Head And Neck Squamous Carcinoma Cells Research Articles

Comprehensive analysis of endoplasmic reticulum stress related signature in head and neck squamous carcinoma

Head and neck squamous carcinoma (HNSC) is a prevalent malignant disease, with the majority of patients being diagnosed at an advanced stage. Endoplasmic reticulum stress (ERS) is considered to be a process that promotes tumorigenesis and impacts the tumor microenvironment (TME) in various cancers. The study aims to investigate the predictive value of ERS in HNSC and explore the correlation between ERS-related genes and TME. A series of bioinformatics analyses were carried out based on mRNA and scRNA-seq data from the TCGA and GEO databases. We conducted RT-qPCR and western blot to validate the signature, and performed cell functional experiments to investigate the in vitro biological functions of the gene. We identified 63 ERS-related genes that were associated with outcome and stage in HNSC. A three-gene signature (ATF6, TRIB3, and UBXN6) was developed, which presents predictive value in the prognosis and immunotherapy response of HNSC patients. The high-risk group exhibited a worse prognosis but may benefit from immunotherapy. Furthermore, there was a significant correlation between the signature and immune infiltration. In the high-risk group, fibroblasts were more active in intercellular communication, and more T cells were observed at the end of the sequential phase. The genes in the ERS-related signature were overexpressed in HNSC cells, and the knockdown of TRIB3 significantly inhibited cell proliferation and migration. This study established a novel ERS-related signature that has potential implications for HNSC therapy and the understanding of TME.

IGF2BP2 promotes head and neck squamous carcinoma cell proliferation and growth via the miR-98-5p/PI3K/Akt signaling pathway.

As a N6-methyladenosine reader protein, Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) is a critical player in tumor progression and metastasis. However, its specific function in head and neck squamous carcinoma (HNSCC) has yet to be determined. The present study aimed to determine the role of IGF2BP2 in HNSCC. The expression of IGF2BP2 in HNSCC was analyzed using The Cancer Genome Atlas (TCGA) dataset and detected in HNSCC tissues and cells, respectively. Gain- and loss- of function methods were employed to study the effects of IGF2BP2 on HNSCC cell proliferation and tumorigenesis in vitro and in vivo. MicroRNAs (miRNAs) regulating IGF2BP2 were predicted using online tools and confirmed experimentally. We showed augmented IGF2BP2 expression in HNSCC, which correlated with poor clinical outcomes. Functional studies showed that IGF2BP2 promoted HNSCC cell proliferation by facilitating cell cycle progression while inhibiting apoptosis. We further demonstrated that IGF2BP2 could enhance HNSCC cell tumorigenesis in vivo. Mechanistically, our data revealed that miR-98-5p could directly target IGF2BP2. The interplay between IGF2BP2 and miR-98-5p is essential to drive the progression of HNSCC via the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)-protein kinase B (Akt) pathway signaling pathway. The current study revealed the oncogenic role of IGF2BP2 and provided insights into its potential mechanism in HNSCC tumorigenesis. Additionally, IGF2BP2 might represent a promising therapeutic target and serve as prognostic biomarker in patients with HNSCC.

Neddylation inhibitor MLN4924 sensitizes head and neck squamous carcinoma cells to (S)-10-hydroxycamptothecin

Head and neck squamous carcinoma (HNSCC) is the seventh most common cancer worldwide. Targeted therapeutic drugs for HNSCC are still being explored. Among them, (S)-10-hydroxycamptothecin (10-HCPT), a specific inhibitor of TOP1, functions by DNA double-strand breaks that can inhibit DNA replication and trigger apoptotic cell death subsequently. Previous studies have reported that MLN4924 exerts potent anti-tumor effects by inhibiting cullin–RING ligases and causing substrate accumulation in a variety of cancers. Here, we show that MLN4924 effectively causes dose-dependent accumulation of topoisomerase I (TOP1) and blocks TOP1 ubiquitination. Importantly, neddylation inhibition with MLN4924 acts synergistically with 10-HCPT to suppress cell growth, migration and apoptosis in HNSCC cells. Mechanistically, transcriptome sequencing shows that the cytotoxic effects of the combination of MLN4924 and 10-HCPT may involve activation of the NFKB1 pathway. Taken together, our results suggest that combined treatment with MLN4924 and 10-HCPT may be an effective strategy in HNSCC.

Effect of GNA13 on the alteration of tumor microenvironmental components through exosomes to promote the development of head and neck tumors.

e18035 Background: Guanine nucleotide-binding protein alpha subunit 13 (GNA13) is closely related to tumor development, but the effect of GNA13 on the biological behavior of head and neck tumors is unknown. The aim of this study was to investigate whether GNA13 can influence the alteration of tumor microenvironment components through exosomes, which in turn promotes the development of head and neck squamous carcinoma (HNSCC). Methods: Using the Gene Expression Omnibus database, the differentially expressed gene GNA13 was screened. Immunohistochemistry and western blotting were used to detect the expression of GNA13 in HNSCC tissues and control tissues. GNA13 expression was down-regulated in tumor cell lines using transfection techniques. The effect of GNA13 downregulation on tumor cell growth was examined by in vitro experiments. RT-PCR and dual luciferase reporter gene assays were used to validate GNA13-regulated miRNAs and their target genes. Clonogenesis assays were used to examine the effect of target gene expression on fibroblasts, and the HNSCC xenograft mouse model was used to verify the role of GNA13 in tumor growth in vivo. The peripheral blood from patients with different stages of HNSCC was collected to determine the expression level of GNA13 in serum exosomes and to analyze its relationship with metastasis and postoperative recurrence. Results: GNA13 expression was elevated in HNSCC tissues and cells. The growth capacity of HNSCC cells was significantly reduced after downregulation of GNA13, which induced fibroblast conversion to MAF via exosomes and promoted their proliferation and migration. Meanwhile, GNA13 was able to regulate miR-26a-5p/STRADB expression in fibroblasts via exosomes. The overexpression of STRADB promoted the proliferation and migration of fibroblasts and induced their conversion to MAF. More importantly, in the conditioned medium of STRADB overexpressing fibroblasts, the proliferation and migration of HNSCC cells were promoted. Furthermore, knockdown of GNA13 expression inhibited the tumor growth in nude mice. It appeared that high expression of GNA13 in serum exosomes of patients with HNSCC was associated with poor prognosis. Conclusions: GNA13 regulates the miR-26a-5p/STRADB axis in fibroblasts via exosomes to create a metastasis-friendly microenvironment for tumor cells, ultimately promoting the progression of HNSCC. Meanwhile, the expression of GNA13 was positively correlated with the pathological grade and clinical stage of HNSCC, which seems to be a reliable indicator of tumor recurrence. Targeting this signaling pathway would be a promising therapeutic strategy for HNSCC.

Polyphenol Extract from "Greco" Grape Canes: Characterization, Antioxidant Capacity, and Antitumor Effects on Cal-33 and JHU-SCC-011 Head and Neck Squamous Cell Carcinoma.

In the current study, we determined the antioxidant properties of “Greco” grape cane extracts, a typical cultivar of southern Italy. We also explored the anticancer activity of the polyphenol-rich fraction of the extract on head and neck squamous carcinoma cells (HNSCC) and investigated the underlying mechanism. Aqueous extracts were prepared at different pHs and extraction times and the total phenolic and reducing sugar contents were estimated. Radical Scavenging Activity (RSA), Ferric Reducing Antioxidant Power (FRAP), and Total Antioxidant Capacity (TAC) of the extracts were measured. A polyphenol-rich fraction, accounting for 6.7% by weight and characterized mainly by procyanidins and stilbenoids, was prepared from the extract obtained at pH 7 for 60 min. We demonstrated that the extract exerted a cytotoxic effect on HNSCC cell lines by inducing cell cycle arrest via cyclin downregulation and p21 upregulation, and by triggering apoptosis through caspase cascade activation, PARP-1 cleavage, and an increase in the Bax/Bcl-2 ratio. We furnished evidence that the polyphenol-rich fraction played the major role in the anticancer activity of the extract. These outcomes highlighted grape canes from the “Greco” cultivar as a valuable source of polyphenols that may represent good candidates for the design of innovative adjuvant therapies in the treatment of HNSCC.

Apis mellifera propolis enhances apoptosis and invasion inhibition in head and neck cancer cells.

BackgroundPropolis is a resinous product accumulated from several plant sources that possess a wide range of therapeutic properties, including anti-cancer activities. However, the role of honeybee-produced propolis on head and neck squamous carcinoma (HNSCC) is not well understood. The aim of this study was to investigate the effects of Apis mellifera propolis on apoptosis and invasiveness in HNSCC cell lines.MethodsEthyl acetate extract of propolis (EAEP) was prepared from A. mellifera beehives using liquid–liquid extraction. High-performance liquid chromatography coupled with electrospray ionization-time of flight-mass spectrometry (HPLC-ESI-TOF-MS) was used to determine the flavonoids in EAEP. Isogenic HNSCC cell lines derived from primary (HN30 and HN4) and metastatic site (HN31 and HN12) were used in this study. The cytotoxicity, apoptosis, invasion, and MMP activity of EAEP on HNSCC cells were determined using an MTT assay, flow cytometry, Matrigel invasion assay, and gelatinase zymography, respectively.ResultsWe found that EAEP exhibited cytotoxic activity and induced apoptosis in the HNSCC cell lines. Furthermore, EAEP significantly decreased HNSCC cell invasion by reducing MMP-2 and MMP-9 activity. Two flavonoids, galangin and apigenin, were identified in EAEP by HPLC-ESI-TOF-MS. The results suggest that EAEP promotes apoptosis and exerts anti-invasion potential by inhibiting MMP-2 and MMP-9 activity in HNSCC cell lines. These inhibitory effects may be mediated by galangin and apigenin.

Combination of ACY-241 and JQ1 Synergistically Suppresses Metastasis of HNSCC via Regulation of MMP-2 and MMP-9.

Overexpression of histone deacetylase 6 (HDAC6) and bromodomain-containing protein 4 (BRD4) is related to aggressiveness of head and neck squamous carcinoma (HNSCC). Based on studies that HDAC6 and BRD4 are potential therapeutic targets of HNSCC, we hypothesized that the combination treatment of BET inhibitor JQ1 and HDAC6-selective inhibitor ACY-241 could exhibit synergistic anticancer effects in human papillomavirus (HPV)-positive and HPV-negative HNSCC cells. In this study, HNSCC cell growth and viability were measured by CCK-8 assay, apoptosis was analyzed by flow cytometry, and metastasis was studied by wound healing and transwell assays. Furthermore, immunoblotting is conducted to investigate proteins that modulate apoptosis or metastasis. Here, we report that the combination of ACY-241 and JQ1 shows synergistic cell growth inhibition, viability reduction, and apoptosis induction in HNSCC cells through inactivation of AKT and NF-κB signaling. Importantly, we demonstrate that combined treatment of ACY-241 and JQ1 synergistically suppresses TNF-α-induced migration and invasion via dysregulating matrix metalloproteinase (MMP)-2, MMP-9, and MT1-MMP. Overall, the combination of ACY-241 and JQ1 significantly suppresses proliferation and metastasis in HPV-positive and HPV-negative HNSCC. Collectively, these findings suggest that the co-inhibition of BET and HDAC6 can be a new therapeutic strategy in HNSCC.

Antisense oligonucleotides targeting lncRNA AC104041.1 induces antitumor activity through Wnt2B/\u03b2-catenin pathway in head and neck squamous cell carcinomas

Long non-coding RNAs (lncRNAs) contribute to the initiation and progression of various tumors, including head and neck squamous carcinoma (HNSCC), which is a common malignancy with high morbidity and low survival rate. However, the mechanism of lncRNAs in HNSCC tumorigenesis remains largely unexplored. In this work, we identified a novel lncRNA AC104041.1 which is highly upregulated and correlated with poor survival in HNSCC patients. Moreover, AC104041.1 overexpression significantly promoted tumor growth and metastasis of HNSCC in vitro and in vivo. Mechanistically, AC104041.1 mainly located in the cytoplasm and could function as ceRNA (competing endogenous RNA) for miR-6817-3p, thereby stabilized Wnt2B, and consequently inducing β-catenin nuclear translocation and activation. Moreover, we demonstrate that salinomycin, which as a highly effective antibiotic in the elimination of cancer stem cells through the Wnt/β-catenin signaling, could enhance the inhibition of tumor growth by antisense oligonucleotides (ASO) targeting AC104041.1 in HNSCC cells and PDXs (patient-derived xenograft) model. Thus, our data provide preclinical evidence to support a novel strategy of ASOs targeting AC104041.1 in combination with salinomycin and may as a beneficial treatment approach for HNSCC.

Silencing of long non-coding RNA LINC00520 promotes radiosensitivity of head and neck squamous cell carcinoma cells

Aberrant expression of LINC00520 has been identified in head and neck squamous carcinoma (HNSCC). However, its function in the radiosensitivity of HNSCC remain unclear. Herein, we aimed to define the role LINC00520 in the radiosensitivity of HNSCC and identify the underlying mechanism. Tumour tissues and adjacent normal tissue were collected from HNSCC patients. Differentially expressed genes (DEGs) in HNSCC tumour were obtained from the cancer genome atlas (TCGA) database. Interactions between LINC00520 and miR-195, homeobox A10 (HOXA10) and miR-195 were evaluated by dual-luciferase reporter gene assay, RNA Immunoprecipitation (RIP), and RNA pull-down assay. The effects of LINC00520/miR-195/HOXA10 on radiosensitivity of HNSCC were analysed in the evaluation of radiotherapy outcome. Cell proliferation, invasion, migration, and apoptosis of HNSCC cells were accessed via gain- and loss-of-function approaches. Tumour xenograft in nude mice was conducted in order to confirm the results in vivo. LINC00520 was upregulated while miR-195 was downregulated in HNSCC cells and tissues. Silencing LINC00520 or overexpressing miR-195 promoted radiosensitivity and inhibited cell proliferation, invasion, migration, and apoptosis in HNSCC. Moreover, these in vitro findings were reproduced in vivo in human HNSCC xenograft in nude mice. LINC00520/miR-195/HOXA10 is involved in the radiosensitivity mediation, providing potential therapeutic target for HNSCC treatment.

Seramid Metabolizmasının HNSCC Hücrelerinde Primer Silia Uzunluğu ve Tümör Metastazına Etkisi

In the last decade, particular sphingolipids have become renowned for their participation in cell membrane functions and signaling proceedings that regulate a wide array of cellular manners. Ceramide is a major molecule of sphingolipids metabolism. It plays vital roles in mediating the major cellular functions such as cell differentiation, cell-to-cell communication, apoptosis, and proliferation. Recent studies have shown that ceramide metabolism and their metabolic enzymes take important role during migration and cell mobility process. However, the molecular mechanism of sphingolipids involved is unknown. Our efforts in this study, which are serving mechanistically the understanding of ceramide, will be shade some light on this unknown. In this work, particularly, we looked at the effect of ceramide syntheses on migration ability of UM-SCC-22A head and neck squamous carcinoma cells. Briefly, we identified that alterations in ceramide metabolism by pharmacological inhibitor fumonisin B1, reducing bioactive ceramides, results in activation of the TGF-ß receptor type I and II (TßRI/II) cell surface localization and, leading to increased cell migration/invasion in UM-SCC-22A head and neck squamous carcinoma cells. On the other hand, primary cilia length in UM-SCC-22A cells did not changed by decreased ceramide amount. Thus, these data reveal that ceramide synthases/ceramide is a novel factor that regulates TßRI/II to the primary cilium, controlling cell migration and cancer metastasis.

Genomic and Transcriptomic Alterations Associated with STAT3 Activation in Head and Neck Cancer.

BackgroundHyperactivation of STAT3 via constitutive phosphorylation of tyrosine 705 (Y705) is common in most human cancers, including head and neck squamous carcinoma (HNSCC). STAT3 is rarely mutated in cancer and the (epi)genetic alterations that lead to STAT3 activation are incompletely understood. Here we used an unbiased approach to identify genomic and epigenomic changes associated with pSTAT3(Y705) expression using data generated by The Cancer Genome Atlas (TCGA).Methods and FindingsMutation, mRNA expression, promoter methylation, and copy number alteration data were extracted from TCGA and examined in the context of pSTAT3(Y705) protein expression. mRNA expression levels of 1279 genes were found to be associated with pSTAT3(705) expression. Association of pSTAT3(Y705) expression with caspase-8 mRNA expression was validated by immunoblot analysis in HNSCC cells. Mutation, promoter hypermethylation, and copy number alteration of any gene were not significantly associated with increased pSTAT3(Y705) protein expression.ConclusionsThese cumulative results suggest that unbiased approaches may be useful in identifying the molecular underpinnings of oncogenic signaling, including STAT3 activation, in HNSCC. Larger datasets will likely be necessary to elucidate signaling consequences of infrequent alterations.

Abstract 3359: Expression of stem cell markers Oct3/4 and Nanog in the head and neck squamous carcinoma cells and its clinical implications for delayed neck metastasis in stage I/II tongue squamous cell carcinoma

Abstract Background: The side population (SP) of cancer cells is reportedly enriched with cancer stem cells (CSCs), however, the functional role and clinical relevance of CSC marker molecules upregulated in the SP of head and neck squamous carcinoma (HNSCC) cells are yet to be elucidated. Patients with clinical stage I/II (T1-2N0M0) tongue squamous cell carcinoma (TSCC) typically undergo partial glossectomy alone; however, development of delayed neck metastasis (DNM) tends to reduce their survival. In the present study, we aimed to determine the CSC markers in the SP of HNSCC cells along with their functions in cellular behaviors, and to clarify the association of these markers with DNM. Methods: Flow cytometry was applied to isolate SP from main population (MP) in HNSCC cells (SCC4, SAS, and HSC4). The expression of the CSC markers was examined by semi-quantitative RT-PCR and immunocytochemistry. In vitro proliferation, migration, and invasion assays were performed to assess cellular behaviors. Clinicopathological factors and immunohistochemical expressions of Oct3/4 and Nanog were evaluated using surgical specimens from 50 patients with stage I/II TSCC who underwent partial glossectomy alone. Results: SPs were isolated in all three cell lines examined. Expression levels of Oct3/4 and Nanog were higher in SP cells than MP cells. Additionally, cell migration and invasion abilities were higher in SP cells than MP cells, whereas there was no difference in proliferation. Univariate analysis showed that expression of Oct3/4 and Nanog, vascular invasion, muscular invasion, and mode of invasion were significantly correlated with DNM. Multivariate logistic regression revealed that Oct3/4 expression (risk ratio = 14.78, p = 0.002) and vascular invasion (risk ratio = 12.93, p = 0.017) were independently predictive of DNM. Regarding the diagnostic performance, Oct3/4 showed the highest accuracy, sensitivity, and negative predictive value of 82.0%, 61.5%, and 86.8%, respectively, while vascular invasion showed the highest specificity and positive predictive value of 94.6% and 71.4%, respectively. Conclusion: These results suggest that Oct3/4 and Nanog represent probable CSC markers in HNSCC, which contribute to the development of DNM in part by enhancing cell motility and invasiveness. Moreover, along with vascular invasion, expression of Oct3/4 in the primary cancer cells can be considered a potential predictor for selecting patients at high risk of developing DNM. Citation Format: Noboru Habu, Yorihisa Imanishi, Kaori Kameyama, Masayuki Shimoda, Yutaka Tokumaru, Koji Sakamoto, Ryoichi Fujii, Seiji Shigetomi, Kuninori Otsuka, Yoichiro Sato, Yoshihiro Watanabe, Hiroyuki Ozawa, Toshiki Tomita, Masato Fujii, Kaoru Ogawa. Expression of stem cell markers Oct3/4 and Nanog in the head and neck squamous carcinoma cells and its clinical implications for delayed neck metastasis in stage I/II tongue squamous cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3359.

Abstract A121: Constitutive K-Ras activity independent of K-RAS mutational status leads to resistance to anti-EGFR molecular targeting approaches and MEK-dependent reactivation of Akt following PI3K inhibition

Abstract Non-small cell lung cancer (NSCLC) cells expressing K-RAS mutation are resistant to anti-EGFR antibody cetuximab. Oncogenic Ras regulates basal effector PI3K/Akt and MAPK/ERK pathways. In this study, we investigated impact of K-RAS activity independent of its mutational status on targetibility of EGFR as well as the PI3K/Akt and MAPK/ERK pathways. A panel of five NSCLC cells (A549, H460, H661, SK-MES-1, HTB-182) and five head and neck squamous carcinoma (HNSCC) cells (SAS, FaDu, UT-SCC-5, UT-SCC-15, UT-SCC-5R (UT-SCC-5R are UT5 cells acquired resistance to cetuximab) were studied. K-Ras was constitutively activate not only in K-RAS mutated (K-RASmut) A549 and H460 cells, but also in K-RAS wild-type (K-RASwt) SAS and UT-SCC-5R cells. Enhanced K-Ras-GTP either endogenously or following overexpression of K-RAS(V12) was associated with significant shortening of population doubling time and increased clonogenic activity of tu-mor cells from both origin. Constitutive activation of K-Ras independent of K-RAS muta-tional status led to desensitization of both K-RASmut and K-RASwt cells to anti-EGFR an-tibody cetuximab and EGFR-tyrosine kinase inhibitors (TKI) erlotinib and AG1478, tested by standard clonogenic assay. Analyzing EGFR downstream pathways revealed that lack of response to the EGFR-TK inhibitors is through activation of the PI3K/Akt pathway. Thus, inhibition of PI3K was supposed to be an efficient approach to block clonogenic activity. However, PI3K inhibitor completely blocked clonogenic activity only in cells expressing low level of K-RASwt from both origins. In K-RASmut NSCLC cells or in HNSCC cells with overexpression of K-RASwt a partial response to PI-103 was observed. Analyzing pathway activity revealed that PI-103 does not inhibit Akt activity after 24 h pre-treatment while up to 4 h after post-treatment with PI-103, phosphorylation of Akt and Akt substrates (PRAS40 and GSK3αβ) are completely blocked. Lack of effect of PI103 at 24 h post-treatment was shown to be through K-RAS/MEK/ERK dependent reactivation of Akt. In line with this observation, targeting MEK by PD98059 significantly improved the anti-clonogenic activity of PI-103. Although, PD98059 blocked phosphorylation of ERK1/2, no marked effect was observed on clonogenic activity. Thus, EGFR or PI3K, but not MEK are appropriate target to inhibit clonogenic activity of tumor cells expressing low level of K-RASwt. In tumor cells with constitutive K-RAS activity, dual targeting of PI3K and MEK is an efficient approach to inhibit clonogenicity. Supported by grants from the Deutsche Forschungsgemeinschaft [Ro527/7-1 and SFB-773-TP B02] awarded to HPR, GRK 1302/2 (T11) awarded to MT/HPR. Citation Format: Mahmoud Toulany, Mohammad Saki, H. Peter Rodemann. Constitutive K-Ras activity independent of K-RAS mutational status leads to resistance to anti-EGFR molecular targeting approaches and MEK-dependent reactivation of Akt following PI3K inhibition. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A121.

Expression of Oct3/4 and Nanog in the head and neck squamous carcinoma cells and its clinical implications for delayed neck metastasis in stage I/II oral tongue squamous cell carcinoma.

BackgroundThe side population (SP) of cancer cells is reportedly enriched with cancer stem cells (CSCs), however, the functional role and clinical relevance of CSC marker molecules upregulated in the SP of head and neck squamous carcinoma (HNSCC) cells are yet to be elucidated. Patients with clinical stage I/II (T1-2N0M0) tongue squamous cell carcinoma (TSCC) typically undergo partial glossectomy; however, development of delayed neck metastasis (DNM) tends to reduce their survival. In the present study, we aimed to determine the CSC markers in the SP of HNSCC cells along with their functions in cellular behaviors, and to clarify the association of these markers with DNM.MethodsFlow cytometry was applied to isolate SP from main population (MP) in HNSCC cells. The expression of the CSC markers was examined by semi-quantitative RT-PCR and immunocytochemistry. In vitro proliferation, migration, and invasion assays were performed to assess cellular behaviors. Clinicopathological factors and immunohistochemical expressions of Oct3/4 and Nanog were evaluated using surgical specimens from 50 patients with stage I/II TSCC.ResultsSPs were isolated in all three cell lines examined. Expression levels of Oct3/4 and Nanog were higher in SP cells than MP cells. Additionally, cell migration and invasion abilities were higher in SP cells than MP cells, whereas there was no difference in proliferation. Univariate analysis showed that expression of Oct3/4 and Nanog, vascular and muscular invasion, and mode of invasion were significantly correlated with DNM. Multivariate logistic regression revealed that Oct3/4 expression (risk ratio = 14.78, p = 0.002) and vascular invasion (risk ratio = 12.93, p = 0.017) were independently predictive of DNM. Regarding the diagnostic performance, Oct3/4 showed the highest accuracy, sensitivity, and NPV of 82.0 %, 61.5 %, and 86.8 %, respectively, while vascular invasion showed the highest specificity and PPV of 94.6 % and 71.4 %, respectively.ConclusionThese results suggest that Oct3/4 and Nanog represent probable CSC markers in HNSCC, which contribute to the development of DNM in part by enhancing cell motility and invasiveness. Moreover, along with vascular invasion, expression of Oct3/4 can be considered a potential predictor for selecting patients at high risk of developing DNM.

Activation of Ca 2+ ‐activated K + channel (SK4) Rescues Squamous Cancer Cells from Iononmycin‐induced Cell Death

The ion channels in cancer cells are drawing attention regarding cell proliferation and migration. Intracellular Ca2+ ([Ca2+]i)-dependent signaling has crucial influence to the fate of cancer. Here we investigate the role of Ca2+-activated K+ channels in head and neck squamous carcinoma cells (HNSCC); SNU-1076, OSC-19 and HN5. Treatment with 1 μM ionomycin (24-48 h) induced cell death in all the three cell lines. Whole- cell patch clamp study revealed the functional expression of Ca2+-activated Cl- chan- nels (CaCC, Ano-1) and Ca2+-activated nonselective cation channels (CAN). Ca2+- activated K+ channel (SK4) activity was variable between cell lines; at a raised[Ca2+]i (0.6 μM) or with 1 μM ionomycin, only SNU-1076 showed prominent SK4 current (ISK4). However, an application of SK4 activator (1-EBIO) induced robust ISK4 with membrane hyperpolarization in OSC-19 as well as SNU-1076 while not in in HN5 cells. The EBIO-induced ISK4 was completely suppressed by TRAM-34, a selec-tive SK4 blocker. Interestingly, the ionomycin-induced cell death was effectively prevented by 1 - 30 μM 1-EBIO in SNU-1076 and OSC-19. Consistently, the rescue effect was annihilated by combined treatment with TRAM-34. The rescue by 1-EBIO was not effective in HN5. Above results newly demonstrate the role of SK4 and membrane hyperpolarization in HNSCCs' proliferation and death. Pharmacological modulation of SK4 might provide an intriguing novel tool for the anti-cancer strategy in HNSCC.

Abstract 1017: Id-1 gene and protein as therapeutic target for head and neck squamous cell carcinoma

Abstract Squamous cell carcinoma is one of the most common malignancies in head and neck region. Primary tumors, especially derived from undifferentiated cells, tend to have aggressive phenotypes, which are mainly characterized by local recurrence and distant metastasis. In this study we found that Id-1, a negative regulator of tissue specific transcription factors, is highly expressed in head and neck squamous carcinoma cells (HNSCC), and that the expression is correlated with the malignant phenotype, i.e., cell proliferation and invasion. Id-1 knockdown dramatically reduces squamous cell invasion that is accompanied by profound morphologic changes and robust reduction in expression levels of mesenchymal markers.In addition, reduction in tumor growth and neoangiogenesis were observed in vivo, indicating that knock-down of Id-1 drastically suppresses VEGFA expression. Our results also suggested that VEGFA-autocrine loop activates tylosine kinase pathways including Srk and FAK, and therefore manifests invasive phenotype. With clinical materials obtained from HNSCC patients, significant correlation was observed between Id-1 and VEGFA. Furthermore, we demonstrated that a non toxic compound, cannabidiol, significantly downregulates Id-1 gene expression and associated squamous cell proliferation and invasiveness. Taken together, these results suggest that Id-1 controls cancer cell phenotype in culture and in vivo, and that drugs targeting Id-1 represent a novel and promising strategy for improving the therapy and outcome of patients with HNSCC. Citation Format: Ryuichi Murase, Sean McAllister, Yohei Fujita, Tomoki Sumida, Koichi Nakashiro, Pierre Desprez, Hiroyuki Hamakawa. Id-1 gene and protein as therapeutic target for head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1017. doi:10.1158/1538-7445.AM2014-1017

Oct4 is a critical regulator of stemness in head and neck squamous carcinoma cells

Cancer stem cells (CSCs) have been suggested as responsible for the initiation and progression of cancers. Octamer-binding transcription factor 4 (Oct4) is an important regulator of embryonic stem cell fate. Here, we investigated whether Oct4 regulates stemness of head and neck squamous carcinoma (HNSC) CSCs. Our study showed that ectopic expression of Oct4 promotes tumor growth through cyclin E activation, increases chemoresistance through ABCC6 expression and enhances tumor invasion through slug expression. Also, Oct4 dedifferentiates differentiated HNSC cells to CSC-like cells. Furthermore, Oct4(high) HNSC CSCs have more stem cell-like traits compared with Oct4(low) cells, such as self-renewal, stem cell markers' expression, chemoresistance, invasion capacity and xenograft tumorigeneity in vitro and in vivo. In addition, knockdown of Oct4 led to markedly lower HNSC CSC stemness. Finally, there was a significant correlation between Oct4 expression and survival of 119 HNSC patients. Collectively, these data suggest that Oct4 may be a critical regulator of HNSC CSCs and its targeting may be potentially valuable in the treatment of HNSC CSCs.

Transcriptional factor ID-1 facilitates invasion and neoangiogenesis in head and neck squamous cell carcinoma

Squamous cell carcinoma is one of the most common malignancies in head and neck region. Primary tumors, especially derived from undifferentiated cells, tend to have an aggressive phenotype, mainly characterized by local recurrence and distant metastasis. In this study we found that Id-1, a negative regulator of tissue specific transcription factors, is highly expressed in head and neck squamous carcinoma cells (HNSCC), and that the expression correlated with the malignant phenotype, i.e., cell proliferation and invasion.

Abstract B35: Alternate receptor tyrosine kinases provide protection from FGFR inhibition in HNSCC cells as identified by genome-wide shRNA screening

Abstract The efficacy of many biologically targeted cancer therapies is limited by intrinsic and acquired resistance. Head and neck squamous carcinoma (HNSCC) patients show only a 4–10% response to the epidermal growth factor receptor (EGFR) inhibitors, gefitinib and erlotinib, despite EGFR over-expression in over 90% of tumors. Our lab has previously shown that gefitinib insensitive non-small cell lung cancer (NSCLC) cell lines exhibit dominant autocrine fibroblast growth factor receptor (FGFR) signaling. RNAi-based loss-of-function screens are an important tool to identify synthetic lethal interactions between the inhibition of two genes in order to efficiently identify functional survival mechanisms and potent drug combinations. We deployed a whole genome screen to identify genes whose knockdown potentiated the inhibitory effect of the FGFR inhibitor, AZ12908010, in HNSCC cell lines. We found that multiple alternate receptors provided protection from FGFR inhibition in these cell lines, including the receptor tyrosine kinases (RTKs) epidermal growth factor receptor 2 (ErbB2) and hepatocyte growth factor receptor (Met). We validated the results of the screen by showing that specific knockdown of either ErbB2 or Met in combination with FGFR inhibitor treatment led to increased inhibition of growth relative to FGFR tyrosine kinase inhibitor (TKI) treatment alone. These results were confirmed using specific small molecule inhibitors of either ErbB2 or Met. The combination therapies did not lead to greater inhibition of growth in the cell lines where ErbB2 and Met were not identified as synthetic lethal with FGFR. We extended the study to find that the combination of knockdown of either ErbB2 or Met with FGFR inhibition decreased the growth of additional cell lines, indicating that the combination therapies could be broadly applicable. These results reveal a role for alternate RTKs in maintaining pro-growth and survival signaling in HNSCC cells in the setting of FGFR inhibition. Thus, improved therapies for HNSCC patients could involve rationally designed combinations of TKIs targeting FGFR and either ErbB family members or Met.

Activation of the Insulin-like Growth Factor-1 Receptor Induces Resistance to Epidermal Growth Factor Receptor Antagonism in Head and Neck Squamous Carcinoma Cells

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have poor efficacy in head and neck squamous carcinoma cells (HNSCC). Because the IGF-1 receptor (IGF1R) generates potent prosurvival signals and has been implicated in therapeutic resistance, its ability to induce resistance to EGFR-TKIs was studied in vitro. Five HNSCC cell lines showed reduced sensitivity to the EGFR-TKI gefitinib when the IGF1R was activated. In SCC-25 and Cal27 cells, gefitinib inhibited basal and EGF-stimulated EGFR, extracellular signal-regulated kinase (Erk), and Akt phosphorylation and reduced cell number. This correlated with initiation of apoptosis based on a 4-fold increase in PARP cleavage and a 2.5-fold increase in Annexin V positivity. The apoptotic response and reduction in cell number were blocked by IGF1R activation, which resulted in phosphorylation of both Erk and Akt. In both the cell lines, IGF1R-induced Erk, but not Akt, activation was eliminated by gefitinib. IGF1R-induced gefitinib resistance was unaffected by MAP/Erk kinase inhibition with U0126 but was partially impaired by inhibition of phosphoinositide-3-kinase with LY294002. The IGF1R-TKI PQ401 inhibited growth of SCC-25 and Cal27 cells alone and also acted synergistically with gefitinib. Thus, the IGF1R can make HNSCC cells resistant to EGFR-TKI treatment via a prosurvival mechanism. Of the 8 HNSCC tumor samples studied, all samples expressed the IGF1R and 5 showed detectable IGF1R phosphorylation, suggesting that this receptor may be relevant in vivo, and thus, combined EGFR/IGF1R inhibition may be necessary in some patients for effective targeted molecular therapy.