New insights in endometrial carcinogenesis

Molecular Basis of Endometriosis and Endometrial Cancer: Current Knowledge and Future Perspectives

The human endometrium is a unique tissue undergoing important changes through the menstrual cycle. Under the exposure of different risk factors in a woman's lifetime, normal endometrial tissue can give rise to multiple pathologic conditions, including endometriosis and endometrial cancer. Etiology and pathophysiologic changes behind such conditions remain largely unclear. This review summarizes the current knowledge of the pathophysiology of endometriosis and its potential role in the development of endometrial cancer from a molecular perspective. A better understanding of the molecular basis of endometriosis and its role in the development of endometrial pathology will improve the approach to clinical management.

Long non‑coding RNA LINC01224 promotes cell proliferation and inhibits apoptosis by regulating AKT3 expression via targeting miR‑485‑5p in endometrial carcinoma

Endometrial carcinoma (EC) is the most common cancer in women worldwide, yet little is known about the underlying molecular basis of EC development. LINC01224, a novel long non-coding (lnc)RNA, was recently identified as an oncogene in various types of cancer. However, the function and underlying mechanism of LINC01224 in EC is still unclear. A total of 50 pairs of tumor and adjacent normal tissue from patients with EC, three EC cell lines and one human normal endometrial stromal cell (ESC) line were subjected to reverse transcription-quantitative PCR assay to evaluate the expression levels of LINC01224. Cell Counting Kit-8, colony formation and flow cytometry assays were used to assess cell proliferation and apoptosis. Western blotting was used to measure expression levels of apoptosis- and proliferation-associated proteins and AKT3 protein. A xenograft model of HEC1A cells was established to validate the in vivo function of LINC01224 in EC tumor growth. Starbase 3.0 database prediction and luciferase reporter and RNA pull-down assays were performed to verify the binding sites between LINC01224 and microRNA (miR)-485-5p and miR-485-5p and AKT3. LINC01224 expression was significantly upregulated in both EC tumor tissue and cell lines. The upregulation of LINC01224 was negatively associated with survival of patients with EC. Functionally, LINC01224 promoted proliferation and inhibited apoptosis of EC cells; LINC01224 directly bound to and downregulated miR-485-5p to elevate the expression levels of AKT3, thereby promoting EC progression. LINC01224 depletion in EC cells hindered tumor growth in a xenograft model. The tumor suppressing effect of LINC01224-knockdown on EC progression was partly rescued by treatment with miR-485-5p inhibitor. The present data demonstrated the expression levels, clinical relevance and functional mechanism of LINC01224 in EC. LINC01224 promoted EC development via sponging miR-485-5p to elevate AKT3 expression levels; this may provide a promising therapeutic target pathway for EC treatment.

Molecular Oncology of Gynecologic Tumors

Oncologists and pathologists alike have recognized that the broad histologic categories, especially for ovarian and endometrial carcinomas, do not reliably segregate groups with similar clinical courses or responses to therapeutic interventions. During the last decade a paradigm shift was invoked when the results from The Cancer Genome Atlas (TCGA) project were published. Comprehensive genomic profiling data from TCGA has shown that there are four molecular subgroups of endometrioid carcinomas instead of the two subtypes proposed by Bokhman in the 1970s. For ovarian carcinomas (OC) it is now evident that molecular parameters are also significant. Although traditionally referred to as a single entity, OC is not a homogeneous disease but rather a group of diseases, each with different morphology and biologic behavior. Similar to endometrial cancers, advanced cervical cancer and recurrent disease remain particularly problematic due to chemotherapy resistance. Effective prophylactic vaccines against the most important carcinogenic human papillomaviruses (HPV) types are available, but uptake remains poor. The E6 and E7 oncoproteins are attractive targets for cancer therapy. They are constitutively expressed in HPV-positive tumors, specific to the tumor, functionally important to the tumor cells and recognized by the adaptive immune system as tumor antigens. This review summarizes recent advances in the molecular pathology, which have greatly improved our understanding of the biology of gynecologic cancers.

Correlation between single nucleotide polymorphisms of DACH1 gene microRNA binding site and susceptibility of patients with endometrial cancer

OBJECTIVE

To study the relationship between single nucleotide polymorphism (SNP) of the 3 primer untranslated region (UTR) variants of the cell fate determination factor Dachshund 1(DACH1) gene and the susceptibility of patients with endometrial cancer (EC).

METHODS

Genomic DNA was extracted from the peripheral venous blood of 235 EC patients and 235 healthy controls, and the DACH1 gene rs9285274, rs9529895, rs17088351, and rs59352399 loci were analyzed by Sanger sequencing. Patients progression-free survival (PFS) was recorded after 3 years follow-up from October 2016 to October 2019.

RESULTS

Carriers of the C allele of the DACH1 gene rs9529895 locus had a significantly lower risk for EC than T allele carriers (odds ratio = 0.56, 95%confidence interval: 0.38-0.84, P < .01). The correlation between DACH1 gene rs9529895 locus SNP and the risk for EC was affected by age, body mass index, smoking, drinking, and diabetes. Age, and rs9285274, rs9529895, and rs59352399 locus SNP were the best models for predicting the risk for EC. The accuracy rate was 57.02%, and the Cross-validation Consistency was 10/10 (x = 4.33, P = .04). The DACH1 gene rs9529895 locus C allele (TC+CC) carriers had significantly higher PFS than the TT genotype carriers (P = .04). The DACH1 gene was expressed in decreased amounts in the cancer tissues of EC patients, and the DACH1 mRNA expression level in the CC genotype, TC genotype, and TT genotype of rs9529895 locus was also decreased (P = .02).

CONCLUSION

DACH1 gene rs9529895 locus SNP is significantly related to the risk for EC and PFS of EC patients. The possible mechanism behind this relationship is that the DACH1 gene rs9529895 locus SNP affects DACH1 expression level.

The role of biomarkers in endometrial cancer and hyperplasia: a literature review

INTRODUCTION

Endometrial cancer is the most common gynaecological cancer and its incidence is rising due to increasing obesity rates. We are also seeing an increasing trend of young women diagnosed with either endometrial cancer or its precancerous state, endometrial hyperplasia. Diagnosis is dependent on invasive testing and there is no screening tool available for either general or high-risk population groups. Whilst vast amounts of research have been undertaken in higher-profile cancers such as ovarian and cervical, endometrial cancer is comparatively less investigated.

AIM

In this literature review, we summarise the existing literature in understanding the role of tumour biomarkers for endometrial cancer and its preceding condition of endometrial hyperplasia.

METHOD

NICE Healthcare Databases Search tool was used to search Embase, Medline and PubMed databases for relevant articles.

CONCLUSION

There is currently no routinely used biomarker in endometrial cancer for diagnostic or prognostic purposes. Given the establishment of new genomic classifications of endometrial cancers, the use of biomarkers to drive therapeutic approaches will be the cornerstone for individualised cancer care in the coming decades.

miR-148b Functions as a Tumor Suppressor by Targeting Endoplasmic Reticulum Metallo Protease 1 in Human Endometrial Cancer Cells

This study investigated the tumor-suppressive role of miR-148b in regulating endoplasmic reticulum metalloprotease 1 (ERMP1) expression and the oxidative stress response in endometrial cancer cells. Human endometrial cancer RL95-2 cells were used and transfected with miR-148b mimic, miR-148b inhibitor, or their scrambled negative control. Thereafter, the transfection efficiency was determined by RT-qPCR, and cell proliferation was assessed by MTT assay. The dual-luciferase reporter assay, Western blot, and RT-qPCR were conducted to determine the target gene of miR-148b. ERMP1 is a putative target of miR-148b, and thereby the overexpression and downregulation of ERMP1 on the proliferation of RL95-2 cells were assessed. Next, the expressions of hypoxia-inducible factor 1 (HIF-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) were analyzed by Western blot. Intracellular reactive oxygen species (ROS) was determined using dichlorofluorescin diacetate (DCFDA). Results showed that differential expression of miR-148b or ERMP1 was observed in normal endometrial tissues and endometrial cancerous tissues. Enhanced expression of miR-148b effectively inhibited proliferation of RL95-2 cells. ERMP1 was the target of miR-148b. ERMP1 silencing obviously suppressed proliferation of RL95-2 cells. Thus, miR-148b repressed cell proliferation, likely through downregulating ERMP1. Furthermore, it was observed that miR-148b significantly decreased expression of HIF-1 and Nrf2 by downregulating ERMP1. The intracellular ROS level was enhanced by miR-148b via downregulating ERMP1. To conclude, our results suggested that miR-148b suppressed cell proliferation and regulated the oxidative stress response in human endometrial cancer RL95-2 cells by inhibiting ERMP1.

LAT1 is a putative therapeutic target in endometrioid endometrial carcinoma

l-type amino acid transporters (LAT1-4) are expressed in various cancer types and are involved in the uptake of essential amino acids such as leucine. Here we investigated the expression of LAT1-4 in endometrial adenocarcinoma and evaluated the contribution of LATs to endometrial cancer cell growth. Analysis of human gene expression data showed that all four LAT family members are expressed in endometrial adenocarcinomas. LAT1 was the most highly expressed, and showed a significant increase in both serous and endometrioid subtypes compared to normal endometrium. Endometrioid patients with the highest LAT1 levels exhibited the lowest disease-free survival. The pan-LAT inhibitor BCH led to a significant decrease in cell growth and spheroid area in four endometrial cancer cell lines tested in vitro. Knockdown of LAT1 by shRNA inhibited cell growth in HEC1A and Ishikawa cells, as well as inhibiting spheroid area in HEC1A cells. These data show that LAT1 plays an important role in regulating the uptake of essential amino acids such as leucine into endometrial cancer cells. Increased ability of BCH compared to LAT1 shRNA at inhibiting Ishikawa spheroid area suggests that other LAT family members may also contribute to cell growth. LAT1 inhibition may offer an effective therapeutic strategy in endometrial cancer patients whose tumours exhibit high LAT1 expression.

Hepatitis C virus core protein modulates pRb2/p130 expression in human hepatocellular carcinoma cell lines through promoter methylation

Background

Hepatitis C Virus (HCV) infection is associated with chronically evolving disease and development of hepatocellular carcinoma (HCC), albeit the mechanism of HCC induction by HCV is still controversial. The nucleocapsid (core) protein of HCV has been shown to be directly implicated in cellular transformation and immortalization, enhancing the effect of oncogenes and decreasing the one of tumor suppressor genes, as RB1 and its protein product pRB. With the aim of identifying novel molecular mechanisms of hepatocyte transformation by HCV, we examined the effect of HCV core protein on the expression of the whole Retinoblastoma (RB) family of tumor and growth suppressor factors, i.e. pRb, p107 and pRb2/p130.

Methods

We used a model system consisting of the HuH-7, HCV-free, human hepatocellular carcinoma cell line and of the HuH-7-CORE cells derived from the former and constitutively expressing the HCV core protein. We determined pRb, p107 and pRb2/p130 protein and mRNA amount of the respective genes RB1, RBL1 and RBL2, RBL2 promoter activity and methylation as well as DNA methyltransferase 1 (DNMT1) and 3b (DNMT3b) expression level. The effect of pRb2/p130 over-expression on the HCV core-expressing HuH-7-CORE cells was also evaluated.

Results

We found that the HCV core protein expression down-regulated pRb2/p130 protein and mRNA levels in HuH-7-CORE cells by inducing promoter hyper-methylation with the concomitant up-regulation of DNMT1 and DNMT3b expression. When pRb2/p130 expression was artificially re-established in HuH-7-CORE cells, cell cycle analysis outlined an accumulation in the G0/G1 phase, as expected.

Conclusions

HCV core appears indeed able to significantly down-regulate the expression and the function of two out of three RB family tumor and growth suppressor factors, i.e. pRb and pRb2/p130. The functional consequences at the level of cell cycle regulation, and possibly of more complex cell homeostatic processes, may represent a plausible molecular mechanism involved in liver transformation by HCV.

Participation of WNT and β-Catenin in Physiological and Pathological Endometrial Changes: Association with Angiogenesis

WNT proteins are involved in embryonic development, sex determination, stem cell recruitment, angiogenesis, and cancer. They take part in morphological changes in the endometrium during development, regulate processes of endometrial proliferation and differentiation. This review presents current knowledge about implication of WNT proteins and β-catenin in physiological endometrial functions as well as their involvement in uterine carcinogenesis. Influence of WNT proteins on the formation of blood vessel, taking place both under healthy and pathological conditions, is also considered. Participation of WNT proteins, β-catenin, and inhibitors and inducers of WNT signaling in the process of endometrial angiogenesis is largely unknown. Thus, confirmation of their local and systemic participation in the process of endometrial angiogenesis may in the long term help to establish new diagnostic and therapeutic approaches in conditions associated with the pathology of the female reproductive system.

Endoplasmic reticulum stress in endometrial cancer

Endometrial cancer (EC) is a common gynecologic malignancy often diagnosed at early stage. In spite of a huge advance in our understanding of EC biology, therapeutic modalities do not have significantly changed over the past 40 years. A restricted number of genes have been reported to be mutated in EC, mediating cell proliferation and invasiveness. However, besides these alterations, few other groups and ourselves recently identified the activation of the unfolded protein response (UPR) and GRP78 increase following endoplasmic reticulum (ER) stress as mechanisms favoring growth and invasion of EC cells. Here, a concise update on currently available data in the field is presented, analyzing the crosstalk between the UPR and the main signaling pathways regulating EC cell proliferation and survival. It is evident that this is a rapidly expanding and promising issue. However, more data are very likely to yield a better understanding on the mechanisms through which EC cells can survive the low oxygen and glucose tumor microenvironment. In this perspective, the UPR and, particularly, GRP78 might constitute a novel target for the treatment of EC in combination with traditional adjuvant therapy.