Non-hormonal targets underlying endometriosis: A focus on molecular mechanisms

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

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

Transcriptome Profiling of Eutopic and Ectopic Endometrial Stromal Cells in Women with Endometriosis Based on High-Throughput Sequencing

Endometriosis is a common gynecological disease that affects approximately 5–10% of reproductive-aged women. However, the etiology and pathophysiology of endometriosis are currently unclear. The objective of this study was to identify a potential pathogenic gene of endometriosis using RNA sequencing (RNA-seq) analysis. Human endometrial stromal cells were isolated from four patients receiving surgical treatment for endometriosis during laparoscopic surgery, and RNA-seq was used to examine differentially expressed genes (DEGs) in eutopic and ectopic endometrial stromal cells. The functional significance of the differentially expressed genes was analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. A total of 1309 upregulated and 663 downregulated genes were identified through the analysis of the transcriptomes of eutopic and ectopic endometrial stromal cells. Furthermore, KEGG analysis indicated that these DEGs were mainly enriched in the PI3K-Akt signaling pathway, cytokine–cytokine receptor interaction, and MAPK signaling pathway. Our study identified differential gene expression in eutopic as compared to ectopic endometrial tissue stromal cells. We strongly believe that our findings can bring new insights into the underlying mechanisms of endometriosis. However, future research is necessary to clarify the roles of the identified genes.

PI3K/AKT pathway is altered in the endometriosis patient's endometrium and presents differences according to severity stage

Based on the inflammatory nature and hormone-dependency of endometriosis, PI3K/AKT signaling appears to influence its progression. Could the endometriosis stages be linked to differential changes in PI3K/AKT pathway regulation? The objective is to evaluate the expression of PI3K, PTEN, AKT and p-AKT in endometrial human biopsies, according to the presence or absence of the disease, and to assess the underlying differences regarding the endometriosis stages. Biopsy specimens of the ectopic and eutopic endometrium were obtained from twenty women with untreated peritoneal endometriosis as well as endometrium biopsies from nine controls. Our study revealed an increased expression of PI3K in eutopic and ectopic endometrium from patients with endometriosis, and a reduced expression of PTEN and increased levels of AKT phosphorylation, compared to control endometrium. Both eutopic and ectopic endometrium from patients with minimal-mild endometriosis expressed a significant reduced PTEN level compared to the respective endometrium from patients with moderate-severe endometriosis. The ratio p-AKT/total AKT showed higher levels of AKT phosphorylation in endometriotic tissue from patients with minimal-mild endometriosis. This study has firmly confirmed the alteration in PI3K/AKT pathway regulation and demonstrated clear differences between the stages of endometriosis, emphasizing the importance of this pathway in the first stage of the disease.