Squamous Cell Carcinoma Of The Head And Neck Cell Lines Research Articles

Abstract 4936: Activity of carfilzomib in head and neck cancer cell lines in vitro

Abstract Background: Carfilzomib (CF) is a 2nd generation proteasome inhibitor with activity in hematologic cancer, but its study in solid tumors like squamous cell carcinoma of the head and neck (SCCHN) is limited. We investigated its antitumor activity in three SCCHN cell lines. Methods: Cells: We studied two human tongue cell lines (CAL27; SCC-25) and one pharynx line (FaDu); all HPV-negative and p53-mutant. MTT assays: We utilized MTT assays to evaluate cytotoxicity of CF, cisplatin, and their combination. The IC50 of CF and Combination Index (CI) of varying concentrations of combined CF and cisplatin were calculated. Clonogenic assays: Cells were seeded at low density and after 24 hours, cells were treated with varying concentrations of CF. Plates were incubated for 10 days. The cells were fixed and stained with crystal violet dye and colonies counted. Wound Healing assays: After cells reached 100% confluence, a scratch was created using a 200 µL micropipette. Cells were treated with CF and images were acquired at 0, 24, 48, and 72 hours post-scratch. Results: MTT assays: IC50 values as a function of exposure lengths are shown in Table 1. CAL27 was the most sensitive while SCC-25 was the most resistant. In all cell lines, the results of combined CF and cisplatin were complex: at lower doses there was evidence of antagonism, while at higher doses there was synergy. Clonogenic assays: CF significantly inhibited clonogenicity compared to DMSO control (P≤ 0.05). The surviving fraction for CF 2.5, 5, and 10 nM were 0.411. 0.151, 0.051, and 0.5, 0.339, 0.102 in CAL27 and SCC-25 cell lines, respectively. Wound Healing assays: Wound closure % after treatment with CF5 was significantly different from DMSO control (P≤0.05). Wound closure % for CF5 were 30.97, 56.75, and 28.03% compared to 94.65, 75.88, and 42.05% for control in CAL27, FaDu, and SCC-25 cell lines, respectively. Conclusion: CF exhibits antitumor effects in SCCHN in vitro. Our findings support further investigation of CF in combination with conventional agents in vitro and in vivo. IC50 values for carfilzomib in head and neck cancer cell lines Cell line 24 hours 48 hours 72 hours CAL27 18.02 (11.76- 28.22) 9.364 (7.189- 12.45) 6.401 (5.579- 7.373) FaDu 57.34 (41.98-84.90) 16.22 (13.438- 19.446) 8.237 (7.260- 9.365) SCC25 77.78 (67.18- 91.30) 12.87 (11.36- 14.64) 11.49 (10.51- 12.58) Citation Format: Abdullah S. Eldaly, Douglas B. Stairs, Mitchell Machtay. Activity of carfilzomib in head and neck cancer cell lines in vitro. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4936.

Silmitasertib, a casein kinase 2 inhibitor, induces massive lipid droplet accumulation and nonapoptotic cell death in head and neck cancer cells.

Accumulating evidence shows that high expression of casein kinase 2 (CK2) and phosphorylated acetyl CoA carboxylase (pACC) in patients with squamous cell carcinoma of the head and neck (SCCHN) correlates with decreased survival rates. Computational analysis has shown that ACC is a potential substrate for CK2, and its inhibition can suppress ACC phosphorylation in vitro. CX-4945, also known as silmitasertib, is an orally administered, highly specific, ATP-competitive inhibitor of CK2 and is under clinical investigation as a treatment for malignancies. We hypothesize that inhibition of CK2 by CX-4945 can reduce CK2-downstream phosphorylation of ACC as a therapeutic strategy against SCCHN. Three aggressive SCCHN cell lines (OSC-19, FaDu and HN31) were cultured to investigate the anticancer mechanism of the CK2 inhibitor, CX-4945. Cell cycle analysis, Annexin V/PI staining, and cleavage of PARP were performed to detect apoptosis. Western blot, electron microscopy and analysis of acidic vesicular organelle development were used to detect autophagy. Interference with cellular metabolism by CX-4945 treatment was determined by Seahorse XF24 Extracellular Flux Analyzer and mass spectrometry. Cellular metabolism was impeded by CX-4945 in aggressive SCCHN cells by Seahorse XF24 Extracellular Flux Analyzer and mass spectrometry, and consequently time- and dose-dependent lipid droplet accumulation and non-apoptotic cell death were observed. The lipogenic enzyme ACC was demonstrated to be associated with CK2, and its repressive phosphorylation could be removed by the CK2 inhibitor CX-4945. Overexpression of ACC resulted in impaired cell survival following transient transfection. The findings demonstrate that CK2 inhibition impairs normal cellular energy metabolism and may be an attractive therapy for treating aggressive SCCHN.

Metabolic Plasticity and Combinatorial Radiosensitisation Strategies in Human Papillomavirus-Positive Squamous Cell Carcinoma of the Head and Neck Cell Lines.

Simple SummaryA subset of head and neck cancers (SCCHN) are caused by human papillomavirus (HPV). As these tumours tend to affect younger patients and are associated with favourable survival, there is a pressing need to find ways to reduce long-term treatment toxicity while maintaining oncological efficacy. We studied utilisation of metabolic pathways in HPV-positive SCCHN cells with the aim of exploiting such for potential therapeutic benefit. We found that these tumours maintained metabolic diversity, in contrast to what we have observed in traditional SCCHN cells associated with mutations in the TP53 gene. This, in turn, correlated with susceptibility to metabolic inhibitors, insofar as a combination of these agents acting on different metabolic pathways was required to augment the effects of ionising radiation (a mainstay of treatment for SCCHN). Notionally, this may provide a means of treatment de-intensification by facilitating radiation dose reduction to minimise the impact of treatment on long-term function.Background: A major objective in the management of human papillomavirus (HPV)-positive squamous cell carcinoma of the head and neck (SCCHN) is to reduce long-term functional ramifications while maintaining oncological outcomes. This study examined the metabolic profile of HPV-positive SCCHN and the potential role of anti-metabolic therapeutics to achieve radiosensitisation as a potential means to de-escalate radiation therapy. Methods: Three established HPV-positive SCCHN cell lines were studied (UM-SCC-104, UPCI:SCC154, and VU-SCC-147), together with a typical TP53 mutant HPV-negative SCCHN cell line (UM-SCC-81B) for comparison. Metabolic profiling was performed using extracellular flux analysis during specifically designed mitochondrial and glycolytic stress tests. Sensitivity to ionising radiation (IR) was evaluated using clonogenic assays following no treatment, or treatment with: 25 mM 2-deoxy-D-glucose (glycolytic inhibitor) alone; 20 mM metformin (electron transport chain inhibitor) alone; or 25 mM 2-deoxy-D-glucose and 20 mM metformin combined. Expression levels of p53 and reporters of p53 function (MDM2, p53, Phospho-p53 [Ser15], TIGAR and p21 [CDKN1A]) were examined by western blotting. Results: HPV-positive SCCHN cell lines exhibited a diverse metabolic phenotype, displaying robust mitochondrial and glycolytic reserve capacities. This metabolic profile, in turn, correlated with IR response following administration of anti-metabolic agents, in that both 2-deoxy-D-glucose and metformin were required to significantly potentiate the effects of IR in these cell lines. Conclusions: In contrast to our recently published data on HPV-negative SCCHN cells, which display relative glycolytic dependence, HPV-positive SCCHN cells can only be sensitised to IR using a complex anti-metabolic approach targeting both mitochondrial respiration and glycolysis, reflecting their metabolically diverse phenotype. Notionally, this may provide an attractive platform for treatment de-intensification in the clinical setting by facilitating IR dose reduction to minimise the impact of treatment on long-term function.

Abstract LB018: Cloud-based biological domain knowledge derived gene expression classifier to predict the cancer clinical outcome

Abstract We report the advances of a cloud-based software utilizing advanced algorithms to identify the molecular cancer drivers and its signal transduction. To test, a classifier based on the NFκB signaling pathway gene expression profiles that predicts the clinical therapeutic response to chemo-radiation therapy of Squamous Cell Carcinomas of the Head and Neck (SCCHN) patients are described here. Expression of HPV16, p16 and 84 NFκB signaling pathway genes were determined using real time RT PCR in SCCHN patient samples and SCCHN cell lines. Gene expression was correlated to chemo-radiation response in cell lines and the model was blindly tested in SCCHN patients to predict their clinical outcome to chemo-radiation. This tool intends to fuse biological domain knowledge by way of integrating disease targets, cell line experiments towards creating a gene expression classifier for clinical outcome. The gene expression-based predicted clinical outcome compared with patients actual observed clinical outcome correctly identified the clinical response in 73% of the cases. Such work will allow design of tailored individualized clinical treatment strategies to target NFκB inhibition using biological modifying agents with or without chemo/radiation therapy. This will help to develop several targets to directly inhibit the NFκB activity or inhibit the downstream pivotal targets. The significance of the classifier would be the ability to use the biologic attributes of a tumor to tailor specific treatment protocols for each individual patient. This would not only spare the chemo-radiation resistant patients the ill effects of the therapy but will also decrease the delay in effective treatment among the resistant patients. The long-term objective is to use such pro-survival driver genes in other cancers; SMAD, TGFβ in pancreatic cancer, and AR in prostate cancer. This tool (MeghaOncomine) intends to fuse biological domain knowledge by way of integrating cancer targets, cell line experiments towards creating a gene expression classifier for clinical outcome. Citation Format: Rao V. Papineni, Seema Gupta, Aravindan Natarajan, Ram Papineni, Chandra Kasinathan. Cloud-based biological domain knowledge derived gene expression classifier to predict the cancer clinical outcome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB018.

Preclinical Evaluation of the Association of the Cyclin-Dependent Kinase 4/6 Inhibitor, Ribociclib, and Cetuximab in Squamous Cell Carcinoma of the Head and Neck.

Simple SummaryWe previously showed that ribociclib induces cell cycle arrest in some human papillomavirus (HPV)-negative squamous cell carcinomas of the head and neck (SCCHN) models. However, in vivo, ribociclib has only a cytostatic effect, suggesting that its activity needs to be optimized in combination with other treatments. We investigated the activity of ribociclib in combination with cetuximab in several HPV-negative SCCHN patient-derived tumor xenograft (PDTX) models. We found that the combination of cetuximab and ribociclib was not significantly more active than cetuximab monotherapy. In addition, our observations also suggest that the combination of cetuximab with a cyclin-dependent kinase (CDK) 4/6 inhibitor may reduce the activity of the CDK4/6 inhibitor in some cetuximab-resistant models. Our work has significant clinical implications since combinations of anti-epidermal growth factor receptor (EGFR) therapy and CDK4/6 inhibitors are currently being investigated in clinical trials.Epidermal growth factor receptor (EGFR) overexpression is observed in 90% of human papillomavirus (HPV)-negative squamous cell carcinomas of the head and neck (SCCHN). Cell cycle pathway impairments resulting in cyclin-dependent kinase (CDK) 4 and 6 activation, are frequently observed in SCCHN. We investigated the efficacy of ribociclib, a CDK4/6 inhibitor, in combination with cetuximab, a monoclonal antibody targeting the EGFR, in HPV-negative SCCHN patient-derived tumor xenograft (PDTX) models. The combination of cetuximab and ribociclib was not significantly more active than cetuximab monotherapy in all models investigated. In addition, the combination of cetuximab and ribociclib was less active than ribociclib monotherapy in the cetuximab-resistant PDTX models. In these models, a significant downregulation of the retinoblastoma (Rb) protein was observed in cetuximab-treated mice. We also observed Rb downregulation in the SCCHN cell lines chronically exposed and resistant to cetuximab. In addition, Rb downregulation induced interleukin 6 (Il-6) secretion and the Janus kinase family member/signal transducer and activator of transcription (JAK/STAT) pathway activation that might be implicated in the cetuximab resistance of these cell lines. To conclude, cetuximab is not an appropriate partner for ribociclib in cetuximab-resistant SCCHN models. Our work has significant clinical implications since the combination of anti-EGFR therapy with CDK4/6 inhibitors is currently being investigated in clinical trials.

Abstract PO-033: Metabolic differences between human papillomavirus-related and smoking-related squamous cell carcinoma of the head and neck independently predict overall patient survival

Abstract Background: Human papillomavirus (HPV) status and tobacco use are the strongest prognostic factors of survival for squamous cell carcinoma of the head and neck (SCCHN). Patients with HPV-related SCCHN live more than twice as long as patients with tobacco-related SCCHN. The underlying metabolic dysregulation characterizing these two clinically distinct groups may pose exciting translational targets that are yet unknown. Using a metabolome-wide approach, we investigated the metabolic differences of HPV vs smoking-related SCCHN in a large patient population. We then linked those metabolic differences to patient survival. Methods: We recruited 137 patients from Emory University hospitals and clinics: 55 HPV-positive never smokers (i.e., HPV-related SCCHN) and 82 HPV-negative current or former smokers (i.e., smoking-related SCCHN). We performed untargeted high-resolution metabolomics using liquid chromatography-mass spectrometry on pre-treatment patient plasma at the Emory Clinical Biomarkers Laboratory. Our statistical approach has three steps. 1) Metabolite feature selection: We aggregated the results from two selection algorithms (5-fold cross-validated partial least squares discriminant analysis and support vector machine) to determine the metabolites that differentiated HPV vs smoking-related SCCHN. 2) Metabolic pathway analysis (Mummichog): We identified statistically significant (P<0.05) metabolic pathways stemming from the step 1 metabolites. 3) Metabolic profile and survival analysis: We created a metabolite-based linear principal component using the significant pathway metabolites in step 2 and estimated its association with overall survival using adjusted Cox models. Results: Of the 9,640 extracted metabolites, the two models found 229 that differentiated HPV vs smoking-related SCCHN. Metabolic pathway analysis found fatty acid and steroid metabolism was significantly upregulated in HPV patients: bile acid biosynthesis (P<0.0001), 21-carbon steroid hormone metabolism (P=<0.0001), fatty acid beta-oxidation (P=0.04). Pathways related to sugar metabolism were significantly upregulated in smoking patients: galactose metabolism (P=0.003), starch and sucrose metabolism (P=0.007), hexose phosphorylation (P=0.03), sialic acid metabolism (P=0.03). A principal component comprised of the 16 pathway metabolites was significantly associated with overall survival (HR=1.27 per standard deviation, P=0.01, 95% CI: 1.06-1.51) independent of HPV, smoking, tumor site, age, sex, race, and body mass index. Conclusions: Metabolites corresponding to fatty acid, steroid, and sugar metabolism differentiated HPV-related SCCHN from smoking-related SCCHN. They may be clinically informative as prognostic markers of survival. Our novel findings in patient plasma parallel those from HPV positive vs negative SCCHN cell lines, suggesting that metabolites in blood may be putative biomarkers of tumor metabolic activity and thus potentially useful for drug discovery. Citation Format: Ronald C. Eldridge, Karan Uppal, Jonathan Beitler, Kristin Higgins, Evanthia C. Wommack, Dong M. Shin, Nabil F. Saba, Andrew Miller, Deborah W. Bruner, Canhua Xiao. Metabolic differences between human papillomavirus-related and smoking-related squamous cell carcinoma of the head and neck independently predict overall patient survival [abstract]. In: Abstracts: AACR Special Virtual Conference on Epigenetics and Metabolism; October 15-16, 2020; 2020 Oct 15-16. Philadelphia (PA): AACR; Cancer Res 2020;80(23 Suppl):Abstract nr PO-033.

Abstract 2980: Effects of cetuximab and CD-3379 on cytokine/chemokine balance in the tumor micro-environment (TME) of squamous cell carcinoma of the head and neck (SCCHN)

Abstract Background: The Anti-EGFR agent cetuximab has shown promising outcomes and remains to be the only FDA-approved non-immunotherapeutic targeted agent for the treatment of squamous cell carcinoma of the head and neck (SCCHN). There is evidence that immune modulation represents a mechanism by which cetuximab elicits its clinical activity in SCCHN. As resistance inevitably occurs to cetuximab, there is a need to further elucidate the biological mechanisms by which cetuximab affects immune effectors in the tumor microenvironment (TME). We aimed to explore the effect of EGFR inhibition on the cytokine/chemokine balance in the TME. Methods: Three SCCHN cancer cell lines UM-SCC47 (HPV positive), JHU022 (HPV negative), and SCC-1C (HPV negative and resistant to cetuximab) were treated with cetuximab, CD-3379 (a HER3 inhibitor), and their combination. After 48 and/or 72 hours, the supernatants of the treated and untreated cells were collected and subjected to multiplexed immunoassay [Meso Scale Discovery (MSD) U-PLEX Assays] to study the cytokine/chemokine alteration. Changes in immune suppressive chemokines were confirmed by ELISA. A potential effect of a chemokine neutralizing antibody on apoptosis was further evaluated using patient-derived organotypic cancer spheroids (PDOCSs). Results: Our results identified 10 down regulated cytokines/chemokines, including IL6, IL-8, IL-2, IL-12, IL-27, IL-4, IL-5, TGF-β, GM-CSF, and IFN-γ in at least one SCCHN cell line. Three cytokines/chemokines were up regulated, including IL-15, MCP-3, and MCP-1. MCP-1 (CCL2) is a modulator of myeloid-derived suppressor cells (MDSCs). Enhancing MCP-1 by cetuximab and/or CD-3379 in the SCCHN cell lines was confirmed by ELISA. Treating multiple PDOCSs with the same combination along with MCP-1 neutralizing antibody enhanced apoptosis in comparison to cetuximab, CD-3379, or the cetuximab/CD-3379 combination. Conclusions: Our findings suggest that cetuximab in combination with HER3 inhibition affects secretion of cytokines/chemokines which are both immune stimulatory and suppressive in the TME of SCCHN. Alteration of the selected cytokines/chemokines may enhance the clinical activity of EGFR targeting in SCCHN. Citation Format: Dongsheng Wang, Sreenivas Nannapaneni, Gregory B. Lesinski, Dong M. Shin, Nabil F. Saba, Georgia Z. Chen. Effects of cetuximab and CD-3379 on cytokine/chemokine balance in the tumor micro-environment (TME) of squamous cell carcinoma of the head and neck (SCCHN) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2980.

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity.

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors' platinum resistance identifies novel approach to treating these tumors.

Honokiol Radiosensitizes Squamous Cell Carcinoma of the Head and Neck by Downregulation of Survivin.

Purpose: Previous studies revealed diverging results regarding the role of survivin in squamous cell carcinoma of the head and neck (SCCHN). This study aimed to evaluate the clinical significance of survivin expression in SCCHN; the function of survivin in DNA-damage repair following ionizing radiation therapy (RT) in SCCHN cells; and the potential of honokiol to enhance RT through downregulation of survivin.Experimental Design: Expression of survivin in SCCHN patient primary tumor tissues (n = 100) was analyzed and correlated with clinical parameters. SCCHN cell lines were used to evaluate the function of survivin and the effects of honokiol on survivin expression in vitro and in vivoResults: Overexpression of survivin was significantly associated with lymph nodes' metastatic status (P = 0.025), worse overall survival (OS), and disease-free survival (DFS) in patients receiving RT (n = 65, OS: P = 0.024, DFS: P = 0.006) and in all patients with SCCHN (n = 100, OS: P = 0.002, DFS: P = 0.003). In SCCHN cells, depletion of survivin led to increased DNA damage and cell death following RT, whereas overexpression of survivin increased clonogenic survival. RT induced nuclear accumulation of survivin and its molecular interaction with γ-H2AX and DNA-PKCs. Survivin specifically bound to DNA DSB sites induced by I-SceI endonuclease. Honokiol (which downregulates survivin expression) in combination with RT significantly augmented cytotoxicity in SCCHN cells with acquired radioresistance and inhibited growth in SCCHN xenograft tumors.Conclusions: Survivin is a negative prognostic factor and is involved in DNA-damage repair induced by RT. Targeting survivin using honokiol in combination with RT may provide novel therapeutic opportunities. Clin Cancer Res; 24(4); 858-69. ©2017 AACR.

Multilayered Omics-Based Analysis of a Head and Neck Cancer Model of Cisplatin Resistance Reveals Intratumoral Heterogeneity and Treatment-Induced Clonal Selection.

Purpose: Platinum-based drugs, in particular cisplatin (cis-diamminedichloridoplatinum(II), CDDP), are used for treatment of squamous cell carcinoma of the head and neck (SCCHN). Despite initial responses, CDDP treatment often results in chemoresistance, leading to therapeutic failure. The role of primary resistance at subclonal level and treatment-induced clonal selection in the development of CDDP resistance remains unknown.Experimental Design: By applying targeted next-generation sequencing, fluorescence in situ hybridization, microarray-based transcriptome, and mass spectrometry-based phosphoproteome analysis to the CDDP-sensitive SCCHN cell line FaDu, a CDDP-resistant subline, and single-cell derived subclones, the molecular basis of CDDP resistance was elucidated. The causal relationship between molecular features and resistant phenotypes was determined by siRNA-based gene silencing. The clinical relevance of molecular findings was validated in patients with SCCHN with recurrence after CDDP-based chemoradiation and the TCGA SCCHN dataset.Results: Evidence of primary resistance at clonal level and clonal selection by long-term CDDP treatment was established in the FaDu model. Resistance was associated with aneuploidy of chromosome 17, increased TP53 copy-numbers and overexpression of the gain-of-function (GOF) mutant variant p53R248L siRNA-mediated knockdown established a causal relationship between mutant p53R248L and CDDP resistance. Resistant clones were also characterized by increased activity of the PI3K-AKT-mTOR pathway. The poor prognostic value of GOF TP53 variants and mTOR pathway upregulation was confirmed in the TCGA SCCHN cohort.Conclusions: Our study demonstrates a link of intratumoral heterogeneity and clonal evolution as important mechanisms of drug resistance in SCCHN and establishes mutant GOF TP53 variants and the PI3K/mTOR pathway as molecular targets for treatment optimization. Clin Cancer Res; 24(1); 158-68. ©2017 AACR.

Protein methyltransferases and demethylases dictate CD8+ T-cell exclusion in squamous cell carcinoma of the head and neck.

A subset of patients with recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN) benefit from pembrolizumab and nivolumab, but the majority of patients do not probably due to lack of activated cytotoxic CD8+ T-cells in their tumor tissues. Herein, we aim to investigate whether specific protein methyltransferases (PMTs) and demethylases (PDMTs) could play any roles in the CD8+ T-cell exclusion process in HPV-negative SCCHN. RNA sequencing data from the TCGA database were interrogated for HPV-negative SCCHN patients using a 10-gene chemokine signature that classifies SCCHN tissues into CD8+ T-cell inflamed and non-CD8+ T-cell inflamed phenotypes. Among 53 PMT/PDMT genes examined in the TCGA HPV-negative SCCHN database, expression levels of 15 PMT/PDMT genes were significantly negatively correlated with the chemokine signature score and CD8 mRNA expression levels. The expression level of each of these 15 PMT/PDMT genes showed significantly negative correlations with immune-active chemokines, as well as HLA class I and APM molecules. siRNA-mediated knockdown of a candidate PMT, SMYD3, led to upregulation of CXCL9, CXCL10, CXCL11 and TAP1 at mRNA and protein levels in HPV-negative SCCHN cell lines. These findings demonstrate that overexpression of some PMTs and PDMTs seems to be related with the non-CD8+ T-cell inflamed phenotype and may drive CD8+ T-cell exclusion in HPV-negative SCCHN. This study suggests that chromatin modifiers contribute to CD8+ T-cell exclusion and antigen presentation capacity of HPV-negative SCCHN, supporting that targeting of specific PMTs and/or PDMTs could enhance CD8+ T-cell infiltration and increase the proportion of patients that may benefit from immunotherapy.

NLRP3 inflammasome activation promotes inflammation-induced carcinogenesis in head and neck squamous cell carcinoma

BackgroundNLRP3 inflammasome acts as a danger signal sensor that triggers and coordinates the inflammatory response. However, the roles of NLRP3 inflammasome in the tumorigenesis and development of cancer stem cells (CSCs) of squamous cell carcinoma of the head and neck (SCCHN) remain ambiguous.MethodsIn our study, tissue microarrays, ELISA, sphere-forming assay, colony formation assay and Western blot analysis were performed to evaluate the effect of NLRP3 inflammasome on the development of CSCs in human SCCHN tissue specimen, cell lines, and transgenic mouse SCCHN model.ResultsThe components of NLRP3 inflammasome, namely, NLRP3, ASC, Caspase-1, and IL-18 were correlated with CSCs markers BMI1, ALDH1 and CD44 in human SCCHN specimens. Moreover, NLRP3, Caspase-1, IL-1β, and IL-18 were highly expressed in SCCHN cell lines. NLRP3 inflammasome activated by LPS and ATP promoted sphere-forming and colony formation capacities along with an upregulation of BMI1, ALDH1 and CD44. In addition, NLRP3 inflammasome blockade by NLRP3 inhibitor MCC950 reduced sphere and colony number, also decreased the expression of BMI1, ALDH1 and CD44 in SCCHN cell lines. Expression of NLRP3, ASC, Caspase-1, IL-1β, IL-18, BMI1, ALDH1 and CD44 was upregulated in Tgfbr1/Pten 2cKO mouse SCCHN model, and NLRP3 inflammasome expression was closely related to those CSCs makers in mice SCCHN. However, MCC950 treatment reduced the expression of NLRP3 inflammasome, CSCs markers BMI1, ALDH1 and CD44 in Tgfbr1/Pten 2cKO mice SCCHN. In addition, blockade of NLRP3 inflammasome can also delayed the tumor-burdened speed in SCCHN mice.ConclusionsOur study demonstrates that NLRP3 inflammasome was upregulated and associated with the carcinogenesis and CSCs self-renewal activation in SCCHN. NLRP3 inflammasome can be a potential target in the development of novel approaches for head and neck squamous cell carcinoma therapy.

In Vitro and In Vivo Synergistic Antitumor Activity of the Combination of BKM120 and Erlotinib in Head and Neck Cancer: Mechanism of Apoptosis and Resistance

We previously reported that the EGFR-targeted inhibitor erlotinib induces G1 arrest of squamous cell carcinoma of the head and neck (SCCHN) cell lines without inducing significant apoptosis. Large-scale genomic studies suggest that >50% of SCCHN cases have activation of PI3K pathways. This study investigated whether cotargeting of EGFR and PI3K has synergistic antitumor effects and apoptosis induction. We examined growth suppression, apoptosis, and signaling pathway modulation resulting from single and combined targeting of EGFR and PI3K with erlotinib and BKM120, respectively, in a panel of SCCHN cell lines and a xenograft model of SCCHN. In a panel of 12 cell lines, single targeting of EGFR with erlotinib or PI3K with BKM120 suppressed cellular growth without inducing significant apoptosis. Cotargeting of EGFR and PI3K synergistically inhibited SCCHN cell line and xenograft tumor growth, but induced variable apoptosis; some lines were highly sensitive, others were resistant. Mechanistic studies revealed that the combination inhibited both axes of the mTORC1 (S6 and 4EBP1) pathway in apoptosis-sensitive cell lines along with translational inhibition of Bcl-2, Bcl-xL, and Mcl-1, but failed to inhibit p-4EBP1, Bcl-2, Bcl-xL, and Mcl-1 in an apoptosis-resistant cell line. siRNA-mediated knockdown of eIF4E inhibited Bcl-2 and Mcl-1 and sensitized this cell line to apoptosis. Our results strongly suggest that cotargeting of EGFR and PI3K is synergistic and induces apoptosis of SCCHN cell lines by inhibiting both axes of the AKT-mTOR pathway and translational regulation of antiapoptotic Bcl-2 proteins. These findings may guide the development of clinical trials using this combination of agents. Mol Cancer Ther; 16(4); 729-38. ©2017 AACR.

Elevated expression of Derlin-1 associates with unfavorable survival time of squamous cell carcinoma of the head and neck and promotes its malignance

Derlin-1 is over-expressed to function as an oncoprotein in breast, lung and colon cancers. However, the implications of Derlin-1 involved in squamous cell carcinoma of the head and neck (SCCHN) remain unknown. This study aims to investigate the effects of Derlin-1 expression on SCCHN tissues and cells. The potential mechanism of Derlin-1 regulating SCCHN cell proliferation, apoptosis and metastasis was also indicated in this work. Western blot and immunohistochemistry (IHC) assays showed that Derlin-1 was over-expressed in 114 SCCHN samples and five SCCHN cell lines. We found that the expression of Derlin-1 was positively associated with lymph node metastasis, clinical stage and recurrence in our SCCHN patients' samples. Survival analysis indicated that high expression of Derlin-1 was significantly associated with shorter overall survival (OS) and disease-free survival (DFS). Knock down expression of Derlin-1 in SCCHN cell lines was found to inhibit cell proliferation, metastasis and promote cell apoptosis. Further experiments showed that signals of PI3K/Akt, p53 and Smad2/3 may involve in these processes. In all, Derlin-1 might be a novel prognostic marker of SCCHN patients and plays an oncogenic role in SCCHN cell progression.

Inhibition of epithelial-mesenchymal transition by cetuximab via the EGFR-GEP100-Arf6-AMAP1 pathway in head and neck cancer.

Despite improved survival by the addition of a monoclonal antibody against epidermal growth factor receptor (EGFR), cetuximab, to chemotherapy or radiotherapy for squamous cell carcinoma of the head and neck (SCCHN), cetuximab by itself is not a potent antiproliferative agent against SCCHN. We aimed to elucidate working mechanism of cetuximab in SCCHN. The effect of cetuximab on the proliferation, migration, invasion, epithelial-mesenchymal transition, and signaling events downstream of the EGFR were investigated in 4 SCCHN cell lines. The in vivo efficacy of cetuximab was evaluated in a xenotransplant model. Cetuximab inhibited migration, invasion, epithelial-mesenchymal transition, and lymph node metastasis by suppressing EGFR-GEP100-Arf6-AMAP1 pathway, but it did not inhibit cancer cell proliferation. The improved survival by the addition of cetuximab is likely to be attributable to the antiepithelial-mesenchymal transition action of cetuximab via inhibiting EGFR-GEP100-Arf6-AMAP1 pathway. © 2016 Wiley Periodicals, Inc. Head Neck 39: 476-485, 2017.

Abstract 515: Survivin contributes to radiation resistance in head and neck cancer through regulation of DNA damage repair

Abstract Background: A major challenge affecting outcomes of patients with squamous cell carcinomas of the head and neck (SCCHN) is radiation resistance. Overexpression of survivin is associated with radiation resistance and poor survival. Our study objectives were to: 1) evaluate the effects of survivin expression level on radiosensitivity in SCCHN cell lines; 2) identify the effect of survivin on DNA damage repair following radiation exposure in SCCHN cells; 3) evaluate the feasibility and efficacy of the combination therapy of survivin inhibitor YM155 and radiation in SCCHN. Methods: SCCHN cell lines, including JHU-022, PCI-15A and Tu686 were used to evaluate the role of survivin in DNA double strand break (DSB) repair following radiation exposure. To determine whether survivin specifically targets the sites of DNA damage, we performed ChIP assays using PCI-15A cells carrying the DR-GFP homologous recombination reporter. The in vitro effects of YM155 on sensitizing resistant cells to radiation were also evaluated using these cell lines. Results: The fraction surviving radiation was about 2.5-fold greater in PCI-15A and Tu686 cells compared with that in JHU-022 cells. As expected, survivin protein levels were elevated in PCI-15A and Tu686 cells compared with JHU-022 cells, suggesting an inverse correlation between survivin expression and radiosensitivity. Clonogenic survival following radiation exposure was inhibited by depletion of survivin in PCI-15A cells by siRNA, and increased by overexpression of survivin in JHU-022 cells. Inhibition of survivin by YM155 enhances the efficacy of radiation in PCI-15A cells. Immunoblotting revealed that radiation induced nuclear accumulation of survivin and its complex with γ-H2X, and DNA-PKCs in PCI-15A cells, suggesting survivin was involved in DNA damage response and repair induced by radiation. ChIP assay further confirmed that survivin specifically targeted and bound to the DNA DSB site, which is consistent with results obtained from immunofluorescence analysis. Conclusions: Survivin is involved in DNA damage response and repair induced by radiation exposure in SCCHN cells. Inhibition of survivin by YM155 enhances the efficacy of radiation, and may provide a novel therapeutic approach to improve the efficacy of radiotherapy in SCCHN. (This research was supported by the National Cancer Institute award P50 CA128613, and GCC Distinguished Cancer Scholar to Dong M. Shin, Zhuo (Georgia) Chen, and Jonathan J Beitler) Citation Format: Xu Wang, Jonathan J. Beitler, Wen Huang, Guo Chen, Sreenivas Nannapaneni, Nabil F. Saba, Xingming Deng, Zhuo G. Chen, Dong M. Shin. Survivin contributes to radiation resistance in head and neck cancer through regulation of DNA damage repair. [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 515.

Abstract 1196: Combination of neuregulin with EGFR activation signatures predict activity of the anti-ErbB3 antibody KTN3379 in SCCHN

Abstract ErbB3, the kinase-dead member of the EGFR/ErbB family, has been implicated as an oncogenic driver in a number of solid tumor types, including squamous cell carcinoma of the head and neck (SCCHN). However, clinical trials have demonstrated limited responses with certain single agent anti-ErbB3-directed therapies, suggesting that multiple ErbB inhibition and/or biomarker-directed patient selection may be beneficial. The anti-EGFR antibody cetuximab has demonstrated improved overall survival in SCCHN, but the overall response rate is relatively low. Several preclinical studies have suggested that pan-ErbB inhibition may result in improved clinical benefit and additionally, may overcome cetuximab resistance. Here we show that ErbB3 and its ligand neuregulin (NRG) are widely expressed in SCCHN, and that ErbB2, but not EGFR, drives ErbB3 activation in the presence of NRG. Although NRG is required for ErbB3 activation, it is not sufficient to fully predict activity of the anti-ErbB3 antibody KTN3379 in SCCHN models. Metadata analysis of human SCCHN tumors revealed that NRG expression is significantly associated with expression of EGFR ligands amphiregulin (AREG) (P<0.0001; R2 = 0.33) and transforming growth factor α (TGFα) (P<0.0001; R2 = 0.25) but not other EGFR ligands. We demonstrate using NRG-positive cell lines that KTN3379 antitumor activity correlates with the level of secreted AREG and TGFα. Using a proximity-based assay for EGFR homodimerization as a surrogate assay for ligand (AREG or TGFα)-induced EGFR activation, we show that high EGFR homodimer levels correlate with KTN3379 antitumor activity in NRG-positive SCCHN cell lines and primary tumor models in vitro and in vivo. These preclinical studies provide the molecular rationale for combination treatment with KTN3379 and cetuximab in SCCHN patients. We propose that an enrichment strategy for NRG expression and EGFR activation signature may result in better clinical activity in response to treatment with KTN3379 and cetuximab in SCCHN patients. Citation Format: Gwenda F. Ligon, Jay S. Lillquist, Scott B. Seibel, Jerry Wallweber, Veronique Neumeister, David L. Rimm, Theresa M. LaVallee, Diego Alvarado. Combination of neuregulin with EGFR activation signatures predict activity of the anti-ErbB3 antibody KTN3379 in SCCHN. [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 1196.

Abstract C172: Concomitant disruption of WEE1 and AurKA synergistically enhances anti-cancer effects in p53 mutated head and neck squamous cell carcinoma

Abstract Head and neck cancer is a devastating disease which annually affects over half a million patients worldwide. Squamous cell carcinoma of the head and neck (SCCHN), which accounts for approximately 90% of all head and neck cancers, often harbors a disruptive mutation of the TP53 gene. Cells harboring TP53 mutations evade cisplatin-induced cellular senescence with cell cycle arrest in the G2 phase, allowing for DNA repair. Wee1 and Aurora Kinase A (AurKA) are crucial regulators of the mitotic cell cycle including G2/M phases and are significantly activated in SCCHN harboring TP53 mutations. Therefore, we hypothesized that a combination therapy aimed at these synthetic lethal targets, Wee1 and AurKA, would enhance anti-cancer effects and cisplatin sensitivity due to abrogation of G2 arrest concomitant with defects in tumor cell mitotic machinery, which is indeed caused by cisplatin. We tested this hypothesis using assays of cell viability, colony formation, anchorage independent cell growth, and finally a three-dimensional oncosphere formation assay in vitro. The combination index (CI) was calculated according to the Chou-Talalay method (CI<0.8, synergistic; 0.8<CI<1.2, additive; CI>1.2, antagonistic). The cell viability assay indicated that the combination of the Wee1 inhibitor MK-1775 with the AurKA inhibitor MLN8237 exhibited striking synergistic inhibitory effects on the cell growth of SCCHN cell lines including FaDu (TP53 mutation, CI = 0.397004), Detroit562 (TP53 mutation, CI = 0.202677) and UNC-7 (TP53 WT, CI = 0.587106). Consistent with the cell viability data we obtained, we also confirmed this synergistic effect under anchorage dependent and independent cell growth conditions in FaDu and UNC-7 cell lines. Interestingly, this combination dramatically reduced the numbers of a stem cell-like oncosphere formation, showing a more effective combination in comparison to MK-1775 with cisplatin (inhibitory effect (% Vehicle): MK-1775+MLN8238 vs MK-1775+Cisplatin; FaDu = 74% vs 69%; UNC-7 = 43% vs 36%). Moreover, all spheroids exposed to the combination of MK-1775 with MLN8237 did not survive following further incubation under normal cell culture conditions. Induction of apoptosis, as shown gradually increased PARP cleavage at Asp214-Gly215 in FaDu and UNC-7 cells, was demonstrated. Furthermore, this synergistic synthetic lethal effect was not seen in normal human tracheobronchial epithelial (NHTBE) cells in a three-dimensional organotypic (air-liquid interface culture condition) culture system, predicting low toxicity. These results suggest that SCCHN cells, including high-risk TP53 mutations, are sensitive to the combination of MK-1775 and MLN8237 in vitro, thereby supporting the preclinical and further clinical evaluation of MK-1775 in combination with MLN8237 for the treatment of patients with TP53 inactivated HNSCC. Citation Format: Jong Woo Lee, Janaki Parameswaran, Ja Seok Koo, Barbara Burtness. Concomitant disruption of WEE1 and AurKA synergistically enhances anti-cancer effects in p53 mutated head and neck squamous cell carcinoma. [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 C172.

The role of Pyk2 in the CCR7-mediated regulation of metastasis and viability in squamous cell carcinoma of the head and neck cells in vivo and in vitro.

In the present study, we aimed to demonstrate whether praline-rich tyrosine kinase-2 (Pyk2) participates in the chemokine receptor 7 (CCR7) downstream signaling network, and to determine the role of this molecule and the related mechanism in the CCR7-mediated regulation of viability and metastasis in vivo and in vitro of squamous cell carcinoma of the head and neck (SCCHN). We constructed the stable Pyk2 related non-kinase (PRNK)-expressing SCCHN cell line, and examined the viability, apoptosis, migration, invasion and adhesion ability in the transfected and untransfected SCCHN cells. An SCCHN tumor model in nude mice was designed and the tumor growth rate was assayed. E-cadherin and vimentin expression was assessed when Pyk2 was inactivated. We found that the stable PRNK-expressing SCCHN cells exhibited low viability, a high rate of apoptosis, low migratory ability, low invasive ability and low adhesion capacity. In the nude mouse body, the tumors formed by these cells grew slowly when compared to the tumor growth in the control group. When Pyk2 was inactivated, CCR7-induced E-cadherin and vimentin expression levels were altered. Thus, Pyk2 is a key downstream signaling molecules of CCR7 in SCCHN, which promotes SCCHN tumorigenesis and progression.

Abstract 101: WHSC1L1 as a therapeutic target in squamous cell carcinoma of the head and neck

Abstract Background: Squamous cell carcinoma of the head and neck (SCCHN) is a common malignancy with high recurrence rates and poor survival, thus new therapies are eagerly awaited. Protein lysine methyltransferases (PKMTs) have recently become one of the most important targets for drug discovery efforts, but only a few studies have explored their role in the pathogenesis of SCCHN. WHSC1L1, a nuclear SET-Suppressor of variegation 3-9, Enhancer of zeste and Trithorax-domain (NSD) PKMT and chromatin modifier, was reported to be amplified (8p11.23) in 6% of SCCHN tumors. This study aims to elucidate the pathophysiological role of WHSC1L1 as an oncogenic force in SCCHN and provide rationale for the development of inhibitors targeting WHSC1L1. Methods: Cytotoxicity assays (MTTs) were conducted in one HPV-positive and one HPV-negative SCCHN cell line with WHSC1L1-specific siRNAs. Quantitative polymerase chain reaction (qPCR) and Western blotting were performed to examine WHSC1L1 expression levels in 14 SCCHN cell lines in comparison to a normal keratinocyte cell line (KGM). Immunohistochemistry (IHC) for WHSC1L1 in 115 patients with SCCHN and correlation of its expression with H3K36me2 was also performed. To identify candidate substrates that are directly methylated by WHSC1L1, in vitro methyltransferase assays using a recombinant protein library were conducted. Results: siRNA-mediated knockdown of WHSC1L1 caused significant cell death in 2 SCCHN cell lines. Approximately 30% of SCCHN cell lines overexpressed WHSC1L1 compared to normal keratinocytes. WHSC1L1 expression as evaluated by IHC was significantly stronger in SCCHN compared to normal epithelium (Kruskal-Wallis test, p = 0.002) and 24% of SCCHN sections expressed high levels of WHSC1L1, compared to 6% of dysplastic lesions and 0% of normal epithelium sections. Interestingly, no association between WHSC1L1 expression levels and H3K36me2 was observed. Conclusions: WHSC1L1 is genetically altered in multiple cancer types. In SCCHN, it is significantly overexpressed in 24% of the tumors and its knockdown caused significant growth suppression of both HPV-positive and HPV-negative SCCHN cell lines. Taken together, WHSC1L1 merits further investigation as a potential therapeutic target in SCCHN. Citation Format: Vassiliki Saloura, Theodore Vougiouklakis, Mark Lingen, Tanguy Seiwert, Everett Vokes, Yusuke Nakamura, Ryuji Hamamoto. WHSC1L1 as a therapeutic target in squamous cell carcinoma of the head and neck. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 101. doi:10.1158/1538-7445.AM2015-101