miR-125b induces cellular senescence in malignant melanoma

Non-coding RNAs' function in cancer development, diagnosis and therapy

While previous research on cancer biology has focused on genes that code for proteins, in recent years it has been discovered that non-coding RNAs (ncRNAs)play key regulatory roles in cell biological functions. NcRNAs account for more than 95% of human transcripts and are an important entry point for the study of the mechanism of cancer development. An increasing number of studies have demonstrated that ncRNAs can act as tumor suppressor genes or oncogenes to regulate tumor development at the epigenetic level, transcriptional level, as well as post-transcriptional level. Because of the importance of ncRNAs in cancer, most clinical trials have focused on ncRNAs to explore whether ncRNAs can be used as new biomarkers or therapies. In this review, we focus on recent studies of ncRNAs including microRNAs (miRNAs), long ncRNAs (lncRNAs), circle RNAs (circRNAs), PIWI interacting RNAs (piRNAs), and tRNA in different types of cancer and explore the application of these ncRNAs in the development of cancer and the identification of relevant therapeutic targets and tumor biomarkers. Graphical abstract drawn by Fidraw.

Tumour-derived extracellular vesicle based vaccines for melanoma treatment

The interest of extracellular vesicles (EVs) in cancer immunotherapy is increasing every day. EVs are lipid bilayer vesicles released by most cells, which contain the molecular signature of their parent cell. Melanoma-derived EVs present antigens specific to this aggressive type of cancer, but they also exert immunomodulatory and pro-metastatic activity. Until now, most reviews focus on the immunoevasive characteristics of tumour-derived EVs, but do not help to overcome the issues related to them. In this review, we describe isolation methods of EVs from melanoma patients and most interesting markers to oversee their effect if they are used as antigen carriers. We also discuss the methods developed so far to overcome the lack of immunogenicity of melanoma-derived EVs, which includes EV modification or adjuvant co-administration. In summary, we conclude that EVs can be an interesting antigen source for immunotherapy development once EV obtaining is optimised and the understanding of the mechanisms behind their multiple effects is further understood.

MicroRNA as a Diagnostic Tool, Therapeutic Target and Potential Biomarker in Cutaneous Malignant Melanoma Detection—Narrative Review

Melanoma is the most serious type of skin cancer, causing a large majority of deaths but accounting for only ~1% of all skin cancer cases. The worldwide incidence of malignant melanoma is increasing, causing a serious socio-economic problem. Melanoma is diagnosed mainly in young and middle-aged people, which distinguishes it from other solid tumors detected mainly in mature people. The early detection of cutaneous malignant melanoma (CMM) remains a priority and it is a key factor limiting mortality. Doctors and scientists around the world want to improve the quality of diagnosis and treatment, and are constantly looking for new, promising opportunities, including the use of microRNAs (miRNAs), to fight melanoma cancer. This article reviews miRNA as a potential biomarker and diagnostics tool as a therapeutic drugs in CMM treatment. We also present a review of the current clinical trials being carried out worldwide, in which miRNAs are a target for melanoma treatment.

Extracellular vesicles and melanoma: New perspectives on tumor microenvironment and metastasis

Secreted extracellular vesicles (EVs) are lipid bilayer particles without functional nucleus naturally released from cells which constitute an intercellular communication system. There is a broad spectrum of vesicles shed by cells based on their physical properties such as size (small EVs and large EVs), biogenesis, cargo and functions, which provide an increasingly heterogenous landscape. In addition, they are involved in multiple physiological and pathological processes. In cancer, EV release is opted by tumor cells as a beneficial process for tumor progression. Cutaneous melanoma is a cancer that originates from the melanocyte lineage and shows a favorable prognosis at early stages. However, when melanoma cells acquire invasive capacity, it constitutes the most aggressive and deadly skin cancer. In this context, extracellular vesicles have been shown their relevance in facilitating melanoma progression through the modulation of the microenvironment and metastatic spreading. In agreement with the melanosome secretory capacity of melanocytes, melanoma cells display an enhanced EV shedding activity that has contributed to the utility of melanoma models for unravelling EV cargo and functions within a cancer scenario. In this review, we provide an in-depth overview of the characteristics of melanoma-derived EVs and their role in melanoma progression highlighting key advances and remaining open questions in the field.

The Autocrine Role of Placental Extracellular Vesicles from Missed Miscarriage in Causing Senescence: Possible Pathogenesis of Missed Miscarriage

Placental dysfunction, including senescent changes, is associated with the pathogenesis of missed miscarriage, although the underlying mechanism is unclear. Increasing evidence indicates that placenta-specific miRNAs are packaged in extracellular vesicles (EVs) from placental syncytiotrophoblasts and are released into the maternal circulation. Aberrant cargos including miRNAs in placental EVs have been reported to be associated with the pathogenesis of complicated pregnancies. In this study, we compared the miRNA profiles in EVs derived from missed miscarriage and healthy placentae and investigated possible biological pathways which may be involved in senescence, one cause of missed miscarriage. The total concentration of RNA in placental EVs was not different between the two groups. However, there were 54 and 94 differentially expressed miRNAs in placental large and small EVs from missed miscarriage compared to EVs from healthy controls. The aberrantly expressed miRNAs seen in placental EVs were also observed in missed miscarriage placentae. Gene enrichment analysis showed that some of those differentially expressed miRNAs are involved in cellular senescence, endocytosis, cell cycle and endocrine resistance. Furthermore, transfection of trophoblasts by a single senescence-associated miRNA that was differentially expressed in placental EVs derived from missed miscarriage did not cause trophoblast dysfunction. In contrast, EVs derived from missed miscarriage placenta induced senescent changes in the healthy placenta. Our data suggested that a complex of placental EVs, rather than a few differentially expressed miRNAs in placental EVs derived from missed miscarriage placentae could contribute in an autocrine manner to placental senescence, one of the causes of missed miscarriage.

Identification of senescence-associated long non-coding RNAs to predict prognosis and immune microenvironment in patients with hepatocellular carcinoma

Background: Cellular senescence plays a complicated and vital role in cancer development because of its divergent effects on tumorigenicity. However, the long non-coding RNAs (lncRNAs) associated with tumor senescence and their prognostic value in hepatocellular carcinoma (HCC) remain unexplored. Methods: The trans-cancer oncogene-induced senescence (OIS) signature was determined by gene set variation analysis (GSVA) in the cancer genome atlas (TCGA) dataset. The OIS-related lncRNAs were identified by correlation analyses. Cox regression analyses were used to screen lncRNAs associated with prognosis, and an optimal predictive model was created by regression analysis of the least absolute shrinkage and selection operator (LASSO). The performance of the model was evaluated by Kaplan-Meier survival analyses, nomograms, stratified survival analyses, and receiver operating characteristic curve (ROC) analyses. Gene set enrichment analysis (GSEA) and cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) were carried out to explore the functional relevance and immune cell infiltration, respectively. Results: Firstly, we examined the pan-cancer OIS signature, and found several types of cancer with OIS strongly associated with the survival of patients, including HCC. Subsequently, based on the OIS signature, we identified 76 OIS-related lncRNAs with prognostic values in HCC. We then established an optimal prognostic model based on 11 (including NRAV, AC015908.3, MIR100HG, AL365203.2, AC009005.1, SNHG3, LINC01138, AC090192.2, AC008622.2, AL139423.1, and AC026356.1) of these lncRNAs by LASSO-Cox regression analysis. It was then confirmed that the risk score was an independent and potential risk indicator for overall survival (OS) (HR [95% CI] = 4.90 [2.74-8.70], p < 0.001), which outperforms those traditional clinicopathological factors. Furthermore, patients with higher risk scores also showed more advanced levels of a proinflammatory senescence-associated secretory phenotype (SASP), higher infiltration of regulatory T (Treg) cells and lower infiltration of naïve B cells, suggesting the regulatory effects of OIS on immune microenvironment. Additionally, we identified NRAV as a representative OIS-related lncRNA, which is over-expressed in HCC tumors mainly driven by DNA hypomethylation. Conclusion: Based on 11 OIS-related lncRNAs, we established a promising prognostic predictor for HCC patients, and highlighted the potential immune microenvironment-modulatory roles of OIS in HCC, providing a broad molecular perspective of tumor senescence.

Non-coding RNAs in skin cancers:Biological roles and molecular mechanisms

Cutaneous malignancies, including basal cell carcinoma, cutaneous squamous cell carcinoma, and cutaneous melanoma, are common human tumors. The incidence of cutaneous malignancies is increasing worldwide, and the leading cause of death is malignant invasion and metastasis. The molecular biology of oncogenes has drawn researchers’ attention because of the potential for targeted therapies. Noncoding RNAs, including microRNAs, long noncoding RNAs, and circular RNAs, have been studied extensively in recent years. This review summarizes the aspects of noncoding RNAs related to the metastasis mechanism of skin malignancies. Continuous research may facilitate the identification of new therapeutic targets and help elucidate the mechanism of tumor metastasis, thus providing new opportunities to improve the survival rate of patients with skin malignancies.

Oxidative-Stress-Sensitive microRNAs in UV-Promoted Development of Melanoma

Simple Summary

Exposure to ultraviolet (UV) rays from the sun is one of the most important modifiable risk factors for skin cancer. Melanoma is the most life-threatening type of skin cancer. UV-induced DNA damage and oxidative stress represent two main mechanisms that, directly and indirectly, contribute to melanomagenesis. In addition, an interplay of abnormally expressed microRNAs (miRNAs) and redox imbalance is a hallmark in several cancers, including melanoma. UV radiation can be the central hub between these two cellular aberrations, as it is able to stimulate both. Here, to gain new mechanistic insights into melanomagenesis and identify new therapeutic targets for the prevention and treatment of melanoma, we report current evidence suggesting a complex interaction between UV-promoted deregulation of redox-sensitive miRNAs and known signal-transduction pathways underlying malignant transformation of melanocytes to melanoma.

Abstract

Melanoma is the most aggressive and life-threatening form of skin cancer. Key molecular events underlying the melanocytic transformation into malignant melanoma mainly involve gene mutations in which exposure to ultraviolet (UV) radiation plays a prominent role. However, several aspects of UV-induced melanomagenesis remain to be explored. Interestingly, redox-mediated signaling and perturbed microRNA (miRNA) profiles appear to be interconnected contributing factors able to act synergistically in melanoma initiation and progression. Since UV radiation can promote both redox imbalance and miRNA dysregulation, a harmful crosstalk between these two key cellular networks, with UV as central hub among them, is likely to occur in skin tissue. Therefore, decoding the complex circuits that orchestrate the interaction of UV exposure, oxidative stress, and dysregulated miRNA profiling can provide a deep understanding of the molecular basis of the melanomagenesis process. Furthermore, these mechanistic insights into the reciprocal regulation between these systems could have relevant implications for future therapeutic approaches aimed at counteracting UV-induced redox and miRNome imbalances for the prevention and treatment of malignant melanoma. In this review, we illustrate current information on the intricate connection between UV-induced dysregulation of redox-sensitive miRNAs and well-known signaling pathways involved in the malignant transformation of normal melanocytes to malignant melanoma.

Physiological TLR4 regulation in human fetal membranes as an explicative mechanism of a pathological preterm case

The integrity of human fetal membranes is crucial for harmonious fetal development throughout pregnancy. Their premature rupture is often the consequence of a physiological phenomenon that has been exacerbated. Beyond all the implied biological processes, inflammation is of primary importance and is qualified as ‘sterile’ at the end of pregnancy. In this study, complementary methylomic and transcriptomic strategies on amnion and choriodecidua explants obtained from the altered (cervix zone) and intact fetal membranes at term and before labour were used. By cross-analysing genome-wide studies strengthened by in vitro experiments, we deciphered how the expression of toll-like receptor 4 (TLR4), an actor in pathological fetal membrane rupture, is controlled. Indeed, it is differentially regulated in the altered zone and between both layers by a dual mechanism: (1) the methylation of TLR4 and miRNA promoters and (2) targeting by miRNA (let-7a-2 and miR-125b-1) acting on the 3’-UTR of TLR4. Consequently, this study demonstrates that fine regulation of TLR4 is required for sterile inflammation establishment at the end of pregnancy and that it may be dysregulated in the pathological premature rupture of membranes.

Revisiting miRNA Association with Melanoma Recurrence and Metastasis from a Machine Learning Point of View

The diagnostic and prognostic value of miRNAs in cutaneous melanoma (CM) has been broadly studied and supported by advanced bioinformatics tools. From early studies using miRNA arrays with several limitations, to the recent NGS-derived miRNA expression profiles, an accurate diagnostic panel of a comprehensive pre-specified set of miRNAs that could aid timely identification of specific cancer stages is still elusive, mainly because of the heterogeneity of the approaches and the samples. Herein, we summarize the existing studies that report several miRNAs as important diagnostic and prognostic biomarkers in CM. Using publicly available NGS data, we analyzed the correlation of specific miRNA expression profiles with the expression signatures of known gene targets. Combining network analytics with machine learning, we developed specific non-linear classification models that could successfully predict CM recurrence and metastasis, based on two newly identified miRNA signatures. Subsequent unbiased analyses and independent test sets (i.e., a dataset not used for training, as a validation cohort) using our prediction models resulted in 73.85% and 82.09% accuracy in predicting CM recurrence and metastasis, respectively. Overall, our approach combines detailed analysis of miRNA profiles with heuristic optimization and machine learning, which facilitates dimensionality reduction and optimization of the prediction models. Our approach provides an improved prediction strategy that could serve as an auxiliary tool towards precision treatment.

Non-coding RNA dysregulation in skin cancers

Skin cancers are the most common cancers worldwide. They can be classified in melanoma and non-melanoma skin cancer (NMSC), the latter includes squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and merkel cell carcinoma (MCC). In recent years, the crucial role of non-coding RNAs (ncRNAs) in skin cancer pathogenesis has become increasingly evident. NcRNAs are functional RNA molecules that lack any protein-coding activity. These ncRNAs are classified based on their length: small, medium-size, and long ncRNAs. Among the most studied ncRNAs there are microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNA (circRNAs). ncRNAs have the ability to regulate gene expression at transcriptional and post-transcriptional levels and are involved in skin cancer cell proliferation, angiogenesis, invasion, and metastasis. Many ncRNAs exhibit tissue- or cell-specific expression while others have been correlated to tumor staging, drug resistance, and prognosis. For these reasons, ncRNAs have both a diagnostic and prognostic significance in skin cancers. Our review summarizes the functional role of ncRNAs in skin cancers and their potential clinical application as biomarkers.

Molecular Mechanisms of PD-1 and PD-L1 Activity on a Pan-Cancer Basis: A Bioinformatic Exploratory Study

Immune checkpoint blockade targeting PD-1 (PDCD1)/PD-L1 (CD274) is increasingly used for multiple cancers. However, efficacy and adverse-related events vary significantly. This bioinformatic study interrogated molecular differences pertaining to PDCD1/CD274 and their correlated genes on a pan-cancer basis to identify differences between cancer types. Patient RNA-seq data from fifteen cancer types were accessed on cBioPortal to determine the role of PDCD1/CD274 in patient survival and to identify positively and negatively correlated genes, which were also assessed for clinical relevance. Genes correlating with PDCD1/CD274 across multiple cancers were taken forward for drug repurposing via DRUGSURV and microRNA analysis using miRDB and miRabel. MicroRNAs were also screened for clinical relevance using OncomiR. Forty genes were consistently correlated with PDCD1/CD274 across multiple cancers, with the cancers themselves exhibiting a differential role for the correlated genes in terms of patient survival. Esophageal and renal cancers in particular stood out in this regard as having a unique survival profile. Forty-nine putative microRNAs were identified as being linked to the PDCD1/CD274 network, which were taken forward and further assessed for clinical relevance using OncomiR and previously published literature. One hundred and thirty significant survival associations for 46 microRNAs across fourteen groups of cancers were identified. Finally, a total of 23 putative repurposed drugs targeting multiple components of the PDCD1/CD274 network were identified, which may represent immunotherapeutic adjuvants. Taken together, these results shed light on the varying PDCD1/CD274 networks between individual cancers and signpost a need for more cancer-specific investigations and treatments.

Deregulation of the cell cycle and related microRNA expression induced by vinyl chloride monomer in the hepatocytes of rats

Vinyl chloride (VC) is a confirmed human carcinogen associated with hepatocellular carcinoma and angiosarcoma. However, the role of microRNAs (miRNAs) in liver cell cycle changes under VC exposure remains unclear, which prevents research on the mechanism of VC-induced carcinogenesis. In this study, male rats were injected intraperitoneally with VC (0, 5, 25, and 125 mg/kg body weight) for 6, 8, and 12 weeks. Cell cycle analysis of liver cells, miRNA-222, miRNA-199a, miRNA-195, and miRNA-125b expression in the liver and serum, and target protein expression were performed at different time points. The results showed a higher percentage of hepatocytes in the G1/G0 and S phases at the end of 6 and 12 weeks of VC exposure, respectively. MiRNA-222 expression decreased initially and then increased, whereas miRNA-199a, miRNA-195, and miRNA-125b expression increased initially and then decreased, which corresponded with changes in cell cycle distribution and related target proteins expression (p27, cyclinA, cyclinD1, and CDK6). The corresponding expression levels of miRNAs in serum did not change. Dynamic changes in miR-222, miR-199a, miR-195, and miR-125b induced by VC can lead to cell cycle deregulation by affecting cell cycle-related proteins, and these miRNAs can serve as early biomarkers for malignant transformation caused by VC.

Circular RNA 0086996 regulates growth and migration of osteosarcoma cells via miR-125b-5p

Circular RNAs (CircRNAs) have been found to be critical in tumorigenesis; however, the role of CircRNAs in osteosarcoma is to be further studied. In this study, we preliminarily identified the up-expressed CircRNAs and its downstream microRNA in osteosarcoma and investigated its potential regulation mechanism. Hsa_circ_0086996 (Circ_0086996) was found to upregulated in tumor tissue compared to adjacent tissue. Circ_0086996 was significantly overexpressed in osteosarcoma tissue, as well as in osteosarcoma cell lines of SAOS2 and MG-63. Circ_0086996 knockdown significantly suppressed cell proliferation, migration, and invasion. Circ_0086996 knockdown also induced cell cycle arrest in G0/G1 phaseand promoted cell apoptosis in SAOS2 and MG-63 cells. Bioinformatics analysis revealed that miR-125b-5p might be of complementary binding region with Circ_0086996, which was confirmed by dual-luciferase reporter assay. Moreover, Circ_0086996 could reverse the effect of miR-125b-5p, as knockdown of Circ_0086996 or application of miR-125b-5p both can inhibit cell proliferation, migration, invasion and promote cell apoptosis and cell cycle arrest. Our study discovers that Circ_0086996 acts as miR-125b-5p sponge to mediate the tumorigenicity, which could act as a potential biomarker for the osteosarcoma and provides a novel insight for the mechanism in osteosarcoma.

Advances in Natural or Synthetic Nanoparticles for Metastatic Melanoma Therapy and Diagnosis

Advanced melanoma is still a major challenge in oncology. In the early stages, melanoma can be treated successfully with surgery and the survival rate is high, nevertheless the survival rate drops drastically after metastasis dissemination. The identification of parameters predictive of the prognosis to support clinical decisions and of new efficacious therapies are important to ensure patients the best possible prognosis. Recent progress in nanotechnology allowed the development of nanoparticles able to protect drugs from degradation and to deliver the drug to the tumor. Modification of the nanoparticle surface by specific molecules improves retention and accumulation in the target tissue. In this review, we describe the potential role of nanoparticles in advanced melanoma treatment and discuss the current efforts of designing polymeric nanoparticles for controlled drug release at the site upon injection. In addition, we highlight the advances as well as the challenges of exosome-based nanocarriers as drug vehicles. We place special focus on the advantages of these natural nanocarriers in delivering various cargoes in advanced melanoma treatment. We also describe the current advances in knowledge of melanoma-related exosomes, including their biogenesis, molecular contents and biological functions, focusing our attention on their utilization for early diagnosis and prognosis in melanoma disease.

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

The formation of the skeleton occurs throughout the lives of vertebrates and is achieved through the balanced activities of two kinds of specialized bone cells: the bone-forming osteoblasts and the bone-resorbing osteoclasts. Impairment in the remodeling processes dramatically hampers the proper healing of fractures and can also result in malignant bone diseases such as osteosarcoma. MicroRNAs (miRNAs) are a class of small non-coding single-strand RNAs implicated in the control of various cellular activities such as proliferation, differentiation, and apoptosis. Their post-transcriptional regulatory role confers on them inhibitory functions toward specific target mRNAs. As miRNAs are involved in the differentiation program of precursor cells, it is now well established that this class of molecules also influences bone formation by affecting osteoblastic differentiation and the fate of osteoblasts. In response to various cell signals, the tumor-suppressor protein p53 activates a huge range of genes, whose miRNAs promote genomic-integrity maintenance, cell-cycle arrest, cell senescence, and apoptosis. Here, we review the role of three p53-related miRNAs, miR-34c, -125b, and -203, in the bone-remodeling context and, in particular, in osteoblastic differentiation. The second aim of this study is to deal with the potential implication of these miRNAs in osteosarcoma development and progression.

MicroRNA Ratios Distinguish Melanomas from Nevi

The use of microRNAs as biomarkers has been proposed for many diseases, including the diagnosis of melanoma. Although hundreds of microRNAs have been identified as differentially expressed in melanomas as compared to benign melanocytic lesions, a limited consensus has been achieved across studies, constraining the effective use of these potentially useful markers. In this study, we applied a machine learning-based pipeline to a dataset consisting of genetic features, clinical features, and next-generation microRNA sequencing from micro-dissected formalin-fixed paraffin embedded melanomas and their adjacent benign precursor nevi. We identified patient age and tumor cellularity as variables that frequently confound the measured expression of potentially diagnostic microRNAs. By employing the ratios of microRNAs that were either enriched or depleted in melanoma compared to the nevi as a normalization strategy, we developed a model that classified all the available published cohorts with an area under the receiver operating characteristic curve of 0.98. External validation on an independent cohort classified lesions with 81% sensitivity and 88% specificity and was uninfluenced by the tumor content of the sample or patient age.

Circulating microRNAs as biomarkers for early diagnosis of cutaneous melanoma

Introduction: Cutaneous melanoma is the deadliest form of skin cancer, with a dramatic increase in the incidence rate worldwide over the past decade. Early detection has been shown to improve the outcome of melanoma patients. The identification of noninvasive biomarkers able to identify melanoma at an early stage remains an unmet clinical need. Circulating miRNAs (c-miRNAs), small non-coding RNAs, appear as potential ideal candidate biomarkers due to their stability in biological fluids and easy detectability. Moreover, c-miRNAs are reported to be heavily deregulated in cancer patients.Areas covered: This review examines evidence of the specific c-miRNAs or panels of c-miRNAs reported to be useful in discriminating melanoma from benign cutaneous lesions.Expert opinion: Although the interesting reported by published studies, the non-homogeneity of detection and normalization methods prevents the individuation of single c-miRNA or panel of c-miRNAs that are specific for early detection of cutaneous melanoma. In the future, prospective wide and well-designed clinical trials will be needed to validate the diagnostic potential of some of the c-miRNA candidates in clinical practice.

MicroRNA Networks Modulate Oxidative Stress in Cancer

Imbalanced regulation of reactive oxygen species (ROS) and antioxidant factors in cells is known as "oxidative stress (OS)". OS regulates key cellular physiological responses through signal transduction, transcription factors and noncoding RNAs (ncRNAs). Increasing evidence indicates that continued OS can cause chronic inflammation, which in turn contributes to cardiovascular and neurological diseases and cancer development. MicroRNAs (miRNAs) are small ncRNAs that produce functional 18-25-nucleotide RNA molecules that play critical roles in the regulation of target gene expression by binding to complementary regions of the mRNA and regulating mRNA degradation or inhibiting translation. Furthermore, miRNAs function as either tumor suppressors or oncogenes in cancer. Dysregulated miRNAs reportedly modulate cancer hallmarks such as metastasis, angiogenesis, apoptosis and tumor growth. Notably, miRNAs are involved in ROS production or ROS-mediated function. Accordingly, investigating the interaction between ROS and miRNAs has become an important endeavor that is expected to aid in the development of effective treatment/prevention strategies for cancer. This review provides a summary of the essential properties and functional roles of known miRNAs associated with OS in cancers.

MicroRNA-125 in immunity and cancer

MicroRNAs (miRNAs) are small non-coding RNAs that play a wide variety of critical roles in different biological processes by post-transcriptionally regulating gene expression. They access diverse regulatory pathways during various stages of cellular differentiation, growth, and apoptosis, and can contribute to both normal and diseased functions. One important family of miRNAs involved in these functions is the miR-125 family (miR-125a and miR-125b). Investigations have been made to increasingly uncover the mechanisms by which the miR-125 family regulates normal homeostasis and growth in a variety of cell types including immune cells, and how dysregulation of miR-125a and miR-125b can lead to disease pathogenesis and tumorigenesis. In this review, we summarize what is currently known about miR-125a and miR-125b, mainly focusing on their roles in immune cell development and function as well as tumor suppression and promotion.

miR-125b Upregulates miR-34a and Sequentially Activates Stress Adaption and Cell Death Mechanisms in Multiple Myeloma

miR-125b, ubiquitously expressed and frequently dysregulated in several tumors, has gained special interest in the field of cancer research, displaying either oncogenic or oncosuppressor potential based on tumor type. We have previously demonstrated its tumor-suppressive role in multiple myeloma (MM), but the analysis of molecular mechanisms needs additional investigation. The purpose of this study was to explore the effects of miR-125b and its chemically modified analogs in modulating cell viability and cancer-associated molecular pathways, also focusing on the functional aspects of stress adaptation (autophagy and senescence), as well as programmed cell death (apoptosis). Based on the well-known low microRNA (miRNA) stability in therapeutic application, we designed chemically modified miR-125b mimics, laying the bases for their subsequent investigation in in vivo models. Our study clearly confirmed an oncosuppressive function depending on the repression of multiple targets, and it allowed the identification, for the first time, of miR-125b-dependent miR-34a stimulation as a possible consequence of the inhibitory role on the interleukin-6 receptor (IL-6R)/signal transducer and activator of transcription 3 (STAT3)/miR-34a feedback loop. Moreover, we identified a pattern of miR-125b-co-regulated miRNAs, shedding light on possible new players of anti-MM activity. Finally, functional studies also revealed a sequential activation of senescence, autophagy, and apoptosis, thus indicating, for the first two processes, an early cytoprotective and inhibitory role from apoptosis activation.

Interplay between small and long non-coding RNAs in cutaneous melanoma: a complex jigsaw puzzle with missing pieces

The incidence of cutaneous melanoma (CM) has increased in the past few decades. The biology of melanoma is characterized by a complex interaction between genetic, environmental and phenotypic factors. A greater understanding of the molecular mechanisms that promote melanoma cell growth and dissemination is crucial to improve diagnosis, prognostication, and treatment of CM. Both small and long non-coding RNAs (lncRNAs) have been identified to play a role in melanoma biology; microRNA and lncRNA expression is altered in transformed melanocytes and this in turn has functional effects on cell proliferation, apoptosis, invasion, metastasis, and immune response. Moreover, specific dysregulated ncRNAs were shown to have a diagnostic or prognostic role in melanoma and to drive the establishment of drug resistance. Here, we review the current literature on small and lncRNAs with a role in melanoma, with the aim of putting into some order this complex jigsaw puzzle.

Downregulation of intratumoral expression of miR-205, miR-200c and miR-125b in primary human cutaneous melanomas predicts shorter survival

While only 15–25 percent of melanoma patients develop distant metastasis and die, this disease is still responsible for the majority of skin cancer-related deaths. The availability of adjuvant therapies makes the selection of high-risk patients essential. We evaluated the intratumoral expression of ten miRNAs in primary melanomas in relation to its ability to predict melanoma survival. To this end, we correlated miRNA expression in 132 cryopreserved primary and metastatic tumors with clinicopathological factors and clinical outcome. We found sequential downregulation of intratumoral expression of miR-125b, miR-182, miR-200c and miR-205 over the full spectrum of melanoma progression. Moreover, downregulation of these miRNAs occurred in primary melanomas that further disseminated to distant sites. Furthermore, miR-125b, miR-200c and miR-205 correlated as independent factors with shorter survival. Our in vitro findings demonstrate that loss of miR-205 potentiates the invasive ability of melanoma cells. We conclude that the downregulation of miR-205 in primary melanomas is an intrinsic property that might contribute to distant metastasis. In particular, the interaction of melanoma cells with the extracellular matrix is one of the key mechanisms by which miR-205 influences melanoma metastasis. In conclusion, miR-125b, miR-200c and miR-205 are useful prognostic biomarkers at the time of diagnosis to select high-risk patients.

MicroRNA (miR) 125b regulates cell growth and invasion in pediatric low grade glioma

Members of the miR-125 family are strongly expressed in several tissues, particularly brain, but may be dysregulated in cancer including adult and pediatric glioma. In this study, miR-125 members were downregulated in pilocytic astrocytoma (PA) as a group compared to non-neoplastic brain in the Agilent platform. In the Nanostring platform, miR-125 members were downregulated primarily in pleomorphic xanthoastrocytomas and gangliogliomas. Using CISH for miR-125b, highest levels of expression were present in grade II tumors (11/33, 33% grade II tumors with 3+ expression compared to 3/70, 4% grade I tumors) (p < 0.001). When focusing on the two histologic subgroups with the largest number of samples, PA and diffuse astrocytoma (DA), the highest expression levels were present in DA, in comparison with the PA group (p = 0.01). Overexpression of miR-125b in pediatric low grade glioma (PLGG) derived cell lines (Res186, Res259, and BT66) resulted in decreased growth and invasion, as well as apoptosis. Additionally, miR-125b overexpression in BT66 resulted in senescence. These findings suggest that miR-125 is frequently underexpressed in PLGG, and overexpression results in a decrease in cell growth and induction of apoptosis, findings that deserve further investigation given its potential as a novel therapeutic strategy for PLGG.

Long noncoding RNA LINC00152 promotes cell proliferation through competitively binding endogenous miR-125b with MCL-1 by regulating mitochondrial apoptosis pathways in ovarian cancer

Recently, an increasing number of studies have focused on the key function of long noncoding RNAs (lncRNAs) in biological activity. Abnormal lncRNA expression was found to relate to the development and pathogenesis of multiple cancers. LncRNA LINC00152 served as an oncogene in multiple cancers; however, its role in ovarian cancer remains unknown. In our research study, LINC00152 was upregulated in ovarian cancer tissues and cell lines. An increasing LINC00152 level was positively correlated with the histological grade, clinical stage, and poor prognosis of ovarian cancer patients. In addition, knockdown of LINC00152 reduced cell growth, induced cell apoptosis, and suppressed tumor growth. Moreover, we revealed that LINC00152 and Myeloid cell leukemia‐1 (MCL‐1) were targeted by miR‐125b and had the same miR‐125b combining site. The miR‐125b level was negatively correlated with the expression of LINC00152, while MCL‐1 was positively related to the LINC00152 level. MiR‐125b could affect LINC00152 levels as evaluated by qRT‐PCR. Finally, we affirmed that LINC00152 mediated cell proliferation by affecting MCL‐1 expression and MCL‐1‐mediated mitochondrial apoptosis pathways and by working as a competitive endogenous RNA (ceRNA) of miR‐125b. In summary, based on ceRNA theory, the combined research on miR‐125b and MCL‐1, and taking LINC00152 as a new study point, we provide new insight into the molecular mechanism of reversing cell proliferation in ovarian cancer.

Quantification of microRNA-21 and microRNA-125b in melanoma tissue

Although microRNAs (miRNAs) have emerged as potent mediators of melanoma development and progression, a precise understanding of their oncogenic role remains unclear. In this study, we analysed formalin-fixed and paraffin-embedded tissues from two separate melanoma cohorts and from a series of benign melanocytic nevi. Using three different quantification methods [array analysis, quantitative PCR (qPCR) and in-situ hybridization (ISH) quantified by digital image analysis], we found considerable miRNA dysregulation in tumours. Using array analysis, samples mainly clustered according to their biological group (benign vs. malignant) and 77 miRNAs differed significantly between nevi and melanoma samples. Increase of miR-21 and miR-142, and decrease of miR-125b, miR-211, miR-101 and miR-513c in the melanomas were verified in both cohorts using qPCR, whereas the decrease of miR-205 observed with array analysis could not be confirmed using qPCR. ISH with digital quantification showed expression of miR-21 and miR-125b in the melanocytic lesions. miR-21 ISH was increased in melanomas, whereas quantification of miR-125b showed uniform ISH expression across nevi and melanomas. Our results support the important involvement of different miRNAs in melanoma biology and may serve as solid basics for further miRNA investigations in melanoma formalin-fixed and paraffin-embedded tissue. In particular, there is increased expression of miR-21 in melanomas compared with benign nevi.

Human Aging and Cancer: Role of miRNA in Tumor Microenvironment

Human aging is an inevitable and complex phenomenon characterized by a progressive, gradual degradation of physiological and cellular processes that leads from vulnerability to death. Mammalian somatic cells display limited proliferative properties in vitro that results in a process of permanent cell cycle arrest commonly known as senescence. Events leading to cellular senescence are complex but may be due to the increase in tumor suppressor genes, caused by lifetime somatic mutations. Cumulative mutation leaves an imprint on the genome of the cell, an important risk factor for the occurrence of cancer. Adults over the age of 65+ are vulnerable to age related diseases such as cancers but such changes may begin at middle age. MicroRNAs (miRNAs), which are small non-coding RNA, can regulate cancer progression, recurrence and metastasis. This chapter discusses the role of miRNA in tumor microenvironment, consequent to aging.

Recent advances in melanoma research via "omics" platforms

Melanoma has a high mortality rate and metastatic melanoma is highly resistant to conventional therapies. "Omics" fields such as proteomics and microRNA and exosome studies have provided new knowledge to complement the information generated by genomic studies. This work aimed to review the current status of biomarker discovery for melanoma through multi-"omics" platforms. A few sets of novel microRNAs and proteins are described, some of them with important implications in suppressing melanoma at different stages. Upregulation of genes involved in angiogenesis, immunosuppressive factors, modification of stroma, capture of melanoma cells in lymph nodes and factors responsible for tumour cell recruitment have been identified in exosomes, among molecules with other functions. A remarkable series of proteins involved in epithelial-mesenchymal/mesenchymal-epithelial transitions, inflammation, motility, proliferation and progression processes, centrosome amplification, aneuploidy, inhibition of CD8+ effector T-cells, and metastasis in general were identified. Genomic and protein-protein interactions or metabolome levels were not analysed. Proteomics tools such as Orbitrap shotgun mass spectrometry or deep mining proteomic analysis utilizing high-resolution reversed phase nanoseparation in combination with mass spectrometry are also discussed. The application of these tools together with bioinformatics approaches applied to the clinical setting will enable the implementation of personalized medicine in the near future.

MiR-216b inhibits cell proliferation by targeting FOXM1 in cervical cancer cells and is associated with better prognosis

Background

Our previous study showed FOXM1 expression was significantly up-regulated in cervical cancer, and was associated with poor prognosis. To clarify miRNAs-FOXM1 modulation pathways, in this study, we investigated the relationships between miR-216b and FOXM1 and the role of miR-216b in cell proliferation and prognosis of cervical cancer patients.

Methods

Western blotting and qPCR were used to determine expression of FOXM1, cell cycle related factors and miR-216b level. MiR-216b overexpression and inhibited cell models were constructed, and siRNA was used for FOXM1 silencing. Cell proliferation was analyzed by MTT and colony formation assay. Dual luciferase reporter assay system was used to clarify the relationships between miR-216b and FOXM1. Kaplan-Meier survival analysis was used to evaluate prognosis.

Results

MiR-216b was down-regulated in cervical cancer cells and tissues, and its ectopic expression could decrease cell proliferation. Western blotting analysis showed miR-216b can inhibit cell proliferation by regulating FOXM1-related cell cycle factors, suppressing cyclinD1, c-myc, LEF1 and p-Rb and enhancing p21 expression. Repressing of miR-216b stimulated cervical cancer cell proliferation, whereas silencing FOXM1 expression could reverse this effect. Western blotting and luciferase assay results proved FOXM1 is a direct target of miR-216b. Survival analysis showed higher level of miR-216b was associated with better prognosis in cervical cancer patients.

Conclusions

FOXM1 expression could be suppressed by miR-216b via direct binding to FOXM1 3′-UTR and miR-216b could inhibit cell proliferation by regulating FOXM1 related Wnt/β-catenin signal pathway. MiR-216b level is related to prognosis in cervical cancer patients and may serve as a potential prognostic marker.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3650-5) contains supplementary material, which is available to authorized users.

FAK regulates E-cadherin expression via p-SrcY416/p-ERK1/2/p-Stat3Y705 and PPARγ/miR-125b/Stat3 signaling pathway in B16F10 melanoma cells

Focal adhesion kinase (FAK) is involved in tumor cell migration and metastasis. However, the underlying mechanism remains unclear. Here, we present a signaling pathway involved in the regulation of melanoma cell migration by FAK. We found that the interference of FAK expression suppressed B16F10 cell migration/metastasis, and altered the expressions of genes involved in melanoma migration/metastasis. The down-regulation of FAK inhibited the expression of p-Src^Y416, p-ERK_1/2, Stat3 and p-Stat3^Y705, while promoted the expression of PPARγ, miR-125b and E-cadherin. Then we found that FAK inhibited E-cadherin expression via p-Src^Y416/p-ERK_1/2/ p-Stat3^Y705 and PPARγ/miR-125b/Stat3 signaling pathway in B16F10 cell. Moreover, miR-125b inhibited B16F10 cell migration. Furthermore, we repeated the key data with human melanoma cell line A375. The results obtained from A375 cells fell in line with those from B16F10 cells. Using Oncomine database, we found that the mRNA levels of FAK, Src, ERK_1/2 and Stat3 increased, while the mRNA levels of PPARγ, C21orf34 (miR-125b host gene) and E-cadherin decreased in human metastatic melanoma. The data from human breast cancer confirmed those from metastatic melanoma.

Taken together, our study suggests that down-regulation of FAK promotes E-cadherin expression via p-Src^Y416/p-ERK_1/2/p-Stat3^Y705 and PPARγ/miR-125b/Stat3 signaling pathway. Our findings provide a novel explanation regarding how FAK promotes melanoma cell migration, suggesting that FAK might be a potential target for melanoma therapy.

cel-mir-237 and its homologue, hsa-miR-125b, modulate the cellular response to ionizing radiation

Elucidating the mechanisms involved in sensitizing radioresistant tumors to ionizing radiation (IR) treatments while minimizing injury to surrounding normal tissue is an important clinical goal. Due to their sequence-derived specificity and properties as gene regulators in IR-affected pathways, microRNAs (miRNAs) could serve as adjuvant therapeutic agents that alter cellular sensitivity to radiation treatment. To identify radiosensitizing miRNAs, we initially utilized the Caenorhabditis elegans vulval cell model, an in vivo system developed to study IR-dependent radiosensitivity as a measure of clonogenic cell death. We tested several candidate miRNA-deletion mutants post γ-irradiation and identified cel-mir-237 as a miRNA which when deleted caused animals to be more resistant to IR, whereas cel-mir-237 overexpressing strains were IR sensitive. In addition, wild-type animals downregulated cel-mir-237 levels post IR in a time-dependent manner. We identified jun-1 (JUN transcription factor homolog) as a novel target of cel-mir-237. Specifically, jun-1 transcript levels increased in wild-type animals post γ-irradiation, and loss of cel-mir-237 also resulted in higher jun-1 expression. As expected, loss of jun-1 resulted in IR sensitivity, similar to the phenotype of cel-mir-237 overexpressors. As miR-237 is the homolog of human miR-125, we validated our findings in MCF-7 and MDA-MB-231 breast cancer cell lines, which harbor lower hsa-miR-125b levels than normal human mammary epithelial cells (HMECs). Forced expression of hsa-miR-125b in these cells resulted in radiosensitivity, as seen by reduced clonogenic survival, enhanced apoptotic activity and enhanced senescence post IR. Finally, re-expression of c-JUN in MDA-MB-231 cells promoted radioresistance and abrogated miR-125-mediated radiosensitization. Our findings suggest that overexpression of cel-mir-237 and its homolog, hsa-miR-125b, functions as sensitizers to γ-irradiation in both a nematode in vivo model and breast cancer cells, and could potentially be utilized as an adjuvant therapeutic to enhance radiation sensitivity.

Radotinib inhibits acute myeloid leukemia cell proliferation via induction of mitochondrial-dependent apoptosis and CDK inhibitors

Radotinib is a BCR-ABL1 tyrosine kinase inhibitor approved for the second-line treatment of chronic myeloid leukemia. However, effects of radotinib on acute myeloid leukemia (AML) are unclear. In the present study, we observed that radotinib exerted cytotoxic effects on AML cells. Of the various AML cell lines examined (NB4, HL60, HEL 92.1.7, and THP-1), Kasumi-1 was the most sensitive to radotinib. Results of microarray analysis showed that 417 and 595 genes associated with apoptosis and cell cycle regulation, respectively, were differently expressed (i.e., showed >2-fold difference in expression). Radotinib-induced apoptosis involved the mitochondrial pathway. Moreover, radotinib increased the apoptosis of and induced caspase-3 activity in both Kasumi-1 cells and bone marrow cells (BMCs) obtained from patients with AML. Radotinib also increased cleaved caspase-3, caspase-7, and caspase-9 levels and decreased the number of proliferating Kasumi-1 cells and BMCs from patients with AML. In addition, radotinib induced G0/G1 phase arrest by inducing CDKIs p21 and p27 and by inhibiting CDK2, CDK4, and CDK6. These results indicate that radotinib induces caspase-dependent apoptosis and G0/G1 phase arrest in AML cells by regulating CDKI-CDK-cyclin cascade. Moreover, these results indicate that radotinib inhibits AML cell proliferation by inducing mitochondria-dependent apoptosis and CDKIs p21 and p27. To our knowledge, this is the first study to show that radotinib can be potentially used for the anti-leukemic therapy of patients with AML.

Association between different risk factors and vascular accelerated ageing (EVA study): study protocol for a cross-sectional, descriptive observational study

INTRODUCTION

The process of population ageing that is occurring in developed societies represents a major challenge for the health system. The aim of this study is to analyse factors that have an influence on early vascular ageing (EVA), estimated by carotid-femoral pulse wave velocity (cf-PWV) and Cardio Ankle Vascular Index (CAVI), and to determine differences by gender in a Spanish population.

METHODS AND ANALYSIS

An observational, descriptive, cross-sectional study.

STUDY POPULATION

From the population assigned to the participating healthcare centres, a cluster random sampling stratified by age and gender will be performed to obtain 500 participants aged between 35 and 75. Those who meet the inclusion criteria and give written informed consent will be included in the study.

MEASUREMENTS

Main dependent variables: cf-PWV determined using the SphygmoCor System and CAVI estimated using VASERA. Secondary dependent variables: telomere length, carotid intima-media thickness, central and peripheral augmentation index, ankle-brachial pulse wave velocity, ankle-brachial index, retinal arteriovenous index, and renal and cardiac organ damage.

INDEPENDENT VARIABLES

lifestyles (physical activity, adherence to the Mediterranean diet, alcohol and tobacco consumption); psychological factors (depression, anxiety and chronic stress); inflammatory factors and oxidative stress.

ETHICS AND DISSEMINATION

The study has been approved by the clinical research ethics committee of the healthcare area of Salamanca. All study participants will sign an informed consent form agreeing to participate in the study in compliance with the Declaration of Helsinki and the WHO standards for observational studies. The results of this study will allow the understanding of the relationship of the different influencing factors and their relative weight in the development of EVA. At least 5 publications in first-quartile scientific journals are planned.

TRIAL REGISTRATION NUMBER

NCT02623894; Pre-results.

Regulation of Melanoma Progression through the TCF4/miR-125b/NEDD9 Cascade

Melanoma progression from a primary lesion to a distant metastasis is a complex process associated with genetic alterations, epigenetic modifications, and phenotypic switches. Elucidation of these phenomena may indicate how to interfere with this fatal disease. The role of microRNAs as key negative regulators of gene expression, controlling all cellular processes including cell migration and invasion, is now being recognized. Here, we used in silico analysis of microRNA expression profiles of primary and metastatic melanomas and functional experiments to show that microRNA-125b (miR-125b) is a determinant candidate of melanoma progression: (i) miR-125b is more strongly expressed in aggressive metastatic than primary melanomas, (ii) there is an inverse correlation between the amount of miR-125b and overall patient survival, (iii) invasion/migration potentials in vitro are inversely correlated with the amount of miR-125b in a series of human melanoma cell lines, and (iv) inhibition of miR-125b reduces migratory and invasive potentials without affecting cell proliferation in vitro. Furthermore, we show that neural precursor cell expressed developmentally down-regulated protein 9 (i.e., NEDD9) is a direct target of miR-125b and is involved in modulating melanoma cell migration and invasion. Also, transcription factor 4, associated with epithelial-mesenchymal transition and invasion, induces the transcription of miR-125b-1. In conclusion, the transcription factor 4/miR-125b/NEDD9 cascade promotes melanoma cell migration/invasion.

MicroRNA dysregulation in melanoma

Melanoma is the deadliest form of skin cancer. Current challenges facing the management of melanoma include accurate prediction of individuals who will respond to adjuvant therapies as well as early detection of recurrences. These and other challenges have prompted investigation into biomarkers that could be used as diagnostic, prognostic and therapeutic aids. MicroRNAs (miRs) are small 19-22 nucleotide RNA inhibitors of protein translation. Over 800 different miRs are present within cells and importantly miR expression profiles may vary across different cells types and stages of malignancy. Unique expression profiles have been described for malignant melanoma; however, this work has yet to be translated into routine clinical practice. We highlight pertinent studies involving common miRs implicated in the oncogenesis of melanoma including miR-21, miR-125b, miR-150, miR-155, miR-205, and miR-211. In particular, emphasis is placed upon differential expression across different stages of melanoma progression, prognostic implications and potential mechanistic involvement. Focused efforts on inhibition of these miRs could be the most efficient method of translating preclinical endeavors into clinically meaningful applications.

miRNA signature identification of retinoblastoma and the correlations between differentially expressed miRNAs during retinoblastoma progression

PURPOSE

Retinoblastoma (RB) is a common pediatric cancer. The study aimed to uncover the mechanisms of RB progression and identify novel therapeutic biomarkers.

METHODS

The miRNA expression profile GSE7072, which includes three RB samples and three healthy retina samples, was used. After data normalization using the preprocessCore package, differentially expressed miRNAs (DE-miRs) were selected by the limma package. The targets of the DE-miRs were predicted based on two databases, followed by construction of the miRNA-target network. Pathway enrichment analysis was conducted for the targets of the DE-miRNAs using DAVID. The CTD database was used to predict RB-related genes, followed by clustering analysis using the pvclust package. The correlation network of DE-miRs was established. MiRNA expression was validated in another data set, GSE41321.

RESULTS

In total, 24 DE-miRs were identified whose targets were correlated with the cell cycle pathway. Among them, hsa-miR-373, hsa-miR-125b, and hsa-miR-181a were highlighted in the miRNA-target regulatory network; 14 DE-miRs, including hsa-miR-373, hsa-miR-125b, hsa-miR-18a, hsa-miR-25, hsa-miR-20a, and hsa-let-7 (a, b, c), were shown to distinguish RB from healthy tissue. In addition, hsa-miR-25, hsa-miR-18a, and hsa-miR-20a shared the common target BCL2L11; hsa-let-7b and hsa-miR-125b targeted the genes CDC25A, CDK6, and LIN28A. Expression of three miRNAs in GSE41321 was consistent with that in GSE7072.

CONCLUSIONS

Several critical miRNAs were identified in RB progression. Hsa-miR-373 might regulate RB invasion and metastasis, hsa-miR-181a might involve in the CDKN1B-mediated cell cycle pathway, and hsa-miR-125b and hsa-let-7b might serve as tumor suppressors by coregulating CDK6, CDC25A, and LIN28A. The miRNAs hsa-miR-25, hsa-miR-18a, and hsa-miR-20a might exert their function by coregulating BCL2L1.

MicroRNA-125b suppresses the epithelial-mesenchymal transition and cell invasion by targeting ITGA9 in melanoma

Increasing evidence has shown that aberrant miRNAs contribute to the development and progression of human melanoma. Previous studies have shown that miR-125b functions as a suppressor in malignant melanoma. However, the molecular function and mechanism by which miR-125b influences melanoma growth and invasion are still unclear. In this study, we aimed to investigate the role of miR-125b in melanoma progression and metastasis. We found that miR-125b expression is significantly downregulated in primary melanoma, and an even greater downregulation was observed in metastatic invasion. Restored expression of miR-125b in melanoma suppressed cell proliferation and invasion both in vitro and in vivo. Furthermore, our findings demonstrate that upregulating miR-125b significantly inhibits malignant phenotypes by repressing the expression of integrin alpha9 (ITGA9). Finally, our data reveal that upregulated expression of ITGA9 in melanoma tissues is inversely associated with miR-125b levels. Together, our results demonstrate that upregulation of ITGA9 in response to the decrease in miR-125b in metastatic melanoma is responsible for melanoma tumor cell migration and invasion.

Progress on the relationship between miR-125 family and tumorigenesis

miRNA-125 family, which is a highly conserved miRNA family throughout evolution, is consist of miRNA-125a-3p, miRNA-125a-5p, miRNA-125b-1 and miRNA-125b-2.The aberrant expression of miR-125 familyis tightly related to tumorigenesis and tumor development. The downstream targets of miRNA-125 include transcription factors like STAT3, cytokines like IL-6 and TGF-β, tumor suppressing protein p53, pro-apoptotic protein Bak1 and RNA binding protein HuR et al. Through regulating these downstream targets miR-125 family is involved in regulating tumorigenesis and tumor development. Nowadays, miR-125b have already became a putative and valuable biomarker for cancer diagnosis, treatment and prognosis. In this review, we mainly summarize the dual function of miRNA-125 family in suppression and promotion of cancer cells and further elaborate its regulatory mechanisms from four facets, proliferation, apoptosis, invasion or metastasis and immune response.

MicroRNAs in melanocyte and melanoma biology

The importance of microRNAs as key molecular components of cellular processes is now being recognized. Recent reports have shown that microRNAs regulate processes as diverse as protein expression and nuclear functions inside cells and are able to signal extracellularly, delivered via exosomes, to influence cell fate at a distance. The versatility of microRNAs as molecular tools inspires the design of novel strategies to control gene expression, protein stability, DNA repair and chromatin accessibility that may prove very useful for therapeutic approaches due to the extensive manageability of these small molecules. However, we still lack a comprehensive understanding of the microRNA network and its interactions with the other layers of regulatory elements in cellular and extracellular functions. This knowledge may be necessary before we exploit microRNA versatility in therapeutic settings. To identify rules of interactions between microRNAs and other regulatory systems, we begin by reviewing microRNA activities in a single cell type: the melanocyte, from development to disease.