MiR-520b as a novel molecular target for suppressing stemness phenotype of head-neck cancer by inhibiting CD44

Panoramic view of key cross-talks underpinning the oral squamous cell carcinoma stemness - unearthing the future opportunities

The clinical management of oral cancer is often frequented with challenges that arise from relapse, recurrence, invasion and resistance towards the cornerstone chemo and radiation therapies. The recent conceptual advancement in oncology has substantiated the role of cancer stem cells (CSC) as a predominant player of these intricacies. CSC are a sub-group of tumor population with inherent adroitness to self-renew with high plasticity. During tumor evolution, the structural and functional reprogramming persuades the cancer cells to acquire stem-cell like properties, thus presenting them with higher survival abilities and treatment resistance. An appraisal on key features that govern the stemness is of prime importance to confront the current challenges encountered in oral cancer. The nurturing niche of CSC for maintaining its stemness characteristics is thought to be modulated by complex multi-layered components encompassing neoplastic cells, extracellular matrix, acellular components, circulatory vessels, various cascading signaling molecules and stromal cells. This review focuses on recapitulating both intrinsic and extrinsic mechanisms that impart the stemness. There are contemplating evidences that demonstrate the role of transcription factors (TF) in sustaining the neoplastic stem cell's pluripotency and plasticity alongside the miRNA in regulation of crucial genes involved in the transformation of normal oral mucosa to malignancy. This review illustrates the interplay between miRNA and various known TF of oral cancer such as c-Myc, SOX, STAT, NANOG and OCT in orchestrating the stemness and resistance features. Further, the cross-talks involved in tumor micro-environment inclusive of cytokines, macrophages, extra cellular matrix, angiogenesis leading pathways and influential factors of hypoxia on tumorigenesis and CSC survival have been elucidated. Finally, external factorial influence of oral microbiome gained due to the dysbiosis is also emphasized. There are growing confirmations of the possible roles of microbiomes in the progression of oral cancer. Given this, an attempt has been made to explore the potential links including EMT and signaling pathways towards resistance and stemness. This review provides a spectrum of understanding on stemness and progression of oral cancers at various regulatory levels along with their current therapeutic knowledge. These mechanisms could be exploited for future research to expand potential treatment strategies.

miRGediNET: A comprehensive examination of common genes in miRNA-Target interactions and disease associations: Insights from a grouping-scoring-modeling approach

In the broad and complex field of biological data analysis, researchers frequently gather information from a single source or database. Despite being a widespread practice, this has disadvantages. Relying exclusively on a single source can limit our comprehension as it may omit various perspectives that could be obtained by combining multiple knowledge bases. Acknowledging this shortcoming, we report on miRGediNET, a novel approach combining information from three biological databases. Our investigation focuses on microRNAs (miRNAs), small non-coding RNA molecules that regulate gene expression post-transcriptionally. We delve deeply into the knowledge of these miRNA's interactions with genes and the possible effects these interactions may have on different diseases. The scientific community has long recognized a direct correlation between the progression of specific diseases and miRNAs, as well as the genes they target. By using miRGediNET, we go beyond simply acknowledging this relationship. Rather, we actively look for the critical genes that could act as links between the actions of miRNAs and the mechanisms underlying disease. Our methodology, which carefully identifies and investigates these important genes, is supported by a strategic framework that may open up new possibilities for comprehending diseases and creating treatments. We have developed a tool on the Knime platform as a concrete application of our research. This tool serves as both a validation of our study and an invitation to the larger community to interact with, investigate, and build upon our findings. miRGediNET is publicly accessible on GitHub at https://github.com/malikyousef/miRGediNET, providing a collaborative environment for additional research and innovation for enthusiasts and fellow researchers.

Cancer stem cells of head and neck squamous cell carcinoma; distance towards clinical application; a systematic review of literature

Head and neck squamous cell carcinoma (HNSCC) is the major pathological type of head and neck cancer (HNC). The disease ranks sixth among the most common malignancies worldwide, with an increasing incidence rate yearly. Despite the development of therapy, the prognosis of HNSCC remains unsatisfactory, which may be attributed to the resistance to traditional radio-chemotherapy, relapse, and metastasis. To improve the diagnosis and treatment, the targeted therapy for HNSCC may be successful as that for some other tumors. Nanocarriers are the most effective system to deliver the anti-cancerous agent at the site of interest using passive or active targeting approaches. The system enhances the drug concentration in HCN target cells, increases retention, and reduces toxicity to normal cells. Among the different techniques in nanotechnology, quantum dots (QDs) possess multiple fluorescent colors emissions under single-source excitation and size-tunable light emission. Dendrimers are the most attractive nanocarriers, which possess the desired properties of drug retention, release, unaffecting by the immune system, blood circulation time enhancing, and cells or organs specific targeting properties. In this review, we have discussed the up-to-date knowledge of the Cancer Stem Cells of Head and Neck Squamous Cell Carcinoma. Although a lot of data is available, still much more efforts remain to be made to improve the treatment of HNSCC.

MYH9 Facilitates Cell Invasion and Radioresistance in Head and Neck Cancer via Modulation of Cellular ROS Levels by Activating the MAPK-Nrf2-GCLC Pathway

The MYH9 (Myosin heavy chain 9), an architecture component of the actomyosin cytoskeleton, has been reported to be dysregulated in several types of cancers. However, how this molecule contributes to cancer development is still obscure. This study deciphered the molecular function of MYH9 in head and neck cancer (HNC). Cellular methods included clonogenic survival, wound-healing migration, and Matrigel invasion assays. Molecular techniques included RT-qPCR, western blot, luciferase reporter assays, and flow cytometry. Clinical association studies were undertaken by TCGA data mining, Spearman correlation, and Kaplan-Meier survival analysis. We found that MYH9 was overexpressed in tumors and associated with poor prognosis in HNC patients. MYH9 promoted cell motility along with the modulation of the extracellular matrix (fibronectin, ITGA6, fascin, vimentin, MMPs). Also, MYH9 contributed to radioresistance and was related to the expression of anti-apoptotic and DNA repairing molecules (XIAP, MCL1, BCL2L1, ATM, RAD50, and NBN). Mechanically, MYH9 suppressed cellular ROS levels, which were achieved by activating the pan-MAPK signaling molecules (Erk, p38, and JNK), the induction of Nrf2 transcriptional activity, and the up-regulation of antioxidant enzymes (GCLC, GCLM, GPX2). The antioxidant enzyme GCLC was further demonstrated to facilitate cell invasion and radioresistance in HNC cells. Thus, MYH9 exerts malignant functions in HNC by regulating cellular ROS levels via activating the MAPK-Nrf2-GCLC signaling pathway. As MYH9 contributes to radioresistance and metastasis, this molecule may serve as a prognostic biomarker for clinical application. Furthermore, an in vivo study is emergent to support the therapeutic potential of targeting MYH9 to better manage refractory cancers.

Multifaceted and Intricate Oncogenic Mechanisms of NDRG1 in Head and Neck Cancer Depend on Its C-Terminal 3R-Motif

N-Myc downstream-regulated 1 (NDRG1) has inconsistent oncogenic functions in various cancers. We surveyed and characterized the role of NDRG1 in head and neck cancer (HNC). Cellular methods included spheroid cell formation, clonogenic survival, cell viability, and Matrigel invasion assays. Molecular techniques included transcriptomic profiling, RT-qPCR, immunoblotting, in vitro phosphorylation, immunofluorescent staining, and confocal microscopy. Prognostic significance was assessed by Kaplan–Meier analysis. NDRG1 participated in diverse oncogenic functions in HNC cells, mainly stress response and cell motility. Notably, NDRG1 contributed to spheroid cell growth, radio-chemoresistance, and upregulation of stemness-related markers (CD44 and Twist1). NDRG1 facilitated cell migration and invasion, and was associated with modulation of the extracellular matrix molecules (fibronectin, vimentin). Characterizing the 3R-motif in NDRG1 revealed its mechanism in the differential regulation of the phenotypes. The 3R-motif displayed minimal effect on cancer stemness but was crucial for cell motility. Phosphorylating the motif by GSK3b at serine residues led to its nuclear translocation to promote motility. Clinical analyses supported the oncogenic function of NDRG1, which was overexpressed in HNC and associated with poor prognosis. The data elucidate the multifaceted and intricate mechanisms of NDRG1 in HNC. NDRG1 may be a prognostic indicator or therapeutic target for refractory HNC.

CD44: A Multifunctional Mediator of Cancer Progression

CD44, a non-kinase cell surface transmembrane glycoprotein, has been widely implicated as a cancer stem cell (CSC) marker in several cancers. Cells overexpressing CD44 possess several CSC traits, such as self-renewal and epithelial-mesenchymal transition (EMT) capability, as well as a resistance to chemo- and radiotherapy. The CD44 gene regularly undergoes alternative splicing, resulting in the standard (CD44s) and variant (CD44v) isoforms. The interaction of such isoforms with ligands, particularly hyaluronic acid (HA), osteopontin (OPN) and matrix metalloproteinases (MMPs), drive numerous cancer-associated signalling. However, there are contradictory results regarding whether high or low CD44 expression is associated with worsening clinicopathological features, such as a higher tumour histological grade, advanced tumour stage and poorer survival rates. Nonetheless, high CD44 expression significantly contributes to enhanced tumourigenic mechanisms, such as cell proliferation, metastasis, invasion, migration and stemness; hence, CD44 is an important clinical target. This review summarises current research regarding the different CD44 isoform structures and their roles and functions in supporting tumourigenesis and discusses CD44 expression regulation, CD44-signalling pathways and interactions involved in cancer development. The clinical significance and prognostic value of CD44 and the potential of CD44 as a therapeutic target in cancer are also addressed.

Systematic Analysis and Identification of Dysregulated Panel lncRNAs Contributing to Poor Prognosis in Head-Neck Cancer

Head and neck cancer (HNC) is one of the most prevalent cancers worldwide, accounting for approximately 5% of all cancers. While the underlying molecules and their pathogenetic mechanisms in HNC have yet to be well elucidated, recent studies have shown that dysregulation of lncRNAs may disrupt the homeostasis of various biological pathways. However, the understanding of lncRNAs in HNC is still limited by the lack of expression profiling. In the present study, we employed a systematic strategy to identify a panel of lncRNA associated with HNC. A cancer-related lncRNA profile PCR array was screened to explore potential molecules specific for HNC. A total of 55 lncRNAs were found to be dysregulated in HNC cells when compared to normal keratinocytes. Further analysis of the prognostic significance using The Cancer Genome Atlas (TCGA) database revealed 15 lncRNAs highly correlated with overall survival in HNC patients. Additionally, clinical sample expression analysis of the TCGA-HNSC cohort revealed 16 highly dysregulated lncRNAs in HNC, resulting in a combined 31-lncRNA signature panel that could predict prognosis. Validation of these molecules confirmed the considerable level of altered expressions in HNC cells, with XIST, HOXA11-AS, TSIX, MALAT1, WT1-AS, and IPW being the most prominently dysregulated. We further selected a molecule from our panel (XIST) to confirm the validity of these lncRNAs in the regulation of cancer aggressiveness. Gene ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analyses demonstrated that XIST participated in various cancer-related functions, including cell proliferation and metastasis. XIST silencing with the RNAi technique substantially reduced invasion and migration in several HNC cell lines. Thus, our study defined a 31-lncRNA panel as prognostic signatures in HNC. These perspective results provide a knowledge foundation for further application of these molecules in precision medicine.

Roles of microRNAs in Regulating Cancer Stemness in Head and Neck Cancers

Head and neck squamous cell carcinomas (HNSCCs) are epithelial malignancies with 5-year overall survival rates of approximately 40-50%. Emerging evidence indicates that a small population of cells in HNSCC patients, named cancer stem cells (CSCs), play vital roles in the processes of tumor initiation, progression, metastasis, immune evasion, chemo-/radioresistance, and recurrence. The acquisition of stem-like properties of cancer cells further provides cellular plasticity for stress adaptation and contributes to therapeutic resistance, resulting in a worse clinical outcome. Thus, targeting cancer stemness is fundamental for cancer treatment. MicroRNAs (miRNAs) are known to regulate stem cell features in the development and tissue regeneration through a miRNA-target interactive network. In HNSCCs, miRNAs act as tumor suppressors and/or oncogenes to modulate cancer stemness and therapeutic efficacy by regulating the CSC-specific tumor microenvironment (TME) and signaling pathways, such as epithelial-to-mesenchymal transition (EMT), Wnt/β-catenin signaling, and epidermal growth factor receptor (EGFR) or insulin-like growth factor 1 receptor (IGF1R) signaling pathways. Owing to a deeper understanding of disease-relevant miRNAs and advances in in vivo delivery systems, the administration of miRNA-based therapeutics is feasible and safe in humans, with encouraging efficacy results in early-phase clinical trials. In this review, we summarize the present findings to better understand the mechanical actions of miRNAs in maintaining CSCs and acquiring the stem-like features of cancer cells during HNSCC pathogenesis.

MiR-520b inhibits endothelial activation by targeting NF-κB p65-VCAM1 axis

MiR-520b belongs to the miR-373/520 family, is expressed only in human and nonhuman primates. Previous reports indicated that the expression of miR-520b was repressed in human atherosclerotic plaque tissue compared with healthy vessels. However, the role of miR-520b in coronary artery disease still remains to be uncovered. In this study, we demonstrated that endothelial cells (ECs) in human atherosclerotic plaques expressed miR-520b and aimed to elucidate the impact of miR-520b on EC activation and inflammatory response. To determine the potential targets of miR-520b, we performed RNA-seq analysis by transfecting miR-520b mimics in ECs. The quantitative real-time PCR (qPCR) validation suggested that miR-520b over-expression reduced pro-inflammatory gene expression (e.g. ICAM1, VCAM1, SELE) while the inhibition of miR-520b induced their expression. By combining bioinformatics prediction and functional assays, we identified that RELA (Nuclear Factor-κB (NF-κB) Transcription Factor P65) was a direct target of miR-520b. Moreover, miR-520b mimics attenuated monocyte adhesion and monocyte trans-endothelial migration (the initial steps of atherosclerotic formation) in response to lipopolysaccharides (LPS) stimulation. Re-expression of a non-miR-targetable version of p65 could rescue the reduced monocyte cell attachment, suggesting that this process is NF-κB p65 dependent. MiR-520b reduced the abundance of NF-κB p65 in cytoplasmic fractions without corresponding increase in nuclear fractions, indicating that this regulation is independent of p65 translocation process. MiR-520b mimics attenuated the activity of VCAM-1 promoter, whereas miR-520b inhibitor activated its activity. However, miR-520b inhibitor had no effect on promoter activity containing the mutated NF-κB p65 binding sites, strongly demonstrating that the impact of miR-520b on VCAM1 gene is mediated by NF-κB p65. Thus, we concluded that miR-520b suppressed EC inflammation and the cross-talk between monocytes and ECs by down-regulating NF-κB p65-ICAM1/VCAM1 axis and might serve as a potential therapeutic target for EC dysfunction and atherosclerosis.

FGF16 regulated by miR-520b enhances the cell proliferation of lung cancer

FGF16 is implicated in the progression of some specific types of cancers, such as embryonic carcinoma, ovarian cancer, and liver cancer. Yet, the function of FGF16 in the development of lung cancer remains largely unexplored. In this study, we present the novel function of FGF16 and the regulation of miR-520b on FGF16 in lung cancer progression. In clinical lung cancer tissues, FGF16 is overexpressed and its high level is negatively associated with the low level of miR-520b. Furthermore, both the transcription and translation levels of FGF16 are restrained by miR-520b in lung cancer cells. For the regulatory mechanism investigation, miR-520b is able to directly bind to the 3′-untranslated region (3′UTR) of FGF16 mRNA, leading to its mRNA cleavage in the cells. Functionally, miR-520b reduces the growth of lung cancer and its inhibitor anti-miR520b is able to promote the growth through competing endogenous miR-520b. Moreover, FGF16 silence using RNA interference is capable of doing great damage to anti-miR-520b-accelerated growth of lung cancer. Thus, our finding indicates that FGF16 is a new target gene of miR-520b in lung cancer. For lung cancer, FGF16 may serve as a novel biomarker and miR-520b/FGF16 may be useful in clinical treatment.

MicroRNA-363-3p inhibits tumor cell proliferation and invasion in oral squamous cell carcinoma cell lines by targeting SSFA2

The aim of the present study was to evaluate the expression levels of microRNA (miR)-363-3p and its underlying physiological function in oral squamous cell carcinoma (OSCC). miR-363-3p expression levels were measured in OSCC cell lines using reverse transcription-quantitative PCR. The role of miR-363-3p in OSCC cells was examined using gain-of-function assays in vitro. Cell proliferation was assessed using Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine assays and flow cytometry. Cell migration and invasion were evaluated in wound-healing and Transwell Matrigel assays. In addition, bioinformatics analysis predicted binding sites of miR-363-3p on sperm-specific antigen 2 (SSFA2). Luciferase reporter and RNA pull-down assays were conducted to test whether miR-363-3p interacted with SSFA2. miR-363-3p expression was downregulated in OSCC cell lines compared with that in the normal epithelial cell line (NHOK). Additionally, miR-363-3p overexpression suppressed OSCC cell proliferation, migration and invasion in vitro. SSFA2 was verified as a direct target of miR-363-3p, and SSFA2 overexpression partially counteracted the inhibitory effects of miR-363-3p on cell proliferation, migration and invasion in OSCC cell lines. Thus, miR-363-3p may serve as a tumor suppressor via targeting SSFA2 and may represent a potential therapeutic target for OSCC.

A multi-omics study on cutaneous and uveal melanoma

AIM

To present the multi-omics landscape of cutaneous melanoma (CM) and uveal melanoma (UM) from The Cancer Genome Atlas (TCGA).

METHODS

The differentially expressed genes (DEGs) between CM and UM were found and integrated into a gene ontology enrichment analysis. Besides, the differentially expressed miRNAs were also identified. We also compared the methylation level of CM with UM and identified the differentially methylated regions to integrate with the DEGs to display the relationship between the gene expression and DNA methylation. The differentially expressed transcription factors (TFs) were identified.

RESULTS

Though CM had more mutational burden than UM, they shared several similarities such as the same rankings in diverse variant types. Except GNAQ and GNA11, the other top 18 mutated genes of the combined group were mostly detected in CM instead of UM. On the transcriptomic level, 4610 DEGs were found and integrated into a gene ontology enrichment analysis. We also identified 485 differentially expressed miRNAs. The methylation analysis showed that UM had a significantly higher methylation level than CM. The integration of differentially methylated regions and DEGs demonstrated that most DEGs were downregulated in UM and the hypo- and hypermethylation presented no obvious difference within these DEGs. Finally, 116 hypermethylated TFs and 114 hypomethylated TFs were identified as differentially expressed TFs in CM when compared with UM.

CONCLUSION

This multi-omics study on comparing CM with UM confirms that they differ in all analyzed levels. Of notice, the results also offer new insights with implications for elucidating certain unclear problems such as the distinct role of epithelial mesenchymal transition in two melanomas, the different metastatic routes of CM and UM and the liver tropism of metastatic UM.

hsa-miR-9-5p Down-Regulates HK2 and Confers Radiosensitivity to Nasopharyngeal Carcinoma

BACKGROUND

This study was designed to explore the effects of hsa-miR-9-5p on radiotherapy sensitivity of nasopharyngeal carcinoma (NPC) by targeting hexokinase 2 (HK2).

METHODS

The levels of hsa-miR-9-5 and HK2 in NPC patients and radiosensitive and resistant cells were determined using qRT-PCR. The dual luciferase reporter gene system was used to determine hsa-miR-9-5p targeting HK2. The level of HK2 expression in NPC were determined using qRT-PCR and western blotting after the administration of hsa-miR-9-5p agomir. The effects of hsa-miR-9-5p on proliferation and apoptosis with or without irradiation (IR) were examined using CCK-8, flow cytometry and colony formation assays. (18F)-Flourodeoxyglucose uptake was used to evaluate the growth of tumor with or without radiation therapy in vivo.

RESULTS

hsa-miR-9-5p target to inhibit HK2. Moreover, the cell proliferation was seen in a decreased trend while the cell apoptosis increased in the hsa-miR-9-5p group following radiation therapy hsa-miR-9-5p also showed a significant inhibitory effect on the growth of tumor in vivo with radiation therapy.

CONCLUSIONS

hsa-miR-9-5p improved the radiosensitivity of NPC by targeting HK2.

MiR-520b inhibits proliferation, migration and invasion in gallbladder carcinoma by targeting RAB22A

INTRODUCTION

Previous studies have reported that miR-520b exhibited inhibitory effects on various human tumors, whereas the effects of miR-520b on gallbladder carcinoma (GBC) have remained unclear. To investigate the effects of miR-520b on GBC progression and reveal the underlying mechanisms, this study was performed.

MATERIAL AND METHODS

MiR-520b and RAB22A mRNA levels were analyzed by quantitative real-time PCR (qPCR). RAB22A protein level was analyzed via Western blot and immunohistochemical (IHC) analysis. The proliferation, colony formation ability, migration and invasion of NOZ cells were measured via MTT, colony formation, wound healing and transwell invasion assay respectively.

RESULTS

MiR-520b expression level was lower in human GBC tissues than that in neighboring normal tissues. MiR-520b mimic repressed NOZ cell proliferation, colony formation ability, migration and invasion, whereas miR-520b inhibitor exhibited opposite effects. Dual luciferase reporter assay confirmed that miR-520b could bind to the 3'-untranslated regions of RAB22A mRNA. Moreover, RAB22A overexpression significantly abolished the anti-tumor effects of miR-520b in a NOZ cell model. Western blot, qPCR and IHC analysis proved that human GBC tissues showed a higher RAB22A expression level than neighboring normal tissues. Additionally, there was a negative association between miR-520b and RAB22A expression.

CONCLUSIONS

MiR-520b had suppressive effects on GBC via targeting RAB22A in vitro.

IncRNA MAPKAPK5-AS1 promotes proliferation and migration of thyroid cancer cell lines by targeting miR-519e-5p/YWHAH

Thyroid cancer is a common malignant tumour of the endocrine system and ranks ninth in cancer incidence worldwide. An extensive body of evidence has demonstrated that lncRNAs play a critical role in the progression of thyroid cancer. The lncRNA MAPKAPK5-AS1 has been reported to be abnormally expressed and to play a role in the development of various human cancers. However, MAPKAPK5-AS1's potential role in thyroid cancer progression remains unknown. The objective of our study was to explore the role and mechanism of MAPKAPK5-AS1 in thyroid cancer cells and provide a potential target for its biological diagnosis and treatment. We transfected sh-MAPKAPK5-AS1 and sh-NC into BCPAP and TPC-1 cells for loss-of-function assays. Results of RT-qPCR analysis demonstrated that MAPKAPK5-AS1 was more highly expressed in thyroid cancer cells compared to normal cells. Functional assays demonstrated that interfering with the expression of MAPKAPK5-AS1 notably repressed proliferation and invasion and accelerated apoptosis of BCPAP and TPC-1 cells. Mechanistically, we found that miR-519e-5p was negatively regulated by MAPKAPK5-AS1 and that tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein eta (YWHAH) was a target of miR-519e-5p. Additionally, rescue assays demonstrated that downregulation of MAPKAPK5-AS1 expression inhibited cell proliferation, migration, and invasion and promoted apoptosis by sponging miR-519e-5p, thereby increasing YWHAH expression. Ultimately, our study revealed that MAPKAPK5-AS1 promotes proliferation and migration of thyroid cancer cells by targeting the miR-519e-5p/YWHAH axis, which provides novel insight into the development and progression of thyroid cancer.

LncRNA HOTAIR enhances breast cancer radioresistance through facilitating HSPA1A expression via sequestering miR-449b-5p

Background

Breast cancer (BRCA) is the leading cause of cancer‐related death in women worldwide. Pre‐ and postoperative radiotherapy play a pivotal role in BRCA treatment but its efficacy remains limited and plagued by the emergence of radiation resistance, which aggravates patient prognosis. The long noncoding RNA (lncRNA)‐implicated mechanisms underlying radiation resistance are rarely reported. The aim of this study was to determine whether lncRNA HOX transcript antisense RNA (HOTAIR) modulated the radiosensitivity of breast cancer through HSPA1A.

Methods

A Gammacell 40 Exactor was used for irradiation treatment. Bioinformatic tools and luciferase reporter assay were adopted to explore gene expression profile and demonstrate the interactions between lncRNA, miRNA and target mRNA 3′‐untranslated region (3′‐UTR). The expression levels of certain genes were determined by real‐time PCR and western‐blot analyses. in vitro and in vivo functional assays were conducted by cell viability and tumorigenicity assays.

Results

The levels of oncogenic lncRNA HOTAIR were positively correlated with the malignancy of BRCA but reversely correlated with the radiosensitivity of breast cancer cells. Moreover, the expression levels of HOTAIR were positively associated with those of heat shock protein family A (Hsp70) member 1A (HSPA1A) in clinical BRCA tissues and HOTAIR upregulated HSPA1A at the mRNA and protein levels in irradiated BRCA cells. Mechanistically, miR‐449b‐5p restrained HSPA1A expression through targeting the 3′‐UTR of HSPA1A mRNA, whereas HOTAIR acted as a competing sponge to sequester miR‐449b‐5p and thereby relieved the miR‐449b‐5p‐mediated HSPA1A repression. Functionally, HOTAIR conferred decreased radiosensitivity on BRCA cells, while miR‐449b‐5p overexpression or HSPA1A knockdown abrogated the HOTAIR‐enhanced BRCA growth under the irradiation exposure both in vitro and in vivo.

Conclusions

LncRNA HOTAIR facilitates the expression of HSPA1A by sequestering miR‐449b‐5p post‐transcriptionally and thereby endows BRCA with radiation resistance.

Key points

Therapeutically, HOTAIR and HSPA1A may be employed as potential targets for BRCA radiotherapy. Our findings shed new light into the mechanism by which lncRNAs modulate the radiosensitivity of tumors.

MiR-223-3p promotes cell proliferation and metastasis by downregulating SLC4A4 in clear cell renal cell carcinoma

MicroRNAs (miRNAs) are known to affect the occurrence and progression of cancer. We therefore evaluated the involvement of miR-223-3p in renal cell cancer. MiR-223-3p was highly expressed in clear cell renal cell cancer tissues. Clear cell renal cell cancer patients with higher miR-223-3p expression had higher tumor stages and grades and poorer prognoses. In renal cancer cells, overexpression of miR-223-3p enhanced cell proliferation and metastasis, while inhibition of miR-223-3p reduced the malignant capacity of the cells. MiR-223-3p was found to bind directly to solute carrier family 4, member 4 (SLC4A4) mRNA, thereby reducing SLC4A4 mRNA and protein expression. SLC4A4 overexpression restrained cell proliferation and metastasis by suppressing Kirsten rat sarcoma viral oncogene (KRAS) expression in renal cancer cells. SLC4A4 expression correlated negatively with miR-223-3p expression in patient samples. Given that miR-223-3p suppressed the SLC4A4/KRAS axis, miR-223-3p gene therapy could be an effective treatment for renal cancer.

MLK3 is a newly identified microRNA-520b target that regulates liver cancer cell migration

The roles of microRNAs (miRNAs) in liver cancer have attracted much attention in recent years. In this study, we demonstrate that miR-520b is downregulated in MHCC-97H cells, a liver cancer cell line with high potential of metastasis, compared with MHCC-97L cells which has a low potential of metastasis. Furthermore, the enhanced expression of miR-520b could inhibit liver cancer cell migration, while silencing its expression resulted in increased migration. Mixed lineage kinase 3 (MLK3) was identified as a direct and functional new target of miR-520b. This regulation was also confirmed by luciferase reporter assays. In addition, our results showed that overexpression of the MLK3 expression partially reversed the effect of miR-520b on liver cancer cell migration, indicating that MLK3 contributes to the migration in liver cancer. The newly identified miR-520b/MLK3 axis partially elucidates the molecular mechanism of liver cancer cell migration and represents a new potential therapeutic target for liver cancer treatment.

LncRNA FGD5-AS1 can be predicted as therapeutic target in oral cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) have been extensively studied to participate in the carcinogenesis of various tumors. LncRNA FGD5-AS1 has been studied as an oncogene in several cancers; however, the role it plays in oral squamous cell carcinoma (OSCC) still remains unclear.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assess relevant RNAs expression. CCK-8 and colony formation were combined to investigate cell proliferation. Flow cytometry was implemented to test the apoptosis of cell. Wound healing assay and transwell assays were conducted to investigate cell migration and invasion. Western blot assay was conducted to measure relevant protein expression.

RESULTS

FGD5-AS1 expression was aberrantly up-regulated in OSCC tissue and cells. FDG5-AS1 up-regulation induced USP21 overexpression advances OSCC development. Knockdown of FGD5-AS1 inhibited cell growth, migration, and invasion, yet promoted apoptosis.

CONCLUSION

FGD5-AS1 regulates OSCC via competitively binding to miR-520b against USP21. It could become a potential diagnostic biomarker for OSCC.

Characterizing CD44 regulatory microRNAs as putative therapeutic agents in human melanoma

The multistructural and multifunctional transmembrane glycoprotein CD44 is overexpressed in many tumors of distinct origin including malignant melanoma and contributes to a poor prognosis by affecting cell proliferation, cell migration, and also the sensitivity for apoptosis induction. Previous studies reported so far 15 CD44 regulatory microRNAs (miRs) in different cell systems. Using a novel method for miR affinity purification miR-143-3p was identified as most potent binder to the 3' untranslated region (UTR) of CD44. Overexpression of miR-143-3p in melanoma cells inhibits CD44 translation, which is accompanied by a reduced proliferation, migration and enhanced daunorubicin induced apoptosis of melanoma cells in vitro. Analyses of discordant CD44 and miR-143-3p expression levels in human melanocytic nevi and dermal melanoma samples demonstrated medium to high CD44 levels with no association to tumor grading or staging. The CD44 expression correlated to PD-L1, but not to MART-1 expression in malignant melanoma. Interestingly, the CD44 expression was inversely correlated to the infiltration of pro-inflammatory immune effector cells. In conclusion, the tumor suppressive miR-143-3p was identified as the most potent CD44 inhibitory miR, which affects growth characteristics of melanoma cells suggesting the implementation of miR-143-3p as as a potential anti-CD44 therapy of malignant melanoma.

The DNMT1/miR-34a Axis Is Involved in the Stemness of Human Osteosarcoma Cells and Derived Stem-Like Cells

The DNA methyltransferase 1 (DNMT1)/miR-34a axis promoted carcinogenesis of various types of cancers. However, no literature reported its contribution to the stemness of osteosarcoma cancer stem-like cells (OSLCs). We sought to determine whether the DNMT1/miR-34a axis facilitates the stemness of OSLCs. We here revealed the higher DNMT1 activity and expression, lower miR-34a expression with high methylation of its promoter, and stronger stemness of OSLCs, as manifested by elevated sphere and colony formation capacities; CD133, CD44, ABCG2, Bmi1, Sox2, and Oct4 protein amounts in vitro; and carcinogenicity in a nude mouse xenograft model, when compared to the parental U2OS cells. 5-Azacytidine (Aza-dC) repressed DNMT1 activation and upregulated miR-34a expression by promoter demethylation and suppressed the stemness of OSLCs in a dose-dependent manner. DNMT1 knockdown increased miR-34a and reduced the stemness of OSLCs. Transfection with a miR-34a mimic repressed the stemness of OSLCs but did not alter DNMT1 activity and expression. Conversely, DNMT1 overexpression declined miR-34a levels, promoting the stemness of U2OS cells. Transfection with a miR-34a inhibitor enhanced the stemness of U2OS cells, without affecting the DNMT1 activity and expression. Importantly, reexpression of miR-34a could rescue the effects of DNMT1 overexpression on miR-34a inhibition as well as the stemness promotion without affecting the activity and expression of DNMT1. Our results revealed that aberrant activation of DNMT1 caused promoter methylation of miR-34a, leading to miR-34a underexpression, and the role of the DNMT1/miR-34a axis in promoting and sustaining the stemness of OSLCs.

Identification of microRNAs associated with the aggressiveness of prolactin pituitary tumors using bioinformatic analysis

Aggressive prolactin pituitary tumors, which exhibit aggressive behaviors and resistance to conventional treatments, are a huge challenge for neurosurgeons. Many studies have investigated the roles of microRNAs (miRNAs) in pituitary tumorigenesis, invasion and metastasis, but few have explored aggressiveness‑associated miRNAs in aggressive pituitary tumors. Differentially expressed miRNAs (DEMs) between aggressive and nonaggressive prolactin pituitary tumors were screened using the GSE46294 miRNA expression profile downloaded from the GEO database. The potential target genes of the top three most highly upregulated and downregulated DEMs were predicted by miRTarBase, and potential functional annotation and pathway enrichment analysis were performed using the DAVID database. Protein‑protein interaction (PPI) and miRNA‑hub gene interaction networks were constructed by Cytoscape software. A total of 43 DEMs were identified, including 19 upregulated and 24 downregulated miRNAs, between aggressive and nonaggressive prolactin pituitary tumors. One hundred and seventy and 680 target genes were predicted for the top three most highly upregulated and downregulated miRNAs, respectively, and these genes were involved in functional enrichment pathways, such as regulation of transcription from RNA polymerase II promoter, DNA‑templated transcription, Wnt signaling pathway, protein binding, and transcription factor activity (sequence‑specific DNA binding). In the PPI network, the top 10 genes with the highest degree of connectivity of the upregulated and downregulated DEMs were selected as hub genes. By constructing an miRNA‑hub gene network, it was found that most hub genes were potentially modulated by hsa‑miR‑489 and hsa‑miR‑520b. Targeting hsa‑miR‑489 and hsa‑miR‑520b may provide new clues for the diagnosis and treatment of aggressive prolactin pituitary tumors.

MiR-520b promotes the progression of non-small cell lung cancer through activating Hedgehog pathway

Although the non-small cell lung cancer (NSCLC) is one of the most malignant tumours worldwide, the mechanisms controlling NSCLC tumourigenesis remain unclear. Here, we find that the expression of miR-520b is up-regulated in NSCLC samples. Further studies have revealed that miR-520b promotes the proliferation and metastasis of NSCLC cells. In addition, miR-520b activates Hedgehog (Hh) pathway. Inhibitor of Hh pathway could relieve the oncogenic effect of miR-520b upon NSCLC cells. Mechanistically, we demonstrate that miR-520b directly targets SPOP 3'-UTR and decreases SPOP expression, culminating in GLI2/3 stabilization and Hh pathway hyperactivation. Collectively, our findings unveil that miR-520b promotes NSCLC tumourigenesis through SPOP-GLI2/3 axis and provide miR-520b as a potential diagnostic biomarker and therapeutic target for NSCLC.

MiR-520b restrains cell growth by targeting HDAC4 in lung cancer

BACKGROUND

MicroRNAs (miRNAs) function as tumor promoting or tumor suppressing factors in many cancers. MiR-520b contributes to progression in head-neck and liver cancers, spinal osteosarcoma, and glioma; however, the association of miR-520b with lung cancer progression remains unknown. In this investigation, we explore the effect of miR-520b targeting HDAC4 on lung cancer growth.

METHODS

The regulation of miR-520b or its inhibitor on HDAC4 expression was analyzed using Western blot analysis. After treatment of miR-520b or its inhibitor, miR-520b and HDAC4 levels were examined using quantitative real time-PCR. The modulation of miR-520b on HDAC4 was investigated by luciferase reporter gene assay. Cell proliferation evaluation was performed using colony formation and methyl-thiazolyl-tetrazolium assays. The correlation between miR-520b and HDAC4 in human clinical samples was verified using Pearson's correlation coefficient.

RESULTS

An obvious decrease in HDAC4 expression was observed in lung cancer A549 cells treated with different doses of miR-520b. The miR-520b inhibitor enhanced HDAC4 expression in lung cancer cells. Bioinformatics predicted the targeting of miR-520b on HDAC4. MiR-520b directly targeted the 3' untranslated region of HDAC4. The introduction of miR-520b obviously inhibited cell proliferation in vitro. Anti-miR-520b was capable of accelerating lung cancer cell proliferation; however, HDAC4 knockdown destroyed anti-miR-520b-induced cell proliferation. Finally, a negative correlation between miR-520b and HDAC4 was observed in clinical human lung cancer samples.

CONCLUSION

MiR-520b decreases HDAC4 expression to control cell proliferation in lung cancer.

Role of miR-520b in non-small cell lung cancer

The aim of the present study was to investigate the expression of microRNA (miR)-520b in non-small cell lung cancer (NSCLC) and its biological functions. Reverse transcription-quantitative polymerase chain reaction was used to detect the expression of miR-520b in 52 cases of NSCLC tissues, and its associations with tumor clinical staging and lymph node metastasis were analyzed. miR-520b mimics was transfected into A549 and Calu-3 cells. Cell proliferation, cell cycle, and cell invasion and migration abilities were assessed via cell counting kit-8 assay, flow cytometry and Transwell chamber assay, respectively. Western blot analysis was performed to detected protein expression levels, and dual luciferase reporter assay was used to detect the gene interaction. miR-520b expression was significantly downregulated in NSCLC. The expression of miR-520b in tumor tissues at N1 stage was lower than that at the N0 stage. miR-520b expression was negatively associated with clinical TNM staging. Furthermore, miR-520b mimic transfection inhibited the proliferation and invasion and metastasis abilities of A549 and Calu-3 cells. The expression of Rab22A was downregulated in the miR-520b mimics-transfected cells, whereas E-cadherin expression was increased, and vimentin expression was downregulated. Dual luciferase reporter assay demonstrated that miR-520b directly targeted the expression of Rab22A. Furthermore, Rab22A reversal downregulated the inhibitory effect of miR-520b. miR-520b expression was downregulated in NSCLC, which was negatively correlated with lymph node metastasis and TNM staging. miR-520b targeted on Rab22A to work as a tumor suppressor, inhibiting tumor proliferation and metastasis.

In silico identification of microRNAs predicted to regulate N-myristoyltransferase and Methionine Aminopeptidase 2 functions in cancer and infectious diseases

Protein myristoylation is a key protein modification carried out by N-Myristoyltransferase (NMT) after Methionine aminopeptidase 2 (MetAP2) removes methionine from the amino-terminus of the target protein. Protein myristoylation by NMT augments several signaling pathways involved in a myriad of cellular processes, including developmental pathways and pathways that when dysregulated lead to cancer or immune dysfunction. The emerging evidence pointing to NMT-mediated myristoylation as a major cellular regulator underscores the importance of understanding the framework of this type of signaling event. Various studies have investigated the role that myristoylation plays in signaling dysfunction by examining differential gene or protein expression between normal and diseased states, such as cancers or following HIV-1 infection, however no study exists that addresses the role of microRNAs (miRNAs) in the regulation of myristoylation. By performing a large scale bioinformatics and functional analysis of the miRNAs that target key genes involved in myristoylation (NMT1, NMT2, MetAP2), we have narrowed down a list of promising candidates for further analysis. Our condensed panel of miRNAs identifies 35 miRNAs linked to cancer, 21 miRNAs linked to developmental and immune signaling pathways, and 14 miRNAs linked to infectious disease (primarily HIV). The miRNAs panel that was analyzed revealed several NMT-targeting mRNAs (messenger RNA) that are implicated in diseases associated with NMT signaling alteration, providing a link between the realms of miRNA and myristoylation signaling. These findings verify miRNA as an additional facet of myristoylation signaling that must be considered to gain a full perspective. This study provides the groundwork for future studies concerning NMT-transcript-binding miRNAs, and will potentially lead to the development of new diagnostic/prognostic biomarkers and therapeutic targets for several important diseases.

Midazolam induces A549 cell apoptosis in vitro via the miR-520d-5p/STAT3 pathway

A novel microRNA, miR-520d-5p, can inhibit proliferation of osteosarcoma cells, but the biological role of miR-520d-5p in lung cancer is notknown. Midazolam can induce apoptosis in many kinds of cancer cells, but there are no reportson its use in lung cancer. We investigated the roles of midazolam and miR-520d-5p in apoptosis induction in a non-small cell lung cancer (NSCLC) cell line (A549). The expression of miR-520d-5p, a signal transducer and activator of transcription 3 (STAT3) and its related protein were measured by quantitative real-time PCR and Western blot. Apoptosis of the NSCLC cells in response to midazolam was determined by MTT assay, flow cytometry, and Western blot. Midazolam significantly induced A549 cell apoptosis and modulated expression of Bcl-2, Bax, and Caspase-3. Additionally, midazolam regulated STAT3 expression in A549 cells, and the siRNA inhibited STAT3 levels, highlighting their roles in the regulation of STAT3 signaling. Midazolam combined with the miR-520d-5p mimic and inhibitor, regulated STAT3 expression and its signaling pathway. Midazolam combined with the miR-520d-5p mimic significantly induced A549 cell apoptosis. Thus, midazolam can induce apoptosis of A549 cells by targeting STAT3 via miR-520d-5p. These findings suggest that midazolam might be a putative anti-cancer approach for NSCLC therapy.

Apigenin sensitizes hepatocellular carcinoma cells to doxorubic through regulating miR-520b/ATG7 axis

Chemo-resistance is a serious obstacle for successful treatment of cancer. Apigenin, a dietary flavonoid, has been reported as an anticancer drug in various malignant cancers. This study aimed to investigate the potential chemo-sensitization effect of apigenin in doxorubicin-resistant hepatocellular carcinoma cell line BEL-7402/ADM. We observed that apigenin significantly enhanced doxorubicin sensitivity, induced miR-520b expression and inhibited ATG7-dependent autophagy in BEL-7402/ADM cells. In addition, we also showed that miR-520b mimics increased doxorubicin sensitivity and inhibited ATG7-dependent autophagy. Meanwhile, we indicated that ATG7 was a potential target of miR-520b. Furthermore, APG inhibited the growth of hepatocellar carcinoma xenografts in nude mice by up-regulating miR-520b and inhibiting ATG7. Our finding provides evidence that apigenin sensitizes BEL-7402/ADM cells to doxorubicin through miR-520b/ATG7 pathway, which furtherly supports apigenin as a potential chemo-sensitizer for hepatocellular carcinoma.

Unveiling massive numbers of cancer-related urinary-microRNA candidates via nanowires

Analyzing microRNAs (miRNAs) within urine extracellular vesicles (EVs) is important for realizing miRNA-based, simple, and noninvasive early disease diagnoses and timely medical checkups. However, the inherent difficulty in collecting dilute concentrations of EVs (<0.01 volume %) from urine has hindered the development of these diagnoses and medical checkups. We propose a device composed of nanowires anchored into a microfluidic substrate. This device enables EV collections at high efficiency and in situ extractions of various miRNAs of different sequences (around 1000 types) that significantly exceed the number of species being extracted by the conventional ultracentrifugation method. The mechanical stability of nanowires anchored into substrates during buffer flow and the electrostatic collection of EVs onto the nanowires are the two key mechanisms that ensure the success of the proposed device. In addition, we use our methodology to identify urinary miRNAs that could potentially serve as biomarkers for cancer not only for urologic malignancies (bladder and prostate) but also for nonurologic ones (lung, pancreas, and liver). The present device concept will provide a foundation for work toward the long-term goal of urine-based early diagnoses and medical checkups for cancer.

MicroRNA-142-5p induces cancer stem cell-like properties of cutaneous squamous cell carcinoma via inhibiting PTEN

Cutaneous squamous cell carcinoma (cSCC) is a malignancy of keratinocyte-derived skin tumor, which is regarded as the second most common skin cancer worldwide. Accumulating evidence has established that microRNAs (miRNAs) can play a critical role in tumor initiation, progression, and metastasis including cSCC. Abnormal expression of hsa-miR-142-5p has been elaborated in various tumors. Nevertheless, its expression and function in the development of cSCC remain unclear. In our study, we found that the expression of hsa-miR-142-5p in cSCC cells were greatly overexpressed compared to human benign epidermal keratinocyte cells. Moreover, inhibited hsa-miR-142-5p can repress cSCC cell growth and induce apoptosis while upregulated hsa-miR-142-5p exhibited a reverse phenomenon. Recently, cancer stem cells (CSCs) which possess the ability of self-renewal and proliferation and are able to produce cancer cells have been widely reported. However, the correlation between hsa-miR-142-5p and CSCs in cSCC is still unknown. Interestingly, we observed that overexpressing hsa-miR-142-5p can induce CSC-like properties in cSCC via activating Wnt signaling. In addition, the luciferase reporter assay data and bioinformatics analysis demonstrated that hsa-miR-142-5p can target the 3'UTR of PTEN mRNA. Taken these together, we draw a conclusion that hsa-miR-142-5p can trigger cancer stem cell-like properties of cSCC through inhibition of PTEN. Our findings may provide hsa-miR-142-5p as a new therapeutic target for cSCC.