Cells with characteristics of cancer stem/progenitor cells express the CD133 antigen in human endometrial tumors

MAPK14 /p38α Shapes the Molecular Landscape of Endometrial Cancer and promotes Tumorigenic Characteristics

The molecular underpinnings of H igh G rade E ndometrial C arcinoma (HGEC) metastatic growth and survival are poorly understood. Here we show that ascites-derived and primary tumor HGEC cell lines in 3D spheroid culture faithfully recapitulate key features of malignant peritoneal effusion and exhibit fundamentally distinct transcriptomic, proteomic and metabolomic landscapes when compared with conventional 2D monolayers. Using genetic screening platform we identify MAPK14 (which encodes the protein kinase p38α) as a specific requirement for HGEC in spheroid culture. MAPK14 /p38α has broad roles in programing the phosphoproteome, transcriptome and metabolome of HGEC spheroids, yet has negligible impact on monolayer cultures. MAPK14 promotes tumorigenicity in vivo and is specifically required to sustain a sub-population of spheroid cells that is enriched in cancer stemness markers. Therefore, spheroid growth of HGEC activates unique biological programs, including p38α signaling, that cannot be captured using 2D culture models and are highly relevant to malignant disease pathology.

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.

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.

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.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

The roles and clinical applications of interleukins in endometrial carcinoma

As a common malignant tumor of the female reproductive system, endometrial carcinoma (EC) seriously endangers women's health with an increasing incidence. The oncogenesis and progression of cancer are closely linked with immune microenvironment, of which interleukins are the important components. In order to illustrate the roles and clinical applications of interleukins in EC, literature of interleukins and EC were reviewed. Based on the present studies, interleukins play crucial roles in the oncogenesis and development of EC via regulating the proliferation, migration, invasion, angiogenesis, apoptosis, pyroptosis and autophagy of EC as well as the immune function against EC. And some of the interleukins seems to have prospective clinical applications in EC, such as evaluating the risk of tumorigenesis, discriminating the malignancy from benign disorders or normal condition, indicating cancer aggressiveness, predicting the prognosis of patients and serving as the novel therapy. However, there is still a long way to go before the clinical applications of interleukins in EC come into reality. Nevertheless, it is certain that the exploration of interleukins will definitely be of great benefit to the screening, diagnosis and treatment of EC in the future.

Regulation of the aryl hydrocarbon receptor in cancer and cancer stem cells of gynecological malignancies: An update on signaling pathways

Gynecological malignancies are a female type of cancers that affects the reproductive system. Cancer metastasis or recurrence mediated by cellular invasiveness occurs at advanced stages of cancer progression. Cancer Stem Cells (CSCs) enrichment in tumors leads to chemoresistance, which results in cancer mortality. Exposure to environmental pollutants such as polycyclic aromatic hydrocarbons is associated with an increased the risk of CSC enrichment in gynecological cancers. One of the important pathways that mediates the metabolism and bioactivation of these environmental chemicals is the transcription factor, aryl hydrocarbon receptor (AhR). The present review explores the molecular mechanisms regulating the crosstalk and interaction of the AhR with cancer-related signaling pathways, such as apoptosis, epithelial-mesenchymal transition, immune checkpoints, and G-protein-coupled receptors in several gynecological malignancies such as ovarian, uterine, endometrial, and cervical cancers. The review also discusses the potential of targeting the AhR pathway as a novel chemotherapy for gynecological cancers.

Molecular Insights into Endometrial Cancer in Mice

Pluripotent, very small embryonic-like stem cells (VSELs) and the 'progenitors' endometrial stem cells (EnSCs) along with associated molecular changes in endometrial cancer, that developed seven months after neonatal exposure to estradiol in one of the sixty mice, were studied in the present study. Endocrine disruption affected both endometrium and myometrium, there was accumulation of endometrial fluid and significant hyperplasia. Disrupted endometrial-myometrial junction resulted in mobilization of myometrial cells into endometrium and epithelial and stromal cells into myometrium suggestive of adenomyosis. Markers specific for VSELs/ EnSCs (OCT-4, NANOG, SSEA-1, SCA-1, c-KIT) showed increased expression in uterine sections and marked upregulation of corresponding transcripts (Oct-4A, Oct-4, Sox-2, Nanog, Sca-1, c-Kit) was noted in RNA extracted from both uterine tissue and stem cells enriched from endometrial fluid. Hormonal receptors (ER-α, ER-β, PR, FSHR) were upregulated in both tumor sections and in endometrial fluid. ER-β and FSHR (Fshr3) expression was prominent suggesting a major role in endometrial cancer. Cancer cells showed global hypomethylation (reduced expression of 5-methyl cytosine), reduced expression of tumor suppressor gene (PTEN) and increased expression of cancer stem cells marker (CD166) which suggested dysregulation and aberrant oncogenic events. Increased expression of PCNA, Ki67, SOX-9 suggested excessive proliferation and hyperplasia which are predominant signs of endometrial cancer. Results suggest that VSELs increase in numbers and possibly transform into cancer stem cells (co-express CD166 and OCT-4) in endometrial cancer. Expression of OCT-4, CD133, ALDHA1 and CD166 in side-population cells from human endometrial cancer samples suggests a possible role of VSELs in human endometrial cancer as well.

Endometrial Cancer Stem Cells: Where Do We Stand and Where Should We Go?

Endometrial cancer is one of the most common malignant diseases in women worldwide, with an incidence of 5.9%. Thus, it is the most frequent cancer of the female genital tract, with more than 34,000 women dying, in Europe and North America alone. Endometrial Cancer Stem Cells (CSC) might be drivers of carcinogenesis as well as metastatic and recurrent disease. Therefore, targeting CSCs is of high interest to improve prognosis of patients suffering of advanced or recurrent endometrial cancer. This review describes the current evidence of molecular mechanisms in endometrial CSCs with special emphasis on MYC and NF-κB signaling as well as mitochondrial metabolism. Furthermore, the current status of immunotherapy targeting PD-1 and PD-L1 in endometrial cancer cells and CSCs is elucidated. The outlined findings encourage novel therapies that target signaling pathways in endometrial CSCs as well as immunotherapy as a promising therapeutic approach in the treatment of endometrial cancer to impede cancer progression and prevent recurrence.

The Diminishment of Novel Endometrial Carcinoma-Derived Stem-like Cells by Targeting Mitochondrial Bioenergetics and MYC

Cancer stem cells (CSCs) are a small subpopulation of tumor cells harboring properties that include self-renewal, multi-lineage differentiation, tumor reconstitution, drug resistance and invasiveness, making them key players in tumor relapse. In the present paper, we develop new CSC models and analyze the molecular pathways involved in survival to identify targets for the establishment of novel therapies. Endometrial carcinoma-derived stem-like cells (ECSCs) were isolated from carcinogenic gynecological tissue and analyzed regarding their expression of prominent CSC markers. Further, they were treated with the MYC-signaling inhibitor KJ-Pyr-9, chemotherapeutic agent carboplatin and type II diabetes medication metformin. ECSC populations express common CSC markers, such as Prominin-1 and CD44 antigen as well as epithelial-to-mesenchymal transition markers, Twist, Snail and Slug, and exhibit the ability to form free-floating spheres. The inhibition of MYC signaling and treatment with carboplatin as well as metformin significantly reduced the cell survival of ECSC-like cells. Further, treatment with metformin significantly decreased the mitochondrial membrane potential of ECSC-like cells, while the extracellular lactate concentration was increased. The established ECSC-like populations represent promising in vitro models to further study the contribution of ECSCs to endometrial carcinogenesis. Targeting MYC signaling as well as mitochondrial bioenergetics has shown promising results in the diminishment of ECSCs, although molecular signaling pathways need further investigations.

The IVF-generated human embryonic microenvironment reverses progestin resistance in endometrial cancer cells by inducing cancer stem cell differentiation

Progestin resistance is a critical factor that prevents patients with endometrial cancer (EC) from receiving conservative therapy. However, the etiology remains elusive. Cancer stem cells (CSCs) may be a contributing factor to progestin resistance in EC. These cells share similar stemness properties with embryonic stem cells that have a multipotent but differential naïve phenotype. Embryonic stem cells are programed to self-renew, to differentiate and to show plasticity toward a normal cellular phenotype in their defined microenvironment. However, whether this microenvironment may promote CSC differentiation toward a better responsive phenotype and reverse progestin resistance has not yet been clarified. In the current study, we found that progestin resistance of endometrial CSCs can be improved or reversed by using in vitro fertilization (IVF)-generated embryonic sac-derived fluid containing the embryonic microenvironment. Furthermore, suppression or reversal of progestin resistance was mediated by placental alkaline phosphatase (ALPP), a factor secreted into the embryonic microenvironment by IVF-generated blastocysts. ALPP significantly reversed progestin resistance by facilitating endometrial CSC differentiation through downregulating the stemness genes NANOG, OCT4 and SOX2. We further showed that the downregulation of NANOG, OCT4 and SOX2 by ALPP was carried out by TET1/2-mediated epigenetic modulation of the promoter regions of these genes. Such changes at the molecular level initiated endometrial CSC differentiation and promoted a better responsive endometrial cancer phenotype. In fact, their response to progestin treatment was similar to that of well-differentiated endometrioid carcinoma cells without CSCs. ALPP could be a novel target in the process to overcome progestin resistance, and such findings may provide a new approach for the conservative treatment of endometrial cancer.

Changes in Stem Cell Regulation and Epithelial Organisation during Carcinogenesis and Disease Progression in Gynaecological Malignancies

Simple Summary

Recent advances in our understanding of the stem cell potential in adult tissues have far-reaching implications for cancer research, and this creates new opportunities for the development of new therapeutic strategies. Here we outline changes in stem cell biology that characterize main gynaecological malignancies, ovarian, endometrial, and cervical cancer, and focus on specific differences between them. We highlight the importance of the local niche environment as a driver of malignant transformation in addition to mutations in key cancer-driving genes. Patient-derived organoids capture in vitro main aspects of cancer tissue architecture and stemness regulatory mechanisms, thus providing a valuable new platform for a personalized approach in the treatment of gynecological malignancies. This review summarizes the main achievement and formulates remaining open questions in this fast-evolving research field.

Abstract

Gynaecological malignancies represent a heterogeneous group of neoplasms with vastly different aetiology, risk factors, molecular drivers, and disease outcomes. From HPV-driven cervical cancer where early screening and molecular diagnostics efficiently reduced the number of advanced-stage diagnosis, prevalent and relatively well-treated endometrial cancers, to highly aggressive and mostly lethal high-grade serous ovarian cancer, malignancies of the female genital tract have unique presentations and distinct cell biology features. Recent discoveries of stem cell regulatory mechanisms, development of organoid cultures, and NGS analysis have provided valuable insights into the basic biology of these cancers that could help advance new-targeted therapeutic approaches. This review revisits new findings on stemness and differentiation, considering main challenges and open questions. We focus on the role of stem cell niche and tumour microenvironment in early and metastatic stages of the disease progression and highlight the potential of patient-derived organoid models to study key events in tumour evolution, the appearance of resistance mechanisms, and as screening tools to enable personalisation of drug treatments.

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.

GYNOCARE Update: Modern Strategies to Improve Diagnosis and Treatment of Rare Gynecologic Tumors—Current Challenges and Future Directions

Simple Summary

More than 50% of all the tumors affecting the female genital tract can be classified as rare and usually have a poor prognosis owing to delayed diagnosis and treatment. Currently, gynecologic cancer research, due to distinct scientific and technological challenges, is lagging behind. Moreover, the overall efforts for addressing these challenges are fragmented across different countries. The European Network for Gynecological Rare Cancer Research: GYNOCARE aims to address these challenges by creating a unique network between key stakeholders covering distinct domains from basic research to cure. GYNOCARE is part of a European Collaboration in Science and Technology (COST) with the aim to focus on the development of new approaches to improve the diagnosis and treatment of rare gynecological tumors. Here, we provide a brief overview describing the goals of this COST Action and its future challenges with the aim to continue fighting against this rare cancer.

Abstract

More than 50% of all gynecologic tumors can be classified as rare (defined as an incidence of ≤6 per 100,000 women) and usually have a poor prognosis owing to delayed diagnosis and treatment. In contrast to almost all other common solid tumors, the treatment of rare gynecologic tumors (RGT) is often based on expert opinion, retrospective studies, or extrapolation from other tumor sites with similar histology, leading to difficulty in developing guidelines for clinical practice. Currently, gynecologic cancer research, due to distinct scientific and technological challenges, is lagging behind. Moreover, the overall efforts for addressing these challenges are fragmented across different European countries and indeed, worldwide. The GYNOCARE, COST Action CA18117 (European Network for Gynecological Rare Cancer Research) programme aims to address these challenges through the creation of a unique network between key stakeholders covering distinct domains from concept to cure: basic research on RGT, biobanking, bridging with industry, and setting up the legal and regulatory requirements for international innovative clinical trials. On this basis, members of this COST Action, (Working Group 1, “Basic and Translational Research on Rare Gynecological Cancer”) have decided to focus their future efforts on the development of new approaches to improve the diagnosis and treatment of RGT. Here, we provide a brief overview of the current state-of-the-art and describe the goals of this COST Action and its future challenges with the aim to stimulate discussion and promote synergy across scientists engaged in the fight against this rare cancer worldwide.

Tumor-Targeting Peptides Search Strategy for the Delivery of Therapeutic and Diagnostic Molecules to Tumor Cells

Background: The combination of the unique properties of cancer cells makes it possible to find specific ligands that interact directly with the tumor, and to conduct targeted tumor therapy. Phage display is one of the most common methods for searching for specific ligands. Bacteriophages display peptides, and the peptides themselves can be used as targeting molecules for the delivery of diagnostic and therapeutic agents. Phage display can be performed both in vitro and in vivo. Moreover, it is possible to carry out the phage display on cells pre-enriched for a certain tumor marker, for example, CD44 and CD133. Methods: For this work we used several methods, such as phage display, sequencing, cell sorting, immunocytochemistry, phage titration. Results: We performed phage display using different screening systems (in vitro and in vivo), different phage libraries (Ph.D-7, Ph.D-12, Ph.D-C7C) on CD44+/CD133+ and without enrichment U-87 MG cells. The binding efficiency of bacteriophages displayed tumor-targeting peptides on U-87 MG cells was compared in vitro. We also conducted a comparative analysis in vivo of the specificity of the accumulation of selected bacteriophages in the tumor and in the control organs (liver, brain, kidney and lungs). Conclusions: The screening in vivo of linear phage peptide libraries for glioblastoma was the most effective strategy for obtaining tumor-targeting peptides providing targeted delivery of diagnostic and therapeutic agents to glioblastoma.

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.

An immune competent orthotopic model of endometrial cancer with metastasis

Endometrial cancer is the most common gynecologic malignancy in the U.S. with metastatic disease remaining the major cause of patient death. Therapeutic strategies have remained essentially unchanged for decades. A significant barrier to progression in treatment modalities stems from a lack of clinically applicable in vivo models to accurately mimic endometrial cancer; specifically, ones that form distant metastases and maintain an intact immune system. To address this problem, we have established the first immune competent murine orthotopic tumor model for metastatic endometrial cancer by creating a green fluorescent protein labeled cell line from an endometrial cancer that developed in a Pgr ^cre/+ Pten ^f/f Kras ^G12D genetically engineered mouse. These cancer cells were grafted into the abraded uterine lumen of ovariectomized recipient mice treated with estrogen and subsequently developed local and metastatic endometrial tumors. We noted primary tumor formation in 59% mixed background and 86% of C57BL/6 animals at 4 weeks and distant lung metastases in 78% of mice after 2 months. This immunocompetent orthotopic tumor model closely resembles some human metastatic endometrial cancer, modeling both local metastasis and hematogenous spread to lung and has significant potential to advance the study of endometrial cancer and its metastasis.

Endometrial Cancer Stem Cells: Role, Characterization and Therapeutic Implications

Endometrial cancer (EC) is the most frequent gynecological cancer. In patients with relapsed and advanced disease, prognosis is still dismal and development of resistance is common. In this context, endometrial Cancer Stem Cells (eCSC), stem-like cells capable to self-renewal and differentiation in mature cancer cells, represent a potential field of expansion for drug development. The aim of this review is to characterize the role of eCSC in EC, their features and how they could be targeted. CSC are involved in progression, invasiveness and metastasis (though epithelial to mesenchimal transition, EMT), as well as chemoresistance in EC. Nevertheless, isolation of eCSC is still controversial. Indeed, CD133, Aldheyde dehydrogenase (ALDH), CD117, CD55 and CD44 are enriched in CSCs but there is no universal marker nowadays. The most frequently activated pathways in eCSC are Wingless-INT (Wnt)/β-catenin, Notch1, and Hedghog, with a high expression of self-renewal transcription factors like Octamer binding transcription factor 4 (OCT), B Lymphoma Mo-MLV Insertion Region 1 Homolog (BMI1), North American Network Operations Group Homebox protein (NANOG), and SRY-Box 2 (SOX2). These pathways have been targeted with selective drugs alone or in combination with chemotherapy and immunotherapy. Unfortunately, although preclinical results are encouraging, few clinical data are available.

Unique Molecular Features in High-Risk Histology Endometrial Cancers

Endometrial cancer is the most common gynecologic malignancy in the United States and the sixth most common cancer in women worldwide. Fortunately, most women who develop endometrial cancer have low-grade early-stage endometrioid carcinomas, and simple hysterectomy is curative. Unfortunately, 15% of women with endometrial cancer will develop high-risk histologic tumors including uterine carcinosarcoma or high-grade endometrioid, clear cell, or serous carcinomas. These high-risk histologic tumors account for more than 50% of deaths from this disease. In this review, we will highlight the biologic differences between low- and high-risk carcinomas with a focus on the cell of origin, early precursor lesions including atrophic and proliferative endometrium, and the potential role of stem cells. We will discuss treatment, including standard of care therapy, hormonal therapy, and precision medicine-based or targeted molecular therapies. We will also discuss the impact and need for model systems. The molecular underpinnings behind this high death to incidence ratio are important to understand and improve outcomes.

ALDH-Dependent Glycolytic Activation Mediates Stemness and Paclitaxel Resistance in Patient-Derived Spheroid Models of Uterine Endometrial Cancer

Uterine endometrial cancer is associated with poor survival outcomes in patients with advanced-stage disease. Here, we developed a three-dimensional cell cultivation method of endometrioid cancer stem-like cells with high aldehyde dehydrogenase (ALDH) activity from clinical specimens. ALDH inhibition synergized with paclitaxel to block cancer proliferation. In the clinical setting, high ALDH1A1 expression was associated with poor survival. A high level of ALDH correlated with an increase of glucose uptake, activation of the glycolytic pathway, and elevation of glucose transporter 1 (GLUT1). Blockade of GLUT1 inhibited characteristics of cancer stem cells. Similarly to ALDH inhibition, GLUT1 inhibition synergized with paclitaxel to block endometrial cancer proliferation. Our data indicated that ALDH-dependent GLUT1 activation and the resulting glycolytic activation are of clinical importance for both prognostic evaluation and therapeutic decision-making in endometrial cancer patients. In addition, the synergistic effects of taxane compounds and ALDH or GLUT1 inhibitors may serve as a new clinical treatment option for endometrial cancer.

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Establishment of patient-derived endometrial cancer stem cells with ALDH activity

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Endometrial cancer stemness depends on ALDH-mediated glycolysis via GLUT1

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High ALDH and GLUT expression is associated with poor outcome in endometrial cancer

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Paclitaxel and ALDH or GLUT inhibitor synergistically suppress endometrial cancer

The role of myeloid-derived suppressor cells in endometrial cancer displaying systemic inflammatory response: clinical and preclinical investigations

Systemic inflammatory responses including thrombocytosis, leukocytosis, or neutrophilia have gained attention as prognostic indicators in patients with various solid malignancies.current study, we aimed to investigate the clinical implications and underlying biological mechanism of the systemic inflammatory response in endometrial cancer. Clinical data from 900 patients with endometrial cancer were analyzed to investigate the association between pretreatment leukocytosis, thrombocytosis, and treatment outcome. Clinical samples, endometrial cancer cell lines, and a mouse model of endometrial cancer were used to examine the mechanisms responsible for systemic inflammatory response in endometrial cancer, focusing on the role of tumor-derived granulocyte colony-stimulating factor (G-CSF) and MDSCs. Then, we showed that pretreatment concurrent leukocytosis and thrombocytosis is associated with significantly shorter survival and decreased chemosensitivity among patients with endometrial cancer. In vitro and in vivo experiments revealed that tumor-derived G-CSF and G-CSF-mediated IL-6 production from the tumor microenvironment are involved in the development of leukocytosis and thrombocytosis in patients with endometrial cancer. Moreover, increased tumor-infiltrating MDSCs induced by tumor-derived G-CSF, MDSC-mediated T cell suppression, and MDSC-mediated cancer stem cell induction are responsible for progression and chemoresistance in this type of endometrial cancer. MDSC depletion using an anti-Gr-1 neutralizing antibody or inhibition of MDSC activity by celecoxib inhibited tumor growth and enhanced chemosensitivity in endometrial cancer displaying concurrent leukocytosis and thrombocytosis. In conclusion, Pretreatment concurrent leukocytosis and thrombocytosis are associated with significantly shorter survival and decreased chemosensitivity among patients with endometrial cancer. Combining MDSC-targeting treatments with current standard chemotherapies might have therapeutic efficacy for these patients.

Expression of CD133 is associated with poor prognosis in stage II colorectal carcinoma

CD133 is currently believed to be one of the best colorectal cancer stem cell markers. This study aimed to evaluate prognostic significance of CD133 expression in colorectal cancer patients.A total of 303 patients with stage I to III colorectal cancer who underwent curative surgical resection from 2003 to 2008 at a single institution were included. CD133 expression was evaluated using immunohistochemical staining, and clinicopathological data were retrospectively reviewed. The patients were dichotomized after scoring CD133 expression (0 to 2+: low CD133 expression vs 3+ to 4+: high CD133 expression) according to the extent of area of CD133 positive tumor cells (<50% vs ≥50%) and pattern of staining (membranous staining of the luminal surface and/or staining of cellular debris in the tumor glands and cytoplasm).The 5-year overall survival (OS) (61.9% vs 80.2%, P = .001) and disease-free survival (64.8% vs 75.8%, P = .026) were poorer in the high CD133 expression group than the low CD133 expression group. In the multivariate analysis for risk factors of OS in the whole population, higher nodal stage (N2 compared to N0: hazard ratio [HR] 3.141; 95% confidence interval [CI] 1.718-5.744, P < .001), perineural invasion (HR 2.262; 95% CI 1.347-3.798, P = .002) and high CD133 expression (HR 1.929; 95% CI 1.221-3.048, P = .005) were independent poor prognostic factors of OS. Subgroup analyses according to each TNM stage revealed that CD133 expression was associated with OS only within the stage II patients (HR 3.167 95% CI 1.221-8.216, P = .018). Furthermore, the stage II patients demonstrating the high CD133 expression showed survival benefit of adjuvant chemotherapy, regardless of high-risk feature positivity (HR 0.201 95% CI 0.054-0.750, P = .017).High CD133 expression is correlated with poor prognosis in colorectal cancer patients after radical resection. The CD133 expression may serve as a more potent and informative biomarker for prognosis than conventional high-risk features in the stage II colorectal cancer patients.

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis

STUDY QUESTION

Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

STUDY ANSWER

We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

WHAT IS KNOWN ALREADY

Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

STUDY DESIGN, SIZE, DURATION

CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

MAIN RESULTS AND THE ROLE OF CHANCE

Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASON FOR CAUTION

As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

Targeting Endometrial Cancer Stem Cell Activity with Metformin Is Inhibited by Patient-Derived Adipocyte-Secreted Factors

Advanced endometrial cancer continues to have a poor prognosis, due to limited treatment options, which may be further adversely impacted by obesity. Endometrial cancer stem cells have been reported to drive metastasis, chemotherapy resistance and disease relapse, but have yet to be fully characterised and no specific targeted therapies have been identified. Here, we describe the phenotype and genotype of aldehyde dehydrogenase high (ALDH^high) and CD133^+ve endometrial cancer stem cells and how adipocyte secreted mediators block the inhibitory effect of metformin on endometrial cancer stem cell activity. Ishikawa and Hec-1a cell lines were used to characterise ALDH^high and CD133^+ve endometrial cancer cells using flow cytometry, functional sphere assays and quantitative-Polymerase Chain Reaction. The comparative effect of metformin on endometrial cancer stem cell activity and bulk tumour cell proliferation was determined using an Aldefluor and cytotoxicity assay. The impact of adipocyte secreted mediators on metformin response was established using patient-derived conditioned media. ALDH^high cells demonstrated greater endometrial cancer stem cell activity than CD133^+ve cells and had increased expression of stem cell and epithelial-mesenchymal transition genes. Treatment with 0.5-1 mM metformin reduced the proportion and activity of both endometrial cancer stem cell populations (p ≤ 0.05), without affecting cell viability. This effect was, however, inhibited by exposure to patient-derived adipocyte conditioned media. These results indicate a selective and specific effect of metformin on endometrial cancer stem cell activity, which is blocked by adipocyte secreted mediators. Future studies of metformin as an adjuvant therapy in endometrial cancer should be adequately powered to investigate the influence of body mass on treatment response.

Fabrication of Chitosan/Polypyrrole‐coated poly(L‐lactic acid)/Polycaprolactone aligned fibre films for enhancement of neural cell compatibility and neurite growth

Objective

Methods

Results

Conclusions

Targeting cancer stem cell signature gene SMOC-2 Overcomes chemoresistance and inhibits cell proliferation of endometrial carcinoma

Background

Endometrial cancer is one of the most common gynecological malignancies and has exhibited an increasing incidence rate in recent years. Cancer stem cells (CSCs), which are responsible for tumor growth and chemoresistance, have been confirmed in endometrial cancer. However, it is still challenging to identify endometrial cancer stem cells to then target for therapy.

Methods

Flow cytometry was used to identify the endometrial cancer stem cells. Sphere formation assay, western blotting, qRT-PCR assay, cell viability assay, xenograft assay and immunohistochemistry staining analysis were utilized to evaluate the effect of SPARC-related modular calcium binding 2 (SMOC-2) on the cells proliferation and drug resistance. Cell viability assay, qRT-PCR assay, immunofluorescence staining, Co-IP assay and luciferase reporter gene assay were performed to explore the possible molecular mechanism by which SMOC-2 activates WNT/β-catenin pathway.

Findings

We found the expression of SPARC-related modular calcium binding 2 (SMOC-2), a member of SPARC family, was higher in endometrial CSCs than that in non-CSCs. SMOC-2 was also more highly expressed in spheres than in monolayer cultures. The silencing of SMOC-2 suppressed cell sphere ability; reduced the expression of the stemness-associated genes SOX2, OCT4 and NANOG; and enhanced chemosensitivity in endometrial cancer cells. By co-culture IP assay, we demonstrated that SMOC-2 directly interacted with WNT receptors (Fzd6 and LRP6), enhanced ligand-receptor interaction with canonical WNT ligands (Wnt3a and Wnt10b), and finally, activated the WNT/β-catenin pathway in endometrial cancer. SMOC-2 expression was closely correlated with CSC markers CD133 and CD44 expression in endometrial cancer tissue.

Interpretation

Taken together, we conclude that SMOC-2 might be a novel endometrial cancer stem cell signature gene and therapeutic target for endometrial cancer.

Fund

National Natural Science Foundation of China, Scientific and Technological Innovation Act Program of Shanghai Science and Technology Commission, Scientific and Technological Innovation Act Program of Fengxian Science and Technology Commission, Natural Science Foundation of Shanghai.

Endometrial Cancer Spheres Show Cancer Stem Cells Phenotype and Preference for Oxidative Metabolism

This study aimed to characterize endometrial cancer regarding cancer stem cells (CSC) markers, regulatory and differentiation pathways, tumorigenicity and glucose metabolism. Endometrial cancer cell line ECC1 was submitted to sphere forming protocols. The first spheres generation (ES1) was cultured in adherent conditions (G1). This procedure was repeated and was obtained generations of spheres (ES1, ES2 and ES3) and spheres-derived cells in adherent conditions (G1, G2 and G3). Populations were characterized regarding CD133, CD24, CD44, aldehyde dehydrogenase (ALDH), hormonal receptors, HER2, P53 and β-catenin, fluorine-18 fluorodeoxyglucose ([¹⁸F]FDG) uptake and metabolism by NMR spectroscopy. An heterotopic model evaluated differential tumor growth. The spheres self-renewal was higher in ES3. The putative CSC markers CD133, CD44 and ALDH expression were higher in spheres. The expression of estrogen receptor (ER)α and P53 decreased in spheres, ERβ and progesterone receptor had no significant changes and β-catenin showed a tendency to increase. There was a higher ¹⁸F-FDG uptake in spheres, which also showed a lower lactate production and an oxidative cytosol status. The tumorigenesis in vivo showed an earlier growth of tumours derived from ES3. Endometrial spheres presented self-renewal and differentiation capacity, expressed CSC markers and an undifferentiated phenotype, showing preference for oxidative metabolism.

Regulation of Sox2 and stemness by nicotine and electronic-cigarettes in non-small cell lung cancer

Background

Lung cancer is the leading cause of cancer related deaths and its incidence is highly correlated with cigarette smoking. Nicotine, the addictive component of tobacco smoke, cannot initiate tumors, but can promote proliferation, migration, and invasion of cells in vitro and promote tumor growth and metastasis in vivo. This nicotine-mediated tumor promotion is facilitated through the activation of nicotinic acetylcholine receptors (nAChRs), specifically the α7 subunit. More recently, nicotine has been implicated in promoting self-renewal of stem-like side-population cells from lung cancers. This subpopulation of cancer stem-like cells has been implicated in tumor initiation, generation of the heterogeneous tumor population, metastasis, dormancy, and drug resistance. Here we describe the molecular events driving nicotine and e-cigarette extract mediated stimulation of self-renewal of stem-like cells from non-small cell lung cancer.

Methods

Experiments were conducted using A549 and H1650 non-small cell lung cancer cell lines and human mesenchymal stem cells according to protocols described in this paper. 2 μM nicotine or e-cigarette extracts was used in all relevant experiments. Biochemical analysis using western blotting, transient transfections, RT-PCR and cell biological analysis using double immunofluorescence and confocal microscopy, as well as proximity ligation assays were conducted.

Results

Here we demonstrate that nicotine can induce the expression of embryonic stem cell factor Sox2, which is indispensable for self-renewal and maintenance of stem cell properties in non-small cell lung adenocarcinoma (NSCLC) cells. We further demonstrate that this occurs through a nAChR-Yap1-E2F1 signaling axis downstream of Src and Yes kinases. Our data suggests Oct4 may also play a role in this process. Over the past few years, electronic cigarettes (e-cigarettes) have been promoted as healthier alternatives to traditional cigarette smoking as they do not contain tobacco; however, they do still contain nicotine. Hence we have investigated whether e-cigarette extracts can enhance tumor promoting properties similar to nicotine; we find that they can induce expression of Sox2 as well as mesenchymal markers and enhance migration and stemness of NSCLC cells.

Conclusions

Our findings shed light on novel molecular mechanisms underlying the pathophysiology of smoking-related lung cancer in the context of cancer stem cell populations, and reveal new pathways involved that could potentially be exploited therapeutically.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0901-2) contains supplementary material, which is available to authorized users.

Targeting Breast Cancer Stem Cells to Overcome Treatment Resistance

Despite advances in breast cancer diagnosis and treatment, many patients still fail therapy, resulting in disease progression, recurrence, and reduced overall survival. Historically, much focus has been put on the intrinsic subtyping based in the presence (or absence) of classical immunohistochemistry (IHC) markers such as estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-related protein (HER2). However, it is widely understood that tumors are composed of heterogeneous populations of cells with a hierarchical organization driven by cancer stem cells (CSCs). In breast tumors, this small population of cells displaying stem cell properties is known as breast CSCs (BCSCs). This rare population exhibit a CD44⁺/CD24-/low phenotype with high ALDH activity (ALDH⁺), and possesses higher tolerability to chemotherapy, hormone therapy, and radiotherapy and is able to reproduce the bulk of the tumor after reduction of cell populations sensitive to first-line therapy leading to disease relapse. In this review, we present special attention to BCSCs with future directions in the establishment of a therapy targeting this population. Drugs targeting the main BCSCs signaling pathways undergoing clinical trials are also summarized.

Evaluation of Vav3.1 as prognostic marker in endometrial cancer

PURPOSE

Vav3 is a guanine nucleotide exchange factor that regulates the activity of Rho/Rac family GTPases. In a study on ovarian cancer, we recently demonstrated pronounced prognostic and predictive value of Vav3.1, a specific truncation variant of the parental Vav3 gene. Here, we sought to investigate the role of Vav3.1 in the most prevalent gynecological tumor entity, endometrial cancer.

METHODS

Vav3.1 transcript levels were determined in a large cohort of endometrial cancer patients using variant-specific PCR (n = 239), and non-malignant endometrial tissue served as control (n = 26). Expression levels of Vav3.1 were stratified according to established clinicopathological characteristics and correlated to long-term patient survival (average follow-up of > 7.5 years). Type 1 and type 2 cancers were separately investigated.

RESULTS

While Vav3.1 was markedly overexpressed in endometrial cancer tissue, we could not detect associations with clinical parameters related to prognosis, such as FIGO stage and tumor grade. Kaplan-Meier estimators of different measures of survival failed to show prognostic significance of Vav3.1 in endometrial cancer. Lack of prognostic value was observed for both type 1 and type 2 cancers.

CONCLUSIONS

Our study shows that Vav3.1 is not suited as a marker of cancer progression and/or treatment response in endometrial cancer. Feasibility and potential benefit of targeting Vav3.1 in endometrial cancer needs to be evaluated in future studies, proceeding from its clear, roughly ten-fold, induction in the malignant endometrium.

Soft agar-based selection of spontaneously transformed rat prostate epithelial cells with highly tumorigenic characteristics

The critical molecular and cellular mechanisms involved in the development and progression of prostate cancer remain elusive. In this report, we demonstrate that normal rat prostate epithelial cells (PEC) undergo spontaneous transformation at high passage (p > 85) evidenced by the acquisition of anchorage independent growth when plated on soft agar and tumorigenicity when injected into immunodeficient mice. In addition, we also report the discovery of a minor subpopulation of spontaneously transformed PEC derived from high passage PEC with the ability to migrate through a layer of 1% agar and form expanding colonies on the underlying plastic substratum. Comparison of these soft agar invasive (SAI) cells with low (p < 35), mid (p36-84) and high passage (p > 85) PEC identified marked differences in cell morphology, proliferation and motility. The SAI subpopulation was more tumorigenic than the high passage anchorage independent cultures from which they were isolated, as manifested by a decreased latency period and an increase in the size of tumors arising in immunodeficient mice. In contrast, low and mid passage cells were unable to grow on soft agar and failed to form tumors when injected into immunodeficient mice. Screening with antibody-based signaling arrays identified several differences in the altered expression levels of signaling proteins between SAI-derived cells and low or high passage PEC, including the up-regulation of EGFR and MAPK-related signaling pathways in SAI-selected cells. In summary, these studies suggest that the SAI assay selects for a novel, highly tumorigenic subpopulation of transformed cells that may represent an early step in the progression of slow growing prostatic carcinomas into more rapidly growing and aggressive tumors.

Targeting Leukemia Stem Cells in the Bone Marrow Niche

Abstract: The bone marrow (BM) niche encompasses multiple cells of mesenchymal and hematopoietic origin and represents a unique microenvironment that is poised to maintain hematopoietic stem cells. In addition to its role as a primary lymphoid organ through the support of lymphoid development, the BM hosts various mature lymphoid cell types, including naïve T cells, memory T cells and plasma cells, as well as mature myeloid elements such as monocyte/macrophages and neutrophils, all of which are crucially important to control leukemia initiation and progression. The BM niche provides an attractive milieu for tumor cell colonization given its ability to provide signals which accelerate tumor cell proliferation and facilitate tumor cell survival. Cancer stem cells (CSCs) share phenotypic and functional features with normal counterparts from the tissue of origin of the tumor and can self-renew, differentiate and initiate tumor formation. CSCs possess a distinct immunological profile compared with the bulk population of tumor cells and have evolved complex strategies to suppress immune responses through multiple mechanisms, including the release of soluble factors and the over-expression of molecules implicated in cancer immune evasion. This chapter discusses the latest advancements in understanding of the immunological BM niche and highlights current and future immunotherapeutic strategies to target leukemia CSCs and overcome therapeutic resistance in the clinic.

Cancer stem cells CD133 inhibition and cytotoxicity of certain 3-phenylthiazolo[3,2-a]benzimidazoles: design, direct synthesis, crystal study and in vitro biological evaluation

Cancer stem cells (CSCs) have been objects of intensive study since their identification in 1994. Adopting a structural rigidification approach, a novel series of 3-phenylthiazolo[3,2-a]benzimidazoles 4a-d was designed and synthesised, in an attempt to develop potent anticancer agent that can target the bulk of tumour cells and CSCs. The anti-proliferative activity of the synthesised compounds was evaluated against two cell lines, namely; colon cancer HT-29 and triple negative breast cancer MDA-MB-468 cell lines. Also, their inhibitory activity against the cell surface expression of CD133 was examined. In particular, compound 4b emerged as a promising hit molecule as it manifested good antineoplastic potency against both tested cell lines (IC50 = 9 and 12 μM, respectively), beside its ability to inhibit the cell surface expression of CD133 by 50% suggesting a promising potential of effectively controlling the tumour by eradicating the tumour bulk and inhibiting the proliferation of the CSCs. Moreover, compounds 4a and 4c showed moderate activity against HT-29 (IC50 = 21 and 29 μM, respectively) and MDA-MB-468 (IC50 = 23 and 24 μM, respectively) cell lines, while they inhibited the CD133 expression by 14% and 48%, respectively. Finally, a single crystal X-ray diffraction was recorded for compound 4d.

MicroRNA-34a inhibits cells proliferation and invasion by downregulating Notch1 in endometrial cancer

MicroRNAs (miRNAs) are small non-coding RNAs composed of 18-25 nucleotides that regulate the expression of approximately 30% of human protein coding genes. Dysregulation of miRNAs plays a pivotal role in the initiation and progression of malignancies. Our study has shown that microRNA-34a (miR-34a) was upregulated in human endometrial cancer stem cells (ECSCs). However, it is unknown how miR-34a regulates endometrial cancer itself. Here, we report that miR-34a directly and functionally targeted Notch1. MiR-34a inhibited the proliferation, migration, invasion, EMT-associated phenotypes by downregulating Notch1 in endometrial cancer cells. Overexpression of miR-34a also suppressed tumor growth in nude mice. Importantly, further results suggested miR-34a was significantly downregulated in endometrial cancer tissues and negatively correlated with Notch1 expression. There was a significant association between decreased miR-34a expression and worse patient prognosis. Taken together, our results suggest that miR-34a plays tumor-suppressive roles in endometrial cancer through downregulating Notch1. Thus miR-34a could be a potential therapeutic target for prevention and treatment of endometrial cancer.

Isolation of Stem-Like Cancer Cells in Primary Endometrial Cancer Using Cell Surface Markers CD133 and CXCR4

Endometrial cancer (EC) is the most common familiar gynecologic malignant tumor identified in the female reproductive system and has been increasing yearly. In this study, we will identify the surface markers and stem cell markers related with cancer stem cells (CSCs) of EC. Tissue samples were obtained from endometrial cancer patients during surgical procedures. Single cells were isolated from the tissues for culturing, transfection into nude mice, and histopathology analysis. RT-PCR demonstrated that the cultured cells strongly expressed stemness-related genes, such as c-Myc, Sox-2, Nanog, Oct 4A, ABCG2, BMI-1, CK-18, Nestin and β-actin. The expression of surface markers CD24, CD133, CD47, CD29, CD44, CXCR4, SSEA3 and SSEA4, CD24, and CD133 and chemokine markers such as CXCR4 were measured by flow cytometry. Then the double percentage of CD133+CXCR4+ cells constituted 7.2% and 9.3% in EC cells originated from two different patients, respectively. The CD133+CXCR4+ primary endometrial cancer cells grew faster, exhibited high expression of mRNA of stemness-related genes, produced more spheres, and had higher clonogenic ability than other subpopulations. They are also more resistant to anti-cancer drugs than other subpopulations. These findings indicate that CD133+CXCR4+ cells may possess some characteristics of CSCs in primary endometrial cancer. These cell surface markers may be useful for the development of drugs against CSC molecular targets or as a predictive marker for poor prognosis in primary endometrial cancer.

Association between Morphological Patterns of Myometrial Invasion and Cancer Stem Cell Markers in Endometrial Endometrioid Carcinoma

In endometrial endometrioid adenocarcinoma (EEC), the depth of myometrial invasion (MI) is an important parameter for determining whether additional treatment is warranted. The present study investigated the association between MI patterns, cancer stem cell (CSC) phenotypes, and their clinicopathological significance in EEC. A total of 73 cases of EEC with MI were examined in this study. Haematoxylin and eosin-stained tissue specimens were analysed for MI pattern, which was categorised as infiltrating; expansile; adenomyosis (AM)-like; or microcystic, elongated, and fragmented (MELF)-type. The expression of CSC markers such as cluster of differentiation (CD)44, CD133, and Nanog1, as well as oestrogen receptor (ER) and progesterone receptor (PR) was examined by immunohistochemistry. Clinicopathological features including age, DOI, MI pattern, LVI, lymph node (LN) metastasis, disease progression, and survival outcome were recorded. Most examined cases (45/73) were International Federation of Gynecology and Obstetrics (FIGO) stage I. MI showed infiltrating (49.3%), AM-like (26.3%), MELF (15.1%), and expansile (9.6%) patterns. Tumours with the infiltrating pattern were associated with high FIGO grade (P = 0.002), reduced ER and PR, and CD44 expression (P = 0.014, 0.026, and 0.030, respectively); those with a MELF pattern showed LN metastasis (P < 0.001), lymphovascular invasion (P = 0.011), and reduced ER, CD44, and CD133 expression (P = 0.036, 0.006, and 0.016, respectively). EEC with infiltrating/MELF patterns of MI is associated with worse prognosis. These results suggest that CSC expression profiles are an unfavourable indicator of EEC.

Peroxiredoxin 3 maintains the survival of endometrial cancer stem cells by regulating oxidative stress

Cancer stem cell (CSC)-targeted therapy could reduce tumor growth, recurrence, and metastasis in endometrial cancer (EC). The mitochondria of CSCs have been recently found to be an important target for cancer treatment, but the mitochondrial features of CSCs and their regulators, which maintain mitochondrial function, remain unclear. Here, we investigated the mitochondrial properties of CSCs, and identified specific targets for eliminating CSCs in EC. We found that endometrial CSCs displayed higher mitochondrial membrane potential, Ca²⁺, reactive oxygen species, ATP levels, and oxygen consumption rates than non-CSCs. Further, we also verified that mitochondrial peroxiredoxin 3 (Prx3) was upregulated, and that it contributed to the survival of CSCs in EC. The knockdown of the Prx3 gene resulted not only in decreased sphere formation, but also reduced the viability of endometrial CSCs, by causing mitochondrial dysfunction. Furthermore, we found that the forkhead box protein M1 (FoxM1), an important transcriptional factor, is overexpressed in patients with EC. FoxM1 expression correlates with elevated Prx3 expression levels, in agreement with the tumorigenic ability of Prx3 in endometrial CSCs. Taken together, our findings indicate that human endometrial CSCs have enhanced mitochondrial function compared to that of endometrial tumor cells. Endometrial CSCs show increased expression of the mitochondrial Prx3, which is required for the maintenance of mitochondrial function and survival, and is induced by FoxM1. Based on our findings, we believe that these proteins might represent valuable therapeutic targets and could provide new insights into the development of new therapeutic strategies for patients with endometrial cancer.

Prognostic impact of CD133 expression in Endometrial Cancer Patients

To assess the impact of CD133 expression on the prognosis of endometrioid endometrial carcinoma (EEC). We retrospectively assessed CD133 expression in tissue microarray of 116 surgically treated FIGO I-III EEC. Tumors with ≥10% of CD133-expressing cells were considered CD133-positive (CD133+). On the basis of CD133 expression, clinical and pathological parameters, progression-free survival (PFS) and overall survival (OS) were evaluated. Of the EEC studied 85.2% showed CD133-expressing cells. Only 61% (n = 66) of EEC presented ≥10% of CD133 expressing cells and were considered CD133+. The mean OS for CD133+ tumour patients was 161 months (95% CI, 154–168) as compared with 146 months (95% CI, 123–160) for those with CD133- tumors (p = 0.012). The mean PFS for CD133+ tumour was 159 months (95% CI, 149–168) as compared with 147 months (95% CI, 132-161) in those with a CD133-tumour (p = 0.014). CD133+ tumours were less likely to have vascular invasion (p = 0.010) and more likely to be well differentiated (p = 0.034). C133+ tumours predicted favorable OS and PFS of EEC patients, with a Hazard Ratio 4.731 (95% CI, 1.251–17.89; p = 0.022). CD133+ tumor status correlates with favorable prognosis of EEC. Our findings are in agreement with studies addressing brain and colorectal tumours.

Expression of CD133 in endometrial cancer cells and its implications

Cancer stem cells are an attractive therapeutic target for cancer. The present study examined stem cell characteristics of CD133+ cells isolated from endometrial cancer. Phenotypic characteristics, proliferation, migration, anchorage-independent growth, chemoresistance, gene expression profile and tumorigenicity of CD133+ tumor cells were assessed. Primary tumor exhibited immunoreactivity for CD133. Endometrial CD133+ tumor cells enhanced proliferation rate, colony formation, chemotaxis migration ability, and chemoresistance to cisplatin, paclitaxel, and doxorubicin than CD133- cells. CD133+ cells expressed more cancer stem cells markers such as EpCAM, aldehyde dehydrogenase 1 and insulin-like growth factor-1 receptor than CD133- cells. Moreover, CD133+ cells also increased expression of embryonic stem cell markers including oct4, nanog, sox2, and cmyc than CD133- cells. Finally, CD133+ tumor cells could generate xenograft but not CD133- tumor cells. CD133 and Ki67 were extensively expressed in the xenograft. In conclusion, endometrial CD133+ tumor cells displayed cancer stem cell characteristics and might represent a valuable tool for identifying endometrial cancer stem cells and hence a potential therapeutic target.

EMP2 is a novel therapeutic target for endometrial cancer stem cells

Previous studies have suggested that overexpression of the oncogenic protein epithelial membrane protein-2 (EMP2) correlates with endometrial carcinoma progression and ultimately poor survival from disease. To understand the role of EMP2 in the etiology of disease, gene analysis was performed to show transcripts that are reciprocally regulated by EMP2 levels. In particular, EMP2 expression correlates with and helps regulate the expression of several cancer stem cell associated markers including aldehyde dehydrogenase 1 (ALDH1). ALDH expression significantly promotes tumor initiation and correlates with the levels of EMP2 expression in both patient samples and tumor cell lines. As therapy against CSCs in endometrial cancer is lacking, the ability of anti-EMP2 IgG1 therapy to reduce primary and secondary tumor formation using xenograft HEC1A models was determined. Anti-EMP2 IgG1 reduced the expression and activity of ALDH and correspondingly reduced both primary and secondary tumor load. Our results collectively suggest that anti-EMP2 therapy may be a novel method of reducing endometrial cancer stem cells.

Targeting Cancer Stem Cells-A Renewed Therapeutic Paradigm

Metastasis is often accompanied by radio- and chemotherapeutic resistance to anticancer treatments and is the major cause of death in cancer patients. Better understanding of how cancer cells circumvent therapeutic insults and how disseminated cancer clones generate life-threatening metastases would therefore be paramount to the development of effective therapeutic approaches for clinical management of malignant disease. Mounting reports over the past two decades have provided evidence for the existence of a minor population of highly malignant cells within liquid and solid tumors, which are capable of self-renewing and of regenerating secondary growths with the heterogeneity of the primary tumors from which they derive. These cells, called tumor-initiating cells or cancer stem cells (CSCs) exhibit increased resistance to standard radio- and chemotherapies and appear to have mechanisms that enable them to evade immune surveillance. CSCs are therefore considered to be responsible for systemic residual disease after cancer therapy, as well as for disease relapse. How CSCs develop, the nature of the interactions they establish with their microenvironment, their phenotypic and functional characteristics, as well as their molecular dependencies have all taken center stage in cancer therapy. Indeed, improved understanding of CSC biology is critical to the development of important CSC-based anti-neoplastic approaches that have the potential to radically improve cancer management. Here, we summarize some of the most pertinent elements regarding CSC development and properties, and highlight some of the clinical modalities in current development as anti-CSC therapeutics.

Target Therapies for Uterine Carcinosarcomas: Current Evidence and Future Perspectives

Carcinosarcomas (CS) in gynecology are very infrequent and represent only 2-5% of uterine cancers. Despite surgical cytoreduction and subsequent chemotherapy being the primary treatment for uterine CS, the overall five-year survival rate is 30 ± 9% and recurrence is extremely common (50-80%). Due to the poor prognosis of CS, new strategies have been developed in the last few decades, targeting known dysfunctional molecular pathways for immunotherapy. In this paper, we aimed to gather the available evidence on the latest therapies for the treatment of CS. We performed a systematic review using the terms "uterine carcinosarcoma", "uterine Malignant Mixed Müllerian Tumors", "target therapies", "angiogenesis therapy", "cancer stem cell therapy", "prognostic biomarker", and "novel antibody-drug". Based on our results, the differential expression and accessibility of epithelial cell adhesion molecule-1 on metastatic/chemotherapy-resistant CS cells in comparison to normal tissues and Human Epidermal Growth Factor Receptor 2 (HER2) open up new possibilities in the field of target therapy. Nevertheless, future investigations are needed to clarify the impact of these new therapies on survival rate and medium-/long-term outcomes.

Dicer1 dysfunction promotes stemness and aggression in endometrial carcinoma

Endometrial carcinoma is one of the most common gynecological malignancies, but the molecular events involved in the development and progression of endometrial carcinoma remain unclear. Dicer1 and cancer stem cells play important roles in cell motility and survival. This study investigated the role of the let-7 family and Dicer1 in the stemness of endometrial carcinoma cells. We profiled Dicer1 expression in clinical samples and explored its relationship with stem cell-associated markers and clinical parameters. We showed that Dicer1 dysfunction leads to the enrichment of tumor stemness features and tumor aggression both in vitro and in vivo. We also identified the mechanism related to this potential tumor-predisposing phenotype: loss of Dicer1 induced abnormal expression of the let-7 family, which comprises well-known tumor suppressors, thus regulating stemness in endometrial carcinoma cells.

The Role of Hypoxia and Cancer Stem Cells in Renal Cell Carcinoma Pathogenesis

The cancer stem cell (CSC) model has recently been approached also in renal cell carcinoma (RCC). A few populations of putative renal tumor-initiating cells (TICs) were identified, but they are indifferently understood; however, the first and most thoroughly investigated are CD105-positive CSCs. The article presents a detailed comparison of all renal CSC-like populations identified by now as well as their presumable origin. Hypoxic activation of hypoxia-inducible factors (HIFs) contributes to tumor aggressiveness by multiple molecular pathways, including the governance of immature stem cell-like phenotype and related epithelial-to-mesenchymal transition (EMT)/de-differentiation, and, as a result, poor prognosis. Due to intrinsic von Hippel-Lindau protein (pVHL) loss of function, clear-cell RCC (ccRCC) develops unique pathological intra-cellular pseudo-hypoxic phenotype with a constant HIF activation, regardless of oxygen level. Despite satisfactory evidence concerning pseudo-hypoxia importance in RCC biology, its influence on putative renal CSC-like largely remains unknown. Thus, the article discusses a current knowledge of HIF-1α/2α signaling pathways in the promotion of undifferentiated tumor phenotype in general, including some experimental findings specific for pseudo-hypoxic ccRCC, mostly dependent from HIF-2α oncogenic functions. Existing gaps in understanding both putative renal CSCs and their potential connection with hypoxia need to be filled in order to propose breakthrough strategies for RCC treatment.

Cancer stem cells as a potential therapeutic target in thyroid carcinoma

A number of studies have indicated that tumor growth and proliferation is dependent on a small subset of cells, defined as cancer stem cells (CSCs). CSCs have the capability to self-renew, and are involved with cancer propagation, relapse and metastatic dissemination. CSCs have been isolated from numerous tissues, including normal and cancerous thyroid tissue. A regulatory network of signaling pathways and microRNAs (miRNAs) control the properties of CSCs. Differentiated thyroid carcinoma is the most common type of endocrine cancer, with an increasing incidence. Anaplastic thyroid carcinoma is the most rare type of endocrine cancer; however, it also exhibits the highest mortality rate among thyroid malignancies, with an extremely short survival time. Thyroid CSCs are invasive and highly resistant to conventional therapies, including radiotherapy and chemotherapy, which results in disease relapse even when the primary lesion has been eradicated. Therefore, targeting thyroid CSCs may represent an effective treatment strategy against aggressive neoplasms, including recurrent and radioresistant tumors. The present review summarizes the current literature regarding thyroid CSCs and discusses therapeutic strategies that target these cells, with a focus on the function of self-renewal pathways and miRNAs. Elucidation of the mechanisms that regulate CSC growth and survival may improve novel therapeutic approaches for treatment-resistant thyroid cancers.