The miR-205-5p/BRCA1/RAD17 Axis Promotes Genomic Instability in Head and Neck Squamous Cell Carcinomas

Role of Non-coding RNAs on the Radiotherapy Sensitivity and Resistance in Cancer Cells

Radiotherapy (RT) is an integral part of treatment management in cancer patients. However, one of the limitations of this treatment method is the resistance of cancer cells to radiotherapy. These restrictions necessitate the introduction of modalities for the radiosensitization of cancer cells. It has been shown that Noncoding RNAs (ncRNAs), along with modifiers, can act as radiosensitivity and radioresistant regulators in a variety of cancers by affecting double strand break (DSB), wnt signaling, glycolysis, irradiation induced apoptosis, ferroptosis and cell autophagy. This review will provide an overview of the latest research on the roles and regulatory mechanisms of ncRNA after RT in in vitro and preclinical researches.

Polo-like kinase 2 targeting as novel strategy to sensitize mutant p53-expressing tumor cells to anticancer treatments

Polo-like kinase 2 (Plk2) belongs to a family of serine/threonine kinases, and it is involved in tumorigenesis of diverse kind of tissues. We previously reported that Plk2 gene was a transcriptional target of the mutant p53/NF-Y oncogenic complex. Plk2 protein can bind to and phosphorylate mutant p53 triggering an oncogenic autoregulatory feedback loop involved in cancer cell proliferation and chemoresistance. In this study, we aimed to assess whether the specific inhibition of Plk2 kinase activity by the selective TC-S 7005 inhibitor could decrease cell proliferation and migration inhibiting mutant p53 phosphorylation, thus disarming its oncogenic potential. We found that the Plk2 inhibitor treatment sensitized the cells to the irradiation and chemotherapy drugs, thereby overcoming the mutant p53-dependent chemoresistance. Taken together, we provided results that Plk2 could be considered a tractable pharmacological target for cancers expressing mutant p53 proteins. The combined treatment with conventional chemotherapeutic drugs and Plk2 inhibitors may represent a new candidate intervention approach, which may be considered for improving tumor cell sensitivity to DNA damaging drugs. KEY MESSAGES : Missense mutations are present in the TP53 gene in about half of all human cancers and correlate with poor patient outcome. Mutant p53 proteins exert gain of function (GOF) activities in tumor cells such as increased proliferation, genomic instability and resistance to therapies. Polo-like kinase 2 (PLK2) binds and phosphorylates mutant p53 protein strengthening its GOF activities. Pharmacologically targeting PLK2 weakens mutant p53 proteins and sensitizes tumor cells to therapeutic treatments.

Tumor-exosomal miR-205-5p as a diagnostic biomarker for colorectal cancer

BACKGROUND

Tumor-derived exosomal miRNAs play crucial roles in cancer diagnosis. Current studies aim to identify exosomal miRNAs associated with colorectal cancer (CRC) that are noninvasive, sensitive, and specific.

PATIENTS AND METHODS

Exosomes were extracted from CRC patients and healthy donors via ultracentrifugation, followed by verification via transmission electron microscopy (TEM), qNano, and Western blot analysis. The differential expression levels and clinical characteristics of miR-205-5p were analyzed in CRC via data from The Cancer Genome Atlas (TCGA). Real-time quantitative PCR was used to assess the expression levels of exosomal miRNAs in 157 primary CRC patients, 20 patients with benign diseases, and 135 healthy donors. Predictions regarding target genes were made to guide further exploration of the disease's etiopathogenesis through bioinformatics.

RESULTS

Compared with that in healthy donors, the expression of miR-205-5p in colorectal cancer (CRC) patients was significantly lower, as determined through analysis of the TCGA database. We conducted a prediction and analysis of the functional enrichment of downstream target genes regulated by miR-205-5p. A lower level of exosomal miR-205-5p in the serum of CRC patients than in that of healthy controls (p < 0.0001) and patients with benign disease (p < 0.0001) was observed. Furthermore, the expression levels of exosomal miR-205-5p were significantly lower in early-stage CRC patients than in the comparison groups (p<0.001 and p < 0.0001). Notably, the expression levels of exosomal miR-205-5p significantly increased postoperatively (p = 0.0053).

CONCLUSIONS

The present study demonstrated that serum exosomal miR-205-5p may be a diagnostic biomarker for CRC.

Kinome-Wide Synthetic Lethal Screen Identifies PANK4 as a Modulator of Temozolomide Resistance in Glioblastoma

Temozolomide (TMZ) represents the cornerstone of therapy for glioblastoma (GBM). However, acquisition of resistance limits its therapeutic potential. The human kinome is an undisputable source of druggable targets, still, current knowledge remains confined to a limited fraction of it, with a multitude of under-investigated proteins yet to be characterized. Here, following a kinome-wide RNAi screen, pantothenate kinase 4 (PANK4) isuncovered as a modulator of TMZ resistance in GBM. Validation of PANK4 across various TMZ-resistant GBM cell models, patient-derived GBM cell lines, tissue samples, as well as in vivo studies, corroborates the potential translational significance of these findings. Moreover, PANK4 expression is induced during TMZ treatment, and its expression is associated with a worse clinical outcome. Furthermore, a Tandem Mass Tag (TMT)-based quantitative proteomic approach, reveals that PANK4 abrogation leads to a significant downregulation of a host of proteins with central roles in cellular detoxification and cellular response to oxidative stress. More specifically, as cells undergo genotoxic stress during TMZ exposure, PANK4 depletion represents a crucial event that can lead to accumulation of intracellular reactive oxygen species (ROS) and subsequent cell death. Collectively, a previously unreported role for PANK4 in mediating therapeutic resistance to TMZ in GBM is unveiled.

Signaling Pathway Alterations Driven by BRCA1 and BRCA2 Germline Mutations are Sufficient to Initiate Breast Tumorigenesis by the PIK3CAH1047R Oncogene

Single-cell transcriptomics studies have begun to identify breast epithelial cell and stromal cell specific transcriptome differences between BRCA1/2 mutation carriers and non-carriers. We generated a single-cell transcriptome atlas of breast tissues from BRCA1, BRCA2 mutation carriers and compared this single-cell atlas of mutation carriers with our previously described single-cell breast atlas of healthy non-carriers. We observed that BRCA1 but not BRCA2 mutations altered the ratio between basal (basal-myoepithelial), luminal progenitor (luminal adaptive secretory precursor, LASP), and mature luminal (luminal hormone sensing) cells in breast tissues. A unique subcluster of cells within LASP cells is underrepresented in case of BRCA1 and BRCA2 mutation carriers compared with non-carriers. Both BRCA1 and BRCA2 mutations specifically altered transcriptomes in epithelial cells which are an integral part of NFκB, LARP1, and MYC signaling. Signaling pathway alterations in epithelial cells unique to BRCA1 mutations included STAT3, BRD4, SMARCA4, HIF2A/EPAS1, and Inhibin A signaling. BRCA2 mutations were associated with upregulation of IL6, PDK1, FOXO3, and TNFSF11 signaling. These signaling pathway alterations are sufficient to alter sensitivity of BRCA1/BRCA2-mutant breast epithelial cells to transformation as epithelial cells from BRCA1 mutation carriers overexpressing hTERT + PIK3CAH1047R generated adenocarcinomas, whereas similarly modified mutant BRCA2 cells generated basal carcinomas in NSG mice. Thus, our studies provide a high-resolution transcriptome atlas of breast epithelial cells of BRCA1 and BRCA2 mutation carriers and reveal their susceptibility to PIK3CA mutation-driven transformation.

SIGNIFICANCE

This study provides a single-cell atlas of breast tissues of BRCA1/2 mutation carriers and demonstrates that aberrant signaling due to BRCA1/2 mutations is sufficient to initiate breast cancer by mutant PIK3CA.

Curcumin modulates cell type-specific miRNA networks to induce cytotoxicity in ovarian cancer cells

AIM

To understand the epigenetic role of curcumin, a natural polyphenolic compound extracted from the spice Curcuma longa in inducing cytotoxicity in two molecularly distinct ovarian cancer cell lines: PA1 and A2780.

MATERIALS AND METHODS

An integrated mRNA-miRNA sequence analysis was performed to determine the curcumin-induced mRNA-miRNA regulatory networks in the induction of cytotoxicity. The miRNA-mRNA pathways, the miRNAs and their targets implicated in apoptosis, autophagy, DNA damage, and stemness markers were validated. Gene/miRNA expressions were validated using qPCR and protein expressions by western blotting. Curcumin-induced oncogenic /tumor-suppressor miRNAs were profiled utilising the oncomiRdb database. Similarly, the expressions of oncogenes/tumor suppressor genes were profiled and correlated with the TCGA ovarian cancer dataset. A dual luciferase assay was performed to investigate the interaction of miR-199a-5p to its direct target, DDR1.

KEY FINDINGS

The expression of several miRNAs demonstrated an inverse correlation with their respective direct targets. In curcumin-treated PA1 cells, miR-335-5p target ATG5 (autophagic), and OCT4 (pluripotent gene) were downregulated, miR-32a target PTEN (tumor suppressor) was upregulated, miR-1285 target P53 (tumor suppressor) was upregulated, and both miR-182-5p and miR-503-3p target BCL2, were down-regulated. Contrastingly, in curcumin-treated A2780 cells, miR-181a-3p target ATG5, miR-30a-5p, and miR-216a target BECN1 (autophagic) were upregulated, and miR-129a-5p target BCL2 were downregulated. The reversal of the oncomiR/TSmiR profile revealed suppression of oncogenic processes by curcumin. Curcumin treatment induced a moderate cisplatin-sensitisation effect and impaired epithelial-to-mesenchymal transition (EMT) characteristics. Curcumin also regulated the miR-199a-5p/DDR1 axis with a decrease in collagen deposition.

SIGNIFICANCE

The activity of curcumin is cell-type specific. Distinct miRNA regulatory networks were activated to induce multiple modes of cellular cytotoxicity in these ovarian cancer cells. This study further highlights the molecular mechanism of curcumin action in ovarian cancers establishing its candidacy as a promising drug candidate.

Mutant p53 in head and neck squamous cell carcinoma: Molecular mechanism of gain‑of‑function and targeting therapy (Review)

Head and neck squamous cell carcinoma (HNSCC) is one of the most widespread malignancies worldwide. p53, as a transcription factor, can play its role in tumor suppression by activating the expression of numerous target genes. However, p53 is one of the most commonly mutated genes, which frequently harbors missense mutations. These missense mutations are nucleotide substitutions that result in the substitution of an amino acid in the DNA binding domain. Most p53 mutations in HNSCC are missense mutations and the mutation rate of p53 reaches 65‑85%. p53 mutation not only inhibits the tumor suppressive function of p53 but also provides novel functions to facilitate tumor recurrence, called gain‑of‑function (GOF). The present study focused on the prevalence and clinical relevance of p53 mutations in HNSCC, and further described how mutant p53 accumulates. Moreover, mutant p53 in HNSCC can interact with proteins, RNA, and exosomes to exert effects on proliferation, migration, invasion, immunosuppression, and metabolism. Finally, several treatment strategies have been proposed to abolish the tumor‑promoting function of mutant p53; these strategies include reactivation of mutant p53 into wild‑type p53, induction of mutant p53 degradation, enhancement of the synthetic lethality of mutant p53, and treatment with immunotherapy. Due to the high frequency of p53 mutations in HNSCC, a further understanding of the mechanism of mutant p53 may provide potential applications for targeted therapy in patients with HNSCC.

MiRNA-Based Therapies for Lung Cancer: Opportunities and Challenges?

Lung cancer is a commonly diagnosed cancer and the leading cause of cancer-related deaths, posing a serious health risk. Despite new advances in immune checkpoint and targeted therapies in recent years, the prognosis for lung cancer patients, especially those in advanced stages, remains poor. MicroRNAs (miRNAs) have been shown to modulate tumor development at multiple levels, and as such, miRNA mimics and molecules aimed at regulating miRNAs have shown promise in preclinical development. More importantly, miRNA-based therapies can also complement conventional chemoradiotherapy, immunotherapy, and targeted therapies to reverse drug resistance and increase the sensitivity of lung cancer cells. Furthermore, small interfering RNA (siRNA) and miRNA-based therapies have entered clinical trials and have shown favorable development prospects. Therefore, in this paper, we review recent advances in miRNA-based therapies in lung cancer treatment as well as adjuvant therapy and present the current state of clinical lung cancer treatment. We also discuss the challenges facing miRNA-based therapies in the clinical application of lung cancer treatment to provide new ideas for the development of novel lung cancer therapies.

Investigating whether exosomal miR-205-5p derived from tongue squamous cell carcinoma cells stimulates the angiogenic activity of HUVECs by targeting AMOT

BACKGROUND

Although exosomal microRNAs (exo-miRNAs) regulate angiogenesis, they are not sufficient for the development of anti-vascular drugs for tongue squamous cell carcinoma (TSCC). miR-205-5p is an exo-miRNA that is highly expressed in the saliva of patients with oral SCC.

OBJECTIVE

We aimed to clarify the role and molecular mechanism of exosomal miR-205-5p in regulating TSCC angiogenesis.

METHODS

Effect of exosomes derived from TSCC cells on human umbilical vein endothelial cell (HUVEC) function was determined using the CCK-8, Transwell, Transwell-Matrigel, and Matrigel-based tube formation assays. Protein levels were detected by western blot. The binding between miR-205-5p and the 3'UTR of AMOT was verified using a luciferase reporter assay.

RESULTS

Exosomal miR-205-5p (exo-miR-205-5p) promoted the proliferation, migration, and invasion of HUVECs, increased the number of tubes formed by HUVECs, and increased the vascular endothelial growth factor receptor 2 levels in HUVECs. Exo-miR-205-5p downregulated the AMOT level in HUVECs. Results of the luciferase reporter assay showed that miR-205-5p could bind to the 3'UTR of AMOT. AMOT overexpression blocked the effect of exo-miR-205-5p on HUVEC functions.

CONCLUSION

Exo-miR-205-5p derived from TSCC regulates the angiogenic activity of HUVECs by targeting AMOT and might be a new molecular target for the development of anti-vascular drugs for TSCC.

The Long Noncoding Transcript HNSCAT1 Activates KRT80 and Triggers Therapeutic Efficacy in Head and Neck Squamous Cell Carcinoma

Head and neck squamous carcinoma (HNSC) is the most prevalent malignancy of the head and neck regions. Long noncoding RNAs (lncRNAs) are vital in tumorigenesis regulation. However, the role of lncRNAs in HNSC requires further exploration. Herein, through bioinformatic assays using The Cancer Genome Atlas (TCGA) datasets, rapid amplification of cDNA ends (RACE) assays, and RNA-FISH, we revealed that a novel cytoplasmic transcript, HNSC-associated transcript 1 (HNSCAT1, previously recognized as linc01269), was downregulated in tumor samples and advanced tumor stages and was also associated with favorable outcomes in HNSC. Overexpression of HNSCAT1 triggered treatment efficacy in HNSCs both in vivo and in vitro. More importantly, through high-throughput transcriptome analysis (RNA-seq, in NODE database, OEZ007550), we identified KRT80, a tumor suppressor in HNSC, as the target of HNSCAT1. KRT80 expression was modulated by lncRNA HNSCAT1 and presented a positive correlation in tumor samples (R = 0.52, p < 0.001). Intriguingly, we identified that miR-1245 simultaneously interacts with KRT80 and HNSCAT1, which bridges the regulatory function between KRT80 and HNSCAT1. Conclusively, our study demonstrated that lncRNA HNSCAT1 functions as a necessary tumor inhibitor in HNSC, which provides a novel mechanism of lncRNA function and provides alternative targets for the diagnosis and treatment of HNSC.

The Role of MicroRNA in DNA Damage Response

DNA is essential for the development and function of organisms. A number of factors affect DNA integrity and cause DNA damages, such as ultraviolet light, ionizing radiation and hydrogen peroxide. DNA damages activate a series of intracellular reactions, called DNA damage response, which play a crucial role in the pathogenesis of cancers and other diseases. MiRNA is a type of evolutionarily conserved non-coding RNA and affects the expression of target genes by post-transcriptional regulation. Increasing evidences suggested that the expression of some miRNAs was changed in tumor cases. MiRNAs may participate in DNA damage response and affect genomic stability via influencing the processes of cell cycle, DNA damage repair and apoptosis, thus ultimately impact on tumorigenesis. Therefore, the role of miRNA in DNA damage response is reviewed, to provide a theoretical basis for the mechanism of miRNAs' effects on DNA damage response and for the research of new therapies for diseases.

Regulation of miRNAs Expression by Mutant p53 Gain of Function in Cancer

The p53 roles have been largely described; among them, cell proliferation and apoptosis control are some of the best studied and understood. Interestingly, the mutations on the six hotspot sites within the region that encodes the DNA-binding domain of p53 give rise to other very different variants. The particular behavior of these variants led to consider p53 mutants as separate oncogene entities; that is, they do not retain wild type functions but acquire new ones, namely Gain-of-function p53 mutants. Furthermore, recent studies have revealed how p53 mutants regulate gene expression and exert oncogenic effects by unbalancing specific microRNAs (miRNAs) levels that provoke epithelial-mesenchymal transition, chemoresistance, and cell survival, among others. In this review, we discuss recent evidence of the crosstalk between miRNAs and mutants of p53, as well as the consequent cellular processes dysregulated.

LncRNA OTUD6B-AS1 promotes paclitaxel resistance in triple negative breast cancer by regulation of miR-26a-5p/MTDH pathway-mediated autophagy and genomic instability

Genomic instability (GIN) is pivotal in regulating tumor drug resistance, which blocked the treatment of triple negative breast cancer (TNBC). Although recent studies implied that non-coding RNA (ncRNA)-mediated autophagy abolishment promoted tumorigenesis by up-regulation of GIN, autophagy was known as a risk factor in tumor drug resistance. However, previous study also pointed that up-regulation of autophagy promoted GIN. Therefore, the relationship between autophagy and GIN is not clear, and more work is needed. And, if an ncRNA is identified to be a co-regulator of autophagy and GIN, it will be a potential therapy target of chemotherapy resistance in TNBC. In our study, we recognized both autophagy-GIN-associated microRNA (mi-26a-5p) by big data analysis, which was prognosis-correlated in breast cancer. Next, we identified the up-stream regulators (long non-coding RNA, lncRNA) and down-stream targets of miR-26a-5p by bioinformatics analysis (online public databases). Finally, we established lncRNA OTUD6B-AS1/miR-26a-5p/MTDH signaling pathway, and verified their functions by cytological, molecular biological and zoological experiments. In general, our study found (1) miR-26a-5p was a protective factor of breast cancer, while OTUD6B-AS1 and MTDH were risk factors; (2) OTUD6B-AS1 was the up-stream regulator of miR-26a-5p verified by luciferase; (3) up-regulation of miR-26a-5p and down-regulation of MTDH promoted cellular cytotoxicity of paclitaxel (PTX) in vitro and in vivo. (4) down-regulation of miR-26a-5p, overexpression of MTDH and OTUD6B-AS1 promoted autophagy and DNA damage; (5) up-regulation of OTUD6B-AS1 and MTDH inhibited DNA damage response (DDR) by inhibiting the phosphorylated activation of RAD51, ATR and ATM.

miRNA dysregulation is an emerging modulator of genomic instability

Genomic instability consists of a range of genetic alterations within the genome that contributes to tumor heterogeneity and drug resistance. It is a well-established characteristic of most cancer cells. Genome instability induction results from defects in DNA damage surveillance mechanisms, mitotic checkpoints and DNA repair machinery. Accumulation of genetic alterations ultimately sets cells towards malignant transformation. Recent studies suggest that miRNAs are key players in mediating genome instability. miRNAs are a class of small RNAs expressed in most somatic tissues and are part of the epigenome. Importantly, in many cancers, miRNA expression is dysregulated. Consequently, this review examines the role of miRNA dysregulation as a causal step for induction of genome instability and subsequent carcinogenesis. We focus specifically on mechanistic studies assessing miRNA(s) and specific subtypes of genome instability or known modes of genome instability. In addition, we provide insight on the existing knowledge gaps within the field and possible ways to address them.

Footprints of microRNAs in Cancer Biology

MicroRNAs (miRNAs) are short non-coding RNAs involved in post-transcriptional gene regulation. Over the past years, various studies have demonstrated the role of aberrant miRNA expression in the onset of cancer. The mechanisms by which miRNA exerts its cancer-promoting or inhibitory effects are apparent through the various cancer hallmarks, which include selective proliferative advantage, altered stress response, vascularization, invasion and metastasis, metabolic rewiring, the tumor microenvironment and immune modulation; therefore, this review aims to highlight the association between miRNAs and the various cancer hallmarks by dissecting the mechanisms of miRNA regulation in each hallmark separately. It is hoped that the information presented herein will provide further insights regarding the role of cancer and serve as a guideline to evaluate the potential of microRNAs to be utilized as biomarkers and therapeutic targets on a larger scale in cancer research.

MicroRNA-182-5p and microRNA-205-5p as potential biomarkers for prognostic stratification of p16-positive oropharyngeal squamous cell carcinoma

BACKGROUND

MicroRNAs constitute promising biomarkers.

OBJECTIVE

The aim was to investigate diagnostic and prognostic implications of miR-182-5p and miR-205-5p in p16-positive and p16-negative oropharyngeal squamous cell carcinomas (OPSCCs).

METHODS

Expression of miR-182-5p, miR-205-5p were determined via quantitative real-time-PCR in fresh frozen tissues of 26 p16-positive, 19 p16-negative OPSCCs and 18 HPV-negative oropharyngeal controls. Associations between miRNA-expression, clinicopathological characteristics and prognosis were analyzed.

RESULTS

Higher miR-182-5p expression was associated with significant inferior disease-specific survival for p16-positive OPSCCs (HR = 1.98E+09, 95% CI 0-Inf; P= 0.028) and a similar trend was observed for p16-negative OPSCCs (HR = 1.56E+09, 95% CI 0-Inf; P= 0.051). Higher miR-205-5p expression was associated with an inferior progression-free survival (HR = 4.62, 95% CI 0.98-21.83; P= 0.034) and local control rate (HR = 2.18E+09, 95% CI 0-Inf; P= 0.048) for p16-positive OPSCCs.

CONCLUSIONS

Results indicate that miR-182-5p and miR-205-5p can further stratify patients with p16-positive OPSCC into prognostic groups.

HNRNPU-AS1 regulates cell proliferation and apoptosis via miR-205-5p/AXIN2 axis and Wnt/β-catenin signaling pathway in cervical cancer

Long non-coding RNAs (lncRNAs) have key functions in modulating cervical cancer (CC) genesis and progression. This work focused on exploring lncRNA HNRNPU-AS1's function in CC and the underlying mechanism. HNRNPU-AS1, AXIN2 and miR-205-5p levels in CC cases were measured through RT-qPCR. Relationship between miR-205-5p and AXIN2 or HNRNPU-AS1 was validated through dual-luciferase assay. Cell proliferation was examined by CCK-8, while cell apoptosis by colony formation and flow cytometry analysis. HNRNPU-AS1 expression loss could be observed in CC patients and cell lines, which predicted the dismal prognosis of CC cases. Moreover, it was identified that the miR-205-5p level was up-regulated, which acted as an inhibitory target of HNRNPU-AS1 and AXIN2. HNRNPU-AS1 inhibited cell proliferation and promoted apoptosis. As revealed by Kaplan-Meier curve, CC cases showing low HNRNPU-AS1, high miR-205-5p, and low AXIN2 levels had the poorest prognosis. AXIN2 reversed the CC cell proliferation-promoting, apoptosis-inhibiting and Wnt/β-catenin signaling-activating mediated by miR-205-5p or HNRNPU-AS1 knockout. In conclusion, the overexpression of lncRNA HNRNPU-AS1 suppressed CC progression by inhibiting Wnt/β-catenin pathway through miR-205-5p/AXIN2 axis.

MicroRNAs in head and neck squamous cell carcinoma: a possible challenge as biomarkers, determinants for the choice of therapy and targets for personalized molecular therapies

Head and neck squamous cell carcinoma (HNSCC) are referred to a group of heterogeneous cancers that include structures of aerodigestive tract such as oral and nasal cavity, salivary glands, oropharynx, pharynx, larynx, paranasal sinuses, and local lymph nodes. HNSCC is characterized by frequent alterations of several genes such as TP53, PIK3CA, CDKN2A, NOTCH1, and MET as well as copy number increase in EGFR, CCND1, and PIK3CA. These genomic alterations play a role in terms of resistance to chemotherapy, molecular targeted therapy, and prediction of patient outcome. MicroRNAs (miRNAs) are small single-stranded noncoding RNAs which are about 19-25 nucleotides. They are involved in the tumorigenesis of HNSCC including dysregulation of cell survival, proliferation, cellular differentiation, adhesion, and invasion. The discovery of the stable presence of the miRNAs in all human body made them attractive biomarkers for diagnosis and prognosis or as targets for novel therapeutic ways, enabling personalized treatment for HNSCC. In recent times the number of papers concerning the characterization of miRNAs in the HNSCC tumorigenesis has grown a lot. In this review, we discuss the very recent studies on different aspects of miRNA dysregulation with their clinical significance and we apologize for the many past and most recent works that have not been mentioned. We also discuss miRNA-based therapy that are being tested on patients by clinical trials.

MiR-205 Promotes the Viability, Migration, and Tube Formation of Cervical Cancer Cells In Vitro by Targeting GATA3

Background: Both microRNA (miR)-205 and GATA Binding Protein 3 (GATA3) were involved in cervical cancer (CC), yet their correlation remained poorly understood. The authors' study aimed to unveil their correlation in CC. Materials and Methods: Clinical cervical tissue samples were collected. Survival rates of CC patients with high or low miR-205 and GATA3 expressions were analyzed using Kaplan-Meier curve. CC cell viability, migration, and tube formation were measured by cell counting kit-8 assay, scratch assay, and tube formation assay, respectively. The potential binding sites between miR-205 and GATA3 were predicted by TargetScan, and confirmed with dual-luciferase reporter assay. Relative expressions of miR-205, GATA3, vascular endothelial growth factor, E-cadherin, N-cadherin, and vimentin were quantified with quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as needed. Results: MiR-205 was increased, yet GATA3 was decreased in CC, indicating that they were negatively correlated. Upregulating miR-205 increased miR-205 expression and CC cell viability and promoted migration and tube formation, yet decreased GATA3 expression, while downregulating miR-205 exerted the opposite effects. GATA3 was the target gene of miR-205, and reversed the effect of miR-205 on GATA3 expression and cell viability, migration, and tube formation in CC cells by reversing the effects of miR-205 on migration- and tube formation-related protein expressions. Conclusion: MiR-205 promotes CC cell viability, migration, and tube formation in vitro by targeting GATA3, providing new evidence for the implication of miR-205 in CC and a possible therapeutic method for CC. Clinical Trial Registration number: ZLK-20181103-01.

The i-Motif as a Molecular Target: More Than a Complementary DNA Secondary Structure

Stretches of cytosine-rich DNA are capable of adopting a dynamic secondary structure, the i-motif. When within promoter regions, the i-motif has the potential to act as a molecular switch for controlling gene expression. However, i-motif structures in genomic areas of repetitive nucleotide sequences may play a role in facilitating or hindering expansion of these DNA elements. Despite research on the i-motif trailing behind the complementary G-quadruplex structure, recent discoveries including the identification of a specific i-motif antibody are pushing this field forward. This perspective reviews initial and current work characterizing the i-motif and providing insight into the biological function of this DNA structure, with a focus on how the i-motif can serve as a molecular target for developing new therapeutic approaches to modulate gene expression and extension of repetitive DNA.

The cross-talk between signaling pathways, noncoding RNAs and DNA damage response: Emerging players in cancer progression

The DNA damage response (DDR) pathway's primary purpose is to maintain the genome structure's integrity and stability. A great deal of effort has done to understand the exact molecular mechanisms of non-coding RNAs, such as lncRNA, miRNAs, and circRNAs, in distinct cellular and genomic processes and cancer progression. In this regard, the ncRNAs possible regulatory role in DDR via modulation of key components expression and controlling repair signaling pathway activation is validated. Therefore, in this article, we will discuss the latest developments of ncRNAs contribution in different aspects of DNA repair through regulation of ATM-ATR, P53, and other regulatory signaling pathways.

Clinical significance and potential mechanisms of miR-223-3p and miR-204-5p in squamous cell carcinoma of head and neck: a study based on TCGA and GEO

Objective

To explore the clinical significance and mechanisms of altered miRNAs in squamous cell carcinoma of head and neck (SCCHN) and provide references for SCCHN diagnosis and prognosis.

Method

Differential expressed miRNAs (DEMs) in SCCHN were screened through gene expression omnibus (GEO) DataSets and verified by the cancer genome atlas (TCGA) database. Next, the overall survival analysis, receiver operating characteristics, and clinical correlation analysis were adopted to filter the miRNAs with diagnostic and prognostic values. Finally, functional enrichment analyses were conducted for inquiring into the mechanisms of miRNAs.

Results

Total 103 DEMs (p < 0.05, fold change ≥ 2) in SCCHN were screened out from GSE124566. Partly, the expression levels of the selected (12/17) miRNAs were verified by TCGA. Followed, of the 12 miRNAs, two miRNA expression levels were associated with the overall survival, and five miRNAs showed diagnostic values (AUC ≥ 0.85). Besides, miR-223-3p and miR-204-5p expression levels were correlated to certain clinical features. Epithelial–mesenchymal transition (EMT) related biological process and energy metabolism controlling related AMPK signaling pathway might mediate the roles of miR-223-3p and miR-204-5p, respectively.

Conclusion

With diagnostic and prognostic values, miR-223-3p and miR-204-5p may be involved in the progression of SCCHN through EMT-related biological process and energy balance related AMPK signaling pathway, respectively.

microRNAs deregulation in head and neck squamous cell carcinoma

Head and neck (HN) squamous cell carcinoma (SCC) is the eighth most common human cancer worldwide. Besides tobacco and alcohol consumption, genetic and epigenetic alterations play an important role in HNSCC occurrence and progression. microRNAs (miRNAs) are small noncoding RNAs that regulate cell cycle, proliferation, development, differentiation, and apoptosis by interfering in gene expression. Expression profiling of miRNAs showed that some miRNAs are upregulated or downregulated in tumor cells when compared with the normal cells. The present review focuses on the role of miRNAs deregulations in HNSCC, enrolled in risk, development, outcome, and therapy sensitivity. Moreover, the influence of single nucleotide variants in miRNAs target sites, miRNAs seed sites, and miRNAs-processing genes in HNSCC was also revised. Due to its potential for cancer diagnosis, progression, and as a therapeutic target, miRNAs may bring new perspectives in HNSCC understanding and therapy, especially for those patients with no or insufficient treatment options.

Epigenetic regulation of VENTXP1 suppresses tumor proliferation via miR-205-5p/ANKRD2/NF-kB signaling in head and neck squamous cell carcinoma

An increasing number of studies have shown that long noncoding RNAs (lncRNAs) play important roles in tumor development and progression. However, their involvement in head and neck squamous cell carcinoma (HNSCC) remains largely unknown. Epigenetic regulation is one major mechanism utilized by cancer cells to control lncRNA expression. We identified that lncRNA VENTXP1 was epigenetically silenced in multiple cancer types, and its lower expression was correlated with poorer survival in HNSCC patients. Through in silico analysis and experimental validation, we identified miR-205-5p and its direct interacting partner of VENTXP1, which regulates HNSCC cell proliferation and tumorigenicity. Using RNA-seq and differential gene expression analysis, we further identified ANKRD2 as a miR-205-5p target, which plays an essential role in modulating NF-kB signaling. These findings suggest that VENTXP1 inhibits tumor growth via suppressing miR-205-5p/ANKRD2-mediated NF-kB signaling in HNSCC. Thus, pharmaceutical targeting of DNA methylation to restore VENTXP1 expression might constitute a therapeutic strategy for HNSCC.

Comprehensive analysis of the expression and prognosis for CDCAs in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC), a tumor included oral cavity, lips, larynx, oropharynx, and the nasopharynx et al. The cell division cycle-associated (CDCA) protein family (CDCA1-8) critical for normal cell function and cancer cell proliferation. We explored the mutation signatures and expression levels of various CDCAs in detail in HNSCC. A comprehensive bioinformatics analysis pipeline based on copy number and gene expressions data from patients with HNSCC in order to given new insights into the possible functions and distinct prognostics that underlie CDCAs regulation. We compared the transcriptional expression of CDCAs in HNSCC and found significantly elevated mRNA expression of CDCA1-8 in HNSCC tissues across multiple datasets. We also found CDCA5/6/8 are over-expressed both transcriptionally and translationally in patients with HNSCC. Our results suggested that that mRNA levels of CDCA1/2/4/7 related to the prognosis and can be used as a new useful biomarker for predicting the survival of HNSCC patients. The top 5 CDCAs neighboring gene alterations in HNSCCs were found in MYC, STAG1, RAD21, KLHL9 and NDC80. Multivariable Cox proportional hazard model also showed that CD8+ T cells were higher (P<0.05) in HNSCC-HPV-pos patients and that this was related to CDCA1/2/3/4/5/7. This study utilizes online tools to conduct specific gene analyses from free open databases, but our study requires more large-scale genomics research and basic research.

A miR-205-LPCAT1 axis contributes to proliferation and progression in multiple cancers

In the past two decades, miRNAs have been demonstrated to play critical roles in development and progression of malignant diseases. To identify the role and mechanism of miRNA are urgent for the application of miRNA-based therapeutics in cancers. MiR-205 is a conserved miRNA from the invertebrate to mammalian species. Previous studies showed a large body of evidence to demonstrate the oncogenic or tumor suppressive role of it in different types of cancers. Our aim here is to clarify the role and novel mechanism of miR-205 in solid tumors. In the present study, we found that a high level of miR-205 is an independent biomarker for favorable prognosis in LIHC, HNSCC and LUSC. In the functional experiment, we stably expressed miR-205 in tumor cell lines derived from above mentioned cancers. The result showed that overexpression of miR-205 significantly inhibits cancer cell proliferation. Mechanistically, we identified that the lysophosphatidylcholine acyltransferase-1 (LPCAT1) is a novel target of miR-205 in multiple cancer cells. Furthermore, we found that LPCAT1 is required for sustained proliferation of cancer cells and a high level of it is closely associated with poor prognosis in clinical patients. Collectively, we revealed the important prognostic value of a miR-205-LPCAT1 axis in multiple cancers and highlighted an essential role of LPCAT1 in miR-205-regulated cancer cell proliferation. All these discoveries make a miR-205-LPCAT1 axis to shed light upon a potential therapeutic target in cancer treatment.

The Impact of Mutant p53 in the Non-Coding RNA World

Long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), micro RNAs (miRNAs), and extracellular RNAs (exRNAs) are new groups of RNAs with regulation activities that have low or no protein-coding ability. Emerging evidence suggests that deregulated expression of these non-coding RNAs is associated with the induction and progression of diverse tumors throughout epigenetic, transcriptional, and post-transcriptional modifications. A consistent number of non-coding RNAs (ncRNAs) has been shown to be regulated by p53, the most important tumor suppressor of the cells frequently mutated in human cancer. It has been shown that some mutant p53 proteins are associated with the loss of tumor suppressor activity and the acquisition of new oncogenic functions named gain-of-function activities. In this review, we highlight recent lines of evidence suggesting that mutant p53 is involved in the expression of specific ncRNAs to gain oncogenic functions through the creation of a complex network of pathways that influence each other.

Role of telomerase in the tumour microenvironment

Telomeres are specialized genomic structures that protect chromosomal ends to maintain genomic stability. Telomeric length is primarily regulated by the telomerase complex, essentially consisting of an RNA template (TERC), an enzymatic subunit (telomerase reverse transcriptase, TERT). In humans, telomerase activity is repressed during embryonic differentiation and is absent in most somatic cells. However, it is upregulated or reactivated in 80%-90% of the primary tumours in humans. The human TERT (hTERT) plays a pivotal role in cellular immortality and tumourigenesis. However, the molecular mechanisms of telomerase functioning in cancer have not been fully understood beyond the telomere maintenance. Several research groups, including ours, have demonstrated that hTERT possesses vital functions independent of its telomere maintenance, including angiogenesis, inflammation, cancer cell stemness, and epithelial-mesenchymal transformation (EMT). All these telomere-independent activities of hTERT may contribute to the regulation of the dynamics and homeostasis of the tumour microenvironment (TME), thereby promoting tumour growth and development. Cancer progression and metastasis largely depend upon the interactions between cancer cells and their microenvironment. In this review, the involvement of TERT in the tumour microenvironment and the underlying implications in cancer therapeutics have been summarized.

Epigenetic Modifications in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common human malignancy in the world, with high mortality and poor prognosis for patients. Among the risk factors are tobacco and alcohol intake, human papilloma virus, and also genetic and epigenetic modifications. Many studies show that epigenetic events play an important role in HNSCC development and progression, including DNA methylation, chromatin remodeling, histone posttranslational covalent modifications, and effects of non-coding RNA. Epigenetic modifications may influence silencing of tumor suppressor genes by promoter hypermethylation, regulate transcription by microRNAs and changes in chromatin structure, or induce genome instability through hypomethylation. Moreover, getting to better understand aberrant patterns of methylation may provide biomarkers for early detection and diagnosis, while knowledge about target genes of microRNAs may improve the therapy of HNSCC and extend overall survival. The aim of this review is to present recent studies which demonstrate the role of epigenetic regulation in the development of HNSCC.