MicroRNA-206 inhibits the viability and migration of medulloblastoma cells by targeting LIM and SH3 protein 1

CircRNA and lncRNA-associated competing endogenous RNA networks in medulloblastoma: a scoping review

BACKGROUND

Medulloblastoma is one of the common primary central nervous system (CNS) malignancies in pediatric patients. The main treatment is surgical resection preceded and/or followed by chemoradiotherapy. However, their serious side effects necessitate a better understanding of medulloblastoma biology to develop novel therapeutic options.

MAIN BODY

Circular RNA (circRNA) and long non-coding RNA (lncRNA) regulate gene expression via microRNA (miRNA) pathways. Although growing evidence has highlighted the significance of circRNA and lncRNA-associated competing endogenous RNA (ceRNA) networks in cancers, no study has comprehensively investigated them in medulloblastoma. For this aim, the Web of Science, PubMed, Scopus, and Embase were systematically searched to obtain the relevant papers published before 16 September 2023, adhering to the PRISMA-ScR statement. HOTAIR, NEAT1, linc-NeD125, HHIP-AS1, CRNDE, and TP73-AS1 are the oncogenic lncRNAs, and Nkx2-2as is a tumor-suppressive lncRNA that develop lncRNA-associated ceRNA networks in medulloblastoma. CircSKA3 and circRNA_103128 are upregulated oncogenic circRNAs that develop circRNA-associated ceRNA networks in medulloblastoma.

CONCLUSION

In summary, this study has provided an overview of the existing evidence on circRNA and lncRNA-associated ceRNA networks and their impact on miRNA and mRNA expression involved in various signaling pathways of medulloblastoma. Suppressing the oncogenic ceRNA networks and augmenting tumor-suppressive ceRNA networks can provide ample opportunities for medulloblastoma treatment.

Role of MicroRNAs in the Development and Progression of the Four Medulloblastoma Subgroups

Medulloblastoma is the most frequent malignant brain tumour in children. Medulloblastoma originate during the embryonic stage. They are located in the cerebellum, which is the area of the central nervous system (CNS) responsible for controlling equilibrium and coordination of movements. In 2012, medulloblastoma were divided into four subgroups based on a genome-wide analysis of RNA expression. These subgroups are named Wingless, Sonic Hedgehog, Group 3 and Group 4. Each subgroup has a different cell of origin, prognosis, and response to therapies. Wingless and Sonic Hedgehog medulloblastoma are so named based on the main mutation originating these tumours. Group 3 and Group 4 have generic names because we do not know the key mutation driving these tumours. Gene expression at the post-transcriptional level is regulated by a group of small single-stranded non-coding RNAs. These microRNA (miRNAs or miRs) play a central role in several cellular functions such as cell differentiation and, therefore, any malfunction in this regulatory system leads to a variety of disorders such as cancer. The role of miRNAs in medulloblastoma is still a topic of intense clinical research; previous studies have mostly concentrated on the clinical entity of the single disease rather than in the four molecular subgroups. In this review, we summarize the latest discoveries on miRNAs in the four medulloblastoma subgroups.

Noncoding RNAs in pediatric brain tumors: Molecular functions and pathological implications

Brain tumors are common solid pediatric malignancies and the main reason for cancer-related death in the pediatric setting. Recently, evidence has revealed that noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), play a critical role in brain tumor development and progression. Therefore, in this review article, we describe the functions and molecular mechanisms of ncRNAs in multiple types of cancer, including medulloblastoma, pilocytic astrocytoma, ependymoma, atypical teratoid/rhabdoid tumor, glioblastoma, diffuse intrinsic pontine glioma, and craniopharyngioma. We also mention the limitations of using ncRNAs as therapeutic targets because of the nonspecificity of ncRNA targets and the delivery methods of ncRNAs. Due to the critical role of ncRNAs in brain oncogenesis, targeting aberrantly expressed ncRNAs might be an effective strategy to improve the outcomes of pediatric patients with brain tumors.

Molecular Determinants of Medulloblastoma Metastasis and Leptomeningeal Dissemination

Medulloblastoma is the most common malignant brain cancer in pediatrics consisting of four molecular subgroups, namely wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4. One of the biggest challenges in the clinical management of this disease is the leptomeningeal dissemination (LMD) of tumor cells with high morbidity and mortality. Many molecular regulators to date have been identified to participate in medulloblastoma metastasis. In the SHH subgroup, the co-upregulation of CXCR4 and PDGFR, as well as the activation of c-MET, show significant promigratory effects on medulloblastoma cells. Amplification or overexpression of genes on the long arm of chromosome 17, such as LASP1 and WIP1, facilitates tumor invasion in both Group 3 and Group 4 medulloblastomas. PRUNE1, NOTCH1, and MYC interactor JPO2 are more specific genetic drivers of metastatic Group 3 tumors. The RAS/MAPK and PI3K/AKT pathways are two crucial signal transduction pathways that may work as the convergent downstream mechanism of various metastatic drivers. Extracellular signals and cellular components in the tumor microenvironment also play a vital role in promoting the spread and colonization of medulloblastoma cells. For instance, the stromal granule cells and astrocytes support tumor growth and dissemination by secreting PlGF and CCL2, respectively. Importantly, the genetic divergence has been determined between the matched primary and metastatic medulloblastoma samples. However, the difficulty of obtaining metastatic medulloblastoma tissue hinders more profound studies of LMD. Therefore, identifying and analyzing the subclone with the metastatic propensity in the primary tumor is essential for future investigation.

The Non-coding Side of Medulloblastoma

Medulloblastoma (MB) is the most common pediatric brain tumor and a primary cause of cancer-related death in children. Until a few years ago, only clinical and histological features were exploited for MB pathological classification and outcome prognosis. In the past decade, the advancement of high-throughput molecular analyses that integrate genetic, epigenetic, and expression data, together with the availability of increasing wealth of patient samples, revealed the existence of four molecularly distinct MB subgroups. Their further classification into 12 subtypes not only reduced the well-characterized intertumoral heterogeneity, but also provided new opportunities for the design of targets for precision oncology. Moreover, the identification of tumorigenic and self-renewing subpopulations of cancer stem cells in MB has increased our knowledge of its biology. Despite these advancements, the origin of MB is still debated, and its molecular bases are poorly characterized. A major goal in the field is to identify the key genes that drive tumor growth and the mechanisms through which they are able to promote tumorigenesis. So far, only protein-coding genes acting as oncogenic drivers have been characterized in each MB subgroup. The contribution of the non-coding side of the genome, which produces a plethora of transcripts that control fundamental biological processes, as the cell choice between proliferation and differentiation, is still unappreciated. This review wants to fill this major gap by summarizing the recent findings on the impact of non-coding RNAs in MB initiation and progression. Furthermore, their potential role as specific MB biomarkers and novel therapeutic targets is also highlighted.

miR-196B-5P and miR-200B-3P Are Differentially Expressed in Medulloblastomas of Adults and Children

Medulloblastoma is a highly aggressive brain tumor that typically affects children, while in adults it represents ~1% of all brain tumors. Little is known about microRNA expression profile of the rare adult medulloblastoma. The main aim of this study was to identify peculiar differences in microRNA expression between childhood and adult medulloblastoma. Medulloblastomas were profiled for microRNA expression using the Exiqon Human miRNome panel (I + II) analyzing 752 microRNAs in a training set of six adult and six childhood cases. Then, the most differentially expressed microRNAs were validated in a total of 21 adult and 19 childhood cases. Eight microRNAs (miR-196b-5p, miR-183-5p, miR-200b-3p, miR-196a-5p, miR-193a-3p, miR-29c-3p, miR-33b-5p, and miR-200a-3p) were differentially expressed in medulloblastoma of adults and children. Analysis of the validation set confirmed that miR-196b-5p and miR-200b-3p were significantly overexpressed in medulloblastoma of adults as compared with those of children. We followed an in silico approach to investigate direct targets and the pathways involved for the two microRNAs (miR-196b and miR-200b) differently expressed between adult and childhood medulloblastoma. Adult and childhood medulloblastoma have different miRNA expression profiles. In particular, the differential dysregulation of miR-196b-5p and miR-200b-3p characterizes the miRNA profile of adult medulloblastoma and suggests potential targets for novel diagnostic, prognostic, or therapeutic strategies.

Long noncoding RNA HOTAIR promotes medulloblastoma growth, migration and invasion by sponging miR-1/miR-206 and targeting YY1

PURPOSE

Long non-coding RNA (LncRNA) HOX transcript antisense RNA (HOTAIR) and Yin Yang 1 (YY1) are reported to be involved in tumorigenesis. However, the effect and molecular mechanism of HOTAIR on YY1 expression remains poorly understood. The study aimed to investigate the functions and molecular mechanism of LncRNA HOTAIR in medulloblastoma progression.

METHODS

qPCR was performed to detect HOTAIR and YY1 mRNA in tissues and cells, as well as that of miR-1 and miR-206 expression levels. Western blot assay was used to test YY1 and EMT-related biomarkers' protein levels. Cell proliferation was tested with CCK-8 assay and colony formation assay. Migration and invasion abilities were tested with Transwell migration and invasion assays. Tumor growth was tested with an in vivo animal study. Cell apoptosis was tested with an Annexin V-FITC/PI kit. Luciferase assay was used to test the luciferase intensity of YY1 and HOTAIR. RNA pull down assay was used to detect the combination between HOTAIR and miR-1/miR-206.

RESULTS

In this study, we found that HOTAIR and YY1 were up-regulated in medulloblastoma tissues and cell lines, and HOTAIR increased YY1 expression. The molecular mechanism demonstrated that HOTAIR negatively regulated miR-1 and miR-206 expression, which can directly target YY1 in medulloblastoma cells. Moreover, HOTAIR increased YY1 expression through binding to miR-1 and miR-206. The functional experiments showed that HOTAIR knockdown suppressed medulloblastoma cell proliferation, tumor growth, migration and invasion, and promoted cell apoptosis via the modulation of the miR-1/miR-206-YY1 axis, as well as epithelial to mesenchymal transition (EMT).

CONCLUSION

These data indicate that HOTAIR promotes medulloblastoma progression via acting as a competing endogenous RNA (ceRNA) to regulate YY1 expression through binding to miR-1 and miR-206.

MicroRNA‑206 exerts anti‑oncogenic functions in esophageal squamous cell carcinoma by suppressing the c‑Met/AKT/mTOR pathway

Increasing evidence suggests that the dysregulation of microRNAs (miRNAs) has an important role in the progression of human cancer, including ESCC. However, the exact functions and mechanisms of miRNAs in ESCC remain largely unclear. The aim of the present study was to investigate the expression and biological functions of miRNAs in ESCC and reveal the underlying molecular mechanisms. miRNA microarray and reverse transcription-quantitative polymerase chain reaction analyses were performed, which identified and confirmed that miR-206 was significantly downregulated in ESCC tissues and cell lines. Its low expression was associated with lymph node metastasis, advanced TNM stage and N classification, as well as poorer overall survival in patients with ESCC. CCK-8 and flow cytometry assays demonstrated that ectopic miR-206 expression inhibited ESCC cell proliferation and induced cell apoptosis. In addition, MET proto-oncogene, receptor tyrosine kinase (c-Met), a well-known oncogene, was a direct target of miR-206. An inverse correlation between the levels of miR-206 and c-Met mRNA in ESCC tissue samples was confirmed. Notably, c-Met overexpression inhibited the effects of miR-206 on the proliferation and apoptosis of ESCC cells. Additionally, it was confirmed that the tumor-suppressive functions of miR-206 may have contributed to the inactivation of the c-Met/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) signaling pathway. In conclusion, the findings of the present study suggested that miR-206 exerts its anti-cancer functions via the c-Met/AKT/mTOR signaling pathway, providing a novel candidate prognostic factor and a potential therapeutic target in ESCC.

New Frontiers for the Cytoskeletal Protein LASP1

In the recent two decades, LIM and SH3 protein 1 (LASP1) has been developed from a simple actin-binding structural protein to a tumor biomarker and subsequently to a complex, nuclear transcriptional regulator. Starting with a brief historical perspective, this review will mainly compare and contrast LASP1 and LASP2 from the angle of the newest data and importantly, examine their role in transcriptional regulation. We will summarize the current knowledge through pictorial models and tables including the roles of different microRNAs in the differential regulation of LASP1 levels and patient outcome rather than specify in detail all tumor entities. Finally, the novel functional roles of LASP1 in secretion of vesicles, expression of matrix metalloproteinases and transcriptional regulation as well as the activation of survival and proliferation pathways in different cancer types are described.

MicroRNA-206 suppresses proliferation and predicts poor prognosis of HR-HPV-positive cervical cancer cells by targeting G6PD

Cervical cancer (CC) is one of the most frequent gynecological malignancies in females worldwide. Aberrant expression of microRNA (miR)-206 was reported to play an important role in tumor progression. The aim of the present study was to evaluate the potential role of miR-206 and verify its influence on the function of glucose-6-phosphate dehydrogenase (G6PD) in CC. Western blot analysis and RT-PCR were employed to measure miR-206 and G6PD expression. Luciferase assays were performed to validate G6PD as miR-206 targets. CCK-8 assay was performed to examine the regulation of miR-206 and G6PD on CC proliferation. The result showed that miR-206 was downregulated, while G6PD was upregulated in high risk human papillomavirus (HR-HPV)(+) CC. miR-206 directly targeted the 3'-UTR of G6PD. miR-206 overexpressed or G6PD low-expressed suppressed cell proliferation. miR-206 low expressed or G6PD overexpressed predicted poor prognosis. In conclusion, miR-206 reduced cancer growth and suppresses the G6PD expression in CC. This newly identified miR-206 may provide further insight into tumor progression and offers a promising target for the CC therapy.