Long non-coding RNA HOTAIR acts as a competing endogenous RNA to promote malignant melanoma progression by sponging miR-152-3p

The role of HOTAIR in the modulation of resistance to anticancer therapy

Leading anti-tumour therapeutic strategies typically involve surgery and radiotherapy for locally advanced (non-metastatic) cancers, while hormone therapy, chemotherapy, and molecular targeted therapy are the current treatment options for metastatic cancer. Despite the initially high sensitivity rate to anticancer therapies, a large number of patients develop resistance, leading to a poor prognosis. The mechanisms related to drug resistance are highly complex, and long non-coding RNAs appear to play a crucial role in these processes. Among these, the lncRNA homeobox transcript antisense intergenic RNA (HOTAIR), widely implicated in cancer initiation and progression, likewise plays a significant role in anticancer drug resistance. It can modulate cell activities such as proliferation, apoptosis, hypoxia, autophagy, as well as epithelial-mesenchymal transition, thereby contributing to the development of resistant tumour cells. In this manuscript, we describe different mechanisms of antitumor drug resistance in which HOTAIR is involved and suggest its potential as a therapeutic predictive biomarker for the management of cancer patients.

Long non-coding RNA as a potential diagnostic and prognostic biomarker in melanoma: A systematic review and meta-analysis

Recently, long noncoding RNAs (lncRNAs) have been applied as biomarkers for melanoma patients. In this systematic review and meta-analysis, we investigated the diagnostic and prognostic value of lncRNAs. We used the keywords 'lncRNA' and 'melanoma' to search databases for studies published before June 14th, 2023. The specificity, sensitivity and AUC were utilized to assess diagnostic accuracy and the prognostic value was assessed using overall survival, progression-free survival and disease-free survival hazard ratios. After screening 1191 articles, we included seven studies in the diagnostic evaluation section and 17 studies in the prognosis evaluation section. The Reitsma bivariate model estimated a cumulative sensitivity of 0.724 (95% CI: 0.659-0.781, p < 0.001) and specificity of 0.812 (95% CI: 0.752-0.859, p < 0.001). The pooled AUC was 0.780 (95% CI: 0.749-0.811, p < 0.0001). The HR for overall survival was 2.723 (95% CI: 2.259-3.283, p < 0.0001). Two studies reported an HR for overall survival less than one, with an HR of 0.348 (95% CI: 0.200-0.607, p < 0.0002). The HR for progression-free survival was 2.913 (95% CI: 2.050-4.138, p < 0.0001). Four studies reported an HR less than one, with an HR of 0.457 (95% CI: 0.256-0.817). The HR for disease-free survival was 2.760 (95% CI: 2.009-3.792, p < 0.0001). In conclusion, the expression of lncRNAs in melanoma patients affects survival and prognosis. LncRNAs can also be employed as diagnostic biomarkers.

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.

miR-224-5p acts as a tumour suppressor and reverses the resistance to BRAF inhibitor in melanoma through directly targeting PAK4 to block the MAPK pathway

miR-224-5p has been shown to play both an oncogene and tumour suppressor role in many human tumours. However, the role and molecular mechanism of miR-224-5p in cutaneous melanoma remains unclear. miR-224-5p levels were downregulated in melanoma tissue, and low miR-224-5p expression was an independent risk factor for melanoma patients. miR-224-5p blocked proliferation, epithelial-to-mesenchymal transition (EMT), invasion, migration in BRAF wild-type melanoma cell, and overcome acquired BRAFi resistance in VMF-resistant melanoma cells. miR-224-5p exerted its role by directly repressing PAK4 to block the downstream CRAF/MEK/ERK pathways. We demonstrated that miR-224-5p inhibited melanoma growth and metastasis in vivo though xenograft tumor and pulmonary metastasis assay. Thus, miR-224-5p/PAK4-mediated CRAF/MEK/ERK pathways have therapeutic potential in melanoma treatment.

Regulatory miRNAs and lncRNAs in Skin Cancer: A Narrative Review

Non-coding RNAs (ncRNAs) have a significant regulatory role in the pathogenesis of skin cancer, despite the fact that protein-coding genes have generally been the focus of research efforts in the field. We comment on the actions of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in the current review with an eye toward potential therapeutic treatments. LncRNAs are remarkably adaptable, acting as scaffolding, guides, or decoys to modify key signaling pathways (i.e., the Wnt/β-catenin pathway) and gene expression. As post-transcriptional gatekeepers, miRNAs control gene expression by attaching to messenger RNAs and causing their degradation or suppression during translation. Cell cycle regulation, cellular differentiation, and immunological responses are all affected by the dysregulation of miRNAs observed in skin cancer. NcRNAs also show promise as diagnostic biomarkers and prognostic indicators. Unraveling the complexity of the regulatory networks governed by ncRNAs in skin cancer offers unprecedented opportunities for groundbreaking targeted therapies, revolutionizing the landscape of dermatologic care.

The PI3K-Akt-mTOR and Associated Signaling Pathways as Molecular Drivers of Immune-Mediated Inflammatory Skin Diseases: Update on Therapeutic Strategy Using Natural and Synthetic Compounds

The dysregulated phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway has been implicated in various immune-mediated inflammatory and hyperproliferative dermatoses such as acne, atopic dermatitis, alopecia, psoriasis, wounds, and vitiligo, and is associated with poor treatment outcomes. Improved comprehension of the consequences of the dysregulated PI3K/Akt/mTOR pathway in patients with inflammatory dermatoses has resulted in the development of novel therapeutic approaches. Nonetheless, more studies are necessary to validate the regulatory role of this pathway and to create more effective preventive and treatment methods for a wide range of inflammatory skin diseases. Several studies have revealed that certain natural products and synthetic compounds can obstruct the expression/activity of PI3K/Akt/mTOR, underscoring their potential in managing common and persistent skin inflammatory disorders. This review summarizes recent advances in understanding the role of the activated PI3K/Akt/mTOR pathway and associated components in immune-mediated inflammatory dermatoses and discusses the potential of bioactive natural products, synthetic scaffolds, and biologic agents in their prevention and treatment. However, further research is necessary to validate the regulatory role of this pathway and develop more effective therapies for inflammatory skin disorders.

HOX cluster-embedded lncRNAs and epithelial-mesenchymal transition in cancer: Molecular mechanisms and therapeutic opportunities

Although there has been substantial improvement in the treatment modalities, cancer remains the major cause of fatality worldwide. Metastasis, recurrence, and resistance to oncological therapies are the leading causes of cancer mortality. Epithelial-mesenchymal transition (EMT) is a complex biological process that allows cancer cells to undergo morphological transformation into a mesenchymal phenotype to acquire invasive potential. It encompasses reversible and dynamic ontogenesis by neoplastic cells during metastatic dissemination. Hence, understanding the molecular landscape of EMT is imperative to identify a reliable clinical biomarker to combat metastatic spread. Accumulating evidence reveals the role of HOX (homeobox) cluster-embedded long non-coding RNAs (lncRNAs) in EMT and cancer metastasis. They play a crucial role in the induction of EMT, modulating diverse biological targets. The present review emphasizes the involvement of HOX cluster-embedded lncRNAs in EMT as a molecular sponge, chromatin remodeler, signaling regulator, and immune system modulator. Furthermore, the molecular mechanisms behind therapy resistance and the potential use of novel drugs targeting HOX cluster-embedded lncRNAs in the clinical management of distant metastasis will be discussed.

Long non-coding RNAs and melanoma: From diagnosis to therapy

Although extremely rare, malignant melanoma is the deadliest type of skin malignancy with the inherent capability to invade other organs and metastasize to distant tissues. In 2021, it was estimated that approximately 106,110 patients may have received the diagnosis of melanoma, with a mortality rate of 7180. Surgery remains the common choice for treatment in patients with melanoma. Despite many advances in the treatment of melanoma, some patients, such as those who have received cytotoxic chemotherapeutic and immunotherapic agents, a significant number of patients may show inadequate treatment response following initiating these treatments. Non-coding RNAs, including lncRNAs, have become recently popular and attracted the attention of many researchers to make new insights into the pathogenesis of many diseases, particularly malignancies. LncRNAs have been thoroughly investigated in multiple cancers such as melanoma and have been shown to play a major role in regulating various physiological and pathological cellular processes. Considering their core regulatory function, these non-coding RNAs may be appropriate candidates for melanoma patients' diagnosis, prognosis, and treatment. In this review, we will cover all the current literature available for lncRNAs in melanoma and will discuss their potential benefits as diagnostic and/or prognostic markers or potent therapeutic targets in the treatment of melanoma patients.

SV40 miR-S1 and Cellular miR-1266 Sequester Each Other from Their Targets, Enhancing Telomerase Activity and Viral Replication

Virus-encoded microRNAs (miRNAs) target viral and host mRNAs to repress protein production from viral and host genes, and regulate viral persistence, cell transformation, and evasion of the immune system. The present study demonstrated that simian virus 40 (SV40)-encoded miRNA miR-S1 targets a cellular miRNA miR-1266 to derepress their respective target proteins, namely, T antigens (Tags) and telomerase reverse transcriptase (TERT). An in silico search for cellular miRNAs to interact with viral miR-S1 yielded nine potential miRNAs, five of which, including miR-1266, were found to interact with miR-S1 in dual-luciferase tests employing reporter plasmids containing the miRNA sequences with miR-S1. Intracellular bindings of miR-1266 to miR-S1 were also verified by the pull-down assay. These miRNAs were recruited into the Ago2-associated RNA-induced silencing complex. Intracellular coexpression of miR-S1 with miR-1266 abrogated the downregulation of TERT and decrease in telomerase activity induced by miR-1266. These effects of miR-S1 were also observed in miR-1266-expressing A549 cells infected with SV40. Moreover, the infected cells contained more Tag, replicated more viral DNA, and released more viral particles than control A549 cells infected with SV40, indicating that miR-S1-induced Tag downregulation was antagonized by miR-1266. Collectively, the present results revealed an interplay of viral and cellular miRNAs to sequester each other from their respective targets. This is a novel mechanism for viruses to manipulate the expression of viral and cellular proteins, contributing to not only viral lytic and latent replication but also cell transformation observed in viral infectious diseases including oncogenesis.

Non-Coding RNAs and Oral Cancer: Small Molecules With Big Functions

Oral cancer remains a major public concern with considerable socioeconomic impact in the world. Despite substantial advancements have been made in treating oral cancer, the five-year survival rate for oral cancer remained undesirable, and the molecular mechanisms underlying OSCC carcinogenesis have not been fully understood. Noncoding RNAs (ncRNAs) include transfer RNAs (tRNAs), as well as small RNAs such as microRNAs, and the long ncRNAs such as HOTAIR are a large segment of the transcriptome that do not have apparent protein-coding roles, but they have been verified to play important roles in diverse biological processes, including cancer cell development. Cell death, such as apoptosis, necrosis, and autophagy, plays a vital role in the progression of cancer. A better understanding of the regulatory relationships between ncRNAs and these various types of cancer cell death is therefore urgently required. The occurrence and development of oral cancer can be controlled by increasing or decreasing the expression of ncRNAs, a method which confers broad prospects for oral cancer treatment. Therefore, it is urgent for us to understand the influence of ncRNAs on the development of different modes of oral tumor death, and to evaluate whether ncRNAs have the potential to be used as biological targets for inducing cell death and recurrence of chemotherapy. The purpose of this review is to describe the impact of ncRNAs on cell apoptosis and autophagy in oral cancer in order to explore potential targets for oral cancer therapy.

Regulation of LncRNAs in Melanoma and Their Functional Roles in the Metastatic Process

Long non-coding RNAs (lncRNAs) are key regulators of numerous intracellular processes leading to tumorigenesis. They are frequently deregulated in cancer, functioning as oncogenes or tumor suppressors. As they act through multiple mechanisms, it is not surprising that they may exert dual functions in the same tumor. In melanoma, a highly invasive and metastatic tumor with the propensity to rapidly develop drug resistance, lncRNAs play different roles in: (i) guiding the phenotype switch and leading to metastasis formation; (ii) predicting the response of melanoma patients to immunotherapy; (iii) triggering adaptive responses to therapy and acquisition of drug resistance phenotypes. In this review we summarize the most recent findings on the lncRNAs involved in melanoma growth and spreading to distant sites, focusing on their role as biomarkers for disease diagnosis and patient prognosis, or targets for novel therapeutic approaches.

The pleiotropic roles of circular and long noncoding RNAs in cutaneous melanoma

Cutaneous melanoma (CM) is a very aggressive disease, often characterized by unresponsiveness to conventional therapies and high mortality rates worldwide. The identification of the activating BRAFV600 mutations in approximately 50% of CM patients has recently fueled the development of novel small-molecule inhibitors that specifically target BRAFV600 -mutant CM. In addition, a major progress in CM treatment has been made by monoclonal antibodies that regulate the immune checkpoint inhibitors. However, although target-based therapies and immunotherapeutic strategies have yielded promising results, CM treatment remains a major challenge. In the last decade, accumulating evidence points to the aberrant expression of different types of noncoding RNAs (ncRNAs) in CM. While studies on microRNAs have grown exponentially leading to significant insights on CM biology, the role of circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs) in this tumor is less understood, and much remains to be discovered. Here, we summarize and critically review the available evidence on the molecular functions of circRNAs and lncRNAs in BRAFV600 -mutant CM and CM immunogenicity, providing recent updates on their functional role in targeted therapy and immunotherapy resistance. In addition, we also include an evaluation of several algorithms and databases for prediction and validation of circRNA and lncRNA functional interactions.

Epigenetic Changes and Functions in Pneumoconiosis

Pneumoconiosis is one of the most common occupational diseases in the world, and specific treatment methods of pneumoconiosis are lacking at present, so it carries great social and economic burdens. Pneumoconiosis, coronavirus disease 2019, and idiopathic pulmonary fibrosis all have similar typical pathological changes-pulmonary fibrosis. Pulmonary fibrosis is a chronic lung disease characterized by excessive deposition of the extracellular matrix and remodeling of the lung tissue structure. Clarifying the pathogenesis of pneumoconiosis plays an important guiding role in its treatment. The occurrence and development of pneumoconiosis are accompanied by epigenetic factors (e.g., DNA methylation and noncoding RNA) changes, which in turn can promote or inhibit the process of pneumoconiosis. Here, we summarize epigenetic changes and functions in the several kinds of evidence classification (epidemiological investigation, in vivo, and in vitro experiments) and main types of cells (macrophages, fibroblasts, and alveolar epithelial cells) to provide some clues for finding specific therapeutic targets for pneumoconiosis and even for pulmonary fibrosis.

The Functional Role of Long Non-Coding RNAs in Melanoma

Melanoma is the most lethal skin cancer, with increasing incidence worldwide. The molecular events that drive melanoma development and progression have been extensively studied, resulting in significant improvements in diagnostics and therapeutic approaches. However, a high drug resistance to targeted therapies and adverse effects of immunotherapies are still a major challenge in melanoma treatment. Therefore, the elucidation of molecular mechanisms of melanomagenesis and cancer response to treatment is of great importance. Recently, many studies have revealed the close association of long noncoding RNAs (lncRNAs) with the development of many cancers, including melanoma. These RNA molecules are able to regulate a plethora of crucial cellular processes including proliferation, differentiation, migration, invasion and apoptosis through diverse mechanisms, and even slight dysregulation of their expression may lead to tumorigenesis. lncRNAs are able to bind to protein complexes, DNA and RNAs, affecting their stability, activity, and localization. They can also regulate gene expression in the nucleus. Several functions of lncRNAs are context-dependent. This review summarizes current knowledge regarding the involvement of lncRNAs in melanoma. Their possible role as prognostic markers of melanoma response to treatment and in resistance to therapy is also discussed.

Non-coding RNAs in melanoma: Biological functions and potential clinical applications

Malignant melanoma (MM) is a malignant tumor that originates from melanocytes and has a high mortality rate. Therefore, early diagnosis and treatment are very important for survival. So far, the exact molecular mechanism leading to the occurrence of melanoma, especially the molecular metastatic mechanism, remains largely unknown. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNA (circRNAs), have been investigated and found to play vital roles in regulating tumor occurrence and development, including melanoma. In this review, we summarize the progress of recent research on the effects of ncRNAs on melanoma and attempt to elucidate the role of ncRNAs as molecular markers or potential targets that will provide promising application perspectives on melanoma.

OIP5-AS1 contributes to the development in endometrial carcinoma cells by targeting miR-152-3p to up-regulate SLC7A5

Background

Endometrial carcinoma (EC) is one common gynecological tumor, threatening physical and psychological health of females. Huge amount of essays indicated that long non-coding RNAs (lncRNAs) were widely reported to serve as a crucial regulator in the biological movements among multiple carcinomas, including EC.

Methods

RT-qPCR was implemented to detect the expression of target genes. Loss/gain-of-function experiments certified the impacts of OIP5-AS1 and miR-152-3p on EC cell progression.

Results

Data of this research suggested that powerful expression of OIP5-AS1 was discovered in EC cell lines. Loss/gain-of-function assays inferred that OIP5-AS1 promoted proliferative, migratory and invasive abilities, and Epithelial-Mesenchymal Transition (EMT). In addition, we identified miR-152-3p expression was negatively modulated by OIP5-AS1. OIP5-AS1 accelerated the development of EC cells via downregulating miR-152-3p expression. SLC7A5 was selected out as a downstream target of miR-152-3p. The competing relationship between OIP5-AS1 and SLC7A5 was corroborated by luciferase reporter assay. Eventually, the results of rescue assays indicated that SLC7A5 overexpression could restore the impacts of OIP5-AS1 ablation on the progression of EC cells.

Conclusion

Our research confirmed that OIP5-AS1 propeled the development of EC cells through targeting miR-152-3p/SLC7A5. OIP5-AS1 could be utilized as a target for EC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02061-0.

PI3K Inhibitors in Cancer: Clinical Implications and Adverse Effects

The phospatidylinositol-3 kinase (PI3K) pathway is a crucial intracellular signaling pathway which is mutated or amplified in a wide variety of cancers including breast, gastric, ovarian, colorectal, prostate, glioblastoma and endometrial cancers. PI3K signaling plays an important role in cancer cell survival, angiogenesis and metastasis, making it a promising therapeutic target. There are several ongoing and completed clinical trials involving PI3K inhibitors (pan, isoform-specific and dual PI3K/mTOR) with the goal to find efficient PI3K inhibitors that could overcome resistance to current therapies. This review focuses on the current landscape of various PI3K inhibitors either as monotherapy or in combination therapies and the treatment outcomes involved in various phases of clinical trials in different cancer types. There is a discussion of the drug-related toxicities, challenges associated with these PI3K inhibitors and the adverse events leading to treatment failure. In addition, novel PI3K drugs that have potential to be translated in the clinic are highlighted.

The HOTAIR lncRNA: A remarkable oncogenic promoter in human cancer metastasis

Long non-coding RNA (lncRNA) is a new type of non-coding RNA that has an important regulatory influence on several human diseases, including cancer metastasis. HOX antisense intergenic RNA (HOTAIR), a newly discovered lncRNA, has an important effect on tumour proliferation, migration and metastasis. HOTAIR regulates cell proliferation, changes gene expression, and promotes tumour cell invasion and migration. However, its molecular mechanism of action remains unknown. The present review summarizes the molecular mechanism and role of HOTAIR in tumour invasion and metastasis, discusses the association between HOTAIR and tumour metastasis through different pathways, such as the transforming growth factor β, Wnt/β-catenin, PI3K/AKT/MAPK and vascular endothelial growth factor pathways, emphasizes the function of HOTAIR in human malignant tumour metastasis and provides a foundation for its application in the diagnosis, prognosis and medical treatment of various tumours.

Comprehensive Review on the Clinical Relevance of Long Non-Coding RNAs in Cutaneous Melanoma

Cutaneous melanoma is considered a rare tumor, although it is one of the most common cancers in young adults and its incidence has risen in the last decades. Targeted therapy, with BRAF and MEK inhibitors, and immunotherapy revolutionized the treatment of metastatic melanoma but there is still a considerable percentage of patients with primary or acquired resistance to these therapies. Recently, oncology researchers directed their attention at the role of long non-coding RNAs (lncRNAs) in different types of cancers, including melanoma. lncRNAs are RNA transcripts, initially considered "junk sequences", that have been proven to have a crucial role in the fine regulation of physiological and pathological processes of different tissues. Furthermore, they are more expressed in tumors than protein-coding genes, constituting perfect candidates either as biomarkers (diagnostic, prognostic, predictive) or as therapeutic targets. In this work, we reviewed all the literature available for lncRNA in melanoma, elucidating all the potential roles in this tumor.

The emerging role of non-coding RNAs in the regulation of PI3K/AKT pathway in the carcinogenesis process

The PI3K/AKT pathway is an intracellular signaling pathway with an indispensable impact on cell cycle control. This pathway is functionally related with cell proliferation, cell survival, metabolism, and quiescence. The crucial role of this pathway in the development of cancer has offered this pathway as a target of novel anti-cancer treatments. Recent researches have demonstrated the role of microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) in controlling the PI3K/AKT pathway. Some miRNAs such as miR-155-5p, miR-328-3p, miR-125b-5p, miR-126, miR-331-3p and miR-16 inactivate this pathway, while miR-182, miR-106a, miR-193, miR-214, miR-106b, miR-93, miR-21 and miR-103/107 enhance activity of this pathway. Expression levels of PI3K/AKT-associated miRNAs could be used to envisage the survival of cancer patients. Numerous lncRNAs such as GAS5, FER1L4, LINC00628, PICART1, LOC101928316, ADAMTS9-AS2, SLC25A5-AS1, MEG3, AB073614 and SNHG6 interplay with this pathway. Identification of the impact of miRNAs and lncRNAs in the control of the activity of PI3K/AKT pathway would enhance the efficacy of targeted therapies against this pathway. Moreover, each of the mentioned miRNAs and lncRNAs could be used as a putative therapeutic candidate for the interfering with the carcinogenesis. In the current study, we review the role of miRNAs and lncRNAs in controlling the PI3K/AKT pathway and their contribution to carcinogenesis.

The role of HOTAIR/miR-152-3p/LIN28B in regulating the progression of endometrial squamous carcinoma

INTRODUCTION

There is growing evidence that long non-coding RNAs (lncRNAs) are correlated with malignancy in the modulation of tumor progression. This study aims to investigate the effect of homeobox protein (HOX) transcript antisense RNA (HOTAIR) on the migration and invasion of ESC.

MATERIAL AND METHODS

Starbase was used to identify miRNAs with complementary base pairing with HOTAIR. RNA pull-down and qRT-PCR were employed to investigate the effect of HOTAIR on miR-152-3p. In vitro cell migration and invasion assays were performed to assess the effects of HOTAIR and miR-152-3p on ESC. Computational software, TargetScan, was then used to identify the potential target of miR-152-3p, and their relationship was verified by immunoblotting analysis, qRT-PCR and luciferase reporter assay.

RESULTS

Starbase predicted a potential miR-152-3p binding site in HOTAIR, which was validated by RNA pull-down assay. HOTAIR was negatively correlated with miR-152-3p in ESC. Moreover, HOTAIR promoted migration and invasion of ESC. The oncogenic activity of HOTAIR was partly through its negative regulation of miR-152-3p. LIN28B was identified to be a direct target of miR-152-3p. A negative correlation between LIN28B and miR-152-3p was observed in ESC. In addition, overexpression of miR-152-3p suppressed the progression of ESC by directly targeting and regulating LIN28B.

CONCLUSIONS

Our results reveal that HOTAIR may be a driver of ESC through inhibiting miR-152-3p, a tumor suppressor, suggesting that miR-152-3p may be a potential target for advanced ESC therapeutic treatment.

LncRNA HOTAIR Promotes Proliferation of Malignant Melanoma Cells through NF-ϰB Pathway

Background:

To study the effects of long non-coding ribonucleic acid (lncRNA) HOX transcript antisense intergenic RNA (HOTAIR) on the proliferation and apoptosis of malignant melanoma cells, and to explore its specific regulatory mechanism through the nuclear factor-kappa B (NF-ϰB) signaling pathway.

Methods:

LncRNA HOTAIR small-interfering RNAs (siRNAs) were designed and synthesized, and the effects of si-HOTAIR transfection on the proliferation and apoptosis of malignant melanoma cells were detected via cell counting kit-8 (CCK-8) assay, 4’,6-diamidino-2-phenylindole (DAPI) staining assay and flow cytometry, respectively. The gene expressions were determined using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), the changes in NF-ϰB pathway-related proteins and apoptosis-associated proteins after interference in lncRNA HOTAIR were detected via Western blotting, and the level of NF-ϰB in each group was determined via ELISA.

Results:

The results of CCK-8 assay revealed that the cell proliferation rate significantly declined gradually in si-HOTAIR group compared with that in si-NC group and control group (P<0.05). The results of Western blotting and ELISA showed that the activity of NF-ϰB in si-HOTAIR group was weakened (P<0.05), suggesting that down-regulation of HOTAIR can suppress the activity of NF-ϰB. Compared with si-NC group and control group, si-HOTAIR group had remarkably increased gene and protein expressions of pro-apoptotic Bax, and remarkably decreased gene and protein expressions of anti-apoptotic Bcl-2 (P<0.05), demonstrating that down-regulation of HOTAIR can promote apoptosis.

Conclusion:

Down-regulation of lncRNA HOTAIR can inhibit the proliferation and promote the apoptosis of malignant melanoma cells and suppress the NF-ϰB pathway.

The critical roles of lncRNAs in the pathogenesis of melanoma

Long non-coding RNAs (lncRNAs) embrace a huge fraction of human transcripts and participate in the pathogenesis of human disorders especially malignant conditions. Malignant melanoma, as the most fatal type of cutaneous malignnacies, is associated with dysregulation of several lncRNAs including PVT1, H19, MALAT1, and CCAT1. Moreover, a portion of lncRNAs are exclusively expressed in melanoma cell lines. Expression levels of several lncRNAs are associated with TNM stage, tumor size and progression of melanoma. Thus, these lncRNAs are regarded as biomarkers for this malignancy. Peripheral transcript levels of a number of lncRNAs, such as PVT1, SNHG5 and SPRY4-IT1, could distinguish melanoma patients from unaffected persons with appropriate sensitivity and specificity values. Moreover, expression levels of numerous lncRNAs in tissue biopsies could differentiate malignant samples from benign samples. Based on the results of both cell line and in vivo studies, lncRNAs regulate critical pathways in the carcinogenesis of melanoma, such as the PI3K/Akt and NF-κB signaling pathways, and are involved in the modulation of response to chemotherapeutic agents. Here we review the existing information on the role of lncRNAs in malignant melanoma.

miR-152-3p Affects the Progression of Colon Cancer via the KLF4/IFITM3 Axis

OBJECTIVE

The purpose of this study was to investigate the relationship between miR-152-3p and the KLF4/IFITM3 axis, thereby revealing the mechanism underlying colon cancer occurrence and development, consequently providing a promising target for colon cancer treatment.

METHODS

Bioinformatics methods were implemented to analyze the differential expression of miRNAs and mRNAs in colon cancer, confirm the target miRNA, and predict the downstream targeted mRNAs. qRT-PCR and Western blot were performed to detect the expression of miR-152-3p, KLF4, and IFITM3. CCK-8 and colony formation assays were conducted for the assessment of cell proliferation, and flow cytometry was carried out for the detection of cell apoptosis. Finally, dual-luciferase reporter gene assay was employed to verify the targeting relationship between miR-152-3p and KLF4.

RESULTS

miR-152-3p was highly expressed in colon cancer cells, whereas KLF4 was poorly expressed. Dual-luciferase assay verified that miR-152-3p targeted to bind to KLF4 and suppressed its expression. Moreover, silencing miR-152-3p or overexpressing KLF4 was found to downregulate IFITM3, thereby inhibiting cell proliferation and potentiating cell apoptosis. In rescue experiments, we found that miR-152-3p deficiency decreased the expression of IFITM3 and weakened cancer cell proliferation, and such effects were restored when miR-152-3p and KLF4 were silenced simultaneously.

CONCLUSION

In sum, we discovered that miR-152-3p can affect the pathogenesis of colon cancer via the KLF4/IFITM3 axis.

Avasimibe inhibits the proliferation, migration and invasion of glioma cells by suppressing linc00339

Glioma is one of the most destructive human tumours. Although standard treatment has improved the prognosis for glioma patients, the survival of glioma patients is still unsatisfactory. Avasimibe, an effective inhibitor of cholesterol acyltransferase 1 (ACAT1), has shown anti-tumour efficacy in many kinds of tumours. However, its role and related mechanism in glioma has not been fully elucidated. In the present study, we show that avasimibe effectively inhibits the proliferation, migration and invasion of glioma cell lines. Through LncRNA microarrays, we found that linc00339 levels were closely related to the anti-tumour effect of avasimibe. With the help of a series of functional assays, we show that avasimibe inhibits the proliferation, migration and invasion of glioma cell lines by suppressing linc00339 in vitro and in vivo. Our findings may provide a new approach for glioma therapy.

lncRNA HOTAIR overexpression induced downregulation of c-Met signaling promotes hybrid epithelial/mesenchymal phenotype in hepatocellular carcinoma cells

Background

Epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) are both reversible processes, and regulation of phenotypical transition is very important for progression of several cancers including hepatocellular carcinoma (HCC). Recently, it is defined that cancer cells can attain a hybrid epithelial/mesenchymal (hybrid E/M) phenotype. Cells with hybrid E/M phenotype comprise mixed epithelial and mesenchymal properties, they can be more resistant to therapeutics and also more capable of initiating metastatic lesions. However, the mechanisms regulating hybrid E/M in HCC are not well described yet. In this study, we investigated the role of the potential crosstalk between lncRNA HOTAIR and c-Met receptor tyrosine kinase, which are two essential regulators of EMT and MET, in acquiring of hybrid E/M phenotype in HCC.

Methods

Expression of c-Met and lncRNA HOTAIR were defined in HCC cell lines and patient tissues through HCC progression. lncRNA HOTAIR was overexpressed in SNU-449 cells and its effects on c-Met signaling were analyzed. c-Met was overexpressed in SNU-398 cells and its effect on HOTAIR expression was analyzed. Biological significance of HOTAIR/c-Met interplay was defined in means of adhesion, proliferation, motility behavior, invasion, spheroid formation and metastatic ability. Effect of ectopic lncRNA HOTAIR expression on phenotype was defined with investigation of molecular epithelial and mesenchymal traits.

Results

In vitro and in vivo experiments verified the pivotal role of lncRNA HOTAIR in acquisition of hybrid E/M phenotype through modulating expression and activation of c-Met and its membrane co-localizing partner Caveolin-1, and membrane organization to cope with the rate limiting steps of metastasis such as survival in adhesion independent microenvironment, escaping from anoikis and resisting to fluidic shear stress (FSS) in HCC.

Conclusions

Our work provides the first evidence suggesting a role for lncRNA HOTAIR in the modulation of c-Met to promote hybrid E/M phenotype. The balance between lncRNA HOTAIR and c-Met might be critical for cell fate decision and metastatic potential of HCC cells.

Long non-coding RNA LINC00520 promotes the proliferation and metastasis of malignant melanoma by inducing the miR-125b-5p/EIF5A2 axis

BACKGROUND

Long intergenic non-protein coding RNA 520 (LINC00520), a novel identified lncRNA, has been shown to modulate the malignant phenotype of tumor cells in some malignant tumors. However, the exact role and molecular mechanism of LINC00520 in malignant melanoma has not been studied.

METHODS

The expression of LINC00520 in melanoma tissues were detected by using RNA-seq analysis and qRT-PCR. Melanoma cases from the public databases (The Cancer Genome Atlas (TCGA), GEO#GSE15605, GEO#GSE34460 and GEO#GSE24996) were included in this study. CCK-8 assay, EdU assay, transwell and scratch wound assay were used to explore the role of LINC00520 in melanoma cells. Luciferase reporter assays, MS2-RIP, RNA pull-down and RNA-ChIP assay were used to demonstrate the molecular biological mechanism of LINC00520 in melanoma.

RESULTS

We found that LICN00520 was found to be overexpressed in melanoma tissue. High expression of LICN00520 is a risk factor for the prognosis of melanoma patients. LINC00520 promotes the proliferation, invasion and migration of melanoma cells. LICN00520 exerted its oncogenic role by competitive binding miR-125b-5p to promote Eukaryotic initiation factor 5A2 (EIF5A2) expression. We also showed that LICN00520 promotes the growth and metastasis of melanoma in vivo through regulating miR-125b-5p/EIF5A2 axis.

CONCLUSIONS

All results elucidated the role and molecular mechanism of LINC00520 in the malignant development of melanoma. LINC00520, a new oncogene in melanoma, maybe serve as a survival biomarkers or therapeutic target for melanoma patients.

CCAT2 contributes to hepatocellular carcinoma progression via inhibiting miR-145 maturation to induce MDM2 expression

Long noncoding RNA colon cancer-associated transcript 2 (CCAT2) has been recently found to function as an oncogene in hepatocellular carcinoma (HCC). However, the mechanisms of CCAT2 in HCC development remain to be further explored. In the present study, we found that CCAT2 was abnormally upregulated in HCC cells and tissue specimens, exhibiting an inverse correlation with microRNA (miR)-145 expression. Mechanistic investigation showed that CCAT2 selectively blocked miR-145 processing, leading to decreased mature miR-145 presence. Both the in vitro and in vivo effects of CCAT2 knockdown on the proliferation and metastasis of HCC cells were reversed by miR-145 inhibitor, indicating that miR-145 modulation accounts for CCAT2-meditated HCC progression. Furthermore, miR-145 mimic dramatically suppressed HCC cells' proliferation and metastasis, revealing a tumor suppressor role of miR-145 in HCC. Mechanistically, MDM2 was predicted to be a potential target of miR-145. The luciferase and western blot assay demonstrated that miR-145 mimic largely inhibited MDM2 3'-untranslated region luciferase activity and MDM2 expression, followed by the upregulation of p53/p21 expression. Finally, the coexpression of MDM2 in miR-145 mimic-transfected HCC cells was able to largely compromise the inhibitory effects of miR-145 mimic on HCC cells' proliferation and metastasis in vitro and tumor formation in a xenograft model, confirming MDM2 is the critical mediator of miR-145 in HCC. In summary, our findings indicated that CCAT2 selectively blocks the miR-145 maturation process and plays an oncogene in HCC. Furthermore, a novel CCAT2/miR-145/MDM2 axis was revealed in HCC development and might provide a new target in the molecular treatment of HCC.

Curcumol inhibits the proliferation and metastasis of melanoma via the miR-152-3p/PI3K/AKT and ERK/NF-κB signaling pathways

Melanoma is the most aggressive and treatment-resistant form of skin cancer. Curcumol is a Chinese medicinal herb traditionally used as a cancer remedy. However, the molecular mechanisms underlying the anticancer activity of curcumol in melanoma remains largely unknown. In the present study, we observed that Curcumol decreased mouse melanoma B16 cell proliferation and migration. The xenograft tumor assay showed that curcumol reduced melanoma volume and lung metastasis. Curcumol upregulated the expression of E-cadherin and downregulated the expression of N-cadherin, MMP2 and MMP9 in mouse melanoma B16 cell. Western blot analysis revealed that curcumol reduced the translocation of p65 to the nucleus and decreased p-ERK. Furthermore, curcumol attenuated c-MET, P13K and p-AKT protein expression and upregulated miR-152-3p gene expression. The dual-luciferase reporter assay indicated that c-MET was a target gene of miR-152-3p. Reduced expression of miR-152-3p partially attenuated the effect of curcumol on mouse melanoma B16 cell proliferation and migration. The decrease in c-MET, P13K and p-AKT protein expression following curcumol treatment in mouse melanoma B16 cells was notably attenuated by the miR-152-3p inhibitor. Taken together, our findings suggested that curcumol attenuated melanoma progression and concomitantly suppressed ERK/NF-κB signaling and promoted miR-152-3p expression to inactivate the c-MET/PI3K/AKT signaling pathway.

Interactions Among Regulatory Non-coding RNAs Involved in Cardiovascular Diseases

Non-coding RNAs (ncRNAs) are important regulatory players in human cells that have been shown to modulate different cellular processes and biological functions through controlling gene expression, being also involved in pathological conditions such as cardiovascular diseases. Among them, long non-coding RNAs (lncRNAs) and circular (circRNAs) could act as competing endogenous RNAs (ceRNAs) sequestering other ncRNAs. This entangled network of interactions has been reported to trigger the decay of the targeted ncRNAs having important roles in gene regulation. Growing evidences have been demonstrated that the regulatory mechanism underlying the crosstalk between different ncRNA species, namely lncRNAs, circRNAs and miRNAs has also an important role in the pathophysiological processes of cardiovascular diseases. In this chapter, the main regulatory relationship among lncRNAs, circRNAs and miRNAs were summarized and their role in the control and development of cardiovascular diseases was highlighted.

The MSC-Derived Exosomal lncRNA H19 Promotes Wound Healing in Diabetic Foot Ulcers by Upregulating PTEN via MicroRNA-152-3p

Mesenchymal stem cells (MSCs) have been reported to hold promise to accelerate the wound-healing process in diabetic foot ulcer (DFU) due to the multilineage differentiation potential. Hence, this study intended to explore the wound healing role of MSC-derived exosomes containing long noncoding RNA (lncRNA) H19 in DFU. lncRNA H19 was predicated to bind to microRNA-152-3p (miR-152-3p), which targeted phosphatase and tensin homolog (PTEN) deleted on chromosome ten. Fibroblasts in DFU samples exhibited highly expressed miR-152-3p and poorly expressed lncRNA H19 and PTEN, along with an activated phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (Akt1) signaling pathway. The fibroblasts were cocultured with lncRNA H19-transfected MSCs and MSC-derived exosomes to assess the effect of the lncRNA H19/miR-152-3p/PTEN axis on the biological activities and inflammation in fibroblasts. Mouse models of DFU were developed by streptozotocin, which was injected with MSC-derived exosomes overexpressing lncRNA H19. lncRNA H19 in MSCs was transferred through exosomes to fibroblasts, the mechanism of which improved wound healing in DFU, corresponded to promoted fibroblast proliferation and migration, as well as suppressed apoptosis and inflammation. Wound healing in mice with DFU was facilitated following the injection of MSC-derived exosomes overexpressing lncRNA H19. Taken together, MSC-derived exosomal lncRNA H19 prevented the apoptosis and inflammation of fibroblasts by impairing miR-152-3p-mediated PTEN inhibition, leading to the stimulated wound-healing process in DFU.

Long non-coding RNA ZEB1-AS1 promotes colon adenocarcinoma malignant progression via miR-455-3p/PAK2 axis

Objective

The long non‐coding RNA zinc finger E‐box‐binding homeobox 1 antisense 1 (ZEB1‐AS1) acts as an oncogenic regulator in many human tumours. In the present study, we identify the role and potential molecular biological mechanisms of ZEB1‐AS1 in colon adenocarcinoma (COAD).

Methods

QRT‐PCR was used to detect the expression of ZEB1‐AS1, miR‐455‐3p and p21‐activated kinases 2 (PAK2) in COAD tissues. CCK8 assay, EdU assay, transwell assay and scratch wound assay were used to explore the biological function of ZEB1‐AS1 in COAD cells. Bioinformatics, luciferase reporter assays and an RNA pull‐down assay were used to demonstrate the mechanism of ZEB1‐AS1. We further explore the role of ZEB1‐AS1 in vivo though xenograft tumour assay.

Results

We found that ZEB1‐AS1 expression was significantly up‐regulated in COAD tissues, and high ZEB1‐AS1 level was correlated with the poor prognosis of COAD patients. MiR‐455‐3p plays an anti‐cancer role in COAD by targeting PAK2. We confirmed that ZEB1‐AS1 promotes PAK2 expression by sponging miR‐455‐3p, thus facilitating COAD cell growth and metastasis.

Conclusions

To sum up, this result illustrates the novel molecular mechanism of ZEB1‐AS1 in COAD and provides a new target for the diagnosis and treatment of COAD patients.

The long coding RNA AFAP1-AS1 promotes tumor cell growth and invasion in pancreatic cancer through upregulating the IGF1R oncogene via sequestration of miR-133a

Long non-coding RNAs (lncRNAs) have been shown to play a significant role in the progression of many cancers, including pancreatic cancer (PC). However, the biological function and regulatory mechanisms of lncRNAs in PC remains largely unclear. The aim of this study was to identify and evaluate the potential functions of lncRNAs in PC and reveal the underlying mechanisms of their effects. Screening of published microarray data (GEO accession Nos. GSE16515 and GSE32688), revealed lncRNA AFAP1-AS1 to be one of the most upregulated lncRNAs in PC tissues. High expression of AFAP1-AS1 was correlated with advanced stages, tumor size and lymph node metastasis, as well as with poorer overall survival in patients with PC. Functionally, knockdown of AFAP1-AS1 by transfection with siRNA inhibited the proliferative and invasive capacities of PaCa-2 and SW1990 PC cells, promoted apoptosis of PC cells in vitro, and impaired in-vivo tumorigenicity. In particular, it was hypothesized that AFAP1-AS1 may act as a competitive endogenous RNA (ceRNA), effectively becoming a sink for miR-133a whose expression was found to be downregulated in PC tissues and cell lines, and which was negatively correlated with the expression of AFAP1-AS1. We also found that the IGF1R oncogene which is an important regulator of MEK/ERK signaling pathway, was positively regulated by AFAP1-AS1 through ameliorating miR-133a-mediated IGF1R repression in PC tissues. Moreover, we demonstrated that knockdown of IGF1R by transfection with si-IGF1R suppressed cell proliferation, invasion and migration of PaCa-2 and SW1990 PC cells, suggesting that IGF1R may function as an oncogene in PC cells. Further investigations revealed that miR-133a reversed the biological effects of AFAP1-AS1 on PC cells. Collectively, the findings provide new evidence that AFAP1-AS1 could regulate the progression of pancreatic cancer by acting as a ceRNA, and suggest it has potential for use as both a biomarker for the early detection PC and for the development of individualized therapies for PC.

Inferring disease and pathway associations of long non-coding RNAs using heterogeneous information network model

Recent findings from biological experiments demonstrate that long non-coding RNAs (lncRNAs) are actively involved in critical cellular processes and are associated with innumerable diseases. Computational prediction of lncRNA-disease association draws tremendous research attention nowadays. This paper proposes a machine learning model that predicts lncRNA-disease associations using Heterogeneous Information Network (HIN) of lncRNAs and diseases. A Support Vector Machine classifier is developed using the feature set extracted from a meta-path-based parameter, Association Index derived from the HIN. Performance of the model is validated using standard statistical metrics and it generated an AUC value of 0.87, which is better than the existing methods in the literature. Results are further validated using the recent literature and many of the predicted lncRNA-disease associations are identified as actually existing. This paper also proposes an HIN-based methodology to associate lncRNAs with pathways in which they may have biological influence. A case study on the pathway associations of four well-known lncRNAs (HOTAIR, TUG1, NEAT1, and MALAT1) has been conducted. It has been observed that many times the same lncRNA is associated with more than one biologically related pathways. Further exploration is needed to substantiate whether such lncRNAs have any role in determining the pathway interplay. The script and sample data for the model construction is freely available at http://bdbl.nitc.ac.in/LncDisPath/index.html.

Long non-coding RNAs in cutaneous biology and proliferative skin diseases: Advances and perspectives

Advances in transcriptome sequencing have revealed that the genome fraction largely encodes for thousands of non‐coding RNAs. Long non‐coding RNAs (lncRNAs), which are a class of non–protein‐coding RNAs longer than approximately 200 nucleotides in length, are emerging as key epigenetic regulators of gene expression recently. Intensive studies have characterized their crucial roles in cutaneous biology and diseases. In this review, we address the promotive or suppressive effects of lncRNAs on cutaneous physiological processes. Then, we focus on the pathogenic role of dysfunctional lncRNAs in a variety of proliferative skin diseases. These evidences suggest that lncRNAs have indispensable roles in the processes of skin biology. Additionally, lncRNAs might be promising biomarkers and therapeutic targets for cutaneous disorders.

Comprehensive Analysis of a Competing Endogenous RNA Network Identifies Seven-lncRNA Signature as a Prognostic Biomarker for Melanoma

Long non-coding RNAs (LncRNAs) can act as competing endogenous RNA (ceRNA) involving in tumor initiation and progression. Nevertheless, the prognostic roles of lncRNAs in lncRNA-related ceRNA network of melanoma remain elusive. In this study, RNA sequence profiles were downloaded from The Cancer Genome Atlas (TCGA) database, and there were 2020 differentially expressed messenger RNAs (DEmRNAs), 438 differentially expressed lncRNAs (DElncRNAs) and 65 differentially expressed microRNAs (DEmiRNAs) between primary and metastasis melanoma patients. A ceRNA regulatory network was constructed based on the DElncRNAs-DEmiRNAs and DEmiRNAs-DEmRNAs interactions, which contained 39 lncRNAs, 10 miRNAs, and 16 mRNAs. Furthermore, univariate and multivariate Cox regression analysis were carried out to establish a 7-lncRNA prognostic signature. Subsequently, the area under the curve (AUC) value of the receiver operating characteristic (ROC) curve and the Kaplan-Meier risk survival analysis revealed the significant performance of this signature. Finally, pathway enrichment analyses implied that lncRNA MIR205HG and MIAT were associated with multiple cancer-related pathways, especially epidermis development and immune response. The current study provides novel insights into the lncRNA-related ceRNA network and the potential of lncRNAs to be candidate prognostic biomarkers and therapeutic targets in melanoma.

Long non-coding RNA LINC00174 promotes glycolysis and tumor progression by regulating miR-152-3p/SLC2A1 axis in glioma

BACKGROUND

Long non-coding RNA plays a crucial role in the occurrence and progression of glioma. We aimed to explore the function of LINC00174 in cell proliferation, apoptosis, migration, invasion and glycolysis of glioma cells, and investigate the molecular mechanism involved.

METHODS

LINC00174 expression in glioma tissues and peritumoral brain edema (PTBE) tissues was examined by RT-qPCR and in situ hybridization. The CCK-8, TUNEL, wound healing, transwell, and ELISA assays were performed to identify the effects of LINC00174 knockdown on cell viability, apoptosis, migration, invasion, and glycolysis, respectively. RNA immunoprecipitation, dual-luciferase reporter, RNA pull down, and western blot assays were performed to explore the molecular mechanisms of LINC00174 in glioma cells. A nude mouse xenograft model was used to investigate the role of LINC00174 in xenograft glioma growth.

RESULTS

LINC00174 was overexpressed in glioma tissues and cell lines. LINC00174 knockdown inhibited cell proliferation, migration, invasion and glycolysis of glioma cells, and LINC00174 exerted a tumorigenesis role. LINC00174 could interact with miR-152-3p/SLC2A1 axes. The miR-152-3p inhibitor or the SLC2A1 overexpression could rescue the anti-tumor effect of LINC00174 knockdown on glioma cells. Moreover, downregulation of LINC00174 also inhibited tumor volume and delayed the tumor growth in vivo.

CONCLUSION

LINC00174 accelerated carcinogenesis of glioma via sponging miR-1523-3p and increasing the SLC2A1 expression, which could be considered as a molecular target for glioma diagnosis and therapy.

Linc00961 inhibits the proliferation and invasion of skin melanoma by targeting the miR‑367/PTEN axis

Long intergenic noncoding RNA 00961 (Linc00961) has been identified as a tumor suppressor in various types of cancer. However, the critical roles of Linc00961 in the carcinogenesis and progression of skin melanoma (SM) are yet to be fully elucidated. The present study revealed via reverse transcription‑quantitative PCR analysis that Linc00961 was downregulated in the tissues of patients with SM compared with benign nevi, and in A375, A2058 and SK‑MEL‑28 cell lines compared with human melanocytes. Furthermore, overexpression of Linc00961 inhibited cell proliferation, and promoted the apoptosis of A375 and SK‑MEL‑28 cells in vitro and in vivo, as determined by Cell Counting Kit‑8 and flow cytometry assays, and tumor xenograft studies, respectively. Overexpression of Linc00961 also led to an attenuation of the migration and invasive capabilities of A375 and SK‑MEL‑28 cells, measured using Transwell assays. Functionally, it was demonstrated that Linc00961 acted as a competing endogenous RNA (ceRNA) by competitively sponging microRNA‑367 (miR‑367) in A375 and SK‑MEL‑28 cells; restoration of miR‑367 rescued the inhibitory effects of Linc00961 on A375 and SK‑MEL‑28 cells. Finally, it was observed that phosphate and tension homology deleted on chromosome 10 (PTEN), an established target of miR‑367 in A375 and SK‑MEL‑28 cells, was positively regulated by Linc00961, and its inhibition reversed the inhibitory effects of Linc00961 on the proliferation and invasion of A375 and SK‑MEL‑28 cells. Collectively, the present study revealed that Linc00961 was downregulated in SM, and furthermore, Linc00961 was identified as a ceRNA that inhibits the proliferation and invasion of A375 and SK‑MEL‑28 cells by modulating the miR‑367/PTEN axis.

Role and Therapeutic Targeting of the PI3K/Akt/mTOR Signaling Pathway in Skin Cancer: A Review of Current Status and Future Trends on Natural and Synthetic Agents Therapy

The mammalian or mechanistic target of rapamycin (mTOR) and associated phosphatidyl-inositiol 3-kinase (PI3K)/protein kinase B (Akt) pathways regulate cell growth, differentiation, migration, and survival, as well as angiogenesis and metabolism. Dysregulation of these pathways is frequently associated with genetic/epigenetic alterations and predicts poor treatment outcomes in a variety of human cancers including cutaneous malignancies like melanoma and non-melanoma skin cancers. Recently, the enhanced understanding of the molecular and genetic basis of skin dysfunction in patients with skin cancers has provided a strong basis for the development of novel therapeutic strategies for these obdurate groups of skin cancers. This review summarizes recent advances in the roles of PI3K/Akt/mTOR and their targets in the development and progression of a broad spectrum of cutaneous cancers and discusses the current progress in preclinical and clinical studies for the development of PI3K/Akt/mTOR targeted therapies with nutraceuticals and synthetic small molecule inhibitors.

HOTAIR as a Prognostic Predictor for Diverse Human Cancers: A Meta- and Bioinformatics Analysis

Several studies suggest that upregulated expression of the long non-coding RNA HOX transcript antisense RNA (HOTAIR) is a negative predictive biomarker for numerous cancers. Herein, we performed a meta-analysis to further investigate the prognostic value of HOTAIR expression in diverse human cancers. To this end, a systematic literature review was conducted in order to select scientific studies relevant to the association between HOTAIR expression and clinical outcomes, including overall survival (OS), recurrence-free survival (RFS)/disease-free survival (DFS), and progression-free survival (PFS)/metastasis-free survival (MFS) of cancer patients. Collectively, 53 eligible studies including a total of 4873 patients were enrolled in the current meta-analysis. Pooled hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were calculated to assess the relationship between HOTAIR and cancer patients’ survival. Elevated HOTAIR expression was found to be significantly associated with OS, RFS/DFS and PFS/MFS in diverse types of cancers. These findings were also corroborated by the results of bioinformatics analysis on overall survival. Therefore, based on our findings, HOTAIR could serve as a potential biomarker for the prediction of cancer patient survival in many different types of human cancers.

Targeting PI3K in cancer: mechanisms and advances in clinical trials

Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling is one of the most important intracellular pathways, which can be considered as a master regulator for cancer. Enormous efforts have been dedicated to the development of drugs targeting PI3K signaling, many of which are currently employed in clinical trials evaluation, and it is becoming increasingly clear that PI3K inhibitors are effective in inhibiting tumor progression. PI3K inhibitors are subdivided into dual PI3K/mTOR inhibitors, pan-PI3K inhibitors and isoform-specific inhibitors. In this review, we performed a critical review to summarize the role of the PI3K pathway in tumor development, recent PI3K inhibitors development based on clinical trials, and the mechanisms of resistance to PI3K inhibition.

Tomato lncRNA23468 functions as a competing endogenous RNA to modulate NBS-LRR genes by decoying miR482b in the tomato-Phytophthora infestans interaction

Our previous studies indicated that tomato miR482b could negatively regulate the resistance of tomato to Phytophthora infestans and the expression of miR482b was decreased after inoculation with P. infestans. However, the mechanism by which the accumulation of miR482b is suppressed remains unclear. In this study, we wrote a program to identify 89 long noncoding RNA (lncRNA)-originated endogenous target mimics (eTMs) for 46 miRNAs from our RNA-Seq data. Three tomato lncRNAs, lncRNA23468, lncRNA01308 and lncRNA13262, contained conserved eTM sites for miR482b. When lncRNA23468 was overexpressed in tomato, miR482b expression was significantly decreased, and the expression of the target genes, NBS-LRRs, was significantly increased, resulting in enhanced resistance to P. infestans. Silencing lncRNA23468 in tomato led to the increased accumulation of miR482b and decreased accumulation of NBS-LRRs, as well as reduced resistance to P. infestans. In addition, the accumulation of both miR482b and NBS-LRRs was not significantly changed in tomato plants that overexpressed lncRNA23468 with a mutated eTM site. Based on the VIGS system, a target gene of miR482b, Solyc02g036270.2, was silenced. The disease symptoms of the VIGS-Solyc02g036270.2 tomato plants were in accordance with those of tomato plants in which lncRNA23468 was silenced after inoculation with P. infestans. More severe disease symptoms were found in the modified plants than in the control plants. Our results demonstrate that lncRNAs functioning as eTMs may modulate the effects of miRNAs in tomato and provide insight into how the lncRNA23468-miR482b-NBS-LRR module regulates tomato resistance to P. infestans.

Long noncoding RNA GACAT3 promotes glioma progression by sponging miR-135a

The long noncoding RNA (lncRNA) gastric cancer associated transcript 3 (GACAT3) has been reported to play important roles in human tumorigenesis. However, its expression pattern, functions, and underlying mechanism in glioma remain unclear. In the present study, we showed that GACAT3 is upregulated in glioma tissues and cell lines. Through online databases, luciferase reporter assays and RNA immunoprecipitation (RIP) assays, we determined that GACAT3 acts as a competing endogenous RNA (ceRNA) for microRNA (miR)-135a, which was downregulated and performed as a tumor inhibitor in glioma. Further, nicotinamide phosphoribosyl transferase (NAMPT) was confirmed as a target gene of miR-135a by a series of gain- and loss-of-function assays. Overall, the present study was the first to show that GACAT3 regulates the expression of NAMPT to promote glioma progression by sponging miR-135a. These findings provide a promising therapy strategy for glioma.

RNA interference of long noncoding RNA HOTAIR suppresses autophagy and promotes apoptosis and sensitivity to cisplatin in oral squamous cell carcinoma

BACKGROUND

Long noncoding RNA HOX transcript antisense RNA (lncRNA HOTAIR) is overexpressed in many types of human cancers and is correlated with clinical stage and lymph node metastasis in oral squamous cell carcinoma (OSCC). Autophagy, an important mechanism of self-protection, plays vital roles in adapting to hypoxia, tolerating external stimulation, and inducing chemotherapy resistance in OSCC cells. This study aims to investigate the effect of HOTAIR on autophagy, apoptosis, and invasion of OSCC cells.

METHODS

HOTAIR expression in OSCC cells was knocked down by small RNA interference. Transmission electron microscope, Western blot, and flow cytometry assay were used to detect the level of autophagy and apoptosis. OSCC cells were medicated with cisplatin, and median lethal dose (LD50) was performed to evaluate the effect on chemosensitivity of HOTAIR.

RESULTS

After HOTAIR silence, autophagy was inhibited with the downregulated expression of MAP1LC3B (microtubule-associated protein 1 light chain 3B), beclin1, and autophagy-related gene (ATG) 3 and ATG7. The expressions of mTOR increased. Proliferation, migration, and invasion of OSCC cells were suppressed. Furthermore, apoptosis rate was enhanced, and the sensitivity to cisplatin was promoted when compared with the negative control group.

CONCLUSION

HOTAIR acts as an oncogene in OSCC cells, and HOTAIR silence may be a potential therapeutic target for OSCC.