Hypoxia and the endometrium: An indispensable role for HIF-1α as therapeutic strategies.

Hypoxia-inducible factor 1 alpha (HIF-1α) is a major molecular mediator of the hypoxic response. In the endometrium, local hypoxic conditions induced by hormonal fluctuations and endometrial vascular remodeling contribute to the production of HIF-1α, which plays an indispensable role in a series of physiological activities, such as menstruation and metamorphosis. The sensitive regulation of HIF-1α maintains the cellular viability and regenerative capacity of the endometrium against cellular stresses induced by hypoxia and excess reactive oxygen species. In contrast, abnormal HIF-1α levels exacerbate the development of various endometrial pathologies. This knowledge opens important possibilities for the development of promising HIF-1α-centered strategies to ameliorate endometrial disease. Nonetheless, additional efforts are required to elucidate the regulatory network of endometrial HIF-1α and promote the applications of HIF-1α-centered strategies in the human endometrium. Here, we summarize the role of the HIF-1α-mediated pathway in endometrial physiology and pathology, highlight the latest HIF-1α-centered strategies for treating endometrial diseases, and improve endometrial receptivity.

Role of the gut microbiota in the pathogenesis of endometriosis: a review.

Endometriosis is classically defined as a chronic inflammatory heterogeneous disorder occurring in any part of the body, characterized by estrogen-driven periodic bleeding, proliferation, and fibrosis of ectopic endometrial glands and stroma outside the uterus. Endometriosis can take overwhelmingly serious damage to the structure and function of multi-organ, even impair whole-body systems, resulting in severe dysmenorrhea, chronic pelvic pain, infertility, fatigue and depression in 5-10% women of reproductive age. Precisely because of a huge deficiency of cognition about underlying etiology and complex pathogenesis of the debilitating disease, early diagnosis and treatment modalities with relatively minor side effects become bottlenecks in endometriosis. Thus, endometriosis warrants deeper exploration and expanded investigation in pathogenesis. The gut microbiota plays a significant role in chronic diseases in humans by acting as an important participant and regulator in the metabolism and immunity of the body. Increasingly, studies have shown that the gut microbiota is closely related to inflammation, estrogen metabolism, and immunity resulting in the development and progression of endometriosis. In this review, we discuss the diverse mechanisms of endometriosis closely related to the gut microbiota in order to provide new approaches for deeper exploration and expanded investigation for endometriosis on prevention, early diagnosis and treatment.

Effectiveness and safety of PD-1/PD-L1 inhibitors in advanced or recurrent endometrial cancer: a systematic review and meta-analysis.

Background: Studies in recent years have shown that PD-1/PD-L1 inhibitors may have better effectiveness in patients with advanced or recurrent endometrial cancer. The effectiveness of PD-1/PD-L1 inhibitors is thought to be related to mismatch repair-deficient (dMMR) and mismatch repair-proficient (pMMR) classification in advanced or recurrent endometrial cancer. This study aims to evaluate the effectiveness of PD-1/PD-L1 inhibitors in patients classified as dMMR and pMMR. Methods: Medical databases were searched to identify relevant publications up to 30 November 2022. The primary outcome was comparison of objective response rate (ORR) in patients with dMMR and pMMR following treatment with PD-1/PD-L1 inhibitors; secondary outcomes were single-group ORR in patients with dMMR and in patients with pMMR, respectively. Results: Eleven studies were eligible for analysis and patients with advanced or recurrent endometrial cancer with molecular classification of dMMR had a higher total ORR than those with pMMR [odds ratio (OR), 7.70; 95% confidence interval (CI), 3.22-18.38; p < 0.01], with low evidence of between-study heterogeneity (I2 = 0%). The total ORR of patients with advanced or recurrent endometrial cancer with molecular type dMMR was 51.9% (95% CI, 33.6%-69.9%). The overall ORR of patients with advanced or recurrent endometrial cancer with molecular type pMMR was 16.1% (95% CI, 5.5%-30.3%). Conclusion: In our including studies, the patients with advanced or recurrent endometrial cancer with molecular types of dMMR and pMMR, following treatment with PD-1/PD-L1 inhibitors, the total ORR of patients with dMMR was higher than that of patients with pMMR. Since the current number of studies is not very large, it is possible that more studies will be published in the future and more precise results will be discussed further.

Platelet-to-Lymphocyte Ratio and CA125 Level as a Combined Biomarker for Diagnosing Endometriosis and Predicting Pelvic Adhesion Severity.

Adhesion is a significant biological characteristic of endometriosis, and accurate evaluation of the pelvic adhesion is necessary for surgical treatment. Serum CA125 is yet the most common used biomarker in the diagnosis and follow-up of patients with endometriosis despite of its high false-positive rate and low specificity. Herein, we aimed to examine the diagnostic value of the combination of the platelet-to-lymphocyte ratio (PLR) and CA125 for patients with different stages of endometriosis and their correlations with pelvic adhesion. We retrospectively analyzed the clinical data and blood count parameters of patients with both endometriosis and other benign ovarian tumors. The mean level of CA125, the PLR and the combined marker (the CA125 level multiplied by the PLR) in the EMs group were significantly higher than those in the Cyst group (P < 0.05). ROC curve analysis was used to compare the diagnostic values of serum PLR, CA125, and the combined marker in ovarian endometriosis. The cut-off value of the PLR was 176.835, with 28.3% sensitivity and 96.9% specificity. The cut-off value of CA125 was 31.67 U/mL, with 84.1% sensitivity and 87.4% specificity. The cut-off value of the combined marker was 3894.97, with 83.4% sensitivity and 95.8% specificity. It was found that the severity of adhesion in endometriosis was positively correlated with the PLR (r = 0.286, P < 0.01), CA125 (r = 0.276, P < 0.01), and combined marker (r = 0.369, P < 0.01). The combined marker showed the highest AUC value (0.751, 95% CI: 0.666-0.837), with a sensitivity of 56.0% and a specificity of 89.6%, and the cut-off value was 9056.94. Besides, the levels of CA125, PLR, and their combination were significantly elevated in patients with endometriosis. The combined marker was not only positively correlated with pelvic adhesion but also showed a greater diagnostic value and specificity than CA125 alone. These findings indicate that the combined marker may be a potential inflammatory biomarker playing an important role in the diagnosis and assessment of adhesion in endometriosis.

Oestrogen up-regulates DNMT1 and leads to the hypermethylation of RUNX3 in the malignant transformation of ovarian endometriosis.

RESEARCH QUESTION: What is the mechanism of hypermethylation of runt-related transcription factor 3 (RUNX3) in the eutopic endometrium of endometriosis as biomarker in the malignant transformation of endometriosis? DESIGN: Methylation-specific polymerase chain reaction was used to analyse the methylation status of RUNX3 in endometriosis-associated ovarian cancer (EAOC). Primary eutopic endometrial stromal cells (ESC) were isolated from the uteri of patients with ovarian endometriosis. After RUNX3 knockdown by RNA interference technology or ESC treated with oestradiol, the proliferation and invasion ability were evaluated in ESC by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and transwell assays. RESULTS: The frequency of methylation of RUNX3 in neoplastic tissue in the EAOC group was significantly higher than that in the ectopic endometrium of the endometriosis group (P < 0.001), and the frequency of methylation of RUNX3 in the eutopic endometrium of the EAOC group was significantly higher than that in the endometriosis group (P < 0.001). However, there was no significant difference in the eutopic endometrium when compared between the endometriosis group and the control endometrium group (P = 0.233). Silencing RUNX3 promoted the proliferation and invasion of ESC (P < 0.001 and P < 0.001). Following intervention with oestrogen, it was observed that the oestradiol group showed higher levels of RUNX3 methylation (P < 0.001) and DNA methyltransferase 1 (DNMT1) mRNA and protein expression (P < 0.001 and P < 0.001), and lower RUNX3 mRNA and protein expression when compared with the ESC group (P < 0.001 and P < 0.001). CONCLUSION: This study demonstrated that hypermethylation of the RUNX3 was related to the malignant transformation of endometriosis and that this process was related to corresponding changes in the eutopic endometrium. Furthermore, the 'oestrogen-DNMT1' signalling pathway may induce the hypermethylation of RUNX3 to promote the malignant transformation of endometriosis.

Identification of Claudin-6 as a Molecular Biomarker in Pan-Cancer Through Multiple Omics Integrative Analysis.

Claudin-6 (CLDN6) is one of the 27 family members of claudins and majorly involved in the tight junction and cell-to-cell adhesion of epithelial cell sheets, playing a significant role in cancer initiation and progression. To provide a more systematic and comprehensive dimension of identifying the diverse significance of CLDN6 in a variety of malignant tumors, we explored CLDN6 through multiple omics data integrative analysis, including gene expression level in pan-cancer and comparison of CLDN6 expression in different molecular subtypes and immune subtypes of pan-cancer, targeted protein, biological functions, molecular signatures, diagnostic value, and prognostic value in pan-cancer. Furthermore, we focused on uterine corpus endometrial carcinoma (UCEC) and further investigated CLDN6 from the perspective of the correlations with clinical characteristics, prognosis in different clinical subgroups, co-expression genes, and differentially expressed genes (DEGs), basing on discussing the validation of its established monoclonal antibody by immunohistochemical staining and semi-quantification reported in the previous study. As a result, CLDN6 expression differs significantly not only in most cancers but also in different molecular and immune subtypes of cancers. Besides, high accuracy in predicting cancers and notable correlations with prognosis of certain cancers suggest that CLDN6 might be a potential diagnostic and prognostic biomarker of cancers. Additionally, CLDN6 is identified to be significantly correlated with age, stage, weight, histological type, histologic grade, and menopause status in UCEC. Moreover, CLDN6 high expression can lead to a worse overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) in UCEC, especially in different clinical subgroups of UCEC. Taken together, CLDN6 may be a remarkable molecular biomarker for diagnosis and prognosis in pan-cancer and an independent prognostic risk factor of UCEC, presenting to be a promising molecular target for cancer therapy.

The role of YTH domain containing 2 in epigenetic modification and immune infiltration of pan-cancer.

YTH domain containing 2 (YTHDC2) is the largest N6-Methyladenosine (m6 A) binding protein of the YTH protein family and the only member containing ATP-dependent RNA helicase activity. For further analysing its biological role in epigenetic modification, we comprehensively explored YTHDC2 from gene expression, genetic alteration, protein-protein interaction (PPI) network, immune infiltration, diagnostic value and prognostic value in pan-cancer, using a series of databases and bioinformatic tools. We found that YTHDC2 with Missense mutation could cause a different prognosis in uterine corpus endometrial carcinoma (UCEC), and its different methylation level could lead to a totally various prognosis in adrenocortical carcinoma (ACC), cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), lung squamous cell carcinoma (LUSC) and UCEC. The main molecular mechanisms of YTHDC2 focused on catalytic activity, helicase activity, snRNA binding, spliceosome and mRNA surveillance. Additionally, YTHDC2 was notably correlated with tumour immune infiltration. Moreover, YTHDC2 had a high diagnostic value for seven cancer types and a prognostic value for brain lower grade glioma (LGG), rectum adenocarcinoma (READ) and skin cutaneous melanoma (SKCM). Collectively, YTHDC2 plays a significant role in epigenetic modification and immune infiltration and maybe a potential biomarker for diagnosis and prognosis in certain cancers.

Downregulation of SPOCK2 promotes the proliferation, adhesion, and invasion of endometrial epithelial cells.

PURPOSE: A previous study found that a lack of SPOCK2 expression was an early event that occurs during the malignant transformation of endometriosis (EMS); however, the role played by SPOCK2 in the pathogenesis of endometriosis and its malignant transformation remains unclear. MATERIALS AND METHODS: In this study, SPOCK2 expression in human endometrial epithelial cells (hEECs) was downregulated by transfection with shRNA, and the biological behavior of the transfected cells was observed. RESULTS: We found that downregulation of SPOCK2 promoted cell proliferation, adhesion, and invasion. CONCLUSIONS: Our data suggest that downregulation of SPOCK2 might participate in the pathogenesis and progression of EMS, as well as its malignant transformation, by promoting the proliferation, adhesion, and invasion of endometrial epithelial cells.

SPOCK2 Affects the Biological Behavior of Endometrial Cancer Cells by Regulation of MT1-MMP and MMP2.

Abnormal expression of SPARC (osteonectin), cwcv and kazal-like domains proteoglycan 2 (SPOCK2) plays a significant role in the development and progression of various human cancers, yet a relationship between SPOCK2 and endometrial cancer (EC) has not been reported. Here, we assessed the potential role and mechanism by which SPOCK2 acts in the pathogenesis and progression of EC. First, protein expression of SPOCK2 in EC tissue from patients was detected by immunohistochemistry and associated clinical data were analyzed. Then, HEC-1A and Ishikawa cells were transfected with an adenoviral vector containing an SPOCK2 recombinant fragment and the biological behavior of transfected cells was observed. Finally, the expression of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP2 in the transfected cells was detected by Western blot and zymography gel assay to analyze the effect of SPOCK2 on the regulation of the MT1-MMP/MMP2 pathway. We found that there was significantly less SPOCK2 protein expression in the EC tissue than in the normal endometrium tissue, and lack of SPOCK2 protein expression in EC tissue was associated with distant metastasis and myometrial invasion. Upregulation of SPOCK2 in HEC-1A and Ishikawa cells inhibited cell proliferation, invasion, adhesion, and apoptosis. Upregulation of SPOCK2 inhibited the expression of MT1-MMP and MMP2 and activation of MMP2 in HEC-1A and Ishikawa cells. Collectively, our data indicated that SPOCK2 contributed to the progression of EC by regulating the biological behavior of cancer cells, which is achieved partly through regulating protein expression of MT1-MMP and MMP2 and activation of MMP2.

SPOCK2 Affects the Biological Behavior of Endometrial Cancer Cells by Regulation of MT1-MMP and MMP2.

Abnormal expression of SPARC (osteonectin), cwcv and kazal-like domains proteoglycan 2 (SPOCK2) plays a significant role in the development and progression of various human cancers, yet a relationship between SPOCK2 and endometrial cancer (EC) has not been reported. Here, we assessed the potential role and mechanism by which SPOCK2 acts in the pathogenesis and progression of EC. First, protein expression of SPOCK2 in EC tissue from patients was detected by immunohistochemistry and associated clinical data were analyzed. Then, HEC-1A and Ishikawa cells were transfected with an adenoviral vector containing an SPOCK2 recombinant fragment and the biological behavior of transfected cells was observed. Finally, the expression of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP2 in the transfected cells was detected by Western blot and zymography gel assay to analyze the effect of SPOCK2 on the regulation of the MT1-MMP/MMP2 pathway. We found that there was significantly less SPOCK2 protein expression in the EC tissue than in the normal endometrium tissue, and lack of SPOCK2 protein expression in EC tissue was associated with distant metastasis and myometrial invasion. Upregulation of SPOCK2 in HEC-1A and Ishikawa cells inhibited cell proliferation, invasion, adhesion, and apoptosis. Upregulation of SPOCK2 inhibited the expression of MT1-MMP and MMP2 and activation of MMP2 in HEC-1A and Ishikawa cells. Collectively, our data indicated that SPOCK2 contributed to the progression of EC by regulating the biological behavior of cancer cells, which is achieved partly through regulating protein expression of MT1-MMP and MMP2 and activation of MMP2.

Accuracy of Physical Examination, Transvaginal Sonography, Magnetic Resonance Imaging, and Rectal Endoscopic Sonography for Preoperative Evaluation of Rectovaginal Endometriosis.

The aim of this study was to compare the effectiveness of physical examination, transvaginal sonography, magnetic resonance imaging, and rectal endoscopic sonography for the identification of rectovaginal endometriosis and potential rectal infiltration. Women with suspected rectovaginal endometriosis underwent physical examination, transvaginal sonography, magnetic resonance imaging, and rectal endoscopic sonography. Evaluation was performed for the presence of rectovaginal endometriotic foci and rectal infiltration. The findings obtained with these methods were compared with those of surgical and histopathological examination. Sensitivity, specificity, positive predictive values, and negative predictive values were evaluated for each method. Rectovaginal endometriosis was histologically confirmed in 21 (72.4%) of 29 women. With respect to diagnosis of rectovaginal endometriosis, the sensitivity, specificity, and accuracy of physical examination were 95.2%, 62.5%, and 86.2%; those of transvaginal sonography were 42.9%, 87.5%, and 55.2%; those of magnetic resonance imaging were 90.5%, 87.5%, and 89.7%; and those of rectal endoscopic sonography were 81.0%, 75.0%, and 79.3%, respectively. With respect to identification of rectal infiltration, the sensitivity, specificity, and accuracy of transvaginal sonography were 26.7%, 85.7%, and 55.2%; those of magnetic resonance imaging were 73.3%, 92.9%, and 82.8%; and those of rectal endoscopic sonography were 86.7%, 85.7%, and 86.2%, respectively. Magnetic resonance imaging combined with physical examination seem to be the main approach for the presurgical assessment of rectovaginal endometriosis. Rectal endoscopic sonography is a worthwhile method for the diagnosis of rectal infiltration.

Preoperative neutrophil-to-lymphocyte ratio is a predictor of survival of epithelial ovarian cancer: a systematic review and meta-analysis of observational studies.

Inflammation plays an important role in the development and progression of epithelial ovarian cancer (EOC). However, no meta-analysis has comprehensively and quantitatively investigated the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in EOC patients. Therefore, we performed a meta-analysis to quantify the prognostic impact of this biomarker. We searched the PubMed and Web of Science databases from their inception through December 31, 2016, and examined observational studies evaluating the association of preoperative NLR with progression-free survival (PFS) and overall survival (OS) of EOC patients. A random-effects model was used to summarize hazard ratios (HRs) with 95% confidence intervals (CIs). Twelve retrospective cohort studies including 3,154 EOC patients were identified. Elevated NLR in EOC patients was associated with worse PFS (summarized HR=1.80; 95% CI = 1.22-2.65; I2 = 79.1%) and OS (summarized HR = 1.72; 95% CI = 1.18-2.51; I2 = 73.5%) compared with low NLR. No evidence of publication bias was detected by funnel plot analysis and formal statistical tests. Although the results were robust in all subgroup analyses, not all results were statistically significant. We determined that adjustments for CA-125 level and performance status might be sources of heterogeneity. These combined results indicate that preoperative NLR is an important predictor of prognosis in EOC patients. Since the high heterogeneity and retrospective study design of included studies, these results require further validation with prospective cohort and trials enrolling larger patient populations and conducting longer follow-up examinations.

Inducing malignant transformation of endometriosis in rats by long-term sustaining hyperestrogenemia and type II diabetes.

This study aimed to induce malignant transformation of endometriosis in Sprague-Dawley rats by hyperestrogenemia and type II diabetes and evaluate its similarity with human disease in biological features. Rats with surgically induced endometriosis were randomized into two groups: those treated with estradiol (5 mg/kg three times/week after surgery), streptozotocin (25 mg/kg, 1 month after surgery), and high carbohydrate-and-fat feed (Es group); and those treated with placebo saline and standard feed (control group). All rats were randomly killed 2, 4, or 8 months after surgery. The endometriosis lesions and the corresponding eutopic endometria were subjected to morphological evaluation, TUNEL, and immunohistochemical analysis for the expressions of proliferating cell nuclear antigen, phosphatase and tensin homolog, phosphorylated protein kinase B, and phosphorylated mammalian target of rapamycin proteins. In the Es group, three cases (6.0%) of endometriosis showed atypical hyperplasia accompanied by simple hyperplastic eutopic endometria, and two cases (4.0%) of endometriosis showed endometrioid carcinoma accompanied by atypical hyperplastic eutopic endometria. In the Es group, the activity of organelles and the expressions of proliferating cell nuclear antigen, phosphorylated protein kinase B, and phosphorylated mammalian target of rapamycin increased, and the level of phosphatase and tensin homolog and TUNEL positivity decreased progressively in the order of endometriosis, atypical endometriosis, and malignant endometriosis. The same tendency was found in the corresponding eutopic endometria. The induced malignant endometriosis showed similarities with human disease in the pathological process and histomorphological and molecular biological features. The method is feasible. The malignant transformations of endometriosis and eutopic endometria may have correlations and similarities, but the former may suffer a higher risk of canceration.

Effect of LIM kinase 1 overexpression on behaviour of endometriosis-derived stromal cells.

LIM kinase 1 (LIMK1) has been implicated in tumour invasion and migration in several tumour types. However, its role in the progression of endometriosis has not yet been studied. Our aim is to analyse LIMK1 expression in endometriosis-derived stromal cells and to explore the effects of LIMK1 overexpression on their biological behaviour. The mRNA and protein expression levels of LIMK1 of eutopic endometrial stromal cells (ESCs) separated from 30 endometriosis patients and normal endometrial stromal cells (NSCs) separated from 30 patients without endometriosis were analysed by real-time polymerase chain reaction and Western blot. Lentiviral particles containing human LIMK1 short interfering RNA were used to silence the LIMK1 gene in ESCs and LIMK1-expressing lentiviral particles containing the total LIMK1 cDNA was transfected into NSCs to upregulate LIMK1 expression. Cell migration, invasion, proliferation and expression of markers of adhesion, invasion and angiogenesis of ESCs and NSCs were evaluated under basal conditions and after transfection in vitro. The mRNA and protein expression levels of LIMK1 in ESCs were higher than those in NSCs. Under basal conditions, ESCs exhibited greater cell migration, invasion and proliferation and higher levels of markers of adhesion, invasion and angiogenesis than NSCs. The behaviour of ESCs was decreased after LIMK1 gene silencing and that of NSCs was elevated after LIMK1 gene upregulation. Thus, LIMK1 is overexpressed in ESCs thereby facilitating malignant-like behaviour, including enhanced migration, invasion, proliferation and angiogenesis, all of which contribute to the occurrence and development of endometriosis.

RUNX3 is inactivated by promoter hypermethylation in malignant transformation of ovarian endometriosis.

The aim of the present study was to investigate the role of epigenetic inactivation of the runt-related transcription factor 3 gene (RUNX3) in the malignant transformation of ovarian endometriosis. Samples obtained by microdissection and scraping included 30 malignant ovarian endometriotic cyst tissues and 30 corresponding eutopic endometrium tissues from the endometriosis-associated ovarian carcinoma (EAOC) group, 19 benign ovarian endometriotic cyst tissues and 22 corresponding eutopic endometrium tissues from the endometriosis (EM) group and 22 normal eutopic endometrium tissues from the control endometrium (CE) group. RUNX3 methylation status was determined by methylation-specific PCR and bisulfite sequencing, while levels of RUNX3 and ERα protein expression were evaluated using immunohistochemistry. The percentage of RUNX3 methylation and negative RUNX3 protein expression in the malignant ovarian endometriotic cysts from the EAOC group was significantly higher than that in the benign ovarian endometriotic cysts from the EM group. The percentage of RUNX3 methylation and negative RUNX3 protein expression in the eutopic endometrium from the EAOC group was significantly higher than that in the EM and CE groups. An inverse correlation between positive RUNX3 protein expression and methylation was observed and a positive correlation was shown between RUNX3 methylation and ERα protein expression. In the malignant ovarian endometriotic cysts from the EAOC group, there was no significant correlation between methylation frequency of the RUNX3 gene and histological type. However, the percentage of RUNX3 gene methylation was significantly higher in the tissue samples from patients with surgical stage IC EAOC than the percentage in patients with stage IA and IB disease. These results suggest that RUNX3 inactivation by promoter hypermethylation plays a role in the progression of malignant transformation of ovarian EM and is closely related to estrogen metabolism. Negative protein expression and abnormal RUNX3 methylation in the eutopic endometrium could be used as diagnostic markers in patients with ovarian EM who may be at an increased risk of developing EAOC.