Global microRNA profiling of metastatic conjunctival melanoma

The role of microRNAs in brain metastasis

Brain metastasis (BM) is the most common type of brain tumor and frequently foreshadows disease progression and poor overall survival with patients having a median survival of 6 months. 70,000 new cases of BM are diagnosed each year in the United States (US) and the incidence rate for BM is increasing with improved detection. MicroRNAs (miRNAs) are small non-coding RNAs that serve as critical regulators of gene expression and can act as powerful oncogenes and tumor suppressors. MiRNAs have been heavily implicated in cancer and proposed as biomarkers or therapeutic targets or agents. In this review, we summarize an extensive body of scientific work investigating the role of microRNAs in BM. We discuss miRNA dysregulation, functions, targets, and mechanisms of action in BM and present the current standing of miRNAs as biomarkers and potential therapeutics for BM. We conclude with future directions of miRNA basic and clinical research in BM.

The Significance of MicroRNAs in the Molecular Pathology of Brain Metastases

Brain metastases are the most frequent intracranial tumors in adults and the cause of death in almost one-fourth of cases. The incidence of brain metastases is steadily increasing. The main reason for this increase could be the introduction of new and more efficient therapeutic strategies that lead to longer survival but, at the same time, cause a higher risk of brain parenchyma infiltration. In addition, the advances in imaging methodology, which provide earlier identification of brain metastases, may also be a reason for the higher recorded number of patients with these tumors. Metastasis is a complex biological process that is still largely unexplored, influenced by many factors and involving many molecules. A deeper understanding of the process will allow the discovery of more effective diagnostic and therapeutic approaches that could improve the quality and length of patient survival. Recent studies have shown that microRNAs (miRNAs) are essential molecules that are involved in specific steps of the metastatic cascade. MiRNAs are endogenously expressed small non-coding RNAs that act as post-transcriptional regulators of gene expression and thus regulate most cellular processes. The dysregulation of these molecules has been implicated in many cancers, including brain metastases. Therefore, miRNAs represent promising diagnostic molecules and therapeutic targets in brain metastases. This review summarizes the current knowledge on the importance of miRNAs in brain metastasis, focusing on their involvement in the metastatic cascade and their potential clinical implications.

An Insight into miR-1290: An Oncogenic miRNA with Diagnostic Potential

For more than two decades, the view of the roles of non-coding RNAs (ncRNAs) has been radically changing. These RNA molecules that are transcribed from our genome do not have the capacity to encode proteins, but are critical regulators of gene expression at different levels. Our knowledge is constantly enriched by new reports revealing the role of these new molecular players in the development of many pathological conditions, including cancer. One of the ncRNA classes includes short RNA molecules called microRNAs (miRNAs), which are involved in the post-transcriptional control of gene expression affecting various cellular processes. The aberrant expression of miRNAs with oncogenic and tumor-suppressive function is associated with cancer initiation, promotion, malignant transformation, progression and metastasis. Oncogenic miRNAs, also known as oncomirs, mediate the downregulation of tumor-suppressor genes and their expression is upregulated in cancer. Nowadays, miRNAs show promising application in diagnosis, prediction, disease monitoring and therapy response. Our review presents a current view of the oncogenic role of miR-1290 with emphasis on its properties as a cancer biomarker in clinical medicine.

The potential role of miR-1290 in cancer progression, diagnosis, prognosis, and treatment: An oncomiR or onco-suppressor microRNA?

Cancer is one of the leading causes of death in humans because of the lack of early diagnosis, distant metastases, and the resistance to adjuvant therapies, including chemotherapy and radiotherapy. In addition to playing an essential role in tumor progression and development, microRNAs (miRNAs) can be used as a robust biomarker in the early detection of cancer. MiR-1290 was discovered for the first time in human embryonic stem cells, and under typical physiological situations, plays an essential role in neuronal differentiation and neural stem cell proliferation. Its coding sequence is located at the 1p36.13 regions in the first intron of the aldehyde dehydrogenase 4 gene member A1. miR-1290 is out of control in many cancers such as breast cancer, colorectal cancer, esophageal squamous cell carcinoma, gastric cancer, lung cancer, pancreatic cancer, and plays a vital role in their development. Therefore, it is suggested that miR-1290 can be considered as a potential diagnostic and therapeutic target in many cancers. In addition to the importance of miR-1290 in the noninvasive diagnosis of various cancers, this systematic review study discussed the role of miR-1290 in altering the expression of different genes involved in cancer development and chemo-radiation resistance. Moreover, it considered the regulatory effect of natural products on miR-1290 expression and the interaction of lncRNAs by miR-1290.

Differential and Common Signatures of miRNA Expression and Methylation in Childhood Central Nervous System Malignancies: An Experimental and Computational Approach

Epigenetic modifications are considered of utmost significance for tumor ontogenesis and progression. Especially, it has been found that miRNA expression, as well as DNA methylation plays a significant role in central nervous system tumors during childhood. A total of 49 resected brain tumors from children were used for further analysis. DNA methylation was identified with methylation-specific MLPA and, in particular, for the tumor suppressor genes CASP8, RASSF1, MGMT, MSH6, GATA5, ATM1, TP53, and CADM1. miRNAs were identified with microarray screening, as well as selected samples, were tested for their mRNA expression levels. CASP8, RASSF1 were the most frequently methylated genes in all tumor samples. Simultaneous methylation of genes manifested significant results with respect to tumor staging, tumor type, and the differentiation of tumor and control samples. There was no significant dependence observed with the methylation of one gene promoter, rather with the simultaneous presence of all detected methylated genes' promoters. miRNA expression was found to be correlated to gene methylation. Epigenetic regulation appears to be of major importance in tumor progression and pathophysiology, making it an imperative field of study.

Current Management of Conjunctival Melanoma Part 2: Treatment and Future Directions

Conjunctival melanoma is a rare disease which requires tailored management in most cases. The mainstays of treatment can be classified as surgery, topical chemotherapy, radiotherapy, cryotherapy, and other emerging treatment modalities. Herein we review conventional approaches as well as more recently introduced treatment options, together with advances in molecular biology in this particular disease.

Altered Expression of miR-575 in Glioma is Related to Tumor Cell Proliferation, Migration, and Invasion

Glioma is a kind of brain tumor with low overall survival and treatment success rates in the advanced stage. Evidence has shown microRNA-575 (miR-575) plays an important role in the generation and development of various cancers. This study aimed to explore the function of miR-575 in the prognosis and cell biological behavior of glioma. qRT-PCR was used to evaluate the expression of miR-575 in glioma tissues and cells, Kaplan-Meier survival analysis and Cox regression analysis were used to evaluate the prognostic value. The proliferation ability of glioma cells was determined by MTT assay; the invasion and migration abilities were determined by transwell assays. Compared with normal brain tissues, the expression of miR-575 in glioma tissue cells was significantly up-regulated (P < 0.001). The survival rate of patients in the miR-575 high expression group was significantly lower than that in the low expression group (P = 0.020). In addition, the overexpression of miR-575 promoted the proliferation, migration, and invasion of glioma cells. The results of this study suggested that miR-575 may be a new biomarker for the prognosis of glioma.

Conjunctival melanoma: New insights in tumour genetics and immunology, leading to new therapeutic options

Recent developments in oncology have led to a better molecular and cellular understanding of cancer, and the introduction of novel therapies. Conjunctival melanoma (CoM) is a rare but potentially devastating disease. A better understanding of CoM, leading to the development of novel therapies, is urgently needed. CoM is characterized by mutations that have also been identified in cutaneous melanoma, e.g. in BRAF, NRAS and TERT. These mutations are distinct from the mutations found in uveal melanoma (UM), affecting genes such as GNAQ, GNA11, and BAP1. Targeted therapies that are successful in cutaneous melanoma may therefore be useful in CoM. A recent breakthrough in the treatment of patients with metastatic cutaneous melanoma was the development of immunotherapy. While immunotherapy is currently sparsely effective in intraocular tumours such as UM, the similarities between CoM and cutaneous melanoma (including in their immunological tumour micro environment) provide hope for the application of immunotherapy in CoM, and preliminary clinical data are indeed emerging to support this use. This review aims to provide a comprehensive overview of the current knowledge regarding CoM, with a focus on the genetic and immunologic understanding. We elaborate on the distinct position of CoM in contrast to other types of melanoma, and explain how new insights in the pathophysiology of this disease guide the development of new, personalized, treatments.

Identification of Novel Biomarkers Associated With the Prognosis and Potential Pathogenesis of Breast Cancer via Integrated Bioinformatics Analysis

Background:

Breast cancer is the most commonly diagnosed malignancy and a major cause of cancer-related deaths in women globally. Identification of novel prognostic and pathogenesis biomarkers play a pivotal role in the management of the disease.

Methods:

Three data sets from the GEO database were used to identify differentially expressed genes (DEGs) in breast cancer. Gene Ontology (GO) enrichment and Kyoto Encyclopaedia of Genes and Genomes pathway analyses were performed to elucidate the functional roles of the DEGs. Besides, we investigated the translational and protein expression levels and survival data of the DEGs in patients with breast cancer from the Gene Expression Profiling Interactive Analysis (GEPIA), Oncomine, Human Protein Atlas, and Kaplan Meier plotter tool databases. The corresponding change in the expression level of microRNAs in the DEGs was also predicted using miRWalk and TargetScan, and the expression profiles were analyzed using OncomiR. Finally, the expression of novel DEGs were validated in Chinese breast cancer tissues by RT-qPCR.

Results:

A total of 46 DEGs were identified, and GO analysis revealed that these genes were mainly associated with biological processes involved in fatty acid, lipid localization, and regulation of lipid metabolism. Two novel biomarkers, ADH1A and IGSF10, and 4 other genes (APOD, KIT, RBP4, and SFRP1) that were implicated in the prognosis and pathogenesis of breast cancer, exhibited low expression levels in breast cancer tissues. Besides, 14/25 microRNAs targeting 6 genes were first predicted to be associated with breast cancer prognosis. RT-qPCR results of ADH1A and IGSF10 expression in Chinese breast cancer tissues were consistent with the database analysis and showed significant down-regulation.

Conclusion:

ADH1A, IGSF10, and the 14 microRNAs were found to be potential novel biomarkers for the diagnosis, treatment, and prognosis of breast cancer.

Genetic drivers of non-cutaneous melanomas: Challenges and opportunities in a heterogeneous landscape

Non-cutaneous melanomas most frequently involve the uveal tract and mucosal membranes, including the conjunctiva. In contrast to cutaneous melanoma, they often present at an advanced clinical stage, are associated with worse clinical outcomes and show poorer responses to immunotherapy. The mutational load within most non-cutaneous melanomas reflects their lower ultraviolet light (UV) exposure. The genetic drivers within non-cutaneous melanomas are heterogeneous. Within ocular melanomas, posterior uveal tract melanomas typically harbour one of two distinct, sets of driver mutations and alterations of clinical and biological significance. In contrast to posterior uveal tract melanomas, anterior uveal tract melanomas of the iris and conjunctival melanomas frequently carry both a higher mutational burden and specific mutations linked with UV exposure. The genetic drivers in iris melanomas more closely resemble those of the posterior uveal tract, whereas conjunctival melanomas harbour similar genetic driver mutations to cutaneous melanomas. Mucosal melanomas occur in sun-shielded sites including sinonasal and oral cavities, nasopharynx, oesophagus, genitalia, anus and rectum, and their mutational landscape is frequently associated with a dominant process of spontaneous deamination and infrequent presence of UV mutation signatures. Genetic drivers of mucosal melanomas are diverse and vary with anatomic location. Further understanding of the causes of already identified recurrent molecular events in non-cutaneous melanomas, identification of additional drivers in specific subtypes, integrative multi-omics analyses and analysis of the tumor immune microenvironment will expand knowledge in this field. Furthermore, such data will likely uncover new therapeutic strategies which will lead to improved clinical outcomes in non-cutaneous melanoma patients.

lncRNA LIFR‑AS1 inhibits gastric carcinoma cell proliferation, migration and invasion by sponging miR‑4698

The vital functions of long non-coding (lnc)RNAs have been verified in gastric carcinoma (GC). However, as a novel cancer-related lncRNA, the influence of leukemia inhibitory factor receptor antisense RNA 1 (LIFR-AS1) in GC cell biological behaviors remains unreported. The present study explored the biological effects of lncRNA LIFR-AS1 on GC progression. Reverse transcription-quantitative PCR was performed to examine lncRNA LIFR-AS1 expression in GC tissues and cells. Cell Counting Kit-8, 5-ethynyl-2′-deoxyuridine incorporation, cell wound healing and Transwell invasion assays were used to assess the functions of lncRNA LIFR-AS1 in GC cell proliferation, migration and invasion. Additionally, associations among lncRNA LIFR-AS1, microRNA (miR)-4698 and microtubule-associated tumor suppressor 1 (MTUS1) were investigated via bioinformatics software and a luciferase reporter system. In addition, western blotting was used to examine the expression of MEK and ERK. Decreased lncRNA LIFR-AS1 expression was observed in GC tissues and cells. Upregulated lncRNA LIFR-AS1 inhibited GC cell proliferation, migration and invasion. Upregulated miR-4698 and downregulated MTUS1 were identified in GC tissues and cells. The inhibitory interaction between lncRNA LIFR-AS1 and miR-4698 was confirmed. Additionally, MTUS1 was predicted as a target gene of miR-4698 positively regulated by lncRNA LIFR-AS1. The MEK/ERK pathway was inhibited by lncRNA LIFR-AS1 via regulating MTUS1. These findings revealed the inhibitory functions of lncRNA LIFR-AS1 in GC cell proliferation, migration and invasion. The process was mediated via miR-4698, MTUS1 and the MEK/ERK pathway.

Lnc-MCEI mediated the chemosensitivity of esophageal squamous cell carcinoma via miR-6759-5p to competitively regulate IGF2

Large amounts of long non-coding RNAs (lncRNAs) have been annotated whereas most of them have not been functionally characterized. Here we identified lncRNA ENST00000441932 as an oncogenic lncRNA in esophageal squamous cell carcinoma (ESCC) and named lnc-MCEI (lncRNA mediated the chemosensitivity of ESCC by regulating IGF2). What's more, the effect of lnc-MCEI on the chemosensitivity of ESCC was further evaluated. Bioinformatics analysis demonstrated that lnc-MCEI was involved in the tumorigenesis of ESCC and lnc-MCEI levels were significantly increased in ESCC cells and tissues. Additionally, lnc-MCEI knockdown retarded cell proliferation, colony formation of ESCC cells, but induced cell apoptosis. Moreover, lnc-MCEI knockdown significantly improved the chemosensitivity of ESCC to cisplatin (DDP) both in vivo and in vitro. Further mechanisms disclosed that lnc-MCEI functioned as a competing endogenous RNA (ceRNA) via sponging miR-6759-5p and IGF2 was a target of miR-6759-5p. Meanwhile, we found that IGF2 suppressed chemosensitivity of ESCC cells via PI3K/AKT pathway. These data suggested that lnc-MCEI was an oncogenic lncRNA and lnc-MCEI knockdown enhanced chemosensitivity of ESCC cells to cisplatin by targeting miR-6759-5p /IGF2/PI3K/AKT axis.

Conjunctival Melanoma: Current Treatments and Future Options

Conjunctival melanoma is a rare tumor of the conjunctival epithelium with a heterogenous clinical presentation and a propensity for regional and distant metastatic spread. Guidelines for the treatment of local conjunctival melanoma are well-established, but there are no standard efficacious therapies for metastatic disease. Given that conjunctival melanoma is genetically similar to cutaneous melanoma and mucosal melanomas, targeted therapies effective in the treatment of these diseases, such as BRAF inhibitors and KIT inhibitors, may be effective in the treatment of patients with metastatic conjunctival melanoma. Other targeted small-molecule drugs in the drug development pipeline for the treatment of more prevalent melanomas could also be applicable to conjunctival melanoma. Furthermore, systemic immunotherapy treatments that are now a mainstay in the treatment of cutaneous melanoma, such as programmed cell death-1 and cytotoxic T lymphocyte-associated antigen-4 inhibitors, could also stand to benefit patients with metastatic conjunctival melanoma. Limited case reports provide clues about the effectiveness of both targeted small-molecule inhibitors and immunotherapy in patients with advanced local and metastatic conjunctival melanoma and give credence to the argument that conjunctival melanoma patients should be included in major trials studying new therapies in both cutaneous and mucosal melanomas where applicable.

Hypoxia-Induced Adaptations of miRNomes and Proteomes in Melanoma Cells and Their Secreted Extracellular Vesicles

Reduced levels of intratumoural oxygen are associated with hypoxia-induced pro-oncogenic events such as invasion, metabolic reprogramming, epithelial–mesenchymal transition, metastasis and resistance to therapy, all favouring cancer progression. Small extracellular vesicles (EV) shuttle various cargos (proteins, miRNAs, DNA and others). Tumour-derived EVs can be taken up by neighbouring or distant cells in the tumour microenvironment, thus facilitating intercellular communication. The quantity of extracellular vesicle secretion and their composition can vary with changing microenvironmental conditions and disease states. Here, we investigated in melanoma cells the influence of hypoxia on the content and number of secreted EVs. Whole miRNome and proteome profiling revealed distinct expression patterns in normoxic or hypoxic growth conditions. Apart from the well-known miR-210, we identified miR-1290 as a novel hypoxia-associated microRNA, which was highly abundant in hypoxic EVs. On the other hand, miR-23a-5p and -23b-5p were consistently downregulated in hypoxic conditions, while the protein levels of the miR-23a/b-5p-predicted target IPO11 were concomitantly upregulated. Furthermore, hypoxic melanoma EVs exhibit a signature consisting of six proteins (AKR7A2, DDX39B, EIF3C, FARSA, PRMT5, VARS), which were significantly associated with a poor prognosis for melanoma patients, indicating that proteins and/or miRNAs secreted by cancer cells may be exploited as biomarkers.

miR-548x and miR-4698 controlled cell proliferation by affecting the PI3K/AKT signaling pathway in Glioblastoma cell lines

Glioblastoma multiforme (GBM) is the most aggressive and prevalent form of brain tumor cancers that originate from glial cells. This study proposed to investigate the effect of miR-548x and miR-4698 on the proliferation and the PI3K/AKT signaling pathway in glioblastoma cell lines. The molecular features of glioblastoma were studied using KEGG and TCGA sites. Next, by using miRwalk 2.0 and TargetScan version 7.1, the microRNAs that target critical genes in the PI3k/AKT pathway were selected according to score. The pre-miR-548x and pre-miR-4698 were cloned in a pCDH plasmid to produced lentiviral vector. The expression levels of miR-548x, miR-4698 and target genes were detected by qRT-PCR. The MTT, cell cycle, annexin and colony formation assay was used to detect the cell proliferation. MiR-548x and miR-4698 predicted target genes (Rheb, AKT1, mTOR, PDK1) were also evaluated by luciferase assay. The expression of AKT was detected by western blotting. Our results described that overexpression of miR-548x and miR-4698 could inhibit proliferation of A-172 and U251 cells. Also, miR-548x promoted the cell cycle arrest of GBM cell lines. The luciferase reporter assay results showed the 3′ UTR of PDK1, RHEB, and mTOR are direct targets of the miR-548x and miR-4698. Too, the western blot analysis revealed that miR-548x and miR-4698 could downregulate the AKT1 protein expression. Overall, our findings suggest that miR-548x and miR-4698 could function as tumor suppressor genes in glioblastoma by controlling the PI3K/AKT signaling pathway and may act as gene therapy for clinical treatment of glioblastoma multiforme.