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

Data Mining Identifies Six Proteins that Can Act as Prognostic Markers for Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a malignant tumor of the upper aerodigestive tract affecting the oral cavity, lips, paranasal sinuses, larynx, and nasopharynx. Proteogenomics combines proteomics and genomics and employs mass spectrometry and high-throughput sequencing technologies to identify novel peptides. The aim of this study was to identify potential protein biomarkers for clinical treatment of HNSCC. To achieve this, we utilized two sets of data, one on proteins from The Cancer Proteome Atlas (TCPA) and the other on gene expression from The Cancer Genome Atlas (TCGA) database, to evaluate dysfunctional proteogenomics microenvironment. Univariate Cox regression analysis was performed to examine the relationship between protein signatures and prognosis. A total of 19 proteins were significantly associated with overall survival (OS) of patients, of which E2F transcription factor 1 (E2F1; HR = 4.557, 95% CI = 1.810 to 11.469) and enhancer of zeste homolog 2 (EZH2; HR = 0.430, 95% CI = 0.187 to 0.984) were the most differentially expressed between patients with longer and shorter OS, respectively. Furthermore, multivariate Cox regression analysis on six proteins (ERALPHA, HER3, BRAF, P27, RAPTOR, and E2F1) was performed to build the prognostic model. The receiver operating characteristic curves were used to determine whether the expression pattern of survival-related proteins could provide an early prediction of the occurrence of HNSCC. Herein, we found an AUC of 0.720. Based on an online database, we identified novel protein markers for the prognosis of HNSCC. The findings of the present study may provide new insights into the development of new and reliable tools for precise cancer intervention.

EZH2 abnormalities in lymphoid malignancies: underlying mechanisms and therapeutic implications

EZH2 is the catalytic subunit of the polycomb repressive complex 2 (PRC2), which along with other PRC2 components mediates gene expression suppression via the methylation of Histone H3 at lysine 27. Recent studies have revealed a dichotomous role of EZH2 in physiology and in the pathogenesis of cancer. While it plays an essential role in the development of the lymphoid system, its deregulation, whether due to genetic or non-genetic causes, promotes B cell- and T cell-related lymphoma or leukemia. These findings triggered a boom in the development of therapeutic EZH2 inhibitors in recent years. Here, we discuss physiologic and pathogenic function of EZH2 in lymphoid context, various internal causes of EZH2 aberrance and how EZH2 modulates lymphomagenesis through epigenetic silencing, post-translational modifications (PTMs), orchestrating with surrounding tumor micro-environment and associating with RNA or viral partners. We also summarize different strategies to directly inhibit PRC2-EZH2 or to intervene EZH2 upstream signaling.

LINC00355 Promotes Tumor Progression in HNSCC by Hindering MicroRNA-195-Mediated Suppression of HOXA10 Expression

Emerging evidence suggests that long non-coding RNAs (lncRNAs) are involved in the progression of head and neck squamous cell carcinoma (HNSCC). However, the specific role of LINC00355 in HNSCC remains elusive. Here, we identify the relationship between LINC00355 and the development of HNSCC through the interaction of LINC00355 with microRNA-195 (miR-195), which in turn targets homeoboxA10 (HOXA10). First, we identified differentially expressed lncRNAs and genes related to HNSCC. Next, the interaction among LINC00355, miR-195, and HOXA10 was identified. Subsequently, the expression of LINC00355 and miR-195 was altered to evaluate their effects on viability, invasion, migration, epithelial mesenchymal transition (EMT), and apoptosis of cancer stem cells (CSCs) in HNSCC. Finally, we assessed the ability of LINC00355 to alter tumor growth after HNSCC CSCs were injected into nude mice. Our findings indicate that LINC00355 and HOXA10 were highly expressed in HNSCC, while miR-195 was poorly expressed. CSCs with upregulated aldehyde dehydrogenase 1 (ALDH-1) were sorted. Silencing LINC00355 in these cells led to increased miR-195 expression and a reduction in HOXA10 expression, which inhibited viability, invasion, migration, and EMT and promoted apoptosis of CSCs. Silencing LINC00355 in vivo also led to decreased tumor growth. Our study provides evidence that LINC00355 acts as a miR-195 sponge to promote viability, invasion, migration, and EMT and inhibit apoptosis of CSCs by upregulating HOXA10, suggesting that LINC00355 represents a potential therapeutic target in the treatment of HNSCC.

Upregulation of the long non-coding RNA CASC9 as a biomarker for squamous cell carcinoma

BACKGROUND

Few diagnostic and prognostic biomarkers are available for head-and-neck squamous cell carcinoma (HNSCC). Long non-coding RNAs (lncRNAs) have shown promise as biomarkers in other cancer types and in some cases functionally contribute to tumor development and progression. Here, we searched for lncRNAs useful as biomarkers in HNSCC.

METHODS

Public datasets were mined for lncRNA candidates. Two independent HNSCC tissue sets and a bladder cancer tissue set were analyzed by RT-qPCR. Effects of lncRNA overexpression or downregulation on cell proliferation, clonogenicity, migration and chemosensitivity were studied in HNSCC cell lines.

RESULTS

Data mining revealed prominently CASC9, a lncRNA significantly overexpressed in HNSCC tumor tissues according to the TCGA RNAseq data. Overexpression was confirmed by RT-qPCR analyses of patient tissues from two independent cohorts. CASC9 expression discriminated tumors from normal tissues with even higher specificity than HOTAIR, a lncRNA previously suggested as an HNSCC biomarker. Specificity of HNSCC detection by CASC9 was further improved by combination with HOTAIR. Analysis of TCGA pan-cancer data revealed significant overexpression of CASC9 across different other entities including bladder, liver, lung and stomach cancers and especially in squamous cell carcinoma (SCC) of the lung. By RT-qPCR analysis we furthermore detected stronger CASC9 overexpression in pure SCC of the urinary bladder and mixed urothelial carcinoma with squamous differentiation than in pure urothelial carcinomas. Thus, CASC9 might represent a general diagnostic biomarker and particularly for SCCs. Unexpectedly, up- or downregulation of CASC9 expression in HNSCC cell lines with low or high CASC9 expression, respectively, did not result in significant changes of cell viability, clonogenicity, migration or chemosensitivity.

CONCLUSIONS

CASC9 is a promising biomarker for HNSCC detection. While regularly overexpressed, however, this lncRNA does not seem to act as a major driver of development or progression in this tumor.

LncRNA PTCSC3 inhibits cell proliferation in laryngeal squamous cell carcinoma by down-regulating lncRNA HOTAIR

It is known that lncRNA PTCSC3 inhibits thyroid cancer and glioma and STAT3 promotes cancer development. We, in the present study, investigated the potential involvement of PTCSC3 in laryngeal squamous cell carcinoma (LSCC) and explored its interactions with STAT3. In the present study, we showed that plasma PTCSC3 was down-regulated in early stage LSCC patients, and the down-regulation of PTCSC3 separated in early stage LSCC patients from control group. LncRNA HOTAIR was up-regulated in early stage LSCC patients and was significantly and inversely correlated with PTCSC3 in LSCC patients. PTCSC3 overexpression led to the inhibition of HOTAIR, while PTCSC3 expression was not significantly affected by HOTAIR overexpression. PTCSC3 overexpression mediated the inhibited, while HOTAIR overexpression mediated the promoted proliferation of LSCC cells. However, cell invasion and migration were not significantly affected by PTCSC3 overexpression. In addition, HOTAIR overexpression reduced the inhibitory effects of PTCSC3 overexpression on cancer cell proliferation. Moreover, PTCSC3 overexpression mediated the down-regulation of STAT3 and STAT3 overexpression mediated the up-regulation of HOTAIR. Therefore, PTCSC3 may negatively interact with HOTAIR through STAT3 to inhibit LSCC cell proliferation.

Emerging role of HOX genes and their related long noncoding RNAs in lung cancer

The transcription factor homeobox (Hox) proteins are the master regulator for the embryonic development. Studies have identified new functions for HOX in the regulation of metabolism and other primary cellular processes in humans. Their dysregulation has been observed in a variety of cancers and accumulating evidence has revealed the crucial role of HOX in cancer progression, metastasis, and resistance to therapy. HOX-related long non-coding RNAs (lncRNAs) became the most attracting lncRNAs recently that play critical role in gene regulation and chromatin dynamics in cancers. In this review, we explore the roles of HOX and their related lncRNAs in lung cancer, indicating HOX genes as potential therapeutic targets in lung cancer.

Overexpression of ZEB2-AS1 promotes epithelial-to-mesenchymal transition and metastasis by stabilizing ZEB2 mRNA in head neck squamous cell carcinoma

The long noncoding RNAs (lncRNAs) have been increasingly appreciated as key players underlying tumourigenesis and hold great potentials as prognostic biomarkers and therapeutic targets. However, their roles in head neck squamous cell carcinoma (HNSCC) have remained incompletely known. Here, we sought to reveal the oncogenic roles and clinical significance of a tumour‐associated lncRNA, zinc finger E‐box binding homeobox 2 antisense RNA 1 (ZEB2‐AS1), in HNSCC. ZEB2‐AS1 was aberrantly overexpressed in a fraction of HNSCC samples. Its overexpression significantly associated with large tumour size, cervical node metastasis and reduced overall and disease‐free survival. Antisense oligonucleotides (ASO)‐mediated ZEB2‐AS1 depletion markedly inhibited cell proliferation, migration and invasion while triggered apoptosis in HNSCC cells in part via modulating ZEB2 mRNA stability. Enforced overexpression of ZEB2 largely attenuated the phenotypic changes resulted from ZEB2‐AS1 inhibition except the impaired cell proliferation. In addition, ZEB2‐AS1 was required for TGF‐β1‐induced epithelial‐mesenchymal transition (EMT) in vitro. Significantly reduced tumour growth and lung metastasis were observed in ZEB2‐AS1‐depleted cells in HNSCC xenograft animal models. Taken together, our findings reveal that overexpression of ZEB2‐AS1 associates with tumour aggressiveness and unfavourable prognosis by serving as a putative oncogenic lncRNA and a novel prognostic biomarker in HNSCC.

VPS33B interacts with NESG1 to modulate EGFR/PI3K/AKT/c-Myc/P53/miR-133a-3p signaling and induce 5-fluorouracil sensitivity in nasopharyngeal carcinoma

The vacuolar protein sorting 33B (VPS33B) was rarely reported in malignant tumors. In this research, we demonstrated that overexpression of VPS33B inhibited proliferation and chemoresistance to fluorouracil (5-FU) in nasopharyngeal carcinoma (NPC) in vivo and in vitro. Mechanistic analysis confirmed that overexpression of VPS33B modulated EGFR/PI3K/AKT/c-Myc/P53 signaling to arrest the cell cycle at G1/S phase. In addition, miR-133a-3p, a tumor-suppressive miRNA, was induced by P53 and directly targeted the EGFR/PI3K/AKT/c-Myc/P53 signaling and thus formed a negative feedback loop. Furthermore, another tumor suppressor, NESG1, interacted with VPS33B by colocalizing in the cytoplasm. The knockdown of NESG1 reversed the inhibitory effects of the overexpression of VPS33B in NPC cells by downregulating the PI3K/AKT/c-Jun-mediated transcription repression. Surprisingly, VPS33B was downregulated in the nicotine-treated and LMP-1-overexpressing NPC cells by targeting PI3K/AKT/c-Jun-mediated signaling. In addition, patients with higher VPS33B expression had a longer overall survival. Our study is the first to demonstrate that VPS33B is negatively regulated by LMP-1 and nicotine and thus suppresses the proliferation of NPC cells by interacting with NESG1 to regulate EGFR/PI3K/AKT/c-Myc/P53/miR-133a-3p signaling in NPC cells.

VPS33B interacts with NESG1 to modulate EGFR/PI3K/AKT/c-Myc/P53/miR-133a-3p signaling and induce 5-Fluorouracil sensitivity in nasopharyngeal carcinoma, and VPS33B was inhibited by LMP-1 and nicotine.

p53-targeted lincRNA-p21 acts as a tumor suppressor by inhibiting JAK2/STAT3 signaling pathways in head and neck squamous cell carcinoma

Background

Long intergenic noncoding RNA p21 (lincRNA-p21) is considered a target of wild-type p53, but little is known about its regulation by mutant p53 and its functions during the progression of head and neck squamous cell carcinoma (HNSCC).

Methods

RNAscope was used to detect the expression and distribution of lincRNA-p21. Chromatin immunoprecipitation and electrophoretic mobility shift assays were performed to analyze the transcriptional regulation of lincRNA-p21 in HNSCC cells. The biological functions of lincRNA-p21 were investigated in vitro and in vivo. RNA immunoprecipitation and pull-down assays were used to detect the direct binding of lincRNA-p21.

Results

Lower lincRNA-p21 expression was observed in HNSCC tissues and indicated worse prognosis. Both wild and mutant type p53 transcriptionally regulated lincRNA-p21, but nuclear transcription factor Y subunit alpha (NF-YA) was essential for mutant p53 in the regulation of lincRNA-p21. Ectopic expression of lincRNA-p21 significantly inhibited cell proliferation capacity in vitro and in vivo and vice versa. Moreover, the overexpression of lincRNA-p21 induced G1 arrest and apoptosis. Knockdown NF-YA expression reversed tumor suppressor activation of lincRNA-p21 in mutant p53 cells, not wild-type p53 cells. A negative correlation was observed between lincRNA-p21 and the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) in HNSCC tissues. High lincRNA-p21 expression inhibited Janus kinase 2 (JAK2)/STAT3 signal activation and vice versa. Further, we observed direct binding to STAT3 by lincRNA-p21 in HNSCC cells, which suppressed STAT3-induced oncogenic potential.

Conclusions

Our results revealed the transcriptional regulation of lincRNA-p21 by the mutant p53/NF-YA complex in HNSCC. LincRNA-p21 acted as a tumor suppressor in HNSCC progression, which was attributed to direct binding to STAT3 and blocking of JAK2/STAT3 signaling.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0993-3) contains supplementary material, which is available to authorized users.

Analysis of lncRNA-Mediated ceRNA Crosstalk and Identification of Prognostic Signature in Head and Neck Squamous Cell Carcinoma

Long non-coding RNA (lncRNA) can act as ceRNA to regulate the expression of target genes by sponging miRNAs, and therefore plays an essential role in tumor initiation and progression. However, functional roles and regulatory mechanisms of lncRNAs as ceRNAs in head and neck squamous cell carcinoma (HNSCC) remain to be determined. We downloaded RNA sequence profiles from The Cancer Genome Atlas (TCGA) database, and identified the differential RNAs by bioinformatics. Then we analyzed the biological processes of differential expressed RNAs (DER), and established their interaction networks and pathway analysis to find out potential biological effects of these DERs. Besides, we also explored the relationship between the DERs and prognosis of HNSCC patients. We obtained 525 tumor samples and 44 paracancerous controls, and there were 1081 DElncRNAs, 1889 DEmRNAs, and 145 DEmiRNAs. GO and KEGG pathways analysis of these DEmRNAs were mainly involved in "Protein digestion and absorption," "Calcium signaling pathway," and "ECM-receptor interaction." The analysis of the ceRNA network identified 61 DElncRNAs as functional ceRNAs whose dysregulated expression may affect the expression of oncogenes/tumor suppressor genes. Furthermore, univariate and multivariate Cox regression analysis revealed that 4 DElncRNAs, 3 EDmiRNAs, and 6 DEmRNAs can predict survival with high accuracy. Survival analysis found that 4 lncRNAs was related to prognostic, including overexpressed RP11-366H4.1, HOTTIP, RP11-865I6.2, and RP11-275N1.1 patients had a worse survival. In conclusion, through constructing the ceRNA network in HNSCC patients, we identified key lncRNA-miRNA-mRNA network in HNSCC. All the DERs might participate in varieties of pathways in the initiation, progression, and invasion of HNSCC. Furthermore, some miRNAs (hsa-mir-99a, hsa-mir-337, and hsa-mir-137) and mRNAs (NOSTRIN, TIMP4, GRB14, HOXB9, CELSR3, and ADGRD2) may be the prognostic genes of HNSCC. This study provided a new target and theoretical basis for further research on molecular mechanisms and biomarkers.

SP1-induced upregulation of long non-coding RNA HCP5 promotes the development of osteosarcoma

Long non-coding RNAs (LncRNAs) are acknowledged as crucial regulators in tumorigenesis and tumor progression. In this study, we explored the mechanism and function of lncRNA HCP5 in osteosarcoma (OS). At first, five lncRNAs were chosen from GeneCard and subjected to qRT-PCR examination. The results indicated that HCP5 was significantly overexpressed in four OS cell lines. Northern blot assay further proved the higher expression of HCP5 in OS cell lines. To identify the biological role of HCP5 in OS, we silenced the expression of HCP5 in U2OS and MG-63 cells which possessed the highest level of HCP5. CCK-8 and colony formation assay revealed the inhibitory effect of HCP5 knockdown on cell proliferation. Cell apoptosis was found to be increased in cells transfected with sh-HCP5#1. Moreover, cell invasion and epithelial-mesenchymal transition (EMT) were reversed by the silencing of HCP5. The results of functional assays showed that HCP5 acted as an oncogene in osteosarcoma. Mechanically, HCP5 was found to be activated by the transcription factor SP1. Finally, rescue assays were conducted to demonstrate the function of SP1/HCP5 axis in osteosarcoma. In conclusion, we confirmed that SP1-induced upregulation of long non-coding RNA HCP5 promotes the development of osteosarcoma.

STAT3-induced upregulation of lncRNA ABHD11-AS1 promotes tumour progression in papillary thyroid carcinoma by regulating miR-1301-3p/STAT3 axis and PI3K/AKT signalling pathway

Objectives

Emerging evidences indicated the importance of long non‐coding RNAs (lncRNAs) in the tumorigenesis and deterioration of malignant tumours. To our knowledge, the study about lncRNAs in papillary thyroid carcinoma (PTC) is still inadequate. ABHD11‐AS1 was highly expressed in the PTC samples of The Cancer Genome Atlas database. This study focused on the biological function and mechanism of lncRNA ABHD11‐AS1 in PTC.

Materials and methods

qRT‐PCR analysis was used to examine the expression of ABHD11‐AS1 in PTC tissues and cell lines. The prognostic significance of ABHD11‐AS1 for the patients with PTC was analysed with Kaplan‐Meier analysis. The effects of ABHD11‐AS1 knockdown on the cell proliferation and metastasis were evaluated by in vitro functional assays and in vivo experiments. The molecular mechanism which contributed to the oncogenic role of ABHD11‐AS1 in PTC was explored by conducting mechanism experiments. Rescue assays were carried out for final demonstration.

Results

High expression of ABHD11‐AS1 predicted poor prognosis for patients with PTC and promoted cell proliferation and metastasis in vitro and in vivo. ABHD11‐AS1 was activated by the transcription factor STAT3. ABHD11‐AS1 positively regulated PI3K/AKT signalling pathway. ABHD11‐AS1 acted as a competitive endogenous (ce) RNA to upregulate STAT3 by sponging miR‐1301‐3p.

Conclusions

STAT3‐induced lncRNA ABHD11‐AS1 promoted PTC progression by regulating PI3K/AKT signalling pathway and miR‐1301‐3p/STAT3 axis.

ELK1-induced upregulation of long non-coding RNA MIR100HG predicts poor prognosis and promotes the progression of osteosarcoma by epigenetically silencing LATS1 and LATS2

Osteosarcoma (OS) is the commonest malignant bone tumor in the world. High incidence of OS has gradually become a social problem. Recent years, numerous studies have revealed that long non-coding RNAs (lncRNAs) are crucial regulators in the tumor progression. As a member of lncRNA family, MIR100HG has been reported to be an oncogene in breast cancer and acute megakaryoblastic leukemia. Nevertheless, the specific role of MIR100HG in osteosarcoma is still unclear. In this study, we investigated the biological function and molecular mechanism of MIR100HG in the progression of osteosarcoma. At first, we measured the high expression of MIR100HG in OS tissues and cell lines by qRT-PCR. Kaplan-Meier method revealed that high expression of MIR100HG is a factor for the poor prognosis of OS patients (P = 0.004). To explore the effect of MIR100HG on the biological processes of OS, loss-of-function assays were conducted in OS cells. Functionally, MIR100HG knockdown suppressed cell proliferation, cell cycle progression while promoted cell apoptosis. Mechanistically, MIR100HG was upregulated by the transcription factor ELK1. The upregulation of MIR100HG led to the inactivation of Hippo pathway. Furthermore, we found that MIR100HG inactivated Hippo pathway in OS cells by epigenetically silencing LATS1 and LATS2. Rescue assays demonstrated that LATS1/2 involved in MIR100HG-mediated OS progression. In summary, our study indicated that ELK1-induced upregulation of MIR100HG promoted OS progression by epigenetically silencing LATS1 and LATS2 and inactivating Hippo pathway.

LncRNA PVT1 promotes malignant progression in squamous cell carcinoma of the head and neck

Long non-coding RNAs (lncRNAs) are potentially critical regulators of cancer malignant behaviours. Aberrant expression and dysfunction of lncRNA PVT1 have been reported in multiple human cancers. However, its role in squamous cell carcinoma of the head and neck (SCCHN) remains largely unknown. Our current study demonstrated that PVT1 expression was increased in SCCHN. High PVT1 expression was positively correlated with SCCHN clinical parameters including T classification, clinical stages and cervical lymph node metastasis. More importantly, high PVT1 expression predicted a poor prognosis in SCCHN patients. Gain-of function and loss-of function studies further indicated that PVT1 promoted the proliferation and invasion of SCCHN both in vitro and in vivo, which was accompanied by epithelial-mesenchymal transition and enhanced cancer stem cell-like properties. Further mechanistic investigation revealed that PVT1 activated Wnt/β-catenin signalling pathway, and inhibition of Wnt/β-catenin signalling reversed the malignant progression caused by PVT1 overexpression. Together, our study reveals that PVT1 accelerates the malignant progression of SCCHN and represents a potential biomarker and therapeutic target in SCCHN.

Anti-tumor effect of HOTAIR-miR-613-SNAI2 axis through suppressing EMT and drug resistance in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC) is the main pathological type of laryngeal cancer, which attacks the head and neck. Our present study aims to investigate the effect of long non-coding RNA (LncRNA) HOX transcript antisense RNA (HOTAIR) on epithelial mesenchymal transition (EMT) and drug resistance in LSCC. Firstly, the level of HOTAIR was found to be overexpressed in LSCC tissues compared with normal healthy tissues. Then, increased EMT and drug resistance were suppressed by specific HOTAIR shRNA effectively in LSCC cell lines. Besides, miR-613 was predicted to be a target of HOTAIR through bioinformatics analysis. Meanwhile, we found that a down-regulated level of miR-613 could be increased by HOTAIR shRNA and suppressed by LncRNA HOTAIR transfection in LSCC cells. The targeting relationship between miR-613 and HOTAIR was further demonstrated by a luciferase report assay. What is more, the inhibiting effect of HOTAIR shRNA on EMT and drug resistance was obviously abolished by the miR-613 inhibitor. Moreover, SNAI2, a critical regulator of EMT, was predicted as a target of miR-613 through bioinformatics analysis and luciferase report assays. As expected, the level of SNAI2 could be suppressed by HOTAIR shRNA and increased by the miR-613 inhibitor. Additionally, we discovered that SANI2 shRNA had similar inhibiting effect on EMT and drug resistance with HOTAIR shRNA in LSCC cells. Finally, the in vivo experiment further demonstrated that HOTAIR shRNA restricted tumor growth, EMT and drug resistance. Additionally, HOTAIR shRNA transfection could also increase the level of miR-613 and decrease the level of SNAI2 in vivo. Taken together, our research for the first time revealed the effect of the HOTAIR-miR-613-SNAI2 axis on EMT and drug resistance in LSCC, providing new targets for LSCC diagnosis and treatment.