HMGA1-pseudogene expression is induced in human pituitary tumors

Pathological roles of miRNAs and pseudogene-derived lncRNAs in human cancers, and their comparison as prognosis/diagnosis biomarkers

This review examines and compares the diagnostic and prognostic capabilities of miRNAs and lncRNAs derived from pseudogenes in cancer patients. Additionally, it delves into their roles in cancer pathogenesis. Both miRNAs and pseudogene-derived lncRNAs have undergone thorough investigation as remarkably sensitive and specific cancer biomarkers, offering significant potential for cancer detection and monitoring. . Extensive research is essential to gain a complete understanding of the precise roles these non-coding RNAs play in cancer, allowing the development of novel targeted therapies and biomarkers for improved cancer detection and treatment approaches.

A pan-cancer analysis of pituitary tumor-transforming 3, pseudogene

BACKGROUND

Although evidence regarding pituitary tumor-transforming 3, pseudogene (PTTG3P) involvement in human cancers has been acquired via human and animal model-based molecular studies, there is a lack of pan-cancer analysis of this gene in human tumors.

METHODS

Tumor-causing effects of PTTG3P in 24 human tumors were explored using The Cancer Genome Atlas (TCGA) datasets from different bioinformatics databases and applying in silico tools such as The University of ALabama at Birmingham CANcer (UALCAN), Human Protein Atlas (HPA), Kaplan Meier (KM) plotter, cBioPortal, Search Tool for the Retrieval of Interacting Genes/Proteins (STRING), Cytoscape, Database for Annotation, Visualization, and Integrated Discovery (DAVID), Tumor IMmune Estimation Resource (TIMER), and Comparative Toxicogenomics Database (CTD). Then, via in vitro experiments, including RNA sequencing (RNA-seq) and targeted bisulfite sequencing (bisulfite-seq), expression and promoter methylation levels of PTTG3P were verified in cell lines.

RESULTS

The PTTG3P expression was overexpressed across 23 malignancies and its overexpression was further found significantly effecting the overall survival (OS) durations of the esophageal carcinoma (ESCA) and head and neck cancer (HNSC) patients. This important information helps us to understand that PTTG3P plays a significant role in the development and progression of ESCA and HNSC. As for PTTG3P functional mechanisms, this gene along with its other binding partners was significantly concentrated in "Oocyte meiosis", "Cell cycle", "Ubiquitin mediated proteolysis", and "Progesterone-mediated oocyte maturation". Moreover, ESCA and HNSC tissues having the higher expression of PTTG3P were found to have lower promoter methylation levels of PTTG3P and higher CD8+ T immune cells level. Additionally, PTTG3P expression-regulatory drugs were also explored in the current manuscript for designing appropriate treatment strategies for ESCA and HNSC with respect to PTTG3P expression.

CONCLUSION

Our pan-cancer based findings provided a comprehensive account of the oncogenic role and utilization of PTTG3P as a novel molecular biomarker of ESCA and HNSC.

High Mobility Group A1 (HMGA1): Structure, Biological Function, and Therapeutic Potential

High mobility group A1 (HMGA1) is a nonhistone chromatin structural protein characterized by no transcriptional activity. It mainly plays a regulatory role by modifying the structure of DNA. A large number of studies have confirmed that HMGA1 regulates genes related to tumours in the reproductive system, digestive system, urinary system and haematopoietic system. HMGA1 is rare in adult cells and increases in highly proliferative cells such as embryos. After being stimulated by external factors, it will produce effects through the Wnt/β-catenin, PI3K/Akt, Hippo and MEK/ERK pathways. In addition, HMGA1 also affects the ageing, apoptosis, autophagy and chemotherapy resistance of cancer cells, which are linked to tumorigenesis. In this review, we summarize the mechanisms of HMGA1 in cancer progression and discuss the potential clinical application of targeted HMGA1 therapy, indicating that targeted HMGA1 is of great significance in the diagnosis and treatment of malignancy.

Pseudogenes and Liquid Phase Separation in Epigenetic Expression

Pseudogenes have been considered as non-functional genes. However, peptides and long non-coding RNAs produced by pseudogenes are expressed in different tumors. Moreover, the dysregulation of pseudogenes is associated with cancer, and their expressions are higher in tumors compared to normal tissues. Recent studies show that pseudogenes can influence the liquid phase condensates formation. Liquid phase separation involves regulating different epigenetic stages, including transcription, chromatin organization, 3D DNA structure, splicing, and post-transcription modifications like m⁶A. Several membrane-less organelles, formed through the liquid phase separate, are also involved in the epigenetic regulation, and their defects are associated with cancer development. However, the association between pseudogenes and liquid phase separation remains unrevealed. The current study sought to investigate the relationship between pseudogenes and liquid phase separation in cancer development, as well as their therapeutic implications.

Critical role of the high mobility group A proteins in hematological malignancies

The high mobility group A (HMGA) protein family is composed of three non‐histone chromatin remodeling proteins that act as architectural transcriptional factors. Indeed, although HMGA proteins lack transcriptional activity per se, they bind the minor groove of DNA at AT‐rich sequences, and, interacting with the transcription machinery, are able to modify chromatin modeling, thus regulating the expression of several genes. HMGA proteins have been deeply involved in embryogenesis process, and a large volume of studies has pointed out their key role in human cancer. Here, we review the studies on the role of the HMGA proteins in human hematological malignancies: they are overexpressed in most of the cases and their expression correlates with a reduced survival. In some cases, such as in acute lymphoblastic leukemia and acute myelogenous leukemia, HMGA2 gene rearrangements have been also described. Finally, recent studies evidence a synergism between HMGA and EZH2 in diffuse B‐cell lymphomas, suggesting an innovative therapy for this disease based on the inhibition of the function of both these proteins.

Enhancing Gonadotrope Gene Expression Through Regulatory lncRNAs

The world of long non-coding RNAs (lncRNAs) has opened up massive new prospects in understanding the regulation of gene expression. Not only are there seemingly almost infinite numbers of lncRNAs in the mammalian cell, but they have highly diverse mechanisms of action. In the nucleus, some are chromatin-associated, transcribed from transcriptional enhancers (eRNAs) and/or direct changes in the epigenetic landscape with profound effects on gene expression. The pituitary gonadotrope is responsible for activation of reproduction through production and secretion of appropriate levels of the gonadotropic hormones. As such, it exemplifies a cell whose function is defined through changes in developmental and temporal patterns of gene expression, including those that are hormonally induced. Roles for diverse distal regulatory elements and eRNAs in gonadotrope biology have only just begun to emerge. Here, we will present an overview of the different kinds of lncRNAs that alter gene expression, and what is known about their roles in regulating some of the key gonadotrope genes. We will also review various screens that have detected differentially expressed pituitary lncRNAs associated with changes in reproductive state and those whose expression is found to play a role in gonadotrope-derived nonfunctioning pituitary adenomas. We hope to shed light on this exciting new field, emphasize the open questions, and encourage research to illuminate the roles of lncRNAs in various endocrine systems.

The HMGA1-pseudogene7 shows oncogenic activity in vivo

We have recently reported that transgenic mice overexpressing the HMGA1-pseudogene7 develop hematological neoplasia marked by monoclonal B-cell populations, and diagnosed as Diffuse Large B-cell Lymphoma. These findings prove the HMGA1-pseudogene7 oncogenic role in vivo.

Characterization of HMGA1P6 transgenic mouse embryonic fibroblasts

Latest studies have shown that deregulated pseudogene transcripts contribute to cancer working as competing endogenous RNAs. Our research group has recently demonstrated that the overexpression of two HMGA1 pseudogenes, HMGA1P6 and HMGA1P7, has a critical role in cancer progression. These pseudogenes work sustaining the expression of HMGA1 and other cancer-related genes. We generated a mouse model overexpressing HMGA1P6 to better study the HMGA1-pseudogene function in a more physiological context. Here, we show the proliferation rate and the susceptibility to senescence of mouse embryonic fibroblasts obtained from HMGA1P6-overexpressing mice to better characterize the HMGA1-pseudogene function. Indeed, our study reports that mouse embryonic fibroblasts (MEFs) derived from HMGA1P6 mice express higher HMGA1 mRNA and protein levels. Moreover, these cells grow faster and senesce later than wild-type sustaining the oncogenic role of ceRNA crosstalk mediated by HMGA1Ps.

HMGA and Cancer: A Review on Patent Literatures

BACKGROUND

The high mobility group A proteins modulate the transcription of numerous genes by interacting with transcription factors and/or altering the structure of chromatin. These proteins are involved in both benign and malignant neoplasias as a result of several pathways. A large amount of benign human mesenchymal tumors has rearrangements of HMGA genes. On the contrary, malignant tumors show unarranged HMGA overexpression that is frequently and causally related to neoplastic cell transformation. Here, we review the function of the HMGA proteins in human neoplastic disorders, the pathways by which they contribute to carcinogenesis and the new patents focused on targeting HMGA proteins.

OBJECTIVE

Current review was conducted to check the involvement of HMGA as a druggable target in cancer treatment.

METHODS

We reviewed the most recent patents focused on targeting HMGA in cancer treatment analyzing patent literature published during the last years, including the World Intellectual Property Organization (WIPO®), United States Patent Trademark Office (USPTO®), Espacenet®, and Google Patents.

RESULTS

HMGA proteins are intriguing targets for cancer therapy and are objects of different patents based on the use of DNA aptamers, inhibitors, oncolytic viruses, antisense molecules able to block their oncogenic functions.

CONCLUSION

Powerful strategies able to selectively interfere with HMGA expression and function could represent a helpful approach in the development of new anti-cancer therapies.

Complex Analysis of Retroposed Genes' Contribution to Human Genome, Proteome and Transcriptome

Gene duplication is a major driver of organismal evolution. One of the main mechanisms of gene duplications is retroposition, a process in which mRNA is first transcribed into DNA and then reintegrated into the genome. Most gene retrocopies are depleted of the regulatory regions. Nevertheless, examples of functional retrogenes are rapidly increasing. These functions come from the gain of new spatio-temporal expression patterns, imposed by the content of the genomic sequence surrounding inserted cDNA and/or by selectively advantageous mutations, which may lead to the switch from protein coding to regulatory RNA. As recent studies have shown, these genes may lead to new protein domain formation through fusion with other genes, new regulatory RNAs or other regulatory elements. We utilized existing data from high-throughput technologies to create a complex description of retrogenes functionality. Our analysis led to the identification of human retroposed genes that substantially contributed to transcriptome and proteome. These retrocopies demonstrated the potential to encode proteins or short peptides, act as cis- and trans- Natural Antisense Transcripts (NATs), regulate their progenitors’ expression by competing for the same microRNAs, and provide a sequence to lncRNA and novel exons to existing protein-coding genes. Our study also revealed that retrocopies, similarly to retrotransposons, may act as recombination hot spots. To our best knowledge this is the first complex analysis of these functions of retrocopies.

HMGA1-pseudogene7 transgenic mice develop B cell lymphomas

We have recently identified and characterized two pseudogenes (HMGA1P6 and HMGA1P7) of the HMGA1 gene, which has a critical role in malignant cell transformation and cancer progression. HMGA1P6 and HMGAP17 act as microRNA decoy for HMGA1 and other cancer-related genes upregulating their protein levels. We have previously shown that they are upregulated in several human carcinomas, and their expression positively correlates with a poor prognosis and an advanced cancer stage. To evaluate in vivo oncogenic activity of HMGA1 pseudogenes, we have generated a HMGA1P7 transgenic mouse line overexpressing this pseudogene. By a mean age of 12 months, about 50% of the transgenic mice developed splenomegaly and accumulation of lymphoid cells in several body compartments. For these mice FACS and immunohistochemical analyses suggested the diagnosis of B-cell lymphoma that was further supported by clonality analyses and RNA expression profile of the pathological tissues of the HMGA1P7 transgenic tissues. Therefore, these results clearly demonstrate the oncogenic activity of HMGA1 pseudogenes in vivo.

RPSAP52 lncRNA Inhibits p21Waf1/CIP Expression by Interacting With the RNA Binding Protein HuR

Long noncoding RNAs have been recently demonstrated to have an important role in fundamental biological processes, and their deregulated expression has been found in several human neoplasias. Our group has recently reported a drastic overexpression of the long noncoding RNA (lncRNA) RPSAP52 (ribosomal protein SA pseudogene 52) in pituitary adenomas. We have shown that this lncRNA increased cell proliferation by upregulating the expression of the chromatinic proteins HMGA1 and HMGA2, functioning as a competing endogenous RNA (ceRNA) through competitively binding to microRNA-15a (miR-15a), miR-15b, and miR-16. The aim of this work was to identify further mechanisms by which RPSAP52 overexpression could contribute to the development of pituitary adenomas. We investigated the involvement of RPSAP52 in the modulation of the expression of cell cycle-related genes, such as p21Waf1/CIP, whose deregulation plays a critical role in pituitary cell transformation. We report that RPSAP52, interacting with the RNA binding protein HuR (human antigen R), favors the delocalization of miR-15a, miR-15b, and miR-16 on the cyclin-dependent kinase inhibitor p21Waf1/CIP1 that, accordingly, results in downregulation in pituitary adenomas. A RNA immunoprecipitation sequencing (RIPseq) analysis performed on cells overexpressing RPSAP52 identified 40 messenger RNAs (mRNAs) enriched in Argonaute 2 (AGO2) immunoprecipitated samples. Among them, we focused on GAS8 (growth arrest-specific protein 8) gene. Consistently, GAS8 expression was downregulated in all the analyzed pituitary adenomas with respect to normal pituitary and in RPSAP52-overepressing cells, supporting the role of RPSAP52 in addressing genes involved in growth inhibition and cell cycle arrest to miRNA-induced degradation. This study unveils another RPSAP52-mediated molecular mechanism in pituitary tumorigenesis.

Further insights into testicular germ cell tumor oncogenesis: potential therapeutic targets

Introduction: Testicular germ cell tumors (TGCTs) are the most common neoplasia in the young male population, and the incidence has been constantly increasing in many parts of the world. These tumors are classified into seminomas and non-seminomas, and those divided, in turn, into yolk sac tumors, embryonal cell carcinomas, choriocarcinomas, and teratomas. Although therapeutic approaches have improved, approximately 25% of the patients relapse or, in a small number of cases, show platinum-resistant disease.Areas covered: We review several molecular targets that have recently emerged as powerful tools for both diagnosis and therapy of TGCTs. Moreover, we reviewed the most frequent deregulated pathways involved in TGCT tumorigenesis, reporting drugs that may emerge as novel therapeutic agents.Expert opinion: TGCT treatment is mainly based on platinum-derivative therapy with high cure rates. However, in the refractory patients, there are few alternative treatments. Thus, different pharmacological approaches have to be thoroughly investigated to shed new light on TGCT pathogenesis and treatment.

MYC-regulated pseudogene HMGA1P6 promotes ovarian cancer malignancy via augmenting the oncogenic HMGA1/2

Pseudogenes have long been considered as nonfunctional genomic sequences. Recent studies have shown that they can potentially regulate the expression of protein-coding genes and are dysregulated in diseases including cancer. However, the potential roles of pseudogenes in ovarian cancer have not been well studied. Here we characterized the pseudogene expression profile in HGSOC (high-grade serous ovarian carcinoma) by microarray. We identified 577 dysregulated pseudogenes and most of them were up-regulated (538 of 577). HMGA1P6 (High mobility group AT-hook 1 pseudogene 6) was one of the overexpressed pseudogenes and its expression was inversely correlated with patient survival. Mechanistically, HMGA1P6 promoted ovarian cancer cell malignancy by acting as a ceRNA (competitive endogenous RNA) that led to enhanced HMGA1 and HMGA2 expression. Importantly, HMGA1P6 was transcriptionally activated by oncogene MYC in ovarian cancer. Our findings reveal that MYC may contribute to oncogenesis through transcriptional regulation of pseudogene HMGA1P6 in ovarian cancer.

Pseudogene-Derived lncRNAs and Their miRNA Sponging Mechanism in Human Cancer

Pseudogenes, abundant in the human genome, are traditionally considered as non-functional “junk genes.” However, recent studies have revealed that pseudogenes act as key regulators at DNA, RNA or protein level in diverse human disorders (including cancer), among which pseudogene-derived long non-coding RNA (lncRNA) transcripts are extensively investigated and has been reported to be frequently dysregulated in various types of human cancer. Growing evidence demonstrates that pseudogene-derived lncRNAs play important roles in cancer initiation and progression by serving as competing endogenous RNAs (ceRNAs) through competitively binding to shared microRNAs (miRNAs), thus affecting both their cognate genes and unrelated genes. Herein, we retrospect those current findings about expression, functions and potential ceRNA mechanisms of pseudogene-derived lncRNAs in human cancer, which may provide us with some crucial clues in developing potential targets for cancer therapy in the future.

High Mobility Group A (HMGA): Chromatin Nodes Controlled by a Knotty miRNA Network

High mobility group A (HMGA) proteins are oncofoetal chromatin architectural factors that are widely involved in regulating gene expression. These proteins are unique, because they are highly expressed in embryonic and cancer cells, where they play a relevant role in cell proliferation, stemness, and the acquisition of aggressive tumour traits, i.e., motility, invasiveness, and metastatic properties. The HMGA protein expression levels and activities are controlled by a connected set of events at the transcriptional, post-transcriptional, and post-translational levels. In fact, microRNA (miRNA)-mediated RNA stability is the most-studied mechanism of HMGA protein expression modulation. In this review, we contribute to a comprehensive overview of HMGA-targeting miRNAs; we provide detailed information regarding HMGA gene structural organization and a comprehensive evaluation and description of HMGA-targeting miRNAs, while focusing on those that are widely involved in HMGA regulation; and, we aim to offer insights into HMGA-miRNA mutual cross-talk from a functional and cancer-related perspective, highlighting possible clinical implications.

Re-recognition of pseudogenes: From molecular to clinical applications

Pseudogenes were initially regarded as "nonfunctional" genomic elements that did not have protein-coding abilities due to several endogenous inactivating mutations. Although pseudogenes are widely expressed in prokaryotes and eukaryotes, for decades, they have been largely ignored and classified as gene "junk" or "relics". With the widespread availability of high-throughput sequencing analysis, especially omics technologies, knowledge concerning pseudogenes has substantially increased. Pseudogenes are evolutionarily conserved and derive primarily from a mutation or retrotransposon, conferring the pseudogene with a "gene repository" role to store and expand genetic information. In contrast to previous notions, pseudogenes have a variety of functions at the DNA, RNA and protein levels for broadly participating in gene regulation to influence the development and progression of certain diseases, especially cancer. Indeed, some pseudogenes have been proven to encode proteins, strongly contradicting their "trash" identification, and have been confirmed to have tissue-specific and disease subtype-specific expression, indicating their own value in disease diagnosis. Moreover, pseudogenes have been correlated with the life expectancy of patients and exhibit great potential for future use in disease treatment, suggesting that they are promising biomarkers and therapeutic targets for clinical applications. In this review, we summarize the natural properties, functions, disease involvement and clinical value of pseudogenes. Although our knowledge of pseudogenes remains nascent, this field deserves more attention and deeper exploration.

The Prominent Role of HMGA Proteins in the Early Management of Gastrointestinal Cancers

GI tumors represent a heterogeneous group of neoplasms concerning their natural history and molecular alterations harbored. Nevertheless, these tumors share very high incidence and mortality rates worldwide and patients' poor prognosis. Therefore, the identification of specific biomarkers could increase the development of personalized medicine, in order to improve GI cancer management. In this sense, HMGA family members (HMGA1 and HMGA2) comprise an important group of genes involved in the genesis and progression of malignant tumors. Additionally, it has also been reported that HMGA1 and HMGA2 display an important role in the detection and progression of GI tumors. In this way, HMGA family members could be used as reliable biomarkers able to efficiently track not only the tumor per se but also the main risk conditions related with their development of GI cancers in the future. Finally, it shall be a promising option to revert the current scenario, once HMGA genes and proteins could represent a convergence point in the complex landscape of GI tumors.

Emerging Role of USP8, HMGA, and Non-Coding RNAs in Pituitary Tumorigenesis

Two novel molecular mechanisms with a driver role in pituitary tumorigenesis have been recently identified. They are (a) mutations in the Ubiquitin-Specific Protease 8 (USP8) gene in corticotroph tumors and (b) overexpression of the HMGA1 and HMGA2 genes in most of the pituitary tumors. Moreover, deregulated expression of the non-coding RNAs has been very frequently observed in this neoplasia. The aim of this review is to better elucidate the role, the mechanisms, and the possible clinical impact of these novel alterations in the development of pituitary neoplasia.

LncRNA XIST depletion prevents cancer progression in invasive pituitary neuroendocrine tumor by inhibiting bFGF via upregulation of microRNA-424-5p

Background

Long noncoding RNAs (lncRNAs) are vital mediators in human cancers including pituitary neuroendocrine tumor (PitNET) and could function as competing endogenous RNAs (ceRNAs) of microRNAs (miRNAs). The main objective of this study is to identify effect of lncRNA X-inactive specific transcript (XIST) and microRNA-424-5p (miR-424-5p) on PitNET.

Methods

Microarray analysis was employed to identify the PitNET-related differentially expressed lncRNAs. PitNET tissues, including both invasive and non-invasive subtypes in parallel with normal pituitary tissues were collected for the determination of the expression of XIST, miR-424-5p and basic fibroblast growth factor (bFGF) and the interaction among them. Subsequently, the expression of XIST, miR-424-5p and bFGF in PitNET cells was altered to elucidate their biological significance in the aspects of proliferation, migration, invasion, and the apoptosis.

Results

Both XIST and bFGF exhibited high expression, but miR-424-5p had a low expression in invasive PitNET tissues as compared to non-invasive PitNET normal pituitary tissues. Additionally, XIST competitively bound to miR-424-5p to elevate the expression of bFGF. Furthermore, depleted XIST or bFGF, or elevated miR-424-5p was revealed to suppress the proliferation, migration, invasion, and promote cell cycle arrest and apoptosis of invasive PitNET cells. miR-424-5p repressed the proliferation, migration, invasion of invasive PitNET cells by targeting bFGF.

Conclusion

In conclusion, the fundamental findings of the present study suggested that the functional suppression of XIST downregulated bFGF to inhibit the development of PitNET by increasing miR-424-5p expression, proposing XIST as a novel therapeutic target for PitNET.

Differential Expression of HMGA1 and HMGA2 in pituitary neuroendocrine tumors

Defining biomarkers for invasive pituitary neuroendocrine tumors (PitNETs) is highly desirable. The high mobility group A (HMGA) proteins are among the most widely expressed cancer-associated proteins. Indeed, their overexpression is a frequent feature of human malignancies, including PitNETs. We show that nonfunctioning PitNETs (NF-PitNETs) express significantly higher levels of HMGA1 than somatotropinomas (GHs) and corticotropinomas (ACTHs). Furthermore, HMGA2 expression was detected only in NF-PitNETs and was significantly higher in larger tumors than in smaller tumors. HMGA expression analysis generally focuses on nuclear staining. Here, cytoplasmic HMGA staining was also found. PitNETs displayed strong nuclear HMGA1 and strong cytoplasmic HMGA2 immunoreactivity. Interestingly, the HMGA1 and HMGA2 nuclear expression levels were significantly higher in invasive adenomas than in noninvasive adenomas. The highest levels of nuclear HMGA2 were found in GHs. In conclusion, we show that overexpression of nuclear HMGA proteins could be a potential biomarker of invasive PitNETs, particularly HMGA2 for GHs. HMGA2 might be a reliable biomarker for NF-PitNETs.

Overexpression of HMGA1 Figures as a Potential Prognostic Factor in Endometrioid Endometrial Carcinoma (EEC)

Endometrioid endometrial carcinomas (EEC) are the most common malignant gynecologic tumors. Despite the increase in EEC molecular knowledge, the identification of new biomarkers involved in disease's development and/or progression would represent an improvement in its course. High-mobility group A protein (HMGA) family members are frequently overexpressed in a wide range of malignancies, correlating with a poor prognosis. Thus, the aim of this study was to analyze HMGA1 and HMGA2 expression pattern and their potential role as EEC biomarkers. HMGA1 and HMGA2 expression was initially evaluated in a series of 46 EEC tumors (stages IA to IV), and the findings were then validated in The Cancer Genome Atlas (TCGA) EEC cohort, comprising 381 EEC tumors (stages IA to IV). Our results reveal that HMGA1 and HMGA2 mRNA and protein are overexpressed in ECC, but only HMGA1 expression is associated with increased histological grade and tumor size. Moreover, HMGA1 but not HMGA2 overexpression was identified as a negative prognostic factor to EEC patients. Finally, a positive correlation between expression of HMGA1 pseudogenes-HMGA1-P6 and HMGA1-P7-and HMGA1 itself was detected, suggesting HMGA1 pseudogenes may play a role in HMGA1 expression regulation in EEC. Thus, these results indicate that HMGA1 overexpression possesses a potential role as a prognostic biomarker for EEC.

Characteristics of the competition among RNAs for the binding of shared miRNAs

Competing endogenous RNAs (ceRNAs) are RNAs that share common miRNA binding sites and compete with each other for the miRNA association at these sites. The observation of this phenomenon in the cells altered the view of the miRNA target RNAs from molecules that are passively controlled by miRNAs to molecules that also modulate the miRNAs activity. In this review, we build a general profile of ceRNAS characteristics in order to facilitate ceRNAs identification by researchers. The information summarized here contains an actualized list of previously reported ceRNAs and classes of RNAs that can participate in this type of interaction, the expression behavior and characteristics of ceRNAs and miRNAs in the context of competition, the influence of the shared MREs/miRNAs numbers and the miRNA binding strength on the competition, reports on competition between RNAs in different subcellular localizations and the concept that ceRNAs may form a huge regulatory network in the cell.

High Expression of Pseudogene PTTG3P Indicates a Poor Prognosis in Human Breast Cancer

Pseudogenes play pivotal roles in tumorigenesis. Previous studies have suggested that pituitary tumor-transforming 3, pseudogene (PTTG3P), serves as an oncogene in human cancers. However, its expression pattern, biological function, and underlying mechanism in breast cancer remain unknown. In this study, we demonstrated an elevated expression of PTTG3P in breast cancer and discovered that PTTG3P expression correlated negatively with estrogen receptor (ER) and progesterone receptor (PR) status, but linked positively to basal-like status, triple-negative breast cancer status, Nottingham prognostic index (NPI), and Scarff-Bloom-Richardson grade. High expression of PTTG3P was also found to be associated with a poor prognosis of breast cancer. To explore the potential mechanisms of PTTG3P, a PTTG3P-microRNA (miRNA)-mRNA regulatory network was established. Co-expressed genes of PTTG3P were also obtained. Enrichment analysis for these co-expressed genes revealed that they were significantly enriched in mitotic nuclear division and cell cycle. Subsequent research on mechanism of PTTG3P indicated that its expression correlated positively with PTTG1 expression. However, no significant expression correlation between PTTG3P and PTTG2 was observed. Taken together, our findings suggest that increased expression of pseudogene PTTG3P may be used as a promising prognostic biomarker and novel therapeutic target for breast cancer.

New Anti-Cancer Strategies in Testicular Germ Cell Tumors

Methods:

Bibliographic data from peer-reviewed research, patent and clinical trial literature, and around eighty papers and patents have been included in this review.

Results:

Our study reveals that several biomarkers are usefully utilized to discriminate among different histotypes. Moreover, we found new patents regarding testicular germ cell tumor treatments such as the expression of claudin 6, monoclonal antibody (Brentuximab Vedotin), immune checkpoint blockade (ICB) with the FDA-approved drugs pembrolizumab and nivolumab or the oncolytic virus Pelareorep, the combination of selective inhibitors of Aurora kinase.

Conclusion:

Finally, the pathogenesis of testicular germ cell tumor needs to be deeply understood so that it will improve data on stem cells, tumorigenesis and disease tumor management by more selective treatment.

HMGA1 in cancer: Cancer classification by location

The high mobility group A1 (HMGA1) gene plays an important role in numerous malignant cancers. HMGA1 is an oncofoetal gene, and we have a certain understanding of the biological function of HMGA1 based on its activities in various neoplasms. As an architectural transcription factor, HMGA1 remodels the chromatin structure and promotes the interaction between transcriptional regulatory proteins and DNA in different cancers. Through analysis of the molecular mechanism of HMGA1 and clinical studies, emerging evidence indicates that HMGA1 promotes the occurrence and metastasis of cancer. Within a similar location or the same genetic background, the function and role of HMGA1 may have certain similarities. In this paper, to characterize HMGA1 comprehensively, research on various types of tumours is discussed to further understanding of the function and mechanism of HMGA1. The findings provide a more reliable basis for classifying HMGA1 function according to the tumour location. In this review, we summarize recent studies related to HMGA1, including its structure and oncogenic properties, its major functions in each cancer, its upstream and downstream regulation associated with the tumourigenesis and metastasis of cancer, and its potential as a biomarker for clinical diagnosis of cancer.

The Epigenomics of Pituitary Adenoma

Background: The vast majority of pituitary tumors are benign and behave accordingly; however, a fraction are invasive and are more aggressive, with a very small fraction being frankly malignant. The cellular pathways that drive transformation in pituitary neoplasms are poorly characterized, and current classification methods are not reliable correlates of clinical behavior. Novel techniques in epigenetics, the study of alterations in gene expression without changes to the genetic code, provide a new dimension to characterize tumors, and may hold implications for prognostication and management. Methods: We conducted a review of primary epigenetic studies of pituitary tumors with a focus on histone modification, DNA methylation, and transcript modification. Results: High levels of methylation have been identified in invasive and large pituitary tumors. DNA methyltransferase overexpression has been detected in pituitary tumors, especially in macroadenomas. Methylation differences at CpG sites in promoter regions may distinguish several types of tumors from normal pituitary tissue. Histone modifications have been linked to increased p53 expression and longer progression-free survival in pituitary tumors; sirtuins are expressed at higher values in GH-expressing compared to nonfunctional adenomas and correlate inversely with size in somatotrophs. Upregulation in citrullinating enzymes may be an early pathogenic marker of prolactinomas. Numerous genes involved with cell growth and signaling show altered methylation status for pituitary tumors, including cell cycle regulators, components of signal transduction pathways, apoptotic regulators, and pituitary developmental signals. Conclusions: The limited clinical predictive capacity of the current pituitary tumor classification system suggests that tumor subclasses likely remain to be discovered. Ongoing epigenetic studies could provide a basis for adding methylation and/or acetylation screening to standard pituitary tumor workups. Identifying robust correlations between tumor epigenetics and corresponding histological, radiographic, and clinical course information could ultimately inform clinical decision-making.

miR-16 regulates proliferation and apoptosis of pituitary adenoma cells by inhibiting HMGA2

Previous studies have revealed that elevated expression of high mobility group A2 (HMGA2) is closely associated with the occurrence of pituitary adenomas (PAs). The expression of microRNA (miR)-16 is deregulated in PA tissues. Bioinformatics analysis has demonstrated that there is a complementary region between seed region of miR-16 and 3'-untranslated region (3'-UTR) of HMGA2 gene. In the present study, it was investigated whether miR-16 may regulate the expression of HMGA2 and whether it is involved in the pathogenesis of PAs. A total of 52 patients with PAs were recruited. Normal brain tissues obtained from 12 patients with traumatic brain injury were used as controls. The association between miR-16 and HMGA2 was validated using dual-luciferase reporter gene assay. HP75 cells were cultured in vitro and divided into the following groups: miR control, miR-16 mimic, small interfering RNA (si)-negative control, si-HMGA2 and miR-16 mimic+si-HMGA2 groups. The expression of miR-16 and HMGA2 in HP75 cells was determined using qRT-PCR and western blot. Cell proliferation was detected using the Cell Counting Kit-8 assay and apoptosis was detected using the TdT-UTP nick end labeling assay. Compared with normal pituitary tissues, the expression of miR-16 in PA tissues was significantly decreased, while the mRNA and protein levels of HMGA2 were significantly increased. miR-16 targeted the 3'-UTR of HMGA2 gene and regulated the expression of HMGA2. Transfection with siRNAs targeting HMGA2 and/or miR-16 mimics inhibited the expression of HMGA2 and the proliferative ability of HP75 cells, whereas it increased apoptosis of HP75 cells. The downregulation of miR-16 and upregulation of HMGA2 were involved in the pathogenesis of PAs. Thus, it is hypothesized that miR-16 inhibited the proliferation and promoted apoptosis of HP75 cells by inhibiting HMGA2 expression.

Competing endogenous RNA (ceRNA) cross talk and language in ceRNA regulatory networks: A new look at hallmarks of breast cancer

Breast cancer (BC) is the most frequently occurring malignancy in women worldwide. Despite the substantial advancement in understanding the molecular mechanisms and management of BC, it remains the leading cause of cancer death in women. One of the main reasons for this obstacle is that we have not been able to find the Achilles heel for the BC as a highly heterogeneous disease. Accumulating evidence has revealed that noncoding RNAs (ncRNAs), play key roles in the development of BC; however, the involving of complex regulatory interactions between the different varieties of ncRNAs in the development of this cancer has been poorly understood. In the recent years, the newly discovered mechanism in the RNA world is "competing endogenous RNA (ceRNA)" which proposes regulatory dialogues between different RNAs, including long ncRNAs (lncRNAs), microRNAs (miRNAs), transcribed pseudogenes, and circular RNAs (circRNAs). In the latest BC research, various studies have revealed that dysregulation of several ceRNA networks (ceRNETs) between these ncRNAs has fundamental roles in establishing the hallmarks of BC development. And it is thought that such a discovery could open a new window for a better understanding of the hidden aspects of breast tumors. Besides, it probably can provide new biomarkers and potential efficient therapeutic targets for BC. This review will discuss the existing body of knowledge regarding the key functions of ceRNETs and then highlights the emerging roles of some recently discovered ceRNETs in several hallmarks of BC. Moreover, we propose for the first time the "ceRnome" as a new term in the present article for RNA research.

Characterization of inflammatory infiltrate of ulcerative dermatitis in C57BL/6NCrl-Tg(HMGA1P6)1Pg mice

Ulcerative dermatitis (UD) is an idiopathic, spontaneous and progressive disease typically affecting C57BL/6 aged mice with an unknown aetiopathogenesis. For this study, we evaluated 25 cases of UD in C57BL/6NCrl-Tg(HMGA1P6)1Pg mice. Formalin-fixed, paraffin-embedded skin samples were submitted to morphological investigations. Immunohistochemical analysis was performed to characterize and quantify inflammatory cells using CD3, CD45/B220, CD4, CD8 and IL-17 antibodies. Mast cell-bound IgE was investigated by immunofluorescence, whereas serum and cryopreserved skin samples were collected for molecular analysis. Student's t-test (two-tailed) was performed to assess significant differences between the two groups. Affected skin showed extensive areas of ulceration and diffuse, severe and mixed inflammatory infiltrates. No relevant changes were observed in control mice. Immunohistochemical analysis showed a predominant CD3 + CD4 + leukocyte population with fewer CD45/B220 and IL-17 immunolabelled cells and mast cell-bound IgE. Increases in TNFα, IL-1β and Il-6 mRNA expression were observed in the skin of affected animals compared to controls. Serum TNFα and IL-6 did not vary between affected and control mice. Inflammatory infiltrates and cytokine expression were consistent with both Th2/IgE and Th17 differentiation, a typical pattern of a type I hypersensitivity reaction. Overall, our data suggest an allergic-based aetiopathogenesis of UD in C57BL/6NCrl-Tg(HMGA1P6)1Pg mice.

SLC6A1-miR133a-CDX2 loop regulates SK-OV-3 ovarian cancer cell proliferation, migration and invasion

The present study assessed the expression of solute carrier 6 member 1 (SLC6A1) in ovarian cancer (OC) tissues and evaluated the effect of silencing SLC6A1 or caudal type homeobox 2 (CDX2) on the proliferation, migration, and invasion of SK-OV-3 OC cells. The levels of caudal type homeobox 2 (CDX2) and SLC6A1 mRNA were also examined in OC SK-OV-3, OVCAR3 and A2780 cell lines. The mRNA levels of CDX2 and SLC6A1 in SK-OV-3 OC cells were assessed following transection with microRNA (miR) 133a mimics; the mRNA and protein levels of SLC6A1 were determined following the silencing of CDX2, and the mRNA expression of CDX2 was gauged following the silencing of SLC6A1. A luciferase reporter assay was performed to assess the effect of miR133a on the CDX2 and SLC6A1 3′-untranslated regions (3′UTRs). The proliferation, migration and invasion rate of SK-OV-3 cells were then examined following the silencing of CDX2 or SLC6A1. The expression of SLC6A1 was increased in OC compared with adjacent tissue. The expression of CDX2 and SLC6A1 in SK-OV-3 and OVCAR3 cells was increased compared with A2780 cells (P<0.05). The level of CDX2 and SLC6A1 mRNA in SK-OV-3 cells decreased when the cells were transected with the miR133a mimics, compared with a negative control (P<0.05). Transfection with the miR133a mimics significantly reduced the luciferase activity of reporter plasmids with the SLC6A1 or CDX2 3′UTRs (P<0.05). The mRNA level of CDX2 was decreased subsequent to the silencing of SLC6A1; the mRNA and protein level of SLC6A1 were decreased when CDX2 was silenced (P<0.05). The proliferation, migration, and invasion of SK-OV-3 cells were significantly reduced following the silencing of CDX2 or SLC6A1 (P<0.05). CDX2 may therefore be inferred to promote the proliferation, migration and invasion in SK-OV-3 OC cells, acting as a competing endogenous RNA.

HMGA2, but not HMGA1, is overexpressed in human larynx carcinomas

AIMS

Malignant tumours from the upper aerodigestive tract are grouped collectively in the class of head and neck squamous cell carcinoma (HNSCC). The head and neck tumours were responsible for more than 500 000 cancer cases in 2012, accounting for the sixth highest incidence rate and mortality worldwide among all tumour types. Laryngeal squamous cell carcinoma (LSCC) possesses the second highest incidence rate among all HNSCC. Despite significant advances in surgery and radiotherapy during the last few decades, no treatment has been shown to achieve a satisfactory therapeutic outcome and the mortality rate of LSCC is still high, with a 5-year survival rate of 64%. Therefore, further investigations are required to identify the pathogenesis of LSCC.

METHODS AND RESULTS

In order to search for new LSCC biomarkers, we have analysed the expression of the HMGA family members, HMGA1 and HMGA2, by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. HMGA proteins are usually absent in the healthy adult tissues. In contrast, their constitutive expression is a feature of several neoplasias, being associated with a highly malignant phenotype and reduced survival. Here, we report HMGA2 overexpression in larynx carcinomas. Conversely, HMGA1 does not show any differences in its expression between normal and carcinoma tissues. Interestingly, HMGA2 overexpression appears associated with that of two HMGA1-pseudogenes, HMGA1P6 and HMGA1P7, acting as a sponge for HMGA1- and HMGA2-targeting microRNAs and involved in several human cancers.

CONCLUSIONS

Therefore, HMGA2 overexpression appears to be a strong feature of larynx carcinoma, supporting its detection as a valid tool for the diagnosis of these malignancies.

IL‑17 induces NSCLC A549 cell proliferation via the upregulation of HMGA1, resulting in an increased cyclin D1 expression

Non-small cell lung cancer (NSCLC) is considered to be an inflammation-associated carcinoma. Although interleukin‑17 (IL‑17) production contributes to the proliferation and growth of NSCLC, the mechanisms underlying IL‑17-induced NSCLC cell proliferation have not been fully elucidated. In the present study, by using ELISA and immunohistochemical analyses, we first found that the expression levels of IL‑17, IL‑17 receptor (IL‑17R), high-mobility group A1 (HMGA1) and cyclin D1 were elevated in the samples of patients with NSCLC. Subsequently, by RT-qPCR, western blot analysis and cell proliferation assay in vitro, we revealed that stimulation with recombinant human IL‑17 (namely IL‑17A) markedly induced the expression of HMGA1 and cyclin D1 in the A549 cells (a human lung adenocarcinoma cell line) and promoted cell proliferation. Furthermore, luciferase reporter and ChIP assays confirmed that upregulated HMGA1 directly bound to the cyclin D1 gene promoter and activated its transcription. Notably, the response element of HMGA1 binding to the cyclin D1 promoter was disclosed for the first time, at least to the best of our knowledge. Taken together, our findings indicate that the IL‑17/HMGA1/cyclin D1 axis plays an important role in NSCLC cell proliferation and may provide new insight into NSCLC pathogenesis and may thus aid in the development of novel therapeutic targets for NSCLC.

Competing endogenous RNA networks in human cancer: hypothesis, validation, and perspectives

Non-coding RNAs represent a majority of the human transcriptome. However, less is known about the functions and regulatory mechanisms of most non-coding species. Moreover, little is known about the potential non-coding functions of coding RNAs. The competing endogenous RNAs (ceRNAs) hypothesis is proposed recently. This hypothesis describes potential communication networks among all transcript RNA species mediated by miRNAs and miRNA-recognizing elements (MREs) within RNA transcripts. Here we review the evolution of the ceRNA hypothesis, summarize the validation experiments and discusses the significance and perspectives of this hypothesis in human cancer.

HMGA1-pseudogenes and cancer

Pseudogenes are DNA sequences with high homology to the corresponding functional gene, but, because of the accumulation of various mutations, they have lost their initial functions to code for proteins. Consequently, pseudogenes have been considered until few years ago dysfunctional relatives of the corresponding ancestral genes, and then useless in the course of genome evolution. However, several studies have recently established that pseudogenes are owners of key biological functions. Indeed, some pseudogenes control the expression of functional genes by competitively binding to the miRNAs, some of them generate small interference RNAs to negatively modulate the expression of functional genes, and some of them even encode functional mutated proteins. Here, we concentrate our attention on the pseudogenes of the HMGA1 gene, that codes for the HMGA1a and HMGA1b proteins having a critical role in development and cancer progression. In this review, we analyze the family of HMGA1 pseudogenes through three aspects: classification, characterization, and their possible function and involvement in cancer.

The HMGA1 Pseudogene 7 Induces miR-483 and miR-675 Upregulation by Activating Egr1 through a ceRNA Mechanism

Several studies have established that pseudogene mRNAs can work as competing endogenous RNAs and, when deregulated, play a key role in the onset of human neoplasias. Recently, we have isolated two HMGA1 pseudogenes, HMGA1P6 and HMGA1P7. These pseudogenes have a critical role in cancer progression, acting as micro RNA (miRNA) sponges for HMGA1 and other cancer-related genes. HMGA1 pseudogenes were found overexpressed in several human carcinomas, and their expression levels positively correlate with an advanced cancer stage and a poor prognosis. In order to investigate the molecular alterations following HMGA1 pseudogene 7 overexpression, we carried out miRNA sequencing analysis on HMGA1P7 overexpressing mouse embryonic fibroblasts. Intriguingly, the most upregulated miRNAs were miR-483 and miR-675 that have been described as key regulators in cancer progression. Here, we report that HMGA1P7 upregulates miR-483 and miR-675 through a competing endogenous RNA mechanism with Egr1, a transcriptional factor that positively regulates miR-483 and miR-675 expression.

microRNA inhibitors: Natural and artificial sequestration of microRNA

MicroRNA (miRNAs) is post-transcriptional regulator of mRNA. However, the prevalence and activity of miRNA are regulated by other regulators. miRNA inhibitors are natural or artificial RNA transcripts that sequestrate miRNAs and decrease or even eliminate miRNA activity. Competing endogenous RNAs (ceRNAs) are natural and intracellular miRNA inhibitors that compete to bind to shared miRNA recognition elements (MREs) to decrease microRNA availability and relieve the repression of target RNAs. In recent years, studies have revealed that ceRNA crosstalk is involved in many pathophysiological processes and adds a new dimension to miRNA regulation. Artificial miRNA inhibitors are RNA transcripts that are synthesized via chemical and genetic methods. Artificial miRNA inhibitors can be used in miRNA loss-of-function research and gene therapies for certain diseases. In this review, we summarize the recent advances in the two different types of miRNA inhibitors.

Pseudogenes regulate parental gene expression via ceRNA network

The concept of competitive endogenous RNA (ceRNA) was first proposed by Salmena and colleagues. Evidence suggests that pseudogene RNAs can act as a 'sponge' through competitive binding of common miRNA, releasing or attenuating repression through sequestering miRNAs away from parental mRNA. In theory, ceRNAs refer to all transcripts such as mRNA, tRNA, rRNA, long non-coding RNA, pseudogene RNA and circular RNA, because all of them may become the targets of miRNA depending on spatiotemporal situation. As binding of miRNA to the target RNA is not 100% complementary, it is possible that one miRNA can bind to multiple target RNAs and vice versa. All RNAs crosstalk through competitively binding to miRNAvia miRNA response elements (MREs) contained within the RNA sequences, thus forming a complex regulatory network. The ratio of a subset of miRNAs to the corresponding number of MREs determines repression strength on a given mRNA translation or stability. An increase in pseudogene RNA level can sequester miRNA and release repression on the parental gene, leading to an increase in parental gene expression. A massive number of transcripts constitute a complicated network that regulates each other through this proposed mechanism, though some regulatory significance may be mild or even undetectable. It is possible that the regulation of gene and pseudogene expression occurring in this manor involves all RNAs bearing common MREs. In this review, we will primarily discuss how pseudogene transcripts regulate expression of parental genes via ceRNA network and biological significance of regulation.

HMGA1P7-pseudogene regulates H19 and Igf2 expression by a competitive endogenous RNA mechanism

Recent studies have revealed that pseudogene transcripts can function as competing endogenous RNAs, and thereby can also contribute to cancer when dysregulated. We have recently identified two pseudogenes, HMGA1P6 and HMGA1P7 for the HMGA1 gene whose overexpression has a critical role in cancer progression. These pseudogenes work as competitive endogenous RNA decoys for HMGA1 and other cancer related genes suggesting their role in carcinogenesis. Looking for new HMGA1 pseudogene ceRNAs, we performed RNA sequencing technology on mouse embryonic fibroblasts deriving from transgenic mice overexpressing HMGA1P7. Here, we report that HMGA1P7 mRNA sustains the H19 and Igf2 overexpression by acting as miRNA decoy. Lastly, the expression of HMGA1P7 was significantly correlated with H19 and IGF2 levels in human breast cancer thereby suggesting a role for HMGA1P7 deregulation in this neoplasia.

High Mobility Group A proteins in esophageal carcinomas

We have recently shown that HMGA2 is overexpressed in esophageal squamous cell carcinoma (ESCC) and its detection allows to discriminate between cancer and normal surrounding tissue proposing HMGA2 as a novel diagnostic marker. Interestingly, esophageal adenocarcinoma shows an opposite behavior with the overexpression of HMGA1 but not HMGA2. Moreover, we show that the suppression of HMGA2 in 2 ESCC cell lines reduces the malignant phenotype. Then, this paper highlights a differential induction of the HMGA proteins, depending on the cancer histological type, and reinforces the perspective of an innovative esophageal cancer therapy based on the suppression of the HMGA protein function and/or expression.

Expression of evolutionarily novel genes in tumors

The evolutionarily novel genes originated through different molecular mechanisms are expressed in tumors. Sometimes the expression of evolutionarily novel genes in tumors is highly specific. Moreover positive selection of many human tumor-related genes in primate lineage suggests their involvement in the origin of new functions beneficial to organisms. It is suggested to consider the expression of evolutionarily young or novel genes in tumors as a new biological phenomenon, a phenomenon of TSEEN (tumor specifically expressed, evolutionarily novel) genes.

HMGA1 facilitates tumor progression through regulating Wnt/β-catenin pathway in endometrial cancer

Recent studies have identified a unique role for high mobility group protein A1 (HMGA1) as a major regulator of tumor progression and in diverse tumor models. Emerging evidences indicate that overexpressed HMGA1 facilitates multiple malignant phenotypes of cancer cells, however, the oncogenic activities of HMGA1 in endometrial cancer (EC) remains elusive. Here we showed that HMGA1 was more frequently expressed in human EC tissues compared to non-tumor tissues. Elevated HMGA1 was significantly associated with advanced clinical stage. Wound-healing assay and transwell assay showed that HMGA1 can positively regulate cell migration and invasion. Mechanistically, luciferase reporter assay and Western blotting assay demonstrated that activation of Wnt/β-catenin pathway contributed to the oncogenic activity of HMGA1. Taken together, our data reveal that HMGA1 may function as an oncogene and modulate EC cell migration and invasion by activating Wnt/β-catenin pathway, implying that suppression of HMGA1 might be a potential therapeutic strategy for EC.

FTH1P3, a Novel H-Ferritin Pseudogene Transcriptionally Active, Is Ubiquitously Expressed and Regulated during Cell Differentiation

Ferritin, the major iron storage protein, performs its essential functions in the cytoplasm, nucleus and mitochondria. The variable assembly of 24 subunits of the Heavy (H) and Light (L) type composes the cytoplasmic molecule. In humans, two distinct genes code these subunits, both belonging to complex multigene families. Until now, one H gene has been identified with the coding sequence interrupted by three introns and more than 20 intronless copies widely dispersed on different chromosomes. Two of the intronless genes are actively transcribed in a tissue-specific manner. Herein, we report that FTH1P3, another intronless pseudogene, is transcribed. FTH1P3 transcript was detected in several cell lines and tissues, suggesting that its transcription is ubiquitary, as it happens for the parental ferritin H gene. Moreover, FTH1P3 expression is positively regulated during the cell differentiation process.

Pseudogenes in Human Cancer

Recent advances in the analysis of RNA sequencing data have shown that pseudogenes are highly specific markers of cell identity and can be used as diagnostic and prognostic markers. Furthermore, genetically engineered mouse models have recently provided compelling support for a causal link between altered pseudogene expression and cancer. In this review, we discuss the most recent milestones reached in the pseudogene field and the use of pseudogenes as cancer classifiers.

Epigenetic Mechanisms Leading to Overexpression of HMGA Proteins in Human Pituitary Adenomas

Overexpression of the high-mobility group A (HMGA)1 and HMGA2 proteins is a feature of all human pituitary adenoma (PAs) subtypes. However, amplification and/or rearrangement of the HMGA2 have been described in human prolactinomas, but rarely in other pituitary subtypes, and no genomic amplification of HMGA1 was detected in PAs. Here, we summarize the functional role of HMGA proteins in pituitary tumorigenesis and the epigenetic mechanisms contributing to HMGA overexpression in these tumors focusing on recent studies indicating a critical role of non-coding RNAs in modulating HMGA protein levels.