PTEN methylation is associated with advanced stage and microsatellite instability in endometrial carcinoma

SIM2: Its Prognostic Significance and Oncogenic Role in Endometrial Carcinoma

Background

Endometrial carcinoma ranks as the second most widespread malignancy affecting the reproductive system in females. Effective prognostic biomarkers are required to further improve survival rates for patients. Single-minded homolog 2 (SIM2) is known to participate in neurogenesis as a transcription factor. However, the potential role of SIM2 in endometrial carcinoma remains elusive.

Methods

Multiple public databases, including TIMER2.0, GEIPA2, UALCAN, LinkedOmics, BioGRID, DAVID and cBioPortal, were used to investigate SIM2 mRNA expression, SIM2-associated genes, PPI network, functional enrichment analysis, SIM2 gene alterations and methylation. The association between SIM2 expression and immune cell infiltrates was explored using GSVA. The effects of gene alterations and methylation on patient survival and CD8+T infiltration were examined using GSCA. Moreover, the prognostic potential of SIM2 was evaluated using COX regression, ROC curves and a nomogram model. Finally, the differential expression and function of SIM2 in UCEC were explored using qPCR, WB, CCK8 and Transwell assays.

Results

Our findings revealed the heightened expression of SIM2 in endometrial carcinoma, and that its DNA methylation and CNV alterations were correlated with immune infiltration and patients' prognosis. Additionally, functional enrichment revealed the involvement of SIM2 in transcription regulation and signal transduction. Moreover, we performed cell-based experiments to corroborate the oncogenic function of SIM2 in facilitating cell proliferation, migration and invasion.

Conclusion

Collectively, these results suggest that SIM2 holds promise as both a potential prognostic indicator and a viable treatment target for endometrial carcinoma.

Epigenetic regulation in lung cancer

Lung cancer is indeed a major cause of cancer-related deaths worldwide. The development of tumors involves a complex interplay of genetic, epigenetic, and environmental factors. Epigenetic mechanisms, including DNA methylation (DNAm), histone modifications, and microRNA expression, play a crucial role in this process. Changes in DNAm patterns can lead to the silencing of important genes involved in cellular functions, contributing to the development and progression of lung cancer. MicroRNAs and exosomes have also emerged as reliable biomarkers for lung cancer. They can provide valuable information about early diagnosis and treatment assessment. In particular, abnormal hypermethylation of gene promoters and its effects on tumorigenesis, as well as its roles in the Wnt signaling pathway, have been extensively studied. Epigenetic drugs have shown promise in the treatment of lung cancer. These drugs target the aberrant epigenetic modifications that are involved in the development and progression of the disease. Several factors have been identified as drug targets in non-small cell lung cancer. Recently, combination therapy has been discussed as a successful strategy for overcoming drug resistance. Overall, understanding the role of epigenetic mechanisms and their targeting through drugs is an important area of research in lung cancer treatment.

Comparison of immunohistochemistry and next-generation sequencing results in oncogenic PTEN missense mutations

BACKGROUND

Phosphatase and tensin homolog (PTEN) is one of the most frequently mutated tumor suppressor genes in malignant tumors. Oncogenic PTEN mutations have diagnostic, prognostic, and therapeutic implications. Similar to TP53 mutations, oncogenic PTEN mutations can result from nonsynonymous missense mutations. However, there has been no detailed study on the immunostaining pattern of oncogenic PTEN missense mutations.

METHODS

We retrospectively selected 18 cancers (13 endometrial cancers, 2 brain tumors, 1 ovarian cancer, 1 lung cancer, and 1 cancer of unknown origin) harboring oncogenic PTEN missense mutations, which were confirmed by targeted next-generation sequencing. PTEN immunohistochemistry was conducted for all cases, and the results were compared with sequencing results.

RESULTS

The immunostaining results of PTEN missense mutations revealed a diverse pattern depending on the site of mutation and co-occurring mutation. The most frequent oncogenic PTEN mutations were R130G (4/18, 22.2 %) and R130Q (3/18, 16.7 %). Eleven cases harbored PTEN missense mutations only, whereas the remaining seven cases harbored PTEN truncating mutations and PTEN missense mutations. Complete loss of cytoplasmic expression were found in five cases, of which three had missense mutation only. PTEN R130 residue mutation alone did not showed altered PTEN immunostaining pattern in this study.

CONCLUSIONS

PTEN missense mutation, which comprises a portion of oncogenic PTEN mutation, can manifest as a diverse immunostaining pattern. Complementary testing using both immunostaining and next-generation sequencing should be conducted to accurately evaluate the PTEN status in malignancy.

PTEN, PTENP1, microRNAs, and ceRNA Networks: Precision Targeting in Cancer Therapeutics

The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a well characterised tumour suppressor, playing a critical role in the maintenance of fundamental cellular processes including cell proliferation, migration, metabolism, and survival. Subtle decreases in cellular levels of PTEN result in the development and progression of cancer, hence there is tight regulation of the expression, activity, and cellular half-life of PTEN at the transcriptional, post-transcriptional, and post-translational levels. PTENP1, the processed pseudogene of PTEN, is an important transcriptional and post-transcriptional regulator of PTEN. PTENP1 expression produces sense and antisense transcripts modulating PTEN expression, in conjunction with miRNAs. Due to the high sequence similarity between PTEN and the PTENP1 sense transcript, the transcripts possess common miRNA binding sites with the potential for PTENP1 to compete for the binding, or 'sponging', of miRNAs that would otherwise target the PTEN transcript. PTENP1 therefore acts as a competitive endogenous RNA (ceRNA), competing with PTEN for the binding of specific miRNAs to alter the abundance of PTEN. Transcription from the antisense strand produces two functionally independent isoforms (PTENP1-AS-α and PTENP1-AS-β), which can regulate PTEN transcription. In this review, we provide an overview of the post-transcriptional regulation of PTEN through interaction with its pseudogene, the cellular miRNA milieu and operation of the ceRNA network. Furthermore, its importance in maintaining cellular integrity and how disruption of this PTEN-miRNA-PTENP1 axis may lead to cancer but also provide novel therapeutic opportunities, is discussed. Precision targeting of PTENP1-miRNA mediated regulation of PTEN may present as a viable alternative therapy.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Symphony in the crowd: Key genetic alterations in prostate cancer

Androgen receptor (AR) signaling have been frequently targeted for treating prostate cancer (PCa). Even though primarily patients receive a good therapeutic outcome by targeting AR signaling axis, eventually it emerges resistance by altering the genetic makeup of prostate cells. However, to develop an effective therapeutic regime, it is essential to recognize key genetic alterations in PCa. The most common genetic alterations that give rise to distinct androgen different differentiation states are gene fusion of TMPRSS2 with ETS family genes, deletion, or mutation of tumor suppressor PTEN and TP53 gene, amplification or splicing of AR, altered DNA repair genes. In this review, we describe key genes and genetic changes that have been recognized to contribute to altered prostate environment.

CRISPR-Cas System: The Current and Emerging Translational Landscape

CRISPR-Cas technology has rapidly changed life science research and human medicine. The ability to add, remove, or edit human DNA sequences has transformative potential for treating congenital and acquired human diseases. The timely maturation of the cell and gene therapy ecosystem and its seamless integration with CRISPR-Cas technologies has enabled the development of therapies that could potentially cure not only monogenic diseases such as sickle cell anemia and muscular dystrophy, but also complex heterogenous diseases such as cancer and diabetes. Here, we review the current landscape of clinical trials involving the use of various CRISPR-Cas systems as therapeutics for human diseases, discuss challenges, and explore new CRISPR-Cas-based tools such as base editing, prime editing, CRISPR-based transcriptional regulation, CRISPR-based epigenome editing, and RNA editing, each promising new functionality and broadening therapeutic potential. Finally, we discuss how the CRISPR-Cas system is being used to understand the biology of human diseases through the generation of large animal disease models used for preclinical testing of emerging therapeutics.

Integrated analysis of genome-wide gene expression and DNA methylation profiles reveals candidate genes in ovary endometriosis

BACKGROUND

The incidence of endometriosis (EMs), a common disease in gynecology, has increased over the years. Women suffer from the symptoms caused by EMs, such as chronic pelvic pain, dysmenorrhea, and infertility. However, the etiology and pathophysiology of EMs remain unclear. This study aimed to identify candidate genes of endometriosis through integrated analysis of genome-wide gene expression and DNA methylation profiles.

RESULTS

Eutopic and ectopic endometrial tissues were collected from patients who were diagnosed as ovarian EMs. Genome-wide methylation profiling identified 17551 differentially methylated loci, with 9777 hypermethylated and 7774 hypomethylated loci. Differentially methylated loci were mainly concentrated in the gene body and intergenic regions. Genome-wide gene expression profiling identified 1837 differentially expressed genes (DEGs), with 1079 genes upregulated and 758 downregulated in ectopic groups. Integrated analysis revealed that DNA methylation was negatively correlated to gene expression in most genomic regions, such as exon, 3'UTR, 5'UTR, and promoter. We also identified promoter-related (53 downregulated and 113 upregulated) and enhancer-related DMGs (212 downregulated and 232 upregulated), which were significantly correlated to the gene expression. Further validation of the top-ranked genes belonging to differentially methylated genes (DMGs) and DEGs revealed that TMEM184A, GREM2, SFN, KIR3DX1, HPGD, ESR1, BST2, PIK3CG and RNASE1 were significant candidate genes in ovarian endometriosis.

CONCLUSION

Our study revealed the significance of DNA methylation in the gene expression in ovary endometriosis, which provides new insights and a molecular foundation for understanding the underlying mechanisms of endometriosis.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

PTEN Dual Lipid- and Protein-Phosphatase Function in Tumor Progression

Simple Summary

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a multifunctional tumor suppressor with protein- and lipid-phosphatase activities. The inactivation of PTEN is commonly found in all human cancers and is correlated with tumor progression. PTEN-lipid-phosphatase activity has been well documented to dephosphorylate phosphatidylinositol-3, 4, 5-phosphate (PIP3), which hinders cell growth and survival by dampening the PI3K and AKT signaling activity. PTEN-protein-phosphatase activity is less well studied and understood. Recent studies have reported that PTEN-protein-phosphatase activity dephosphorylates the different proteins and acts in various cell functions. We here review the PTEN mutations and protein-phosphatase substrates in tumor progression. We aim to address the gap in our understanding as to how PTEN protein phosphatase contributes to its tumor-suppression functions.

Abstract

PTEN is the second most highly mutated tumor suppressor in cancer, following only p53. The PTEN protein functions as a phosphatase with lipid- and protein-phosphatase activity. PTEN-lipid-phosphatase activity dephosphorylates PIP3 to form PIP2, and it then antagonizes PI3K and blocks the activation of AKT, while its protein-phosphatase activity dephosphorylates different protein substrates and plays various roles in tumorigenesis. Here, we review the PTEN mutations and protein-phosphatase substrates in tumorigenesis and metastasis. Our purpose is to clarify how PTEN protein phosphatase contributes to its tumor-suppressive functions through PI3K-independent activities.

Research Progress of DNA Methylation in Endometrial Cancer

Endometrial cancer (EC)) is one of the most common malignant tumors of the female genital system, with an increasing incidence and mortality, worldwide. Although the therapeutic strategy of EC is still complicated and challenging, further understanding of carcinogenesis from a gene perspective would allow an effort to improve therapeutic precision in this complex malignancy. DNA methylation is the most widely studied epigenetic alteration in human tumors. Aberrant DNA methylation events, resulting in altered gene expression, are features of many tumor types. In this review, we provide an update on evidence about the roles of aberrant DNA methylation within some classical tumor suppressor genes and oncogenes in endometrial carcinogenesis, and report on recent advances in the understanding of the contribution of aberrant DNA methylation to EC, as well as opportunities and challenges of DNA methylation in EC management and prevention.

MicroRNA 182, 183, 200a, and 200b exhibit strong correlations but no involvement in PTEN protein regulation in uterine endometrial carcinoma

OBJECTIVE

In this study, we focused on five microRNAs (miRNAs) that have been reported to regulate phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene expression, namely miR-182, miR-183, miR-200a, miR-200b, and miR-205, and examined their relationships with PTEN protein expression in endometrial cancer tissues.

METHODS

By utilizing paraffin-embedded blocks of normal endometrium (NE) and endometrial carcinoma (EC) tissue (40 cases each), we measured the expression of miRNAs by real-time PCR. Conversely, we examined PTEN protein expression by immunohistochemistry and computer-assisted image analysis.

RESULTS

The expression of all five miRNAs was significantly higher in the EC group than in the NE group (all P ≤ 0.0001). There was no inverse correlation between PTEN positivity in glandular and/or stromal areas and the expression of the five miRNAs in both groups. Conversely, miR-182, miR-183, miR-200a, and miR-200b displayed similar expression patterns in the EC group, whereas miR-205 displayed moderate correlations with the other four miRNAs.

CONCLUSION

Using endometrial cancer tissues, we found for the first time that miR-182, miR-183, miR-200a, and miR-200b were strongly correlated with each other, whereas miR-205 was not strongly correlated with the other four miRNAs. In addition, the five miRNAs examined in this study only had weak effects on PTEN protein expression based on the lack of clear inverse correlations.

Sclerosing Polycystic Adenoma: Conclusive Clinical and Molecular Evidence of Its Neoplastic Nature

Sclerosing polycystic adenosis, initially considered a non-neoplastic salivary gland lesion and classified as such in the 2017 WHO Classification of Head and Neck Tumors, has been the subject of controversy regarding its possible neoplastic nature. The reporting of recurrent PI3K pathway alteration represents evidence to support these lesions as being neoplastic and more appropriately referred to as sclerosing polycystic adenoma (SPA). Herein, we provide additional evidence that supports the classification of SPA as a true neoplasm. Eight cases of SPA were identified in our database and consultation files. All cases were subjected to PTEN immunohistochemistry (IHC) and next-generation sequencing (NGS). In addition, one patient underwent genetic counseling and germline testing. The cases included 5 men and 3 women with a mean age of 41 years (range 11-78) and all tumors arose in the parotid gland. One patient had multiple recurrences over a period of 2 years. Morphologically the tumors were circumscribed and characterized by an admixture of acini, ducts and cysts embedded in a fibrotic/sclerotic stroma. The cells lining the ducts and cysts showed variable granular, vacuolated, foamy and apocrine cytoplasmic features, as well as acinar cells contained intracytoplasmic brightly eosinophilic granules. The apocrine intraductal proliferations showed mild to moderate atypia in 6 cases. One case showed overt malignant morphology that ranged from intraductal carcinoma to invasive salivary duct carcinoma. Seven cases tested for PTEN IHC showed loss of nuclear expression in the acinar and ductal cells with retained PTEN expression in the myoepithelial cell and stroma. NGS detected PIK3CA or PIK3R1 genetic alterations in 7 cases, including a novel TFG-PIK3CA fusion. Coexisting PTEN mutations were seen in 4 cases, including in a patient with clinical stigmata of Cowden syndrome and confirmed by germline genetic testing. Our findings herein documented including recurrence of tumor, malignant transformation, high prevalence of PI3K pathway oncogenic alterations and the possible heretofore undescribed association with Cowden syndrome add support to classifying SPA as true neoplasms justifying their designation as adenoma, rather than adenosis.

Immunohistochemistry and Next-generation Sequencing Are Complementary Tests in Identifying PTEN Abnormality in Endometrial Carcinoma Biopsies

PTEN plays a central role in the pathogenesis of endometrial carcinoma. Previous studies reported a high interobserver reproducibility for the interpretation of PTEN immunohistochemistry (IHC). However, PTEN IHC and its interpretation remain challenging during laboratory practice. The purpose of this study was to reevaluate PTEN IHC pattern in direct comparison to next-generation sequencing in identifying PTEN abnormality. IHC and tagged-amplicon next-generation sequencing PTEN sequencing was performed on 182 endometrial carcinoma biopsy/curetting samples from five centers (Barts, Calgary, Cambridge, Leiden, and Vancouver). Sensitivity, specificity and accuracy of PTEN IHC to predict loss of function PTEN mutations were calculated. Abnormalities of PTEN in association with histotype and molecular subtype were assessed. A total of 5 PTEN IHC patterns were recorded: absent, subclonal loss, equivocal, reduced (relative to internal control) and retained. The absence of PTEN IHC has a sensitivity of 75.4% (95% confidence interval: 62.7-85.5%), a specificity of 84.6% (95% confidence interval: 76.2%-90.9%), and accuracy of 81.2% (95% confidence interval: 74.4%-86.9%) in predicting loss of function PTEN mutation. PTEN abnormality by complementary interpretation of both assays was present in 91.9% of endometrial endometrioid carcinoma, grade 1, and significantly higher in endometrial endometrioid carcinomas of all grades compared with endometrial serous carcinoma (80.0% vs. 19.4%, P<0.0001). PTEN abnormalities are common across all molecular subtypes of endometrioid carcinomas. Our data support the use of ancillary PTEN IHC for diagnostic purposes in endometrial neoplasms. However, for clinical trial design complementary testing of both IHC and sequencing of PTEN should be considered to assess the PTEN status in endometrial carcinomas.

Metabolic reprogramming and epigenetic modifications on the path to cancer

Metabolic rewiring and epigenetic remodeling, which are closely linked and reciprocally regulate each other, are among the well-known cancer hallmarks. Recent evidence suggests that many metabolites serve as substrates or cofactors of chromatin-modifying enzymes as a consequence of the translocation or spatial regionalization of enzymes or metabolites. Various metabolic alterations and epigenetic modifications also reportedly drive immune escape or impede immunosurveillance within certain contexts, playing important roles in tumor progression. In this review, we focus on how metabolic reprogramming of tumor cells and immune cells reshapes epigenetic alterations, in particular the acetylation and methylation of histone proteins and DNA. We also discuss other eminent metabolic modifications such as, succinylation, hydroxybutyrylation, and lactylation, and update the current advances in metabolism- and epigenetic modification-based therapeutic prospects in cancer.

Recent insights in the PI3K/Akt pathway as a promising therapeutic target in combination with EGFR-targeting agents to treat head and neck squamous cell carcinoma

Resistance to therapies targeting the epidermal growth factor receptor (EGFR), such as cetuximab, remains a major roadblock in the search for effective therapeutic strategies in head and neck squamous cell carcinoma (HNSCC). Due to its close interaction with the EGFR pathway, redundant or compensatory activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway has been proposed as a major driver of resistance to EGFR inhibitors. Understanding the role of each of the main proteins involved in this pathway is utterly important to develop rational combination strategies able to circumvent resistance. Therefore, the current work reviewed the role of PI3K/Akt pathway proteins, including Ras, PI3K, tumor suppressor phosphatase and tensing homolog, Akt and mammalian target of rapamycin in resistance to anti-EGFR treatment in HNSCC. In addition, we summarize PI3K/Akt pathway inhibitors that are currently under (pre)clinical investigation with focus on overcoming resistance to EGFR inhibitors. In conclusion, genomic alterations in and/or overexpression of one or more of these proteins are common in both human papillomavirus (HPV)-positive and HPV-negative HNSCC tumors. Therefore, downstream effectors of the PI3K/Akt pathway serve as promising drug targets in the search for novel therapeutic strategies that are able to overcome resistance to anti-EGFR treatment. Co-targeting EGFR and the PI3K/Akt pathway can lead to synergistic drug interactions, possibly restoring sensitivity to EGFR inhibitors and hereby improving clinical efficacy. Better understanding of the predictive value of PI3K/Akt pathway alterations is needed to allow the identification of patient populations that might benefit most from these combination strategies.

Alterations of PTEN and SMAD4 methylation in diagnosis of breast cancer: implications of methyl II PCR assay

Background

Diagnosis of breast cancer is more complicated due to lack of minimal invasive biomarker with sufficient precision. DNA methylation is a promising marker for cancer diagnosis. In this study, authors evaluated methylation patterns for PTEN and SMAD4 in blood samples using EpiTect Methyl II QPCR assay quantitative PCR technology.

Results

Methylation status for PTEN and SMAD4 were statistically significant as breast cancer patients reported hypermethylation compared to benign and control groups (77.1 ± 17.9 vs. 24.9 ± 4.5 and 15.1 ± 1.4 and 70.1 ± 14.4 vs. 28.2 ± 0.61 and 29.5 ± 3.6, respectively). ROC curve analysis revealed that both PTEN (AUC = 0.992) and SMAD4 (AUC = 0.853) had good discriminative power for differentiating BC from all non-cancer individuals (benign and healthy combined) compared to routine tumor markers CEA (AUC = 0.538) and CA15.3 (AUC = 0.686). High PTEN methylation degree was associated with late stages (84.2 ± 17.4), positive lymph node (84.2 ± 18.5), positive ER (81.3 ± 19.7), positive PgR (79.5 ± 19.1), and positive HER2 (80.7 ± 19.0) vs. 67.4 ± 13.8, 70.6 ± 14.8, 72.8 ± 14.9, 72.5 ± 14.7, and 70.2 ± 13.5 in early stages, negative lymph node, negative ER, negative PgR, and negative HER2, respectively. Similar results were obtained regarding SMAD4 methylation. Sensitivity, specificity, positive and negative predictive values, and accuracy for methylated PTEN were 100%, 95%, 99.1%, 100%, and 95%, respectively when differentiated BC from all-non cancer controls. Interestingly, PTEN could distinguish early BC stages with good sensitivity 84.4%, 51.4%, 69.1%, 72%, and 70%, respectively.

Conclusion

Methylation status of PTEN and SMAD4 is a promising blood marker for early detection of breast cancer. Future studies are needed for their role as prognostic markers.

CRISPR/Cas9 in epigenetics studies of health and disease

Epigenetics is the heritable phenotypic changes without altering the genotype. Epigenetic processes are such as histone methylation, acetylation, ubiquitination, sumoylation, phosphorylation, ADP ribosylation, DNA methylation and non-coding RNAs interactions associated with structural changes in chromatin. The change of structure is either open chromatin for "active" state or closed chromatin for "inactive" state, that regulates important biological phenomenon like chromatin condensation, gene expression, DNA repair, cellular development, differentiation and homeostasis, etc. However, dysregulation of epigenetic patterns causes diseases like cancer, diabetes, neurological disorder, infectious diseases, autoimmunity etc. Besides, the most important clinical uses of Epigenetics studies are i. identification of disease biomarkers and ii. development of their therapeutics. Epigenetic therapies include epi-drugs, combinatorial therapy, nanocarriers, plant-derived products that are being used for changing the epigenetic pattern to reverse gene expression. However, the developed epi- drugs cause off-target gene and transposable elements activation; promote mutagenesis and carcinogenesis in normal cells, are the major hurdles regarding their clinical use. Therefore, advanced epigenetic therapeutics are required to develop target-specific epigenetic modifications to reverse gene expression pattern. CRISPR-Cas9 (Clustered Regularly Interspaced Palindrome Repeats-associated protein 9) system-mediated gene activation mechanism paves new methods of target-specific epigenetic therapeutics to cure diseases. In this chapter, we discuss how CRISPR/Cas9 and dCas9 have recently been engineered for epigenome editing. Different strategies have been discussed used for epigenome editing based on their efficacy and complexity. Last but not least we have discussed the limitations, different uses of CRISPR/Cas9 and dCas9 in the area of genetic engineering.

ROR2 Is Epigenetically Regulated in Endometrial Cancer

Simple Summary

Endometrial cancer is one of the fastest rising cancers in women. The Wnt signalling receptor ROR2 has been shown to play distinct roles in regards to tumorigenesis in different tumour types. The aim of this study was to investigate the role of ROR2 in endometrial cancer and to determine if ROR2 expression is epigenetically regulated. Through the analyses of publicly available TCGA and GEO datasets, low ROR2 expression was correlated with unfavourable outcome and reduced overall survival of endometrial cancer patients. In addition, we observed epigenetic repression of ROR2 expression in endometrial cancer cell lines and patient samples. Ectopic expression of ROR2 in vitro inhibited the invasive ability of high grade serous endometrial cancer cells. Therefore, we concluded that ROR2 plays a tumour suppressor role in endometrial cancer and appears to be a diagnostic or therapeutic candidate.

Abstract

The Wnt signalling receptor ROR2 has been identified as a possible therapeutic target in numerous cancers; however, its exact role remains unclear. The aim of this study was to investigate the role of ROR2 in endometrial cancer (EC) and the potential mechanism associated with its altered expression. The association between ROR2 mRNA expression levels and clinicopathological parameters, including overall survival (OS), in EC was analysed in The Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (TCGA-UCEC) cohort and GEO dataset GSE17025. Four EC cell lines (KLE, MFE-296, Ishikawa and ARK-1) and eight clinical EC samples were analysed for ROR2 methylation via Combined Bisulphite Restriction Analysis (COBRA) and bisulphite genomic sequencing (BGS). In addition, the functional effects of ROR2 overexpression were investigated in Ishikawa and ARK-1 cells following ectopic ROR2 expression. ROR2 promoter methylation or reduced ROR2 expression were both found to correlate with shorter OS, high grade and serous subtype in the TCGA-UCEC and GEO datasets. ROR2 was epigenetically silenced by promoter methylation in both patient samples and cell lines. A significant correlation between ROR2 expression levels and promoter methylation was observed in patient samples (r = −0.797, p = 0.018). ROR2 restoration in ARK-1 significantly decreased invasion ability, with associated changes in epithelial-mesenchymal transition (EMT) markers. ROR2 plays a tumour-suppressor role in EC and is epigenetically suppressed with the development of disease. It may represent a diagnostic or therapeutic candidate for EC.

High-risk HPV infection modulates the promoter hypermethylation of APC, SFRP1, and PTEN in cervical cancer patients of North India

Persistent infection with oncogenic HPV and downregulation of tumor suppressor genes play an essential role in the development and progression of cervical cancer. The present study aimed to identify the promoter methylation status of APC, SFRP1, and PTEN which are important regulators of Wnt pathway and their association with high-risk HPV infection and gene expression. Methylation Specific PCR (MSP) and quantitative reverse transcription PCR (RT-qPCR) were used to detect methylation status and gene expression levels of APC, SFRP1, and PTEN in cervical cancer biopsies (110) and paired non-cancerous biopsies (28). APC promoter was methylated in 38%, SFRP1 in 95%, and PTEN in 55% of the cervical cancer biopsies. Our data showed a trend of a higher rate of methylation of the gene promoters in cervical cancer biopsies while; they were majorly un-methylated in non-cancerous biopsies. Corresponding to a higher rate of methylation in cancer biopsies, the gene expression levels of APC, SFRP1, and PTEN were reduced in cervical cancer samples in comparison to normal cervix tissues. Further, we observed that 97% cancer biopsies were HPV infected and high-risk type HPV16 and 18 infections were significantly positively associated with APC (p = 0.008 and p = 0.007), SFRP1 (p = 0.003 and p = 0.0067), and PTEN (p = 0.049 and p = 0.008) promoter methylation. APC, SFRP1, and PTEN promoter hyper-methylation is positively associated with high-risk HPV infection and inversely associated with gene expression. Our findings show that high-risk HPV infection promotes methylation of these genes and further promotes their silencing.

Androgen receptor and uterine histoarchitecture in a PCOS rat model

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenemia and uterine abnormalities. Our aim was to investigate the uterine effects of PCOS that are mediated through the androgen receptor (AR). After weaning, female rats were treated with sesame oil (Control), dehydroepiandrosterone (DHEA), or DHEA + flutamide (FLU, an AR antagonist) for 20 consecutive days. On postnatal day 41, serum, ovarian and uterine tissues were collected. DHEA and DHEA + FLU rats showed increased testosterone levels. DHEA rats showed increased epithelial height, glandular density, subepithelial stroma and myometrial thickness, associated with decreased nuclei density. These rats also showed increased uterine water content, with decreased aquaporin (AQP) 3, 7 and 8 expression in the uterine epithelium and increased AQP8 expression in the myometrium. DHEA rats also showed decreased uterine collagen remodeling, decreased cell proliferation in the subepithelial stroma, and increased apoptosis in the luminal and glandular epithelium and in the myometrium. They also showed an increase in insulin-like growth factor-1 and a decrease in phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase. The uterine stroma of DHEA rats showed no changes in progesterone receptor or estrogen receptor alpha (ERα) and increased AR expression. DHEA + FLU rats showed a smaller increase in the myometrial thickness, an increase in the uterine water content without AQP8 induction and a smaller decrease in collagen remodeling. These rats also showed no apoptosis induction and decreased proliferation in the myometrium, decreased ERα in the subepithelial stroma and myometrium and no modifications in AR. Our results demonstrate that the uterine cell turnover and collagen remodeling in DHEA rats are regulated through AR, directly or indirectly associated with ERα expression.

Role of Ubiquitination in PTEN Cellular Homeostasis and Its Implications in GB Drug Resistance

Glioblastoma (GB) is the most common and aggressive brain malignancy, characterized by heterogeneity and drug resistance. PTEN, a crucial tumor suppressor, exhibits phosphatase-dependent (PI3K-AKT-mTOR pathway)/independent (nucleus stability) activities to maintain the homeostatic regulation of numerous physiological processes. Premature and absolute loss of PTEN activity usually tends to cellular senescence. However, monoallelic loss of PTEN is frequently observed at tumor inception, and absolute loss of PTEN activity also occurs at the late stage of gliomagenesis. Consequently, aberrant PTEN homeostasis, mainly regulated at the post-translational level, renders cells susceptible to tumorigenesis and drug resistance. Ubiquitination-mediated degradation or deregulated intracellular localization of PTEN hijacks cell growth rheostat control for neoplastic remodeling. Functional inactivation of PTEN mediated by the overexpression of ubiquitin ligases (E3s) renders GB cells adaptive to PTEN loss, which confers resistance to EGFR tyrosine kinase inhibitors and immunotherapies. In this review, we discuss how glioma cells develop oncogenic addiction to the E3s-PTEN axis, promoting their growth and proliferation. Antitumor strategies involving PTEN-targeting E3 ligase inhibitors can restore the tumor-suppressive environment. E3 inhibitors collectively reactivate PTEN and may represent next-generation treatment against deadly malignancies such as GB.

Discriminating miRNA Profiles between Endometrioid Well- and Poorly-Differentiated Tumours and Endometrioid and Serous Subtypes of Endometrial Cancers

The discrimination of different subtypes of endometrial carcinoma (EC) is frequently problematic when using the current histomorphological classification; therefore, new markers for this differentiation are needed. Here, we examined differences in miRNA expression between well- and poorly-differentiated (grades 1 and 3) endometrioid endometrial carcinoma (EEC) and between EEC and serous endometrial carcinoma (SEC). The expression of 84 tumour-suppressor miRNAs was analysed by real-time polymerase chain reactions in 62 EC and 20 non-neoplastic endometrial specimens. The potential functions of the differentially expressed miRNAs were determined by bioinformatics analyses. The expression of let-7c-5p, miR-125b-5p, miR-23b-3p, and miR-99a-5p in grade 3 EEC was decreased compared to grade 1 EEC. To discriminate between EEC and SEC, let-7g-5p, miR-195-5p, miR-34a-5p, and miR-497-5p expression was significantly downregulated in SEC. In bioinformatic analyses, miRNAs that could discriminate grade 1 from grade 3 mainly targeted genes involved in PI3K-AKT signaling, whereas miRNAs that could discriminate EEC from SEC targeted genes involved in several signaling pathways, but mainly MAPK signaling. Taken collectively, our results indicate that the activation of certain signaling pathways can be useful in the molecular characterization of EEC and SEC.

Hepatic Stellate Cells and Hepatocarcinogenesis

Hepatic stellate cells (HSCs) are a significant component of the hepatocellular carcinoma (HCC) tumor microenvironment (TME). Activated HSCs transform into myofibroblast-like cells to promote fibrosis in response to liver injury or chronic inflammation, leading to cirrhosis and HCC. The hepatic TME is comprised of cellular components, including activated HSCs, tumor-associated macrophages, endothelial cells, immune cells, and non-cellular components, such as growth factors, proteolytic enzymes and their inhibitors, and other extracellular matrix (ECM) proteins. Interactions between HCC cells and their microenvironment have become topics under active investigation. These interactions within the hepatic TME have the potential to drive carcinogenesis and create challenges in generating effective therapies. Current studies reveal potential mechanisms through which activated HSCs drive hepatocarcinogenesis utilizing matricellular proteins and paracrine crosstalk within the TME. Since activated HSCs are primary secretors of ECM proteins during liver injury and inflammation, they help promote fibrogenesis, infiltrate the HCC stroma, and contribute to HCC development. In this review, we examine several recent studies revealing the roles of HSCs and their clinical implications in the development of fibrosis and cirrhosis within the hepatic TME.

PTEN, a Barrier for Proliferation and Metastasis of Gastric Cancer Cells: From Molecular Pathways to Targeting and Regulation

Cancer is one of the life-threatening disorders that, in spite of excellent advances in medicine and technology, there is no effective cure for. Surgery, chemotherapy, and radiotherapy are extensively applied in cancer therapy, but their efficacy in eradication of cancer cells, suppressing metastasis, and improving overall survival of patients is low. This is due to uncontrolled proliferation of cancer cells and their high migratory ability. Finding molecular pathways involved in malignant behavior of cancer cells can pave the road to effective cancer therapy. In the present review, we focus on phosphatase and tensin homolog (PTEN) signaling as a tumor-suppressor molecular pathway in gastric cancer (GC). PTEN inhibits the PI3K/Akt pathway from interfering with the migration and growth of GC cells. Its activation leads to better survival of patients with GC. Different upstream mediators of PTEN in GC have been identified that can regulate PTEN in suppressing growth and invasion of GC cells, such as microRNAs, long non-coding RNAs, and circular RNAs. It seems that antitumor agents enhance the expression of PTEN in overcoming GC. This review focuses on aforementioned topics to provide a new insight into involvement of PTEN and its downstream and upstream mediators in GC. This will direct further studies for evaluation of novel signaling networks and their targeting for suppressing GC progression.

An organoid-based drug screening identified a menin-MLL inhibitor for endometrial cancer through regulating the HIF pathway

Tumor organoids recapitulate pathological properties and would serve as an excellent ex vivo model for drug discovery. Here, we performed an unbiased drug screening on drivers-defined tumor organoids from mouse endometrial cancer, the most prevalent gynecological malignancy in human, with a small molecule library targeting epigenetic factors. Among them, menin-MLL inhibitors MI-136 and MI-463 scored. The therapeutic capacity of MI-136 was further validated in tumor organoids in vitro and an orthotopic model in vivo. CRISPR/cas9-mediated mutations of major components of the menin-MLL complex, Men1, Kmt2a and Ash2l, inhibited the growth of tumor organoids, suggesting that the complex was the target of MI-136. Transcriptome analysis showed that the hypoxia-inducible factor (HIF) pathway was the most significantly downregulated pathway by MI-136 treatment. Consistently, Men1, Kmt2a, and Ash2l knockout also repressed the expressions of the HIF target genes. Loss of Hif1a or Hif1b partially phenocopied the inhibition of the menin-MLL complex by MI-136 or mutations in term of tumor organoid growth. Further, we found that MEN1 was upregulated in human endometrial cancers, which were tightly correlated with the expression levels of HIF1A, and associated with poor prognosis. Importantly, MI-136 also significantly inhibited the growth of endometrial cancer organoids derived from patients. Thus, our study identified MI-136 as a potential inhibitor for endometrial cancer through regulating the HIF pathway, a novel molecular mechanism distinguished from those in AML and prostate cancer.

Improving response to progestin treatment of low-grade endometrial cancer

OBJECTIVES

This review examines how response rates to progestin treatment of low-grade endometrial cancer can be improved. In addition to providing a brief overview of the pathogenesis of low-grade endometrial cancer, we discuss limitations in the current classification of endometrial cancer and how stratification may be refined using molecular markers to reproducibly identify 'low-risk' cancers which may represent the best candidates for progestin therapy. We also discuss constraints in current approaches to progestin treatment of low-grade endometrial cancer and perform a systematic review of predictive biomarkers.

METHODS

PubMed, ClinicalTrials.gov, and Cochrane Library were searched for studies reporting pre-treatment biomarkers associated with outcome in women with low-grade endometrial cancer or endometrial hyperplasia with an intact uterus who received progestin treatment. Studies of fewer than 50 women were excluded. The study protocol was registered in PROSPERO (ID 152374). A descriptive synthesis of pre-treatment predictive biomarkers reported in the included studies was conducted.

RESULTS

Of 1908 records reviewed, 19 studies were included. Clinical features such as age or body mass index cannot predict progestin response. Lesions defined as 'low-risk' by FIGO criteria (stage 1A, grade 1) can respond well; however, the reproducibility and prognostic ability of the current histopathological classification system is suboptimal. Molecular markers can be reproducibly assessed, have been validated as prognostic biomarkers, and may inform patient selection for progestin treatment. DNA polymerase epsilon (POLE)-ultramutated tumors and a subset of p53 wild-type or DNA mismatch repair (MMR)-deficient tumors with 'low-risk' features (eg, progesterone and estrogen receptor-positive) may have improved response rates, though this needs to be validated.

DISCUSSION

Molecular markers can identify cases which may be candidates for progestin treatment. More work is needed to validate these biomarkers and potentially identify new ones. Predictive biomarkers are anticipated to inform future research into progestin treatment of low-grade endometrial cancer and ultimately improve patient outcomes.

Feasibility of endometrial sampling by vaginal tampons in women with Lynch syndrome

Background

Endometrial sampling for the surveillance of women with Lynch syndrome is an invasive and painful procedure. The aim of this study was to evaluate the feasibility of a less invasive procedure of collecting vital cells by vaginal tampons.

Methods

This was a prospective feasibility study of women scheduled to undergo annual gynecological surveillance, including endometrial sampling. We included consecutive asymptomatic women with Lynch syndrome or first-degree relatives and asked them to insert a vaginal tampon 2–4 h before attending their outpatient appointment. Feasibility was evaluated by the following metrics: patient acceptance, pain intensity of each procedure (assessed by visual analog scale; range 0–10), and the presence of vital cells obtained by tampon-based or endometrial sampling methods. Two pathologists independently evaluated all samples.

Results

In total, 25 of 32 approached women completed the tampon-based procedure, with 23 of these subsequently undergoing invasive endometrial sampling. The median visual analog scale scores for tampon use and invasive endometrial sampling were 0 (range, 0–10) and 5.5 (range, 1–10) (p < 0.001). None of the tampon samples analyzed by cytology showed endometrial cells, but they did contain vital squamous cells and granulocytes. By contrast, 18 (78%) of the invasive endometrial samples contained enough endometrial tissue for analysis. No endometrial abnormalities were found by endometrial sampling.

Conclusions

Tampon-based endometrial surveillance was a well-accepted and non-painful procedure, and although tampons contained vital cells, they did not provide endometrial cells. However, this study was limited to asymptomatic women with Lynch syndrome (no endometrial pathology), indicating that research is needed to evaluate whether the tampon method has any utility for endometrial surveillance in women with Lynch syndrome.

Knockdown of lncRNA TDRG1 Inhibits Tumorigenesis in Endometrial Carcinoma Through the PI3K/AKT/mTOR Pathway

BACKGROUND AND OBJECTIVE

Endometrial carcinoma (EC) is one of the most frequently diagnosed malignancies in females. Dysregulation of lncRNA TDRG1 has been widely documented in several cancers, including EC. However, the mechanism of this lncRNA involving in EC progression remains to be further elucidated.

MATERIALS AND METHODS

The enrichment levels of TDRG1 in EC tissues and cell lines were examined by RT-qPCR. Flow cytometry, cell counting kit-8 (CCK-8), transwell, and Western blot assays were conducted to assess whether TDRG1 knockdown could affect cell cycle arrest, proliferation, migration, invasion, and apoptosis of EC cells. The phosphorylation levels of mTOR, AKT and PI3K that associated with PI3K/Akt/mTOR pathway were determined by Western blot assay.

RESULTS

TDRG1 expression was markedly upregulated in EC tissues and cell lines. Knockdown of TDRG1 significantly induced cell cycle arrest and apoptosis, inhibited cell proliferation, restrained the invasion and migration abilities in EC cells. Moreover, TDRG1 silencing decreased the protein levels of p-AKT, p-PI3K, and p-mTOR of EC cells.

CONCLUSION

Our data underlined the implication of TDRG1 in EC progression, proposing that targeting TDRG1 might be a potential therapeutic avenue in EC.

PTEN deletion drives aberrations of DNA methylome and transcriptome in different stages of prostate cancer

Phosphatase and tensin homolog located on chromosome 10 (PTEN) is a tumor suppressor gene and one of the most frequently mutated/deleted genes in human prostate cancer (PCa). However, how PTEN deletion would impact the epigenome and transcriptome alterations remain unknown. This hypothesis was tested in a prostate-specific PTEN-/- (KO) mouse prostatic adenocarcinoma model through DNA methyl-Seq and RNA-Seq analyses. Examination of cancer genomic datasets revealed that PTEN is expressed at lower levels in PTEN-deleted tumor samples than in normal solid tissue samples. Methylome and transcriptome profiling identified several inflammatory responses and immune response signaling pathways, including NF-kB signaling, IL-6 signaling, LPS/IL-1-mediated inhibition of RXR Function, PI3K in B lymphocytes, iCOS-iCOSL in T helper cells, and the role of NFAT in regulating the immune response, were affected by PTEN deletion. Importantly, a small subset of genes that showed DNA hypermethylation or hypomethylation was correlated with decreased or increased gene expression including CXCL1. quantitative polymerase chain reaction analyses of representative genes validated the RNA-Seq results. Histopathological examinations showed that the severity of prostatic intraepithelial neoplasia and inflammation development gradually increased as PTEN null mice aged. Collectively, these findings suggest that loss of PTEN drives global changes in DNA CpG methylation and transcriptomic gene expression and highly associated with several inflammatory and immune molecular pathways during PCa development. These biomarkers could be valuable molecular targets for cancer drug discovery and development against PCa.

Multifaceted Regulation of PTEN Subcellular Distributions and Biological Functions

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene frequently found to be inactivated in over 30% of human cancers. PTEN encodes a 54-kDa lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase pathway involved in the promotion of multiple pro-tumorigenic phenotypes. Although the PTEN protein plays a pivotal role in carcinogenesis, cumulative evidence has implicated it as a key signaling molecule in several other diseases as well, such as diabetes, Alzheimer's disease, and autism spectrum disorders. This finding suggests that diverse cell types, especially differentiated cells, express PTEN. At the cellular level, PTEN is widely distributed in all subcellular compartments and organelles. Surprisingly, the cytoplasmic compartment, not the plasma membrane, is the predominant subcellular location of PTEN. More recently, the finding of a secreted 'long' isoform of PTEN and the presence of PTEN in the cell nucleus further revealed unexpected biological functions of this multifaceted molecule. At the regulatory level, PTEN activity, stability, and subcellular distribution are modulated by a fascinating array of post-translational modification events, including phosphorylation, ubiquitination, and sumoylation. Dysregulation of these regulatory mechanisms has been observed in various human diseases. In this review, we provide an up-to-date overview of the knowledge gained in the last decade on how different functional domains of PTEN regulate its biological functions, with special emphasis on its subcellular distribution. This review also highlights the findings of published studies that have reported how mutational alterations in specific PTEN domains can lead to pathogenesis in humans.

The Relationship between the Methylation of Promoter Regions of Tumor Suppressor Genes PTEN and APC with Endometrial Cancer

Background:

Endometrial neoplasms is one of the most typical gynecologic diseases with harmful effects. Promoter hypermethylation is an important mechanism of the inactivation of tumor suppressor genes in endometrial neoplasms. Epigenetic changes of the PTEN and APC genes have shown to be present in various cancers. Therefore, in this study, we have investigated the association between the promoter hypermethylation of PTEN and APC genes with endometrial neoplasms.

Methods:

For this study, 28 patients with endometrial neoplasms as well as 22 controls were studied. Analysis of the promoter methylation regions of PTEN and APC genes were performed by Methylation-Specific PCR.

Results:

The frequency of PTEN and APC genes promoter methylation was 28.57% and 17.86% in tumor tissues, and 11.54% and 3.85% in blood samples, respectively. We found a significant relationship between blood and tissue in PTEN methylation (p = 0.0353). Additionally, we determined a closely significant difference between normal tissue and tumor tissue of the PTEN gene (p = 0.0787) and blood and tissue samples of the APC gene in methylated promoter regions (p=0.0623). Furthermore, these results suggest that there is no significant relationship between the promoter methylation of PTEN and APC with clinical characteristics.

Conclusion:

DNA methylation deficiency is a well known highlighted factor in tumorigenesis, therefore the promoter hypermethylation of PTEN and APC can be indicated as a risk factor in endometrial neoplasms.

PTEN Tumor-Suppressor: The Dam of Stemness in Cancer

PTEN is one of the most frequently inactivated tumor suppressor genes in cancer. Loss or variation in PTEN gene/protein levels is commonly observed in a broad spectrum of human cancers, while germline PTEN mutations cause inherited syndromes that lead to increased risk of tumors. PTEN restrains tumorigenesis through different mechanisms ranging from phosphatase-dependent and independent activities, subcellular localization and protein interaction, modulating a broad array of cellular functions including growth, proliferation, survival, DNA repair, and cell motility. The main target of PTEN phosphatase activity is one of the most significant cell growth and pro-survival signaling pathway in cancer: PI3K/AKT/mTOR. Several shreds of evidence shed light on the critical role of PTEN in normal and cancer stem cells (CSCs) homeostasis, with its loss fostering the CSC compartment in both solid and hematologic malignancies. CSCs are responsible for tumor propagation, metastatic spread, resistance to therapy, and relapse. Thus, understanding how alterations of PTEN levels affect CSC hallmarks could be crucial for the development of successful therapeutic approaches. Here, we discuss the most significant findings on PTEN-mediated control of CSC state. We aim to unravel the role of PTEN in the regulation of key mechanisms specific for CSCs, such as self-renewal, quiescence/cell cycle, Epithelial-to-Mesenchymal-Transition (EMT), with a particular focus on PTEN-based therapy resistance mechanisms and their exploitation for novel therapeutic approaches in cancer treatment.

Metabolic Dysregulations and Epigenetics: A Bidirectional Interplay that Drives Tumor Progression

Cancer has been considered, for a long time, a genetic disease where mutations in keyregulatory genes drive tumor initiation, growth, metastasis, and drug resistance. Instead, theadvent of high-throughput technologies has revolutionized cancer research, allowing to investigatemolecular alterations at multiple levels, including genome, epigenome, transcriptome, proteome,and metabolome and showing the multifaceted aspects of this disease. The multi-omics approachesrevealed an intricate molecular landscape where different cellular functions are interconnected andcooperatively contribute to shaping the malignant phenotype. Recent evidence has brought to lighthow metabolism and epigenetics are highly intertwined, and their aberrant crosstalk can contributeto tumorigenesis. The oncogene-driven metabolic plasticity of tumor cells supports the energeticand anabolic demands of proliferative tumor programs and secondary can alter the epigeneticlandscape via modulating the production and/or the activity of epigenetic metabolites. Conversely,epigenetic mechanisms can regulate the expression of metabolic genes, thereby altering themetabolome, eliciting adaptive responses to rapidly changing environmental conditions, andsustaining malignant cell survival and progression in hostile niches. Thus, cancer cells takeadvantage of the epigenetics-metabolism crosstalk to acquire aggressive traits, promote cellproliferation, metastasis, and pluripotency, and shape tumor microenvironment. Understandingthis bidirectional relationship is crucial to identify potential novel molecular targets for theimplementation of robust anti-cancer therapeutic strategies.

Recent advances in endometrial cancer: a review of key clinical trials from 2015 to 2019

In the past few years, we have seen several important advances in understanding of and therapy for endometrial cancer. This review highlights key recent abstracts and publications in endometrial cancer from 2015 to 2019. We focus on clinical trials in surgical staging and the utility of sentinel lymph node mapping, adjuvant treatment for high-risk disease and HER2/neu-positive serous tumors, combination therapy for recurrent disease, molecular biology, and immunotherapy.

Methylation and PTEN activation in dental pulp mesenchymal stem cells promotes osteogenesis and reduces oncogenesis

Lineage commitment and tumorigenesis, traits distinguishing stem cells, have not been well characterized and compared in mesenchymal stem cells derived from human dental pulp (DP-MSCs) and bone marrow (BM-MSCs). Here, we report DP-MSCs exhibit increased osteogenic potential, possess decreased adipogenic potential, form dentin pulp-like complexes, and are resistant to oncogenic transformation when compared to BM-MSCs. Genome-wide RNA-seq and differential expression analysis reveal differences in adipocyte and osteoblast differentiation pathways, bone marrow neoplasm pathway, and PTEN/PI3K/AKT pathway. Higher PTEN expression in DP-MSCs than in BM-MSCs is responsible for the lineage commitment and tumorigenesis differences in both cells. Additionally, the PTEN promoter in BM-MSCs exhibits higher DNA methylation levels and repressive mark H3K9Me2 enrichment when compared to DP-MSCs, which is mediated by increased DNMT3B and G9a expression, respectively. The study demonstrates how several epigenetic factors broadly affect lineage commitment and tumorigenesis, which should be considered when developing therapeutic uses of stem cells.

Assessment of epigenetic alterations and in silico analysis of mutation affecting PTEN expression among Indian cervical cancer patients

Genetic and epigenetic anomalies accountable for genetic dysregulation are the most common aberrations that determine the underlying heterogeneity of the tumor cells. Currently, phosphatase and tensin homolog (PTEN) incongruity has emerged as potent and persuasive malfunctioning in varied human malignancies. In this study, we have analysed the promoter hypermethylation and expression status of PTEN. We identified different mutations in the exonic region of PTEN. Functional consequences of these mutations were explored using in silico techniques. Promoter hypermethylation of PTEN was detected using methylation-specific polymerase chain reaction (MS-PCR), expression analysis was performed with immunohistochemistry (IHC) and mutation by direct sequencing in a total of 168 uterine cervix tumor cases. The findings were statistically correlated with the clinical parameters. In addition, the effect of nonsynonymous mutations was studied with molecular dynamics simulations. PTEN promoter hypermethylation (45.8%) was found to be significantly associated with the of PTEN loss (57.14%, P < 0.0001). Tumor stages, tumor size, lymph node (LN) were found to be significantly correlated with both PTEN promoter hypermethylation and PTEN loss. Histological grade, however, showed a significant association with only PTEN loss. In total, 11.76% of tumors exhibited mutations in exon 5 and 7, out of which E150K of exon 5 showed the highest deviations in the crystal structure of PTEN by in silico analysis. This study provides valuable insights into oncology and paves the path in the development of efficient biomarker and/or imperative therapeutic tool for cervical cancer treatment.

Two-sided role of estrogen on endometrial carcinogenesis: stimulator or suppressor?

Endometrial carcinoma (EC) often expresses estrogen receptors (ER), and the growth of EC is stimulated by estrogen. Therefore, EC is considered to be an estrogen-dependent tumor. However, the role of estrogen in endometrial carcinogenesis is somewhat unclear because the majority of EC occurs at peri- or post menopause when serum estrogen levels are generally decreased. In this article, we describe the double-edged role of estrogen in the genesis of EC, especially in terms of mismatch repair functions in vitro and in vivo, i.e. when serum estradiol (E2) levels are relatively low (approximately less than 90 pg/ml), and E2 enhance the carcinogenesis, whereas high E2 levels may suppress the carcinogenesis. This will deepen mechanistic insight into unopposed estrogen.

Mechanisms of PTEN loss in cancer: It's all about diversity

PTEN is a phosphatase which metabolises PIP₃, the lipid product of PI 3-Kinase, directly opposing the activation of the oncogenic PI3K/AKT/mTOR signalling network. Accordingly, loss of function of the PTEN tumour suppressor is one of the most common events observed in many types of cancer. Although the mechanisms by which PTEN function is disrupted are diverse, the most frequently observed events are deletion of a single gene copy of PTEN and gene silencing, usually observed in tumours with little or no PTEN protein detectable by immunohistochemistry. Accordingly, with the exceptions of glioblastoma and endometrial cancer, mutations of the PTEN coding sequence are uncommon (<10%) in most types of cancer. Here we review the data relating to PTEN loss in seven common tumour types and discuss mechanisms of PTEN regulation, some of which appear to contribute to reduced PTEN protein levels in cancers.

Activating PTEN Tumor Suppressor Expression with the CRISPR/dCas9 System

PTEN expression is lost in many cancers, and even small changes in PTEN activity affect susceptibility and prognosis in a range of highly aggressive malignancies, such as melanoma and triple-negative breast cancer (TNBC). Loss of PTEN expression occurs via multiple mechanisms, including mutation, transcriptional repression and epigenetic silencing. Transcriptional repression of PTEN contributes to resistance to inhibitors used in the clinic, such as B-Raf inhibitors in BRAF mutant melanoma. We aimed to activate PTEN expression using the CRISPR system, specifically dead (d) Cas9 fused to the transactivator VP64-p65-Rta (VPR). dCas9-VPR was directed to the PTEN proximal promoter by single-guide RNAs (sgRNAs), in cancer cells that exhibited low levels of PTEN expression. The dCas9-VPR system increased PTEN expression in melanoma and TNBC cell lines, without transcriptional regulation at predicted off-target sgRNA binding sites. PTEN activation significantly repressed downstream oncogenic pathways, including AKT, mTOR, and MAPK signaling. BRAF V600E mutant melanoma cells transduced with dCas9-VPR displayed reduced migration, as well as diminished colony formation in the presence of B-Raf inhibitors, PI3K/mTOR inhibitors, and with combined PI3K/mTOR and B-Raf inhibition. CRISPR-mediated targeted activation of PTEN may provide an alternative therapeutic approach for highly aggressive cancers that are refractory to current treatments.

Metabolism and Epigenetic Interplay in Cancer: Regulation and Putative Therapeutic Targets

Alterations in the epigenome and metabolism affect molecular rewiring of cancer cells facilitating cancer development and progression. Modulation of histone and DNA modification enzymes occurs owing to metabolic reprogramming driven by oncogenes and expression of metabolism-associated genes is, in turn, epigenetically regulated, promoting the well-known metabolic reprogramming of cancer cells and, consequently, altering the metabolome. Thus, several malignant traits are supported by the interplay between metabolomics and epigenetics, promoting neoplastic transformation. In this review we emphasize the importance of tumour metabolites in the activity of most chromatin-modifying enzymes and implication in neoplastic transformation. Furthermore, candidate targets deriving from metabolism of cancer cells and altered epigenetic factors is emphasized, focusing on compounds that counteract the epigenomic-metabolic interplay in cancer.

Identification of a PTEN mutation with reduced protein stability, phosphatase activity, and nuclear localization in Hong Kong patients with autistic features, neurodevelopmental delays, and macrocephaly

PTEN is a tumor suppressor gene inactivated in over 30% of human cancers. It encodes a lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase signaling pathway. Germline mutation frequently occurs in this gene in patients diagnosed with PTEN Hamartoma Tumor Syndrome (PHTS). PHTS individuals are characterized by macrocephaly, benign growth of multiple tissues and increased tumor risk. In addition, autistic phenotypes are found in 10-20% of individuals carrying the germline PTEN mutation with macrocephaly. In this report, 13 suspected PHTS patients were screened for mutation in the PTEN gene. A missense variant (c. 302T > C) substituting the isoleucine at codon 101 to a threonine, a single nucleotide insertion (c. 327-328insC) causing a frame shift mutation and termination at codon 109, and a nonsense variant (c. 1003C > T) truncated the protein at codon 335 were identified. The I101T mutation significantly reduced PTEN protein expression levels by 2.5- to 4.0-fold. Mechanistically, I101T reduced the protein half-life of PTEN possibly due to enhanced polyubiquitination at Lysine 13. However, the I101T mutant retained almost 30% of the lipid phosphatase activity of the wild-type protein. Finally, the I101T mutant has reduced phosphorylation at a PTEN auto-dephosphorylation site at Threonine 366 and a lowered ratio of nuclear to cytosolic protein level. These partial losses of multiple PTEN biochemical functions may contribute to the tissue overgrowth and autistic features of this PHTS patient. Autism Res 2018, 11: 1098-1109. © 2018 The Authors Autism Research published by International Society for Autism Research and Wiley Periodicals, Inc. LAY SUMMARY: The genetics of autism spectrum disorders is highly complex with individual risk influenced by both genetic and environmental factors. Mutation in the human PTEN gene confers a high risk of developing autistic behavior. This report revealed that PTEN mutations occurred in 23% of a selected group of Hong Kong patients harboring autistic features with gross overgrowth symptoms. Detailed characterization of a PTEN mutation revealed reduced protein stability as one of the underlying mechanisms responsible for reduced PTEN activity.

miR-205 inhibits cell growth by targeting AKT-mTOR signaling in progesterone-resistant endometrial cancer Ishikawa cells

PURPOSE

miR-205 is significantly up-regulated in endometrioid adenocarcinoma. In this study, the significant anticancer effect of a miR-205 inhibitor was investigated in both endometrial carcinoma and progesterone-resistant endometrial carcinoma cells.

RESULTS

Compared with Ishikawa endometrial cancer cells, miR-205 was expressed at higher levels in a progesterone-resistant (PR) sub-cell line. Inhibition of miR-205 suppressed the growth of cancer cells in a dose- and time-dependent manner. Moreover, the miR-205 inhibitor induced a marked increase in the percentage of Ishikawa-PR cells in G2/M phases and a decrease in the percentage of cells in G0/G1 and S phases. In addition, miR-205 inhibitor-treated tumor cells exhibited increased apoptosis. Moreover, miR-205 was found to negatively regulate PTEN expression and lead to autophagy and activation of the AKT/mTOR pathway in PR cells, and PTEN protein levels significantly decreased with development of progesterone resistance in endometrial cancer cells. Western blot assay showed up-regulated autophagy, as indicated by expression of LC3-II/LC3-I and beclin1, in Ishikawa cells; in particular, autophagy was markedly induced in PR cells treated with the miR-205 inhibitor.

MATERIALS AND METHODS

We measured and analyzed cell growth curves with and without miR-205 inhibition with the MTT assay, miR-205 expression by qRT-PCR, cell cycle and apoptosis using annexin V/propidium iodide staining and flow cytometry, and autophagy, apoptosis, and AKT-mTOR signaling by western blotting.

CONCLUSIONS

Inhibition of miR-205, which targets the AKT-mTOR pathway, in endometrial cancer cells provides a potential, new treatment for PR endometrial carcinoma.

Current Insights into Oral Cancer Epigenetics

Epigenetic modifications have emerged into one of the cancer hallmarks, replacing the concept of malignant pathologies as being solely genetic-based conditions. The epigenetic landscape is responsible for normal development but also for the heterogeneity among tissues in terms of gene expression patterns. Dysregulation in these mechanisms has been associated with disease stage, and increased attention is now granted to cancer in order to take advantage of these modifications in terms of novel therapeutic strategies or diagnosis/prognosis tools. Oral cancer has also been subjected to epigenetic analysis with numerous studies revealing that the development and progression of this malignancy are partially induced by an altered epigenetic substrate together with genetic alterations and prolonged exposure to environmental risk factors. The present review summarizes the most important epigenetic modifications associated with oral cancer and also their potential to be used as new therapeutic targets.

Aberrant Promoter Methylation of PTEN Gene among Indian Patients with Oral Squamous Cell Carcinoma

Background and aims

Oral cancer is the second most common cancer in men and accounts for 50%-70% of the total cancer mortality in India. PTEN is a tumor suppressor gene that plays a critical role in controlling cell growth and survival. Promoter hypermethylation of the PTEN gene has been reported in many tumors. However, little is known about the association between promoter methylation and oral squamous cell carcinoma (OSCC). Therefore, we aimed to detect the role of PTEN hypermethylation in OSCC patients in the Indian population.

Methods

Genomic DNA was isolated from 100 fresh oral tumor specimens and was subjected to bisulfite conversion. Methylation-specific PCR was employed on the converted DNA to investigate the methylation status.

Results

Of the total cases examined for PTEN promoter methylation we found that 35% were positive and 65% were negative. When evaluated in connection with tumor differentiation it was found that 82% of poorly differentiated, 24% of moderately differentiated and 32% of well differentiated OSCC samples were methylated. Methylation was further correlated with patient age, sex and tumor grade. Interestingly, we found that patient age and grade of differentiation were significantly associated with PTEN promoter methylation (p=0.05 and 0.0019, respectively) while sex was not (p=0.9).

Conclusions

The present study underlines the importance of PTEN hypermethylation among Indian OSCC patients.

Epigenetics in endometrial carcinogenesis - part 1: DNA methylation

Carcinogenesis is a multistep multifactorial process that involves the accumulation of genetic and epigenetic alterations. In the past two decades, there has been an exponential growth of knowledge establishing the importance of epigenetic changes in cancer. Our work focused on reviewing the main role of epigenetics in the pathogenesis of endometrial carcinoma, highlighting the reported results concerning each epigenetic mechanistic layer. The present review is the first part of this work, in which we examined the contribution of DNA methylation alterations for endometrial carcinogenesis.

DNA methylation in lung tissues of mouse offspring exposed in utero to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) comprise an important class of environmental pollutants that are known to cause lung cancer in animals and are suspected lung carcinogens in humans. Moreover, evidence from cell-based studies points to PAHs as modulators of the epigenome. The objective of this work was to assess patterns of genome-wide DNA methylation in lung tissues of adult offspring initiated in utero with the transplacental PAH carcinogens dibenzo [def,p]chrysene (DBC) or benzo [a]pyrene (BaP). Genome-wide methylation patterns for normal (not exposed), normal adjacent and lung tumor tissues obtained from adult offspring were determined using methylated DNA immunoprecipitation (MeDIP) with the NimbleGen mouse DNA methylation CpG island array. Lung tumor incidence in 45-week old mice initiated with BaP was 32%, much lower than that of the DBC-exposed offspring at 96%. Also, male offspring appeared more susceptible to BaP as compared to females. Distinct patterns of DNA methylation were associated with non-exposed, normal adjacent and adenocarcinoma lung tissues, as determined by principal components, hierarchical clustering and gene ontology analyses. From these methylation profiles, a set of genes of interest was identified that includes potential important targets for epigenetic modification during the process of lung tumorigenesis in animals exposed to environmental PAHs.