Small extracellular vesicle-packaged TGFβ1 promotes the reprogramming of normal fibroblasts into cancer-associated fibroblasts by regulating fibronectin in head and neck squamous cell carcinoma

Exosome nanovesicles: biomarkers and new strategies for treatment of human diseases

Exosomes are nanoscale vesicles of cellular origin. One of the main characteristics of exosomes is their ability to carry a wide range of biomolecules from their parental cells, which are important mediators of intercellular communication and play an important role in physiological and pathological processes. Exosomes have the advantages of biocompatibility, low immunogenicity, and wide biodistribution. As researchers' understanding of exosomes has increased, various strategies have been proposed for their use in diagnosing and treating diseases. Here, we provide an overview of the biogenesis and composition of exosomes, describe the relationship between exosomes and disease progression, and focus on the use of exosomes as biomarkers for early screening, disease monitoring, and guiding therapy in refractory diseases such as tumors and neurodegenerative diseases. We also summarize the current applications of exosomes, especially engineered exosomes, for efficient drug delivery, targeted therapies, gene therapies, and immune vaccines. Finally, the current challenges and potential research directions for the clinical application of exosomes are also discussed. In conclusion, exosomes, as an emerging molecule that can be used in the diagnosis and treatment of diseases, combined with multidisciplinary innovative solutions, will play an important role in clinical applications.

Prognostic significance and immune escape implication of tumor-infiltrating neutrophil plasticity in human head and neck squamous cell carcinoma

Tumor-infiltrating neutrophils play a crucial role in the progression of head and neck squamous cell carcinoma (HNSCC). Here, we aimed to statistically quantify the plasticity of HNSCC-infiltrating N2/N1 neutrophils and examine its impacts on survival and immune infiltration landscape. A retrospective study of 80 patients who underwent curative surgical resection for HNSCC between 2014 and 2017 was conducted in this study. HNSCC-infiltrating neutrophil phenotypes were classified using immunofluorescence staining, and the N2/N1 neutrophil plasticity was evaluated via the ratio of N2/N1 neutrophils. We then assessed the correlations between N2/N1 neutrophil plasticity, clinicopathological characteristics, and immune infiltration landscape using rigorous statistical methods. Infiltration variations of N1 and N2 neutrophils were observed between the tumor nest (TN) and tumor stroma (TS), with TN exhibiting higher N2 neutrophil infiltration and lower N1 neutrophil infiltration. High ratios of N2/N1 neutrophils were correlated with advanced TNM stage, large tumor size and invasion of adjacent tissue. High infiltration of N2 neutrophils was associated with decreased overall and relapse-free survival, which were opposite for N1 neutrophils. The independent prognostic role of N2/N1 neutrophil plasticity, particularly within the TN region, was confirmed by multivariate analyses. Moreover, the ratio of N2/N1 neutrophils within the TN region showed correlations with high CD8+ T cells infiltration and low FOXP3+ Tregs infiltration. We identify HNSCC-infiltrating N2/N1 neutrophil plasticity as a crucial prognostic indictor which potentially reflects the tumor microenvironment (TME) and immune escape landscape within HNSCC tissues. Further investigations and validations may provide novel therapeutic strategies for personalized immunomodulation in HNSCC patients.

Exploring Tumor-Promoting Qualities of Cancer-Associated Fibroblasts and Innovative Drug Discovery Strategies With Emphasis on Thymoquinone

Tumor epithelial development and chemoresistance are highly promoted by the tumor microenvironment (TME), which is mostly made up of the cancer stroma. This is due to several causes. Cancer-associated fibroblasts (CAFs) stand out among them as being essential for the promotion of tumors. Understanding the fibroblastic population within a single tumor is made more challenging by the undeniable heterogeneity within it, even though particular stromal alterations are still up for debate. Numerous chemical signals released by tumors improve the connections between heterotypic fibroblasts and CAFs, promoting the spread of cancer. It becomes essential to have a thorough understanding of this complex microenvironment to effectively prevent solid tumor growth. Important new insights into the role of CAFs in the TME have been revealed by recent studies. The objective of this review is to carefully investigate the relationship between CAFs in tumors and plant secondary metabolites, with a focus on thymoquinone (TQ). The literature published between 2010 and 2023 was searched in PubMed and Google Scholar with keywords such as TQ, TME, cancer-associated fibroblasts, mechanism of action, and flavonoids. The results showed a wealth of data substantiating the activity of plant secondary metabolites, particularly TQ's involvement in blocking CAF operations. Scrutinized research also clarified the wider effect of flavonoids on pathways related to cancer. The present study highlights the complex dynamics of the TME and emphasizes the critical role of CAFs. It also examines the possible interventions provided by secondary metabolites found in plants, with TQ playing a vital role in regulating CAF function based on recent literature.

The Role of Inflammation-Associated Factors in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC), which originates in the head or neck tissues, is characterized by high rates of recurrence and metastasis. Inflammation is important in HNSCC prognosis. Inflammatory cells and their secreted factors contribute to the various stages of HNSCC development through multiple mechanisms. In this review, the mechanisms through which inflammatory factors, signaling pathways, and cells contribute to the initiation and progression of HNSCC have been discussed in detail. Furthermore, the diagnostic and therapeutic potential of targeting inflammation in HNSCC has been discussed to gain new insights into improving patient prognosis.

Transcutaneous carbon dioxide application suppresses the expression of cancer-associated fibroblasts markers in oral squamous cell carcinoma xenograft mouse model

Oral squamous cell carcinoma (OSCC) is the most common head and neck cancer. Cancer-associated fibroblasts (CAFs) are the main stromal cells in the tumor microenvironment (TME). As CAFs promote tumor progression and hypoxia in the TME, regulating the conversion of normal fibroblasts (NFs) into CAFs is essential for improving the prognosis of patients with OSCC. We have previously reported the antitumor effects of transcutaneous carbon dioxide (CO2) application in OSCC. However, the effects of reducing hypoxia in the TME remain unclear. In this study, we investigated whether CO2 administration improves the TME by evaluating CAFs marker expression. Human OSCC cells (HSC-3) and normal human dermal fibroblasts (NHDF) were coinjected subcutaneously into the dorsal region of mice. CO2 gas was applied twice a week for 3 weeks. The tumors were harvested six times after transcutaneous CO2 application. The expression of CAFs markers (α-SMA, FAP, PDPN, and TGF-β) were evaluated by using real-time polymerase chain reaction and immunohistochemical staining. The expression of α-SMA, FAP, PDPN, and TGF-β was significantly increased over time after co-injection. In the CO2-treated group, tumor growth was significantly suppressed after treatment initiation. In addition, the mRNA expression of these markers was significantly inhibited. Furthermore, immunohistochemical staining revealed a significant decrease in the protein expression of all CAFs markers in the CO2-treated group. We confirmed that transcutaneous CO2 application suppressed CAFs marker expression and tumor growth in OSCC xenograft mouse model.

Tetraspanin CD63 reduces the progression and metastasis of head and neck squamous cell carcinoma via KRT1-mediated cell cycle arrest

Despite the fact that metastasis is the leading cause of death in patients with head and neck squamous cell carcinoma, fundamental questions about the mechanisms that enable or inhibit metastasis remain unanswered. Tetraspanin CD63 has been linked to tumor progression and metastasis. However, few studies have examined the role of CD63 in HNSCC. In this study, we discovered that CD63 levels were abnormally altered in HNSCC tissue compared to adjacent tissue (n = 69 pairs), and that this was linked to prognosis. Through functional in vitro and in vivo experiments, the roles of CD63 in HNSCC were confirmed. Overexpression of CD63 inhibited the progression and metastasis of HNSCC cells. Using mass spectrometry and co-immunoprecipitation assays, we discovered that KRT1 could be a direct interacting partner of CD63. Furthermore, both CD63 and KRT1 expression was significantly decreased in metastatic tissue compared with primary tumor tissue (n = 13 pairs), suggesting that CD63 and KRT1 play a role in reducing the metastasis of HNSCC. In summary, we reveal a previously unrecognized role of CD63 in regulating KRT1-mediated cell cycle arrest in HNSCC cells, and our findings contribute to defining an important mechanism of HNSCC progression and metastasis.

A decellularized lung extracellular matrix/chondroitin sulfate/gelatin/chitosan-based 3D culture system shapes breast cancer lung metastasis

Distal metastasis of breast cancer is a primary cause of death, and the lung is a common metastatic target of breast cancer. However, the role of the lung niche in promoting breast cancer progression is not well understood. Engineered three-dimensional (3D) in vitro models capable of bridging this knowledge gap can be specifically designed to mimic crucial characteristics of the lung niche in a more physiologically relevant context than conventional two-dimensional systems. In this study, two 3D culture systems were developed to mimic the late stage of breast cancer progression at a lung metastatic site. These 3D models were created based on a novel decellularized lung extracellular matrix/chondroitin sulfate/gelatin/chitosan composite material and on a porcine decellularized lung matrix (PDLM), with the former tailored with comparable properties (stiffness, pore size, biochemical composition, and microstructure) to that of the in vivo lung matrix. The different microstructure and stiffness of the two types of scaffolds yielded diverse presentations of MCF-7 cells in terms of cell distribution, cell morphology, and migration. Cells showed better extensions with apparent pseudopods and more homogeneous and reduced migration activity on the composite scaffold compared to those on the PDLM scaffold. Furthermore, alveolar-like structures with superior porous connectivity in the composite scaffold remarkably promoted aggressive cell proliferation and viability. In conclusion, a novel lung matrix-mimetic 3D in vitro breast cancer lung metastasis model was developed to clarify the underlying correlativity between lung ECM and breast cancer cells after lung colonization. A better understanding of the effects of biochemical and biophysical environments of the lung matrix on cell behaviors can help elucidate the potential mechanisms of breast cancer progression and further improve target discovery of therapeutic strategies.

Proteomic Research of Extracellular Vesicles in Clinical Biofluid

Extracellular vesicles (EVs), the lipid bilayer membranous structures of particles, are produced and released from almost all cells, including eukaryotes and prokaryotes. The versatility of EVs has been investigated in various pathologies, including development, coagulation, inflammation, immune response modulation, and cell-cell communication. Proteomics technologies have revolutionized EV studies by enabling high-throughput analysis of their biomolecules to deliver comprehensive identification and quantification with rich structural information (PTMs, proteoforms). Extensive research has highlighted variations in EV cargo depending on vesicle size, origin, disease, and other features. This fact has sparked activities to use EVs for diagnosis and treatment to ultimately achieve clinical translation with recent endeavors summarized and critically reviewed in this publication. Notably, successful application and translation require a constant improvement of methods for sample preparation and analysis and their standardization, both of which are areas of active research. This review summarizes the characteristics, isolation, and identification approaches for EVs and the recent advances in EVs for clinical biofluid analysis to gain novel knowledge by employing proteomics. In addition, the current and predicted future challenges and technical barriers are also reviewed and discussed.

Heterogeneity of cancer-associated fibroblasts in head and neck squamous cell carcinoma: opportunities and challenges

Head and neck squamous cell carcinoma (HNSCC) is among the most severe and complex malignant diseases with a high level of heterogeneity and, as a result, a wide range of therapeutic responses, regardless of clinical stage. Tumor progression depends on ongoing co-evolution and cross-talk with the tumor microenvironment (TME). In particular, cancer-associated fibroblasts (CAFs), embedded in the extracellular matrix (ECM), induce tumor growth and survival by interacting with tumor cells. Origin of CAFs is quite varied, and the activation patterns of CAFs are also heterogeneous. Crucially, the heterogeneity of CAFs appears to play a key role in ongoing tumor expansion, including facilitating proliferation, enhancing angiogenesis and invasion, and promoting therapy resistance, through the production of cytokines, chemokines, and other tumor-promotive molecules in the TME. This review describes the various origin and heterogeneous activation mechanisms of CAFs, and biological heterogeneity of CAFs in HNSCC is also included. Moreover, we have highlighted versatility of CAFs heterogeneity in HNSCC progression, and have discussed different tumor-promotive functions of CAFs respectively. In the future, it is a promising strategy for the therapy of HNSCC that specifically targeting tumor-promoting CAF subsets or the tumor-promoting functional targets of CAFs.

Fibroblasts as Turned Agents in Cancer Progression

Differentiated epithelial cells reside in the homeostatic microenvironment of the native organ stroma. The stroma supports their normal function, their G0 differentiated state, and their expansion/contraction through the various stages of the life cycle and physiologic functions of the host. When malignant transformation begins, the microenvironment tries to suppress and eliminate the transformed cells, while cancer cells, in turn, try to resist these suppressive efforts. The tumor microenvironment encompasses a large variety of cell types recruited by the tumor to perform different functions, among which fibroblasts are the most abundant. The dynamics of the mutual relationship change as the sides undertake an epic battle for control of the other. In the process, the cancer "wounds" the microenvironment through a variety of mechanisms and attracts distant mesenchymal stem cells to change their function from one attempting to suppress the cancer, to one that supports its growth, survival, and metastasis. Analogous reciprocal interactions occur as well between disseminated cancer cells and the metastatic microenvironment, where the microenvironment attempts to eliminate cancer cells or suppress their proliferation. However, the altered microenvironmental cells acquire novel characteristics that support malignant progression. Investigations have attempted to use these traits as targets of novel therapeutic approaches.

Signaling pathways in cancer-associated fibroblasts: recent advances and future perspectives

As a critical component of the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) play important roles in cancer initiation and progression. Well-known signaling pathways, including the transforming growth factor-β (TGF-β), Hedgehog (Hh), Notch, Wnt, Hippo, nuclear factor kappa-B (NF-κB), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), mitogen-activated protein kinase (MAPK), and phosphoinositide 3-kinase (PI3K)/AKT pathways, as well as transcription factors, including hypoxia-inducible factor (HIF), heat shock transcription factor 1 (HSF1), P53, Snail, and Twist, constitute complex regulatory networks in the TME to modulate the formation, activation, heterogeneity, metabolic characteristics and malignant phenotype of CAFs. Activated CAFs remodel the TME and influence the malignant biological processes of cancer cells by altering the transcriptional and secretory characteristics, and this modulation partially depends on the regulation of signaling cascades. The results of preclinical and clinical trials indicated that therapies targeting signaling pathways in CAFs demonstrated promising efficacy but were also accompanied by some failures (e.g., NCT01130142 and NCT01064622). Hence, a comprehensive understanding of the signaling cascades in CAFs might help us better understand the roles of CAFs and the TME in cancer progression and may facilitate the development of more efficient and safer stroma-targeted cancer therapies. Here, we review recent advances in studies of signaling pathways in CAFs and briefly discuss some future perspectives on CAF research.

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via extracellular vesicles

Intercellular communication plays an important role in cancer initiation and progression through direct contact and indirect interactions, such as via secretory molecules. Cancer-associated fibroblasts (CAFs) are one of the principal components of such communication with cancer cells, modulating cancer metastasis and tumour mechanics and influencing angiogenesis, the immune system, and therapeutic resistance. Over the past few years, there has been a significant increase in research on extracellular vesicles (EVs) as regulatory agents in intercellular communication. EVs enable the transfer of functional molecules, including proteins, mRNAs and microRNAs (miRNAs), to recipient cells. Cancer cells utilize EVs to dictate the specific characteristics of CAFs within the tumour microenvironment, thereby promoting cancer progression. In response to such "education" by cancer cells, CAFs contribute to cancer progression via EVs. In this review, we summarize experimental data indicating the pivotal roles of EVs in intercellular communication between cancer cells and CAFs.

ATP Promotes Oral Squamous Cell Carcinoma Cell Invasion and Migration by Activating the PI3K/AKT Pathway via the P2Y2-Src-EGFR Axis

Oral cancer is one of the most common malignancies of the head and neck, and approximately 90% of oral cancers are oral squamous cell carcinomas (OSCCs). The purinergic P2Y2 receptor is upregulated in breast cancer, pancreatic cancer, colorectal cancer, and liver cancer, but its role in OSCC is still unclear. Here, we examined the effects of P2Y2 on the invasion and migration of oral cancer cells (SCC15 and CAL27). The BALB/c mouse model was used to observe the involvement of P2Y2 with tumors in vivo. P2Y2, Src, and EGFR are highly expressed in OSCC tissues and cell lines. Stimulation with ATP significantly enhanced cell invasion and migration in oral cancer cells, and enhanced the activity of Src and EGFR protein kinases, which is mediated by the PI3K/AKT signaling pathway. P2Y2 knockdown attenuated the above ATP-driven events in vitro and in vivo. The PI3K/AKT signaling pathway was blocked by Src or EGFR inhibitor. Extracellular ATP activates the PI3K/AKT pathway through the P2Y2-Src-EGFR axis to promote OSCC invasion and migration, and thus, P2Y2 may be a potential novel target for antimetastasis therapy.

Plasma Extracellular Vesicles-Derived miR-99a-5p: A Potential Biomarker to Predict Early Head and Neck Squamous Cell Carcinoma

Purpose: This study aimed to investigate the applicability of plasma extracellular vesicles (EVs) miR-99a-5p as a potential head and neck squamous cell carcinoma (HNSCC) diagnostic biomarker.

Methods: The miRNA expression of HNSCC tissue and plasma EVs were profiled by small RNA sequencing. qRT-PCR was performed to detect miR-99a-5p expression in HNSCC (n = 93) and benign disease (n = 39) plasma EVs and formalin-fixed and paraffin-embedded (FFPE) tissue (n = 110). We constructed receiver-operating characteristic curves to investigate the diagnostic efficiency of plasma EVs miR-99a-5p.

Results: Tumor tissue exhibited lower miR-99a-5p than para-tumor tissue. Patients with high miR-99a-5p expression exhibited significantly more p16 positive status. In contrast, HNSCC plasma EVs harbored more miR-99a-5p than the benign disease group. Plasma EVs miR-99a-5p distinguished HNSCC with area under the curve (AUC) of 0.7494 (95% CI: 0.6692–0.8296; p < 0.0001), with 61.54% sensitivity and 75.27% specificity, respectively. Furthermore, plasma EVs miR-99a-5p also distinguished early HNSCC with AUC of 0.7394 (95% CI: 0.6284–0.8504; p = 0.0002), with 79.07% sensitivity and 61.54% specificity, respectively.

Conclusion: Plasma EVs miR-99a-5p is a potential biomarker for predicting early HNSCC.

Exosomes and cancer - Diagnostic and prognostic biomarkers and therapeutic vehicle

Exosomes belong to a subpopulation of extracellular vesicles secreted by the dynamic multistep endocytosis process and carry diverse functional molecular cargoes, including proteins, lipids, nucleic acids (DNA, messenger and noncoding RNA), and metabolites to promote intercellular communication. Proteins and noncoding RNA are among the most abundant contents in exosomes; they have biological functions and are selectively packaged into exosomes. Exosomes derived from tumor, stromal and immune cells contribute to the multiple stages of cancer progression as well as resistance to therapy. In this review, we will discuss the biogenesis of exosomes and their roles in cancer development. Since specific contents within exosomes originate from their cells of origin, this property allows exosomes to function as valuable biomarkers. We will also discuss the potential use of exosomes as diagnostic and prognostic biomarkers or predictors for different therapeutic strategies for multiple cancers. Furthermore, the applications of exosomes as direct therapeutic targets or engineered vehicles for drugs are an important field of exosome study. Better understanding of exosome biology may pave the way to promising exosome-based clinical applications.

Fusobacterium nucleatum impairs DNA mismatch repair and stability in patients with squamous cell carcinoma of the head and neck

BACKGROUND

Dysbiosis of the laryngeal microbiota has been demonstrated to the development of head and neck squamous cell carcinoma (HNSCC), but the association of Fusobacterium and Fusobacterium nucleatum (F. nucleatum) with DNA mismatch repair (MMR) and microsatellite instability (MSI) has not been investigated.

METHODS

The abundance of Fusobacterium and F. nucleatum, the status of deficient MMR (dMMR) and MSI, and MMR-related gene expression were analyzed in 171 HNSCC tissues, 61 paired para-tumor tissues, and 60 vocal cord polyp tissues. The molecular mechanism of F. nucleatum and MMR-related gene expression were investigated in two human HNSCC cell lines (Tu 686 and FD-LSC-1).

RESULTS

Our results demonstrated that a high Fusobacterium abundance was detected in the HNSCC tissues and was exaggerated in the recurrent patients. We further found that a high Fusobacterium abundance was detected in the HNSCC tissues with dMMR and MSI. The Fusobacterium abundance was negatively correlated with the expression of MLH1, MSH2, and MSH6 in the HNSCC tissues. The Fusobacterium abundance was closely associated with the F. nucleatum abundance in the HNSCC tissues. F. nucleatum increased miR-205-5p expression to suppress MLH1, MSH2, and MSH6 expression via the TLR4- and MYD88-dependent innate immune signaling pathway, resulting in dMMR, DNA damage, and cell proliferation in HNSCC.

CONCLUSIONS

F. nucleatum impacts HNSCC epigenetic changes in tissues with dMMR to promote DNA damage and cell proliferation by suppressing MMR-related gene expression via the TLR4/MYD88/miR-205-5p signaling pathway, which is valuable in the development of efficient strategies for HNSCC prevention and treatment.

LAY SUMMARY

This study clearly indicates that Fusobacterium induced head and neck squamous cell carcinoma (HNSCC) aggressiveness to affect poor prognosis in HNSCC patients by epigenetic alteration of DNA mismatch repair (MMR) and microsatellite instability. Moreover, the research has shown that Fusobacterium nucleatum ( F. nucleatum ) impacts HNSCC epigenetic changes in tissues with deficient MMR to promote DNA damage and cell proliferation by suppressing MMRrelated gene expression via the TLR4/MYD88/miR-205-5p signaling pathway.

The Regulation of Lymph Node Pre-Metastatic Niche Formation in Head and Neck Squamous Cell Carcinoma

In many distinct forms of malignancies, there is a close relationship between lymph node (LN) metastases and further dissemination to distant organs, and this is a critical prognostic factor. At the beginning of the process, the original tumor secretes soluble substances or releases extracellular vesicles (EVs) that are carried through lymphatic channels to draining (sentinel) LN. The tumor-derived factors then drive LN remodeling. These significant alterations occur prior to the emergence of the first metastatic cell, bringing about the development of a pre-metastatic niche that allows metastatic cells to survive and thrive. In this review, we discuss current information available about the regulation of lymph node pre-metastatic niche in head and neck squamous cell carcinoma (HNSCC), and the role of EVs in forming the pre-metastatic niche.

Cancer-Associated Fibroblasts Influence the Biological Properties of Malignant Tumours via Paracrine Secretion and Exosome Production

Cancer-associated fibroblasts (CAFs) are an essential component of the tumour microenvironment. They represent a heterogeneous group of cells that are under the control of cancer cells and can reversely influence the cancer cell population. They affect the cancer cell differentiation status, and the migration and formation of metastases. This is achieved through the production of the extracellular matrix and numerous bioactive factors. IL-6 seems to play the central role in the communication of noncancerous and cancer cells in the tumour. This review outlines the role of exosomes in cancer cells and cancer-associated fibroblasts. Available data on the exosomal cargo, which can significantly intensify interactions in the tumour, are summarised. The role of exosomes as mediators of the dialogue between cancer cells and cancer-associated fibroblasts is discussed together with their therapeutic relevance. The functional unity of the paracrine- and exosome-mediated communication of cancer cells with the tumour microenvironment represented by CAFs is worthy of attention.

Identifying KRT20 as a Potential Key Gene in Lymphatic Metastasis of Head and Neck Squamous Cell Carcinoma

Background: Head and neck squamous cell carcinoma (HNSCC) was the seventh most common cancer worldwide in 2018. Lymphatic metastasis (LM) is closely related to HNSCC prognosis and recurrence. However, the underlying mechanism of LM remains unclear. Therefore, this study aimed to identify the key genes in the LM of HNSCC. Methods: We used The Cancer Genome Atlas (TCGA) to identify differentially expressed genes (DEGs) between LM and non-LM cases. A random forest model, the Search Tool for the Retrieval of Interacting Genes, Cytoscape, and cytoHubba were used to identify hub genes among DEGs, including KRT20 (Cytokeratins 20). We analyzed the survival of KRT20 in TCGA, and we overexpressed KRT20 in HNSCC cell lines to investigate its effects on migration and invasion. We also correlated the expression of KRT20 in HNSCC tissue microarrays with survival and clinicopathological features. Results: We identified 243 DEGs—143 upregulated genes and 100 downregulated genes. Further analysis revealed that KRT20 is a potential key gene associated with LM and overall survival rates among patients with HNSCC. Overexpression of KRT20 increased the migration and invasion ability of HNSCC cell lines Tu686 and FD-LSC-1. Tissue microarray studies demonstrated an overexpression of KRT20 among N1+ patients (including N1-N3 patients). Survival analysis results and the clinicopathological features of HNSCC tissue microarrays were consistent with our analysis of TCGA. Thus, a high KRT20 expression level might suggest an adverse HNSCC prognosis. Our gene set enrichment analysis showed that KRT20 participates in many metabolic pathways, including those related to tumorigenesis and cancer development. Conclusions: We propose that KRT20 may be a key gene in HNSCC with LM.

Pan-Cancer Analysis of the N6-Methyladenosine Eraser FTO as a Potential Prognostic and Immunological Biomarker

Background

Fat mass and obesity-associated protein (FTO) is a critical N6-methyladenosine (m6A) demethylase that participates in tumorigenesis and is associated with the prognosis of patients in some cancers. However, the key roles of FTO in pan-cancer are still largely obscure.

Methods

FTO expression levels in pan-cancer were estimated via the Genotype-Tissue Expression (GTEx), Cancer Cell Line Encyclopedia (CCLE), and The Cancer Genome Atlas (TCGA) databases. Univariate survival analysis was used to estimate the effects of FTO on prognosis. In addition, we used the Tumor Immune Evaluation Resource (TIMER) to assess the immune cell infiltration of FTO gene across cancers. The association of FTO expression with immune checkpoint genes expression, DNA mismatch repair (MMR) gene mutation, DNA methyltransferases, microsatellite instability (MSI), and tumor mutational burden (TMB) was investigated using Spearman’s correlation analysis. Moreover, Gene Set Enrichment Analysis (GSEA) was utilized to identify critical pathways in cancers. The STRING website was used to reveal the protein–protein interaction (PPI) network of FTO.

Results

FTO was aberrantly expressed across cancers and survival analysis demonstrated that its expression was associated with clinical prognosis of many cancer patients. Specifically, FTO expression was significantly associated with immune infiltrating cells in colon adenocarcinoma, kidney renal clear cell carcinoma, and liver hepatocellular carcinoma. In addition, FTO expression was significantly associated with immune checkpoint genes expression, MMR, DNA methyltransferases levels, TMB, and MSI in multiple cancers. Moreover, the GSEA unveiled that FTO was involved in the regulation of tumors and immune-related signaling pathways. In addition, several m6A related genes were implicated in the PPI network of FTO.

Conclusion

FTO was related to patients’ prognosis and tumor immune infiltrates in various cancers, and may serve as a novel and potential prognostic and immune biomarker in human pan-cancer.

miR-17-5p drives G2/M-phase accumulation by directly targeting CCNG2 and is related to recurrence of head and neck squamous cell carcinoma

Background

The human miR-17-92 polycistron is the first reported and most well-studied onco-miRNA with a cluster of seven miRNAs. miR-17-5p, a member of the miR-17-92 family, plays an important role in tumor cell proliferation, apoptosis, migration and invasion. However, few studies have shown the role of miR-17-5p in the cell cycle of head and neck squamous cell carcinoma (HNSCC).

Methods

RT-qPCR was used to detect miR-17-5p expression levels in 64 HNSCC tissues and 5 cell lines. The relationship between the expression of miR-17-5p in the tissues and the clinical characteristics of the patients was analyzed. HNSCC cells were transfected with an miR-17-5p mimic or inhibitor to evaluate cell cycle distribution by flow cytometry. Cell cycle distribution of cells transfected with target gene was evaluated using flow cytometry. Dual-luciferase reporter assay was used to detect the regulatory effect of miR-17-5p on target gene expression.

Results

In the present study, we found that miR-17-5p expression in HNSCC tissues and cell lines was remarkably increased, and miR-17-5p is related to recurrence in HNSCC patients. Silencing miR-17-5p blocked HNSCC cells in G2/M phase, whereas its overexpression propelled cell cycle progression. More importantly, we verified that miR-17-5p negatively regulated CCNG2 mRNA and protein expression by directly targeting its 3’UTR.

Conclusion

These findings suggest that miR-17-5p might act as a tumor promoter and prognostic factor for recurrence in HNSCC patients.