Endometrial Cancer Stem Cells: Role, Characterization and Therapeutic Implications

The Endometrial Stem/Progenitor Cells and Their Niches

Endometrial stem/progenitor cells are a type of stem cells with the ability to self-renew and differentiate into multiple cell types. They exist in the endometrium and form niches with their neighbor cells and extracellular matrix. The interaction between endometrial stem/progenitor cells and niches plays an important role in maintaining, repairing, and regenerating the endometrial structure and function. This review will discuss the characteristics and functions of endometrial stem/progenitor cells and their niches, the mechanisms of their interaction, and their roles in endometrial regeneration and diseases. Finally, the prospects for their applications will also be explored.

Cell surface CD55 traffics to the nucleus leading to cisplatin resistance and stemness by inducing PRC2 and H3K27 trimethylation on chromatin in ovarian cancer

BACKGROUND

Platinum resistance is the primary cause of poor survival in ovarian cancer (OC) patients. Targeted therapies and biomarkers of chemoresistance are critical for the treatment of OC patients. Our previous studies identified cell surface CD55, a member of the complement regulatory proteins, drives chemoresistance and maintenance of cancer stem cells (CSCs). CSCs are implicated in tumor recurrence and metastasis in multiple cancers.

METHODS

Protein localization assays including immunofluorescence and subcellular fractionation were used to identify CD55 at the cell surface and nucleus of cancer cells. Protein half-life determinations were used to compare cell surface and nuclear CD55 stability. CD55 deletion mutants were generated and introduced into cancer cells to identify the nuclear trafficking code, cisplatin sensitivity, and stem cell frequency that were assayed using in vitro and in vivo models. Detection of CD55 binding proteins was analyzed by immunoprecipitation followed by mass spectrometry. Target pathways activated by CD55 were identified by RNA sequencing.

RESULTS

CD55 localizes to the nucleus of a subset of OC specimens, ascites from chemoresistant patients, and enriched in chemoresistant OC cells. We determined that nuclear CD55 is glycosylated and derived from the cell surface pool of CD55. Nuclear localization is driven by a trafficking code containing the serine/threonine (S/T) domain of CD55. Nuclear CD55 is necessary for cisplatin resistance, stemness, and cell proliferation in OC cells. CD55 S/T domain is necessary for nuclear entry and inducing chemoresistance to cisplatin in both in vitro and in vivo models. Deletion of the CD55 S/T domain is sufficient to sensitize chemoresistant OC cells to cisplatin. In the nucleus, CD55 binds and attenuates the epigenetic regulator and tumor suppressor ZMYND8 with a parallel increase in H3K27 trimethylation and members of the Polycomb Repressive Complex 2.

CONCLUSIONS

For the first time, we show CD55 localizes to the nucleus in OC and promotes CSC and chemoresistance. Our studies identify a therapeutic mechanism for treating platinum resistant ovarian cancer by blocking CD55 nuclear entry.

Influence of Aldehyde Dehydrogenase Inhibition on Stemness of Endometrial Cancer Stem Cells

Endometrial cancer is one of the most common gynaecological malignancies. Although often diagnosed at an early stage, there is a subset of patients with recurrent and metastatic disease for whom current treatments are not effective. Cancer stem cells (CSCs) play a pivotal role in triggering tumorigenesis, disease progression, recurrence, and metastasis, as high aldehyde dehydrogenase (ALDH) activity is associated with invasiveness and chemotherapy resistance. Therefore, this study aimed to evaluate the effects of ALDH inhibition in endometrial CSCs. ECC-1 and RL95-2 cells were submitted to a sphere-forming protocol to obtain endometrial CSCs. ALDH inhibition was evaluated through ALDH activity and expression, sphere-forming capacity, self-renewal, projection area, and CD133, CD44, CD24, and P53 expression. A mass spectrometry-based proteomic study was performed to determine the proteomic profile of endometrial cancer cells upon N,N-diethylaminobenzaldehyde (DEAB). DEAB reduced ALDH activity and expression, along with a significant decrease in sphere-forming capacity and projection area, with increased CD133 expression. Additionally, DEAB modulated P53 expression. Endometrial cancer cells display a distinct proteomic profile upon DEAB, sharing 75 up-regulated and 30 down-regulated proteins. In conclusion, DEAB inhibits ALDH activity and expression, influencing endometrial CSC phenotype. Furthermore, ALDH18A1, SdhA, and UBAP2L should be explored as novel molecular targets for endometrial cancer.

Targeting Galectin 3 illuminates its contributions to the pathology of uterine serous carcinoma

BACKGROUND

Uterine serous cancer (USC) comprises around 10% of all uterine cancers. However, USC accounts for approximately 40% of uterine cancer deaths, which is attributed to tumor aggressiveness and limited effective treatment. Galectin 3 (Gal3) has been implicated in promoting aggressive features in some malignancies. However, Gal3's role in promoting USC pathology is lacking.

METHODS

We explored the relationship between LGALS3 levels and prognosis in USC patients using TCGA database, and examined the association between Gal3 levels in primary USC tumors and clinical-pathological features. CRISPR/Cas9-mediated Gal3-knockout (KO) and GB1107, inhibitor of Gal3, were employed to evaluate Gal3's impact on cell function.

RESULTS

TCGA analysis revealed a worse prognosis for USC patients with high LGALS3. Patients with no-to-low Gal3 expression in primary tumors exhibited reduced clinical-pathological tumor progression. Gal3-KO and GB1107 reduced cell proliferation, stemness, adhesion, migration, and or invasion properties of USC lines. Furthermore, Gal3-positive conditioned media (CM) stimulated vascular tubal formation and branching and transition of fibroblast to cancer-associated fibroblast compared to Gal3-negative CM. Xenograft models emphasized the significance of Gal3 loss with fewer and smaller tumors compared to controls. Moreover, GB1107 impeded the growth of USC patient-derived organoids.

CONCLUSION

These findings suggest inhibiting Gal3 may benefit USC patients.

The prognostic value of co-expression of stemness markers CD44 and CD133 in endometrial cancer

Objective

The purpose of this study was to investigate the correlation between stemness markers (CD44 and CD133) and clinical pathological features, and to further explore the prognostic value of co-expression of CD44 & CD133 in endometrial cancer (EC).

Methods

Clinical data of stage I-III EC patients who underwent initial surgical treatment at two large tertiary medical centers from 2015 to 2020 were retrospectively collected. Cohen's kappa coefficient was used to show the consistency of the expression between CD44 and CD133. The correlation between co-expression of CD44 & CD133 and prognosis of EC patients was explored using univariate and multivariate Cox regression analysis. Then, the prognosis models for early-stage (stage I-II) EC patients were constructed. Finally, stratified analysis was performed for EC patients in high-intermediate-risk and high-risk groups, Kaplan-Meier analysis was used to compare the survival differences between patients with and without adjuvant therapy in different co-expression states (low expression, mixed expression, high expression) of CD44 & CD133.

Results

A total of 1168 EC patients were included in this study. The consistency of the expression between CD44 and CD133 was 70.5%, the kappa coefficient was 0.384. High expression of CD44 & CD133 was associated with early FIGO stage (P=0.017), superficial myometrial invasion (P=0.017), and negative lymphatic vessel space invasion (P=0.017). Cox regression analysis showed that the co-expression of CD44 & CD133 was significantly correlated with the prognosis of early-stage (stage I-II) patients (P=0.001 for recurrence and P=0.005 for death). Based on this, the nomogram models were successfully constructed to predict the prognosis of early-stage EC patients. Meanwhile, Kaplan-Meier analysis showed that patients with adjuvant therapy had a better overall prognosis than those without adjuvant therapy in high-intermediate-risk and high-risk groups. However, there was no statistically significant difference in survival between patients with and without adjuvant therapy in high expression of CD44 & CD133 group (P=0.681 for recurrence, P=0.621 for death).

Conclusion

High expression of CD44 & CD133 was closely related to the adverse prognosis of early-stage EC patients. Meanwhile, patients with high expression of CD44 & CD133 may not be able to achieve significant survival benefits from adjuvant therapy.

Loss of EIF4G2 mediates aggressiveness in distinct human endometrial cancer subpopulations with poor survival outcome in patients

The non-canonical translation initiation factor EIF4G2 plays essential roles in cellular stress responses via translation of selective mRNA cohorts. Currently there is limited and conflicting information regarding its involvement in cancer development and progression. Here we assessed its role in endometrial cancer (EC), in a cohort of 280 EC patients across different types, grades, and stages, and found that low EIF4G2 expression highly correlated with poor overall- and recurrence-free survival in Grade 2 EC patients, monitored over a period of up to 12 years. To establish a causative connection between low EIF4G2 expression and cancer progression, we stably knocked-down EIF4G2 in two human EC cell lines in parallel. EIF4G2 depletion resulted in increased resistance to conventional therapies and increased the prevalence of molecular markers for aggressive cell subsets, altering their transcriptional and proteomic landscapes. Prominent among the proteins with decreased abundance were Kinesin-1 motor proteins, KIF5B and KLC1, 2, 3. Multiplexed imaging of the EC patient tumor cohort showed a correlation between decreased expression of the kinesin proteins, and poor survival in patients with tumors of certain grades and stages. These findings reveal potential novel biomarkers for Grade 2 EC with ramifications for patient stratification and therapeutic interventions.

LGR5, a prognostic stem cell target, promotes endometrial cancer proliferation through autophagy activation

Endometrial cancer (EC) is a common malignant tumor in women worldwide. Although early EC has a good prognosis, advanced endometrial cancer is still associated with the risk of drug resistance and recurrence. Cancer stem cells (CSCs), a category closely related to drug resistance and recurrence, are rarely studied at present. Here, we constructed a risk model containing ten stemness-related prognostic genes. Compared with patients in the low-risk group, patients in the high-risk group had a shorter overall survival time. The accuracy of this model was verified by ROC in the TCGA (AUC = 0.779) and Peking University People's Hospital (PKUPH, AUC = 0.864) cohorts. The risk score and stage were independent risk factors in the multivariate regression analysis, which was subsequently used to construct the nomogram and verified in the TCGA cohort. LGR5 was significantly correlated with overall survival and involvement in the Wnt signaling pathway. In addition, LGR5 was highly expressed in EC tissues and was related to age, stage, histological type, and menopause status in the TCGA database. Overexpression of LGR5 accelerated the proliferation rate of EC cells, which may be related to autophagy activation. Taken together, our study established a prognostic model based on transcription sequencing data from the TCGA database and verified it in the PKUPH cohort, which has prospective clinical implications for the prognostic evaluation of EC. We systematically studied the code gene LGR5 in EC, which may help clinicians make personalized prognostic assessments and effective clinical decisions for EC.

Identification of stemness subtypes and features to improve endometrial cancer treatment using machine learning

Endometrial cancer is one of the most common malignant tumours in women, and cancer stem cells are known to play an important role in its growth, invasion, metastasis, and drug resistance. Immunotherapy for endometrial cancer is still under research. In this study, a total of 547 endometrial cancer cases were randomly divided into training set (351 cases) set and test set (196 cases). The stemness index of patients was calculated using the One-Class Logistic Regression (OCLR) machine learning algorithm to explore the clinicopathological differences between index levels. Stemness subtypes were determined according to the characteristics of cancer stemness and their clinicopathological characteristics, immune features, and therapeutic effects were described. Our study suggests that endometrial cancer is classified into two stemness subtypes. Stemness subtypes, which are associated with its clinical features, may be independent prognostic factors for endometrial cancer. The stemness subtypes differed significantly in immune activity, immune cell infiltration, and the immune microenvironment, including sensitivity to chemotherapeutic drugs and potential therapeutic compounds. Algorithms were utilised to construct a stemness subtype prediction model and predictor. These findings will provide guidance for the clinical diagnosis, treatment, and prognosis of endometrial cancer.

MicroRNA Landscape in Endometrial Carcinomas in an Asian population: Unraveling Subtype-Specific Signatures

MicroRNAs (MiRNAs) are small, non-coding RNA molecules that function in RNA silencing and post-transcriptional regulation of gene expression. We analyzed the differential expression of miRNAs in 119 endometrial carcinomas, measuring their expression in histological subtypes, molecular subtypes, and tumors with CTNNB1 mutations. Tumors were subdivided into histological and molecular subtypes as defined by The Cancer Genome Atlas. The expression levels of 352 miRNAs were quantified using the PanoramiR panel. Mir-449a, mir-449b-5p, and mir-449c-5p were the top three miRNAs showing increased expression in both endometrioid and de-differentiated carcinomas but were not significantly increased in serous and clear cell carcinomas. The miRNAs with the most increased expression in serous and clear cell carcinomas were miR-9-3p and miR-375, respectively. We also identified 62 differentially expressed miRNAs among different molecular subtypes. Using sequential forward selection, we built subtype classification models for some molecular subtypes of endometrial carcinoma, comprising 5 miRNAs for MMR-deficient tumors, 10 miRNAs for p53-mutated tumors, and 3 miRNAs for CTNNB1-mutated tumors, with areas under curves of 0.75, 0.85, and 0.78, respectively. Our findings confirm the differential expression of miRNAs between various endometrial carcinoma subtypes and may have implications for the development of diagnostic and prognostic tools.

YAP1 affects the prognosis through the regulation of stemness in endometrial cancer

Background

Endometrial cancer stem-like cells (ECSCs) have been proven to be responsible for recurrence, metastasis, and drug-resistance in patients with endometrial cancer. The HIPPO pathway has been shown to play an important role in the development and maintenance of stemness in a variety of tumors. While there was less research about its function in ECSCs. The aim of this study was to explore the role of YAP1, a core molecular of HIPPO pathway, in the stemness of endometrial cancer and to reveal its influence on prognosis.

Methods

We collected specimens and clinical data from 774 patients with endometrial cancer to analyze the correlation between YAP1 expression and prognosis. We then examined the expression of YAP1 in ECSCs and EC cell lines (Ishikawa; HEC1-A) in vitro experiments. Changes in the stemness of cell lines were detected after YAP1 silencing by siRNA. Finally, high-throughput sequencing was used to predict the potential molecular interactions and mechanisms of YAP1's effect on stemness.

Result

Down-regulation of YAP1 significantly suppresses the stemness of EC cell lines. High expression of YAP1 leads to poor prognosis in EC by regulation of stemness.

Conclusion

YAP1 plays an important role in the prognosis of patients with EC by regulation of stemness.

New insights for gynecological cancer therapies: from molecular mechanisms and clinical evidence to future directions

Advanced and recurrent gynecological cancers lack effective treatment and have poor prognosis. Besides, there is urgent need for conservative treatment for fertility protection of young patients. Therefore, continued efforts are needed to further define underlying therapeutic targets and explore novel targeted strategies. Considerable advancements have been made with new insights into molecular mechanisms on cancer progression and breakthroughs in novel treatment strategies. Herein, we review the research that holds unique novelty and potential translational power to alter the current landscape of gynecological cancers and improve effective treatments. We outline the advent of promising therapies with their targeted biomolecules, including hormone receptor-targeted agents, inhibitors targeting epigenetic regulators, antiangiogenic agents, inhibitors of abnormal signaling pathways, poly (ADP-ribose) polymerase (PARP) inhibitors, agents targeting immune-suppressive regulators, and repurposed existing drugs. We particularly highlight clinical evidence and trace the ongoing clinical trials to investigate the translational value. Taken together, we conduct a thorough review on emerging agents for gynecological cancer treatment and further discuss their potential challenges and future opportunities.

The association of Wnt-signalling and EMT markers with clinical characteristics in women with endometrial cancer

Endometrial cancer is the most common gynecologic malignancy in the developed world. Risk stratification and treatment approaches are changing due to better understanding of tumor biology. Upregulated Wnt signaling plays an important role in cancer initiation and progression with promising potential for development of specific Wnt inhibitor therapy. One of the ways in which Wnt signaling contributes to progression of cancer, is by activating epithelial-to-mesenchymal transition (EMT) in tumor cells, causing the expression of mesenchymal markers, and enabling tumor cells to dissociate and migrate. This study analyzed the expression of Wnt signaling and EMT markers in endometrial cancer. Wnt signaling and EMT markers were significantly correlated with hormone receptors status in EC, but not with other clinico-pathological characteristics. Expression of Wnt antagonist, Dkk1 was significantly different between the ESGO-ESTRO-ESP patient risk assessment categories using integrated molecular risk assessment.

KIF4A promotes genomic stability and progression of endometrial cancer through regulation of TPX2 protein degradation

Kinesin family member 4A (KIF4A) belongs to the kinesin superfamily proteins, which are closely associated with mitophagy. Nonetheless, the role of KIF4A in endometrial cancer (EC) remains poorly characterized. The present study showed that KIF4A not only was upregulated but also predicted poor prognosis in patients with EC. KIF4A knockdown in EC cells resulted in attenuated proliferative capacity in vitro and in vivo. Transcriptome sequencing and gene function analysis revealed that KIF4A contributed to the maintenance of EC cells' genomic stability and that KIF4A knockdown induced the DNA damage response, cell cycle arrest, and apoptosis. Mechanistically, KIF4A interacted with TPX2 (a protein involved in DNA damage repair to cope with the replication pressure) to enhance its stability via inhibition of TPX2 ubiquitination and eventually ensured the genomic stability of EC cells during mitosis. Taken together, our results indicated that KIF4A functions as a tumor oncogene that facilitates EC progression via the maintenance of genomic stability. Therefore, targeting the KIF4A/TPX2 axis may provide new concepts and strategies for the treatment of patients with EC.

Role of Hyaluronic Acid in Selected Malignant Neoplasms in Women

Hyaluronic acid (HA) is a significant glycosaminoglycan component of the extracellular matrix, playing an essential role in cell localization and proliferation. However, high levels of HA may also correlate with multidrug resistance of tumor cells, an increased tendency to metastasize, or cancer progression, and thus represent a very unfavorable prognosis for cancer patients. The purpose of this review article is to summarize the results of studies describing the relationship between HA, the main ligand of the CD44 receptor, or other components of the HA signaling pathway. In addition, we review the course of selected female malignancies, i.e., breast, cervical, endometrial, and ovarian cancer, with the main focus on the mechanisms oriented to CD44. We also analyze reports on the beneficial use of HA-containing preparations in adjuvant therapy among patients with these types of cancer. Data from the literature suggest that HA and its family members may be critical prognostic biomarkers of selected malignancies among women. Nevertheless, the results of the available studies are inconclusive, and the actual clinical significance of HA expression analysis is still quite enigmatic. In our opinion, the HA-CD44 signaling pathway should be an attractive target for future research related to targeted therapy in gynecological cancers.

Oct-4 induces cisplatin resistance and tumor stem cell-like properties in endometrial carcinoma cells

OBJECTIVE

Research has suggested that tumor-initiating tumor stem cells are derived from normal stem cells and that tumor cells undergo progressive de-differentiation to achieve a stem cell-like state. Tumor stem cells are characterized by high proliferation ability, high plasticity, expression of multi-drug resistance proteins, and the ability to seed new tumors. Octamer-binding transcription factor 4 (Oct-4) and its activation targets are overexpressed in the tumor stem cells of various types of tumors, and this expression is associated with the pathogenesis, development, and poor prognosis of tumors. The primary objective of this study was to test if a stably transfected with Oct-4 gene cell line, RL95-2/Oct-4, has the characteristics of tumor stem cells.

MATERIALS AND METHODS

Human endometrial carcinoma cells (RL95-2) were transfected with a plasmid carrying genes for Oct-4 and green fluorescent protein (GFP). The stably transfected cells, RL95-2/Oct-4, were selected using G418 and observed to express the GFP reporter gene under the control of the Oct-4 promoter. GFP expression levels of RL95-2/Oct-4 cells were measured using flow cytometry. The proliferation potential of cells was determined according to cumulative population doubling and colony-formation efficiency. Gene expression was analyzed using reverse transcription-polymerase chain reaction.

RESULTS

RL95-2/Oct-4 cells not only exhibited increased expression of the three most important stem cell genes, Oct-4, Nanog, and Sox2, but also had increased expression of the endometrial tumor stem cell genes CD133 and ALDH1. Furthermore, enhanced expression of these genes in the RL95-2/Oct-4 cells was associated with higher colony-forming ability and growth rate than in parental RL95-2 cells. We also observed that cisplatin induced less cell death in RL95-2/Oct-4 cells than in RL95-2 cells, indicating that RL95-2/Oct-4 cells were more resistant to chemotherapeutic agents.

CONCLUSION

The study findings contribute to investigate the effects of Oct-4 on tumor stem cell origins.

Preparation and In Vitro Osteogenic Evaluation of Biomimetic Hybrid Nanocomposite Scaffolds Based on Gelatin/Plasma Rich in Growth Factors (PRGF) and Lithium-Doped 45s5 Bioactive Glass Nanoparticles

Bone tissue engineering is an emerging technique for repairing large bone lesions. Biomimetic techniques expand the use of organic-inorganic spongy-like nanocomposite scaffolds and platelet concentrates. In this study, a biomimetic nanocomposite scaffold was prepared using lithium-doped bioactive-glass nanoparticles and gelatin/PRGF. First, sol-gel method was used to prepare bioactive-glass nanoparticles that contain 0, 1, 3, and 5%wt lithium. The lithium content was then optimized based on antibacterial and MTT testing. By freeze-drying, hybrid scaffolds comprising 5, 10, and 20% bioglass were made. On the scaffolds, human endometrial stem cells (hEnSCs) were cultured for adhesion (SEM), survival, and osteogenic differentiation. Alkaline phosphatase activity and osteopontin, osteocalcin, and Runx2 gene expression were measured. The effect of bioactive-glass nanoparticles and PRGF on nanocomposites' mechanical characteristics and glass-transition temperature (T _g) was also studied. An optimal lithium content in bioactive glass structure was found to be 3% wt. Nanoparticle SEM examination indicated grain deformation due to different sizes of lithium and sodium ions. Results showed up to 10% wt bioactive-glass and PRGF increased survival and cell adhesion. Also, Hybrid scaffolds revealed higher ALP-activity and OP, OC, and Runx2 gene expression. Furthermore, bioactive-glass has mainly increased ALP-activity and Runx2 expression, whereas PRGF increases the expression of OP and OC genes. Bioactive-glass increases scaffold modulus and T _g continuously. Hence, the presence of both bioactive-glass and nanocomposite scaffold improves the expression of osteogenic differentiation biomarkers. Subsequently, it seems that hybrid scaffolds based on biopolymers, Li-doped bioactive-glass, and platelet extracts can be a good strategy for bone repair.

Intraoperative Flow Cytometry for the Characterization of Gynecological Malignancies

Simple Summary

Aneuploidy and high proliferative potential are distinct features of neoplastic cells. Based on the established role of intraoperative flow cytometry in various types of cancer, the aim of the present study was to investigate its role in cancer cell identification during surgery for gynecological malignancies. The analysis time was 5–6 min per sample. A large percentage of tumors were characterized as aneuploid, while all tumor samples had a significantly high proliferation. Flow cytometry was performed in accordance with pathological evaluation, and the method had high sensitivity and specificity. Our results verify the value of intraoperative flow cytometry in gynecological malignancies, and warrant further investigation in multicenter studies.

Abstract

Cell-cycle analysis has shown the presence of aneuploidy to be associated with poor prognosis. We developed an innovative rapid cell-cycle analysis protocol (the Ioannina protocol) that permitted the intraoperative identification of neoplastic cells in a plethora of malignancies. Herein, we aimed to investigate the potential role of cell-cycle analysis in the intraoperative characterization of gynecological malignancies. Women who underwent surgery for gynecological malignancies in our institution over a three-year period were included in this study. Permanent section pathology evaluation was used as the gold standard for malignancy evaluation. Total accordance was observed between flow cytometry and pathology evaluation. In total, 21 aneuploid cancers were detected following DNA index calculation. Of these, 20 were hyperploid and 1 was hypoploid. In addition, tumor samples were characterized by a significantly lower percentage of cells in G0/G1, as well as an induced tumor index. The response time for flow cytometry to obtain results was 5–6 min per sample. It seems that flow cytometry analyses for intraoperative tumor evaluation can be safely expanded to gynecological malignancies. This is a novel practical approach that has been proven valuable in several tumor types to date, and also seems to be reliable for gynecological malignancies. Intraoperative flow cytometry is expected to be crucial in decisions of lymph node dissection in endometrial cancers, due to its rapid response regarding the tumor invasion of part or all of the myometrial thickness. In this way, the surgeon can quickly modify the plane of dissection. Our results warrant the further investigation of applying iFC in larger, multicenter studies.

Assessing Metabolic Risk Factors for LVSI in Endometrial Cancer: A Cross-Sectional Study

Objective

This study analyzed metabolic factors associated with lymphovascular space invasion (LVSI) and compared the difference between type 1 and type 2 endometrial cancer (EC).

Methods

Four hundred patients primarily diagnosed with EC who underwent hysterectomy with pathological results at Fujian Medical University Cancer Hospital from January 2019 to January 2021 were included. Demographic variable data were collected as well as pathological results. Laboratory evaluations included fasting blood glucose (FBG), serum cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein A (Apo A) and apolipoprotein B (Apo B). Characterization of binary logistic regression models was used to test the odds ratios (ORs) between LVSI and its metabolic parameters with different subtypes of EC.

Results

The results indicated that CA125, ROMA, Ki67 score, FBG and TC were higher in EC patients with LVSI (all p<0.05). Negative ER and PR expression was positively associated with LVSI (P<0.05). CA125, ROMA, FBG, TC and ER were found to be independent risk factors for LVSI. CA125, ROMA and FBG were significantly elevated in type 1 EC patients with LVSI compared with those without LVSI (all p<0.05). TC and Ki67 scores were much higher in type 2 EC patients with vs without LVSI (all p<0.05). Negative PR expression was positively related to both type 1 and type 2 EC patients with LVSI. Consequently, CA125, ROMA, FBG and Apo B were found to be independent risk factors for LVSI in type 1 EC, and TC was found to be an independent risk factor for LVSI in type 2 EC.

Conclusion

FBG and TC were both independent risk factors for LVSI in EC. FBG and Apo B were independent risk factors for LVSI in type 1 EC. TC was an independent risk factor for LVSI in type 2 EC.

Epithelial-Mesenchymal Transition-Mediated Tumor Therapeutic Resistance

Cancer is one of the world’s most burdensome diseases, with increasing prevalence and a high mortality rate threat. Tumor recurrence and metastasis due to treatment resistance are two of the primary reasons that cancers have been so difficult to treat. The epithelial–mesenchymal transition (EMT) is essential for tumor drug resistance. EMT causes tumor cells to produce mesenchymal stem cells and quickly adapt to various injuries, showing a treatment-resistant phenotype. In addition, multiple signaling pathways and regulatory mechanisms are involved in the EMT, resulting in resistance to treatment and hard eradication of the tumors. The purpose of this study is to review the link between EMT, therapeutic resistance, and the molecular process, and to offer a theoretical framework for EMT-based tumor-sensitization therapy.

Integrated Bioinformatics Analysis of Serine Racemase as an Independent Prognostic Biomarker in Endometrial Cancer

Endometrial cancer (EC) kills about 76,000 women worldwide, with the highest incidence in industrialized countries. Because of the rise in disease mortality and new diagnoses, EC is now a top priority for women’s health. Serine racemase (SRR) is thought to play a role in the central nervous system, but its role in cancers, particularly in EC, is largely unknown. The current study starts with a pan-cancer examination of SRR’s expression and prognostic value before delving into SRR’s potential cancer-suppressing effect in patients with EC. SRR may affect the endometrial tumor immune microenvironment, according to subsequent immune-related analysis. SRR expression is also linked to several genes involved in specific pathways such as ferroptosis, N6-methyladenosine methylation, and DNA damage repair. Finally, we used the expression, correlation, and survival analyses to investigate the upstream potential regulatory non-coding RNAs of SRR. Overall, our findings highlight the prognostic significance of SRR in patients with EC, and we can formulate a reasonable hypothesis that SRR influences metabolism and obstructs key carcinogenic processes in EC.

Inhibition of BAD-Ser99 phosphorylation synergizes with PARP inhibition to ablate PTEN-deficient endometrial carcinoma

Loss of phosphatase and tensin homolog (PTEN) impairs DNA double-strand repair and confers sensitivity to poly (ADP-ribose) polymerase inhibitors (PARPis). However, PARPis also hyperactivate the MAPK and PI3K/AKT/mTOR pathways in PTEN-deficient endometrial carcinoma (EC), which allows the emergence of PARPi resistance. BCL-2-associated death promoter (BAD), integrates the common cell survival effects of the RAS/MEK/MAPK and PI3K/AKT/mTOR pathways. Herein, it was observed that increased BADSer99 (BADS99) phosphorylation in EC cells was significantly associated with PTEN-deficient status. Forced expression of phosphorylation deficient human BADS99A in PTEN-deficient EC cells significantly increased CASPASE 3/7 activity and decreased EC cell viability. Using NPB as a pharmacological inhibitor of pBADS99 phosphorylation, it was demonstrated that NPB synergized with PARPis (Olaparib, Rucaparib and Talazoparib) to enhance PARPi IC₅₀ up to 60-fold and decreased survival, foci formation, and growth in 3D ex vivo culture of PTEN-deficient EC cells. Combined NPB-PARPi treatment of PTEN-deficient EC cells stimulated apoptosis and promoted DNA damage by impairment of homologous recombination. Using the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 endonuclease system it was demonstrated that deletion of PTEN in PTEN replete EC cells enhanced the efficacy of combined NPB-PARPi treatment. Furthermore, combined inhibition of BADS99 phosphorylation and PARP ablated xenograft growth of PTEN-deficient EC cells. Similarly, a combination of NPB and PARPis significantly suppressed the growth of PTEN deficient patient-derived EC organoids. Hence, combined inhibition of BADS99 phosphorylation and PARP represents a rational and efficacious strategy to improve the prognosis of recurrent EC patients.

Elevated AKIP1 expression is associated with tumor invasion, shorter survival time and decreased chemosensitivity in endometrial carcinoma

A-kinase-interacting protein 1 (AKIP1), as a recently discovered oncoprotein, promotes cell malignant behaviors in gynecological malignancies. To the best of our knowledge, no study reports its clinical value in patients with endometrial carcinoma. The present study aimed to explore the association between AKIP1 expression and clinical features and survival in patients with endometrial carcinoma, and to assess the effect of AKIP1 knockdown on the regulation of chemosensitivity in vitro. The tumor and adjacent tissue specimens from 101 patients with endometrial carcinoma were retrieved for AKIP1 protein expression analysis using an immunohistochemistry (IHC) assay. Meanwhile, specimens from 54 patients with endometrial carcinoma were analyzed for AKIP1 mRNA expression using reverse transcription-quantitative PCR. Furthermore, an in vitro experiment was conducted in the Ishikawa cell line to determine the effect of AKIP1 modification on the chemosensitivity of cisplatin and paclitaxel. AKIP1 IHC score (P<0.001) and mRNA expression levels (P<0.001) were increased in tumor tissues compared with those in adjacent tissues. Moreover, increased AKIP1 IHC score was associated with lymphovascular invasion (P=0.007), advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.002) and shorter overall survival (OS) time (P=0.035) in the patients with endometrial carcinoma. Meanwhile, upregulated AKIP1 mRNA expression levels were associated with lymphovascular invasion (P=0.020) and advanced FIGO stage (P=0.027) in the patients with endometrial carcinoma. Multivariate Cox regression showed that tumor AKIP1 protein expression (high vs. low) independently predicted a shorter OS time (P=0.036). Silencing of AKIP1 decreased Ishikawa cell viability when treated with 5, 10, 20 and 40 µM cisplatin (all P<0.05) and decreased the half maximal inhibitory concentration value of cisplatin (P=0.003), whereas its effect on paclitaxel chemosensitivity was less obvious. Overall, elevated AKIP1 expression was associated with tumor invasion, shorter survival time and decreased chemosensitivity in endometrial carcinoma.

Sorafenib targets and inhibits the oncogenic properties of endometrial cancer stem cells via the RAF/ERK pathway

Background

Distinct subsets of cancer stem cells (CSCs) drive the initiation and progression of malignant tumors via enhanced self-renewal and development of treatment/apoptosis resistance. Endometrial CSC-selective drugs have not been successfully developed because most endometrial cell lines do not contain a sufficient proportion of stable CSCs. Here, we aimed to identify endometrial CSC-containing cell lines and to search for endometrial CSC-selective drugs.

Methods

We first assessed the presence of CSCs by identifying side populations (SPs) in several endometrial cancer cell lines. We then characterized cell viability, colony-formation, transwell invasion and xenotransplantion capability using the isolated SP cells. We also conducted real-time RT-PCR, immunoblot and immunofluorescence analyses of the cells’ expression of CSC-associated markers. Focusing on 14 putative CSC-selective drugs, we characterized their effects on the proliferation and apoptosis of endometrial cancer cell lines, examining cell viability and annexin V staining. We further examined the inhibitory effects of the selected drugs, focusing on proliferation, invasion, expression of CSC-associated markers and tumor formation.

Results

We focused on HHUA cells, an endometrial cancer cell line derived from a well-differentiated endometrial adenocarcinoma. HHUA cells contained a sufficient proportion of stable CSCs with an SP phenotype (HHUA-SP). HHUA-SP showed greater proliferation, colony-formation, and invasive capabilities compared with the main population of HHUA cells (HHUA-MP). HHUA-SP generated larger tumors with higher expression of proliferation-related markers, Ki67, c-MYC and phosphorylated ERK compared with HHUA-MP when transplanted into immunodeficient mice. Among the 14 candidate drugs, sorafenib, an inhibitor of RAF pathways and multiple kinase receptors, inhibited cell proliferation and invasion in both HHUA-SP and -MP, but more profoundly in HHUA-SP. In vivo treatment with sorafenib for 4 weeks reduced the weights of HHUA-SP-derived tumors and decreased the expression of Ki67, ZEB1, and RAF1.

Conclusions

Our results suggest that HHUA is a useful cell line for discovery and identification of endometrial CSC-selective drugs, and that sorafenib may be an effective anti-endometrial cancer drug targeting endometrial CSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02888-y.

Knockdown of the stem cell marker Musashi-1 inhibits endometrial cancer growth and sensitizes cells to radiation

Background

Endometrial carcinoma is the most common gynecological cancer in Europe. Musashi-1 is known to be a key regulator of endometrial cancer stem cells and a negative prognostic marker. In the present study, we aimed to understand growth and gene expression patterns in endometrial carcinoma after Musashi-1 knockdown in vitro and in vivo. Changes in therapeutic resistance were also assessed.

Methods

First, we performed analyses to understand Musashi-1 expression patterns using The Cancer Genome Atlas database. We then proceeded to assess effects of small interfering RNA-based Musashi-1 targeting in two endometrial carcinoma cell lines, Ishikawa and KLE. After quantifying baseline changes in cell metabolism, we used MTT tests to assess chemotherapy effects and colony formation assays to understand changes in radioresistance. For mechanistic study, we used quantitative polymerase chain reaction (qPCR) and western blotting of key Musashi-1 target genes and compared results to primary tissue database studies. Finally, xenograft experiments in a mouse model helped understand in vivo effects of Musashi-1 knockdown.

Results

Musashi-1 is aberrantly expressed in primary tumor tissues. In vitro, silencing of Musashi-1 resulted in a strong decline in cell proliferation and radioresistance, while chemoresistance remained unchanged. Loss of Musashi-1 led to downregulation of telomerase, DNA-dependent protein kinase, the Notch pathway and overexpression of cyclin-dependent kinase inhibitor p21, the latter of which we identified as a key mediator of Msi-1 knockdown-related anti-proliferative signaling. In vivo, the anti-proliferative effect was confirmed, with Msi-1 knockdown tumors being about 40% reduced in size.

Conclusions

Musashi-1 knockdown resulted in a strong decrease in endometrial cancer proliferation and a loss of radioresistance, suggesting therapeutic potential.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02891-3.

The Two-Faced Role of Autophagy in Endometrial Cancer

Autophagy, meaning “self-eating,” is a cellular catabolic process that involves lysosomal degradation of cytoplasmic materials. Autophagy contributes to both quality control and energy supply of cells, which are associated with tumorigenesis and tumor development, respectively. Endometrial cancer (EC) is the most common gynecologic cancer, and its incidence is increasing. Although autophagy plays crucial roles in several types of cancer, such as pancreatic ductal adenocarcinoma, its role in EC has not been clearly demonstrated. Activation of the PI3K/AKT/mTOR pathway, which functions to suppress autophagy, is an initial step in type 1 endometrial carcinogenesis, whereas a loss-of-function mutation of TP53, which augments autophagy via p16 induction, is the main cause of type 2 endometrial carcinogenesis. Mutations in autophagy-related genes, including ATG4C, RB1CC1/FIP200, and ULK4, have been reported in EC; thus, an aberrant autophagy mechanism may be involved in endometrial carcinogenesis. Furthermore, the biguanide diabetes drug metformin, treatment with which enhances autophagy via AMPK-mediated mTOR inactivation, has been reported to reduce the risk of EC. These findings suggest that autophagy negatively regulates endometrial carcinogenesis, and autophagy inducers may be useful for chemoprevention of EC. In contrast, autophagy appears to promote EC once it is established. Consistent with this, treatment with chloroquine, an autophagy inhibitor, is reported to attenuate EC cell proliferation. Moreover, chemotherapy-induced autophagy triggers chemoresistance in EC cells. As autophagy has a tumor-promoting function, the combination of chemotherapy and autophagy inhibitors such as chloroquine could be a potent therapeutic option for patients with EC. In conclusion, autophagy plays a dual role in the prevention and treatment of EC. Therefore, targeting autophagy to prevent and treat EC requires diametrically opposed strategies.

Differential Expression of Steroid Hormone Receptors and Ten Eleven Translocation Proteins in Endometrial Cancer Cells

Steroid hormones govern the complex, cyclic changes of the endometrium, predominantly through their receptors. An interplay between steroid hormones and epigenetic mechanisms controls the dynamic endometrial gene regulation. Abnormalities in expression of genes and enzymes associated with steroid hormone signaling, contribute to a disturbed hormonal equilibrium. Limited evidence suggests the involvement of TET (Ten Eleven Translocation)-mediated DNA hydroxymethylation in endometrial cancer, with some data on the use of TET1 as a potential prognostic and diagnostic biomarker, however the mechanisms guiding it and its regulation remains unexplored. This study aims to explore the changes in the expressions of TETs and steroid hormone receptors in response to estrogen and progesterone in endometrial cancer cells. Gene expression was examined using real-time PCR and protein expression was quantified using fluorescent western blotting in endometrial cancer cell lines (AN3 and RL95-2). Results indicate that TET1 and TET3 gene and protein expression was cell-specific in cancer cell-lines. Protein expression of TET1 was downregulated in AN3 cells, while TET1 and TET3 expressions were both upregulated in RL95-2 cells in response to estrogen-progesterone. Further, a decreased AR expression in AN3 cells and an increased ERα and ERβ protein expressions in RL95-2 cells was seen in response to estrogen-progesterone. PR gene and protein expression was absent from both cancer cell-lines. Overall, results imply that expressions of steroid hormones, steroid-hormone receptors and TETs are co-regulated in endometrial cancer-cells. Further studies are needed to interpret how these mechanisms fit in with DNMTs and DNA methylation in regulating endometrial biology. Understanding the role of TETs and hydroxymethylation in steroid hormone receptor regulation is crucial to comprehend how these mechanisms work together in a broader context of epigenetics in the endometrium and its pathologies.

UPF1 contributes to the maintenance of endometrial cancer stem cell phenotype by stabilizing LINC00963

Endometrial cancer stem cells (ECSCs) play a vital role in endometrial cancer (EC) metastasis, relapse, and chemoresistance. However, the molecular mechanisms that sustain ECSCs remain elusive. Here, we showed that the expression of UPF1 was upregulated in EC tissues and ECSCs and correlated with poor clinicopathological characteristics. UPF1 silencing suppressed ECSC hallmarks, such as sphere formation ability, carboplatin resistance, migration and invasion, and cell cycle progression. UPF1 regulated the behavior and fate of ECSCs by stabilizing LINC00963. LINC00963 further shares the same miRNA response element with the core transcription factor SOX2 and relieved the suppression of SOX2 by miR-508-5p in self-renewing ECSCs. Notably, inhibition of UPF1 and LINC00963 in combination severely impaired the in vivo tumorigenic potential of ECSCs. We demonstrate that the UPF1/LINC00963/miR-508-5p/SOX2 axis has potential value in modulating ECSC maintenance, chemoresistance, and tumorigenesis in EC, which highlights a novel promising target for EC treatment.

Bone Marrow-Derived Cells in Endometrial Cancer Pathogenesis: Insights from Breast Cancer

Endometrial cancer is the most common gynecological cancer, representing 3.5% of all new cancer cases in the United States. Abnormal stem cell-like cells, referred to as cancer stem cells (CSCs), reside in the endometrium and possess the capacity to self-renew and differentiate into cancer progenitors, leading to tumor progression. Herein we review the role of the endometrial microenvironment and sex hormone signaling in sustaining EC progenitors and potentially promoting dormancy, a cellular state characterized by cell cycle quiescence and resistance to conventional treatments. We offer perspective on mechanisms by which bone marrow-derived cells (BMDCs) within the endometrial microenvironment could promote endometrial CSC (eCSC) survival and/or dormancy. Our perspective relies on the well-established example of another sex hormone-driven cancer, breast cancer, in which the BM microenvironment plays a crucial role in acquisition of CSC phenotype and dormancy. Our previous studies demonstrate that BMDCs migrate to the endometrium and express sex hormone (estrogen and progesterone) receptors. Whether the BM is a source of eCSCs is unknown; alternatively, crosstalk between BMDCs and CSCs within the endometrial microenvironment could be an additional mechanism supporting eCSCs and tumorigenesis. Elucidating these mechanisms will provide avenues to develop novel therapeutic interventions for EC.

Evaluation of immunohistochemical expression of stem cell markers (NANOG and CD133) in normal, hyperplastic, and malignant endometrium

Cancer stem cells (CSC) are a potential cause for recurrence, metastasis, and resistance of tumors to different therapeutic modalities like hormonal radiotherapy and chemotherapy. We investigated two CSC markers (NANOG and CD 133) in normal, hyperplastic endometrium and endometrial carcinoma. A total of 93 formalin-fixed paraffin-embedded tissue blocks were used for immunohistochemical expression of NANOG and CD133 markers. NANOG expression was detected in 88.37% of endometrial carcinoma cases compared to 15% of the normal proliferative endometrium and 60% of hyperplasia cases. In endometrial carcinoma, high NANOG expression was significantly correlated with high grade, deep myometrial invasion, lymph node metastasis, and high stage with p-values (0.009, 0.005, 0.014, and 0.003, respectively). CD133 was positive in 76.74% of endometrial carcinoma cases, and it showed a significant correlation with deep myometrial invasion, positive lymph node, positive lymphovascular invasion, and high stage (p-values 0.003, 0.001, 0.003, and 0.013, respectively). Normal endometrium showed less expression of CD133 (only 5%) than hyperplasia and endometrial carcinoma with a statistically highly significant difference (p less than 0.0001). Hyperplastic cases with atypia expressed higher CD133 than those without atypia (6 out of 12 versus 3 out of 18). However, this difference was not statistically significant (p-value 0.111). The cancer stem cell markers NANOG and CD 133 are expressed in a high percentage in endometrial carcinoma compared to normal and hyperplasia and their expression is positively correlated with the aggressive behavior of the tumor. High expression of these two markers in apparently normal tissue around the tumor and in hyperplastic conditions with atypia suggests the possibility to use NANOG and CD133 expression as a diagnostic marker distinguishing dysplasia from reactive atypia. Therefore, inhibition of these markers can be a promising method to stop the progression of early cancers.

Progesterone Receptor Membrane Component (PGRMC)1 and PGRMC2 and Their Roles in Ovarian and Endometrial Cancer

Cancers of the female reproductive tract are both lethal and highly prevalent. For example, the five-year survival rate of women diagnosed with ovarian cancer is still less than 50%, and endometrial cancer is the fourth most common cancer in women with > 65,000 new cases in the United States in 2020. Among the many genes already established as key participants in ovarian and endometrial oncogenesis, progesterone receptor membrane component (PGRMC)1 and PGRMC2 have gained recent attention given that there is now solid correlative information supporting a role for at least PGRMC1 in enhancing tumor growth and chemoresistance. The expression of PGRMC1 is significantly increased in both ovarian and endometrial cancers, similar to that reported in other cancer types. Xenograft studies using human ovarian and endometrial cancer cell lines in immunocompromised mice demonstrate that reduced expression of PGRMC1 results in tumors that grow substantially slower. While the molecular underpinnings of PGRMCs' mechanisms of action are not clearly established, it is known that PGRMCs regulate survival pathways that attenuate stress-induced cell death. The objective of this review is to provide an overview of what is known about the roles that PGRMC1 and PGRMC2 play in ovarian and endometrial cancers, particularly as related to the mechanisms through which they regulate mitosis, apoptosis, chemoresistance, and cell migration.

Prognostic and clinicopathological significance of TMEFF2, SMOC-2, and SOX17 expression in endometrial carcinoma

Background there is a need for novel biomarkers and targeting therapies for predicting Endometrial carcinoma (EC) progression and recurrence. TMEFF2 is a gene that was found to play a role in EMT. SMOC-2 is expressed in embryogenesis and it was identified as a recent stem cell-related gene that has a role in cancer progression. SRY-box 17 (SOX17) is a member of the SRY-related HMG-box (SOX) family of transcription factors. Dysregulation or downregulation of SOX17 expression was found in many cancer tissues.

AIM

In the present study, we aimed to assess the tissue protein expressions of TMEFF2, SMOC-2, and SOX17 in EC using immunohistochemistry to evaluate their clinicopathological values and prognostic roles in EC patients.

PATIENTS AND METHODS

This is prospective cohort study included 120 patients with EC. Sections from 120 paraffin blocks were retrieved and stained with TMEFF2, SMOC-2, and SOX17 using immunohistochemistry, the expression of markers in all tissue samples was assessed, analyzed and correlation of pathological parameters with the levels of expression was done. All patients were followed up till death or till the last known alive data for about 50 months (range from 25 to 60).

RESULTS

TMEFF2, SMOC-2 expression was correlated with the presence of lymph node metastases (p = 0.023), distant metastasis (p = 0.039) recurrence of the tumor after successful therapy, overall survival, and disease-free survival (p < 0.001). SOX17 positive expression was positively correlated with low grade (p = 0.019), absence of lymph node metastasis (p = 0.001), absence of distant metastasis (p = 0.013), low stage (p = 0.03), and its negative expression was positively correlated with recurrence of the tumor after successful therapy, overall survival and disease-free survival (p = 0.001). In conclusion, we demonstrated that both TMEFF2 and SMOC-2 were highly expressed in EC and were associated with a shortened survival rate, dismal outcome, and poor prognosis in EC patients. While SOX17 expression was related to a favorable outcome and its down-regulation was associated with dismal EC patient's survival.

CD133 Expression in the Nucleus Is Associated with Endometrial Carcinoma Staging and Tumor Angioinvasion

BACKGROUND

(1) Endometrial cancer is one of the most common cancers affecting women, with a growing incidence. To better understand the different behaviors associated with endometrial cancer, it is necessary to understand the changes that occur at a molecular level. CD133 is one of the factors that regulate tumor progression, which is primarily known as the transmembrane glycoprotein associated with tumor progression or cancer stem cells. The aim of our study was to assess the impact of subcellular CD133 expression on the clinical course of endometrial cancer. (2) Methods: CD133 expression in the plasma membrane, nucleus, and cytoplasm was assessed by immunohistochemical staining in a group of 64 patients with endometrial cancer representing FIGO I-IV stages, grades 1-3 and accounting for tumor angioinvasion. (3) Results: Nuclear localization of CD133 expression was increased in FIGO IB-IV stages compared to FIGO IA. Furthermore, CD133 expression in the nucleus and plasma membrane is positively and negatively associated with a higher grade of endometrial cancer and angioinvasion, respectively. (4) Conclusions: Our findings suggest that positive nuclear CD133 expression in the tumor may be related to a less favorable prognosis of endometrial carcinoma patients and has emerged as a useful biomarker of a high-risk group.

The Elusive Endometrial Epithelial Stem/Progenitor Cells

The human endometrium undergoes approximately 450 cycles of proliferation, differentiation, shedding and regeneration over a woman's reproductive lifetime. The regenerative capacity of the endometrium is attributed to stem/progenitor cells residing in the basalis layer of the tissue. Mesenchymal stem cells have been extensively studied in the endometrium, whereas endometrial epithelial stem/progenitor cells have remained more elusive. This review details the discovery of human and mouse endometrial epithelial stem/progenitor cells. It highlights recent significant developments identifying putative markers of these epithelial stem/progenitor cells that reveal their in vivo identity, location in both human and mouse endometrium, raising common but also different viewpoints. The review also outlines the techniques used to identify epithelial stem/progenitor cells, specifically in vitro functional assays and in vivo lineage tracing. We will also discuss their known interactions and hierarchy and known roles in endometrial dynamics across the menstrual or estrous cycle including re-epithelialization at menses and regeneration of the tissue during the proliferative phase. We also detail their potential role in endometrial proliferative disorders such as endometriosis.

Suppressing CHD1L reduces the proliferation and chemoresistance in osteosarcoma

Osteosarcoma (OS) is the most common bone malignant tumor. However, the genetic basis of OS pathogenesis is still not understood, and occurrence of chemo-resistance is a major reason for the high morbidity of OS patients. Recently, chromodomain helicase/ATPase DNA binding protein 1-like gene (CHD1L) has been identified as a gene related to malignant tumor progression. Unfortunately, its effects on OS development and drug resistance are still not understood. In the study, we attempted to investigate the effects of CHD1L on tumorigenesis and chemoresistance in OS. We found that CHD1L expression was markedly up-regulated in OS samples, especially in cisplatin (cDDP)-resistant patients. We also showed that OS cells with CHD1L knockdown were more sensitive to cDDP treatment with lower IC₅₀ values. In addition, we found that CHD1L deletion markedly reduced cell proliferation and induced apoptosis in OS cells with cDDP resistance. Moreover, the properties of cancer stem cells were highly suppressed in cDDP-resistant OS cells following CHD1L knockdown. Furthermore, multidrug resistance protein 1 (MDR-1) expression levels were dramatically decreased in OS cells with cDDP resistance when CHD1L was suppressed. Functional analysis indicated that CHD1L knockdown clearly restrained the activation of ERK1/2, protein kinase B (AKT) and NF-κB signaling pathways in cDDP-resistant OS cells. Consistently, animal experiments suggested that CHD1L suppression mitigated cDDP resistance in the generated in vivo xenografts. Collectively, CHD1L could modulate chemoresistance of OS cells to cDDP, and thus may be inspiring findings for overcoming drug resistance in OS.

Comprehensive Analysis of the Control of Cancer Stem Cell Characteristics in Endometrial Cancer by Network Analysis

Background

Cancer stem cells play an important role in endometrial cancer (EC). It is closely related to self-renewal and therapeutic resistance of EC.

Methods

In this study, WGCNA (weighted gene coexpression network analysis) was used to analyze the relationship between genes and clinical features. We also performed immune cell infiltration analysis of a key module by using ImmuCellAI (Immune Cell Abundance Identifier). Then, key genes were verified in the GEO database. Finally, causal relationship analysis and protein-protein interaction analysis were performed in DisNor tool and STRING.

Result

The mRNA expression-based stemness index (mRNAsi) is significantly lower in normal tissues and is significantly higher in individuals with stage IV or high-grade cancer and those who are obese or postmenopausal. Nineteen key genes (ORC6, C1orf112, RAD54L, SGO2, BUB1, PLK4, KIF18B, BUB1B, TTK, NCAPG, XRCC2, CENPF, KIF15, RACGAP1, ARHGAP11A, TPX2, KIF14, KIF4A, and NCAPH) that were enriched mainly in terms related to the cell cycle and DNA replication were selected by weighted gene coexpression network analysis (WGCNA). Based on the key modules, the numbers of NKT cells, NK cells, and neutrophils in the normal group were significantly higher than those in the cancer group. PLK1, CDK1, and MAD2L1, which were correlated with upstream genes, may be an regulated upstream of key genes.

Conclusion

PLK1, CDK1, and MAD2L1 which were strongly correlated with upstream genes may be a regulated upstream of key genes.

Stem Cells and the Endometrium: From the Discovery of Adult Stem Cells to Pre-Clinical Models

Adult stem cells (ASCs) were long suspected to exist in the endometrium. Indeed, several types of endometrial ASCs were identified in rodents and humans through diverse isolation and characterization techniques. Putative stromal and epithelial stem cell niches were identified in murine models using label-retention techniques. In humans, functional methods (clonogenicity, long-term culture, and multi-lineage differentiation assays) and stem cell markers (CD146, SUSD2/W5C5, LGR5, NTPDase2, SSEA-1, or N-cadherin) facilitated the identification of three main types of endogenous endometrial ASCs: stromal, epithelial progenitor, and endothelial stem cells. Further, exogenous populations of stem cells derived from bone marrow may act as key effectors of the endometrial ASC niche. These findings are promoting the development of stem cell therapies for endometrial pathologies, with an evolution towards paracrine approaches. At the same time, promising therapeutic alternatives based on bioengineering have been proposed.

Targeting the Sonic Hedgehog Pathway to Suppress the Expression of the Cancer Stem Cell (CSC)-Related Transcription Factors and CSC-Driven Thyroid Tumor Growth

Simple Summary

Poorly differentiated and anaplastic thyroid cancers respond poorly to surgery, radiation, and hormone therapy. Cancer stem cells play an important role in tumor growth, drug resistance, and recurrence. This study focuses on how the sonic hedgehog (Shh) pathway maintains thyroid cancer stem cell self-renewal and whether it can be targeted for anticancer therapy. The authors report that the Shh pathway regulates the expression of BMI1 and SOX2, two genes involved in stem cell self-renewal, and that targeting the Shh pathway has little effect on thyroid tumor xenografts but can inhibit the growth of tumor xenografts derived from thyroid cancer stem cells. This study advances the knowledge on how thyroid cancer stem cells regenerate and highlights the potential therapeutic values of targeting the Shh pathway.

Abstract

The sonic hedgehog (Shh) pathway plays important roles in tumorigenesis, tumor growth, drug resistance, and metastasis. We and others have reported earlier that this pathway is highly activated in thyroid cancer. However, its role in thyroid cancer stem cell (CSC) self-renewal and tumor development remains incompletely understood. B lymphoma Mo-MLV insertion region 1 homolog (BMI1) and SRY-Box Transcription Factor 2 (SOX2) are two CSC-related transcription factors that have been implicated in promoting CSC self-renewal. The objective of our current investigation was to determine the role of the Shh pathway in regulating BMI1 and SOX2 expression in thyroid cancer and promoting thyroid tumor growth and development. Here we report that inhibition of the Shh pathway by Gli1 siRNA or by cyclopamine and GANT61 reduced BMI1 and SOX2 expression in SW1736 and KAT-18 cells, two anaplastic thyroid cancer cell lines. The opposite results were obtained in cells overexpressing Gli1 or its downstream transcription factor Snail. The Shh pathway regulated SOX2 and BMI1 expression at a transcriptional and post-transcriptional level, respectively. GANT61 treatment suppressed the growth of SW1736 CSC-derived tumor xenografts but did not significantly inhibit the growth of tumors grown from bulk tumor cells. Clinicopathological analyses of thyroid tumor specimens by immunohistochemical (IHC) staining revealed that BMI1 and SOX2 were highly expressed in thyroid cancer and correlated with Gli1 expression. Our study provides evidence that activation of the Shh pathway leads to increased BMI1 and SOX2 expression in thyroid cancer and promotes thyroid CSC-driven tumor initiation. Targeting the Shh pathway may have therapeutic value for treating thyroid cancer and preventing recurrence.

Polychlorinated biphenyl quinone induced the acquisition of cancer stem cells properties and epithelial-mesenchymal transition through Wnt/β-catenin

Polychlorinated biphenyls (PCBs) are persistent industrial pollutants that have been linked to breast cancer progression. However, their molecular mechanism(s) are currently unclear. Our previous assessment suggested that the highly reactive PCB metabolite 2,3,5-trichloro-6-phenyl-[1,4]-benzoquinone (PCB29-pQ) induces the metastasis of breast cancer. Here, our data illustrate that PCB29-pQ increases cancer stem cell (CSC) marker expression, resulting in an increase in the epithelial-mesenchymal transition (EMT) in MDA-MB-231 breast cancer cells; further, the Wnt/β-catenin pathway also becomes activated by PCB29-pQ. When the Wnt/β-catenin pathway is inhibited, the promotion of CSC properties and EMT by PCB29-pQ were accordingly reversed. In addition, the overproduction of reactive oxygen species (ROS) mediated by PCB29-pQ plays a key role in Wnt/β-catenin activation. Collectively, our current data designated the regulatory role of Wnt/β-catenin in PCB29-pQ-triggered acquisition of CSC properties and EMT.

Notch and Endometrial Cancer

The human endometrium is a unique, highly dynamic tissue that undergoes cyclic changes of cell proliferation, differentiation, and death. Endometrial cancer is the most common malignancy among women in developed countries. Importantly, the incidence of endometrial cancer is rising in high-income countries. Currently histological classification is used for subtyping of endometrial cancer, while ongoing research is evaluating markers for more accurate molecular classification. Evolutionary conserved Notch signaling pathway regulates diverse cellular processes such as proliferation, differentiation, and cell invasion. Accumulating evidence links aberrant Notch signaling with diseases such as hyperplasia and endometrial cancer. This chapter summarizes the current state of Notch signaling investigations in the endometrium, endometriosis, and endometrial cancer.

Tribbles Pseudokinase 3 Contributes to Cancer Stemness of Endometrial Cancer Cells by Regulating β-Catenin Expression

Simple Summary

Endometrial cancer (EC) is the second most common female malignancy worldwide, but the pathogenesis is not fully understood. Tribbles pseudokinase 3 (TRIB3) is a kind of scaffold protein that may regulate multiple cellular processes by organizing binding partner proteins involving signaling transduction pathways. The goal of this study is to investigate if TRIB3 is involved in the malignant features of EC. Our data demonstrate that TRIB3 positively regulates the cancer stem-cell activity and in vivo tumorigenicity of EC cells by modulating β-catenin signaling through directly interacting with the ELF4 transcription factor. Our results could lead to new insight for developing a novel therapeutic strategy for EC by targeting TRIB3.

Abstract

Endometrial cancer (EC) is the second most common gynecological malignancy worldwide. Tribbles pseudokinase 3 (TRIB3) is a scaffolding protein that regulates intracellular signal transduction, and its role in tumor development is controversial. Here, we investigated the biological function of TRIB3 in EC. We found that the messenger RNA (mRNA) expression level of TRIB3 was significantly and positively correlated with shorter overall survival of EC patients in The Cancer Genome Atlas database. The protein expression of TRIB3 was found to be significantly increased in EC cancer stem cells (CSCs) enriched by tumorsphere cultivation. Knockdown of TRIB3 in EC cells suppressed tumorsphere formation, the expression of cancer stemness genes, and the in vivo tumorigenesis. The expression of β-catenin at both the protein and the mRNA levels was downregulated upon TRIB3 silencing. TRIB3 was found to interact with E74 Like ETS transcription factor 4 (ELF4) in the nucleus and bound to ELF4 consensus sites within the catenin beta 1 (CTNNB1) promoter in EC cell lines. These data indicated that TRIB3 may regulate CTNNB1 transcription by enhancing the recruitment of ELF4 to the CTNNB1 promoter. In conclusion, our results suggest that TRIB3 plays an oncogenic role in EC and positively regulates the self-renewal and tumorigenicity of EC-CSCs. Targeting TRIB3 is considered as a potential therapeutic strategy in future EC therapy.

miR‑34c‑5p targets Notch1 and suppresses the metastasis and invasion of cervical cancer

Micro (mi)RNAs are crucial participants in the progression of cervical cancer (CC). Growing evidence indicates that miRNA (miR)-34c-5p is a pivotal tumor suppressor in numerous types of cancer and its functions in CC require further investigating. The present study demonstrated that there was a decreased level of miR-34c-5p in CC-associated cell lines compared with healthy control samples. It also demonstrated that miR-34c-5p targeted Notch1 and suppressed CC progression. Dual-Luciferase reporter assays verified the targeted relationship of miR-34c-5p and Notch1. The expression of Notch1 in HeLa cells was markedly reduced following miR-34c-5p overexpression and the proliferation, migration and invasion of HeLa cells were reduced although apoptosis was accelerated. However, overexpression of miR-34c-5p was reversed following the addition of Notch1, which supported the finding of the targeted relationship between miR-34c-5p and Notch1. Flow cytometry demonstrated that miR-34c-5p inhibited the proliferation of HeLa cells while accelerating apoptosis. The present study concluded that miR-34c-5p was a tumor suppressor in CC and may be a novel measure for the future treatment of CC.

Report of the National Cancer Institute and the Eunice Kennedy Shriver National Institute of Child Health and Human Development-sponsored workshop: gynecology and women's health-benign conditions and cancer

The Division of Cancer Prevention and the Division of Cancer Biology at the National Cancer Institute and the Gynecologic Health and Disease Branch in the National Institute of Child Health and Human Development organized a workshop in April 2019 to explore current insights into the progression of gynecologic cancers from benign conditions. Working groups were formed based on 3 gynecologic disease types: (1) Endometriosis or Endometrial Cancer and Endometrial-Associated Ovarian Cancer, (2) Uterine Fibroids (Leiomyoma) or Leiomyosarcoma, and (3) Adenomyosis or Adenocarcinoma. In this report, we highlight the key questions and current challenges that emerged from the working group discussions and present potential research opportunities that may advance our understanding of the progression of gynecologic benign conditions to cancer.

Endometrial cancer-is our knowledge changing?

In developed countries, endometrial cancer (EC) is the most frequent gynecologic malignancy in postmenopausal women. At the same time, EC has become one of the most common cancers in numerous developing countries, probably influenced by global epidemic of obesity. The majority of patients have low-grade endometrioid cancer with a high 5-year survival rate, but with high-risk EC, the survival rates are still rather low. However, despite intensive research in last decades, our knowledge of the mechanisms, risk factors, diagnosis and treatment have not significantly improved. The standard treatment of all types of EC is still a traditional combination of surgery, irradiation and/or chemotherapy, despite the fact that each of these options is not without having some negative side effects. Despite the fact that on the molecular level, EC is relatively well-studied, but the efforts to transform these findings into either diagnosis or therapies of EC remain elusive. In addition, some research into risk factors involved in the development or progression of EC seems to be more a fishing expedition than a well thought-out approach. The purpose of this review is to summarize the most recent developments in the search for biomarkers and prognostic markers and to discuss the progress in EC treatment.

Hypoxia induces an endometrial cancer stem-like cell phenotype via HIF-dependent demethylation of SOX2 mRNA

Endometrial cancer stem cells (ECSCs) are stem-like cells endowed with self-renewal and differentiation abilities, and these cells are essential for cancer progression in endometrial cancer (EC). As hallmarks of the tumour microenvironment (TME), hypoxia and hypoxia-inducing factors (HIFs) give rise to the dysregulation of tumour stemness genes, such as SOX2. Against this backdrop, we investigated the regulatory mechanisms regulated by HIFs and SOX2 in ECSCs during EC development. Here, ECSCs isolated from EC cell lines and tissues were found to express stemness genes (CD133 and aldehyde dehydrogenase, ALDH1) following the induction of their ECSC expansion. Notably, m⁶A methylation of RNA and HIF-1α/2α-dependent AlkB homologue 5 (ALKBH5) participate in the regulation of HIFs and SOX2 in EC, as confirmed by the observations that mRNA levels of m⁶A demethylases and ALKBH5 significantly increase under hypoxic conditions in ECSCs. Moreover, hypoxia and high ALKBH5 levels restore the stem-like state of differentiated ECSCs and increase the ECSC-like phenotype, whereas the knockdown of HIFs or ALKBH5 significantly reduces their tumour initiation capacity. In addition, our findings validate the role of ALKBH5 in promoting SOX2 transcription via mRNA demethylation, thereby maintaining the stem-like state and tumorigenicity potential of ECSCs. In conclusion, these observations demonstrate a critical role for m⁶A methylation-mediated regulation of the HIF-ALKBH5-SOX2 axis during ECSC expansion in hypoxic TMEs.

Using mRNAsi to identify prognostic-related genes in endometrial carcinoma based on WGCNA

AIMS

Cancer Stem Cells (CSCs) refers to heterogeneous tumor cells retaining the abilities of self-renewal and differentiation. This study used mRNAsi, which is an index to describe the similarity between tumor cells and CSCs, to define genes involved in endometrial carcinoma.

MATERIALS AND METHODS

The mRNA expression profiles of 552 tumor samples and 23 non-tumor samples were calculated for differentially expressed genes. WGCNA was utilized to construct gene co-expression networks and classify screened genes into different modules. Univariate and multivariate Cox regression models were performed to identify and construct the prognostic model. Time-dependent receiver operating characteristic (ROC), Kaplan-Meier curve, multivariate Cox regression analysis, and nomogram were used to assess the prognostic capacity of the six-gene signature. The screened genes were further validated by GEO (GSE17025) and qRT-PCR in EC tissues.

KEY FINDINGS

2573 upregulated and 1890 downregulated genes were identified. A total of 35 genes in the turquoise module were identified as key genes. With multivariate analysis, six genes (DEPDC1, FAM83D, NCAPH, SPC25, TPX2, and TTK) up-regulated in endometrial carcinoma were identified, and their higher expression was associated with a higher stage/age/grade. Moreover, ROC and Kaplan-Meier plots indicated these genes had a high prognostic value for EC. A nomogram was constructed for clinical use. In addition, we explored the pathogenesis involving six genes. The results showed that these genes may become pathogenic as their copy numbers changes and methylation level reduces. Finally, GSEA revealed these genes had a close association with cell cycle, etc. SIGNIFICANCE: These findings may provide new insights into the treatment of diseases.

Metabolomic Biomarkers for Detection, Prognosis and Identifying Recurrence in Endometrial Cancer

Metabolic reprogramming is increasingly recognised as one of the defining hallmarks of tumorigenesis. There is compelling evidence to suggest that endometrial cancer develops and progresses in the context of profound metabolic dysfunction. Whilst the incidence of endometrial cancer continues to rise in parallel with the global epidemic of obesity, there are, as yet, no validated biomarkers that can aid risk prediction, early detection, prognostic evaluation or surveillance. Advances in high-throughput technologies have, in recent times, shown promise for biomarker discovery based on genomic, transcriptomic, proteomic and metabolomic platforms. Metabolomics, the large-scale study of metabolites, deals with the downstream products of the other omics technologies and thus best reflects the human phenotype. This review aims to provide a summary and critical synthesis of the existing literature with the ultimate goal of identifying the most promising metabolite biomarkers that can augment current endometrial cancer diagnostic, prognostic and recurrence surveillance strategies. Identified metabolites and their biochemical pathways are discussed in the context of what we know about endometrial carcinogenesis and their potential clinical utility is evaluated. Finally, we underscore the challenges inherent in metabolomic biomarker discovery and validation and provide fresh perspectives and directions for future endometrial cancer biomarker research.

The Interplay of Tumor Stroma and Translational Factors in Endometrial Cancer

Endometrial cancer (EC) is a common gynecologic malignancy which continues to have a poor prognosis in advanced stages due to current therapeutic limitations. A significant mechanism of chemoresistance in EC has been shown to also be the enhancement of epithelial to mesenchymal transition (EMT) and the subsequent obtainment of stem cell-like characteristics of EC. Current evidence on EMT in EC however fails to explain the relationship leading to an EMT signaling enhancement. Our review therefore focuses on understanding eukaryotic translation initiation factors (eIFs) as key regulators of the translational process in enhancing EMT and subsequently impacting higher chemoresistance of EC. We identified pathways connected to the development of a microenvironment for EMT, inducers of the process specifically related to estrogen receptors as well as their interplay with eIFs. In the future, investigation elucidating the translational biology of EC in EMT may therefore focus on the signaling between protein kinase RNA-like ER kinase (PERK) and eIF2alpha as well as eIF3B.

Determinants of Sensitivity to Radiotherapy in Endometrial Cancer

Radiotherapy is one of the cornerstone treatments for endometrial cancer and has successfully diminished the risk of local recurrences after surgery. However, a considerable percentage of patients suffers tumor relapse due to radioresistance mechanisms. Knowledge about the molecular determinants that confer radioresistance or radiosensitivity in endometrial cancer is still partial, as opposed to other cancers. In this review, we have highlighted different central cellular signaling pathways and processes that are known to modulate response to radiotherapy in endometrial cancer such as PI3K/AKT, MAPK and NF-κB pathways, growth factor receptor signaling, DNA damage repair mechanisms and the immune system. Moreover, we have listed different clinical trials employing targeted therapies against some of the aforementioned signaling pathways and members with radiotherapy. Finally, we have identified the latest advances in radiotherapy that have started being utilized in endometrial cancer, which include modern radiotherapy and radiogenomics. New molecular and genetic studies in association with the analysis of radiation responses in endometrial cancer will assist clinicians in taking suitable decisions for each individual patient and pave the path for personalized radiotherapy.