DNA Methylation Controls Metastasis-Suppressive 14q32-Encoded miRNAs

Understanding the role of DNA methylation in colorectal cancer: Mechanisms, detection, and clinical significance

Colorectal cancer (CRC) is one of the deadliest malignancies worldwide, ranking third in incidence and second in mortality. Remarkably, early stage localized CRC has a 5-year survival rate of over 90%; in stark contrast, the corresponding 5-year survival rate for metastatic CRC (mCRC) is only 14%. Compounding this problem is the staggering lack of effective therapeutic strategies. Beyond genetic mutations, which have been identified as critical instigators of CRC initiation and progression, the importance of epigenetic modifications, particularly DNA methylation (DNAm), cannot be underestimated, given that DNAm can be used for diagnosis, treatment monitoring and prognostic evaluation. This review addresses the intricate mechanisms governing aberrant DNAm in CRC and its profound impact on critical oncogenic pathways. In addition, a comprehensive review of the various techniques used to detect DNAm alterations in CRC is provided, along with an exploration of the clinical utility of cancer-specific DNAm alterations.

Hypermethylated ITGA8 Facilitate Bladder Cancer Cell Proliferation and Metastasis

DNA methylation plays a vital role during the development of tumorigenesis. The purpose of this study is to identify candidate DNA methylation drivers during progression of bladder cancer (BLCA). The methylation spectrum in bladder cancer tissues was detected by CHARM analysis, and methylated ITGA8 was selected for further study due to its low expression. Methylation levels in BLCA tissues and cells were detected with methylated-specific PCR (MSP), while mRNA expression and methylation of ITGA8 were detected by qRT-PCR and MSP. After treatment with 5-Aza-dC (DNA methylation inhibitor), the proliferation, migration, and invasion abilities of BLCA cells were determined by MTT, wound healing, and transwell assays, respectively. Flow cytometric analysis was performed to evaluate any variance in the cell cycle. In addition, the effect of demethylated ITGA8 on BLCA tumor growth was verified with an in vivo xenograft tumor model. Based on the methylation profiling of BLCA, ITGA8 was identified to be hypermethylated. ITGA8 methylation levels in BLCA tissues and cells were upregulated, and 5-Aza-dC significantly suppressed ITGA8 methylation levels and increased ITGA8 mRNA expression. Furthermore, after treatment with 5-Aza-dC, the propagation, migration, and invasiveness of the cancer cells were inhibited, and more cancer cells were arrested at the G0/G1 phase. In vivo assays further demonstrated that 5-Aza-dC could impede BLCA tumor growth by repressing methylation levels of ITGA8 and increasing ITGA8 mRNA expression. Hypermethylated ITGA8 facilitated BLCA progression, and 5-Aza-dC treatment inhibited BLCA cell propagation and metastasis by decreasing methylation levels of ITGA8 and inducing cell cycle arrest.

Oligometastases: Characterizing the Role of Epigenetic Regulation of Epithelial-Mesenchymal Transition

The "oligometastasis" hypothesis proposes that metastases exist as a spectrum and are not always disseminated. According to this theory, a subset of patients with metastatic disease could benefit from aggressive local therapies. However, the identification of patients most likely to exhibit an oligometastatic phenotype remains challenging. Recent literature focusing on basic and translational studies has identified novel epigenetic regulators of epithelial-mesenchymal transition (EMT) and the emergence of a spectrum of metastatic behavior. Herein, we review these scientific advances and suggest that the spectrum of metastatic virulence produced by these epigenetic mechanisms broadly contributes to the emergence of clinically evident "oligometastases." Epigenetic regulation of EMT programs can result in a spectrum of cell trajectories (e.g., quasi-mesenchymal and highly mesenchymal states) with differential propensity to develop metastases. We propose that quasi-mesenchymal cell states may be associated with a polymetastatic phenotype, whereas highly mesenchymal cell states may be associated with a more oligometastatic phenotype. The mechanisms governing epigenetic regulation of EMT and its array of intermediate states are multifaceted and may contribute to the development of the metastatic spectrum observed clinically. Within this context, translational studies that support the role of EMT and its epigenetic regulation are discussed. Continued translation of these mechanistic discoveries into novel biomarkers may help optimally select patients most likely to exhibit an oligometastatic phenotype and benefit from aggressive local therapies, such as surgery, radiotherapy, and other ablative procedures.

Deregulated expression of the 14q32 miRNA cluster in clear cell renal cancer cells

Clear cell renal cell carcinomas (ccRCC) are characterized by arm-wide chromosomal alterations. Loss at 14q is associated with disease aggressiveness in ccRCC, which responds poorly to chemotherapeutics. The 14q locus contains one of the largest miRNA clusters in the human genome; however, little is known about the contribution of these miRNAs to ccRCC pathogenesis. In this regard, we investigated the expression pattern of selected miRNAs at the 14q32 locus in TCGA kidney tumors and in ccRCC cell lines. We demonstrated that the miRNA cluster is downregulated in ccRCC (and cell lines) as well as in papillary kidney tumors relative to normal kidney tissues (and primary renal proximal tubule epithelial (RPTEC) cells). We demonstrated that agents modulating expression of DNMT1 (e.g., 5-Aza-deoxycytidine) could modulate 14q32 miRNA expression in ccRCC cell lines. Lysophosphatidic acid (LPA, a lysophospholipid mediator elevated in ccRCC) not only increased labile iron content but also modulated expression of a 14q32 miRNA. Through an overexpression approach targeting a subset of 14q32 miRNAs (specifically at subcluster A: miR-431-5p, miR-432-5p, miR-127-3p, and miR-433-3p) in 769-P cells, we uncovered changes in cellular viability and claudin-1, a tight junction marker. A global proteomic approach was implemented using these miRNA overexpressing cell lines which uncovered ATXN2 as a highly downregulated target. Collectively, these findings support a contribution of miRNAs at 14q32 in ccRCC pathogenesis.

SURGICAL TREATMENT AS AN INCREASE IN THE SURVIVAL OF PATIENTS WITH LIVER OLIGOMETASTASIS OF DUCTAL ADENOCARCINOMA OF THE PANCREAS. PATIENT SELECTION CRITERIA. REVIEW

The work is based on the analysis of the literature data on the problems of treating patients with metastatic pancreatic cancer, identifying a group of patients with more favorable treatment prognosis. The objectives of this review are to study diagnostic criteria, to determine the optimal algorithm for the diagnosis and treatment of patients with oligometastatic pancreatic disease. According to the Global Cancer Observatory (GLOBOCAN) in the world, in 2020 the incidence of pancreatic cancer among men and women was about 7.2 and 5.0 per 100 thousand, with a mortality rate of 6.7 and 4.6 %, respectively [1]. At the same time, in most cases, the disease is diagnosed at stage IIIIV, so the results of treatment remain unsatisfactory, 2/3 of patients die within 1 year after the diagnosis is made. The "gold standard" for the treatment of this group of patients today is only systemic antitumor therapy according to the FOLFRINOX regimen, in which the average overall survival is about 11.1 months. Thanks to the development of ideas about the mechanisms of tumor progression, the improvement of diagnostic methods and antitumor treatment, the concept of oligometastatic disease has appeared and is being actively studied. According to the current theory, this group of patients with stage IV tumors can potentially have a better prognosis. The analysis of modern domestic and foreign literature is carried out. According to scientific studies, careful selection and implementation of combined treatment can significantly increase the survival rate of this group of patients. Based on numerous studies, some authors have proposed optimal algorithms for the diagnosis and treatment of patients with oligometastatic pancreatic disease.

Effects of selective inhibition of prostaglandin E2 receptors EP2 and EP4 on the miRNA profile in endometriosis

Endometriosis is an estrogen-dependent, progesterone-resistant, chronic inflammatory gynecological disease of reproductive-age women. Two major clinical symptoms of endometriosis are chronic pelvic pain and infertility, which profoundly affect the quality of life in women. Current hormonal therapies to induce a hypoestrogenic state are unsuccessful because of undesirable side effects, reproductive health concerns, and failure to prevent disease recurrence. Prostaglandin E₂ (PGE₂) plays an important role in the survival and growth of endometriotic lesions. MicroRNAs (miRNAs) are small, noncoding RNAs that control gene expressions through multiple mechanisms and have important roles in the pathogenesis of endometriosis. The objective of the present study is to determine the effects of pharmacological inhibition of PGE₂ receptors, EP2 and EP4, on miRNA profile in endometriosis. The novel results collectively indicate that inhibition of PGE₂-EP2/EP4 signaling regulated several miRNA clusters associated with cell adhesion, migration, invasion, survival and growth in cell-specific and the chromosome-specific manner and reverses the epigenetic silencing of proapoptotic miRNAs 15a and 34c in the human endometriotic epithelial and stromal cells and experimental endometriotic lesions. Thus, selective inhibition of EP2/EP4 receptors could emerge as a potential nonsteroidal therapy for endometriosis.

KIF17 maintains the epithelial phenotype of breast cancer cells and curbs tumour metastasis

Kinesin superfamily motor protein 17 (KIF17) was previously identified downregulated in breast cancer and correlated with patient prognosis. However, its pathophysiological role in tumours remains unknown. Here, we confirmed that KIF17 was significantly under-expressed in breast cancer tissues and low KIF17 expression correlated with poor outcomes in patients with breast cancer. In vitro and in vivo experiments demonstrated that KIF17 overexpression in breast cancer cell lines significantly inhibited breast cancer invasion and metastasis. By establishing the lung metastatic MDA-MB-231 cell lines, we found a transient silence of KIF17 during the initiation of breast cancer metastasis. Further experiments revealed that KIF17 might suppress metastasis by regulating the level of acetylated tubulin to maintain cytoskeleton stability. Eventually, we found that the low expression of KIF17 in breast cancer is regulated by DNMT1-mediated 5-mC DNA methylation and epigenetic silencing. Decitabine can effectively improve the expression level of KIF17 in breast cancer cells. Our study demonstrates that KIF17 mediates microtubule acetylation to maintain the stability of microtubules, thereby inhibiting tumour invasion and metastasis.

Oligometastatic Disease in the Liver: The Role of Interventional Oncology

Oligometastatic disease represents a clinically discrete intermediate stage of cancer progression and is an expanding area of research. While surgical metastatectomy has been recognized for decades as an effective treatment option in select patients, options for metastasis-directed therapy have broadened in scope with advancements in the armamentarium of non- and minimally invasive modalities. Recent preclinical studies investigating the immunology surrounding liver metastases demonstrate treatment resistance to immunotherapy in affected patients and show how locoregional therapy has the ability to overcome this resistance. In this paper, we review advancements in our understanding of oligometastatic disease, metastasis-directed therapy, effect of liver metastasis on response to immunotherapy, and the burgeoning role of image-guided interventions in complementing cancer immunotherapy at the exciting crossroads of interventional oncology and immuno-oncology.

PKIB involved in the metastasis and survival of osteosarcoma

Osteosarcoma is frequently metastasized at the time of diagnosis in patients. However, the underlying mechanism of osteosarcoma metastasis remains poorly understood. In this study, we evaluated DNA methylation profiles combined with gene expression profiles of 21 patients with metastatic osteosarcoma and 64 patients with non-metastatic osteosarcoma from TARGET database and identified PKIB and AIM2 as hub genes related to the metastasis of osteosarcoma. To verify the effects of PKIB on migration and invasion of osteosarcoma, we performed wound-healing assay and transwell assay. The results showed that PKIB significantly inhibited the migration and invasion of osteosarcoma cells, and the Western blot experiments showed that the protein level of E-cad was upregulated and of VIM was downregulated in 143-B cell recombinant expression PKIB. These results indicate that PKIB inhibit the metastasis of osteosarcoma. CCK-8 assay results showed that PKIB promote the proliferation of osteosarcoma. In addition, the Western blot results showed that the phosphorylation level of Akt was upregulated in 143-B cells overexpressing PKIB, indicating that PKIB promotes the proliferation of osteosarcoma probably through signaling pathway that Akt involved in. These results give us clues that PKIB was a potential target for osteosarcoma therapy. Furthermore, combined clinical profiles analysis showed that the expression of AIM2- and PKIB- related risk scores was significantly related to the overall survival of patients with osteosarcoma. Thus, we constructed a nomogram based on AIM2 and PKIB expression–related risk scores for osteosarcoma prognostic assessment to predict the 1-, 2-, 3-, and 5-year overall survival rate of patients with metastatic osteosarcoma, assisting clinicians in the diagnosis and treatment of metastatic osteosarcoma.

The oligometastatic spectrum in the era of improved detection and modern systemic therapy

Metastases remain the leading cause of cancer-related mortality. The oligometastasis hypothesis postulates that a spectrum of metastatic spread exists and that some patients with a limited burden of metastases can be cured with ablative therapy. Over the past decade, substantial advances in systemic therapies have resulted in considerable improvements in the outcomes of patients with metastatic cancers, warranting re-examination of the oligometastatic paradigm and the role of local ablative therapies within the context of the improved therapeutic responses, shifting patterns of disease recurrence and possible synergy with systemic treatments. Herein, we reframe the oligometastatic phenotype as a dynamic state for which locally ablative, metastasis-directed therapy improves clinical outcomes, including by prolonging survival and increasing cure rates. Important risk factors defining the metastatic spectrum are highlighted that inform both staging and therapy. Finally, we synthesize the literature on combining local therapies with modern systemic treatments, identifying general themes to optimally integrate ablative therapies in this context.

Current treatment landscape for oligometastatic non-small cell lung cancer

The management of patients with advanced non-small cell lung carcinoma (NSCLC) has undergone major changes in recent years. On the one hand, improved sensitivity of diagnostic tests, both radiological and endoscopic, has altered the way patients are staged. On the other hand, the arrival of new drugs with antitumoral activity, such as targeted therapies or immunotherapy, has changed the prognosis of patients, improving disease control and prolonging survival. Finally, the development of radiotherapy and surgical and interventional radiology techniques means that radical ablative treatments can be performed on metastases in any location in the body. All of these advances have impacted the treatment of patients with advanced lung cancer, especially in a subgroup of these patients in which all of these treatment modalities converge. This poses a challenge for physicians who must decide upon the best treatment strategy for each patient, without solid evidence for one optimal mode of treatment in this patient population. The aim of this article is to review, from a practical and multidisciplinary perspective, published evidence on the management of oligometastatic NSCLC patients. We evaluate the different alternatives for radical ablative treatments, the role of primary tumor resection or radiation, the impact of systemic treatments, and the therapeutic sequence. In short, the present document aims to provide clinicians with a practical guide for the treatment of oligometastatic patients in routine clinical practice.

The Interaction Between Epigenetic Changes, EMT, and Exosomes in Predicting Metastasis of Colorectal Cancers (CRC)

Worldwide, colorectal cancer (CRC) ranks as the third most common malignancy, and the second most deadly with nearly one million attributable deaths in 2020. Metastatic disease is present in nearly 25% of newly diagnosed CRC, and despite advances in chemotherapy, less than 20% will remain alive at 5 years. Epigenetic change plays a key role in the epithelial-to-mesenchymal transition (EMT), which is a crucial phenotype for metastasis and mainly includes DNA methylation, non-coding RNAs (ncRNAs), and N6-methyladenosine (m6A) RNA, seemingly valuable biomarkers in CRCs. For ncRNAs, there exists a “molecular sponge effect” between long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs). The detection of exosomes is a novel method in CRC monitoring, especially for predicting metastasis. There is a close relationship between exosomes and EMT in CRCs. This review summarizes the close relationship between epigenetic changes and EMT in CRCs and emphasizes the crucial function of exosomes in regulating the EMT process.

The role of epigenetic modifications in Colorectal Cancer Metastasis

Distant metastasis is the major contributor to the high mortality rate of colorectal cancer (CRC). To overcome the poor prognosis caused by distant metastasis, the mechanisms of CRC metastasis should be further explored. Epigenetic events are the main mediators of gene regulation and further affect tumor progression. Recent studies have found that some epigenetic enzymes are often dysregulated or mutated in multiple tumor types, which prompted us to study the roles of these enzymes in CRC metastasis. In this review, we summarized the alteration of enzymes related to various modifications, including histone modification, nonhistone modification, DNA methylation, and RNA methylation, and their epigenetic mechanisms during the progression of CRC metastasis. Existing data suggest that targeting epigenetic enzymes is a promising strategy for the treatment of CRC metastasis.

Cooperative miRNA-dependent PTEN regulation drives resistance to BTK inhibition in B-cell lymphoid malignancies

Aberrant microRNA (miR) expression plays an important role in pathogenesis of different types of cancers, including B-cell lymphoid malignancies and in the development of chemo-sensitivity or -resistance in chronic lymphocytic leukemia (CLL) as well as diffuse large B-cell lymphoma (DLBCL). Ibrutinib is a first-in class, oral, covalent Bruton's tyrosine kinase (BTK) inhibitor (BTKi) that has shown impressive clinical activity, yet many ibrutinib-treated patients relapse or develop resistance over time. We have reported that acquired resistance to ibrutinib is associated with downregulation of tumor suppressor protein PTEN and activation of the PI3K/AKT pathway. Yet how PTEN mediates chemoresistance in B-cell malignancies is not clear. We now show that the BTKi ibrutinib and a second-generation compound, acalabrutinib downregulate miRNAs located in the 14q32 miRNA cluster region, including miR-494, miR-495, and miR-543. BTKi-resistant CLL and DLBCL cells had striking overexpression of miR-494, miR-495, miR-543, and reduced PTEN expression, indicating further regulation of the PI3K/AKT/mTOR pathway in acquired BTKi resistance. Additionally, unlike ibrutinib-sensitive CLL patient samples, those with resistance to ibrutinib treatment, demonstrated upregulation of 14q32 cluster miRNAs, including miR-494, miR-495, and miR-543 and decreased pten mRNA expression. Luciferase reporter gene assay showed that miR-494 directly targeted and suppressed PTEN expression by recognizing two conserved binding sites in the PTEN 3'-UTR, and subsequently activated AKT^Ser473. Importantly, overexpression of a miR-494 mimic abrogated both PTEN mRNA and protein levels, further indicating regulation of apoptosis by PTEN/AKT/mTOR. Conversely, overexpression of a miR-494 inhibitor in BTKi-resistant cells restored PTEN mRNA and protein levels, thereby sensitizing cells to BTKi-induced apoptosis. Inhibition of miR-494 and miR-495 sensitized cells by cooperative targeting of pten, with additional miRNAs in the 14q32 cluster that target pten able to contribute to its regulation. Therefore, targeting 14q32 cluster miRNAs may have therapeutic value in acquired BTK-resistant patients via regulation of the PTEN/AKT/mTOR signaling axis.

The Spectrum of Metastasis: An Opportunity for Cure?

In this review, we outline the clinical and biologic evidence supporting the existence of an oligometastatic state. We first discuss the surgical and radiotherapeutic data that demonstrate clear benefits to cancer-specific outcomes with local ablative therapy in subsets of patients with metastatic disease. We then delve into the evolving preclinical and translational studies already beginning to define the biology of oligometastasis, with a specific focus on the genetics, epigenetics, and immunologic aspects of oligometastatic disease. We conclude by highlighting the importance of focusing significant effort as a research community on developing an integrated clinical-molecular classification of metastatic disease to personalize treatment for patients with potentially curable oligometastatic disease.

[A Review of Epigenetic Modifications Regulate MicroRNA Expression in Lung Cancer]

肺癌是全世界癌症引起死亡中较常见的一种。近年来，参与肺癌发病的分子机制被逐步揭开，但是其发生发展的确切机制并未完全阐明。其中微小RNAs（microRNAs, miRNAs）是一种短小并且广泛存在于植物、病毒及人类等各种生物中的内源性单链的非编码RNA。miRNAs在正常肺组织中发挥着多种功能，它参与细胞生长、代谢、增殖和分化等众多生物学过程。而miRNAs的异常表达与肺肿瘤的发生、发展、侵袭、转移相关。因此，miRNAs可被视为一种新的生物标志物。与编码蛋白质的基因类似，miRNA的表达和功能受多种因素以及表观遗传网络（包括DNA甲基化和组蛋白修饰机制）的调控。此外，miRNAs本身也能调控那些表观遗传修饰的关键酶来影响表观修饰。miRNA与表观基因学之间的相互联系将有助于我们研发以miRNA为导向的肺癌诊断、治疗和预后的方案。

The long and the small collide: LncRNAs and small heterodimer partner (SHP) in liver disease

Long non-coding RNAs (lncRNAs) are a large and diverse class of RNA molecules that are transcribed but not translated into proteins, with a length of more than 200 nucleotides. LncRNAs are involved in gene expression and regulation. The abnormal expression of lncRNAs is associated with disease pathogenesis. Small heterodimer partner (SHP, NR0B2) is a unique orphan nuclear receptor that plays a pivotal role in many biological processes by acting as a transcriptional repressor. In this review, we present the critical roles of SHP and summarize recent findings demonstrating the regulation between lncRNAs and SHP in liver disease.

Essential Role of the 14q32 Encoded miRNAs in Endocrine Tumors

BACKGROUND

The 14q32 cluster is among the largest polycistronic miRNA clusters. miRNAs encoded here have been implicated in tumorigenesis of multiple organs including endocrine glands.

METHODS

Critical review of miRNA studies performed in endocrine tumors have been performed. The potential relevance of 14q32 miRNAs through investigating their targets, and integrating the knowledge provided by literature data and bioinformatics predictions have been indicated.

RESULTS

Pituitary adenoma, papillary thyroid cancer and a particular subset of pheochromocytoma and adrenocortical cancer are characterized by the downregulation of miRNAs encoded by the 14q32 cluster. Pancreas neuroendocrine tumors, most of the adrenocortical cancer and medullary thyroid cancer are particularly distinct, as 14q32 miRNAs were overexpressed. In pheochromocytoma and growth-hormone producing pituitary adenoma, however, both increased and decreased expression of 14q32 miRNAs cluster members were observed. In the background of this phenomenon methodological, technical and biological factors are hypothesized and discussed. The functions of 14q32 miRNAs were also revealed by bioinformatics and literature data mining.

CONCLUSIONS

14q32 miRNAs have a significant role in the tumorigenesis of endocrine organs. Regarding their stable expression in the circulation of healthy individuals, further investigation of 14q32 miRNAs could provide a potential for use as biomarkers (diagnostic or prognostic) in endocrine neoplasms.

Oligometastasis: Past, Present, Future

In this review, we discuss the oligometastatic state, with a focus on its current and future relevance within the field of radiation therapy. We first outline the scope of the problem and the evolving understanding of metastatic disease existing along a spectrum. We then transition to a discussion of the clinical data that led to the formulation of the oligometastatic hypothesis, delving in some detail into the clinical factors associated with improved outcomes in the setting of local therapy-whether surgical or radiotherapeutic. In particular, we highlight the marked limitations of using clinical criteria alone to determine the absence or presence of true extracranial oligometastatic disease. After this, we briefly discuss the radiation therapy literature that has recently demonstrated benefits in cancer-specific outcomes with ablative treatment of oligometastatic disease. We emphasize data in the setting of non-small cell lung cancer and prostate cancer and briefly discuss the importance of our enhanced ability to detect occult metastatic disease with improved imaging technologies. After noting that resulted and ongoing prospective trials of ablative radiation therapy use the most rudimentary of oligometastatic classifiers-number of metastases-as their inclusion criteria, we transition to our core argument: a growing body of preclinical and translational work aims to refine the definition of oligometastatic disease using molecular features. We address genomic, epigenetic, and immunologic features that have, across histology, demonstrated an improved ability to prognosticate when combined with classic clinical correlates of oligometastatic disease. We also discuss studies that suggest particular molecular targets which, when manipulated for therapeutic purposes, have the potential to revert the polymetastatic phenotype to the oligometastatic one. We conclude with what we believe are the repercussions of this work for radiation therapy trials and clinical practice, and the importance of enriching and supporting these inquiries for the future of our field.

MicroRNA: A signature for cancer progression

MicroRNAs (miRNAs) are a group of small non-coding RNAs that post-transcriptionally control expression of genes by targeting mRNAs. miRNA alterations partake in the establishment and progression of different types of human cancer. Consequently, expression profiling of miRNA in human cancers has correlations with cancer detection, staging, progression, and response to therapies. Particularly, amplification, deletion, abnormal pattern of epigenetic factors and the transcriptional factors that mediate regulation of primary miRNA frequently change the landscape of miRNA expression in cancer. Indeed, changes in the quantity and quality of miRNAs are associated with the initiation of cancer, its progression and metastasis. Additionally, miRNA profiling has been used to categorize genes that can affect oncogenic pathways in cancer. Here, we discuss several circulating miRNA signatures, their expression profiles in different types of cancer and their impacts on cellular processes.

Global miRNA/proteomic analyses identify miRNAs at 14q32 and 3p21, which contribute to features of chronic iron-exposed fallopian tube epithelial cells

Malignant transformation of fallopian tube secretory epithelial cells (FTSECs) is a key contributing event to the development of high-grade serous ovarian carcinoma (HGSOC). Our recent findings implicate oncogenic transformative events in chronic iron-exposed FTSECs, including increased expression of oncogenic mediators, increased telomerase transcripts, and increased growth/migratory potential. Herein, we extend these studies by implementing an integrated transcriptomic and mass spectrometry-based proteomics approach to identify global miRNA and protein alterations, for which we also investigate a subset of these targets to iron-induced functional alterations. Proteomic analysis identified > 4500 proteins, of which 243 targets were differentially expressed. Sixty-five differentially expressed miRNAs were identified, of which 35 were associated with the “top” proteomic molecules (> fourfold change) identified by Ingenuity Pathway Analysis. Twenty of these 35 miRNAs are at the 14q32 locus (encoding a cluster of 54 miRNAs) with potential to be regulated by DNA methylation and histone deacetylation. At 14q32, miR-432-5p and miR-127-3p were ~ 100-fold downregulated whereas miR-138-5p was 16-fold downregulated at 3p21 in chronic iron-exposed FTSECs. Combinatorial treatment with methyltransferase and deacetylation inhibitors reversed expression of these miRNAs, suggesting chronic iron exposure alters miRNA expression via epigenetic alterations. In addition, PAX8, an important target in HGSOC and a potential miRNA target (from IPA) was epigenetically deregulated in iron-exposed FTSECs. However, both PAX8 and ALDH1A2 (another IPA-predicted target) were experimentally identified to be independently regulated by these miRNAs although TERT RNA was partially regulated by miR-138-5p. Interestingly, overexpression of miR-432-5p diminished cell numbers induced by long-term iron exposure in FTSECs. Collectively, our global profiling approaches uncovered patterns of miRNA and proteomic alterations that may be regulated by genome-wide epigenetic alterations and contribute to functional alterations induced by chronic iron exposure in FTSECs. This study may provide a platform to identify future biomarkers for early ovarian cancer detection and new targets for therapy.

Demethylation of miR-34a upregulates expression of membrane palmitoylated proteins and promotes the apoptosis of liver cancer cells

BACKGROUND

Liver cancer is a common cancer and the main cause of cancer-related deaths worldwide. Liver cancer is the sixth most common cancer in the world. Although miR-34a and palmitoyl membrane palmitoylated protein (MPP2) are reportedly involved in various cell processes, their precise roles in liver cancer are still unclear.

AIM

To investigate the expression of micro RNA 34a (miR-34a), methylation of the miR-34a promoter and the expression of MPP2 in liver cancer cells and their related mechanisms.

METHODS

Together, 78 cases of liver cancer tissues and 78 cases of adjacent tissues were collected. The methylation degree of miR-34a promoter in liver cancer/ paracancerous tissue and liver cancer cells/normal liver cells, and the expression levels of miR-34a and MPP2 in the above samples were detected. Demethylation of liver cancer cells or transfection of liver cancer cells with miR-34a mimetic was performed. The MPP2 overexpression vector was used to transfect liver cancer cells, and the changes in proliferation, invasion, apoptosis, migration, and other biological functions of liver cancer cells after the above interventions were observed. Double luciferase reporter genes were used to detect the targeting relationship between miR-34a and MPP2.

RESULTS

Clinical samples showed that the expression levels of miR-34a and MPP2 in liver cancer tissues were lower than those in the normal tissues. The methylation degree of miR-34a promoter region in liver cancer cells was higher than that in normal liver cells. After miR-34a demethylation/mimetic transfection/MPP2 overexpression, the apoptosis of liver cancer cells was increased; the proliferation, invasion and migration capabilities were decreased; the expression levels of caspase 3, caspase 9, E-cadherin, and B-cell lymphoma 2 (Bcl-2)-associated X protein were increased; and the expression levels of Bcl-2, N-cadherin, and β-catenin were decreased. Double luciferase reporter genes confirmed that MPP2 is targeted by miR-34a. Rescue experiments showed that small interfering MPP2 could counteract the promoting effect of miR-34a demethylation on apoptosis and the inhibitory effect on cell proliferation, invasion, and migration.

CONCLUSION

miR-34a demethylation upregulates the expression level of MPP2 in liver cancer cells and promotes the apoptosis of liver cancer cells. miR-34a demethylation is a potential method for liver cancer treatment.

Long non-coding RNAs and cancer metastasis: Molecular basis and therapeutic implications

Cancer metastasis, defined by the epithelial to mesenchymal transition (EMT) of tumor cells, disseminates from the primary site to progressively colonize in distant tissues, and accounts for most cancer-associated deaths. However, studies on the molecular basis of cancer metastasis are still in their infancy. Besides genetic mutations, accumulating evidence indicates that epigenetic alterations also contribute in a major way to the refractory nature of cancer metastasis. Considered as one of the essential epigenetic regulators, long non-coding RNAs (lncRNAs) can act as signaling regulators, decoys, guides and scaffolds, modulating key molecules in every step of cancer metastasis including dissemination of carcinoma cells, intravascular transit, and metastatic colonization. Although still having limited clinical application, it is encouraging to witness that several lncRNAs, including CCAT1 and HOTAIR, are under clinical evaluation as potential biomarkers for cancer staging and assessment of metastatic potential. In this review, we focus on the molecular mechanisms underlying lncRNAs in the regulation of cancer metastasis and discuss their clinical potential as novel therapeutic targets as well as their diagnostic and prognostic significance for cancer treatment. Gaining clear insights into the detailed molecular basis underlying lncRNA-modulated cancer metastasis may provide previously unrecognized diagnostic and therapeutic strategies for metastatic patients.

(Oligo)metastasis as a Spectrum of Disease

Cancer metastasis is the leading cause of cancer-related mortality, and most patients with metastases from solid tumors have historically been considered incurable. Here, we discuss the evolution of our understanding of the oligometastatic state with an emphasis on the view that cancer metastasis represents a spectrum of disease. We highlight several recently published prospective clinical trials demonstrating improvements in cancer-specific outcomes with the utilization of metastasis-directed local therapies. We discuss biological aspects of oligometastases, including genetic, epigenetic, and immune determinants of the metastatic spectrum. Finally, we propose future considerations regarding clinical trial design for patients with oligometastatic disease.

A MicroRNA Cluster in the DLK1-DIO3 Imprinted Region on Chromosome 14q32.2 Is Dysregulated in Metastatic Hepatoblastomas

Hepatoblastoma (HB) is the most common malignant liver neoplasm in children. Despite progress in HB therapy, outcomes for patients with metastatic disease remain poor. Dysregulation of miRNA expression is one of the potential epigenetic mechanisms associated with pathogenesis of HB. However, miRNA profiles related to the different stages of HB tissues and cells, in particular of lung metastatic tumor cells, are unknown. In the present study, using array-based miRNA expression and DNA methylation analysis on formalin-fixed paraffin-embedded tissues, we aimed to identify miRNA changes that can discriminate between lung metastatic tumors, primary tumors (fetal and embryonal subtypes), and nontumorous surrounding livers. Our analysis demonstrated that a large cluster of microRNAs and snoRNAs located within the 14q32.2 DLK1-DIO3 region showed a strikingly upregulated expression pattern in HB tumors, especially metastatic tumors, compared to normal liver tissues. This revealed dysregulation of miRNAs similar to that seen in a malignant stem-like subtype of hepatocellular carcinoma associated with poor prognosis. These findings in HB mirror similar findings made in multiple other cancer types. With further analysis this may in future allow stratification of different stages and types of HB tumors based on their miRNA profiles, which could lead to new approaches to diagnosis and treatment in progressive HB patients.

Multifaceted Roles of DNA Methylation in Neoplastic Transformation, from Tumor Suppressors to EMT and Metastasis

Among the major mechanisms involved in tumorigenesis, DNA methylation is an important epigenetic modification impacting both genomic stability and gene expression. Methylation of promoter-proximal CpG islands (CGIs) and transcriptional silencing of tumor suppressors represent the best characterized epigenetic changes in neoplastic cells. The global cancer-associated effects of DNA hypomethylation influence chromatin architecture and reactivation of repetitive elements. Moreover, recent analyses of cancer cell methylomes highlight the role of the DNA hypomethylation of super-enhancer regions critically controlling the expression of key oncogenic players. We will first summarize some basic aspects of DNA methylation in tumorigenesis, along with the role of dysregulated DNA methyltransferases and TET (Ten-Eleven Translocation)-family methylcytosine dioxygenases. We will then examine the potential contribution of epimutations to causality and heritability of cancer. By reviewing some representative genes subjected to hypermethylation-mediated silencing, we will survey their oncosuppressor functions and roles as biomarkers in various types of cancer. Epithelial-to-mesenchymal transition (EMT) and the gain of stem-like properties are critically involved in cancer cell dissemination, metastasis, and therapeutic resistance. However, the driver vs passenger roles of epigenetic changes, such as DNA methylation in EMT, are still poorly understood. Therefore, we will focus our attention on several aspects of DNA methylation in control of EMT and metastasis suppressors, including both protein-coding and noncoding genes.

Distinct Subsets of Noncoding RNAs Are Strongly Associated With BMD and Fracture, Studied in Weight-Bearing and Non-Weight-Bearing Human Bone

We investigated mechanisms resulting in low bone mineral density (BMD) and susceptibility to fracture by comparing noncoding RNAs (ncRNAs) in biopsies of non-weight-bearing (NWB) iliac (n = 84) and weight bearing (WB) femoral (n = 18) postmenopausal bone across BMDs varying from normal (T-score > -1.0) to osteoporotic (T-score ≤ -2.5). Global bone ncRNA concentrations were determined by PCR and microchip analyses. Association with BMD or fracture, adjusted by age and body mass index, were calculated using linear and logistic regression and least absolute shrinkage and selection operator (Lasso) analysis. At 10% false discovery rate (FDR), 75 iliac bone ncRNAs and 94 femoral bone ncRNAs were associated with total hip BMD. Eight of the ncRNAs were common for the two sites, but five of them (miR-484, miR-328-3p, miR-27a-5p, miR-28-3p, and miR-409-3p) correlated positively to BMD in femoral bone, but negatively in iliac bone. Of predicted pathways recognized in bone metabolism, ECM-receptor interaction and proteoglycans in cancer emerged at both sites, whereas fatty acid metabolism and focal adhesion were only identified in iliac bone. Lasso analysis and cross-validations identified sets of nine bone ncRNAs correlating strongly with adjusted total hip BMD in both femoral and iliac bone. Twenty-eight iliac ncRNAs were associated with risk of fracture (FDR < 0.1). The small nucleolar RNAs, RNU44 and RNU48, have a function in stabilization of ribosomal RNAs (rRNAs), and their association with fracture and BMD suggest that aberrant processing of rRNAs may be involved in development of osteoporosis. Cis-eQTL (expressed quantitative trait loci) analysis of the iliac bone biopsies identified two loci associated with microRNAs (miRNAs), one previously identified in a heel-BMD genomewide association study (GWAS). In this comprehensive investigation of the skeletal genetic background in postmenopausal women, we identified functional bone ncRNAs associated to fracture and BMD, representing distinct subsets in WB and NWB skeletal sites. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

The Emerging Roles of Heterochromatin in Cell Migration

Cell migration is a key process in health and disease. In the last decade an increasing attention is given to chromatin organization in migrating cells. In various types of cells induction of migration leads to a global increase in heterochromatin levels. Heterochromatin is required for optimal cell migration capabilities, since various interventions with heterochromatin formation impeded the migration rate of numerous cell types. Heterochromatin supports the migration process by affecting both the mechanical properties of the nucleus as well as the genetic processes taking place within it. Increased heterochromatin levels elevate nuclear rigidity in a manner that allows faster cell migration in 3D environments. Condensed chromatin and a more rigid nucleus may increase nuclear durability to shear stress and prevent DNA damage during the migration process. In addition, heterochromatin reorganization in migrating cells is important for induction of migration-specific transcriptional plan together with inhibition of many other unnecessary transcriptional changes. Thus, chromatin organization appears to have a key role in the cellular migration process.

CPS1 expression and its prognostic significance in lung adenocarcinoma

Background

Studies have increasingly shown that carbamoyl phosphate synthetase 1 (CPS1) plays a vital role in the occurrence and development of human malignant disease. Unfortunately, the detailed function of CPS1 in the development and prognosis of lung cancer, especially lung adenocarcinoma (LADC), is still not fully understood. In this research, we performed a comprehensive bioinformatics analysis with respect to the function of CPS1 in human LADC.

Methods

Several biological databases including UALCAN, GEPIA and Oncomine were used to analyze the expression of CPS1 in LADC. Meanwhile, TCGA and GEO databases were utilized to analyze relevant clinical data. In addition, databases including Methsurv, etc., were used to analyze CPS1 methylation levels in LADC.

Results

The Oncomine platform, UALCAN and gene expression profiling interactive analysis (GEPIA) were used and revealed that the expression levels of CPS1 were significantly increased in LADC tissues. Furthermore, we analyzed the methylation level of CPS1 in LADC and found that cases with high levels of CPS1 showed hypomethylated CPS1. The clinical data from the Wanderer database, which is linked to The Cancer Genome Atlas (TCGA) database, demonstrated that the expression and methylation values of CPS1 were both significantly related to the clinical characteristics and prognosis of LADC. Through analysis of the dataset from the Gene Expression Omnibus (GEO) database, we found that the expression level of CPS1 was markedly downregulated in human A549 lung cancer cells treated with the chemotherapeutic drug motexafin gadolinium (MGd) in a time-dependent manner.

Conclusions

Our work indicated that CPS1 is upregulated in LADC samples and that CPS1 might be used as a potential biomarker for the diagnostic and prognostic evaluation of LADC. Determining the detailed biological function of CPS1 in LADC tissues will provide promising and insightful information for our further study.

Oligometastatic Breast Cancer: Is This a Curable Entity? A Contemporary Review of the Literature

PURPOSE OF REVIEW

Oligometastatic breast cancer (OMBC) remains a poorly understood entity for which no standard of care exists at this time. This review will focus on our biologic understanding of OMBC and provide an update on current treatment strategies.

RECENT FINDINGS

The introduction of micro RNA expression profiling has advanced our understanding of the biologic underpinnings of OMBC. Although most of the data regarding treatment have come from retrospective studies, there are now prospective randomized trials reporting progression-free survival and overall survival improvements with stereotactic ablative radiotherapy (SABR). Ongoing studies designed to evaluate addition of SABR as well as other novel agents will further develop this field and provide new treatment options. A "cure" for OMBC remains elusive. With further basic research coupled with novel prospective trials, patients will hopefully enjoy increased progression-free survival and overall survival, and ideally a delay to more toxic systemic therapy.

The genetic script of metastasis

Metastasis is a pivotal event that changes the course of cancers from benign and treatable to malignant and difficult to treat, resulting in the demise of patients. Understanding the genetic control of metastasis is thus crucial to develop efficient and sustainable targeted therapies. Here we discuss the alterations in epigenetic mechanisms, transcription, chromosomal instability, chromosome imprinting, non-coding RNAs, coding RNAs, mutant RNAs, enhancers, G-quadruplexes, and copy number variation to dissect the genetic control of metastasis. We conclude that the genetic control of metastasis is predominantly executed through epithelial to mesenchymal transition and evasion of cell death. We discuss how genetic regulatory mechanisms can be harnessed for therapeutic purposes to achieve sustainable control over cancer metastasis.

miRMap: Profiling 14q32 microRNA Expression and DNA Methylation Throughout the Human Vasculature

Aims: MicroRNAs are regulators of (patho)physiological functions with tissue-specific expression patterns. However, little is known about inter-vascular differences in microRNA expression between blood vessel types or vascular beds. Differences in microRNA expression could influence cardiovascular pathophysiology at specific sites in the vasculature. Therefore, we aimed to map expression profiles of vasoactive 14q32 microRNAs throughout the human vasculature, as well as expression of vasoactive target genes of the 14q32 microRNAs. Furthermore, we aimed to map the DNA methylation status of the 14q32 locus, which has been linked to cardiovascular disease. Methods and Results: We collected 109 samples from different blood vessels, dissected during general surgery. Expression of a representative set of 17 14q32 microRNAs was measured in each sample. All 17 microRNAs showed a unique expression pattern throughout the vasculature. 14q32 microRNA expression was highest in lower limb vessels and lowest in head and neck vessels. All 17 microRNAs were expressed more abundantly in arteries than in veins. Throughout the human vasculature, we observed trends toward an inverse correlation between expression levels of the 14q32 microRNAs and their vasoactive target genes. DNA methylation of the 3 Differentially Methylated Regions (DMRs) along the 14q32 locus did not associate with primary or mature microRNA expression. However, hyper-methylation in venous coronary artery bypass grafts compared to arterial bypass grafts was observed in the Intergenic-DMR and MEG3-DMR. In patients with end-stage peripheral arterial disease we found differential DNA methylation throughout all DMRs in their lower limb veins. These findings were confirmed in a mouse model for vein-graft disease in which we found regulated 14q32 DNA methylation during the active phase of vascular remodeling. In ischemic tissues of a murine hind limb ischemia model we observed an increase in DNA methylation associated with increased ischemia over time. Conclusions: We show that 14q32 microRNAs are abundantly expressed in the human vasculature and that expression differs significantly between different blood vessels. 14q32 DNA methylation also varies throughout the vasculature and is associated with vascular health, independently of microRNA levels. These findings could have important implications for future research and for future site-specific targeting of epigenetics-based therapeutics.