Downregulation of Proline Hydroxylase 2 and Upregulation of Hypoxia-Inducible Factor 1α are Associated with Endometrial Cancer Aggressiveness

Mapping the expression and functional landscape of key enzymes in glucose metabolism within human gynecological tumors

Gynecological tumors, primarily ovarian cancer (OC), cervical cancer (CC), and endometrial cancer (EC), have a significant global impact on women's health, characterized by high mortality rates. Emerging evidence underscores the pivotal role of altered glucose metabolism in the initiation and progression of these malignancies. Glucose metabolism, encompassing glycolysis, the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, and the pentose phosphate pathway (PPP), among others, is intricately governed by a spectrum of key enzymes. These enzymes drive metabolic reprogramming essential for tumor growth and survival, thereby influencing patient outcomes and clinical management strategies. However, the comprehensive characterization and summary of the expression profiles, regulatory networks involved, and functional roles of these glucose metabolic enzymes in human gynecological tumors remain incomplete. In this review, we systematically map the expression landscape of these critical glucose metabolic enzymes in gynecological cancers based on research utilizing clinical gynecological tumor tissues. Additionally, we summarize the specific functions of key enzymes of glucose metabolism and the pathways they regulate in gynecological tumors. This review provides profound insights into the metabolic dynamics underlying these diseases. This understanding illuminates the metabolic strategies employed by tumor cells and sets the stage for innovative therapeutic approaches targeting cancer cell glucose metabolic dependencies, thereby holding promise for enhancing patient outcomes in gynecological oncology.

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.

EGLN1: A Biomarker of Poor Prognosis of Cervical Cancer and a Target of Treatment

Objective: To conduct bioinformatics analysis on the prognostic effect, mechanism of action, and drug sensitivity of Egl-9 family hypoxia-inducible factor 1 (EGLN1) expression on cervical cancer. Methods: Bioinformatics were obtained from Gene Expression Profiling Interactive Analysis (GEPIA), Tumor Immune Estimation Resource (TIMER), and the human cancer metastasis database (HCMDB), and the effect of EGLN1 expression level on the prognosis of cervical cancer was comprehensively analyzed. The protein-protein interaction network was constructed by Search Tool for the Retrieval of Interacting Genes/Proteins (STRING), and the possible mechanism of EGLN1 affecting the prognosis of cervical cancer was discussed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. In addition, Gene Set Cancer Analysis (GSCALite) was used to predict sensitive drugs online. Results: The higher the expression level of EGLN1, the shorter the tumor-free survival time and overall survival time of cervical cancer. The higher the stage of cervical cancer, the higher the expression level of EGLN1. The expression of EGLN1 affects the degree of immune infiltration, the variation of somatic copy number, and the level of N6-methyladenosine (m6A) modification in cervical cancer. COX regression model suggested that EGLN1 was an independent prognostic factor of cervical cancer. Conclusions: The high expression of EGLN1 in cervical cancer is an independent risk factor for the prognosis of cervical cancer, which affects the prognosis of cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) through different signal pathways. It is expected to be used to predict the sensitive anticancer drugs for the treatment of cervical cancer.

Determining the level of stromal and epithelial cells activity in normal and hyperplastic endometrium of late reproductive and perimenopausal women

Hyperplastic processes of the endometrium (HPE) are a group of benign endometrial and stromal cells that have undergone altered growth. This study aimed to investigate the potential role of hypoxia (as indicated by Hif-1α) and apoptosis markers (p53 and BCL-2) in the development of hyperplastic processes of the endometrium (HPE). Results showed that endometrial cells with atypical hyperplasia had increased levels of Hif-1ɑ, which indicates the presence of endometrial hypoxia and may trigger pathological manifestations. Though this result was not statistically significant, it could be the cause of atypia hyperplasia in the late reproductive period (Hif-1ɑ=1.89±0.09 units) and the perimenopausal period (Hif-1ɑ=2.09±0.07 units). Additionally, the study found that p53 markers were elevated in epithelial cells in the late reproductive period, and similar patterns were observed in the perimenopausal period, with the biggest expression in atypical hyperplasia. The study also found that the high expression of BCL-2 indicator (+++) was less common in late reproductive period women with atypia than those without it (χ²=7.2 p=0.01). A similar situation was observed in women in the perimenopausal period (χ²=4.2 p=0.04). These findings suggest that hypoxia may play a role in the development of HPE, as well as changes in apoptotic markers present in the endometrial tissue.

JAK1 inactivation promotes proliferation and migration of endometrial cancer cells via upregulating the hypoxia-inducible factor signaling pathway

BACKGROUND

Loss-of-function (LOF) mutations of JAK1, a member of the JAK kinase family, were frequently observed in EC, indicating that JAK1 may act as a tumor suppressor, at least in EC. However, the mechanism of JAK1 mediated regulation of tumorigenesis remains poorly understood.

METHODS

The genetic alterations of JAK1 in EC using latest sequencing dataset of EC deposited in TCGA database. The RNA-Seq dataset of EC and normal endometrial tissues from TCGA cohort was analyzed. The expression of JAK1 in EC and normal endometrial tissues were investigated using immunohistochemistry. The expression levels of genes in endometrial cancer cells were detected by quantitative reverse transcription-PCR (RT-qPCR) and western blotting. JAK1 protein was efficiently depleted by the two shRNAs. HIF1/2-α protein was efficiently depleted by siRNAs. JAK1 overexpressed EC cells were generated by an expressing plasmid. The proliferation and migration ability of cancer cells were evaluated by CCK8, colony formation assays and transwell assays. The global transcriptomic changes in JAK1-depleted KLE cells were investigated using RNA-Seq. Gene Ontology (GO) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to identify the most significant pathways that were altered in JAK1-depleted KLE cells. The physical association between HIF-1/2α and JAK1 using co-immunoprecipitation (co-IP) assays.

RESULTS

In the present study, we found that JAK1 was frequently mutated and downregulated in EC. JAK1 knockdown promotes EC cell proliferation and migration. JAK1 overexpression reduces EC cell proliferation and migration. We examined the transcriptional profiling changes in JAK1-depleted EC cells and unexpectedly found that the hypoxia inducible factor (HIF) pathway was activated. Mechanistically, JAK1 interacts with HIF-1/2α, and reduces HIF1/2-α protein expression under hypoxia. HIF-1/2α knockdown reverses the JAK1 knockdown-induced growth and migration of EC cells under hypoxia. JAK1 knockdown or pharmacological inhibition of JAK1 kinase activity by Ruxolitinib upregulates transcription of HIF target genes under hypoxia. JAK1 overexpression downregulates transcription of HIF target genes under hypoxia.

CONCLUSIONS

These findings provide novel insights into the functional link between JAK1 LOF mutations and abnormal HIF pathway activation in EC and suggest that pharmacological inhibition of HIF1/2 represents a promising therapeutic strategy targeting JAK1-mutated ECs. Video Abstract.

Human umbilical cord blood mesenchymal stem cells-derived exosomal microRNA-503-3p inhibits progression of human endometrial cancer cells through downregulating MEST

Endometrial cancer (EC) is a group of epithelial malignant tumors that occur in the endometrium. The specific pathogenesis is not revealed, hence, the goal of this study was to investigate the influence of human umbilical cord blood mesenchymal stem cells (hUMSCs)-derived exosomal microRNA-503-3p (miR-503-3p) on human EC cells by mediating mesoderm-specific transcript (MEST). The binding relationship between MiR-503-3p and MEST was searched. HUMSCs were collected and exosomes (Exos) were isolated and identified. Human EC cell lines HEC-1B and RL95-2 were transfected with elevated miR-503-3p or silenced MEST vector or co-cultured with Exos to figure their roles in biological functions of EC cells. The in vitro effect of miR-503-3p, MEST, and Exos on EC cells was further verified in vivo. MEST was a target of miR-503-3p. Overexpression of miR-503-3p or reduction of MEST suppressed the biological functions of EC cells. Enhanced MEST expression mitigated the role of upregulated miR-503-3p on the growth of EC cells. HUMSCs-derived Exos suppressed EC cell growth, upregulated miR-503-3p-modified HUMSCs-derived Exos had a more obvious inhibitory effect on EC cell growth. The anti-tumor effect of elevated miR-503-3p, silenced MEST, and HUMSCs-derived Exos were verified in nude mice. This study highlights that hUMSCs-derived exosomal miR-503-3p inhibits EC development by suppressing MEST, which is of great benefit to EC therapy.

The non-canonical functions of HIF prolyl hydroxylases and their dual roles in cancer

The hypoxia-inducible factor (HIF) prolyl hydroxylases (PHDs) are dioxygenases using oxygen and 2-oxoglutarate as co-substrates. Under normoxia, PHDs hydroxylate the conserved prolyl residues of HIFα, leading to HIFα degradation. In hypoxia PHDs are inactivated, which results in HIFα accumulation. The accumulated HIFα enters nucleus and initiates gene transcription. Many studies have shown that PHDs have substrates other than HIFα, implying that they have HIF-independent non-canonical functions. Besides modulating protein stability, the PHDs-mediated prolyl hydroxylation affects protein-protein interaction and protein activity for alternative substrates. Increasing evidence indicates that PHDs also have hydroxylase-independent functions. They influence protein stability, enzyme activity, and protein-protein interaction in a hydroxylase-independent manner. These findings highlight the functional diversity and complexity of PHDs. Due to having inhibitory activity on HIFα, PHDs are proposed to act as tumor suppressors. However, research shows that PHDs exert either tumor-promoting or tumor-suppressing features. Here, we try to summarize the current understanding of PHDs hydroxylase-dependent and -independent functions and their roles in cancer.

The role of hypoxia in endometrial cancer

Endometrial cancer represents the most frequent neoplasia from the corpus uteri, and comprises the 14th leading cause of death in women worldwide. Risk factors that contribute to the disease include early menarche, late menopause, nulliparity, and menopausal hormone use, as well as hypertension and obesity comorbidities. The clinical effectiveness of chemotherapy is variable, suggesting that novel molecular targeted therapies against specific cellular processes associated with the maintenance of cancer cell survival and therapy resistance urged to ameliorate the rates of success in endometrial cancer treatment. In the course of tumor growth, cancer cells must adapt to decreased oxygen availability in the microenvironment by upregulation of hypoxia-inducible factors, which orchestrate the activation of a transcriptional program leading to cell survival. During this adaptative process, the hypoxic cancer cells may acquire invasive and metastatic properties as well as increased cell proliferation and resistance to chemotherapy, enhanced angiogenesis, vasculogenic mimicry, and maintenance of cancer cell stemness, which contribute to more aggressive cancer phenotypes. Several studies have shown that hypoxia-inducible factor 1 alpha (HIF-1α) protein is aberrantly overexpressed in many solid tumors from breast, prostate, ovarian, bladder, colon, brain, and pancreas. Thus, it has been considered an important therapeutic target. Here, we reviewed the current knowledge of the relevant roles of cellular hypoxia mechanisms and HIF-1α functions in diverse processes associated with endometrial cancer progression. In addition, we also summarize the role of microRNAs in the posttranscriptional regulation of protein-encoding genes involved in the hypoxia response in endometrial cancer. Finally, we pointed out the need for urgent targeted therapies to impair the cellular processes activated by hypoxia in the tumor microenvironment.

Prognostic and Clinicopathological Significance of Hypoxia-Inducible Factor-1α in Endometrial Cancer: A Meta-Analysis

Background

Current reports on the prognostic and predictive value of hypoxia-inducible factor-1α (HIF-1α) in endometrial carcinoma are inconsistent. Therefore, we conducted this meta-analysis to precisely evaluate the association of HIF-1α expression with susceptibility, clinical features, and prognosis of endometrial cancer.

Methods

Eligible studies that assessed the role of HIF-1α protein expression, immunohistochemistry detection, disease susceptibility, clinical features, and prognosis of endometrial cancer were searched from the Embase, Pubmed, and Web of Science databases. Stata 14.0 software was used to merge and compute pooled hazard ratios (HR) and odds ratios (OR). Information including HIF-1α protein expression and clinical progression of endometrial cancer was extracted. The pooled HR and OR with corresponding 95% confidence intervals (CI) were used to estimate the strength of these associations.

Results

A total of 25 studies were included in the analysis. HIF-1α protein expression in endometrial cancer tissue was significantly higher than that in normal tissues (OR = 15.79, 95% CI = 8.44–29.52, P < 0.05). Endometrial cancer patients with higher HIF-1α protein expression had poorer prognosis compared to patients with low HIF-1α protein expression (HR = 2.29, 95% CI = 1.68–2.90, P < 0.05). In addition, high HIF-1α protein expression was significantly associated with endometrial cancer grade, lymph node metastasis, and myometrial invasion (grade in Caucasians: OR = 3.09, 95% CI = 1.63–5.85, P < 0.05; lymph node metastasis: OR = 3.09, 95% CI = 1.63–5.85, P < 0.05; myometrial invasion: OR = 2.26, 95% CI = 2.15–5.08, P < 0.05).

Conclusions

HIF-1α overexpression was significantly associated with increased risk, advanced clinical progression, and poor prognosis in endometrial cancer patients.

Endometrial Cancer Cells Promote M2-Like Macrophage Polarization by Delivering Exosomal miRNA-21 under Hypoxia Condition

Increasing evidence has demonstrated that hypoxia was an aggressive feature in endometrial cancer (EC), which is significantly associated with the tumor grade, lymph node metastasis, and tumor resistance to chemotherapy. However, the relationship between hypoxia and the immune microenvironment in EC is not very clear. Exosomes are small membrane vesicles secreted from a variety of cell types which mediate cell-to-cell communication through transported biomolecules. Here, we investigated whether exosomes can play an immunomodulatory role in intercellular communication between EC cells and macrophages. EC KEL cells were cultured under hypoxia or normoxic condition to collect exosomes. After identification, the exosomes derived from hypoxic or normoxic KEL cells were cultured with the monocyte cell line THP-1 to study the immunoregulation function of KEL cells. The results showed that the total number of exosomes produced by hypoxic KEL cells was significantly higher than that in normoxic condition. In addition, hypoxia markedly stimulated the increase in miRNA-21 expression in the exosomes. After coculture, we found that exosomal miRNA-21 could be horizontally transferred into THP-1 cells. And then, the notably enhanced mRNA expression levels of IL-10 and CD206 in THP-1 cells were observed, suggestive of M2 polarization. To further study the effect of miRNA-21-containing exosomes, we transfected miRNA-21 mimics or inhibitor into THP-1 cells. The results showed that miRNA-21 mimics promoted IL-10 and CD206 mRNA expression levels, and the miRNA-21 inhibitor significantly prevented the alteration induced by intake of hypoxic KEL cell-derived exosomes. In summary, we found that endometrial cancer KEL cells in hypoxic condition promoted monocyte THP-1 cell transformation to M2-like polarization macrophages through delivering exosomal miRNA-21, which may be a potential mechanism of the formation of the immune microenvironment in EC progression.