STAT3/HOTAIR Signaling Axis Regulates HNSCC Growth in an EZH2-dependent Manner

Targeting STAT3 potentiates CDK4/6 inhibitors therapy in head and neck squamous cell carcinoma

Anti-CDK4/6 therapy has been employed for the treatment for head and neck squamous cell carcinoma (HNSCC) with CDK4/6 hyperactivation, but the response rate is relatively low. In this study, we first showed that CDK4 and CDK6 was over-expressed and conferred poor prognosis in HNSCC. Moreover, in RB-positive HNSCC, STAT3 signaling was activated induced by CDK4/6 inhibition and STAT3 promotes RB deficiency by upregulation of MYC. Thirdly, the combination of Stattic and CDK4/6 inhibitor results in striking anti-tumor effect in vitro and in Cal27 derived animal models. Additionally, phospho-STAT3 level negatively correlates with RB expression and predicts poor prognosis in patients with HNSCC. Taken together, our findings suggest an unrecognized function of STAT3 confers to CDK4/6 inhibitors resistance and presenting a promising combination strategy for patients with HNSCC.

Polycomb repressive complex 2 and its core component EZH2: potential targeted therapeutic strategies for head and neck squamous cell carcinoma

The polycomb group (PcG) comprises a set of proteins that exert epigenetic regulatory effects and play crucial roles in diverse biological processes, ranging from pluripotency and development to carcinogenesis. Among these proteins, enhancer of zeste homolog 2 (EZH2) stands out as a catalytic component of polycomb repressive complex 2 (PRC2), which plays a role in regulating the expression of homologous (Hox) genes and initial stages of x chromosome inactivation. In numerous human cancers, including head and neck squamous cell carcinoma (HNSCC), EZH2 is frequently overexpressed or activated and has been identified as a negative prognostic factor. Notably, EZH2 emerges as a significant gene involved in regulating the STAT3/HOTAIR axis, influencing HNSCC proliferation, differentiation, and promoting metastasis by modulating related oncogenes in oral cancer. Currently, various small molecule compounds have been developed as inhibitors specifically targeting EZH2 and have gained approval for treating refractory tumors. In this review, we delve into the epigenetic regulation mediated by EZH2/PRC2 in HNSCC, with a specific focus on exploring the potential roles and mechanisms of EZH2, its crucial contribution to targeted drug therapy, and its association with cancer markers and epithelial-mesenchymal transition. Furthermore, we aim to unravel its potential as a therapeutic strategy for oral squamous cell carcinoma.

Targeting IL-6/STAT3 signaling abrogates EGFR-TKI resistance through inhibiting Beclin-1 dependent autophagy in HNSCC

Head and neck squamous cell carcinoma (HNSCC) is featured by notorious EGFR tyrosine kinase inhibitor (TKI) resistance attributable to activation of parallel pathways. The numerous phase I/II trials have rarely shown encouraging clinical outcomes of EGFR-TKIs during treatment in HNSCC patients with advanced tumors. A unique IL-6/STAT3 signaling axis is reported to regulate multiple cancer-related pathways, but whether this signaling is correlated with reduced EGFR-TKI responsiveness is unclear. Here, we found that STAT3 signaling is compensatorily upregulated after EGFR-TKI exposure and confers anti-EGFR therapy resistance during HNSCC therapy. Targeting STAT3 using small molecule inhibitors promotes complete recovery or sustained elimination of HNSCC tumors through combination with EGFR-TKIs both in vitro and in diverse animal models. Mechanistically, phosphorylated STAT3 was proven to enhance oncogenic autophagic flux, protecting cancer cells and preventing EGFR-TKI-induced tumor apoptosis. Thus, blockade of STAT3 signaling simultaneously disrupts several key interactions during tumor progression and remodels the autophagic degradation system, thereby rendering advanced HNSCC eradicable through combination with EGFR-TKI therapy. These findings provide a clinically actionable strategy and suggest STAT3 as a predictive biomarker with therapeutic potential for EGFR-TKI resistant HNSCC patients.

Investigating diagnostic potential of long non-coding RNAs in head and neck squamous cell carcinoma using TCGA database and clinical specimens

Head and neck squamous cell carcinoma (HNSCC) is a prevalent and prognostically challenging cancer worldwide. The role of long non-coding RNAs (lncRNAs) in cancer regulation is progressively being understood. This study aims to identify lncRNAs with diagnostic potential as biomarkers for HNSCC. Statistical analysis was performed on expression data from the Cancer Genome Atlas (TCGA) database to identify potential lncRNAs associated with HNSCC. Four selected lncRNAs were validated using real-time quantitative reverse transcription polymerase chain reaction and correlated with clinical factors. Functional roles were further investigated. A total of 488 differentially expressed lncRNAs were identified in TCGA-HNSC. After rigorous evaluation based on p-values, survival analysis, and ROC analysis, 24 lncRNAs were prioritized for additional investigation. LINC00460, LINC00941, CTC-241F20.4, and RP11-357H14.17 were established as candidate diagnostic biomarkers. These lncRNAs exhibited elevated expression in HNSCC tissues and were associated with poor prognosis. Combining them showed high diagnostic accuracy. Notably, LINC00460 and CTC-241F20.4 demonstrated a significant elevation in the advanced stages of HNSCC. We constructed an lncRNA-mRNA regulatory network, and the array of significant regulatory pathways identified included focal adhesion, regulation of epithelial cell migration, and others. Additionally, these lncRNAs were found to influence immune responses by modulating immune cell infiltration in the HNSCC microenvironment. Our research indicates that LINC00460, LINC00941, RP11-357H14.17, and CTC-241F20.4 may have diagnostic and prognostic importance in HNSCC. Furthermore, we have gained insights into their potential functional roles, particularly about immune responses and interactions in the microenvironment.

The role of stromal cells in epithelial-mesenchymal plasticity and its therapeutic potential

The epithelial-mesenchymal transition (EMT) is a critical tumor invasion and metastasis process. EMT enables tumor cells to migrate, detach from their original location, enter the circulation, circulate within it, and eventually exit from blood arteries to colonize in foreign sites, leading to the development of overt metastases, ultimately resulting in death. EMT is intimately tied to stromal cells around the tumor and is controlled by a range of cytokines secreted by stromal cells. This review summarizes recent research on stromal cell-mediated EMT in tumor invasion and metastasis. We also discuss the effects of various stromal cells on EMT induction and focus on the molecular mechanisms by which several significant stromal cells convert from foes to friends of cancer cells to fuel EMT processes via their secretions in the tumor microenvironment (TME). As a result, a better knowledge of the role of stromal cells in cancer cells' EMT may pave the path to cancer eradication.

EZH2 as a potential therapeutic target for gastrointestinal cancers

Gastrointestinal (GI) cancers continue to be a major cause of mortality and morbidity globally. Understanding the molecular pathways associated with cancer progression and severity is essential for creating effective cancer treatments. In cancer research, there is a notable emphasis on Enhancer of zeste homolog 2 (EZH2), a key player in gene expression influenced by its irregular expression and capacity to attach to promoters and alter methylation status. This review explores the impact of EZH2 signaling on various GI cancers, such as colorectal, gastric, pancreatic, hepatocellular, esophageal, and cholangiocarcinoma. The primary function of EZH2 signaling is to facilitate the accelerated progression of cancer cells. Additionally, EZH2 has the capacity to modulate the reaction of GI cancers to chemotherapy and radiotherapy. Numerous pathways, including long non-coding RNAs and microRNAs, serve as upstream regulators of EZH2 in these types of cancer. EZH2's enzymatic activity enables it to attach to target gene promoters, resulting in methylation that modifies their expression. EZH2 could be considered as an independent prognostic factor, with increased expression correlating with a worse disease prognosis. Additionally, a range of gene therapies including small interfering RNA, and anti-tumor agents are being explored to target EZH2 for cancer treatment. This comprehensive review underscores the current insights into EZH2 signaling in gastrointestinal cancers and examines the prospect of therapies targeting EZH2 to enhance patient outcomes.

A Novel LncRNA MASCC1 Regulates the Progression and Metastasis of Head and Neck Squamous Cell Carcinoma by Sponging miR-195

The altered expression of long noncoding RNAs (lncRNAs) is associated with human carcinogenesis. We performed a high-throughput analysis of lncRNA expression in strictly selected pairs of metastatic head and neck squamous cell carcinoma (HNSCC) and non-metastatic HNSCC samples. We identified a novel lncRNA, which was highly expressed in metastatic HNSCC, named Metastasis Associated Squamous Cell Carcinoma 1 (MASCC1), for further study. Using qRT-PCR, we further compared MASCC1 expression in 60 HNSCC samples. The results show that high expression of MASCC1 in patients with HNSCC was related to poor prognosis. In vitro, MASCC1 knockdown (KD) inhibited HNSCC proliferation, migration, invasion, and tumor sphere formation, while promoting apoptosis. In vivo, MASCC1 KD inhibited HNSCC growth and lymph node metastasis. Mechanistically, MASCC1 acted as a competing endogenous RNA (ceRNA) by binding to miR-195, subsequently regulating the expression of Cyclin D1, BCL-2, and YAP1. Moreover, miR-195 overexpression rescued the effects of MASCC1 on the biological behaviors of HNSCC. Taken together, our results suggest that MASCC1 is a novel oncogene that can predict the prognosis of patients with HNSCC and is a potential therapeutic target for HNSCC intervention.

Apoptotic activity of genipin in human oral squamous cell carcinoma in vitro by regulating STAT3 signaling

Genipin, a natural compound derived from the fruit of Gardenia jasminoides Ellis, was reported to have activity against various cancer types. In this study, we determined the underlying mechanism for genipin-induced cell death in human oral squamous cell carcinoma (OSCC). The growth-inhibitory effects of genipin in human OSCC cells was examined by the Cell Counting Kit-8 and soft agar assays. The effects of genipin on apoptosis were assessed by nuclear morphological changes by 4',6-diamidino-2-phenylindole staining, measurement of the sub-G1 population, and Annexin V-fluorescein isothiocyanate/propidium iodide double staining. The underlying mechanism of genipin activity was analyzed by western blot analysis, subcellular fractionation of the nucleus and cytoplasm, immunocytochemistry, and quantitative real-time polymerase chain reaction. Genipin inhibited the growth of OSCC cells and induced apoptosis, which was mediated by a caspase-dependent pathway. Genipin reduced the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at Tyr705 and its nuclear localization. Furthermore, inhibition of p-STAT3Tyr705 levels following genipin treatment was required for the reduction of survivin and myeloid cell leukemia-1 (Mcl-1) expression, leading to apoptotic cell death. The genipin-mediated reduction in survivin and Mcl-1 expression was caused by transcriptional and/or posttranslational regulatory mechanisms. The results provide insight into the regulatory mechanism by which genipin induces apoptotic cell death through the abrogation of nuclear STAT3 phosphorylation and suggest that genipin may represent a potential therapeutic option for the treatment of human OSCC.

Phosphorylation of EZH2 differs HER2-positive breast cancer invasiveness in a site-specific manner

HER2-positive breast cancer (BC) invasiveness and drug-resistance issue is the critical treatment obstacle recently. We investigated the total and phosphorylated status EZH2 expression in database and BC tissue microarray. We demonstrated for the first time that EZH2 is distributed both in cytoplasm and nucleus of breast cancer cells in a phosphorylation site-specific manner. High expressed-EZH2 cases more frequently had an advanced clinical stage (lymph node metastasis) and aggressive features than EZH2-low cases, potentially indicating the high risk of HER2-positive BC (p < 0.05). Notably, highly expressed phosphorylated EZH2 is differently located in cytoplasm or nucleus in a site-specific manner in breast cancer cells. Nucleus-located pEZH2-S21 is expressed in invasive and lymph node metastatic HER2-positive BC cases (p = 0.144, p = 0.001). Cytoplasmic pEZH2-T487 is correlated with HER2 positive status (p = 0.014).In conclusion, high expression of nucleus-located EZH2 might be a predictor of invasive BC. Activation of phosphorylated EZH2-S21 site in nucleus would be a potential predictor of HER2-positve BC and poor efficacy of HER2-target therapy. These results point to a PRC2-independent non-epigenetic mechanism and therapeutic strategy of EZH2 in HER2-positive BC.

RNA-Based Liquid Biopsy in Head and Neck Cancer

Head and neck cancer (HNC) is a prevalent and diverse group of malignancies with substantial morbidity and mortality rates. Early detection and monitoring of HNC are crucial for improving patient outcomes. Liquid biopsy, a non-invasive diagnostic approach, has emerged as a promising tool for cancer detection and monitoring. In this article, we review the application of RNA-based liquid biopsy in HNC. Various types of RNA, including messenger RNA (mRNA), microRNA (miRNA), long non-coding RNA (lncRNA), small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), circular RNA (circRNA) and PIWI-interacting RNA (piRNA), are explored as potential biomarkers in HNC liquid-based diagnostics. The roles of RNAs in HNC diagnosis, metastasis, tumor resistance to radio and chemotherapy, and overall prognosis are discussed. RNA-based liquid biopsy holds great promise for the early detection, prognosis, and personalized treatment of HNC. Further research and validation are necessary to translate these findings into clinical practice and improve patient outcomes.

HOTAIR: a potential metastatic, drug-resistant and prognostic regulator of breast cancer

HOX transcript antisense intergenic RNA (HOTAIR) is an oncogenic non-coding RNA whose expression is strongly correlated with the tumor grade and prognosis of a variety of carcinomas including breast cancer (BC). HOTAIR regulates various target genes via sponging and epigenetic mechanisms and controls various oncogenic cellular and signaling mechanisms including metastasis and drug resistance. In BC cells, HOTAIR expression is regulated by a variety of transcriptional and epigenetic mechanisms. In this review, we describe the regulatory mechanisms that govern HOTAIR expression during cancer development and explore how HOTAIR drives BC development, metastasis, and drug resistance. In the final section of this review, we focus on the role of HOTAIR in BC management, therapeutic treatment, and prognosis, highlighting its potential therapeutic applications.

The role of LncRNAs in tumor immunotherapy

Cancer immunotherapy is a major breakthrough in the history of tumor therapy in the last decade. Immune checkpoint inhibitors blocking CTLA-4/B7 or PD-1/PD-L1 pathways have greatly prolonged the survival of patients with different cancers. Long non-coding RNAs (lncRNAs) are abnormally expressed in tumors and play an important role in tumor immunotherapy through immune regulation and immunotherapy resistance. In this review, we summarized the mechanisms of lncRNAs in regulating gene expression and well-studied immune checkpoint pathways. The crucial regulatory function of immune-related lncRNAs in cancer immunotherapy was also described. Further understanding of the underlying mechanisms of these lncRNAs is of great importance to the development of taking lncRNAs as novel biomarkers and therapeutic targets for immunotherapy.

EZH2: An Accomplice of Gastric Cancer

Gastric cancer is the fifth most common cancer and the third leading cause of cancer deaths worldwide. Understanding the factors influencing the therapeutic effects in gastric cancer patients and the molecular mechanism behind gastric cancer is still facing challenges. In addition to genetic alterations and environmental factors, it has been demonstrated that epigenetic mechanisms can also induce the occurrence and progression of gastric cancer. Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of the polycomb repressor complex 2 (PRC2), which trimethylates histone 3 at Lys-27 and regulates the expression of downstream target genes through epigenetic mechanisms. It has been found that EZH2 is overexpressed in the stomach, which promotes the progression of gastric cancer through multiple pathways. In addition, targeted inhibition of EZH2 expression can effectively delay the progression of gastric cancer and improve its resistance to chemotherapeutic agents. Given the many effects of EZH2 in gastric cancer, there are no studies to comprehensively describe this mechanism. Therefore, in this review, we first introduce EZH2 and clarify the mechanisms of abnormal expression of EZH2 in cancer. Secondly, we summarize the role of EZH2 in gastric cancer, which includes the association of the EZH2 gene with genetic susceptibility to GC, the correlation of the EZH2 gene with gastric carcinogenesis and invasive metastasis, the resistance to chemotherapeutic drugs of gastric cancer mediated by EZH2 and the high expression of EZH2 leading to poor prognosis of gastric cancer patients. Finally, we also clarify some of the current statuses of drug development regarding targeted inhibition of EZH2/PRC2 activity.

The Role and Mechanism of Long Non-Coding RNA HOTAIR in the Oncogenesis, Diagnosis, and Treatment of Head and Neck Squamous Cell Carcinoma

The most frequent malignant tumor of the head and neck is head and neck squamous cell carcinoma (HNSCC), which has a high frequency, a poor prognosis in the late stages, and subpar therapeutic results. As a result, early HNSCC diagnosis and treatment are urgently needed; however, there are no good diagnostic biomarkers or efficient therapeutic targets at this time. The long-stranded non-coding RNA HOTAIR may be important in the pathogenesis of cancer, according to recent research. By interactions with DNA, RNA, and proteins, it has been demonstrated that HOTAIR, a >200 nucleotide RNA transcript, plays a role in the biological processes of many types of tumor cells, including proliferation, metastasis, and prognosis of HNSCC. Hence, this review discusses HOTAIR's function and molecular mechanisms in HNSCC.

HOTAIR modulates hepatocellular carcinoma progression by activating FUT8/core-fucosylated Hsp90/MUC1/STAT3 feedback loop via JAK1/STAT3 cascade

BACKGROUND

Glycosylation exhibits crucial effect on hepatocellular carcinoma (HCC) progression. Long non-coding RNAs (lncRNAs) are involved in multilevel regulation of gene transcription during tumor development. The purpose of this study is to clarify the potential mechanism that HOTAIR modulates hepatocellular carcinoma progression by activating FUT8/core-fucosylated Hsp90/MUC1/STAT3 feedback loop via JAK1/STAT3 cascade.

METHODS

qRT-PCR was used to show the differential expression of genes. Functional experiments were used to measure the malignancy of HCC cells. ChIP and co-IP assays showed the directly interaction of the key molecules. Xenografts was conducted to show the in vivo effects.

RESULTS

Upregulation of FUT8 showed closely correlation with HCC progression. Core-fucosylation of Hsp90 stabilized MUC1 binding to the downstream p-STAT3, which involved in the activation of JAK1/STAT3 cascade. STAT3 was identified as the regulator of FUT8 and MUC1 transcription, while FUT8 and MUC1 impacted STAT3 level both in nuclear and cytoplasm. HOTAIR recruited P300 to efficiently bind with STAT3. The transcript complex co-modulated the transcrption of FUT8 and MUC1. Moreover, highly HOTAIR expression also exhibited closely correlation with HCC progression.

CONCLUSIONS

FUT8 triggered core-fucosylated-Hsp90/MUC1/P300-HOTAIR-STAT3 cascade via JAK1/STAT3 pathway, which exhibited as positive feedback loop during HCC progression.

Small-molecule PROTAC mediates targeted protein degradation to treat STAT3-dependent epithelial cancer

The aberrant activation of STAT3 is associated with the etiology and progression in a variety of malignant epithelial-derived tumors, including head and neck squamous cell carcinoma (HNSCC) and colorectal cancer (CRC). Due to the lack of an enzymatic catalytic site or a ligand-binding pocket, there are no small-molecule inhibitors directly targeting STAT3 that have been approved for clinical translation. Emerging proteolysis targeting chimeric (PROTAC) technology-based approach represents a potential strategy to overcome the limitations of conventional inhibitors and inhibit activation of STAT3 and downstream genes. In this study, the heterobifunctional small-molecule-based PROTACs are successfully prepared from toosendanin (TSN), with 1 portion binding to STAT3 and the other portion binding to an E3 ubiquitin ligase. The optimized lead PROTAC (TSM-1) exhibits superior selectivity, potency, and robust antitumor effects in STAT3-dependent HNSCC and CRC - especially in clinically relevant patient-derived xenografts (PDX) and patient-derived organoids (PDO). The following mechanistic investigation identifies the reduced expression of critical downstream STAT3 effectors, through which TSM-1 promotes cell cycle arrest and apoptosis in tumor cells. These findings provide the first demonstration to our knowledge of a successful PROTAC-targeting strategy in STAT3-dependent epithelial cancer.

Effect of Diacerein on HOTAIR/IL-6/STAT3, Wnt/β-Catenin and TLR-4/NF-κB/TNF-α axes in colon carcinogenesis

Colorectal cancer (CRC) is a common malignancy with high mortality and poor prognosis. Diacerein (DIA) is an anti-inflammatory used for treatment of osteoarthritis. We delineated some underlying molecular mechanisms of DIA's anti-carcinogenic effect in CRC using in vivo and in vitro models. Human Caco-2 cells were treated with DIA followed by MTT and Annexin V assays and CRC was experimentally induced using 1,2-dimethylhydrazine. DIA (50 mg/kg/day, orally) was administrated for 8 weeks. The MTT assay confirmed cytotoxic effect of DIA in vitro and Annexin V confirmed its apoptotic effect. DIA resulted in regression of tumour lesions with reduced colonic TLR4, NF-κB and TNF-α protein levels and down-regulated VEGF expression, confirming anti-angiogenic impact. DIA triggered caspase-3 expression and regulated Wnt/β-Catenin pathway, by apparently interrupting the IL-6/STAT3/ lncRNA HOTAIR axis. In conclusion, DIA disrupted IL-6/STAT3/ lncRNA HOTAIR axis which could offer an effective therapeutic strategy for the management of CRC.

Promotion or remission: a role of noncoding RNAs in colorectal cancer resistance to anti-EGFR therapy

Anti-epidermal-growth-factor-receptor (EGFR) monoclonal antibodies (mAbs) are of great significance for RAS and BRAF wild-type metastatic colorectal cancer (mCRC) patients. However, the generation of primary and secondary resistance to anti-EGFR mAbs has become an important factor restricting its efficacy. Recent studies have revealed that non-coding RNAs (ncRNAs), especially long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are implicated in anti-EGFR antibodies resistance, affecting the sensitivity of CRC cells to Cetuximab and Panitumumab. This paper briefly reviewed the research advance of the expression, signaling network and functional mechanism of ncRNAs related to anti-EGFR mAbs resistance in CRC, as well as their relationship with clinical prognosis and the possibility of therapeutic targets. In addition, some ncRNAs that are involved in the regulation of signaling pathways or genes related to anti-EGFR resistance, but need to be further verified by resistance experiments were also included in this review, thereby providing more ideas and basis for ncRNAs as CRC prognostic markers and anti-EGFR therapy sensitizers. Video Abstract.

The role of tumor-associated macrophages in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common head and neck cancer with a high recurrence rate and a low 5-year survival rate. Tumor-associated macrophages (TAMs) are important immune cells in the tumor microenvironment, which play an important role in the progression of many tumors. This article reviews the origin, and the role of TAMs in the invasion, metastasis, angiogenesis and immunosuppression of OSCC. Therapeutic strategies targeting TAMs are also discussed in hopes of providing new ideas for the treatment of OSCC.

The role of long non-coding RNAs in the pathogenesis of head and neck squamous cell carcinoma

Head and neck cancers are a heterogeneous collection of malignancies of the upper aerodigestive tract, salivary glands, and thyroid. However, the molecular mechanisms underlying the carcinogenesis of head and neck squamous cell carcinomas (HNSCCs) remain poorly understood. Over the past decades, overwhelming evidence has demonstrated the regulatory roles of long non-coding RNAs (lncRNAs) in tumorigenesis, including HNSCC. Notably, these lncRNAs have vital roles in gene regulation and affect various aspects of cellular homeostasis, including proliferation, survival, and metastasis. They exert regulating functions by interacting with nucleic acids or proteins and affecting cancer cell signaling. LncRNAs represent a burgeoning field of cancer research, and we are only beginning to understand the importance and complicity of lncRNAs in HNSCC. In this review, we summarize the deregulation and function of lncRNAs in human HNSCC. We also review the working mechanism of lncRNAs in HNSCC pathogenesis and discuss the potential application of lncRNAs as diagnostic/prognostic tools and therapeutic targets in human HNSCC.

Glycoprotein PTGDS promotes tumorigenesis of diffuse large B-cell lymphoma by MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling

Glycoprotein prostaglandin D2 synthase (PTGDS) is a member of the lipocalin superfamily and plays dual roles in prostaglandins metabolism and lipid transport. PTGDS has been involved in various cellular processes including the tumorigenesis of solid tumors, yet its role in carcinogenesis is contradictory and the significance of PTGDS in hematological malignancies is ill-defined. Here, we aimed to explore the expression and function of PTGDS in diffuse large B-cell lymphoma (DLBCL), especially the potential role of PTGDS inhibitor, AT56, in lymphoma therapy. Remarkable high expression of PTGDS was found in DLBCL, which was significantly correlated with poor prognosis. PTGDS overexpression and rhPTGDS were found to promote cell proliferation. Besides, in vitro and in vivo studies indicated that PTGDS knockdown and AT56 treatment exerted an anti-tumor effect by regulating cell viability, proliferation, apoptosis, cell cycle, and invasion, and enhanced the drug sensitivity to adriamycin and bendamustine through promoting DNA damage. Moreover, the co-immunoprecipitation-based mass spectrum identified the interaction between PTGDS and MYH9, which was found to promote DLBCL progression. PTGDS inhibition led to reduced expression of MYH9, and then declined activation of the Wnt-β-catenin-STAT3 pathway through influencing the ubiquitination and degradation of GSK3-β in DLBCL. The rescue experiment demonstrated that PTGDS exerted an oncogenic role through regulating MYH9 and then the Wnt-β-catenin-STAT3 pathway. Based on point mutation of glycosylation sites, we confirmed the N-glycosylation of PTGDS in Asn51 and Asn78 and found that abnormal glycosylation of PTGDS resulted in its nuclear translocation, prolonged half-life, and enhanced cell proliferation. Collectively, our findings identified for the first time that glycoprotein PTGDS promoted tumorigenesis of DLBCL through MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling, and highlighted the potential role of AT56 as a novel therapeutic strategy for DLBCL treatment.

EZH2, a prominent orchestrator of genetic and epigenetic regulation of solid tumor microenvironment and immunotherapy

Immune checkpoint blockade (ICB) is regarded as a promising strategy for cancer therapy. The histone methyltransferase, Enhancer of Zeste Homolog 2 (EZH2), has been implicated in the carcinogenesis of numerous solid tumors. However, the underlying mechanism of EZH2 in cancer immunotherapeutic resistance remains unknown. EZH2 orchestrates the regulation of the innate and adaptive immune systems of the tumor microenvironment (TME). Profound epigenetic and transcriptomic changes induced by EZH2 in tumor cells and immune cells mobilize the elements of the TME, leading to immune-suppressive activity of solid tumors. In this review, we summarized the dynamic functions of EZH2 on the different components of the TME, including tumor cells, T cells, macrophages, natural killer cells, myeloid-derived suppressor cells, dendritic cells, fibroblasts, and mesenchymal stem cells. Several ongoing anti-tumor clinical trials using EZH2 inhibitors have also been included as translational perspectives. In conclusion, based combinational therapy to enable ICB could offer a survival benefit in patients with cancer.

Homeobox Genes in Cancers: From Carcinogenesis to Recent Therapeutic Intervention

The homeobox (HOX) genes encoding an evolutionarily highly conserved family of homeodomain-containing transcriptional factors are essential for embryogenesis and tumorigenesis. HOX genes are involved in cell identity determination during early embryonic development and postnatal processes. The deregulation of HOX genes is closely associated with numerous human malignancies, highlighting the indispensable involvement in mortal cancer development. Since most HOX genes behave as oncogenes or tumor suppressors in human cancer, a better comprehension of their upstream regulators and downstream targets contributes to elucidating the function of HOX genes in cancer development. In addition, targeting HOX genes may imply therapeutic potential. Recently, novel therapies such as monoclonal antibodies targeting tyrosine receptor kinases, small molecular chemical inhibitors, and small interfering RNA strategies, are difficult to implement for targeting transcriptional factors on account of the dual function and pleiotropic nature of HOX genes-related molecular networks. This paper summarizes the current state of knowledge on the roles of HOX genes in human cancer and emphasizes the emerging importance of HOX genes as potential therapeutic targets to overcome the limitations of present cancer therapy.

PD-L2 glycosylation promotes immune evasion and predicts anti-EGFR efficacy

Background

Combination therapy has been explored for advanced head and neck squamous cell carcinoma (HNSCC) owing to the limited efficacy of anti-epidermal growth factor receptor (EGFR) therapy. Increased expression and glycosylation of immune checkpoint molecules in tumors are responsible for cetuximab therapy refractoriness. The role of programmed death ligand 2 (PD-L2), a ligand of PD-1, in the immune function is unclear. Here, we examined the regulatory mechanism of PD-L2 glycosylation and its role in antitumor immunity and cetuximab therapy.

Methods

Single-cell RNA sequencing and immunohistochemical staining were used to investigate PD-L2 expression in cetuximab-resistant/sensitive HNSCC tissues. The mechanism of PD-L2 glycosylation regulation was explored in vitro. The effects of PD-L2 glycosylation on immune evasion and cetuximab efficacy were verified in vitro and using mice bearing orthotopic SCC7 tumors.

Results

The PD-L2 levels were elevated and N-glycosylated in patients with cetuximab-resistant HNSCC. Glycosylated PD-L2 formed a complex with EGFR, which resulted in the activation of EGFR/signal transducer and activator of transcription 3 (STAT3) signaling and decreased the cetuximab binding affinity to EGFR. The N-glycosyltransferase fucosyltransferase (FUT8), a transcriptional target of STAT3, was required for PD-L2 glycosylation. Moreover, glycosylation modification stabilized PD-L2 by blocking ubiquitin-dependent lysosomal degradation, which consequently promoted its binding to PD-1 and immune evasion. Inhibition of PD-L2 glycosylation using Stattic, a specific STAT3 inhibitor, or PD-L2 mutation blocking its binding to FUT8, increased cytotoxic T lymphocyte activity and augmented response to cetuximab.

Conclusions

Increased expression and glycosylation of PD-L2 in tumors are an important mechanism for cetuximab therapy refractoriness. Thus, the combination of PD-L2 glycosylation inhibition and cetuximab is a potential therapeutic strategy for cancer.

Mechanistic study of lncRNA UCA1 promoting growth and cisplatin resistance in lung adenocarcinoma

Aim

This study aimed to explore the mechanism of LncRNA urothelial carcinoma-associated 1 (UCA1) promoting cisplatin resistance in lung adenocarcinoma (LUAD).

Method

The UCA1 expression level in LUAD cell lines was detected by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). We overexpressed UCA1 in A549 cells and downregulated UCA1 in A549/DDP cells by the lentivirus‑mediated technique. Subsequently, in vitro, and in vivo functional experiments were performed to investigate the functional roles of UCA1 in the growth and metastasis of LUAD cell lines. Furthermore, RNA pulldown, mass spectrometry, and RNA immunoprecipitation technique were performed to analyze various downstream target factors regulated by UCA1.

Results

The results revealed a higher UCA1 expression level in A549/DDP cells and LUAD tissues than in A549 cells and adjacent cancer tissues. UCA1 expression was significantly associated with distant metastasis, clinical stage, and survival time of patients with LUAD. UCA1 overexpression significantly increased the proliferation, invasion, clone formation, and cisplatin resistance ability and enhanced the expression levels of proliferating cell nuclear antigen and excision repair cross-complementing gene 1 in A549 cells. However, these trends were mostly reversed after the knockdown of UCA1 in A549/DDP cells. Tumorigenic assays in nude mice showed that UCA1 knockdown significantly inhibited tumor growth and reduced cisplatin resistance. Enolase 1 was the RNA-binding protein (RBP) of UCA1.

Conclusion

Based on the results, we concluded that UCA1 promoted LUAD progression and cisplatin resistance and hence could be a potential diagnostic marker and therapeutic target in patients with LUAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02207-0.

A novel intronic circular RNA, circGNG7, inhibits head and neck squamous cell carcinoma progression by blocking the phosphorylation of heat shock protein 27 at Ser78 and Ser82

Background

There is increasing evidence that circular RNAs (circRNAs) play a significant role in pathological processes including tumorigenesis. In contrast to exonic circRNAs, which are the most frequently reported circRNAs in cancer so far, the studies of intronic circRNAs have been greatly lagged behind. Here, we aimed to investigate the regulatory role of intronic circRNAs in head and neck squamous cell carcinoma (HNSCC).

Methods

We conducted whole‐transcriptome sequencing with four pairs of primary tumor tissues and adjacent normal tissues from HNSCC patients. Then, we characterized circGNG7 expression in HNSCC tissues and cell lines and explored its association with the prognosis of HNSCC patients. We also identified interactions between circGNG7 and functional proteins, which alter downstream signaling that regulate HNSCC progression.

Results

In this study, we identified a new intronic circRNA, circGNG7, and validated its functional roles in HNSCC progression. CircGNG7 was predominately localized to the cytoplasm, and its expression was downregulated in both HNSCC tissues andCAL27, CAL33, SCC4, SCC9, HN6, and HN30 cells. Low expression of circGNG7 was significantly correlated with poor prognosis in HNSCC patients. Consistent with this finding, overexpression of circGNG7 strongly inhibited tumor cell proliferation, colony formation, in vitro migration, and in vivo tumor growth. Mechanistically, the expression of circGNG7 in HNSCC cells was regulated by the transcription factor SMAD family member 4 (SMAD4). Importantly, we discovered that circGNG7 could bind to serine residues 78 and 82 of the functional heat shock protein 27 (HSP27), occupying its phosphorylation sites and hindering its phosphorylation, which reduced HSP27‐JNK/P38 mitogen‐activated protein kinase (MAPK) oncogenic signaling. Downregulation of circGNG7 expression in HNSCC increased HSP27‐JNK/P38 MAPK signaling and promoted tumor progression.

Conclusions

Our results revealed that a new intronic circRNA, circGNG7, functions as a strong tumor suppressor and that circGNG7/HSP27‐JNK/P38 MAPK signaling is a novel mechanism by which HNSCC progression can be controlled.

Genome-Wide Enhancer Analysis Reveals the Role of AP-1 Transcription Factor in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world, but its epigenomic features have not been determined. Here, we studied the chromatin landscape of active enhancers of HNSCC head tumor tissues by performing H3K27ac and H3K4me1 ChIP-Seq with a Tgfbr1/Pten double conditional knockout HNSCC mouse model. We identified 1,248 gain variant enhancer loci (VELs) and 2,188 lost VELs, as well as 153 gain variant super enhancer loci (VSELs) and 234 lost VSELs. Potentially involved transcription factors were predicted with motif analysis, and we identified AP-1 as one of the critical oncogenic transcription factors in HNSCC and many other types of cancer. Combining transcriptomic and epigenomic data, our analysis also showed that AP-1 and histone modifications coordinately regulate target gene expression in HNSCC. In conclusion, our study provides important epigenomic information for enhancer studies in HNSCC and reveals new mechanism for AP-1 regulating HNSCC.

Systematic analysis of Long non-coding RNAs reveals diagnostic biomarkers and potential therapeutic drugs for intervertebral disc degeneration

Long non-coding RNAs (lncRNAs) are related to a variety of human diseases. However, little is known about the role of lncRNA in intervertebral disc degeneration (IDD). LncRNA expression profile of human IDD were downloaded from Gene Expression Omnibus (GEO) database. Potential biomarkers and therapeutic drugs for IDD were analyzed by weighted gene co-expression network analysis (WGCNA), R software package Limma, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). We identified 1455 differentially expressed genes and 423 differentially expressed lncRNAs. Twenty-six co-expression modules were obtained, among them, the tan, brown, and turquoise modules were most closely related to IDD. The turquoise module contained a large number of differential expressed lncRNAs and genes, these genes were mainly enriched in the MAPK signaling pathway, TGF-beta signaling pathway. Furthermore, we obtained 11,857 LmiRM-Degenerated, these lncRNAs and genes showed higher differential expression multiples and higher expression correlation. After constructing a disease-gene interaction network, 25 disease-specific genes and 9 disease-specific lncRNAs were identified. Combined with the drug-target gene interaction network, three drugs, namely, Calcium citrate, Calcium Phosphate, and Calcium phosphate dihydrate, which may have curative effects on IDD, were determined. Finally, a genetic diagnosis model and lncRNA diagnosis model with 100% diagnostic performance in both the training data set and the validation data set were established based on these genes and lncRNA. This study provided new diagnostic features for IDD and could help design personalized treatment of IDD.

Cav1/EREG/YAP Axis in the Treatment Resistance of Cav1-Expressing Head and Neck Squamous Cell Carcinoma

Simple Summary

The EGFR-targeting antibody cetuximab (CTX) combined with radiotherapy has been proven effective for the treatment of locally advanced head and neck squamous cell carcinoma (LA-HNSCC). Due to resistance to CTX, some patients do not benefit from the treatment and recurrence is observed. As caveolin-1 (Cav1) has been reported to affect the EGFR pathway, we aimed to elucidate how it might affect the response to CTX-radiotherapy. We showed that Cav1 expression conferred surviving, growing and motile capacities that protect cells against the combination of CTX-radiotherapy. The protecting effects of Cav1 are mediated by the Cav1/EREG/YAP axis. We also showed in a retrospective study that a high expression of Cav1 was predictive of locoregional relapse of LA-HNSCC. Cav1 should be taken into consideration in the future as a prognosis marker to identify the subgroup of advanced HNSCC at higher risk of recurrence, but also to help clinicians to choose the more appropriate therapeutic strategies.

Abstract

The EGFR-targeting antibody cetuximab (CTX) combined with radiotherapy is the only targeted therapy that has been proven effective for the treatment of locally advanced head and neck squamous cell carcinoma (LA-HNSCC). Recurrence arises in 50% of patients with HNSCC in the years following treatment. In clinicopathological practice, it is difficult to assign patients to classes of risk because no reliable biomarkers are available to predict the outcome of HPV-unrelated HNSCC. In the present study, we investigated the role of Caveolin-1 (Cav1) in the sensitivity of HNSCC cell lines to CTX-radiotherapy that might predict HNSCC relapse. Ctrl- and Cav-1-overexpressing HNSCC cell lines were exposed to solvent, CTX, or irradiation, or exposed to CTX before irradiation. Growth, clonogenicity, cell cycle progression, apoptosis, metabolism and signaling pathways were analyzed. Cav1 expression was analyzed in 173 tumor samples and correlated to locoregional recurrence and overall survival. We showed that Cav1-overexpressing cells demonstrate better survival capacities and remain proliferative and motile when exposed to CTX-radiotherapy. Resistance is mediated by the Cav1/EREG/YAP axis. Patients whose tumors overexpressed Cav1 experienced regional recurrence a few years after adjuvant radiotherapy ± chemotherapy. Together, our observations suggest that a high expression of Cav1 might be predictive of locoregional relapse of LA-HNSCC.

N6-Methyladenosine Modification of LncRNA DUXAP9 Promotes Renal Cancer Cells Proliferation and Motility by Activating the PI3K/AKT Signaling Pathway

Most localized human renal clear cell carcinoma (ccRCC)-related deaths result from cancer recurrence and metastasis. However, the precise molecular mechanisms largely remain unknown. In recent years, an increasing number of long noncoding RNAs (lncRNAs) have been shown to be vital regulators of tumorigenesis. In this study, we characterized a lncRNA DUXAP9 and the upregulation of DUXAP9 was analyzed by quantitative real-time PCR in 112 pairs of localized ccRCC tumor tissues compared with adjacent normal tissues. Kaplan–Meier curves showed that patients of localized ccRCC with high DUXAP9 expression had poorer overall survival (P<0.01) and progression-free survival (P<0.05) than cases with low DUXAP9 expression. Multivariate Cox regression analysis also showed that high DUXAP9 expression was an independent risk factor for poor prognosis in localized ccRCC (p<0.05). DUXAP9 knockdown in renal cancer cells inhibited renal cancer cells proliferation and motility capacities in vitro and reversed epithelial–mesenchymal transition (EMT), whereas overexpression of DUXAP9 promoted renal cancer cells proliferation and motility capacities in vitro and induced EMT. Pull-down, RNA immunoprecipitation and RNA stability assays (involving actinomycin D) showed that DUXAP9 was methylated at N6-adenosine and binds to IGF2BP2, which increases its stability. DUXAP9 activate PI3K/AKT pathway and Snail expression in renal cancer cells. DUXAP9 may be useful as a prognostic marker and/or therapeutic target in localized ccRCC.

Myristoylation-mediated phase separation of EZH2 compartmentalizes STAT3 to promote lung cancer growth

N-myristoylation is a crucial signaling and pathogenic modification process that confers hydrophobicity to cytosolic proteins. Although different large-scale approaches have been applied, a large proportion of myristoylated proteins remain to be identified. EZH2 is overexpressed in lung cancer cells and exerts oncogenic effects via its intrinsic methyltransferase activity. Using a well-established click chemistry approach, we found that EZH2 can be modified by myristoylation at its N-terminal glycine in lung cancer cells. Hydrophobic interaction is one of the main forces driving or stabilizing liquid-liquid phase separation (LLPS), raising the possibility that myristoylation can modulate LLPS by mediating hydrophobic interactions. Indeed, myristoylation facilitates EZH2 to form phase-separated liquid droplets in lung cancer cells and in vitro. Furthermore, we provide evidence that myristoylation-mediated LLPS of EZH2 compartmentalizes its non-canonical substrate, STAT3, and activates STAT3 signaling, ultimately resulting in accelerated lung cancer cell growth. Thus, targeting EZH2 myristoylation may have significant therapeutic efficacy in the treatment of lung cancer. Altogether, these observations not only extend the list of myristoylated proteins, but also indicate that hydrophobic lipidation may serve as a novel incentive to induce or maintain LLPS.

Identification of potential core genes and pathways predicting pathogenesis in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the most common subtype of head and neck cancer; however, its pathogenesis and potential therapeutic targets remain largely unknown. In the present study, we analyzed three gene expression profiles and screened differentially expressed genes (DEGs) between HNSCC and normal tissues. The DEGs were subjected to gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG), protein–protein interaction (PPI), and survival analyses, while the connectivity map (CMap) database was used to predict candidate small molecules that may reverse the biological state of HNSCC. Finally, we measured the expression of the most relevant core gene in vitro and examined the effect of the top predicted potential drug against the proliferation of HNSCC cell lines. Among the 208 DEGs and ten hub genes identified, CDK1 and CDC45 were associated with unfavorable HNSCC prognosis, and three potential small molecule drugs for treating HNSCC were identified. Increased CDK1 expression was confirmed in HNSCC cells, and menadione, the top predicted potential drug, exerted significant inhibitory effects against HNSCC cell proliferation and markedly reversed CDK1 expression. Together, the findings of the present study suggest that the ten hub genes and pathways identified may be closely related to HNSCC pathogenesis. In particular, CDK1 and CDC45 overexpression could be reliable biomarkers for predicting unfavorable prognosis in patients with HNSCC, while the new candidate small molecules identified by CMap analysis provide new avenues for the development of potential drugs to treat HNSCC.

STAT3/miR-135b/NF-κB axis confers aggressiveness and unfavorable prognosis in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is one of the most commonly diagnosed cancers worldwide but has limited effective therapies. Uncovering the underlying pathological and molecular changes, as well as mechanisms, will improve the treatment. Dysregulated microRNAs (miRNAs) have been proven to play important roles in the initiation and progression of various cancers, including NSCLC. In this manuscript, we identified microRNA-135b (miR-135b) as a tumor-promoting miRNA in NSCLC. We found that miR-135b was significantly upregulated and that its upregulation was associated with poor prognosis in NSCLC patients. miR-135b was an independent prognostic factor in NSCLC. Overexpressing miR-135b significantly promoted the aggressiveness of NSCLC, as evidenced by enhanced cell proliferation, migration, invasion, anti-apoptosis, and angiogenesis in vitro and in vivo, and knockdown of miR-135b had the opposite effects. Mechanistically, our results reveal that miR-135b directly targets the 3'-untranslated region (UTR) of the deubiquitinase CYLD, thereby modulating ubiquitination and activation of NF-κB signaling. Moreover, we found that interleukin-6 (IL-6)/STAT3 could elevate miR-135b levels and that STAT3 directly bound the promoter of miR-135b; thus, these findings highlight a new positive feedback loop of the IL-6/STAT3/miR-135b/NF-κB signaling in NSCLC and suggest that miR-135b could be a potential therapeutic target for NSCLC.

Targeting epigenetic modulation of cholesterol synthesis as a therapeutic strategy for head and neck squamous cell carcinoma

The histone methyltransferase EZH2 silences gene expression via H3 lysine 27 trimethylation and has been recognized as an important antitumour therapeutic target. However, the clinical application of existing EZH2 inhibitors is not satisfactory for the treatment of solid tumours. To discover novel strategies against head and neck squamous cell carcinoma (HNSCC), we performed genomics, metabolomics and RNA omics studies in HNSCC cells treated with EZH2 inhibitors. It was found that EZH2 inhibitors strongly induced the expression of genes in cholesterol synthesis. Through extensive drug screening we found that inhibition of squalene epoxidase (a key enzyme of endogenous cholesterol synthesis) synergistically increased the squalene content and enhanced the sensitivity of HNSCC cells to EZH2 inhibitors. Our findings provide an experimental and theoretical basis for the development of new combinations of EZH2 inhibitors to treat HNSCC.

Long non-coding RNAs in head and neck squamous cell carcinoma: Diagnostic biomarkers, targeted therapies, and prognostic roles

At present, emerging evidence shows that non-coding RNAs (ncRNAs) play crucial roles for development of multiple tumors. Amongst these ncRNAs, long non-coding RNAs (lncRNAs) play prominent roles in physiological and pathological processes. LncRNAs are RNA transcripts larger than 200 nucleotides and have been shown to serve important regulatory roles in different types of cancer via interactions with DNA, RNA and proteins. Head and neck squamous cell carcinoma (HNSCC) is one of the most malignant tumors with low survival rates in advanced stages. Recently, lncRNAs have been demonstrated to be involved in a wide range of biological processes, including proliferation, metastasis, and prognosis of HNSCC. Therefore, this review describes molecular mechanisms of up- or down-regulation of lncRNAs and expounds their functions in pathology and clinical practices in HNSCC. It also highlights their potential clinical applications as biomarkers for the diagnosis, prognosis, and treatment of HNSCC. However, studies on lncRNAs are still not comprehensive, and more investigations are needed in the future.

Regulatory role of long non-coding RNA UCA1 in signaling pathways and its clinical applications

Long non-coding RNA metastasis-associated urothelial carcinoma associated 1 (UCA1) plays a pivotal role in various human diseases. Its gene expression is regulated by several factors, including transcription factors, chromatin remodeling and epigenetic modification. UCA1 is involved in the regulation of the PI3K/AKT, Wnt/β-catenin, MAPK, NF-κB and JAK/STAT signaling pathways, affecting a series of cellular biological functions, such as cell proliferation, apoptosis, migration, invasion and tumor drug resistance. Furthermore, UCA1 is used as a novel potential biomarker for disease diagnosis and prognosis, as well as a target for clinical gene therapy. The present review systematically summarizes and elucidates the mechanisms of upstream transcriptional regulation of UCA1, the regulatory role of UCA1 in multiple signaling pathways in the occurrence and development of several diseases, and its potential applications in clinical treatment.

Dual relationship between long non-coding RNAs and STAT3 signaling in different cancers: New insight to proliferation and metastasis

Uncontrolled growth and metastasis of cancer cells is an increasing challenge for overcoming cancer, and improving survival of patients. Complicated signaling networks account for proliferation and invasion of cancer cells that need to be elucidated for providing effective cancer therapy, and minimizing their malignancy. Long non-coding RNAs (lncRNAs) are RNA molecules with a length of more than 200 nucleotides. They participate in cellular events, and their dysregulation in a common phenomenon in different cancers. Noteworthy, lncRNAs can regulate different molecular pathways, and signal transducer and activator of transcription 3 (STAT3) is one of them. STAT3 is a tumor-promoting factors in cancers due to its role in cancer proliferation (cell cycle progression and apoptosis inhibition) and metastasis (EMT induction). LncRNAs can function as upstream mediators of STAT3 pathway, reducing/enhancing its expression. This dual relationship is of importance in affecting proliferation and metastasis of cancer cells. The response of cancer cells to therapy such as chemotherapy and radiotherapy is regulated by lncRNA/STAT3 axis. Tumor-promoting lncRNAs including NEAT1, SNHG3 and H19 induces STAT3 expression, while tumor-suppressing lncRNAs such as MEG3, PTCSC3 and NKILA down-regulate STAT3 expression. Noteworthy, upstream mediators of STAT3 such as microRNAs can be regulated by lncRNAs. These complicated signaling networks are mechanistically described in the current review.

Blockade of deubiquitinating enzyme PSMD14 overcomes chemoresistance in head and neck squamous cell carcinoma by antagonizing E2F1/Akt/SOX2-mediated stemness

Increasing evidence reveals a close relationship between deubiquitinating enzymes (DUBs) and cancer progression. In this study, we attempted to identify the roles and mechanisms of critical DUBs in head and neck squamous cell carcinoma (HNSCC).

Methods: Bioinformatics analysis was performed to screen differentially expressed novel DUBs in HNSCC. Immunohistochemistry assay was used to measure the expression of DUB PSMD14 in HNSCC specimens and adjacent normal tissues. The level of PSMD14 in HNSCC tumorigenesis was investigated using a 4-NQO-induced murine HNSCC model. The function of PSMD14 was determined through loss-of-function assays. Chromatin immunoprecipitation, immunoprecipitation and in vivo ubiquitination assay were conducted to explore the potential mechanism of PSMD14. The anti-tumor activity of PSMD14 inhibitor Thiolutin was assessed by in vitro and in vivo experiments.

Results: We identified PSMD14 as one of significantly upregulated DUBs in HNSCC tissues. Aberrant expression of PSMD14 was associated with tumorigenesis and malignant progression of HNSCC and further indicated poor prognosis. The results of in vitro and in vivo experiments demonstrated PSMD14 depletion significantly undermined HNSCC growth, chemoresistance and stemness. Mechanically, PSMD14 inhibited the ubiquitination and degradation of E2F1 to improve the activation of Akt pathway and the transcription of SOX2. Furthermore, PSMD14 inhibitor Thiolutin exhibited a potent anti-tumor effect on HNSCC in vivo and in vitro by impairing DUB activity of PSMD14.

Conclusion: Our findings demonstrate the role and mechanism of PSMD14 in HNSCC, and provide a novel and promising target for diagnosis and clinical therapy of HNSCC.

Inhibition of EZH2 via the STAT3/HOTAIR signalling axis contributes to cell cycle arrest and apoptosis induced by polyphyllin I in human non-small cell lung cancer cells

OBJECTIVE

To explore the potential mechanism of polyphyllin I (PPI)-induced apoptosis in lung cancer cells.

METHODS AND MATERIALS

The pathological changes in lung cancer tissues and paracancerous tissues were first analysed by H&E staining and IHC staining. After PPI treatment, cell viability and apoptosis were detected by MTT assays, cell cycle analyses and flow cytometry. The expression levels of EZH2 and apoptosis-related molecules were evaluated by qRT-PCR and Western blotting.

RESULTS

EZH2 overexpression decreased proapoptotic proteins, and this effect was reversed by PPI. Knockdown of HOTAIR downregulated EZH2 expression, upregulated proapoptotic proteins, and enhanced the effect of PPI treatment. Moreover, knockdown of STAT3 could counteract the effect of HOTAIR overexpression, which significantly increased the expression of EZH2, thus facilitating cell apoptosis in lung cancer.

CONCLUSIONS

PPI induced cell cycle arrest and apoptosis in lung cancer by inhibiting EZH2 through the STAT3/HOTAIR signalling pathway.

The Role of lncRNA Crosstalk in Leading Cancer Metastasis of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of human malignancy. For decades, research into HNSCC invasion and metastasis has been dedicated to the study of protein-coding genes. Along with whole-genome and transcriptome sequencing development, long non-coding RNA (lncRNA) has attracted greater attention. Compelling evidence has proven the critical role of lncRNAs in the occurrence and development of HNSCC by means of epigenetic modifications, regulation of gene transcription, and post-transcription level. More importantly, crosstalk between lncRNAs and microRNAs was recently proven to regulate HNSCC metastasis through EMT modification. Based on these, this review summarizes the critical roles of lncRNAs in HNSCC metastasis and the crosstalk between lncRNAs and microRNAs as well as the detailed regulatory mechanism of the interaction. Thus, a deeper understanding of the lncRNA network in cancer metastasis is finally uncovered in order to provide a rationale and innovative concepts toward new therapeutic strategies for the highly metastatic HNSCC.

Oncogenic roles of lncRNA BLACAT1 and its related mechanisms in human cancers

Long non-coding RNAs (lncRNAs) play indispensable roles in mediating regulation of epigenetics, and their dysregulation is strongly associated with the initiation and progression of human cancers. Recently, lncRNA bladder cancer-associated transcript 1 (BLACAT1) has been observed to exert oncogenic effects on cancers, including glioma, breast cancer, lung cancer, hepatocellular carcinoma, gastric cancer, colorectal cancer, ovarian cancer, cervical cancer and osteosarcoma. Additional mechanical analyses have uncovered that lncRNA BLACAT1 is positively correlated with tumor stage, lymph node metastasis and distant metastasis of primary tumors via involvement with various cellular activities, thus leading to poor overall survival and progression-free survival (PFS). In this review, we generalize the oncogenic roles of BLACAT1 in multiple human cancers through correlation with clinical implications and cellular activities. Moreover, we forecast its potential clinical application as a novel biomarker and a promising therapeutic target for cancers.

Natural antisense transcripts in the biological hallmarks of cancer: powerful regulators hidden in the dark

Natural antisense transcripts (NATs), which are transcribed from opposite strands of DNA with partial or complete overlap, affect multiple stages of gene expression, from epigenetic to post-translational modifications. NATs are dysregulated in various types of cancer, and an increasing number of studies focusing on NATs as pivotal regulators of the hallmarks of cancer and as promising candidates for cancer therapy are just beginning to unravel the mystery. Here, we summarize the existing knowledge on NATs to highlight their underlying mechanisms of functions in cancer biology, discuss their potential roles in therapeutic application, and explore future research directions.

Recent advances of long noncoding RNAs involved in the development of multiple sclerosis

Given the rapid increase of patients with autoimmune diseases and the lack of satisfactory therapies, the discovery of novel and effective therapeutic targets have been in an urgent demand. Recent studies have revealed that long noncoding RNAs (lncRNAs) play crucial roles in the development of multiple sclerosis (MS), which provides a new opportunity of uncovering novel mechanism associated with the progression of MS. This review highlights the dysregulation of lncRNAs in the development of MS in patients and animal models. Additionally, the potential clinical relevance of lncRNAs severed as therapeutic targets and diagnostic markers are discussed.

YRNAs: New Insights and Potential Novel Approach in Head and Neck Squamous Cell Carcinoma

YRNAs are a class of non-coding RNAs that are components of the Ro60 ribonucleoprotein particle and are essential for initiation of DNA replication. Ro60 ribonucleoprotein particle is a target of autoimmune antibodies in patients suffering from systemic lupus erythematosus and Sjögren’s syndrome. Deregulation of YRNAs has been confirmed in many cancer types, but not in head and neck squamous cell carcinoma (HNSCC). The main aim of this study was to determine the biological role of YRNAs in HNSCC, the expression of YRNAs, and their usefulness as potential HNSCC biomarkers. Using quantitative reverse transcriptase (qRT)-PCR, the expression of YRNAs was measured in HNSCC cell lines, 20 matched cancer tissues, and 70 FFPETs (Formaline-Fixed Paraffin-Embedded Tissue) from HNSCC patients. Using TCGA (The Cancer Genome Atlas) data, an analysis of the expression levels of selected genes, and clinical-pathological parameters was performed. The expression of low and high YRNA1 expressed groups were analysed using gene set enrichment analysis (GSEA). YRNA1 and YRNA5 are significantly downregulated in HNSCC cell lines. YRNA1 was found to be significantly downregulated in patients’ tumour sample. YRNAs were significantly upregulated in T4 stage. YRNA1 showed the highest sensitivity, allowing to distinguish healthy from cancer tissue. An analysis of TCGA data revealed that expression of YRNA1 was significantly altered in the human papilloma virus (HPV) infection status. Patients with medium or high expression of YRNA1 showed better survival outcomes. It was noted that genes correlated with YRNA1 were associated with various processes occurring during cancerogenesis. The GSEA analysis showed high expression enrichment in eight vital processes for cancer development. YRNA1 influence patients’ survival and could be used as an HNSCC biomarker. YRNA1 seems to be a good potential biomarker for HNSCC, however, more studies must be performed and these observations should be verified using an in vitro model.

Effects of propofol on colon cancer metastasis through STAT3/HOTAIR axis by activating WIF-1 and suppressing Wnt pathway

BACKGROUND

In the present study, we aim to investigate the potential role of propofol in the tumor progression of colon cancer.

METHODS

Human colon cancer cell lines were cultured and exposed with 8 μg/mL propofol. RNA interference was performed to silence the expression of HOTAIR or STAT3 to explore their biological functions in colon cancer. Cell apoptosis and invasion were assessed using flow cytometry and transwell assays, respectively. Quantitative real-time PCR, western blot, and immunohistochemistry were subjected to measure the expression patterns of HOTAIR, STAT3, Wnt signaling factors, and epithelial-mesenchymal transition-related markers, respectively. Besides, nude mice were transplanted with colon cancer cells for further exploration. Tumor formation, volume, and weight were evaluated to validate the in vitro findings.

RESULTS

Propofol treatment promoted cell apoptosis and inhibited cell invasion in colon cancer cells, while the effects were reversed by HOTAIR overexpression. Additionally, STAT3 positively regulated HOTAIR expression, which was also negatively modulated by propofol. Moreover, STAT3 and HOTAIR were shown to independently regulate colon cancer cell apoptosis and invasion. Furthermore, HOTAIR could stimulate Wnt signaling pathway via inhibiting WIF-1 expression and upregulating β-catenin expression, which was also demonstrated by in vivo study.

CONCLUSION

Taken together, the current study demonstrated that propofol exerts the inhibition on cell invasion and promotion on cell apoptosis through regulating STAT3/HOTAIR by activating WIF-1 and suppressing Wnt pathway, indicating that propofol might serve as a therapeutic role for colon cancer patients in the future.

Long Noncoding RNA DCST1-AS1 Promotes Cell Proliferation and Metastasis in Triple-negative Breast Cancer by Forming a Positive Regulatory Loop with miR-873-5p and MYC

Background: DC-STAMP domain containing 1-antisense 1 (DCST1-AS1) is a long noncoding RNA (lncRNA) that is up-regulated in triple-negative breast cancer (TNBC) tissues. Here, we attempt to investigate the oncogenic property of DCST1-AS1.

Methods: LncRNA microarrays were used to detect differentially expressed lncRNA in cancerous tissues. Fluorescence in situ hybridization assay was used to detect the distribution of DCST1-AS1 in BT-549 and MDA-MB-231 cells. Lentiviral systems, inhibitors, siRNA and overexpression plasmids were used for gain- and loss-of-function experiments. Colony formation assay, wound healing assay, CCK8 assay, transwell assay, and flow cytometry assay were used to study the function of DCST1-AS1. Luciferase assay was used to verify the binding of MYC to the promoter region and the binding of miR-873-5p to DCST1-AS1. RNA immunoprecipitation assay was used to verify that argonaute 2 binds to both miR-873-5p and DCST1-AS1. Western blotting was used to measure changes in protein expression.

Results: Consistent with the microarray results, we found that DCST1-AS1 was up-regulated in both TNBC tissue samples and cell lines. DCST1-AS1 was positively correlated with distant metastasis and histopathological grades. DCST1-AS1 is distributed in both nucleus and cytoplasm. Knockdown of DCST1-AS1 inhibits TNBC cell proliferation and metastasis, while overexpression of DCST1-AS1 promotes TNBC cell proliferation and metastasis. We confirmed that DCST1-AS1 expression in TNBC cells is regulated by MYC. Furthermore, we found that DCST1-AS1 is negatively correlated with miR-873-5p in TNBC tissues and is a direct target gene of miR-873-5p. Argonaute 2 is involved in the binding of DCST1-AS1 and miR-873-5p and promotes the degradation of DCST1-AS1. The interaction of DCST1-AS1 with miR-873-5p ultimately up-regulated the expression of insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1), MYC, CD44 and lymphoid enhancer binding factor 1 (LEF1).

Conclusions:DCST1-AS1 is activated by MYC and is degraded by binding to miR-873-5p, thereby upregulating the expression of miR-873-5p downstream proteins IGF2BP1, MYC, LEF1 and CD44. MYC, DCST1-AS1 and miR-873-5p form a positive regulatory loop to promote TNBC cell proliferation and metastasis.