Invasion Of Head And Neck Squamous Cell Carcinoma Cells Research Articles

DOT1L Epigenetically Induces the Expression Level of FoxM1 through H3K79me2 and Affects the Malignant Behaviors of Head and Neck Squamous Cell Carcinoma Cells

DOT1-like histone lysine methyltransferase (DOT1L) has been revealed to be highly correlated with progression of diverse types of cancer, while its role in head and neck squamous cell carcinoma (HNSCC) has still remained elusive. In this study, it was found that DOT1L was highly expressed in HNSCC tissues and cell lines, and its high expression level was closely associated with poor prognosis, tumor differentiation, T stage, and pathological stage of HNSCC patients. With the introduction of DOT1L inhibitors, SGC 0946, DOT1L inhibition significantly suppressed proliferation, migration, and invasion of HNSCC cells, while increased their apoptosis rate. To investigate the fundamental mechanism, we predicted that the expression level of Forkhead Box M1 (FoxM1) was positively correlated with DOT1L, and it was found that the expression level of FoxM1 was upregulated in HNSCC tissues and cell lines. Importantly, DOT1L activated FoxM1 through H3K79me2, and inhibition of DOT1L repressed the malignant behaviors of HNSC cells, which could be rescued by FoxM1 overexpression. Taken together, the results suggested that DOT1L could epigenetically induce the expression level of FoxM1 through H3K79me2 and affected the malignant behaviors of HNSCC cells, which could provide novel outcomes for the therapy of HNSC.

Specificity protein 1/microRNA-92b forms a feedback loop promoting the migration and invasion of head and neck squamous cell carcinoma

ABSTRACT In this study we report a novel specificity protein 1 (SP1)/microRNA-92b (miR-92b) feedback loop regulating the migration and invasion of head and neck squamous cell carcinoma (HNSCC). Microarray and real-time Polymerase Chain Reaction (PCR) were used to detect gene expression in HNSCC tissues and cell lines. Transwell migration, invasion, wound healing and cell counting kit – 8 (CCK-8) cell assays were used to compare cell migration, invasion and proliferation abilities. Chromatin Immunoprecipitation (ChIP) assays were used to detect SP1 binding to the miR-92b promoter. Western blot was used to detect protein levels. An in vivo tumorigenesis experiment was used to evaluate the effect of SP1 knockdown on tumor growth and protein levels were evaluated by immunohistochemistry. We found that the miR-92b expression level was elevated in HNSCC primary focus tissue compared with adjacent normal tissue, and a higher level of miR-92b was related to a higher clinical stage and worse prognosis of HNSCC patients. MiR-92b and SP1 mutually promoted each expression and cooperatively facilitated the migration, invasion and proliferation of HNSCC cells. A decreased level of SP1/miR-92b resulted in a restraint of in vivo tumor growth. In conclusion, our results suggest that the SP1/miR-92b feedback loop generally promotes HNSCC invasion and metastasis, thus presenting a possible therapeutic target in the treatment of HNSCC patients.

Identification and in vitro validation of prognostic lncRNA signature in head and neck squamous cell carcinoma

ABSTRACT Long non-coding RNAs (lncRNAs) are promising cancer prognostic markers. However, the clinical significance of lncRNA signatures in evaluating overall survival (OS) outcomes of head and neck squamous cell carcinoma (HNSCC) has not been explored. This study aimed to assess the significance of lncRNA in HNSCC and to develop a lncRNA signature related to OS in HNSCC. LncRNA expression matrices were retrieved from the Cancer Genome Atlas (TCGA) data. Least Absolute Shrinkage and Selection of the Operator (LASSO), univariate and multivariate Cox regression were used for establishing a prognostic model. In vitro experiments were carried out to demonstrate the biological role of lncRNA. A prognosis model based on 7 DElncRNAs was finally established.The patients were then divided into high-risk and low-risk groups. Relative to the low-risk group, overall survival times for patients in the high-risk group were significantly low (P=2.466e−07). Risk score remained an independent prognostic factor in univariate (HR=1.329, 95%CI=1.239−1.425, p < 0.001) and multivariate (HR=1.279, 95%CI=1.184−1.382, p < 0.001) Cox regression analyses. The area under the curve (AUC) of the signature was as high as 0.78. Expressions of FOXD2-AS1 in tumor tissues were elevated, and significantly correlated with OS (P=0.008). FOXD2-AS1 silencing then significantly reduced HNSCC cell proliferation, invasion, and migration. In conclusion, a lncRNA signature was established for HNSCC prognostic prediction and FOXD2-AS1 was identified as an HNSCC oncogene.

Phosphorylation of MICAL2 by ARG promotes head and neck cancer tumorigenesis by regulating skeletal rearrangement.

The actin cytoskeletal architecture provides the structural underpinnings for crucial cellular behaviors. In cancer cells, changes in the actin cytoskeleton may serve as prerequisites for proliferation, invasion, and metastatic dissemination. However, the underlying mechanisms remain largely unknown. Here, we show that MICAL2, which is increased in head and neck squamous cell carcinoma (HNSCC) and inversely associated with patient survival, promotes HNSCC growth, invasion, and migration. MICAL2 serves as a flavoprotein monooxygenase and directly induces actin filament depolymerization by specifically oxidizing the methionine 44 and 47 residues of F-actin. The kinase ARG interacts with MICAL2 and augments MICAL2-mediated actin disassembly. Direct phosphorylation assay and mass spectrometry confirmed that ARG phosphorylates MICAL2 at Tyr445, Tyr463, and Tyr488. Substitution of the Tyr445 or Tyr463 residue of purified recombinant MICAL2-redox with phenylalanine (generating a non-phosphorylatable mutant) abolishes the enhanced MICAL2-mediated F-actin disassembly induced by ARG. Consistently, ectopic expression of non-phosphorylatable MICAL2 mutants (MICAL2Y445F and MICAL2Y463F, not MICAL2Y488F) failed to ameliorate HNSCC cell growth, whereas expression of wild-type MICAL2 or MICAL2Y488F rescued the impaired proliferation induced by MICAL2 knockdown. Moreover, CCG-1423, an inhibitor of MICAL2, was shown to inhibit HNSCC cell proliferation, invasion, and migration. Taken together, our findings indicate that phosphorylation of MICAL2 at Tyr445 and Tyr463 by ARG mediates F-actin disassembly and promotes HNSCC progression.

FOXM1 Promotes Head and Neck Squamous Cell Carcinoma via Activation of the Linc-ROR/LMO4/AKT/PI3K Axis.

Background/AimPrevious literature has implicated the sustained expression of FOXM1 in numerous human cancers, including head and neck squamous cell carcinoma (HNSCC). The current study aimed to elucidate the function and regulatory mechanism of FOXM1 in HNSCC.MethodsWestern blot and RT-qPCR methods were performed to evaluate the expression of Linc-ROR, FOXM1, and LMO4 in HNSCC tissue samples and cells. The binding between FOXM1 and Linc-ROR was analyzed using a ChIP assay. Various cellular processes including proliferation and invasion abilities were assessed following alteration of FOXM1, Linc-ROR and LMO4 expression in HNSCC cells. Xenograft mouse models were established to validate the in vitro findings.ResultsLinc-ROR and FOXM1 were highly expressed in HNSCC tissues and cells. FOXM1 operated as a potential transcription factor to bind to the promoter region of Linc-ROR. Linc-ROR and FOXM1 exhibited high expression levels in both the clinical tissue samples as well as the HNSCC cells, which could facilitate the proliferation and invasion of HNSCC cells. Linc-ROR upregulated the expression of LMO4 and promoted activation of the AKT/PI3K signaling pathway, thus stimulating the proliferation and invasion of HNSCC cells. Silencing of Linc-ROR brought about a contrasting effect relative to that seen when FOXM1 was overexpressed in HNSCC in vivo.ConclusionsOverall, FOXM1 promoted the expression of Linc-ROR and induced the activation of the LMO4-dependent AKT/PI3K signaling pathway, thus facilitating the occurrence and development of HNSCC.

Long non‑coding RNA MIR4435‑2HG promotes the progression of head and neck squamous cell carcinoma by regulating the miR‑383‑5p/RBM3 axis.

Recent studies have shown that long non-coding RNAs (lncRNAs) are strongly related to the progression of various types of cancer. The lncRNA MIR4435-2 host gene (MIR4435-2HG) has been recently recognized as a tumor-related lncRNA that is upregulated in several tumors. However, its possible functions in head and neck squamous cell carcinoma (HNSCC) remain unclear. In tShe present study, we observed that MIR4435-2HG expression was markedly upregulated in HNSCC tissues based on a Gene Expression Profiling Interactive Analysis dataset. This result was further confirmed in HNSCC tissues and cell lines using quantitative real-time polymerase chain reaction. In addition, the high expression level of MIR4435-2HG was significantly associated with poor disease-free survival and overall survival in all HNSCC cases and was associated with advanced tumor-metastasis-node stage and poor prognosis. In vitro and in vivo assays demonstrated that MIR4435-2HG knockdown suppressed HNSCC cell proliferation and invasion, epithelial-mesenchymal transition (EMT), and tumor growth as determined by Cell Counting Kit-8, Transwell assays and western blotting. Furthermore, MIR4435-2HG affected HNSCC cell proliferation and migration and EMT by modulating the microRNA miR-383-5p to positively regulate the protein expression level of RNA-binding motif protein 3 (RBM3). In conclusion, we provide a detailed analysis of the roles of MIR4435-2HG in HNSCC and identified the MIR4435-2HG/miR-383-5p/RBM3 axis as a potential therapeutic target for HNSCC treatment.

Inhibitor of DNA Binding 2 (ID2): A Novel Marker for Lymph Node Metastasis in Head and Neck Squamous Cell Carcinoma.

Although aggressive invasion and sequential lymph node metastasis (LNM) significantly affect the prognosis of patients with head and neck squamous cell carcinoma (HNSCC), studies on identifying the factors that regulate this process remain scarce. This study found an inhibitor of DNA binding 2 (ID2) as a novel molecule involved in the regulation of invasion and LNM of HNSCC and further verified its functional role. The study examined the translational significance between ID2 expression levels and the presence of LNM as well as the prognosis for 119 patients with HNSCC after treatment. In addition, in vitro and in vivo experiments were performed using ID2 gene-modulated HNSCC cell lines to determine the functional role of ID2 in the invasion and LNM of HNSCC. Elevated levels of ID2 expression were closely associated with the presence of LNM in 119 patients with HNSCC, resulting in a poor prognosis. Overexpression of ID2-induced invasion and LNM of HNSCC cells was observed in vitro and in vivo. By contrast, knockdown of the ID2 gene diminished invasion and LNM of HNSCC cells. In addition, the ID2 expression level increased the expression level of matrix metalloproteinase 1 (MMP1), a molecule downstream to ID2. Furthermore, silencing of MMP1 in ID2-overexpressed HNSCC cells rescued the elevated invasion and LNM capabilities of these cells, suggesting that ID2 enhances invasion and LNM partly via MMP1 activation. In the invasion and LNM of HNSCC, ID2 plays an important role by modulating MMP1 expression, suggesting ID2-MMP1 axis to be a novel alternative therapeutic target for invasion and LNM of HNSCC.

PLAU1 Facilitated Proliferation, Invasion, and Metastasis via Interaction With MMP1 in Head and Neck Squamous Carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignant neoplasm; it is associated with high morbidity and mortality. Thus, understanding the molecular mechanisms underlying its initiation and progression is critical for establishing the most appropriate treatment strategies. We found that urokinase-type plasminogen activator (PLAU1) was upregulated and associated with poor prognosis in HNSCC. Silencing of PLAU1 inhibited the proliferation, colony-formation, migration, and invasion abilities of HNSCC cells in vitro and reduced the expression of matrix metalloproteinase 1 (MMP1), whereas PLAU1 overexpression significantly enhanced the growth, the colony-formation, migration, and invasion abilities, and the xenograft tumor growth of HNSCC cells in vivo and increased the expression of MMP1. The Co-IP assay verified that PLAU1 interacted with MMP1. A positive correlation between PLAU1 and MMP1 expression was observed in HNSCC samples. si-RNAs against MMP1 reversed the aggressive effects of PLAU1 overexpression in HNSCC. Taken together, our data revealed that PLAU1 facilitated HNSCC cell proliferation, invasion, and metastasis via interaction with MMP1.

LINC00460 Promotes Cell Proliferation, Migration, Invasion, and Epithelial-Mesenchymal Transition of Head and Neck Squamous Cell Carcinoma via miR-320a/BGN Axis.

PurposeLong non-coding RNAs (lncRNAs) play critical roles in cancer onset and development, including head and neck squamous cell carcinoma (HNSCC). This study aimed to investigate the biological role of LINC00460 and the mechanisms underlying epithelial-mesenchymal transition (EMT) in HNSCC.MethodsAberrantly LINC00460 expression in HNSCC and overall survival outcomes were constructed using the TCGA database. Quantitative real-time polymerase chain reaction (RT-qPCR) was applied to examine the LINC00460 expression level in HNSCC cell lines. The role of LINC00460 knockdown on HNSCC cell growth, migration, invasion, and EMT was investigated in vitro using cell counting kit-8 (CCK-8), colony formation, transwell assay, and Western blot assay. Besides, bioinformatics prediction, dual-luciferase reporter assay, and RNA immunoprecipitation (RIP) were performed to reveal the interaction among LINC00460 and its target genes. The function of the LINC00460/miR-320a/BGN axis in HNSCC cells was clarified by rescue assays. Furthermore, the in vivo effects of LINC00460 on tumor growth were investigated using mice xenograft models.ResultsIn this study, LINC00460 was upregulated in HNSCC tissues and cells and was associated with poor clinical prognosis. Further functional analysis showed that LINC00460 knockdown decreased HNSCC cell proliferation, migration, invasion, as well as EMT in vitro. Mechanistic investigation indicated that LINC00460 sponged miR-320a to upregulate Biglycan (BGN) expression, thereby facilitating HNSCC progression and induced EMT. Moreover, knockdown of LINC00460 significantly suppressed the progression of HNSCC cells in vivo.ConclusionTaken together, LINC00460 mediates miR-320a/BGN signaling axis to promote cell proliferation, migration, invasion, and induce the EMT process in HNSCC cells. Our findings elucidated a novel mechanism underlying the progression of HNSCC. LINC00460 could serve as a potential therapeutic target for the treatment of HNSCC.

Wnt/β-catenin/Slug pathway contributes to tumor invasion and lymph node metastasis in head and neck squamous cell carcinoma.

The canonical Wnt/β-catenin pathway is involved in diverse cancer development mechanisms, such as proliferation, migration, and invasion. However, its role in head and neck squamous cell carcinoma (HNSCC) remains largely unknown. We investigated whether the canonical Wnt/β-catenin signaling pathway acts as a controller of invasion and lymph node metastasis (LNM) in HNSCC. Loss of function experiments against the canonical Wnt/β-catenin pathway were conducted to evaluate its invasive and metastatic role in HNSCC cells. Slug was evaluated as a downstream protein in canonical Wnt/β-catenin-mediated invasion. In addition, canonical Wnt/β-catenin and Slug expression levels were examined in 119 HNSCC tissue samples to study the relevance of these proteins in LNM and prognosis of patients post-treatment. In vitro suppression of β-catenin expression led to decreased migration and invasion of HNSCC cells. Using an in vivo mouse orthotopic LNM model, a decrease in LNM was observed with mitigated β-catenin expression. Slug expression upregulation mediates invasion and LNM by the canonical Wnt/β-catenin pathway. Simultaneous expression of β-catenin and Slug is the major predictive factor of LNM and survival rate in patients with HNSCC. In conclusion, the canonical Wnt/β-catenin/Slug signaling axis significantly contributes to cancer cell invasion and LNM. Its blockade may be a treatment strategy for LNM and tumor recurrence in HNSCC.

Cancer-Associated Fibroblast Subgroups Showing Differential Promoting Effect on HNSCC Progression.

Simple SummaryIt is generally accepted that fibroblasts represent a heterogeneous population of cells with different functions depending on the cell type. Although numerous reports have stated that cancer-associated fibroblast (CAF) promotes cancer progression, few studies have shown that they inhibit cancer progression. We propose that CAFs derived from some HNSCC patients is less effective in promoting cancer progression than CAFs from other patients and that specific collagen proteins may be involved in this process.Background: The critical effect of the tumor microenvironment on cancer progression is well recognized. Recent research suggests that the cancer-promoting properties of the tumor stroma may be attributed to fibroblasts. However, the effect of cancer-associated fibroblast (CAF) on the progression of head and neck squamous cell carcinoma (HNSCC) is not well known. Methods: From the immunohistochemical analysis of head and neck squamous cell carcinoma (HNSCC) tissues, we divided CAF into two groups depending on the presence or absence of a well-demarcated boundary between epithelial cancer cells and the surrounding extracellular matrix (ECM). Primary culture of CAF was performed, followed by co-transplantation with HNSCC cells into mice oral mucosa, and the tumorigenesis was compared. The mRNA expression patterns between these two CAF groups were compared using DNA microarray analysis. Results: CAFs from cancer tissues that showed no demarcation between ECM and epithelial cancer cells (CAF-Promote) tended to stimulate Matrigel invasion of HNSCC cells. Conversely, CAFs from cancer tissues that showed a boundary with epithelial cancer cells (CAF-Delay) caused no remarkable increase in Matrigel invasion. Compared with CAF-P, CAF-D is less effective in promoting FaDu tumorigenicity in the mouse model. In DNA microarray analysis, COL3A1 and COL6A6 showed particularly high expression in the CAF-D group. Conclusions: These cancer stroma-derived collagen proteins might delay the HNSCC progression. These findings are expected to provide vital information for predicting HNSCC prognosis and developing drug targets in the future.

Upregulated miR‑411‑5p levels promote lymph node metastasis by targeting RYBP in head and neck squamous cell carcinoma.

Metastasis is the primary cause of the high mortality rates in head and neck squamous cell carcinoma (HNSCC). MicroRNA (miR)-411-5p has been discovered to serve an important role in cancer metastases. However, to the best of our knowledge, the association between miR-411-5p expression levels and HNSCC metastasis has not been thoroughly investigated. The present study aimed to research the function of miR-411-5p in HNSCC metastasis. The results of the present study revealed that miR-411-5p expression levels were upregulated in patients with HNSCC with lymph node metastasis and the upregulated expression levels of miR-411-5p were positively associated with the metastatic potential of HNSCC. Moreover, miR-411-5p promoted HNSCC cell migration, invasion and epithelial-mesenchymal transition (EMT). The results of the dual-luciferase reporter assays identified RING1 and YY1 binding protein (RYBP) as a functional downstream target gene for miR-411-5p. Therefore, whether miR-411-5p downregulated the expression levels of RYBP in HNSCC cells was subsequently investigated. Notably, the silencing of RYBP expression restored the stimulatory effects of miR-411-5p on HNSCC cell migration, invasion and EMT. In addition, the mRNA expression levels of miR-411-5p and RYBP were found to be inversely correlated in HNSCC samples. In conclusion, the results of the present study indicated that the miR-411-5p-mediated downregulation of RYBP expression levels may exert an important role in HNSCC metastasis and may provide a novel target for the treatment of HNSCC.

Long non-coding RNA LINC01296 acts as a migration and invasion promoter in head and neck squamous cell carcinoma and predicts poor prognosis

ABSTRACT Long non-coding RNA (lncRNAs) can participate in gene expression regulation. LINC01296 is abnormally expressed in different tumors and promotes tumorigenesis and development. However, the role of LINC01296 in head and neck squamous cell carcinoma (HNSCC) remains not entirely clear. Thus, to explore LINC01296 expression, biological function and potential mechanism in HNSCC, we used GEPIA and GEO database. QRT-PCR was used to detect the knockout efficiency by LINC01296 inhibition with siRNA. Transwell assay was used to detect the migration and invasion capacity of tumor cells. Then enrichment and immunophenotype correlation analyses were carried out to explore the LINC01296 mechanism in HNSCC. To investigate why LINC01296 was up-regulated in HNSCC, DNA methylation analysis was performed using the DiseaseMeth database. LINC01296 expression was notably up-regulated in HNSCC, which was associated with promoter hypomethylation. Also, it was positively correlated with the HNSCC pathological stage and patients with higher LINC01296 expression levels had a poor prognosis. LINC01296 silencing inhibits HNSCC cell migration and invasion. LINC01296 also participate in the HNSCC progression mainly through protein phosphorylation and microtubule-based process regulation. Overall, LINC01296 was highly expressed in HNSCC, promoted tumor cells’ migration and invasion, and might be a potential diagnostic and prognostic marker in HNSCC patients.

Elevated RUNX1 is a prognostic biomarker for human head and neck squamous cell carcinoma.

Runt-related transcription factors regulate many developmental processes such as proliferation and differentiation. In this study, the function of the runt-related transcription factor 1 (RUNX1) was investigated in head and neck squamous cell carcinoma (HNSCC). Our results show that RUNX1 expression was elevated in HNSCC patients, which was greatly correlated with the N stage, tumor size, and American Joint Committee on Cancer stage. Cox proportional hazard models showed that RUNX1 could be used as a prognostic indicator for the overall survival of HNSCC patients (hazard ratio, 5.572; 95% confidence interval, 1.860-9.963; P < 0.001). Moreover, suppression of RUNX1 inhibited HNSCC cell proliferation, migration, and invasion. Using the HNSCC xenograft nude mouse model, we found that the shRUNX1-transfected tumor (sh-RUNX1) was significantly smaller both in size and weight than the control vector-transfected tumor (sh-Control). In conclusion, our results show that the elevated RUNX1 expression was correlated with tumor growth and metastasis in HNSCC, indicating that RUNX1 could be used as a biomarker for tumor recurrence and prognosis.

Crosstalk between head and neck cancer cells and lymphatic endothelial cells promotes tumor metastasis via CXCL5-CXCR2 signaling.

Head and neck squamous cell carcinoma (HNSCC) metastasizes to the locoregional lymph nodes at high rates and is related to poor clinical outcomes. However, the mechanism by which cancer cells migrate to the lymph nodes is unclear. To address this, we established a conditioned medium culture system for HNSCC cells and lymphatic endothelial cells (LECs) and investigated their crosstalk. Stimulation with tumor-conditioned medium (TCM) activated LECs, resulting in a robust increase in cell proliferation to induce lymphatic hyperplasia. Further, stimulation of HNSCC cells with activated LEC Conditioned media (TCM-LEC CM) induced cell invasion. Among various chemokines, CXCL5 promoted the invasion of TCM-LEC CM-treated HNSCC cells. The level of CXCL5 protein was higher in cancer tissues than those in normal tissues from HNSCC patients. Furthermore, treatment with SB225002, a CXCR2 (CXCL5 receptor) inhibitor, resulted in decreased lymph node metastasis in vivo. In conclusion, inhibition of CXCL5-CXCR2 signaling between cancer cells and LECs suppresses cancer cell invasion and metastasis in vitro and in vivo. This novel therapeutic strategy might be a practical approach to the clinical management of HNSCC.

Combined proteomic and transcriptomic approaches reveal externalized keratin 8 as a potential therapeutic target involved in invasiveness of head and neck cancers.

Keratin 8 (K8) expressed at the surface of cancer cells, referred as externalized K8 (eK8), has been observed in a variety of carcinoma cell lines. K8 has been previously reported to be expressed in poorly differentiated head and neck squamous cell carcinoma (HNSCC); however, its role during the invasive phase of upper aerodigestive tract tumorigenesis is unknown. Cohorts of HNSCC tumors for protein and mRNA expression and panel of cell lines were used for investigation. K8 was found to be externalized in a majority of HNSCC cell lines. Among the two main K8 protein isoforms only the 54 kDa was found to be present at the plasma membrane of HNSCC cells. The plasminogen-induced invasion of HNSCC cells was inhibited by the anti-eK8 D-A10 antagonist monoclonal antibody. Overexpression of K8 mRNA and protein were both correlated with tumor aggressive features and poor outcome. The effect of eK8 neutralization on invasion, its presence exclusively in cancer cells and the association of K8 expression with aggressive features and poor clinical outcome in HNSCC unravel eK8 as key player in invasion and a promising therapeutic target in HNSCC.

FOXD2-AS1 promotes migration and invasion of head and neck squamous cell carcinoma and predicts poor prognosis.

Aim: To investigate the role of long noncoding RNA FOXD2-AS1 in head and neck squamous cell carcinoma (HNSCC). Materials & methods: The expression and clinical significance of FOXD2-AS1 were analyzed using data from public databases. Transwell assays were used to examine the function of FOXD2-AS1 in HNSCC. The molecular mechanism of FOXD2-AS1 was probed by western blotting. Results: The expression of FOXD2-AS1 was upregulated in HNSCC; it was positively related with the pathological stage as well as with poor prognosis in HNSCC patients. FOXD2-AS1 silencing inhibited HNSCC cell migration and invasion, also influenced the expression of epithelial-mesenchymal transition-related molecules. Conclusion: FOXD2-AS1 was a prognostic marker in patients with HNSCC and may be a favorable novel treatment target for HNSCC.

Slug is a novel molecular target for head and neck squamous cell carcinoma stem-like cells.

The acquisition of stem-like phenotype is partly attributed to the induction of epithelial-mesenchymal transition (EMT). Thus, the activation of factors involved in EMT can be linked to cancer stem cell genesis. However, the underlying mechanisms in head and neck squamous cell carcinoma (HNSCC) remain largely unknown. Herein, we investigate whether slug, one of the major effectors of EMT, affects the stemness of HNSCC cells. We performed in vitro experiments to determine whether slug gene manipulation can influence the stemness phenotypes, including the capacity for self-renewal, expression of putative stemness markers, chemoresistance, and invasion in HNSCC cells. Further, we identified whether Slug knockout attenuates tumorigenicity of HNSCC cells in vivo. Finally, we examined whether prognosis of HNSCC patients after curative treatment may be affected by the level of slug expression. Overexpression of slug promoted self-renewal of HNSCC cells via activation of sphere formation, the expression of stem cell markers, and induction of chemoresistance to cisplatin. Also, slug overexpression increased the migration and invasion of HNSCC cells in vitro and was mainly observed during the invasion in HNSCC xenograft mouse model. By contrast, slug expression knockdown abrogated their self-renewal capacity, stemness-associated gene expression, and cisplatin chemoresistance. Furthermore, high levels of slug expression correlated with poor prognosis of patients with HNSCC. Inhibition of slug expression may represent a novel therapeutic strategy targeting HNSCC stem-like cells.

Arsenic trioxide disturbs the LIS1/NDEL1/dynein microtubule dynamic complex by disrupting the CLIP170 zinc finger in head and neck cancer

Cancer mortality is mainly caused by metastasis, which requires dynamic remodeling of cytoskeletal components such as microtubules. Targeting microtubules presents a promising antimetastatic strategy that could prevent cancer spreading and recurrence. It is known that arsenic trioxide (ATO) is able to inhibit the migration and invasion of solid malignant tumors, but its exact molecular mechanism remains unclear. Here, we report a novel molecular target and antimetastatic mechanism of ATO in head and neck squamous cell carcinoma (HNSCC). We found that cytoplasmic linker protein 170 (CLIP170) was overexpressed in HNSCC tissues and cells compared to normal controls. ATO at non-cytotoxic level (1 μM) inhibited the migration and invasion of HNSCC cells by displacing zinc in the zinc finger motif of CLIP170, which is a key protein that controls microtubule dynamics. The antimetastatic effects of ATO were equivalent to those of siRNA-mediated CLIP170 knockdown. Furthermore, ATO dysregulated microtubule polymerization via the CLIP170/LIS1/NDEL1/dynein signaling pathway in Cal27 cells as a functional consequence of CLIP170 zinc finger disruption. The effect was partially reversed by zinc supplementation. Taken together, these findings reveal that CLIP170 is a novel molecular target of ATO and demonstrate the capability and underlying mechanisms of ATO as a potential antimetastatic agent for HNSCC treatment.

UBE2O Promotes Progression and Epithelial-Mesenchymal Transition in Head and Neck Squamous Cell Carcinoma.

BackgroundUBE2O, as a member of the ubiquitin-conjugating enzyme family, is abnormally expressed and exhibits abnormal functions in human malignancies. However, the function of UBE2O in head and neck squamous cell carcinoma (HNSCC) remains unknown. Therefore, our study aims to investigate the role of UBE2O in HNSCC progression and the underlying mechanisms.MethodsThe expression of UBE2O in HNSCC patients was investigated with data from the Cancer Genome Atlas (TCGA) and from a separate primary tumor cohort. The function of UBE2O in HNSCC cells was studied by cell viability assay, colony formation assay, wound healing assay, and cell migration and invasion chamber assay. The effect of UBE2O on tumor growth in vivo was determined in a subcutaneous xenograft model of HNSCC.ResultsTCGA data showed that UBE2O mRNA expression was dramatically increased in HNSCC tissues and that patients with high expression of UBE2O transcripts had a worse survival prognosis than patients with low expression of UBE2O transcripts. Gain-of-function and loss-of-function analyses revealed that oncogenic UBE2O enhanced the proliferation, migration and invasion of HNSCC cells in vitro. Further, mechanistic analysis revealed that UBE2O induced the epithelial–mesenchymal transition (EMT) phenotype and also potentiated TGF-β1-induced EMT, and thus leading to an enhanced capacity of migration and invasion in HNSCC. Finally, xenograft models showed that UBE2O knockout obviously inhibited the occurrence of EMT, angiogenesis and tumor growth in HNSCC in vivo.ConclusionOur study indicates that UBE2O acts as an oncogene to promote the malignant progression and EMT of HNSCC.