miR-367 promotes uveal melanoma cell proliferation and migration by regulating PTEN

Genetic and Epigenetic Features of Uveal Melanoma-An Overview and Clinical Implications

Uveal melanoma (UM) is rare, but it is the most common primary intraocular malignancy among adults. This review represents the molecular, genetic, and immunobiological mechanisms involved in UM carcinogenesis and progression, as well as data about the association of chromosomal changes, genetic mutations, selective proteins, and biochemical biomarkers with the clinical implications of UM. Genetic analysis has the potential to identify patients with a high risk of UM metastasis, enabling management that is more effective and allowing for the follow-up of patients. Advancements in molecular characterization of UM offer opportunities to develop targeted therapeutic strategies by focusing on relevant signaling pathways. Changes in miRNA expression could be useful in the diagnosis and prognosis of UM, due to unique miRNA profiles in melanoma cells or tissue and its association with metastasis. Although liver function tests do not provide enough data on the prognosis of UM, due to the high frequency of liver metastasis, liver function tests (LFTs) might be useful indicators; however, the absence of rising LFT values cannot lead to the exclusion of liver metastases. Molecular analysis of tumor tissue will allow us to identify patients with the added benefit of new therapeutic agents and provide a better insight into melanoma pathogenesis and its biological behavior.

Genetics and RNA Regulation of Uveal Melanoma

Uveal melanoma (UM) is the most common intraocular malignant tumor and the most frequent melanoma not affecting the skin. While the rate of UM occurrence is relatively low, about 50% of patients develop metastasis, primarily to the liver, with lethal outcome despite medical treatment. Notwithstanding that UM etiopathogenesis is still under investigation, a set of known mutations and chromosomal aberrations are associated with its pathogenesis and have a relevant prognostic value. The most frequently mutated genes are BAP1, EIF1AX, GNA11, GNAQ, and SF3B1, with mutually exclusive mutations occurring in GNAQ and GNA11, and almost mutually exclusive ones in BAP1 and SF3B1, and BAP1 and EIF1AX. Among chromosomal aberrations, monosomy of chromosome 3 is the most frequent, followed by gain of chromosome 8q, and full or partial loss of chromosomes 1 and 6. In addition, epigenetic mechanisms regulated by non-coding RNAs (ncRNA), namely microRNAs and long non-coding RNAs, have also been investigated. Several papers investigating the role of ncRNAs in UM have reported that their dysregulated expression affects cancer-related processes in both in vitro and in vivo models. This review will summarize current findings about genetic mutations, chromosomal aberrations, and ncRNA dysregulation establishing UM biology.

PTEN as a target in melanoma

PTEN is a well-known tumour suppressor protein that is frequently found to be mutated, inactivated or deleted in a wide range of different cancers. Its tumour suppressive properties result predominantly from its inhibitory effects on the PI3K-AKT signalling pathway. In melanoma, numerous different PTEN mutations have been identified in both melanoma cell lines and melanoma tissue. A number of different molecules can act on PTEN to either promote its suppression of melanoma, while other molecules may antagonise PTEN to inhibit its mechanism of action against melanoma. This review will discuss how the interactions of PTEN with other molecules may have a positive or negative impact on melanoma pathogenesis, giving rise to the potential for PTEN-targeted therapies against melanoma.

Non-coding RNAs in melanoma: Biological functions and potential clinical applications

Malignant melanoma (MM) is a malignant tumor that originates from melanocytes and has a high mortality rate. Therefore, early diagnosis and treatment are very important for survival. So far, the exact molecular mechanism leading to the occurrence of melanoma, especially the molecular metastatic mechanism, remains largely unknown. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNA (circRNAs), have been investigated and found to play vital roles in regulating tumor occurrence and development, including melanoma. In this review, we summarize the progress of recent research on the effects of ncRNAs on melanoma and attempt to elucidate the role of ncRNAs as molecular markers or potential targets that will provide promising application perspectives on melanoma.

MiRNAs Correlate with HLA Expression in Uveal Melanoma: Both Up- and Downregulation Are Related to Monosomy 3

Simple Summary

Uveal melanoma (UM) is a rare ocular malignancy that often gives rise to metastases. Tumours with an inflammatory phenotype have an especially bad prognosis. As an increased HLA expression and the presence of tumour-infiltrating lymphocytes and macrophages may be regulated by miRNAs, we set out to investigate whether any miRNAs are associated with inflammatory parameters in this malignancy. Some miRNAs were increased in UM with a high HLA expression and high T cell numbers, while others were decreased, showing two opposing patterns; however, both patterns were related to the tumour’s chromosome 3/BAP1 status. We conclude that specific miRNAs are related to the inflammatory phenotype and that these are differentially expressed between disomy 3/BAP1-positive versus monosomy 3/BAP1-negative UM.

Abstract

MicroRNAs are known to play a role in the regulation of inflammation. As a high HLA Class I expression is associated with a bad prognosis in UM, we set out to determine whether any miRNAs were related to a high HLA Class I expression and inflammation. We also determined whether such miRNAs were related to the UM’s genetic status. The expression of 125 miRNAs was determined in 64 primary UM from Leiden. Similarly, the mRNA expression of HLA-A, HLA-B, TAP1, BAP1, and immune cell markers was obtained. Expression levels of 24 of the 125 miRNAs correlated with expression of at least three out of four HLA Class I probes. Four miRNAs showed a positive correlation with HLA expression and infiltration with leukocytes, 20 a negative pattern. In the first group, high miRNA levels correlated with chromosome 3 loss/reduced BAP1 mRNA expression, in the second group low miRNA levels. The positive associations between miRNA-22 and miRNA-155 with HLA Class I were confirmed in the TCGA study and Rotterdam cohort, and with TAP1 in the Rotterdam data set; the negative associations between miRNA-125b2 and miRNA-211 and HLA-A, TAP1, and CD4 were confirmed in the Rotterdam set. We demonstrate two patterns: miRNAs can either be related to a high or a low HLA Class I/TAP1 expression and the presence of infiltrating lymphocytes and macrophages. However, both patterns were associated with chromosome 3/BAP1 status, which suggests a role for BAP1 loss in the regulation of HLA expression and inflammation in UM through miRNAs.

The miR-302s/367 Cluster Inhibits the Proliferation and Apoptosis in Sheep Fetal Fibroblasts via the Cell Cycle and PI3K-Akt Pathways

The miR-302s/367 family has the ability to induce mouse and human somatic cell reprogramming into induced pluripotent stem cells (iPSCs), inhibit the proliferation of several types of cancer cells, and even cause cancer cell apoptosis. However, the functions of the miR-302s/367 family in other mammals have not been explored. In the present study, the effects of miR-302s/367 on reprogramming, proliferation, and apoptosis in sheep fetal fibroblasts (SFFs) were evaluated by the delivery of a plasmid vector containing synthetic precursor miRNAs into cells, followed by the induction of mature miR-302s/367 expression. The results showed that miR-302s/367 could not reprogram SFFs into iPSCs; however, they could inhibit both the proliferation and apoptosis of SFFs by targeting CDK2, E2F1, E2F2, and PTEN in the cell cycle and PI3K-Akt pathways. Based on our findings, a novel mechanism was proposed in which the miR-302s/367 family functions in both the proliferation and apoptosis of somatic cells in mammals, suggesting that caution is needed when using miR-302s/367 as therapeutic agent.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

Melanoma is the utmost fatal kind of skin neoplasms. Molecular changes occurring during the pathogenic processes of initiation and progression of melanoma are diverse and include activating mutations in BRAF and NRAS genes, hyper-activation of PI3K/AKT pathway, inactivation of p53 and alterations in CDK4/CDKN2A axis. Moreover, several miRNAs have been identified to be implicated in the biology of melanoma through modulation of expression of genes being involved in these pathways. In the current review, we provide a summary of the bulk of information about the role of miRNAs in the pathobiology of melanoma, their possible application as biomarkers and their emerging role as therapeutic targets for this kind of skin cancer.

MicroRNA-367 directly targets PIK3R3 to inhibit proliferation and invasion of oral carcinoma cells

Recently, microRNA-367 (miR-367) has been reported to function as both tumor suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer and lung cancer. However, the biological function of miR-367 and its precise mechanisms in oral squamous cell carcinoma (OSCC) have not been well clarified. The aim of the present study was to study the roles of miR-367/PIK3R3 axis in OSCC. The levels of PIK3R3 and miR-367 were detected by quantitative PCR assay in OSCC tissues and cell lines. Moreover, the biological roles of miR-367 and PIK3R3 in OSCC cells were assessed by cell proliferation and invasion. The mRNA and protein levels of PIK3R3 were determined by using quantitative PCR and Western blotting assays. Luciferase assays were used to confirm that PIK3R3 was one target of miR-367. In the present study, the miR-367 level was dramatically reduced in OSCC tissues and cell lines, and the PIK3R3 expression was significantly enhanced. What’s more, the PIK3R3 expression was negatively related to the miR-367 level in OSCC tissues. Furthermore, up-regulation of miR-367 obviously restrained OSCC cells proliferation and invasion. We confirmed that miR-367 could directly target PIK3R3 by luciferase reporter assay. Besides, knockdown of PIK3R3 also could markedly inhibit the proliferation and invasion of OSCC cells. Finally, overexpression of miR-367 in OSCC cells partially reversed the promoted effects of PIK3R3 up-regulation. Overexpression of miR-367 restrained OSCC cells proliferation and invasion via regulation of PIK3R3.

Current molecular and clinical insights into uveal melanoma (Review)

Uveal melanoma (UM) represents the most prominent primary eye cancer in adults. With an incidence of approximately 5 cases per million individuals annually in the United States, UM could be considered a relatively rare cancer. The 90-95% of UM cases arise from the choroid. Diagnosis is based mainly on a clinical examination and ancillary tests, with ocular ultrasonography being of greatest value. Differential diagnosis can prove challenging in the case of indeterminate choroidal lesions and, sometimes, monitoring for documented growth may be the proper approach. Fine needle aspiration biopsy tends to be performed with a prognostic purpose, often in combination with radiotherapy. Gene expression profiling has allowed for the grading of UMs into two classes, which feature different metastatic risks. Patients with UM require a specialized multidisciplinary management. Primary tumor treatment can be either enucleation or globe preserving. Usually, enucleation is reserved for larger tumors, while radiotherapy is preferred for small/medium melanomas. The prognosis is unfavorable due to the high mortality rate and high tendency to metastasize. Following the development of metastatic disease, the mortality rate increases to 80% within one year, due to both the absence of an effective treatment and the aggressiveness of the condition. Novel molecular studies have allowed for a better understanding of the genetic and epigenetic mechanisms involved in UM biological activity, which differs compared to skin melanomas. The most commonly mutated genes are GNAQ, GNA11 and BAP1. Research in this field could help to identify effective diagnostic and prognostic biomarkers, as well as novel therapeutic targets.

Emerging roles of microRNAs and their implications in uveal melanoma

Uveal melanoma (UM) is the most common intraocular malignant tumor in adults with an extremely high mortality rate. Genetic and epigenetic dysregulation contribute to the development of UM. Recent discoveries have revealed dysregulation of the expression levels of microRNAs (miRNAs) as one of the epigenetic mechanisms underlying UM tumorigenesis. Based on their roles, miRNAs are characterized as either oncogenic or tumor suppressive. This review focuses on the roles of miRNAs in UM tumorigenesis, diagnosis, and prognosis, as well as their therapeutic potentials. Particularly, the actions of collective miRNAs are summarized with respect to their involvement in major, aberrant signaling pathways that are implicated in the development and progression of UM. Elucidation of the underlying functional mechanisms and biological aspects of miRNA dysregulation in UM is invaluable in the development of miRNA-based therapeutics, which may be used in combination with conventional treatments to improve therapeutic outcomes. In addition, the expression levels of some miRNAs are correlated with UM initiation and progression and, therefore, may be used as biomarkers for diagnosis and prognosis.

Update on uveal melanoma: Translational research from biology to clinical practice (Review)

Uveal melanoma is the most common type of intraocular cancer with a low mean annual incidence of 5‑10 cases per million. Tumours are located in the choroid (90%), ciliary body (6%) or iris (4%) and of 85% are primary tumours. As in cutaneous melanoma, tumours arise in melanocytes; however, the characteristics of uveal melanoma differ, accounting for 3‑5% of melanocytic cancers. Among the numerous risk factors are age, sex, genetic and phenotypic predisposition, the work environment and dermatological conditions. Management is usually multidisciplinary, including several specialists such as ophthalmologists, oncologists and maxillofacial surgeons, who participate in the diagnosis, treatment and complex follow‑up of these patients, without excluding the management of the immense emotional burden. Clinically, uveal melanoma generates symptoms that depend as much on the affected ocular globe site as on the tumour size. The anatomopathological study of uveal melanoma has recently benefited from developments in molecular biology. In effect, disease classification or staging according to molecular profile is proving useful for the assessment of this type of tumour. Further, the improved knowledge of tumour biology is giving rise to a more targeted approach to diagnosis, prognosis and treatment development; for example, epigenetics driven by microRNAs as a target for disease control. In the present study, the main epidemiological, clinical, physiopathological and molecular features of this disease are reviewed, and the associations among all these factors are discussed.

The Role of Non-Coding RNAs in Uveal Melanoma

Simple Summary

The development of uveal melanoma is a multifactorial and multi-step process, in which abnormal gene expression plays a key role. Recently, several studies have highlighted the role of non-coding RNAs in the progression of uveal melanoma by affecting different signaling pathways. As important agents in the regulation of genes, non-coding RNAs have enormous potential to open up therapeutic pathways, predict response to treatment, and anticipate patient outcome for uveal melanoma. This review aims to provide a comprehensive view of what we know about ncRNAs in uveal melanoma currently.

Abstract

Uveal melanoma (UM) is the most common primary intraocular tumor in adulthood. Approximately 50% of patients develop metastatic disease, which typically affects the liver and is usually fatal within one year. This type of cancer is heterogeneous in nature and is divided into two broad groups of tumors according to their susceptibility to develop metastasis. In the last decade, chromosomal abnormalities and the aberrant expression of several signaling pathways and oncogenes in uveal melanomas have been described. Recently, importance has been given to the association of the mentioned deregulation with the expression of non-coding RNAs (ncRNAs). Here, we review the different classes of ncRNAs—such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs)—and their contribution to the development of UM. Special attention is given to miRNAs and their regulatory role in physiopathology and their potential as biomarkers. As important agents in gene regulation, ncRNAs have a huge potential for opening up therapeutic pathways, predicting response to treatment, and anticipating patient outcome for UM.

MicroRNAs and Uveal Melanoma: Understanding the Diverse Role of These Small Molecular Regulators

Uveal melanoma (UM) is a rare tumour of the eye, characterised by a high propensity to metastasise in half of all patients, most frequently to the liver. Although there are effective treatment options for the primary tumour, once metastasis has occurred prognosis is poor, with overall survival limited to months. Currently, there are no effective treatments for metastatic UM, despite the tumour having a well-defined signalling pathway to which many therapies have been directed. In an effort to develop novel treatment approaches, understanding the role of other signalling molecules, such as microRNAs, is fundamental. MicroRNAs (miRNAs) are small non-coding RNA molecules involved in posttranscriptional gene regulation, resulting in reduced target gene expression and subsequent protein translation. In UM, several dysregulated miRNAs have been proposed to play a functional role in disease progression, whereas others have been put forward as clinical biomarkers of high-risk disease following isolation from blood, plasma and exosomes. Most recently, analyses of large datasets have identified promising prognostic miRNA signatures and panels. This review navigates the plethora of aberrant miRNAs disclosed so far in UM, and maps these to signalling pathways, which could be targeted in future therapies for the disseminated disease.

A Review of MicroRNA in Uveal Melanoma

Uveal melanoma (UM) is the most common and aggressive primary intraocular tumor in adults. UM is classified as a malignant tumor with a strong tendency of metastasis, which always leads to poor outcomes. At present, the pathogenesis of UM remains unclear and lacks effective therapies. Recent studies have shown that microRNAs (miRNAs), defined as a group of 21-23 nucleotides single-stranded noncoding RNAs, play a significant role in UM. By binding to the complementary sites within the 3' untranslated region (3'UTR) of message RNAs (mRNAs), miRNAs regulate genes by decaying mRNAs or inhibiting their translation. Thus, miRNAs can modulate various biological behaviors of tumors, including cell proliferation, invasion and metastasis. Furthermore, miRNAs have shown clinical applications by serving as biomarkers for diagnosis and prognosis, regulating immune response, and functioning as epigenetic regulators. It is reasonable to believe that miRNAs have wide application prospects in the early diagnosis and therapy of UM.

Linc00961 inhibits the proliferation and invasion of skin melanoma by targeting the miR‑367/PTEN axis

Long intergenic noncoding RNA 00961 (Linc00961) has been identified as a tumor suppressor in various types of cancer. However, the critical roles of Linc00961 in the carcinogenesis and progression of skin melanoma (SM) are yet to be fully elucidated. The present study revealed via reverse transcription‑quantitative PCR analysis that Linc00961 was downregulated in the tissues of patients with SM compared with benign nevi, and in A375, A2058 and SK‑MEL‑28 cell lines compared with human melanocytes. Furthermore, overexpression of Linc00961 inhibited cell proliferation, and promoted the apoptosis of A375 and SK‑MEL‑28 cells in vitro and in vivo, as determined by Cell Counting Kit‑8 and flow cytometry assays, and tumor xenograft studies, respectively. Overexpression of Linc00961 also led to an attenuation of the migration and invasive capabilities of A375 and SK‑MEL‑28 cells, measured using Transwell assays. Functionally, it was demonstrated that Linc00961 acted as a competing endogenous RNA (ceRNA) by competitively sponging microRNA‑367 (miR‑367) in A375 and SK‑MEL‑28 cells; restoration of miR‑367 rescued the inhibitory effects of Linc00961 on A375 and SK‑MEL‑28 cells. Finally, it was observed that phosphate and tension homology deleted on chromosome 10 (PTEN), an established target of miR‑367 in A375 and SK‑MEL‑28 cells, was positively regulated by Linc00961, and its inhibition reversed the inhibitory effects of Linc00961 on the proliferation and invasion of A375 and SK‑MEL‑28 cells. Collectively, the present study revealed that Linc00961 was downregulated in SM, and furthermore, Linc00961 was identified as a ceRNA that inhibits the proliferation and invasion of A375 and SK‑MEL‑28 cells by modulating the miR‑367/PTEN axis.

Emerging Therapeutic Opportunities Based on Current Knowledge of Uveal Melanoma Biology

Uveal Melanoma (UM) is a rare and malignant intraocular tumor with dismal prognosis. Despite the efficient control of the primary tumor by radiation or surgery, up to 50% of patients subsequently develop metastasis, mainly in the liver. Once the tumor has spread from the eye, the treatment is challenging and the median survival is only nine months. UM represents an intriguing model of oncogenesis that is characterized by a relatively homogeneous histopathological architecture and a low burden of genetic alterations, in contrast to other melanomas. UM is driven by recurrent activating mutations in Gαq pathway, which are associated with a second mutation in BRCA1 associated protein 1 (BAP1), splicing factor 3b subunit 1 (SF3B1), or eukaryotic translation initiation factor 1A X-linked (EIF1AX), occurring in an almost mutually exclusive manner. The monosomy of chromosome 3 is also a recurrent feature that is associated with high metastatic risk. These events driving UM oncogenesis have been thoroughly investigated over the last decade. However, no efficient related therapeutic strategies are yet available and the metastatic disease remains mostly incurable. Here, we review current knowledge regarding the molecular biology and the genetics of uveal melanoma and highlight the related therapeutic applications and perspectives.

Circular RNA YAP1 inhibits the proliferation and invasion of gastric cancer cells by regulating the miR-367-5p/p27 Kip1 axis

Background

Circular RNAs (circRNAs) are a new type of non-coding RNAs and their functions in gastric cancer (GC) remain unclear. Recent studies have revealed that circRNAs play an important role in cancer development and certain types of pathological responses, acting as microRNA (miRNA) sponges to regulate gene expression.

Methods

CircNet was used to screen potential circRNAs and validated circYAP1 expression levels in 17 GC tissues by quantitative real-time PCR (qRT-PCR) and another 80 paired GC tissues by FISH. CircYAP1 overexpression and knockdown experiments were conducted to assess the effects of circYAP1 in vitro and in vivo, and its molecular mechanism was demonstrated by RNA in vivo precipitation assays, western blotting, luciferase assay and rescue experiments.

Results

CircYAP1 expression level was significantly lower in GC tissues than the adjacent normal tissues, and GC patients with circYAP1 low expression had shorter survival times as compared with those with circYAP1 high expression. Functionally, circYAP1 overexpression inhibited cell growth and invasion in vitro and in vivo, but its knockdown reversed these effects. Further analysis showed that circYAP1 sponged miR-367-5p to inhibit p27 ^Kip1 expression and GC progression.

Conclusion

Our findings demonstrate that circYAP1 functions as a tumor suppressor in GC cells by targeting the miR-367-5p/p27 ^Kip1 axis and may provide a prognostic indicator of survival in GC patients.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0902-1) contains supplementary material, which is available to authorized users.