cell viability. Our findings identify a novel pathway of the HNF-1ß-USP28-Claspin-Chk1 axis in checkpoint signal amplification in response to DNA damage. Targeting this pathway may represent a putative, novel, anticancer strategy in ovarian CCC.