miR-524-5p suppresses the growth of oncogenic BRAF melanoma by targeting BRAF and ERK2

Circulating MicroRNAs: functional biomarkers for melanoma prognosis and treatment

MicroRNAs (miRNAs) hold significant promise as circulating cancer biomarkers and unlike many other molecular markers, they can provide valuable insights that extend beyond tumour biology. The expression of circulating miRNAs may parallel the cellular composition and dynamic activity within the tumour microenvironment and reveal systemic immune responses. The functional complexity of miRNAs-where a single miRNA can regulate multiple messenger RNAs (mRNAs) to fine tune fundamental processes, and a single mRNA can be targeted by multiple miRNAs-underscores their broad significance and impact. However, this complexity poses significant challenges for translating miRNA research into clinical practice. In melanoma, specific miRNA signatures have shown notable diagnostic, prognostic and predictive value, with lineage-specific and immune-related miRNAs frequently identified as valuable markers. In this review, we explore the role of circulating miRNAs as potential biomarkers in melanoma, and highlight the current status and advances required to translate miRNA research into therapeutic opportunities.

The Role of Non-coding RNAs in Tumorigenesis, Diagnosis/Prognosis, and Therapeutic Strategies for Cutaneous Melanoma

RNA is a substance with various biological functions. It serves as blueprint for proteins and shuttles information from the genes to the protein factories of the cells. However, these factories-the ribosomes-are also composed mainly of RNA, whose purpose is not storing information but enzymatic action. In addition, there is a cornucopia of RNA molecules within our cells that form a complex regulatory network, connected with all aspects of cellular development and maintenance. These non-coding RNAs can be used for diagnostics and therapeutic strategies in cancer. In this chapter we give an overview of recent developments in non-coding RNA-based diagnostics and therapies for cutaneous melanoma. It is not meant to be comprehensive; however, it describes examples based on some of the most recent publications in this field.

Non-coding RNAs in BRAF-mutant melanoma: targets, indicators, and therapeutic potential

Melanoma, a highly aggressive skin cancer, is often driven by BRAF mutations, such as the V600E mutation, which promotes cancer growth through the MAPK pathway and contributes to treatment resistance. Understanding the role of non-coding RNAs (ncRNAs) in these processes is crucial for developing new therapeutic strategies. This review aims to elucidate the relationship between ncRNAs and BRAF mutations in melanoma, focusing on their regulatory roles and impact on treatment resistance. We comprehensively reviewed current literature to synthesize evidence on ncRNA-mediated regulation of BRAF-mutant melanoma and their influence on therapeutic responses. Key ncRNAs, including microRNAs and long ncRNAs, were identified as significant regulators of melanoma development and therapy resistance. MicroRNAs such as miR-15/16 and miR-200 families modulate critical pathways like Wnt signaling and melanogenesis. Long ncRNAs like ANRIL and SAMMSON play roles in cell growth, invasion, and drug susceptibility. Specific ncRNAs, such as BANCR and RMEL3, intersect with the MAPK pathway, highlighting their potential as therapeutic targets or biomarkers in BRAF-mutant melanoma. Additionally, ncRNAs involved in drug resistance, such as miR-579-3p and miR-1246, target processes like autophagy and immune checkpoint regulation. This review highlights the pivotal roles of ncRNAs in regulating BRAF-mutant melanoma and their contribution to drug resistance. These findings underscore the potential of ncRNAs as biomarkers and therapeutic targets, paving the way for innovative treatments to improve outcomes for melanoma patients.

Reconnoitring signaling pathways and exploiting innovative approaches tailoring multifaceted therapies for skin cancer

Nowadays, skin cancer is widespread just like a varied malignant cancer which can cause serious health issues. Skin cancer, which encompasses malignant melanoma, basal cell carcinoma, and squamous cell carcinoma, is a prevalent form of cancer among humans. Due to its broad prevalence, financial burden, mortality rates, and cosmetic effects, it is a major public health issue. Skin cancer treatment involves surgery, chemotherapy, and radiation. Recently, personalized treatment in the fields of targeted therapies and precision medicine has been shown to diagnose early detection of every individual tumor by knowing their genetic and molecular characteristics. To target the molecular pathways responsible for tumor growth and reduce the damage to healthy tissue, new targeted therapies have emerged for melanoma, basal cell carcinoma, and squamous cell carcinoma. B-raf serine/threonine kinase (BRAF) and mitogen-activated protein kinase (MEK) inhibitors, immune checkpoint inhibitors, and precision medications have strong response rates to improve patient survival. Targeted therapeutics like nanocarriers have shown promising results by reducing skin irritation and protecting encapsulated therapeutics. These formulations have been shown to improve the transdermal permeability of anticancer drugs. The consideration of employing physical techniques to enhance the permeation of nanocarriers warrants attention to augment the dermal permeation of anticancer agents and facilitate targeted drug delivery within neoplastic cells. Targeted therapies face obstacles like resistance mechanisms and treatment strategy monitoring. Taken together, this review delves into the basic mechanisms of skin cancer, current treatment methods, drug resistance processes, and nano-based targeted techniques for cancer treatment. It will also delineate the challenges and perspectives in pre-clinical and clinical contexts.

miR-876-3p is a tumor suppressor on 9p21 that is inactivated in melanoma and targets ERK

BACKGROUND

While melanomas commonly harbor losses of 9p21, on which CDKN2A resides, the presence of additional tumor suppressor elements at this locus is incompletely characterized. Here we assess the expression levels and functional role of microRNA-876-3p (miR-876), whose gene also maps to 9p21.

METHODS

Expression of miR-876 was assessed in human tissues and cell lines using quantitative miRNA reverse transcriptase polymerase chain reaction (qRT-PCR). MIR876 copy number was determined in The Cancer Genome Atlas (TCGA) melanoma cohort. The consequences of regulation of miR-876 expression were assessed on melanoma cell colony formation, migration, invasion, apoptosis, cell cycle progression, and drug sensitivity in culture, and on in vivo tumor growth in a xenograft model. Genome-wide transcriptomic changes induced by miR-876 overexpression were determined using RNA sequencing (RNA-Seq).

RESULTS

miR-876 expression was significantly decreased in primary melanoma samples when compared with nevi, and in human melanoma cell lines when compared with human melanocytes. Analysis of the TCGA cohort revealed deletions in MIR876 in > 50% of melanomas. miR-876 overexpression resulted in decreased melanoma cell colony formation, migration, and invasion, which was accompanied by cell cycle arrest and increased apoptosis. Intra-tumoral injections of miR-876 significantly suppressed melanoma growth in vivo. RNA-Seq analysis of miR-876-treated tumors revealed downregulation of several growth-promoting genes, along with upregulation of tumor suppressor genes, which was confirmed by qRT-PCR analysis. Computational analyses identified MAPK1 (or ERK2) as a possible target of miR-876 action. Overexpression of miR-876 significantly suppressed luciferase expression driven by the MAPK1/ERK2 3' UTR, and resulted in decreased ERK protein expression in melanoma cells. MAPK1/ERK2 cDNA overexpression rescued the effects of miR-876 on melanoma colony formation. miR-876 overexpression sensitized melanoma cells to treatment with the BRAF inhibitor vemurafenib.

CONCLUSIONS

These studies identify miR-876 as a distinct tumor suppressor on 9p21 that is inactivated in melanoma and suggest miR-876 loss as an additional mechanism to activate ERK and the mitogen activated protein kinase (MAPK) pathway in melanoma. In addition, they suggest the therapeutic potential of combining miR-876 overexpression with BRAF inhibition as a rational therapeutic strategy for melanoma.

miRNAs and related genetic biomarkers according to the WHO glioma classification: From diagnosis to future therapeutic targets

In the 2021 WHO classification of Tumors of the Central Nervous System, additional molecular characteristics have been included, defining the following adult-type diffuse glioma entities: Astrocytoma IDH-mutant, Oligodendroglioma IDH-mutant and 1p/19q-codeleted, and Glioblastoma IDH-wildtype. Despite advances in genetic analysis, precision oncology, and targeted therapy, malignant adult-type diffuse gliomas remain "hard-to-treat tumors", indicating an urgent need for better diagnostic and therapeutic strategies. In the last decades, miRNA analysis has been a hotspot for researching and developing diagnostic, prognostic, and predictive biomarkers for various disorders, including brain cancer. Scientific interest has recently been directed towards therapeutic applications of miRNAs, with encouraging results. Databases such as NCBI, PubMed, and Medline were searched for a selection of articles reporting the relationship between deregulated miRNAs and genetic aberrations used in the latest WHO CNS classification. The current review discussed the recommended molecular biomarkers and genetic aberrations based on the 2021 WHO classification in adult-type diffuse gliomas, along with associated deregulated miRNAs. Additionally, the study highlights miRNA-based treatment advancements in adults with gliomas.

miRNAs as potential game-changers in melanoma: A comprehensive review

Melanoma is the sixth most frequent malignancy. It represents 1.7% of all cancer cases worldwide. Many risk factors are associated with melanoma including ultraviolet radiation skin phenotype, Pigmented Nevi, Pesticides, and genetic and epigenetic factors. Of the main epigenetic factors affecting melanoma are microribonucleic acids (miRNAs). They are short nucleic acid chains that have the potential to prevent the expression of a number of target genes. They could target a number of genes related to melanoma initiation, stemness, angiogenesis, apoptosis, proliferation, and potential resistance to treatment. Additionally, they can control several melanoma signaling pathways, including P53, WNT/-catenin, JAK/STAT, PI3K/AKT/mTOR axis, TGF- β, and EGFR. MiRNAs also play a role in the resistance of melanoma to essential treatment regimens. The stability and abundance of miRNAs might be important factors enhancing the use of miRNAs as markers of prognosis, diagnosis, stemness, survival, and metastasis in melanoma patients.

Knockdown of lncRNA TP53TG1 Enhances the Efficacy of Sorafenib in Human Hepatocellular Carcinoma Cells

The multikinase inhibitor, sorafenib, is a first-line treatment for hepatocellular carcinoma (HCC), but its limited efficacy, drug resistance and toxicity are a concern. In this study, we investigated the role of lncRNA TP53TG1 in the efficacy of sorafenib in HCC cells. We found that treatment with sorafenib increased the expression of TP53TG1 in HCC cells. Knockdown of TP53TG1 sensitized tumor cells to the antiproliferative effects of sorafenib. Furthermore, TP53TG1 knockdown had an additive inhibitory effect on HCC cell proliferation and migration in the presence of sorafenib. The combination of TP53TG1 knockdown and sorafenib drastically inhibited the activation of the ERK pathway. This work demonstrates that TP53TG1 deficiency enhances the efficacy of sorafenib in HCC. Combining TP53TG1 knockdown with sorafenib may be an optimal form of therapy for HCC treatment.

Exosomal lncRNA TUG1 from cancer-associated fibroblasts promotes liver cancer cell migration, invasion, and glycolysis by regulating the miR-524-5p/SIX1 axis

Background

Increasing evidence suggests that taurine upregulated gene 1 (TUG1) is crucial for tumor progression; however, its role in hepatocellular carcinoma (HCC) and the underlying mechanisms are not well characterized.

Methods

The expression levels of TUG1, miR-524-5p, and sine oculis homeobox homolog 1 (SIX1) were determined using quantitative real-time PCR. The regulatory relationships were confirmed by dual-luciferase reporter assay. Cell proliferation and invasion were assessed using Cell Counting Kit 8 and transwell assays. Glucose uptake, cellular levels of lactate, lactate dehydrogenase (LDH), and adenosine triphosphate (ATP) were detected using commercially available kits. Silencing of TUG1 or SIX1 was performed by lentivirus transduction. Protein levels were measured by immunoblotting.

Results

Cancer-associated fibroblasts (CAFs)-secreted exosomes promoted migration, invasion, and glycolysis in HepG2 cells by releasing TUG1. The promotive effects of CAFs-secreted exosomes were attenuated by silencing of TUG1. TUG1 and SIX1 are targets of miR-524-5p. SIX1 knockdown inhibited the promotive effects of miR-524-5p inhibitor. Silencing of TUG1 suppressed tumor growth and lung metastasis and therefore increased survival of xenograft model mice. We also found that TUG1 and SIX1 were increased in HCC patients with metastasis while miR-524-5p was decreased in HCC patients with metastasis.

Conclusions

CAFs-derived exosomal TUG1 promoted migration, invasion, and glycolysis in HCC cells via the miR-524-5p/SIX1 axis. These findings may help establish the foundation for the development of therapeutics strategies and clinical management for HCC in future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00309-9.

Ginsenoside Rh2 inhibits thyroid cancer cell migration and proliferation via activation of miR-524-5p

INTRODUCTION

Thyroid cancer is an important disease that threatens the health of humans. Ginsenoside Rh2 is known as an anticancer molecule; however, its function in thyroid cancer cells has not been reported. In the present study, we identified that Rh2 treatment of the thyroid cancer cell line K1 inhibited cell migration and proliferation.

MATERIAL AND METHODS

We determined the Rh2 function in thyroid cancer cell lines. By RT-PCR, expression of miR-524-5p and related genes were determined. The cell phenotype including cell migration and proliferation were detected after serials treatment. The relevant protein level were checked by Western blot.

RESULTS

Interestingly, we observed that miR-524-5p, a type of miRNA, had lower expression in the thyroid cancer cell lines TPC-1, K1, and NPA than in the normal thyroid cell line Nthyri3-1. Additionally, Rh2 treatment induced miR-524-5p expression. Further examination using overexpression of miR-524-5p identified that the miR-524-5p mimic inhibited cell migration and proliferation of the K1 line. Similar to Rh2-treated cells, the miR-524-5p mimic-expressing cells had increased E-cadherin and reduced vimentin levels compared to the control cells. Next, we examined the relationship between Rh2 and miR-524-5p with respect to thyroid cell migration and proliferation. Treatment with Rh2 and miR-524-5p inhibitor suppressed Rh2 action on K1 thyroid cell migration and proliferation, and the rates were similar to those in control cells, suggesting that Rh2 might induce miR-524-5p expression to inhibit thyroid cancer cell migration and proliferation.

CONCLUSIONS

Our analyses identified Rh2 and miR-524-5p action on thyroid cancer cell migration and proliferation as well as the linkage between Rh2 and miR-524-5p in thyroid cancer cell development.

Cytokine storm in the pathophysiology of COVID-19: Possible functional disturbances of miRNAs

SARS-CoV-2, as the causative agent of COVID-19, is an enveloped positives-sense single-stranded RNA virus that belongs to the Beta-CoVs sub-family. A sophisticated hyper-inflammatory reaction named cytokine storm is occurred in patients with severe/critical COVID-19, following an imbalance in immune-inflammatory processes and inhibition of antiviral responses by SARS-CoV-2, which leads to pulmonary failure, ARDS, and death. The miRNAs are small non-coding RNAs with an average length of 22 nucleotides which play various roles as one of the main modulators of genes expression and maintenance of immune system homeostasis. Recent evidence has shown that Homo sapiens (hsa)-miRNAs have the potential to work in three pivotal areas including targeting the virus genome, regulating the inflammatory signaling pathways, and reinforcing the production/signaling of IFNs-I. However, it seems that several SARS-CoV-2-induced interfering agents such as viral (v)-miRNAs, cytokine content, competing endogenous RNAs (ceRNAs), etc. preclude efficient function of hsa-miRNAs in severe/critical COVID-19. This subsequently leads to increased virus replication, intense inflammatory processes, and secondary complications development. In this review article, we provide an overview of hsa-miRNAs roles in viral genome targeting, inflammatory pathways modulation, and IFNs responses amplification in severe/critical COVID-19 accompanied by probable interventional factors and their function. Identification and monitoring of these interventional elements can help us in designing the miRNAs-based therapy for the reduction of complications/mortality rate in patients with severe/critical forms of the disease.

Mesenchymal stem cell-derived exosomal miR-21a-5p promotes M2 macrophage polarization and reduces macrophage infiltration to attenuate atherosclerosis

Atherosclerosis (AS) is the main pathological basis for ischemic cardiovascular and cerebrovascular diseases. Mesenchymal stem cell (MSC)-derived exosomes have the potential to alleviate AS, while the underlying mechanism remains unclear. Here, we aimed to investigate the mechanism of MSC-derived exosomes in AS. The AS mouse model was prepared by feeding ApoE-/- mice with high-fat diet. AS mice were administered with MSC-derived exosomes, and the atherosclerotic plaque area was analyzed by Oil Red O staining. Mouse RAW264.7 macrophages were incubated with MSC-derived exosomes. The macrophage infiltration, macrophage proportion, and cell migration were estimated by immunohistochemistry, flow cytometry, or Transwell assay. The relationship between miR-21a-5p and kruppel-like factor 6 (KLF6) or extracellular signal-regulated protein kinases 2 (ERK2) was verified by luciferase reporter assay. We found that MSC-derived exosomes promoted M2 polarization of macrophages and reduced plaque area and macrophage infiltration in AS mice. miR-21a-5p overexpression caused an increase of M2 macrophages in RAW264.7 cells and led to a decrease in migration of RAW264.7 cells. Moreover, both KLF6 and ERK2 are the targets of miR-21a-5p. MSC-derived exosomes containing miR-21a-5p promoted M2 polarization of RAW264.7 cells by suppressing KLF6 expression. MSC-derived exosomes containing miR-21a-5p inhibited migration of RAW264.7 cells through inhibiting the ERK1/2 signaling pathway. In conclusion, MSC-derived exosomes containing miR-21a-5p promote macrophage polarization and reduce macrophage infiltration by targeting KLF6 and ERK1/2 signaling pathways, thereby attenuating the development of AS. Thus, MSC-derived exosomes may be a promising treatment for AS.

The impact of microRNAs on myeloid-derived suppressor cells in cancer

Inflammation promotes cancer development. To a large extent, this can be attributed to the recruitment of myeloid-derived suppressor cells (MDSCs) to tumors. These cells are known for establishing an immunosuppressive tumor microenvironment by suppressing T cell activities. However, MDSCs also promote metastasis and angiogenesis. Critically, as small non-coding RNAs that regulate gene expression, microRNAs (miRNAs) control MDSC activities. In this review, we discuss how miRNA networks regulate key MDSC signaling pathways, how they shape MDSC development, differentiation and activation, and how this impacts tumor development. By targeting the expression of miRNAs in MDSCs, we can alter their main signaling pathways. In turn, this can compromise their ability to promote multiple hallmarks of cancer. Therefore, this may represent a new powerful strategy for cancer immunotherapy.

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‑524‑5p regulates the proliferation and invasion of HTR‑8/SVneo trophoblasts by targeting NUMB in the Notch signaling pathway

Preeclampsia is a pregnancy disorder that is primarily associated with maternal and neonatal or fetal morbidity and mortality. The discovery of dysregulated microRNAs (miRs) and their roles in preeclampsia has provided new insight into the mechanisms involved in pregnancy‑related disorders. In the present study, quantitative PCR demonstrated that the expression levels of miR‑524‑5p were lower in patients with preeclampsia than those in normal pregnant women. Cell Counting Kit‑8 and Transwell assays indicated that overexpression of miR‑524‑5p promoted the proliferation and invasion of HTR‑8/SVneo cells, whereas inhibition of miR‑524‑5p suppressed HTR‑8/SVneo cell proliferation and invasion. Furthermore, NUMB endocytic adaptor protein (NUMB), a negative regulator of the Notch signaling pathway and a target gene of miR‑524‑5p, limited the effects of miR‑524‑5p on HTR‑8/SVneo cell invasion and migration. The present study demonstrated that miR‑524‑5p regulated the proliferation and invasion of HTR‑8/SVneo cells at least partly by targeting NUMB to regulate the Notch signaling pathway.

The Anticancer Effect of Inula viscosa Methanol Extract by miRNAs' Re-regulation: An in vitro Study on Human Malignant Melanoma Cells

Alternative and natural therapies are needed for malignant melanoma (MM), the most deadly skin cancer type due to chemotherapy's limited effect. In the present study, we evaluated the anticancer potentials of Inula viscosa methanol and water extracts (IVM and IVW) on MM cells, A2058 and MeWo, and normal fibroblasts. After the chromatographic and antioxidant activity analysis, their antiproliferative effects were determined with the increasing doses for 24-72 h. IVM induced more cell death in a dose and time-dependent manner in MM cells compared to IVW. This effect was probably due to the higher amount of phenolics in it. IVM significantly induced more apoptotic death in MM cells than fibroblasts (p < 0.01), which was also supported morphologically. IVM also caused cell cycle arrest at G0/G1 and G2/M phases in A2058 and MeWo, respectively, and suppressed the migration ability of MM cells (p < 0.01). Additionally, IVM was found to have significant potential in regulating MM-related miRNAs, upregulating miR-579 and miR-524, and downregulating miR-191 and miR-193, in MM cells (p < 0.05, p < 0.01). As a result, the anticancer effect of IVM via regulating miRNAs' expression has been demonstrated for the first time. Thus, IVM, with these potentials, may be a promising candidate for MM treatment.

miR-524-5p reduces the progression of the BRAF inhibitor-resistant melanoma

BRAF inhibitors were approved for the treatment of BRAF-mutant melanoma. However, most patients acquire the resistance to BRAF inhibitors after several months of treatment. miR-524-5p is considered as a tumor suppressor in many cancers, including melanoma. In this study, we investigated the biological functions of miR-524-5p in melanoma with acquired resistance to BRAF inhibitor and evaluated the endogenous miR-524-5p expression as a biomarker for melanoma. The results showed that the expression of miR-524-5p was 0.481-fold lower in melanoma tissues (n = 117) than in nevus tissues (n = 40). Overexpression of miR-524-5p significantly reduced proliferative, anchorage-independent growth, migratory and invasive abilities of BRAF inhibitor-resistant melanoma cells. Moreover, the introduction of miR-524-5p led to a reduced development of BRAF inhibitor-resistant melanoma in vivo. Remarkably, the MAPK/ERK signaling pathway was decreased after treatment with miR-524-5p. Furthermore, next-generation sequencing analysis implied that the complement system, leukocyte extravasation, liver X receptor/retinoid-X-receptor activation, and cAMP-mediated signaling may be related to miR-524-5p-induced pathways in the resistant cells. The miR-524-5p level was higher on average in complete response and long-term partial response patients than in progressive disease and short-term partial response patients treated with BRAF inhibitors. Our results proposed that miR-524-5p could be considered as a target for treatment BRAF inhibitor-resistant melanoma and a prognostic marker in the response of patients to BRAF inhibitors for melanoma.

MicroRNAs as regulators of ERK/MAPK pathway: A comprehensive review

The ERK/MAPK cascade is one the four distinctive MAPK cascades which transmit extracellular signals to intracellular targets. This cascade has an important role in the regulation of several fundamental processes such as proliferation, differentiation and cell response to diverse extrinsic stresses. Moreover, several studies have shown participation of this cascade in the pathogenesis of cancer. Recent investigations have unraveled interaction between microRNAs (miRNAs) and ERK/MAPK cascade. These transcripts reside in both upstream and downstream of this cascade, regulating or being regulated by ERK/MAPK proteins. In the current review, we summarize the role of miRNAs in the regulation of ERK/MAPK and their contribution in the pathogenesis of human disorders with particular focus on cancers.

Tumor Suppressor Role of hsa-miR-193a-3p and -5p in Cutaneous Melanoma

BACKGROUND

Remarkable deregulation of several microRNAs (miRNAs) is demonstrated in cutaneous melanoma. hsa-miR-193a-3p is reported to be under-expressed in tissues and in plasma of melanoma patients, but the role of both miR-193a arms in melanoma is not known yet.

METHODS

After observing the reduced levels of miR-193a arms in plasma exosomes of melanoma patients, the effects of hsa-miR-193a-3p and -5p transfection in cutaneous melanoma cell lines are investigated.

RESULTS

In melanoma cell lines A375, 501Mel, and MeWo, the ectopic over-expression of miR-193a arms significantly reduced cell viability as well as the expression of genes involved in proliferation (ERBB2, KRAS, PIK3R3, and MTOR) and apoptosis (MCL1 and NUSAP1). These functional features were accompanied by a significant downregulation of Akt and Erk pathways and a strong increase in the apoptotic process. Since in silico databases revealed TROY, an orphan member of the tumor necrosis receptor family, as a potential direct target of miR-193a-5p, this possibility was investigated using the luciferase assay and excluded by our results.

CONCLUSIONS

Our results underline a relevant role of miR-193a, both -3p and -5p, as tumor suppressors clarifying the intracellular mechanisms involved and suggesting that their ectopic over-expression could represent a novel treatment for cutaneous melanoma patients.

microRNA-524-5p inhibits proliferation and induces cell cycle arrest of osteosarcoma cells via targeting CDK6

BACKGROUND

Osteosarcoma (OS) is one of the most commonly diagnosed malignant tumors that mainly affects children and adolescents. The underlying molecular mechanisms that are responsible for the initiation and development of OS are still not clear. Increasing evidence suggested the tumor suppressor role of microRNA-524-5p in a variety of cancers via targeting key pathways involved in tumorigenesis. The aim of this study was to characterize the function of miR-524-5p in OS.

METHODS

A total 50 paired OS tissues and adjacent normal tissues were collected from OS patients. The expression of miR-524-5p in OS tissues and cells was detected by RT-qPCR. The CCK-8 assay, flow cytometry and transwell assay were applied to determine the proliferation and invasion abilities of OS cells. The targets of miR-524-5p were predicted using the miRDB dataset and confirmed by luciferase reporter assay and western blot analysis.

RESULTS

The expression of miR-524-5p was decreased in OS tissues and cell lines. OS patients with lymph node metastasis harbored relative lower level of miR-524-5p. Overexpression of miR-524-5p in OS cells significantly suppressed the proliferation, drove cell cycle arrest and apoptosis. The mechanism investigation revealed that miR-524-5p bound the 3'-untranslated region (UTR) of Cyclin Dependent Kinase 6 (CDK6) and repressed the expression of CDK6 in OS cells. Overexpressed CDK6 was found in OS tissues, which was inversely correlated with that of miR-524-5p. Moreover, forced expression of CDK6 significantly reversed the anti-cancer effects of miR-524-5p on the proliferation, apoptosis and cell cycle arrest of OS cells.

CONCLUSIONS

Our results identified the tumor-suppressive role of miR-524-5p in OS via targeting CDK6, which may lead to the identification of novel therapeutic target for the treatment of OS.

MicroRNAs as Key Players in Melanoma Cell Resistance to MAPK and Immune Checkpoint Inhibitors

Advances in the use of targeted and immune therapies have revolutionized the clinical management of melanoma patients, prolonging significantly their overall and progression-free survival. However, both targeted and immune therapies suffer limitations due to genetic mutations and epigenetic modifications, which determine a great heterogeneity and phenotypic plasticity of melanoma cells. Acquired resistance of melanoma patients to inhibitors of BRAF (BRAFi) and MEK (MEKi), which block the mitogen-activated protein kinase (MAPK) pathway, limits their prolonged use. On the other hand, immune checkpoint inhibitors improve the outcomes of patients in only a subset of them and the molecular mechanisms underlying lack of responses are under investigation. There is growing evidence that altered expression levels of microRNAs (miRNA)s induce drug-resistance in tumor cells and that restoring normal expression of dysregulated miRNAs may re-establish drug sensitivity. However, the relationship between specific miRNA signatures and acquired resistance of melanoma to MAPK and immune checkpoint inhibitors is still limited and not fully elucidated. In this review, we provide an updated overview of how miRNAs induce resistance or restore melanoma cell sensitivity to mitogen-activated protein kinase inhibitors (MAPKi) as well as on the relationship existing between miRNAs and immune evasion by melanoma cell resistant to MAPKi.

miR-410-3p is induced by vemurafenib via ER stress and contributes to resistance to BRAF inhibitor in melanoma

Despite significant development of melanoma therapies, death rates remain high. MicroRNAs, controlling posttranscriptionally gene expression, play role in development of resistance to BRAF inhibitors. The aim of the study was to assess the role of miR-410-3p in response to vemurafenib-BRAF inhibitor. FFPE tissue samples of 12 primary nodular melanomas were analyzed. With the use of Laser Capture Microdissection, parts of tumor, transient tissue, and adjacent healthy tissue were separated. In vitro experiments were conducted on human melanoma cell lines A375, G361, and SK-MEL1. IC50s of vemurafenib were determined using MTT method. Cells were transfected with miR-410-3p mimic, anti-miR-410-3p and their non-targeting controls. ER stress was induced by thapsigargin. Expression of isolated RNA was determined using qRT-PCR. We have found miR-410-3p is downregulated in melanoma tissues. Its expression is induced by vemurafenib in melanoma cells. Upregulation of miR-410-3p level increased melanoma cells resistance to vemurafenib, while its inhibition led to the decrease of resistance. Induction of ER stress increased the level of miR-410-3p. miR-410-3p upregulated the expression of AXL in vitro and correlated with markers of invasive phenotype in starBase. The study shows a novel mechanism of melanoma resistance. miR-410-3p is induced by vemurafenib in melanoma cells via ER stress. It drives switching to the invasive phenotype that leads to the response and resistance to BRAF inhibition.

LncRNA TTN-AS1 Regulates miR-524-5p and RRM2 to Promote Breast Cancer Progression

Background

Recent studies suggest many long non-coding RNAs (lncRNAs) are crucial oncogenes or tumor suppressors. This study intended to investigate the biological function and mechanism of lncRNA TTN antisense RNA 1 (TTN-AS1) in the progression of breast cancer (BC).

Materials and Methods

BC tissue samples were collected. The expression of TTN-AS1 in BC tissues and adjacent tissues was detected by qRT-PCR, and the relationship between pathological indicators and TTN-AS1 expression was analyzed by chi-square test. BC cell lines T47D and BT549 were utilized as cell models. CCK-8 assay and BrdU assay were used to detect the effect of TTN-AS1 on BC cell proliferation. Transwell assay was used to detect the effects of TTN-AS1 on cell migration and invasion. In addition, dual-luciferase reporter gene assay was used to confirm the targeting relationship between miR-524-5p and TTN-AS1. Western blot was used to detect the function of TTN-AS1 on regulating ribonucleotide reductase subunit 2 (RRM2) and survivin. Additionally, subcutaneous xenotransplanted tumor model and tail vein injection model were constructed in vivo.

Results

The expression of TTN-AS1 in BC tissues was significantly higher than that in normal tissues, and its high expression was correlated with adverse pathological indicators. Overexpression of TTN-AS1 significantly promoted the proliferation, migration and invasion of BC cells. TTN-AS1 knockdown suppressed the malignant phenotypes of BC cells. TTN-AS1 overexpression significantly impeded the expression of miR-524-5p, but increased the expression of RRM2.

Conclusion

TTN-AS1 exerts oncogenic function in BC by repressing miR-524-5p and increasing the expression of RRM2.

Long non-coding RNA SNHG7 promotes malignant melanoma progression through negative modulation of miR-9

Long non-coding small nucleolar RNA host gene 7 (lncRNA SNHG7) was verified to act as an onco-gene in human cancers. Nevertheless, the role of SNHG7 in malignant melanoma remains elusive. The present study showed an increase of SNHG7 expression in malignant melanoma tissues and cell lines. Besides, SNHG7 knockdown inhibited proliferation and migration in malignant melanoma cells. Bioinformatics analysis demonstrated that SNHG7 functions as a molecular sponge for miR-9 in biological behavior of melanoma cells. And miR-9 could inhibit the expression of PI3KR3 by binding with the 3'-UTR. Furthermore, PI3KR3, pAKT, cyclin D1 and Girdin expression was down-regulated after SNHG7 knockdown by siRNA. In addition, SNHG7 knockdown decreased xenograft growth in vivo. Taken together, this research demonstrated that SNHG7 was an oncogene in malignant melanoma, providing a novel insight for the pathogenesis and new potential therapeutic target for malignant melanoma.

LncRNA MSC-AS1 aggravates nasopharyngeal carcinoma progression by targeting miR-524-5p/nuclear receptor subfamily 4 group A member 2 (NR4A2)

Background

Nasopharyngeal carcinoma (NPC) is a subtype of head and neck cancer with dismal prognosis and high relapse rate. The role of long non-coding RNAs (lncRNAs) in NPC has become a research hotspot in recent years. This study aimed to interrogate the function and mechanism of lncRNA MSC antisense RNA 1 (MSC-AS1) in NPC.

Methods

MSC-AS1 level in NPC tissues and cells were detected by RT-qPCR. Function of MSC-AS1 in NPC cells was assessed by CCK-8, EdU, TUNEL, caspase-3 activity, and transwell invasion assay. Interaction of microRNA-524-5p (miR-524-5p) with MSC-AS1 and nuclear receptor subfamily 4 group A member 2 (NR4A2) was determined by RIP and luciferase reporter assays.

Results

MSC-AS1 was upregulated in NPC tissues and cells. Functional assays indicated that MSC-AS1 exacerbated cell proliferation, hindered apoptosis, and facilitated invasion and epithelial-to-mesenchymal transition (EMT) in NPC. Mechanistically, MSC-AS1 sequestered miR-524-5p to upregulate NR4A2 expression in NPC cells. Finally, NR4A2 was conformed as an oncogene in NPC, and overexpressed NR4A2 could restore MSC-AS1 knockdown-mediated inhibition on NPC progression.

Conclusions

Our study firstly showed that lncRNA MSC-AS1 aggravated NPC progression by sponging miR-524-5p to increase NR4A2 expression, indicating MSC-AS1 as a novel target for the lncRNA-targeted therapy in NPC.

MiR-524-5p Suppresses Migration, Invasion, and EMT Progression in Breast Cancer Cells Through Targeting FSTL1

Background: The effects of miR-524-5p on breast cancer (BC) have not been investigated, though studies show that miR-524-5p has an anticancer function. Thus, this study investigated the effects of miR-524-5p on BC cells and its potential molecular mechanism. Materials and Methods: The expression of miR-524-5p from the collected BC samples was determined. Cell counting kit-8 (CCK-8) assay was performed to examine the effect of miR-524-5p on BC cells viability. The target for miR-524-5p was predicted by bioinformatics and further verified by luciferase assay. Wound healing assay and transwell assay were performed to determine cell migration and invasion of BC cells. The expressions of Follistatin-like 1 (FSTL1) and related proteins in epithelial-mesenchymal transition (EMT) were detected by Western blotting and quantitative real-time polymerase chain reaction. Results: MiR-524-5p was low-expressed in BC samples, and upregulation of miR-524-5p suppressed BC cell viability, migration, and invasion. FSTL1 was predicted as a target for miR-524-5p. In addition, overexpressed FSTL1 effectively abolished the effect of miR-524-5p on inhibiting FSTL1 expression, and reversed the inhibitory effects of miR-524-5p on the migration, invasion of BC cells as well as the effect of miR-524-5p on regulating the expressions of matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), E-cadherin, and N-cadherin. Conclusions: Our findings suggest that miR-524-5p targeting FSTL1 adversely affects the progression of migration, invasion, and EMT of BC cells, thus, miR-524-5p is possibly a target for BC treatment.

miR-524-5p inhibits angiogenesis through targeting WNK1 in colon cancer cells

There is increasing evidence that microRNA (miRNA) abnormity is involved in the occurrence and the development of various malignancies, including colon cancer. MiRNA-524-5p has been reported to possess anticancer activity in various tumors, which function is seldom investigated in colon cancer cells. The aim of this study was to explore the effect of the miRNA-524-5p/with-no-lysine kinase 1 (WNK1) system on angiogenesis in a colon cancer cell line (HT-29 and COLO205 cells) and further investigate the potential mechanisms. We found miRNA-524-5p expression was relatively high in COLO205 cells and relatively low in HT-29 cells. Elevating miRNA-524-5p expression inhibited proliferation, induced cycle arrest, diminished vascular endothelial growth factor production, and thereby suppressed angiogenesis in HT-29 cells. WNK1 silencing exerted the ability of antiangiogenesis in HT-29 cells. Besides, miRNA-524-5p deficiency-induced angiogenesis was impeded by WNK1 silence in COLO205 cells. In a murine tumor model, miRNA-524-5p agomir treatment significantly suppressed colon cancer tumorigenicity with the downregulation of WNK1 expression. In summary, our results indicated that miRNA-524-5p inhibited angiogenesis in colon cancer cells via targeting WNK1.NEW & NOTEWORTHY MiRNA-524-5p inhibited angiogenesis in colon cancer cells via targeting with-no-lysine kinase 1.

The miRNAs Role in Melanoma and in Its Resistance to Therapy

Melanoma is the less common but the most malignant skin cancer. Since the survival rate of melanoma metastasis is about 10–15%, many different studies have been carried out in order to find a more effective treatment. Although the development of target-based therapies and immunotherapeutic strategies has improved chances for patient survival, melanoma treatment still remains a big challenge for oncologists. Here, we collect recent data about the emerging role of melanoma-associated microRNAs (miRNAs) currently available treatments, and their involvement in drug resistance. We also reviewed miRNAs as prognostic factors, because of their chemical stability and resistance to RNase activity, in melanoma progression. Moreover, despite miRNAs being considered small conserved regulators with the limitation of target specificity, we outline the dual role of melanoma-associated miRNAs, as oncogenic and/or tumor suppressive factors, compared to other tumors.

Circulatory miRNA-484, 524, 615 and 628 expression profiling in HCV mediated HCC among Egyptian patients; implications for diagnosis and staging of hepatic cirrhosis and fibrosis

Circulatory microRNAs have recently emerged as non-invasive and effective biomarkers for diagnosis of various diseases. Currently there is no reliable biomarker for diagnosis, prognosis or even staging of fibrotic and cirrhotic complications arising from HCV infection. This study aimed at investigating plasma miR-484, miR-524, miR-615-5p and miR-628-3p expression signatures in Egyptian patients with HCV mediated cirrhosis, fibrosis and HCC. Plasma miRNAs expressions in 168 samples [(40 healthy controls, 47 with HCV liver fibrosis, 40 with HCV-cirrhosis and 41 with HCV-hepatocellular carcinoma (HCC)] were quantified using RT-PCR. The studied miRNAs were differentially expressed among all participating groups. Plasma miR-484 levels exhibited significant downregulation in advanced fibrosis as compared to mild fibrosis and HCC. Moreover, miR-484 showed significant upregulation in HCC versus cirrhosis. Both miR-524-5p and miR-615-5p were upregulated in cirrhotic group as compared to controls. Differential expression between HCC and controls was noticeable in miR-524-5p. Receiver operator characteristic curve analysis revealed promising diagnostic performance for miR-484 in discriminating late fibrosis from both mild fibrosis and HCC and also for miR-524 in distinguishing between cirrhosis and fibrosis. In conclusion, investigated miRNAs could serve as potential and sensitive biomarkers for staging, prognosis and early diagnosis of various HCV mediated hepatic disease progression.

MiR-145: a potential biomarker of cancer migration and invasion

MircoRNAs (miRNAs) are a diverse family of highly-conserved small non-coding RNAs, which range from approximately 18 to 25 nucleotides in size. They regulate gene expression transcriptionally or post-transcriptionally via binding to the 3'-untranslated region (3'-UTR) of target message RNAs (mRNAs). MiRNAs have emerged as molecular regulators that participate in physiological and pathological processes of diverse malignancies. Among them, miRNA-145 (miR-145) played a profound role in tumorigenesis and progression of various neoplasms. In this review, we summarized the recent findings regarding miR-145, to elucidate its functional roles in cell invasion and migration of diverse human malignancies, and considered it a potential biomarker for cancer diagnosis, screening, and prognosis.

The Importance of microRNAs in RAS Oncogenic Activation in Human Cancer

microRNAs (miRNAs) regulate gene expression by modulating the translation of protein-coding RNAs. Their aberrant expression is involved in various human diseases, including cancer. Here, we summarize the experimental pieces of evidence that proved how dysregulated miRNA expression can lead to RAS (HRAS, KRAS, or NRAS) activation irrespective of their oncogenic mutations. These findings revealed relevant pathogenic mechanisms as well as mechanisms of resistance to target therapies. Based on this knowledge, potential approaches for the control of RAS oncogenic activation can be envisioned.

Systematic evaluation of the microRNAome through miR-CATCHv2.0 identifies positive and negative regulators of BRAF-X1 mRNA

Here we present miR-CATCHv2.0, an implemented experimental method that allows the identification of the microRNA species directly bound to an RNA of interest. After cross-linking of microRNA::RNA::Ago2 complexes using formaldehyde, the RNA is fragmented using sonication and then subjected to affinity purification using two sets of biotinylated tiling probes (ODD and EVEN). Finally, enriched microRNA species are retrieved by means of small RNA sequencing coupled with an ad hoc analytical workflow. In BRAFV600E mutant A375 melanoma cells, miR-CATCHv2.0 allowed us to identify 20 microRNAs that target X1, the most abundant isoform of BRAF mRNA. These microRNAs fall into different functional classes, according to the effect that they exert (decrease/increase in BRAFV600E mRNA and protein levels) and to the mechanism they use to achieve it (destabilization/stabilization of X1 mRNA or decrease/increase in its translation). microRNA-induced variations in BRAFV600E protein levels are most of the times coupled to consistent variations in pMEK levels, in melanoma cell proliferation in vitro and in sensitivity to the BRAF inhibitor vemurafenib in a xenograft model in zebrafish. However, microRNAs exist that uncouple the degree of activation of the ERK pathway from the levels of BRAFV600E protein. Our study proposes miR-CATCHv2.0 as an effective tool for the identification of direct microRNA-target interactions and, by using such a tool, unveils the complexity of the post-transcriptional regulation to which BRAFV600E and the ERK pathway are subjected in melanoma cells.

MicroRNA-524-5p suppresses the progression of papillary thyroid carcinoma cells via targeting on FOXE1 and ITGA3 in cell autophagy and cycling pathways

MicroRNAs are beneficial for cancer therapy as they can simultaneously downregulate multiple targets involved in diverse biological pathways related to tumor development. In papillary thyroid cancer, many microRNAs were identified as differentially expressed factors in tumor tissues. In another way, recent studies revealed cell proliferation, cell cycling, apoptosis, and autophagy are critical pathways controlling papillary thyroid cancer development and progression. As miR‐524‐5p was approved as a cancer suppressor targeting multiple genes in several types of cancer cells, this study aims to characterize the role of miR‐524‐5p in the thyroid cancer cell. The expression of miR‐524‐5p was decreased in the papillary thyroid cancer tissues and cell lines, while forkhead box E1 (FOXE1) and ITGA3 were increased. In the clinical case, expression of miR‐524‐5p, FOXE1, and ITGA3 were significantly correlated with papillary thyroid cancer development and progression. FOXE1 and ITGA3 were approved as direct targets of miR‐524‐5p. miR‐524‐5p could inhibit papillary thyroid cancer cell viability, migration, invasion, and apoptosis through targeting FOXE1 and ITGA3. Cell cycling and autophagy pathways were disturbed by downregulation of FOXE1 and ITGA3, respectively. Collectively, miR‐524‐5p targeting on FOXE1 and ITGA3 prevents thyroid cancer progression through different pathways including cell cycling and autophagy.

The potential of BRAF-associated non-coding RNA as a therapeutic target in melanoma

INTRODUCTION

The advent of targeted therapies and immune checkpoints inhibitors has enhanced the treatment of metastatic melanomas. Despite striking improvements of patients' survival, drug resistance continues to limit the efficacy of such treatments. Genetic and nongenetic/adaptive mechanisms of resistance could be involved; in the latter mechanism, noncoding RNAs (ncRNAs) are emerging as key players. Areas covered: This article outlines the current knowledge of ncRNA involvement in BRAF-mutant melanomas and the development of resistance to targeted/immunotherapies. We also discuss how ncRNAs can be exploited for the development of therapeutic and diagnostic approaches. Expert opinion: ncRNAs can be envisaged as powerful diagnostics and therapeutics. Despite progress in our knowledge about their deregulation in cancer, it is still difficult to derive universal and robust ncRNAs unique signatures of malignancy for diagnostic purposes, which need validation in large cohort of patients. Also, ncRNA specific targeting to melanoma cells in vivo requires the development of improved systemic delivery tools. In this regard, the development of stable nanodelivery particles seems to offer renewed hope for success in the clinic.

microRNA expression pattern as an ancillary prognostic signature for radiotherapy

Background

In view of the limited knowledge of plasma biomarkers relating to cancer resistance to radiotherapy, we have set up screening, training and testing stages to investigate the microRNAs (miRNAs) expression profile in plasma to predict between the poor responsive and responsive groups after 6 months of radiotherapy.

Methods

Plasma was collected prior to and after radiotherapy, and the microRNA profiles were analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) arrays. Candidate miRNAs were validated by single qRT-PCR assays from the training and testing set. The classifier for ancillary prognosis was developed by multiple logistic regression analysis to correlate the ratios of miRNAs expression levels with clinical data.

Results

We revealed that eight miRNAs expressions had significant changes after radiotherapy and the expression levels of miR-374a-5p, miR-342-5p and miR-519d-3p showed significant differences between the responsive and poor responsive groups in the pre-radiotherapy samples. The Kaplan–Meier curve analysis also showed that low miR-342-5p and miR-519d-3p expressions were associated with worse prognosis. Our results revealed two miRNA classifiers from the pre- and post-radiotherapy samples to predict radiotherapy response with area under curve values of 0.8923 and 0.9405.

Conclusions

The expression levels of miR-374a-5p, miR-342-5p and miR-519d-3p in plasma are associated with radiotherapy responses. Two miRNA classifiers could be developed as a potential non-invasive ancillary tool for predicting patient response to radiotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1711-4) contains supplementary material, which is available to authorized users.

Exploring major signaling cascades in melanomagenesis: a rationale route for targetted skin cancer therapy

Although most melanoma cases may be treated by surgical intervention upon early diagnosis, a significant portion of patients can still be refractory, presenting low survival rates within 5 years after the discovery of the illness. As a hallmark, melanomas are highly prone to evolve into metastatic sites. Moreover, melanoma tumors are highly resistant to most available drug therapies and their incidence have increased over the years, therefore leading to public health concerns about the development of novel therapies. Therefore, researches are getting deeper in unveiling the mechanisms by which melanoma initiation can be triggered and sustained. In this context, important progress has been achieved regarding the roles and the impact of cellular signaling pathways in melanoma. This knowledge has provided tools for the development of therapies based on the intervention of signal(s) promoted by these cascades. In this review, we summarize the importance of major signaling pathways (mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)-Akt, Wnt, nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB), Janus kinase (JAK)-signal transducer and activator of transcription (STAT), transforming growth factor β (TGF-β) and Notch) in skin homeostasis and melanoma progression. Available and developing melanoma therapies interfering with these signaling cascades are further discussed.

(Arg)9-SH2 superbinder: a novel promising anticancer therapy to melanoma by blocking phosphotyrosine signaling

Background

Melanoma is a malignant tumor with high misdiagnosis rate and poor prognosis. The bio-targeted therapy is a prevailing method in the treatment of melanoma; however, the accompanying drug resistance is inevitable. SH2 superbinder, a triple-mutant of the Src Homology 2 (SH2) domain, shows potent antitumor ability by replacing natural SH2-containing proteins and blocking multiple pY-based signaling pathways. Polyarginine (Arg)₉, a powerful vector for intracellular delivery of large molecules, could transport therapeutic agents across cell membrane. The purpose of this study is to construct (Arg)₉-SH2 superbinder and investigate its effects on melanoma cells, expecting to provide potential new approaches for anti-cancer therapy and overcoming the unavoidable drug resistance of single-targeted antitumor agents.

Methods

(Arg)₉ and SH2 superbinder were fused to form (Arg)₉-SH2 superbinder via genetic engineering. Pull down assay was performed to identify that (Arg)₉-SH2 superbinder could capture a wide variety of pY proteins. Immunofluorescence was used to detect the efficiency of (Arg)₉-SH2 superbinder entering cells. The proliferation ability was assessed by MTT and colony formation assay. In addition, wound healing and transwell assay were performed to evaluate migration of B16F10, A375 and A375/DDP cells. Moreover, apoptosis caused by (Arg)₉-SH2 superbinder was analyzed by flow cytometry-based Annexin V/PI. Furthermore, western blot revealed that (Arg)₉-SH2 superbinder influenced some pY-related signaling pathways. Finally, B16F10 xenograft model was established to confirm whether (Arg)₉-SH2 superbinder could restrain the growth of tumor.

Results

Our data showed that (Arg)₉-SH2 superbinder had the ability to enter melanoma cells effectively and displayed strong affinities for various pY proteins. Furthermore, (Arg)₉-SH2 superbinder could repress proliferation, migration and induce apoptosis of melanoma cells by regulating PI3K/AKT, MAPK/ERK and JAK/STAT signaling pathways. Importantly, (Arg)₉-SH2 superbinder could significantly inhibit the growth of tumor in mice.

Conclusions

(Arg)₉-SH2 superbinder exhibited high affinities for pY proteins, which showed effective anticancer ability by replacing SH2-containing proteins and blocking diverse pY-based pathways. The remarkable ability of (Arg)₉-SH2 superbinder to inhibit cancer cell proliferation and tumor growth might open the door to explore the SH2 superbinder as a therapeutic agent for cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0812-5) contains supplementary material, which is available to authorized users.

Upregulation of microRNA-524-5p enhances the cisplatin sensitivity of gastric cancer cells by modulating proliferation and metastasis via targeting SOX9

Cisplatin-based chemotherapy is the most commonly used treatment regimen for gastric cancer (GC), however, the resistance to cisplatin represents the key limitation for the therapeutic efficacy. Aberrant expression of MiR-524-5p appears to be involves in tumorigenesis and chemoresistance. However, the mechanism by which miR-524-5p mediates effects of cisplatin treatment in GC remains poorly understood. Expressions of MiR-524-5p was detected in GC tissues and cell lines by qRT-PCR. Cell proliferation was observed by MTT assay; Cell migration was detected by transwell migration and invasion assay. The targeting protein of miR-524-5p was identified by luciferase reporter assay and western blot. We found that downregulation of miR-524-5p in GC tissues and cell lines. SC-M1 and AZ521 cells resistant to cisplatin expressed low levels of miR-524-5p in comparison to the sensitive parental cells. Overexpression of miR-524-5p expression in SC-M1 and AZ521 cells inhibited cell proliferation, migration, and invasion, and conferred sensitivity to cisplatin-resistant GC cells. Subsequently, we identified SOX9 as a functional target protein of miR-524-5p and found that SOX9 overexpression could counteracts the chemosensitizing effects of miR-524-5p. These results provide novel insight into the regulation of GC tumorigenesis and progression by miRNAs. Restoration of miR-524-5p may have therapeutic potential against GC.

Reduced miR-550a-3p leads to breast cancer initiation, growth, and metastasis by increasing levels of ERK1 and 2

Hyperactivation of the Ras/ERK pathway contributes to breast cancer initiation and progression, and recent evidence suggests aberrant signaling of miRNAs that regulate the Ras/ERK pathway play important roles during carcinogenesis and cancer progression. In this study, we demonstrate that miR-550a-3p expression is negatively correlated with levels of ERK1 and ERK2, two pivotal effectors in the Ras/ERK pathway. MiR-550a-3p gradually decreased during breast cancer initiation and progression and this reduction was a prognostic indicator of poorer overall survival (OS) and disease-free survival (DFS) among breast cancer patients. Our mechanistic studies demonstrated that miR-550a-3p exerts its tumor-suppressor role by directly repressing ERK1 and ERK2 protein expression, thereby suppressing the oncogenic ERK/RSK cascades, which reduced breast cancer cell viability, survival, migration, invasion, tumorigenesis, and metastasis. The inhibitory effects of miR-550a-3p were rescued by ectopic expression of ERK1 and/or ERK2. The novel connection between miR-550a-3p and ERK defines a new diagnostic and prognostic role for miR-550a-3p and highlights ERK inhibition as a candidate therapeutic target for breast cancers exhibiting hyperactivated Ras/ERK signaling.

RAS-MAPK pathway epigenetic activation in cancer: miRNAs in action

The highly conserved RAS-mitogen activated protein kinase (MAPK) signaling pathway is involved in a wide range of cellular processes including differentiation, proliferation, and survival. Somatic mutations in genes encoding RAS-MAPK components frequently occur in many tumors, making the RAS-MAPK a critical pathway in human cancer. Since the pioneering study reporting that let-7 miRNA acted as tumor suppressor by repressing the RAS oncogene, growing evidence has suggested the importance of miRNAs targeting the RAS-MAPK in oncogenesis. MiRNAs alterations in human cancers may act as a rheostat of the oncogenic RAS signal that is often amplified as cancers progress. However, specific mechanisms leading to miRNAs deregulation and their functional consequences in cancer are far from being fully elucidated. In this review, we provide an experimental-validated map of RAS-MAPK oncomiRs and tumor suppressor miRNAs from transmembrane receptor to downstream ERK proteins. MiRNAs could be further considered as potential genetic biomarkers for diagnosis, prognosis, or therapeutic purpose.

miR-596 Modulates Melanoma Growth by Regulating Cell Survival and Death

Tumors grow because cancer cells lack the ability to balance cell survival and death signaling pathways. miR-596, a microRNA located at the 8p23.3 locus, has been shown by the TCGA-Assembler to be deleted in a significant number of melanoma samples. Here, we also validated the low levels of miR-596 in melanoma compared to tissue nevi, and Kaplan-Meier curve analysis revealed that low miR-596 expression was associated with worse overall survival. Moreover, we showed that miR-596 overexpression effectively inhibited MAPK/ERK signaling, cell proliferation, migration, and invasion and increased the cell apoptosis of melanoma cells. In addition, we found that miR-596 directly targets MEK1 and two apoptotic proteins, MCL1, and BCL2L1, in melanoma cells. Our findings indicated that miR-596 is an important miRNA that both negatively regulates the MAPK/ERK signaling pathway by targeting MEK1 and modulates the apoptosis pathway by targeting MCL1 and BCL2L1, suggesting that miR-596 could be a therapeutic candidate for treating melanoma, and a prognostic factor for melanoma patients.

EZH2 alteration driven by microRNA-524-5p and microRNA-324-5p promotes cell proliferation and temozolomide resistance in glioma

Recent data have been shown that EZH2 is a critical oncogene via the repression of tumor suppressor genes in human cancers. In our study, we performed a genome-wide miRNA screen with a bioinformatics analysis to identify EZH2 specific miRNAs. Of these miRNAs, miR-524-5p and miR-324-5p were decreased in glioma tissues, and confered poor prognosis for glioma patients. Upregulation of miR-524-5p and miR-324-5p reduced glioma cell proliferation and increased temozolomide (TMZ) chemosensitivity by targeting EZH2. Importantly, the effection of miR-524-5p and miR-324-5p on cell proliferation and TMZ chemosensitivity in glioma were reversed by expression of EZH2 cDNA. Further, miR-524-5p and miR-324-5p overexpression suppressed glioma growth and prolonged survival in an intracranial xenograft model. Multivariate Cox regression analysis revealed that miR-524-5p was an independent prognostic factor in gliobalstoma patients. Taken together, these data indicate that miRNA-driven EZH2 repression may provide evidence of the molecular mechanism for gliomagenesis and the novel therapeutic targets for glioma.

MicroRNAs in melanoma development and resistance to target therapy

microRNAs constitute a complex class of pleiotropic post-transcriptional regulators of gene expression involved in the control of several physiologic and pathologic processes. Their mechanism of action is primarily based on the imperfect matching of a seed region located at the 5′ end of a 21-23 nt sequence with a partially complementary sequence located in the 3′ untranslated region of target mRNAs. This leads to inhibition of mRNA translation and eventually to its degradation. Individual miRNAs are capable of binding to several mRNAs and several miRNAs are capable of influencing the function of the same mRNAs. In recent years networks of miRNAs are emerging as capable of controlling key signaling pathways responsible for the growth and propagation of cancer cells. Furthermore several examples have been provided which highlight the involvement of miRNAs in the development of resistance to targeted drug therapies. In this review we provide an updated overview of the role of miRNAs in the development of melanoma and the identification of the main downstream pathways controlled by these miRNAs. Furthermore we discuss a group of miRNAs capable to influence through their respective up- or down-modulation the development of resistance to BRAF and MEK inhibitors.

MiR-143 inhibits endometrial cancer cell proliferation and metastasis by targeting MAPK1

Endometrial cancer (EC) is one of the most commonly diagnosed gynecologic malignancies in the world, with the morbidity rate of over 7%. The mechanism of the pathogenesis has not been specifically elucidated to date, which is imperative for EC treatment. The aim of our study was to investigate the target relationship between miR-143 and mitogen-activated protein kinase 1 (MAPK1) and explore the effect of miR-143 on the endometrial cancers (EC) cells through targeting MAPK1. We collected EC tissues and adjacent tissues, and transfected miR-143 mimics and MAPK1 siRNA into EC cells with lipofectamine. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot were used to examine the expression of miR-143 and MAPK1 mRNA and the protein expression of MAPK1. Cell counting kit-8, wound healing assay, flow cytometry and transwell assay were applied to examining the alteration of the proliferation, migration, cell cycle and invasion ability of EC cells. We predicted the targeting gene of miR-143 through bioinformatics analysis. MiR-143 was found under-expressed in EC tissues and cells. Overexpression of miR-143 or knockdown of MAPK1 in human EC cell line HEC-1B inhibited the EC cell proliferation, migration and invasion and induced apoptosis. MAPK1 was verified to be a target gene of miR-143. MiR-143 overexpression could effectively inhibit mRNA and protein expression of MAPK1 in HEC-1B cells. Collectively, miR-143 might inhibit the proliferation, migration and invasion of EC cells, and promote the apoptosis of EC cells by suppressing MAPK1. These findings provided a view for new and potential therapeutic method for the clinical treatment of EC.

EGFR/c-myc axis regulates TGFβ/Hippo/Notch pathway via epigenetic silencing miR-524 in gliomas

The epidermal growth factor receptor (EGFR) frequently undergoes high-level genomic amplification and variant III (vIII) deletion in adult glioblastoma. MicroRNAs (miRNAs) are recognized to participate in gene expression regulation. We found that miR-524-3p and miR-524-5p were suppressed in the classical molecular subtype of glioblastoma (GBM) from Chinese Glioma Genome Atlas (CGGA) data, and the suppression was associated with EGFR overexpression and EGFRvIII mutation. These two miRNAs improved overall survival time of patients with glioma, and their overexpression could restrain glioma cell migration, proliferation, and cell cycle, and control tumor formation in vivo. Interestingly, both of the miRNAs had a synergistic inhibitory effect on glioma cells. Furthermore, we confirmed that EGFR amplification/EGFRvIII mutation can repress the expression of Pri-miR-524 by histone modification. MiR-524-3p and miR-524-5p inhibited TGF/β, Notch and the Hippo pathway by targeting Smad2, Hes1 and Tead1, respectively; these pathways repressed their common downstream transcription factor, C-myc. More interestingly, C-myc bound to the promoter region of EGFR/EGFRvIII and activated its expression. These findings indicate that miR-524 mediates the EGFR/EGFRvIII stimulating effect. It may serve as a potential therapeutic agent and classical-specific biomarker for the development of glioma.

MicroRNA-driven deregulation of cytokine expression helps development of drug resistance in metastatic melanoma

microRNAs are major components of the eukaryotic post-transcriptional machinery and are frequently deregulated during cancer development. Increasing evidence points to them also as key players in the establishment of drug resistance. In this review, we provide an updated overview of the role of miRNAs in melanoma development and drug resistance and postulate that they are able to drive these processes in concert with deregulation of inflammatory and angiogenic cytokine expression. Notably, we have identified by querying the Cancer Genome Atlas database, a defined set of miRNAs which mostly have an impact on the development of melanoma and have recognized the main downstream pathways controlled by them. Most importantly, these miRNAs, which are down-regulated in metastatic melanomas as compared to primary tumors, are also able to predict prognosis of BRAF-mutated melanoma patients. Finally, we discuss the possibility that a common miRNA signature characterizes not only acquired resistance to MAPKi but also innate resistance to anti-PD-1 immunotherapy, since these conditions are both associated with alterations of the same pro-angiogenetic and pro-inflammatory pathways.

Identification of plasma microRNAs as new potential biomarkers with high diagnostic power in human cutaneous melanoma

Melanoma is a devastating disease with few therapeutic options in the advanced stage and with the urgent need of reliable biomarkers for early detection. In this context, circulating microRNAs are raising great interest as diagnostic biomarkers. We analyzed the expression profiles of 21 selected microRNAs in plasma samples from melanoma patients and healthy donors to identify potential diagnostic biomarkers. Data analysis was performed using global mean normalization and NormFinder algorithm. Linear regression followed by receiver operating characteristic analyses was carried out to evaluate whether selected plasma miRNAs were able to discriminate between cases and controls. We found five microRNAs that were differently expressed among cases and controls after Bonferroni correction for multiple testing. Specifically, miR-15b-5p, miR-149-3p, and miR-150-5p were up-regulated in plasma of melanoma patients compared with healthy controls, while miR-193a-3p and miR-524-5p were down-regulated. Receiver operating characteristic analyses of these selected microRNAs provided area under the receiver operating characteristic curve values ranging from 0.80 to 0.95. Diagnostic value of microRNAs is improved when considering the combination of miR-149-3p, miR-150-5p, and miR-193a-3p. The triple classifier had a high capacity to discriminate between melanoma patients and healthy controls, making it suitable to be used in early melanoma diagnosis.

Effects of miR-145-5p through NRAS on the cell proliferation, apoptosis, migration, and invasion in melanoma by inhibiting MAPK and PI3K/AKT pathways

We aimed to detect the effects of miR-145-5p on the cell proliferation, apoptosis, migration, and invasion in NRAS-mutant, BRAF-mutant, and wild-type melanoma cells, in order to figure out the potential mechanisms and provide a novel therapeutic target of melanoma. RT-qPCR and western blot were used to detect the expression of miR-145-5p and NRAS in melanoma tumor tissues and cells, respectively. Luciferase assay was performed to determine whether miR-145-5p directly targeted NRAS. After transfecting miR-145-5p mimics, miR-145-5p inhibitors, NRAS cDNA and NRAS siRNA into CHL-1, VMM917 and SK-mel-28 cells, functional assays were used to detect the proliferation, apoptosis, invasion and migration, including MTT, flow cytometry, Transwell and wound healing assays. In addition, xenograft models in nude mice were also conducted to verify the role of miR-145-5p in vivo. MiR-145-5p was able to suppress proliferation, invasion, and migration of VMM917 and CHL-1 cells and induce apoptosis by inhibiting MAPK and PI3K/AKT pathways. However, aberrant expression of miR-145-5p and NRAS has little impact on the viability and metastasis of BRAF-mutant melanoma. The higher expression of miR-145-5p in xenograft models repressed the VMM917-induced and CHL-1-induced tumor growth observably and has little effect on SK-mel-28-induced tumor growth which was consistent with the results in vitro. Through targeting NRAS, miR-145-5p could suppress cell proliferation, invasion, and migration and induce apoptosis of CHL-1 and VMM917 melanoma cells by inhibiting MAPK and PI3K/AKT pathways.

MiR-20b Displays Tumor-Suppressor Functions in Papillary Thyroid Carcinoma by Regulating the MAPK/ERK Signaling Pathway

BACKGROUND

MicroRNAs (miRNAs) are endogenous, small, non-coding RNAs that play important roles in multiple biological processes. MiR-20b has been reported to be dysregulated in papillary thyroid carcinoma (PTC). However, the functional roles are still largely unknown. This study aimed to investigate the biological functions and the underlying molecular mechanisms of miR-20b in PTC.

METHOD

The expression of miR-20b was assessed by quantitative reverse transcription polymerase chain reaction in 47 pairs of PTC and adjacent normal thyroid tissues. The association between miR-20b expression and clinicopathologic status of PTC patients was analyzed. MiR-20b was overexpressed in the PTC cell lines K1 and TPC-1, and the effects on cell viability, migration, and invasion were evaluated. The study further searched for targets of miR-20b, and identified the possible molecular mechanisms of miR-20b in PTC cells. Additionally, the effect of miR-20b on tumor growth in nude mice was assessed.

RESULTS

It was found that miR-20b was markedly downregulated in PTC tissues compared with their adjacent normal thyroid tissues. The low-level expression of miR-20b was correlated with cervical lymph node metastasis and TNM staging. Upregulation of miR-20b inhibited cell viability, migration, and invasion in K1 and TPC-1 cells. Ectopic overexpression of miR-20b could suppress the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway through directly targeting son of sevenless homolog 1 (SOS1) and extracellular signal-regulated kinase 2 (ERK2). Furthermore, depletion of SOS1 or ERK2 by siRNAs has similar effects as miR-20b overexpression on cell viability and invasion, whereas rescued SOS1 or ERK2 expression partially reversed the inhibitory effects of miR-20b in TPC cell lines. In xenograft animal experiments, it was found that overexpressed miR-20b could suppress tumor growth of PTC cells.

CONCLUSION

These results indicate for the first time that miR-20b displays tumor-suppressor functions in PTC. By targeting SOS1 and ERK2, miR-20b inhibits the activity of the MAPK/ERK signaling pathway. The findings suggest that miR-20b may play an important role in PTC initiation, progression, and metastasis, and may provide a potential therapeutic target for PTC.