miR-204-5p and miR-211-5p Contribute to BRAF Inhibitor Resistance in Melanoma

Exosomal miR-19a derived from melanoma cell promotes the vemurafenib resistance of malignant melanoma through directly targeting LRIG1 to reactivate AKT and MAPK pathway

Exosomes derived from neighboring v-raf murine sarcoma viral oncogene homolog B1 inhibitor (BRAFi)-resistant melanoma cells mediate the formation of resistance in melanoma cells sensitive to BRAFi. The function and molecular mechanisms of exosomal miRNA in BRAFi resistance of melanoma have not been studied. We found that the expression of miR-19a in BRAFi resistant melanoma cells was significantly higher than that in sensitive cells, and miR-19a contributes to the resistance of melanoma cells to BRAFi by targeting immunoglobulin-like domains protein 1 (LRIG1). miR-19a was highly enriched in exosomes secreted from BRAFi resistant melanoma cells, and these exosomal miR-19a promote the spread of BRAFi resistant. The reactivation of Protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) pathways is the main reason for the BRAFi resistant of melanoma cells. We demonstrated that exosomal miR-19a derived from melanoma cell promotes the formation and spread of BRAFi resistant in melanoma through targeting LRIG1 to reactivate AKT and MAPK pathway. Therefore, miR-19a may serve as a potential therapeutic target in melanoma patients with acquired drug resistance.

MicroRNA-204-5p Attenuates Oxidative Stress, Apoptosis and Inflammation by Targeting TXNIP in Diabetic Cataract

Diabetic cataract (DC) is a major cause of blindness in diabetic patients and it is characterized by early onset and rapid progression. MiR-204-5p was previously identified as one of the top five down-regulated miRNAs in human DC lens tissues. We aimed to determine the expression of miR-204-5p in human lens epithelial cells (HLECs) and explore its effects and mechanisms in regulating the progression of DC. The expression of miR-204-5p in the anterior capsules of DC patients and HLECs was examined by RT-qPCR. Bioinformatics tools were then used to identify the potential target of miR-204-5p. The relationship between miR-204-5p and the target gene was confirmed through a dual luciferase reporter assay. Additionally, the regulatory mechanism of oxidative stress, apoptosis, and inflammation in DC was investigated by overexpressing miR-204-5p using miR-204-5p agomir. The expression of miR-204-5p was downregulated in the anterior capsules of DC patients and HLECs. Overexpression of miR-204-5p reduced ROS levels, pro-apoptosis genes (Bid, Bax, caspase-3), and IL-1β production in HG-treated HLECs. TXNIP was the direct target of miR-204-5p by dual luciferase reporter assay. Therefore, this study demonstrated that miR-204-5p effectively reduced oxidative damage, apoptosis, and inflammation in HLECs under HG conditions by targeting TXNIP. Targeting miR-204-5p could be a promising therapeutic strategy for the potential treatment of DC.

Current State of Melanoma Therapy and Next Steps: Battling Therapeutic Resistance

Melanoma is the most aggressive and deadly form of skin cancer due to its high propensity to metastasize to distant organs. Significant progress has been made in the last few decades in melanoma therapeutics, most notably in targeted therapy and immunotherapy. These approaches have greatly improved treatment response outcomes; however, they remain limited in their abilities to hinder disease progression due, in part, to the onset of acquired resistance. In parallel, intrinsic resistance to therapy remains an issue to be resolved. In this review, we summarize currently available therapeutic options for melanoma treatment and focus on possible mechanisms that drive therapeutic resistance. A better understanding of therapy resistance will provide improved rational strategies to overcome these obstacles.

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.

Unraveling the role of Xist RNA in cardiovascular pathogenesis

Understanding the molecular pathways behind cardiovascular illnesses is crucial due to the enormous worldwide health burden they impose. New insights into the role played by Xist (X-inactive specific transcript) RNA in the onset and progression of cardiovascular diseases have emerged from recent studies. Since its discovery, Xist RNA has been known for its role in X chromosome inactivation during embryogenesis; however, new data suggest that its function extends well beyond the control of sex chromosomes. The regulatory roles of Xist RNA are extensive, encompassing epigenetic changes, gene expression, cellular identity, and sex chromosomal inactivation. There is potential for the involvement of this complex regulatory web in a wide range of illnesses, including cardiovascular problems. Atherosclerosis, hypertrophy, and cardiac fibrosis are all conditions linked to dysregulation of Xist RNA expression. Alterations in DNA methylation and histones are two examples of epigenetic changes that Xist RNA orchestrates, leading to modifications in gene expression patterns in different cardiovascular cells. Additionally, Xist RNA has been shown to contribute to the development of cardiovascular illnesses by modulating endothelial dysfunction, inflammation, and oxidative stress responses. New treatment approaches may become feasible with a thorough understanding of the complex function of Xist RNA in cardiovascular diseases. By focusing on Xist RNA and the regulatory network with which it interacts, we may be able to slow the progression of atherosclerosis, cardiac hypertrophy, and fibrosis, thereby opening novel therapeutic options for cardiovascular diseases amenable to precision medicine. This review summarizes the current state of knowledge concerning the impact of Xist RNA in cardiovascular disorders.

Cutaneous Melanoma: A Review of Multifactorial Pathogenesis, Immunohistochemistry, and Emerging Biomarkers for Early Detection and Management

Cutaneous melanoma (CM) is an increasingly significant public health concern. Due to alarming mortality rates and escalating incidence, it is crucial to understand its etiology and identify emerging biomarkers for improved diagnosis and treatment strategies. This review aims to provide a comprehensive overview of the multifactorial etiology of CM, underscore the importance of early detection, discuss the molecular mechanisms behind melanoma development and progression, and shed light on the role of the potential biomarkers in diagnosis and treatment. The pathogenesis of CM involves a complex interplay of genetic predispositions and environmental exposures, ultraviolet radiation exposure being the predominant environmental risk factor. The emergence of new biomarkers, such as novel immunohistochemical markers, gene mutation analysis, microRNA, and exosome protein expressions, holds promise for improved early detection, and prognostic and personalized therapeutic strategies.

USP18 enhances the resistance of BRAF-mutated melanoma cells to vemurafenib by stabilizing cGAS expression to induce cell autophagy

This study aims to discern the possible molecular mechanism of the effect of ubiquitin-specific peptidase 18 (USP18) on the resistance to BRAF inhibitor vemurafenib in BRAF V600E mutant melanoma by regulating cyclic GMP-AMP synthase (cGAS). The cancer tissues of BRAF V600E mutant melanoma patients before and after vemurafenib treatment were collected, in which the protein expression of USP18 and cGAS was determined. A BRAF V600E mutant human melanoma cell line (A2058R) resistant to vemurafenib was constructed with its viability, apoptosis, and autophagy detected following overexpression and depletion assays of USP18 and cGAS. Xenografted tumors were transplanted into nude mice for in vivo validation. Bioinformatics analysis showed that the expression of cGAS was positively correlated with USP18 in melanoma, and USP18 was highly expressed in melanoma. The expression of cGAS and USP18 was up-regulated in cancer tissues of vemurafenib-resistant patients with BRAF V600E mutant melanoma. Knockdown of cGAS inhibited the resistance to vemurafenib in A2058R cells and the protective autophagy induced by vemurafenib in vitro. USP18 could deubiquitinate cGAS to promote its protein stability. In vivo experimentations confirmed that USP18 promoted vemurafenib-induced protective autophagy by stabilizing cGAS protein, which promoted resistance to vemurafenib in BRAF V600E mutant melanoma cells. Collectively, USP18 stabilizes cGAS protein expression through deubiquitination and induces autophagy of melanoma cells, thereby promoting the resistance to vemurafenib in BRAF V600E mutant melanoma.

Validation of a microRNA liquid biopsy assay for diagnosis and risk stratification of invasive cutaneous melanoma

BACKGROUND

Noninvasive molecular biomarkers are needed to improve the early, accurate and precise diagnosis of invasive cutaneous melanoma.

OBJECTIVES

To independently validate a previously identified circulating microRNA signature of melanoma (MEL38), and, secondly, to develop a complementary microRNA signature, optimized for prognostication.

PATIENTS AND METHODS

MicroRNA expression profiling was performed on plasma samples from a multicentre observational case-control study, involving patients with primary or metastatic melanoma, melanoma in situ, nonmelanoma skin cancer, or benign naevi. MicroRNA profiles from patients with length of survival, treatment and sentinel lymph node biopsy (SLNB) data were used to develop the prognostic signature. The primary outcome of interest for MEL38 was its association with melanoma status, including area under the curve, binary diagnostic sensitivity and specificity, and incidence-adjusted positive and negative predictive values. The prognostic signature was assessed using rates of survival per risk group and relationship to conventional predictors of outcome.

RESULTS

Circulating microRNA profiles of 372 patients with invasive melanoma and 210 control individuals were generated. The average age of all participants was 59 years; 49% were male. A MEL38 score > 5.5 indicated the presence of invasive melanoma. Overall, 551/582 (95%) of patients were correctly diagnosed, with 93% sensitivity and 98% specificity. MEL38 score ranged from 0 to 10 with an area under the curve of 0.98 (95% confidence interval 0.97-0.99, P < 0.001). A novel prognostic 12-microRNA signature (MEL12) developed from 232 patients identified low-, standard- or high-risk groups, with 94%, 78% and 58% rates of 10-year melanoma-specific survival, respectively (log-rank P < 0.001). MEL12 prognostic risk groups were significantly associated with clinical staging (χ2, P < 0.001) and SLNB status (P = 0.027). Patients who were classified as high risk by MEL12 were approximately three times more likely to have melanoma detected in their sentinel lymph nodes compared to low-risk patients.

CONCLUSIONS

The circulating MEL38 signature may assist in diagnosing patients with invasive melanoma vs. other conditions associated with a lower - or negligible - risk of mortality. A complementary and prognostic MEL12 signature is predictive of SLNB status, clinical stage and probability of survival. Plasma microRNA profiling may help to optimize existing diagnostic pathways as well as enable personalized, risk-informed melanoma treatment decisions.

BRAF Mutations in Melanoma: Biological Aspects, Therapeutic Implications, and Circulating Biomarkers

Melanoma is an aggressive form of skin cancer resulting from the malignant transformation of melanocytes. Recent therapeutic approaches, including targeted therapy and immunotherapy, have improved the prognosis and outcome of melanoma patients. BRAF is one of the most frequently mutated oncogenes recognised in melanoma. The most frequent oncogenic BRAF mutations consist of a single point mutation at codon 600 (mostly V600E) that leads to constitutive activation of the BRAF/MEK/ERK (MAPK) signalling pathway. Therefore, mutated BRAF has become a useful target for molecular therapy and the use of BRAF kinase inhibitors has shown promising results. However, several resistance mechanisms invariably develop leading to therapeutic failure. The aim of this manuscript is to review the role of BRAF mutational status in the pathogenesis of melanoma and its impact on differentiation and inflammation. Moreover, this review focuses on the mechanisms responsible for resistance to targeted therapies in BRAF-mutated melanoma and provides an overview of circulating biomarkers including circulating tumour cells, circulating tumour DNA, and non-coding RNAs.

BRAF V600-Mutated Metastatic Melanoma and Targeted Therapy Resistance: An Update of the Current Knowledge

Melanoma is the most common cause of death in skin cancer due to its high metastatic potential. While targeted therapies have improved the care of patients with metastatic melanoma harboring the BRAFV600E mutation, these treatments are associated with a high frequency of resistance. Resistance factors are related to cellular adaptation as well as to changes in the tumor microenvironment. At the cellular level, resistance involves mutations, overexpression, activation, or inhibition of effectors involved in cell signaling pathways such as MAPK, PI3K/AKT, MITF, and epigenetic factors (miRNAs). In addition, several components of the melanoma microenvironment, such as soluble factors, collagen, and stromal cells also play a crucial role in this resistance. In fact, extracellular matrix remodeling impacts the physical and chemical properties with changes in the stiffness and acidity, respectively of the microenvironment. The cellular and immune components of the stroma are also affected, including immune cells and CAF. The aim of this manuscript is to review the mechanisms responsible for resistance to targeted therapies in BRAFV600E-mutated metastatic melanoma.

Critical Considerations for Investigating MicroRNAs during Tumorigenesis: A Case Study in Conceptual and Contextual Nuances of miR-211-5p in Melanoma

MicroRNAs are non-coding RNAs fundamental to metazoan development and disease. Although the aberrant regulation of microRNAs during mammalian tumorigenesis is well established, investigations into the contributions of individual microRNAs are wrought with conflicting observations. The underlying cause of these inconsistencies is often attributed to context-specific functions of microRNAs. We propose that consideration of both context-specific factors, as well as underappreciated fundamental concepts of microRNA biology, will permit a more harmonious interpretation of ostensibly diverging data. We discuss the theory that the biological function of microRNAs is to confer robustness to specific cell states. Through this lens, we then consider the role of miR-211-5p in melanoma progression. Using literature review and meta-analyses, we demonstrate how a deep understating of domain-specific contexts is critical for moving toward a concordant understanding of miR-211-5p and other microRNAs in cancer biology.

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.

Sodium thiosulfate inhibits epithelial-mesenchymal transition in melanoma via regulating the Wnt/β-catenin signaling pathway

BACKGROUND

Melanoma is the most common form of skin cancer. Given its high metastasis and high recurrence, its therapies are constantly updated.

OBJECTIVE

The study aims to prove the efficacy of sodium thiosulfate (STS), an antidote to cyanide or nitroprusside poisoning, in melanoma treatment.

METHODS

We tested the effect of STS by culturing melanoma cells (B16 and A375) in vitro and establishing melanoma mouse models in vivo. The proliferation and viability of melanoma cells were measured by the CCK-8 test, cell cycle assay, apoptosis analysis, wound healing assay, and transwell migration assay. The expression of apoptosis-related molecules, epithelial-mesenchymal transition (EMT)-associated molecules, and the Wnt/β-catenin signaling pathway-related molecules were determined by Western blotting and immunofluorescence.

RESULTS

The high metastasis of melanoma is considered to be linked to the EMT process. The scratch assay using B16 and A375 cells also showed that STS could inhibit the EMT process of melanoma. We demonstrated that STS inhibited the proliferation, viability, and EMT process of melanoma by releasing H₂S. STS-mediated weakening of cell migration was related to the inhibition of the Wnt/β-catenin signaling pathway. Mechanistically, we defined that STS inhibited the EMT process via the Wnt/β-catenin signaling pathway.

CONCLUSIONS

These results suggest that the negative effect of STS on melanoma development is mediated by the reduction of EMT via the regulation of the Wnt/β-catenin signaling pathway, which provides a new clue to treating melanoma.

Oncosuppressive miRNAs loaded in lipid nanoparticles potentiate targeted therapies in BRAF-mutant melanoma by inhibiting core escape pathways of resistance

BRAF-mutated melanoma relapsing after targeted therapies is an aggressive disease with unmet clinical need. Hence the need to identify novel combination therapies able to overcome drug resistance. miRNAs have emerged as orchestrators of non-genetic mechanisms adopted by melanoma cells to challenge therapies. In this context we previously identified a subset of oncosuppressor miRNAs downregulated in drug-resistant melanomas. Here we demonstrate that lipid nanoparticles co-encapsulating two of them, miR-199-5p and miR-204-5p, inhibit tumor growth both in vitro and in vivo in combination with target therapy and block the development of drug resistance. Mechanistically they act by directly reducing melanoma cell growth and also indirectly by hampering the recruitment and reprogramming of pro-tumoral macrophages. Molecularly, we demonstrate that the effects on macrophages are mediated by the dysregulation of a newly identified miR-204-5p-miR-199b-5p/CCL5 axis. Finally, we unveiled that M2 macrophages programs are molecular signatures of resistance and predict response to therapy in patients. Overall, these findings have strong translational implications to propose new combination therapies making use of RNA therapeutics for metastatic melanoma patients.

Role of miRNA in Melanoma Development and Progression

Melanoma is one of the most aggressive and progressive skin cancers. It develops from normal pigment-producing cells known as melanocytes, so it is important to know the mechanism behind such transformations. The study of metastasis mechanisms is crucial for a better understanding the biology of neoplastic cells. Metastasis of melanoma, or any type of cancer, is a multi-stage process in which the neoplastic cells leave the primary tumour, travel through the blood and/or lymphatic vessels, settle in distant organs and create secondary tumours. MicroRNA (miRNA) can participate in several steps of the metastatic process. This review presents the role of miRNA molecules in the development and progression as well as the immune response to melanoma.

EphA3 targeted by miR-3666 contributes to melanoma malignancy via activating ERK1/2 and p38 MAPK pathways

Melanoma is a rare, fatal type of skin tumor. Although EPH receptor A3 (EphA3) is deregulated in melanoma, its detailed role remained uncharacterized. Using real time quantitative PCR analysis and western blotting, EphA3 was identified to be upregulated in melanoma tissues and cells, while miR-3666 showed an opposite expression trend. Cell counting kit-8, scratch wound, and in vivo assays proved that EphA3 silence inhibited the melanoma cell proliferation and migration and retarded tumor growth in vivo. Furthermore, western blotting results displayed that EphA3 silence resulted in a low expression of p38-MAPK and p-ERK1/2. Mechanically, miR-3666 was proved to target EphA3 3'UTR by the luciferase reporter assay. Furthermore, miR-3666 mimic compromised the driven melanoma cell proliferation and migration by EphA3 overexpression. In addition, induction of ERK1/2 and p38 MAPK pathways offset the positive effect of EphA3 overexpression on melanoma cells. In conclusion, miR-3666 downregulated EphA3 expression and retarded melanoma malignancy via inactivating ERK1/2 and p38 MAPK pathways. Hence, miR-3666/EphA3 axis may represent a druggable target against melanoma progression.

Targeting the epigenome in malignant melanoma: Facts, challenges and therapeutic promises

Malignant melanoma is the most lethal type of skin cancer with high rates of mortality. Although current treatment options provide a short-clinical benefit, acquired-drug resistance highlights the low 5-year survival rate among patients with advanced stage of the disease. In parallel, the involvement of an aberrant epigenetic landscape, (e.g., alterations in DNA methylation patterns, histone modifications marks and expression of non-coding RNAs), in addition to the genetic background, has been also associated with the onset and progression of melanoma. In this review article, we report on current therapeutic options in melanoma treatment with a focus on distinct epigenetic alterations and how their reversal, by specific drug compounds, can restore a normal phenotype. In particular, we concentrate on how single and/or combinatorial therapeutic approaches have utilized epigenetic drug compounds in being effective against malignant melanoma. Finally, the role of deregulated epigenetic mechanisms in promoting drug resistance to targeted therapies and immune checkpoint inhibitors is presented leading to the development of newly synthesized and/or improved drug compounds capable of targeting the epigenome of malignant melanoma.

The Roles of MiRNAs (MicroRNAs) in Melanoma Immunotherapy

Melanoma is the most aggressive form of skin cancer, characterized by life-threatening and rapidly spreading progression. Traditional targeted therapy can alleviate tumors by inactivating hyperactive kinases such as BRAF or MEK but inevitably encounters drug resistance. The advent of immunotherapy has revolutionized melanoma treatment and significantly improved the prognosis of melanoma patients. MicroRNAs (miRNAs) are intricately involved in innate and adaptive immunity and are implicated in melanoma immunotherapy. This systematic review describes the roles of miRNAs in regulating the functions of immune cells in skin and melanoma, as well as the involvement of miRNAs in pharmacology including the effect, resistance and immune-related adverse events of checkpoint inhibitors such as PD-1 and CTLA-4 inhibitors, which are used for treating cutaneous, uveal and mucosal melanoma. The expressions and functions of miRNAs in immunotherapy employing tumor-infiltrating lymphocytes and Toll-like receptor 9 agonists are also discussed. The prospect of innovative therapeutic strategies such as the combined administration of miRNAs and immune checkpoint inhibitors and the nanotechnology-based delivery of miRNAs are also provided. A comprehensive understanding of the interplay between miRNAs and immunotherapy is crucial for the discovery of reliable biomarkers and for the development of novel miRNA-based therapeutics against melanoma.

Melanoma: Molecular genetics, metastasis, targeted therapies, immunotherapies, and therapeutic resistance

Cutaneous melanoma is a common cancer and cases have steadily increased since the mid 70s. For some patients, early diagnosis and surgical removal of melanomas is lifesaving, while other patients typically turn to molecular targeted therapies and immunotherapies as treatment options. Easy sampling of melanomas allows the scientific community to identify the most prevalent mutations that initiate melanoma such as the BRAF, NRAS, and TERT genes, some of which can be therapeutically targeted. Though initially effective, many tumors acquire resistance to the targeted therapies demonstrating the need to investigate compensatory pathways. Immunotherapies represent an alternative to molecular targeted therapies. However, inter-tumoral immune cell populations dictate initial therapeutic response and even tumors that responded to treatment develop resistance in the long term. As the protocol for combination therapies develop, so will our scientific understanding of the many pathways at play in the progression of melanoma. The future direction of the field may be to find a molecule that connects all of the pathways. Meanwhile, noncoding RNAs have been shown to play important roles in melanoma development and progression. Studying noncoding RNAs may help us to understand how resistance - both primary and acquired - develops; ultimately allow us to harness the true potential of current therapies. This review will cover the basic structure of the skin, the mutations and pathways responsible for transforming melanocytes into melanomas, the process by which melanomas metastasize, targeted therapeutics, and the potential that noncoding RNAs have as a prognostic and treatment tool.

Current understanding of epigenetics role in melanoma treatment and resistance

Melanoma is the most aggressive form of skin cancer resulting from genetic mutations in melanocytes. Several factors have been considered to be involved in melanoma progression, including genetic alteration, processes of damaged DNA repair, and changes in mechanisms of cell growth and proliferation. Epigenetics is the other factor with a crucial role in melanoma development. Epigenetic changes have become novel targets for treating patients suffering from melanoma. These changes can alter the expression of microRNAs and their interaction with target genes, which involves cell growth, differentiation, or even death. Given these circumstances, we conducted the present review to discuss the melanoma risk factors and represent the current knowledge about the factors related to its etiopathogenesis. Moreover, various epigenetic pathways, which are involved in melanoma progression, treatment, and chemo-resistance, as well as employed epigenetic factors as a solution to the problems, will be discussed in detail.

ERK inactivation enhances stemness of NSCLC cells via promoting Slug-mediated epithelial-to-mesenchymal transition

Rationale: The mitogen-activated protein kinase pathway (MAPK) is one of the major cancer-driving pathways found in non-small cell lung cancer (NSCLC) patients. ERK inhibitors (ERKi) have been shown to be effective in NSCLC patients with MAPK pathway mutations. However, like other MAPK inhibitors, ERKi rarely confers complete and durable responses. The mechanism of tumor relapse after ERKi treatment is yet defined. Methods: To best study the mechanism of tumor relapse after ERK inhibitor treatment in NSCLC patients, we treated various NSCLC cell lines and patient-derived xenograft (PDX) with ERK inhibitors and evaluated the enrichment of cancer stem cell (CSC) population. We then performed a Next-generation sequencing (NGS) to identify potential pathways that are responsible for the CSC enrichment. Further, the involvement of specific pathways was examined using molecular and cellular methods. Finally, we investigated the therapeutic benefits of ERKi treatment combined with JAK/STAT pathway inhibitor using cellular and xenograft NSCLC models. Results: We found that ERKi treatment expands the CSC population in NSCLC cells through enhanced epithelial-to-mesenchymal transition (EMT)-mediated cancer cell dedifferentiation. Mechanistically, ERK inactivation induces EMT via pSTAT3-mediated upregulation of Slug, in which, upregulation of miR-204 and downregulation of SPDEF, a transcription repressor of Slug, are involved. Finally, the JAK/STAT pathway inhibitor Ruxolitinib blocks the ERK inactivation-induced EMT and CSC expansion, as well as the tumor progression in xenograft models after ERKi treatment. Conclusions: This study revealed a potential tumor relapse mechanism of NSCLC after ERK inhibition through the unintended activation of the EMT program, ascertained the pSTAT-miR-204-SPDEF-Slug axis, and provided a promising combination inhibitor approach to prevent tumor relapse in patients.

Dysregulation of miR-204-5p/APLN axis affects malignant progression and cell stemness of esophageal cancer

OBJECTIVE

This study attempted to investigate the mechanism of miR-204-5p and its downstream gene in regulating bio-functions of esophageal cancer (EC).

METHODS

Bioinformatics analysis was performed to select the mature miRNAs, mRNAs, and clinical data of EC. The miRNA-mRNA regulatory axis was predicted through bioinformatics and used Dual-luciferase analysis to verify the interaction between miR-204-5p and APLN. qRT-PCR was applied to analyze expression of miR-204-5p and APLN mRNA. Western blot was utilized to detect APLN protein expression. Functional assays like CCK-8, wound healing, Transwell, and stem cell sphere formation assays were launched to confirm proliferative, migratory, invasive and stemness of cells in different treatment groups.

RESULTS

MiR-204-5p was lowly expressed while its target gene APLN was highly expressed in tumor tissues. Besides, miR-204-5p overexpression hindered proliferation, invasion, migration, and stemness of EC cells. Additionally, dual-luciferase assay verified the interaction of miR-204-5p and APLN. MiR-204-5p could downregulate APLN level and its overexpression reduced the effect of APLN on EC cell functions.

CONCLUSION

Dysregulation of miR-204-5p/APLN axis was linked with malignant progression of EC. MiR-204-5p/APLN may be an underlying candidate for the design of anticarcinogens.

Role of lncSLCO1C1 in gastric cancer progression and resistance to oxaliplatin therapy

BACKGROUND

Gastric carcinoma (GC) is one of the most deadly diseases due to tumour metastasis and resistance to therapy. Understanding the molecular mechanism of tumour progression and drug resistance will improve therapeutic efficacy and develop novel intervention strategies.

METHODS

Differentially expressed long non-coding RNAs (lncRNAs) in clinical specimens were identified by LncRNA microarrays and validated in different clinical cohorts by quantitative real-time polymerase chain reaction (qRT-PCR), in situ hybridisation and bioinformatics analysis. Biological functions of lncRNA were investigated by using cell proliferation assays, migration assays, xenograft tumour models and bioinformatics analysis. Effects of lncSLCO1C1 on GC cell survival were assessed by comet assays and immunofluorescence assays. Underlying molecular mechanisms were further explored by using a number of technologies including RNA pull-down, mass spectrometry analysis, RNA immunoprecipitation, co-immunoprecipitation, miRNA sequencing, luciferase reporter assays and molecular modelling.

RESULTS

LncSLCO1C1 was highly upregulated in GC tissue samples and associated with GC patients' poor overall survival. Overexpression of lncSLCO1C1 promoted proliferation and migration, whereas decreased lncSLCO1C1 expression produced the opposite effects. lncSLCO1C1 also mediated tumour resistance to chemotherapy with oxaliplatin by reducing DNA damage and increasing cell proliferation. Despite sequence overlapping between lncSLCO1C1 and PDE3A, alternations of PDE3A expression had no effect on the GC cell progression, indicating that lncSLCO1C1, not PDE3A, related with the progression of GC cells. Mechanistically, lncSLCO1C1 serves as a scaffold for the structure-specific recognition protein 1 (SSRP1)/H2A/H2B complex and regulates the function of SSRP1 in reducing DNA damage. Meanwhile, lncSLCO1C1 functions as a sponge to adsorb miR-204-5p and miR-211-5p that target SSRP1 mRNA, and thus increases SSRP1 expression. Patients with high expressions of both lncSLCO1C1 and SSRP1 have poor overall survival, highlighting the role of lncSLCO1C1 in GC progression.

CONCLUSIONS

LncSLCO1C1 promotes GC progression by enhancing cell growth and preventing DNA damage via interacting and scaffolding the SSRP1/H2A/H2b complex and absorbing both miR-211-5p and miR-204-5p to increase SSRP1 expression.

Downregulation of miR-211-5p Promotes Carboplatin Resistance in Human Retinoblastoma Y79 Cells by Affecting the GDNF-LIF Interaction

Purpose

To investigate the role of the miR-211-5p-GDNF signaling pathway in carboplatin resistance of retinoblastoma Y79 cells and what factors it may be affected by.

Methods

A carboplatin-resistant retinoblastoma cell line (Y79R) was established in vitro. RNA-seq and microRNA-seq were constructed between Y79 and Y79R cells. RNA interference, RT-PCR, Western blot (WB), and flow cytometry were used to verify the expression of genes and proteins between the two cell lines. The TargetScan database was used to predict the microRNAs that regulate the target genes. STING sites and Co-Immunoprecipitation (COIP) were used to study protein–protein interactions.

Results

GDNF was speculated to be the top changed gene in the drug resistance in Y79R cell lines. Moreover, the speculation was verified by subsequent RT-PCR and WB results. When the expression of GDNF was knocked down, the IC50 of the Y79R cell line significantly reduced. GDNF was found to be the target gene of miR-211-5p. Downregulation of miR-211-5p promotes carboplatin resistance in human retinoblastoma Y79 cells. MiR-211-5p can regulate the expression of GDNF. Our further research also found that GDNF can bind to LIF which is also a secreted protein.

Conclusion

Our results suggest that downregulation of miR-211-5p promotes carboplatin resistance in human retinoblastoma Y79 cells, and this process can be affected by GDNF–LIF interaction. These results can provide evidence for the reversal of drug resistance of RB.

TRIB2 regulates the expression of miR‑33a‑5p through the ERK/c‑Fos pathway to affect the imatinib resistance of chronic myeloid leukemia cells

Chronic myeloid leukemia (CML) is a hematological disease, and imatinib (IM) resistance represents a major problem for its clinical treatment. In the present study, the role of tribbles pseudokinase 2 (TRIB2) in IM resistance of CML and the possible mechanism were investigated. It was found that TRIB2 was highly expressed in IM-resistant patients with CML through the Oncomine database and this conclusion was confirmed using reverse transcription-quantitative PCR and western blot experiments. Knockdown of TRIB2 was found to increase the drug sensitivity of KG cells to IM using Cell-Counting Kit-8 (CCK-8) assays, and the low-expression TRIB2 mice were further found to be more sensitive to the IM and have a higher survival rate in leukemia model mice. Moreover, using western blot and luciferase experiments, it was found that TRIB2 could regulate c-Fos through the ERK signaling pathway, and c-Fos suppressed the transcriptional activity and the expression of miR-33a-5p. Further investigation identified that the binding site for c-Fos to function on miR-33a-5p was the -958-965 region. Finally, CCK-8 assays and western blot experiments demonstrated that miR-33a-5p could inhibit the proliferation of KG cells and reduce IM resistance by suppressing the expression of HMGA2. In conclusion, it was demonstrated that TRIB2 regulates miR-33a-5p to reverse IM resistance in CML, which may help identify novel targets and therapeutic strategies for the clinical treatment of IM resistance.

Maternal Exercise Programs Glucose and Lipid Metabolism and Modulates Hepatic miRNAs in Adult Male Offspring

Detrimental exposures in mothers are recognized as risk factors for the development of metabolic dysfunction in offspring. In contrast, maternal exercise has been reported to be an effective strategy to maintain offspring health. However, the mechanisms underlying the protective effects of maternal exercise on adult offspring metabolic homeostasis are largely unclear. This study aims to investigate whether maternal exercise before and during pregnancy could combat the adverse effects of maternal high-fat diet (HFD) on metabolism in 24-week-old male offspring and to explore the role of miRNAs in mediating the effects. Female C57BL/6 mice were fed with either control diet or HFD 3-week prior to breeding and throughout pregnancy and lactation, among whom half of the HFD-fed mice were submitted to voluntary wheel running training 3-week before and during pregnancy. Male offspring were sedentary and fed with a control diet from weaning to 24 weeks. Body weight, the content of inguinal subcutaneous adipose tissue and perirenal visceral adipose tissue, glucose tolerance, and serum insulin and lipids in offspring were analyzed. Hepatic tissues were collected for transcriptome and miRNA sequencing and reverse transcription-quantitative polymerase chain reaction validation. The results showed that maternal HFD resulted in significant glucose intolerance, insulin resistance, and dyslipidemia in adult offspring, which were negated by maternal exercise. Transcriptome sequencing showed that maternal exercise reversed perinatal HFD-regulated genes in adult offspring, which were enriched in glucose and lipid metabolic-related signaling pathways. At the same time, maternal exercise significantly rescued the changes in the expression levels of 3 hepatic miRNAs in adult offspring, and their target genes were involved in the regulation of cholesterol biosynthesis and epigenetic modification, which may play an important role in mediating the intergenerational metabolic regulation of exercise. Overall, our research pioneered the role of miRNAs in mediating the programming effects of maternal exercise on adult offspring metabolism, which might provide novel insight into the prevention and treatment of metabolic disorders in early life.

Identification of novel rheumatoid arthritis-associated MiRNA-204-5p from plasma exosomes

Rheumatoid arthritis (RA) is an autoimmune disease characterized by infiltration of immune cells in the synovium. However, the crosstalk of immune cells and synovial fibroblasts is still largely unknown. Here, global miRNA screening in plasma exosomes was carried out with a custom microarray (RA patients vs. healthy controls = 9:9). A total of 14 exosomal miRNAs were abnormally expressed in the RA patients. Then, downregulated expression of exosomal miR-204-5p was confirmed in both the replication (RA patients vs. healthy controls = 30:30) and validation groups (RA patients vs. healthy controls = 56:60). Similar to the findings obtained in humans, a decreased abundance of exosomal miR-204-5p was observed in mice with collagen-induced arthritis (CIA). Furthermore, Spearman correlation analysis indicated that plasma exosomal miR-204-5p expression was inversely correlated with disease parameters of RA patients, such as rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein. In vitro, our data showed that human T lymphocytes released exosomes containing large amounts of miR-204-5p, which can be transferred into synovial fibroblasts, inhibiting cell proliferation. Overexpression of miR-204-5p in synovial fibroblasts suppressed synovial fibroblast activation by targeting genes related to cell proliferation and invasion. In vivo assays found that administration of lentiviruses expressing miR-204-5p markedly alleviated the disease progression of the mice with CIA. Collectively, this study identified a novel RA-associated plasma exosomal miRNA-204-5p that mediates the communication between immune cells and synovial fibroblasts and can be used as a potential biomarker for RA diagnosis and treatment.

A microRNA that is significantly reduced in joint tissues in rheumatoid arthritis could provide a therapeutic target and act as a biomarker for disease progression. In rheumatoid arthritis, immune cells release exosomes, tiny vesicles containing microRNA and proteins that are transferred to cells in the synovium, the connective tissue lining the inside of the joint capsule. This transfer of molecules influences synovial cell activity. Shu-Feng Lei and Fei-Yan Deng at the Medical School of Soochow University, Suzhou, China, and co-workers identifed exosomal microRNAs present in rheumatoid arthritis, and examined their effect on synovial cells. Levels of one exosomal microRNA, miR-204-5p, were significantly lower in patient samples and mice models, inversely correlating with disease severity. The team believe that chronic inflammation may suppress levels of miR-204-5p. Treatment boosting microRNA levels in mice models slowed disease progression.

miR-204-5p is sponged by TUG1 to aggravate neuron damage induced by focal cerebral ischemia and reperfusion injury through upregulating COX2

Studies have reported that miR-204-5p is involved in multiple biological processes. However, little is known about the expression and mechanism of miR-204-5p in cerebral ischemia and reperfusion injury. This study found that miR-204-5p expression was significantly downregulated in the blood of patients with ischemic stroke, MCAO/R rat brains, and OGD/R neurons. Overexpression of miR-204-5p markedly reduced infarct volume and neurological impairment and alleviated the inflammatory response in vivo. miR-204-5p promoted neuronal viability and reduced apoptotic cells in vitro. Mechanically, miR-204-5p was negatively regulated by the expression lncRNA TUG1 upstream and down-regulated COX2 expression downstream. Therefore, the TUG1/miR-204-5p/COX2 axis was involved in ischemia and reperfusion-induced neuronal damage. This finding may provide a novel strategy for the treatment of cerebral ischemia and reperfusion injury.

mir-204-5p Acts as a Tumor Suppressor by Targeting DNM2 in Osteosarcoma Cells

Osteosarcoma is a malignant bone tumor composed of interstitial cells. We aim to seek the function of mir-204-5p/DNM2 in osteosarcoma cells. From April 2017 to August 2019, 58 cases of cancer tissues and paracancer tissues were obtained from patients with osteosarcoma in our hospital. qPCR was used to detect mir-204-5p in excisional cancer tissues and paracarcinoma tissues of osteosarcoma patients. The overexpression vector of mir-204-5p was established and transfected into osteosarcoma cells, and the propagation, invasiveness, migration, and apoptosis of osteosarcoma cells were observed. StarBase was employed to forecast the binding site of mir-204-5p and DNM2. The targeting connection of mir-204-5p with DNM2 was detected via double luciferase reporter gene. mir-204-5p was lessened in osteosarcoma (p < 0.05). mir-204-5p overexpression suppressed propagation and accelerated apoptosis of osteosarcoma cells (p < 0.05). The results of double luciferase reporter gene revealed that the fluorescence activity of mir-204-5p was obviously declined when binding to DNM2 (p < 0.05). mir-204-5p functions as a tumor inhibitor by targeting DNM2 in osteosarcoma cells. Our research is helpful to provide new ideas for clinical treatment.

Cytoskeletal Remodelling as an Achilles’ Heel for Therapy Resistance in Melanoma

Melanoma is an aggressive skin cancer with a poor prognosis when diagnosed late. MAPK-targeted therapies and immune checkpoint blockers benefit a subset of melanoma patients; however, acquired therapy resistance inevitably arises within a year. In addition, some patients display intrinsic (primary) resistance and never respond to therapy. There is mounting evidence that resistant cells adapt to therapy through the rewiring of cytoskeleton regulators, leading to a profound remodelling of the actomyosin cytoskeleton. Importantly, this renders therapy-resistant cells highly dependent on cytoskeletal signalling pathways for sustaining their survival under drug pressure, which becomes a vulnerability that can be exploited therapeutically. Here, we discuss the current knowledge on cytoskeletal pathways involved in mainly targeted therapy resistance and future avenues, as well as potential clinical interventions.

High-dose VitC plus oncolytic adenoviruses enhance immunogenic tumor cell death and reprogram tumor immune microenvironment

Preclinical and clinical studies have validated the antitumor effects of several oncolytic viruses (OVs). However, the efficacy of OVs is limited when they are administered as monotherapies. Combination therapy is a promising direction for oncolytic virotherapy in the future. A high dose of vitamin C (VitC) exerts anticancer effects by triggering the accretion of substantial amounts of reactive oxygen species (ROS). OVs can induce immunogenic tumor cell death and elicit an antitumor immune response. ROS play an important role in immunogenic cell death (ICD). This study aimed to explore whether high-dose VitC in combination with oncolytic adenoviruses (oAds) exhibited a synergistic antitumor effect. High-dose VitC synergized with oAds against tumor by enhancing immunogenic tumor cell death. Combination therapy with high-dose VitC and oAds significantly increased the number of T cells in the tumor microenvironment (TME) and promoted the activation of T cells. Furthermore, the antitumor effect of the combination therapy was CD8⁺ T cell dependent. In addition, combination therapy with high-dose VitC and oAds reprogramed the immunosuppressive TME. Our study provides a new strategy for combination therapy of OVs.

MicroRNA Alterations Induced in Human Skin by Diesel Fumes, Ozone, and UV Radiation

Epigenetic alterations are a driving force of the carcinogenesis process. MicroRNAs play a role in silencing mutated oncogenes, thus defending the cell against the adverse consequences of genotoxic damages induced by environmental pollutants. These processes have been well investigated in lungs; however, although skin is directly exposed to a great variety of environmental pollutants, more research is needed to better understand the effect on cutaneous tissue. Therefore, we investigated microRNA alteration in human skin biopsies exposed to diesel fumes, ozone, and UV light for over 24 h of exposure. UV and ozone-induced microRNA alteration right after exposure, while the peak of their deregulations induced by diesel fumes was reached only at the end of the 24 h. Diesel fumes mainly altered microRNAs involved in the carcinogenesis process, ozone in apoptosis, and UV in DNA repair. Accordingly, each tested pollutant induced a specific pattern of microRNA alteration in skin related to the intrinsic mechanisms activated by the specific pollutant. These alterations, over a short time basis, reflect adaptive events aimed at defending the tissue against damages. Conversely, whenever environmental exposure lasts for a long time, the irreversible alteration of the microRNA machinery results in epigenetic damage contributing to the pathogenesis of inflammation, dysplasia, and cancer induced by environmental pollutants.

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.

Identification of Keratinocyte Differentiation-Involved Genes for Metastatic Melanoma by Gene Expression Profiles

Background

Melanoma is the deadliest type of skin cancer. Until now, its pathological mechanisms, particularly the mechanism of metastasis, remain largely unknown. Our study on the identification of genes in association with metastasis for melanoma provides a novel understanding of melanoma.

Methods

From the Gene Expression Omnibus (GEO) database, the gene expression microarray datasets GSE46517, GSE7553, and GSE8401 were downloaded. We made use of R aiming at analyzing the differentially expressed genes (DEGs) between metastatic and nonmetastatic melanoma. R was also used in differentially expressed miRNA (DEM) data mining from GSE18509, GSE19387, GSE24996, GSE34460, GSE35579, GSE36236, and GSE54492 datasets referring to Li's study. Based on the DEG and DEM data, we performed functional enrichment analysis through the application of the DAVID database. Furthermore, we constructed the protein-protein interaction (PPI) network and established functional modules by making use of the STRING database. Through making use of Cytoscape, the PPI results were visualized. We predicted the targets of the DEMs through applying TargetScan, miRanda, and PITA databases and identified the overlapping genes between DEGs and predicted targets, followed by the construction of DEM-DEG pair network. The expressions of these keratinocyte differentiation-involved genes in Module 1 were identified based on the data from TCGA.

Results

239 DEGs were screened out in all 3 datasets, which were inclusive of 21 positively regulated genes and 218 negatively regulated genes. Based on these 239 DEGs, we finished constructing the PPI network which was formed from 225 nodes and 846 edges. We finished establishing 3 functional modules. And we analyzed 92 overlapping genes and 26 miRNA, including 11 upregulated genes targeted by 11 negatively regulated DEMs and 81 downregulated genes targeted by 15 positively regulated DEMs. As proof of the differential expression of metastasis-associated genes, eleven keratinocyte differentiation-involved genes, including LOR, EVPL, SPRR1A, FLG, SPRR1B, SPRR2B, TGM1, DSP, CSTA, CDSN, and IVL in Module 1, were obviously downregulated in metastatic melanoma tissue in comparison with primary melanoma tissue based on the data from TCGA.

Conclusion

239 melanoma metastasis-associated genes and 26 differentially expressed miRNA were identified in our study. The keratinocyte differentiation-involved genes may take part in melanoma metastasis, providing a latent molecular mechanism for this disease.

Reference Genes for qPCR-Based miRNA Expression Profiling in 14 Human Tissues

MicroRNAs (miRNAs) are promising biomarkers for the diagnosis and prognosis of various diseases. Quantitative PCR is the most frequently used method of measuring expression levels of miRNA. However, the lack of validated reference genes represents the main source of potential bias in results. It is normal practice to use small nuclear RNAs as reference genes; however, they often have variable expression. Researchers tend to prefer the most stable reference genes in each experiment. The review includes reference genes for the following tissue types: gliomas, lung cancer, melanoma, gastric cancer, liver cancer, prostate cancer, breast cancer, thyroid cancer, ovarian cancer, cervical cancer, endometrial cancer, rectal cancer, blood tumors, and placental tissues.

BRAF Inhibitor Resistance in Melanoma: Mechanisms and Alternative Therapeutic Strategies

OPINION STATEMENT

Melanoma is caused by a variety of somatic mutations, and among these mutations, BRAF mutation occurs most frequently and has routinely been evaluated as a critical diagnostic biomarker in clinical practice. The introduction of targeted agents for BRAF-mutant melanoma has significantly improved overall survival in a large proportion of patients. However, there is BRAF inhibitor resistance in most patients, and its mechanisms are complicated and need further clarification. Additionally, treatment approaches to overcome resistance have evolved rapidly, shifting from monotherapy to multimodality treatment, which has dramatically improved patient outcomes in clinical trials and practice. This review highlights the mechanisms of BRAF inhibitor resistance in melanoma and discusses the current state of its therapeutic approaches that can be further explored in clinical practice.

Genomic and Transcriptomic Underpinnings of Melanoma Genesis, Progression, and Metastasis

Melanoma is a deadly skin cancer with rapidly increasing incidence worldwide. The discovery of the genetic drivers of melanomagenesis in the last decade has led the World Health Organization to reclassify melanoma subtypes by their molecular pathways rather than traditional clinical and histopathologic features. Despite this significant advance, the genomic and transcriptomic drivers of metastatic progression are less well characterized. This review describes the known molecular pathways of cutaneous and uveal melanoma progression, highlights recently identified pathways and mediators of metastasis, and touches on the influence of the tumor microenvironment on metastatic progression and treatment resistance. While targeted therapies and immune checkpoint blockade have significantly aided in the treatment of advanced disease, acquired drug resistance remains an unfortunately common problem, and there is still a great need to identify potential prognostic markers and novel therapeutic targets to aid in such cases.

Noncoding RNAs: emerging players in skin cancers pathogenesis

Skin malignancies form in tissues of the skin and are the most frequent cancers in the world, with an increasing incidence and a steady fatality rate. They are classified as melanoma or nonmelanoma cancers, which include basal cell carcinoma and squamous cell carcinoma. Noncoding RNA transcripts have received increased attention after the thorough analysis of the human genome revealed that most of the genomic components are not encoded to protein. MicroRNAs, long noncoding RNAs, and circular RNAs are some of the well-studied types of these noncoding regions. The alteration in any of these members' expression is associated intrinsically with human cancers, including skin malignancies, due to their critical functions in cell processes for normal development. As a result, investigating the noncoding component of the transcriptome opens up the possibility of discovering new therapeutic and diagnostic targets. This review discusses current studies on the involvement of microRNAs, long noncoding RNAs, and circular RNAs in the pathogenesis of human skin cancers.

The Integrative Analysis of Competitive Endogenous RNA Regulatory Networks in Coronary Artery Disease

Background: Coronary artery disease (CAD) is the leading cause of cardiovascular death. The competitive endogenous RNAs (ceRNAs) hypothesis is a new theory that explains the relationship between lncRNAs and miRNAs. The mechanism of ceRNAs in the pathological process of CAD has not been fully elucidated. The objective of this study was to explore the ceRNA mechanism in CAD using the integrative bioinformatics analysis and provide new research ideas for the occurrence and development of CAD.

Methods: The GSE113079 dataset was downloaded, and differentially expressed lncRNAs (DElncRNAs) and genes (DEGs) were identified using the limma package in the R language. Weighted gene correlation network analysis (WGCNA) was performed on DElncRNAs and DEGs to explore lncRNAs and genes associated with CAD. Functional enrichment analysis was performed on hub genes in the significant module identified via WGCNA. Four online databases, including TargetScan, miRDB, miRTarBase, and Starbase, combined with an online tool, miRWalk, were used to construct ceRNA regulatory networks.

Results: DEGs were clustered into ten co-expression modules with different colors using WGCNA. The brown module was identified as the key module with the highest correlation coefficient. 188 hub genes were identified in the brown module for functional enrichment analysis. DElncRNAs were clustered into sixteen modules, including seven modules related to CAD with the correlation coefficient more than 0.5. Three ceRNA networks were identified, including OIP5-AS1-miR-204-5p/miR-211-5p-SMOC1, OIP5-AS1-miR-92b-3p-DKK3, and OIP5-AS1-miR-25-3p-TMEM184B.

Conclusion: Three ceRNA regulatory networks identified in this study may play crucial roles in the occurrence and development of CAD, which provide novel insights into the ceRNA mechanism in CAD.

MicroRNA-Based Risk Score for Predicting Tumor Progression Following Radioactive Iodine Ablation in Well-Differentiated Thyroid Cancer Patients: A Propensity-Score Matched Analysis

Simple Summary

The three-tiered American Thyroid Association (ATA) risk stratification helps clinicians tailor decisions regarding follow-up modalities and the need for postoperative radioactive iodine (RAI) ablation and radiotherapy. However, a significant number of well-differentiated thyroid cancers (DTC) progress after treatment. Current follow-up modalities have also been proposed to detect disease relapse and recurrence but have failed to be sufficiently sensitive or specific to detect, monitor, or determine progression. Therefore, we assessed the predictive accuracy of the microRNA-based risk score in DTC with and without postoperative RAI. We confirm the prognostic role of triad biomarkers (miR-2f04, miR-221, and miR-222) with higher sensitivity and specificity for predicting disease progression than the ATA risk score. Compared to indolent tumors, a higher risk score was found in progressive samples and was associated with shorter survival. Consequently, our prognostic microRNA signature and nomogram provide a clinically practical and reliable ancillary measure to determine the prognosis of DTC patients.

Abstract

To identify molecular markers that can accurately predict aggressive tumor behavior at the time of surgery, a propensity-matching score analysis of archived specimens yielded two similar datasets of DTC patients (with and without RAI). Bioinformatically selected microRNAs were quantified by qRT-PCR. The risk score was generated using Cox regression and assessed using ROC, C-statistic, and Brier-score. A predictive Bayesian nomogram was established. External validation was performed, and causal network analysis was generated. Within the eight-year follow-up period, progression was reported in 51.5% of cases; of these, 48.6% had the T1a/b stage. Analysis showed upregulation of miR-221-3p and miR-222-3p and downregulation of miR-204-5p in 68 paired cancer tissues (p < 0.001). These three miRNAs were not differentially expressed in RAI and non-RAI groups. The ATA risk score showed poor discriminative ability (AUC = 0.518, p = 0.80). In contrast, the microRNA-based risk score showed high accuracy in predicting tumor progression in the whole cohorts (median = 1.87 vs. 0.39, AUC = 0.944) and RAI group (2.23 vs. 0.37, AUC = 0.979) at the cutoff >0.86 (92.6% accuracy, 88.6% sensitivity, 97% specificity) in the whole cohorts (C-statistics = 0.943/Brier = 0.083) and RAI subgroup (C-statistic = 0.978/Brier = 0.049). The high-score group had a three-fold increased progression risk (hazard ratio = 2.71, 95%CI = 1.86–3.96, p < 0.001) and shorter survival times (17.3 vs. 70.79 months, p < 0.001). Our prognostic microRNA signature and nomogram showed excellent predictive accuracy for progression-free survival in DTC.

Identification of prognostic biomarkers related to the tumor microenvironment in thyroid carcinoma

Thyroid Carcinoma (THCA) is the most common endocrine tumor that is mainly treated using surgery and radiotherapy. In addition, immunotherapy is a recently developed treatment option that has played an essential role in the management of several types of tumors. However, few reports exist on the use of immunotherapy to treat THCA. The study downloaded the miRNA, mRNA and lncRNA data for THCA patients from the TCGA database ( https://portal.gdc.cancer.gov/ ). Thereafter, the tumor samples were divided into cold and hot tumors, based on the immune score of the tumor microenvironment. Moreover, the differentially expressed lncRNAs and miRNAs were obtained. Finally, the study jointly constructed a ceRNA network through differential analysis of the mRNA data for cold and hot tumors. The study first assessed the level of immune infiltration in the THCA tumor microenvironment then divided the samples into cold and hot tumors, based on the immune score. Additionally, a total of 568 up-regulated and 412 down-regulated DEGs were screened by analyzing the differences between hot and cold tumors. Thereafter, the study examined the differentially expressed genes for lncRNA and miRNA. The results revealed 629 differentially expressed genes related to lncRNA and 114 associated with miRNA. Finally, a ceRNA network of the differentially expressed genes was constructed. The results showed a five-miRNA hubnet, i.e., hsa-mir-204, hsa-mir-128, hsa-mir-214, hsa-mir-150 and hsa-mir-338. The present study identified the immune-related mRNA, lncRNA and miRNA in THCA then constructed a ceRNA network. These results are therefore important as they provide more insights on the immune mechanisms in THCA. The findings also provides additional information for possible THCA immunotherapy.

MicroRNA-211 attenuates cell proliferation in T-cell lymphoblastic lymphoma through targeting TCF12

T-cell lymphoblastic lymphoma (T-LBL) is a class of highly aggressive hematologic neoplasms originating from progenitor T-lymphocytes. MicroRNA (miRNA) is an endogenous RNA molecule with 22 nucleotides in length. Accumulated evidence suggests that miRNA functions as a key regulator in human cancer. Herein, by in silico analysis, we found that miR-211 was a decreased miRNA in T-LBL in high-throughput sequencing data, which was subsequently verified in our cohort. Low miR-211 was closely correlated with bulky disease, high ann arbor stage, relapse and poor prognosis. miR-211 was regulated by N6-methyladenosine (m⁶A) modification, specifically, m6A methyltransferase METTL14 methylated primary miR-211 (pri-miR-211), expediting pri-miR-211 processing via recruiting DGCR8. Functionally, miR-211 overexpression significantly reduced T-LBL cell viability, DNA synthesis rate and spheroid formation ability, whereas silencing of miR-211 had the opposite effects. In addition, we established the xenograft tumor model and found that miR-211 remarkably inhibited tumor growth in vivo. Further, TCF12 was the direct target of miR-211, miR-211 bound to TCF12 mRNA 3`-untranslated region (UTR) and increased its decay, overexpression of TCF12 could effectively rescue the weakened malignant behavior of T-LBL cells caused by miR-211 overexpression. Collectively, our data clearly demonstrate that miR-211 is a novel tumor suppressor in T-LBL, targeting of miR-211/TCF12 axis may be a potential treatment for T-LBL patients.

Bilirubin Restrains the Anticancer Effect of Vemurafenib on BRAF-Mutant Melanoma Cells Through ERK-MNK1 Signaling

Melanoma, the most threatening cancer in the skin, has been considered to be driven by the carcinogenic RAF-MEK1/2-ERK1/2 signaling pathway. This signaling pathway is usually mainly dysregulated by mutations in BRAF or RAS in skin melanomas. Although inhibitors targeting mutant BRAF, such as vemurafenib, have improved the clinical outcome of melanoma patients with BRAF mutations, the efficiency of vemurafenib is limited in many patients. Here, we show that blood bilirubin in patients with BRAF-mutant melanoma treated with vemurafenib is negatively correlated with clinical outcomes. In vitro and animal experiments show that bilirubin can abrogate vemurafenib-induced growth suppression of BRAF-mutant melanoma cells. Moreover, bilirubin can remarkably rescue vemurafenib-induced apoptosis. Mechanically, the activation of ERK-MNK1 axis is required for bilirubin-induced reversal effects post vemurafenib treatment. Our findings not only demonstrate that bilirubin is an unfavorable for patients with BRAF-mutant melanoma who received vemurafenib treatment, but also uncover the underlying mechanism by which bilirubin restrains the anticancer effect of vemurafenib on BRAF-mutant melanoma cells.

Targeting the p300/NONO axis sensitizes melanoma cells to BRAF inhibitors

BRAF inhibitors (BRAFi) that target BRAF V600E kinase, a driver mutation found in 50% of melanomas, show a significant antitumor response, but the common emergence of acquired resistance remains a challenge. Abnormal expression of RAF isoforms CRAF and ARAF reactivates pERK1/2, which plays crucial roles in the acquisition of resistance of melanoma cells. However, the mechanisms of dysregulation of RAF isoforms in resistant melanoma cells remain unknown. Here, we identified NONO interacted with and stabilized both CRAF and ARAF in melanoma cells, and that NONO was acetylated at 198K by p300 acetyltransferase, which stabilized NONO via antagonizing its ubiquitination/degradation mediated by RNF8. The upregulation of both p300 and NONO promoted the rebound of pERK1/2 and the subsequent resistance of melanoma cells to BRAFi, and the activation of ERK1/2 in turn induced p300 to form a positive feedback loop in resistant melanoma cells. There was a positive correlation between p300 and NONO in resistant melanoma cells and clinical samples, and p300 inhibitor C646 overcame the resistance of resistant melanoma cells to BRAF inhibitors in vitro and in vivo. Our findings reveal that targeting the positive feedback loop of p300-NONO-CRAF/ARAF-pERK1/2 may be excellent strategies to overcome the resistance of BRAF inhibitors for melanoma patients.

BRAF/EZH2 Signaling Represses miR-129-5p Inhibition of SOX4 Thereby Modulating BRAFi Resistance in Melanoma

Simple Summary

Approximately 60% of all melanomas are associated with a constitutive activating BRAF mutation. Inhibition of BRAF downstream signaling by targeted therapies significantly improved patient outcomes. However, most patients eventually develop resistance. Here we identified miR-129-5p as a novel tumor suppressor in BRAF mutated melanoma, which expression is increased during response to BRAF inhibition, but repressed in an EZH2 dependent manner during activated BRAF signaling. Overexpression of miR-129-5p decreases melanoma cell proliferation and improves response to BRAF inhibition by targeting SOX4. Taken together our results emphasize SOX4 as a potential therapeutic target in BRAF driven melanoma which could be attacked by pharmaceutically.

Abstract

Many melanomas are associated with activating BRAF mutation. Targeted therapies by inhibitors of BRAF and MEK (BRAFi, MEKi) show marked antitumor response, but become limited by drug resistance. The mechanisms for this are not fully revealed, but include miRNA. Wishing to improve efficacy of BRAFi and knowing that certain miRNAs are linked to resistance to BRAFi, we wanted to focus on miRNAs exclusively associated with response to BRAFi. We found increased expression of miR-129-5p during BRAFi treatment of BRAF- mutant melanoma cells. Parallel to emergence of resistance we observed mir-129-5p expression to become suppressed by BRAF/EZH2 signaling. In functional analyses we revealed that miR-129-5p acts as a tumor suppressor as its overexpression decreased cell proliferation, improved treatment response and reduced viability of BRAFi resistant melanoma cells. By protein expression analyses and luciferase reporter assays we confirmed SOX4 as a direct target of mir-129-5p. Thus, modulation of the miR-129-5p-SOX4 axis could serve as a promising novel strategy to improve response to BRAFi in melanoma.

miR-204-5p and miR-211 Synergistically Downregulate the αS1-Casein Content and Contribute to the Lower Allergy of Goat Milk

α_S1-Casein (encoded by the CSN1S1 gene) is associated with higher rates of allergy than other milk protein components for humans. microRNAs (miRNAs) as small noncoding RNA molecules regulate gene expression and influence diverse biological processes. However, little is known about the regulation of milk protein synthesis by miRNAs in ruminants. In this study, we aim to investigate the regulatory roles of miR-204 family members (miR-204-5p and miR-211) on α_S1-casein in goat mammary epithelial cells (GMEC). Here, we observed that the CSN1S1 mRNA level is upregulated, while miR-204-5p and miR-211 (miR-204-5p/-211) abundance is downregulated during peak lactation compared with middle lactation of dairy goats. We found that miR-204-5p/-211 synergistically inhibit α_S1-casein expression via directly binding to the 3'-untranslated region (3'UTR) of CSN1S1 in GMEC. miR-204-5p/-211 increase β-casein mRNA (CSN2) and protein abundance, as well as the signal transducer and activator of transcription 5a (STAT5a) activity. Further, miR-204-5p/-211 enhance β-casein expression via the CSN1S1-STAT5a signaling axis and promote β-casein transcription by activating the STAT5 response element located in the CSN2 promoter. In conclusion, miR-204-5p/-211 regulate α_S1-casein and β-casein synthesis via targeting CSN1S1 in GMEC, which provide the strategy for manipulating miR-204 family members to reduce milk allergy potential and improve ruminant milk quality for human consumption.

Many Distinct Ways Lead to Drug Resistance in BRAF- and NRAS-Mutated Melanomas

Advanced melanoma is a relentless tumor with a high metastatic potential. The combat of melanoma by using the targeted therapy is impeded because several major driver mutations fuel its growth (predominantly BRAF and NRAS). Both these mutated oncogenes strongly activate the MAPK (MEK/ERK) pathway. Therefore, specific inhibitors of these oncoproteins or MAPK pathway components or their combination have been used for tumor eradication. After a good initial response, resistant cells develop almost universally and need the drug for further expansion. Multiple mechanisms, sometimes very distant from the MAPK pathway, are responsible for the development of resistance. Here, we review many of the mechanisms causing resistance and leading to the dismal final outcome of mutated BRAF and NRAS therapy. Very heterogeneous events lead to drug resistance. Due to this, each individual mechanism would be in fact needed to be determined for a personalized therapy to treat patients more efficiently and causally according to molecular findings. This procedure is practically impossible in the clinic. Other approaches are therefore needed, such as combined treatment with more drugs simultaneously from the beginning of the therapy. This could eradicate tumor cells more rapidly and greatly diminish the possibility of emerging mechanisms that allow the evolution of drug resistance.

Cul4b Promotes Progression of Malignant Cutaneous Melanoma Patients by Regulating CDKN2A

Although several molecular targeted therapy and immunotherapy have been developed, cutaneous melanoma prognosis is still not satisfying. Cul4b promotes the progression of several malignant tumors by regulating cell proliferation. However, its prognostic role in malignant cutaneous melanoma has not been evaluated. In this study, immunohistochemistry was performed to assess the expression of Cul4b in a consecutive patient cohort. The prognostic role of Cul4b was estimated with univariate and multivariate analysis. Cul4b was knocked down in melanoma cell line to evaluate its role in promoting cell proliferation. The results revealed that Cul4b was highly expressed in some of the cutaneous malignant melanoma patients and high expression of Cul4b was associated with poor melanoma-specific overall survival and poor disease-free survival. Cul4b expression was associated with Breslow categories, Clark level, and Ki67 expression. Univariate and multivariate analysis revealed that Cul4b is an independent prognosis risk factor of cutaneous melanoma. Downregulation of Cul4b inhibited the proliferation ability of melanoma cells and downregulated the expression of CDKN2A. These results suggest that Cul4b plays an essential role in cutaneous melanoma progression and may serve as a promising treatment target.

LncRNA EGOT/miR-211-5p Affected Radiosensitivity of Rectal Cancer by Competitively Regulating ErbB4

BACKGROUND/AIMS

Long non-coding ribonucleic acids (lncRNAs) are involved in the progression of cancers and affect the response to radiation therapy. This study was to investigate the mechanism of lncRNA EGOT in the radiosensitivity of rectal cancer.

METHODS

The mRNA expression of EGOT, miR-211-5p and ErbB4 in rectal cancer tissues and cells was detected by qRT-PCR. The protein expression of ErbB4 was detected by Western blot. Dual-luciferase reporter assay and ribonucleic acid immunoprecipitation (RIP) were used to confirm the interaction between EGOT and miR-211-5p or miR-211-5p and ErbB4. Transfection technology was used to down-regulate and up-regulate the expression of EGOT and miR-211-5p in rectal cancer cells, respectively. MTT, colony formation and flow cytometry were used to detect the effect of EGOT and miR-211-5p on proliferation, invasion, migration and apoptosis of rectal cancer cells.

RESULTS

The expression of EGOT was up-regulated in rectal cancer tissues and cells, and the expression of EGOT was related to the late stage of pathology. EGOT knockdown inhibited the proliferation and colony formation of rectal cancer cells and induced the apoptosis of rectal cancer cells. Moreover, EGOT knockdown was significantly enhanced the effects of radiotherapy on rectal cancer in vivo and in vitro. Furthermore, EGOT was found to serve as a sponge of miR-211-5p, and ErbB4 was a downstream target of miR-211-5p. EGOT enhanced the expression of ErbB4 by regulating miR-211-5p. MiR-211-5p inhibitor restored the effect of EGOT knockdown on the radiosensitivity of rectal cancer.

CONCLUSION

Down-regulation of EGOT could inhibit the growth of rectal cancer cells by regulating the miR-211-5p/ErbB4 axis and improve the radiosensitivity of rectal cancer cells. EGOT may be a new therapeutic target for rectal cancer.