CTEN Induces Tumour Cell Invasion and Survival and Is Prognostic in Radiotherapy-Treated Head and Neck Cancer.

Head and neck squamous cell carcinoma (HNSCC) is a heterogenous disease treated with surgery and/or (chemo) radiotherapy, but up to 50% of patients with late-stage disease develop locoregional recurrence. Determining the mechanisms underpinning treatment resistance could identify new therapeutic targets and aid treatment selection. C-terminal tensin-like (CTEN) is a member of the tensin family, upregulated in several cancers, although its expression and function in HNSCC are unknown. We found that CTEN is commonly upregulated in HNSCC, particularly HPV-ve tumours. In vitro CTEN was upregulated in HPV-ve (n = 5) and HPV+ve (n = 2) HNSCC cell lines. Stable shRNA knockdown of CTEN in vivo significantly reduced tumour growth (SCC-25), and functional analyses in vitro showed that CTEN promoted tumour cell invasion, colony formation and growth in 3D-culture (SCC-25, Detroit 562). RNA sequencing of SCC-25 cells following CTEN siRNA knockdown identified 349 differentially expressed genes (logFC > 1, p < 0.05). Gene ontology analysis highlighted terms relating to cell locomotion and apoptosis, consistent with in vitro findings. A membrane-based antibody array confirmed that CTEN regulated multiple apoptosis-associated proteins, including HSP60 and cleaved caspase-3. Notably, in a mixed cohort of HPV+ve and HPV-ve HNSCC patients (n = 259), we found a significant, independent negative association of CTEN with prognosis, limited to those patients treated with (chemo)radiotherapy, not surgery, irrespective of human papillomavirus (HPV) status. These data show that CTEN is commonly upregulated in HNSCC and exerts several functional effects. Its potential role in modulating apoptotic response to therapy suggests utility as a predictive biomarker or radio-sensitising target.

HPV, tumour metabolism and novel target identification in head and neck squamous cell carcinoma.

BACKGROUND: Metabolic changes in tumour cells are used in clinical imaging and may provide potential therapeutic targets. Human papillomavirus (HPV) status is important in classifying head and neck cancers (HNSCC), identifying a distinct clinical phenotype; metabolic differences between these HNSCC subtypes remain poorly understood. METHODS: We used RNA sequencing to classify the metabolic expression profiles of HPV+ve and HPV-ve HNSCC, performed a meta-analysis on FDG-PET imaging characteristics and correlated results with in vitro extracellular flux analysis of HPV-ve and HPV+ve HNSCC cell lines. The monocarboxylic acid transporter-1 (MCT1) was identified as a potential metabolic target and tested in functional assays. RESULTS: Specific metabolic profiles were associated with HPV status, not limited to carbohydrate metabolism. There was dominance of all energy pathways in HPV-negative disease, with elevated expression of genes associated with glycolysis and oxidative phosphorylation. In vitro analysis confirmed comparative increased rates of oxidative phosphorylation and glycolysis in HPV-negative cell lines. PET SUV(max) scores however were unable to reliably differentiate between HPV-positive and HPV-negative tumours. MCT1 expression was significantly increased in HPV-negative tumours, and inhibition suppressed tumour cell invasion, colony formation and promoted radiosensitivity. CONCLUSION: HPV-positive and negative HNSCC have different metabolic profiles which may have potential therapeutic applications.

Targeting the Myofibroblastic Cancer-Associated Fibroblast Phenotype Through Inhibition of NOX4.

Background: Cancer-associated fibroblasts (CAFs) are tumor-promoting and correlate with poor survival in many cancers, which has led to their emergence as potential therapeutic targets. However, effective methods to manipulate these cells clinically have yet to be developed. Methods: CAF accumulation and prognostic significance in head and neck cancer (oral, n = 260; oropharyngeal, n = 271), and colorectal cancer (n = 56) was analyzed using immunohistochemistry. Mechanisms regulating fibroblast-to-myofibroblast transdifferentiation were investigated in vitro using RNA interference/pharmacological inhibitors followed by polymerase chain reaction (PCR), immunoblotting, immunofluorescence, and functional assays. RNA sequencing/bioinformatics and immunohistochemistry were used to analyze NAD(P)H Oxidase-4 (NOX4) expression in different human tumors. NOX4's role in CAF-mediated tumor progression was assessed in vitro, using CAFs from multiple tissues in Transwell and organotypic culture assays, and in vivo, using xenograft (n = 9-15 per group) and isograft (n = 6 per group) tumor models. All statistical tests were two-sided. Results: Patients with moderate/high levels of myofibroblastic-CAF had a statistically significant decrease in cancer-specific survival rates in each cancer type analyzed (hazard ratios [HRs] = 1.69-7.25, 95% confidence intervals [CIs] = 1.11 to 31.30, log-rank P ≤ .01). Fibroblast-to-myofibroblast transdifferentiation was dependent on a delayed phase of intracellular reactive oxygen species, generated by NOX4, across different anatomical sites and differentiation stimuli. A statistically significant upregulation of NOX4 expression was found in multiple human cancers (P < .001), strongly correlating with myofibroblastic-CAFs (r = 0.65-0.91, adjusted P < .001). Genetic/pharmacological inhibition of NOX4 was found to revert the myofibroblastic-CAF phenotype ex vivo (54.3% decrease in α-smooth muscle actin [α-SMA], 95% CI = 10.6% to 80.9%, P = .009), prevent myofibroblastic-CAF accumulation in vivo (53.2%-79.0% decrease in α-SMA across different models, P ≤ .02) and slow tumor growth (30.6%-64.0% decrease across different models, P ≤ .04). Conclusions: These data suggest that pharmacological inhibition of NOX4 may have broad applicability for stromal targeting across cancer types.

Using simulators to teach pediatric airway procedures in an international setting.

INTRODUCTION: There has been a growing shift towards endoscopic management of laryngeal procedures in pediatric otolaryngology. There still appears to be a shortage of pediatric otolaryngology programs and children's hospitals worldwide where physicians can learn and practice these skills. Laryngeal simulation models have the potential to be part of the educational training of physicians who lack exposure to relatively uncommon pediatric otolaryngologic pathology. OBJECTIVES: The objective of this study was to assess the utility of pediatric laryngeal models to teach laryngeal pathology to physicians at an international meeting. METHODS: Pediatric laryngeal models were assessed by participants at an international pediatric otolaryngology meeting. Participants provided demographic information and previous experience with pediatric airways. Participants then performed simulated surgery on these models and evaluated them using both a previously validated Tissue Likeness Scale and a pre-simulation to post-simulation confidence scale. RESULTS: Participants reported significant subjective improvement in confidence level after use of the simulation models (p < 0.05). Participants reported realistic representations of human anatomy and pathology. The models' tissue mechanics were adequate to practice operative technique including the ability to incise, suture, and suspend models. CONCLUSION: The pediatric laryngeal models demonstrate high quality anatomy, which is easy manipulated with surgical instruments. These models allow both trainees and surgeons to practice time-sensitive airway surgeries in a safe and controlled environment.

Pro-migratory and TGF-ß-activating functions of αvß6 integrin in pancreatic cancer are differentially regulated via an Eps8-dependent GTPase switch.

The integrin αvß6 is up-regulated in numerous carcinomas, where expression commonly correlates with poor prognosis. αvß6 promotes tumour invasion, partly through regulation of proteases and cell migration, and is also the principal mechanism by which epithelial cells activate TGF-ß1; this latter function complicates therapeutic targeting of αvß6, since TGF-ß1 has both tumour-promoting and -suppressive effects. It is unclear how these different αvß6 functions are linked; both require actin cytoskeletal reorganization, and it is suggested that tractive forces generated during cell migration activate TGF-ß1 by exerting mechanical tension on the ECM-bound latent complex. We examined the functional relationship between cell invasion and TGF-ß1 activation in pancreatic ductal adenocarcinoma (PDAC) cells, and confirmed that both processes are αvß6-dependent. Surprisingly, we found that cellular functions could be biased towards either motility or TGF-ß1 activation depending on the presence or absence of epidermal growth factor receptor pathway substrate 8 (Eps8), a regulator of actin remodelling, endocytosis, and GTPase activation. Similar to αvß6, we found that Eps8 was up-regulated in >70% of PDACs. In complex with Abi1/Sos1, Eps8 regulated αvß6-dependent cell migration through activation of Rac1. Down-regulation of Eps8, Sos1 or Rac1 suppressed cell movement, while simultaneously increasing αvß6-dependent TGF-ß1 activation. This latter effect was modulated through increased cell tension, regulated by Rho activation. Thus, the Eps8/Abi1/Sos1 tricomplex acts as a key molecular switch altering the balance between Rac1 and Rho activation; its presence or absence in PDAC cells modulates αvß6-dependent functions, resulting in a pro-migratory (Rac1-dependent) or a pro-TGF-ß1 activation (Rho-dependent) functional phenotype, respectively. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Surgical safety issues relating to the use of diathermy in patients with cochlear implants: the patient's perspective.

OBJECTIVES: The number of cochlear implant recipients throughout the world is set to increase markedly. Surgical diathermy used inappropriately in the head and neck region can be damaging to implant electronics and may irreversibly damage the remaining auditory neural pathways. Safety guidelines have been published but many non-implant surgeons are unaware of their existence. We aimed to examine this issue from the patient's perspective. METHODS: A questionnaire was supplied to 50 adults and the parents of 50 implanted children registered at the South of England Cochlear Implant Centre. RESULTS: Adults Forty-six percent felt that non-implant surgeons would be aware of the diathermy restrictions. Only one patient had undergone subsequent surgery. Eighty-six percent still possess their implant identification (ID) card, and 71% carry it with them. Seventy-seven percent felt that if they required surgery they would show their implant ID card and raise the diathermy issue. Parents Although 76% of parents believed that surgeons would be unaware of the diathermy restrictions, none of the 12% of parents whose children underwent subsequent surgery had highlighted the issue to their surgeon. Eighty-four percent of the parents/children possessed their ID card. While only 8% of parents ensured that their child carried it at all times, a further 12% reported in free text that they carry the card on behalf of their children. CONCLUSION: Diathermy use in cochlear implant recipients is a significant patient safety issue. There is a role for further education of patients and surgeons, for better utilization of the ID card, and for increased clarity on manufacturers' websites.