Proton Treatment Suppresses Exosome Production in Head and Neck Squamous Cell Carcinoma

Proton therapy (PT) is emerging as an effective and less toxic alternative to conventional X-ray-based photon therapy (XRT) for patients with advanced head and neck squamous cell carcinomas (HNSCCs) owing to its clustered dose deposition dosimetric characteristics. For optimal efficacy, cancer therapies, including PT, must elicit a robust anti-tumor response by effector and cytotoxic immune cells in the tumor microenvironment (TME). While tumor-derived exosomes contribute to immune cell suppression in the TME, information on the effects of PT on exosomes and anti-tumor immune responses in HNSCC is not known. In this study, we generated primary HNSCC cells from tumors resected from HNSCC patients, irradiated them with 5 Gy PT or XRT, and isolated exosomes from cell culture supernatants. HNSCC cells exposed to PT produced 75% fewer exosomes than XRT- and non-irradiated HNSCC cells. This effect persisted in proton-irradiated cells for up to five days. Furthermore, we observed that exosomes from proton-irradiated cells were identical in morphology and immunosuppressive effects (suppression of IFN-γ release by peripheral blood mononuclear cells) to those of photon-irradiated cells. Our results suggest that PT limits the suppressive effect of exosomes on cancer immune surveillance by reducing the production of exosomes that can inhibit immune cell function.

Rapid purification and multiparametric characterization of circulating small extracellular vesicles utilizing a label-free lab-on-a-chip device

Nano-scale extracellular vesicles are lipid-bilayer delimited particles that are naturally secreted by all cells and have emerged as valuable biomarkers for a wide range of diseases. Efficient isolation of small extracellular vesicles while maintaining yield and purity is crucial to harvest their potential in diagnostic, prognostic, and therapeutic applications. Most conventional methods of isolation suffer from significant shortcomings, including low purity or yield, long duration, need for large sample volumes, specialized equipment, trained personnel, and high costs. To address some of these challenges, our group has reported a novel insulator-based dielectrophoretic device for rapid isolation of small extracellular vesicles from biofluids and cell culture media based on their size and dielectric properties. In this study, we report a comprehensive characterization of small extracellular vesicles isolated from cancer-patients' biofluids at a twofold enrichment using the device. The three-fold characterization that was performed using conventional flow cytometry, advanced imaging flow cytometry, and microRNA sequencing indicated high yield and purity of the isolated small extracellular vesicles. The device thus offers an efficient platform for rapid isolation while maintaining biomolecular integrity.

Small extravesicular microRNA in head and neck squamous cell carcinoma and its potential as a liquid biopsy for early detection

BACKGROUND

The objective was to assess secretion of small extracellular vesicular microRNA (exo-miRNA) in head and neck squamous cell carcinoma (HNSCC) according to human papillomavirus (HPV) status, and determine the translational potential as a liquid biopsy for early detection.

METHODS

This study employed a combination of cell culture and case-control study design using archival pretreatment serum. Small extracellular vesicles (sEV) were isolated from conditioned culture media and human serum samples via differential ultracentrifugation. miRNA-sequencing was performed on each sEV isolate.

RESULTS

There were clear exo-miRNA profiles that distinguished HNSCC cell lines from nonpathologic oral epithelial control cells. While there was some overlap among profiles across all samples, there were apparent differences in exo-miRNA profiles according to HPV-status. Importantly, differential exo-miRNA profiles were also apparent in serum from early-stage HNSCC cases relative to cancer-free controls.

CONCLUSIONS

Our findings indicate that exo-miRNA are highly dysregulated in HNSCC and support the potential of exo-miRNA as biomarkers for HNSCC.

Stable methylation loci are associated with systolic blood pressure in a Croatian island population

Background: The objective was to identify stable and dynamic DNA methylation loci associated with cardiometabolic traits among an adult population from the Croatian island of Hvar. Materials & methods: An epigenome-wide association study was conducted using peripheral blood longitudinally collected at two time points 10 years apart via Infinium MethylationEPIC beadarray (n = 112). Stable and dynamic loci were identified using linear mixed models. Associations between cardiometabolic traits and loci were assessed using linear models. Results: 22 CpG loci were significantly associated with systolic blood pressure. Twenty were stable and two were dynamic. Conclusion: Multiple genes may be involved in the determination of systolic blood pressure level via stable epigenetic programming, potentially established earlier in life.

DNA methylation-derived systemic inflammation indices and their association with oropharyngeal cancer risk and survival

BACKGROUND

Head and neck squamous cell carcinomas are associated with systemic inflammation (SI). We evaluated whether DNA methylation-derived SI (mdSI) indices are associated with oropharyngeal cancer risk and survival.

METHODS

Ninety-four oropharyngeal squamous cell carcinoma (OPSCC) cases and 57 controls with DNA methylation data were included. Logistic regression analysis and survival analysis were performed to test the association of mdSI indices with OPSCC risk and survival.

RESULTS

Higher methylation-derived neutrophil-to-lymphocyte ratio (mdNLR) was associated with increased risk of OPSCC (OR = 1.21, 95%CI: 1.11-1.40) while no association was found with methylation-derived lymphocyte-to-monocyte ratio (mdLMR). For 5-year overall survival, higher mdLMR was significantly associated with decreased risk of death (HR = 0.25, 95%CI: 0.10-0.64) while the converse was observed for mdNLR (HR = 2.48, 95%CI: 1.04-5.92).

CONCLUSION

We observed an association between mdSI indices and OPSCC risk and 5-year overall survival. It is possible to use mdLMR as an independent prognostic factor for OPSCC.

Human Papillomavirus and Survival of Sinonasal Squamous Cell Carcinoma Patients: A Systematic Review and Meta-Analysis

Simple Summary

Human papillomavirus (HPV) has been associated with multiple cancers in the anogenital and upper aerodigestive tracts. In the head and neck region, HPV-positive cancers are common in oropharynx, with rising incidence and a well-established association with more favorable patient outcomes. However, the relationship with prognosis of sinonasal squamous cell carcinoma (SNSCC) has been much less often studied and is presently unclear. To better elucidate this relationship, we performed a systematic review and meta-analysis of the biomedical literature to determine the aggregate effect across studies. In doing so, we observed significantly better overall survival associated with HPV-positive SNSCC. Therefore, we conclude that HPV testing may be useful for determining patient prognosis and potentially guiding treatment decisions.

Abstract

Human papillomavirus (HPV) is detectable in a subset of sinonasal squamous cell carcinoma (SNSCC), but the impact on patient outcomes is presently unclear due to a modest number of studies with limited statistical power. Therefore, we conducted a systematic review and meta-analysis to better clarify this relationship. A PubMed search was conducted to identify all studies reporting on overall (OS) or disease-free survival (DFS) for SNSCC by HPV status. Hazard ratios (HR) and corresponding 95% confidence intervals (CI) were extracted or, when not provided, indirectly estimated from each manuscript. Summary survival curves for 5-year OS and estimating survival probability by HPV status at pre-specified time intervals from study-specific Kaplan-Meier curves generated 2-year DFS. Log HRs and log CIs were combined across studies to generate summary estimates and a corresponding 95% CIs for OS and DFS. We identified ten unique studies reporting on OS and four for DFS. We observed a significant association between HPV and OS (summary HR = 0.51, 95% CI: 0.38–0.70) with relatively low heterogeneity between studies. These results indicate that HPV is a significant predictor of more favorable survival for SNSCC, and thus may be a useful biomarker for prognostication and, potentially, treatment modulation.

Comparability of the small RNA secretome across human biofluids concomitantly collected from healthy adults

Small extracellular vesicles (sEV) are nano-sized (40–150 nm), membrane-encapsulated vesicles that are released by essentially all cells into the extracellular space and function as intercellular signaling vectors through the horizontal transfer of biologic molecules, including microRNA (miRNA) and other small non-coding RNA (ncRNA), that can alter the phenotype of recipient cells. sEV are present in essentially all extracellular biofluids, including serum, urine and saliva, and offer a new avenue for discovery and development of novel biomarkers of various disease states and exposures. The objective of this study was to systematically interrogate similarities and differences between sEV ncRNA derived from saliva, serum and urine, as well as cell-free small ncRNA (cf-ncRNA) from serum. Saliva, urine and serum were concomitantly collected from 4 healthy donors to mitigate potential bias that can stem from interpersonal and temporal variability. sEV were isolated from each respective biofluid, along with cf-RNA from serum. sEV were isolated from the respective biofluids via differential ultracentrifugation with a 30% sucrose cushion to minimize protein contamination. Small RNA-sequencing was performed on each sample, and cluster analysis was performed based on ncRNA profiles. While some similarities existed in terms of sEV ncRNA cargo across biofluids, there are also notable differences in ncRNA class and ncRNA secretion, with sEV in each biofluid bearing a unique ncRNA profile, including major differences in composition by ncRNA class. We conclude that sEV ncRNA cargo varies according to biofluid, so thus should be carefully selected and interpreted when designing or contrasting translational or epidemiological studies.

Firefighter occupation is associated with increased risk for laryngeal and hypopharyngeal squamous cell carcinoma among men from the Greater Boston area

OBJECTIVE

Firefighters are exposed to a wide variety of carcinogens during the line of duty, including several associated with head and neck cancer. Existing studies assessing head and neck cancer risk with firefighting have predominately included occupational cohorts or registry data, which are limited by inability to adjust for smoking and alcohol consumption-major risk factors for head and neck cancer. Our objective was to assess the risk of head and neck cancer among men with an occupational history as a firefighter.

METHODS

This work was conducted using male subjects from a large population-based case-control study of head and neck cancer from the greater Boston area using self-reported occupational history (718 cases and 905 controls).

RESULTS

An occupational history as a firefighter was reported for 11 cases and 14 controls. Although no significant association was observed overall, we observed substantial increased risk for hypopharyngeal and laryngeal squamous cell carcinoma among professional municipal firefighters who had a light or no smoking history (OR=8.06, 95% CI 1.74 to 37.41), with significantly increasing risk per decade as a firefighter (OR=2.10, 95% CI 1.06 to 4.14).

CONCLUSION

Professional municipal firefighters may be at increased risk for hypopharyngeal and laryngeal squamous cell carcinoma due to carcinogenic exposures encountered during the line of duty.

Rapid and label-free isolation of small extracellular vesicles from biofluids utilizing a novel insulator based dielectrophoretic device

Exosomes are nano-scale membrane-encapsulated vesicles produced by the majority of cells and have emerged as a rich source of biomarkers for a wide variety of diseases. Although many approaches have been developed for exosome isolation from biofluids, most of them have substantial shortcomings including long processing time, inefficiency, high cost, lack of specificity and/or surface marker-dependency. To address these issues, here we report a novel insulator-based dielectrophoretic (iDEP) device predicated on an array of borosilicate micropipettes to rapidly isolate exosomes from conditioned cell culture media and biofluids, such as plasma, serum, and saliva. The device is capable of exosome isolation from small sample volumes of 200 μL within 20 minutes under a relatively low (10 V cm-1) direct current (DC). This device is easy to fabricate thus, no cleanroom facility and expensive equipment are needed. Therefore, the iDEP device offers a rapid and cost-effective strategy for exosome isolation from biofluids in timely manner while maintaining the yield and purity.

Abstract 5038: Chrysotile asbestos fibers in tissue adjacent to laryngeal squamous cell carcinoma in cases with a history of occupational asbestos exposure

Asbestos describes a group of naturally occurring fibrous silicate mineral compounds. Its use dates back thousands of years but became widespread in the late 19th century through the late 20th century due to its favorable industrial properties, including its strength, flexibility and thermal properties, with peak use in the United States occurring in the 1970s. Asbestos has been associated with a number of chronic respiratory diseases, including malignancy, and was first linked to mesothelioma and lung cancer in the early to mid part of the 20th century. Despite the known health risks, asbestos is not universally banned and is still in use in many countries (including the United States), with an estimated 125 million occupationally-exposed individuals worldwide. In addition to mesothelioma and lung cancer, asbestos has also been implicated as a risk factor for squamous cancers involving the upper airway, in particular laryngeal and pharyngeal carcinoma, as indicated by recent meta-analyses; however, evidence for the latter associations is based solely on epidemiologic data from observational studies. The primary objective of this work was to attempt to strengthen the evidence via empirical demonstration of persistent asbestos fibers embedded in the tissue surrounding the tumor, thus providing a more definitive biological link between exposure and disease. Six HPV-negative laryngeal and pharyngeal squamous cell carcinoma cases were selected from a large population-based case-control study of head and neck cancer, plus one case with no occupational exposure history as a control. Briefly, detailed occupational history was available for 1,056 head and neck cancer cases enrolled through major teaching hospitals located in Boston, Massachusetts. Occupational data was reviewed to identify those with an occupational history of asbestos exposure. Tissue cores were obtained from adjacent non-neoplastic tissue in tumor blocks from the initial primary tumor resection from a subset of 6 cases with a history of occupational-asbestos exposure and 1 case with no reported occupational exposure (control). A count of asbestos fibers >5um was performed on the cores from each case at Duke University using a scanning electron microscope equipped with an energy dispersive x-ray analyzer (EDXA). Despite the low volume of input tissue, chrysotile asbestos fibers were identified in 3/6 of evaluated cases with a history of occupational asbestos exposure; all 3 cases had tumors originating in the larynx. This is the first study to demonstrate the presence of asbestos fibers in the larynx of cases with laryngeal squamous cell carcinoma, adding an additional line of physical evidence implicating asbestos as an etiologic factor for laryngeal squamous cell carcinoma.

Citation Format: Stephanie K. Wronkiewicz, Victor Roggli, Damaris Kuhnell, Rondi A. Butler, Karl T. Kelsey, Scott M. Langevin. Chrysotile asbestos fibers in tissue adjacent to laryngeal squamous cell carcinoma in cases with a history of occupational asbestos exposure [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5038.

Comprehensive mapping of the methylation landscape of 16 CpG-dense regions in oral and pharyngeal squamous cell carcinoma

Aim: The goal of this study was to comprehensively interrogate and map DNA methylation across 16 CpG-dense regions previously associated with oral and pharyngeal squamous cell carcinoma (OPSCC). Materials & methods: Targeted multiplex bisulfite amplicon sequencing was performed on four OPSCC cell lines and primary non-neoplastic oral epithelial cells. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed for a subset of associated genes. Results: There was clear differential methylation between one or more OPSCC cell lines and control cells for the majority of CpG-dense regions. Conclusion: Targeted multiplex bisulfite amplicon sequencing allowed us to efficiently map methylation across the entire region of interest with a high degree of sensitivity and helps shed light on novel differentially methylated regions that may have value as biomarkers of OPSCC.

Balancing yield, purity and practicality: a modified differential ultracentrifugation protocol for efficient isolation of small extracellular vesicles from human serum

Ultracentrifugation remains the gold standard for isolation of small extracellular vesicles (sEV), particularly for cancer applications. The objective of this study was to determine if a widely used ultracentrifugation protocol for isolation of serum sEV could be modified to reduce the number of ultracentrifugation cycles and increase efficiency, while maintaining equal or better sample purity and yield. Serum was obtained from two healthy subjects. sEVs were isolated from 1 mL aliquots using three different ultracentrifugation protocols. Co-isolation of RNA carrier protein was assessed by performing Western blots for ApoA-I, ApoB, and Ago2. Small RNA-sequencing was performed on the sEV isolates, and differential detection of small ncRNA was compared across isolation protocols. Reduction from three- to two-ultracentrifuge cycles with no sucrose cushion resulted in a much higher sEV yield but also had the highest levels of lipoprotein and Ago2 contamination. However, the two-ultracentrifugation cycle protocol that incorporated a 30% sucrose cushion into the first cycle resulted in slightly higher sEV yields with lower levels of protein contamination compared to the lengthier three-ultracentrifugation cycle approach, therefore presenting a more efficient alternative approach for isolation of serum sEVs. It was also notable that there were some differences in sEV ncRNA cargo according to protocol, although it was less than expected given the differences in co-isolated RNA carrier proteins. Our results suggest that use of the modified serum sEV isolation protocol with two ultracentrifugation cycles and incorporating a 30% sucrose cushion offers a more efficient approach in terms of efficiency and purity.

Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines for the field in 2014. We now update these "MISEV2014" guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points.

Differential expression and prognostic value of long non-coding RNA in HPV-negative head and neck squamous cell carcinoma

BACKGROUND

Long non-coding RNA (lncRNA) has emerged as a new avenue of interest due to its various biological functions in cancer. Abnormal expression of lncRNA has been reported in other malignancies but has been understudied in head and neck squamous cell carcinoma (HNSCC).

METHODS

The lncRNA expression was interrogated via quantitative real-time polymerase chain reaction (qRT-PCR) array for 19 human papillomavirus (HPV)-negative HNSCC tumor-normal pairs. The Cancer Genome Atlas (TCGA) was used to validate these results. The association between differentially expressed lncRNA and survival outcomes was analyzed.

RESULTS

Differential expression was validated for 5 lncRNA (SPRY4-IT1, HEIH, LUCAT1, LINC00152, and HAND2-AS1). There was also an inverse association between MEG3 expression (not significantly differentially expressed in TCGA tumors but highly variable expression) and 3-year recurrence-free survival (RFS).

CONCLUSION

We identified and validated differential expression of 5 lncRNA in HPV-negative HNSCC. Low MEG3 expression was associated with favorable 3-year RFS, although the significance of this finding remains unclear.

Abstract 26: Exosomal microRNA as salivary biomarkers of head and neck squamous cell carcinoma

Head and neck cancer is the 10th most common cancer overall and 5th most common among men in the United States, the vast majority of which are squamous cell carcinoma (HNSCC). Despite approximately two-thirds of cases being diagnosed at an advanced stage, the only routine screening approach currently in widespread use is visual inspection and palpation, which is provided by dentists and clinicians on an opportunistic basis, lacks sensitivity, and varies according to the skill of the clinician. This underscores the urgent and compelling need for establishment of novel and effective biomarkers to facilitate early detection. Exosomes may offer a new avenue for discovery and development of novel biomarkers of HNSCC. These nanosized (40-150 nm), membrane-encapsulated vesicles are released by both normal and malignant cells into the extracellular space and function as intercellular signaling vectors through the horizontal transfer of biologic molecules, including microRNA (miRNA), which can affect the phenotype of recipient cells. Importantly, exosomes are present in essentially all extracellular biofluids, including saliva, and thus can readily be collected by noninvasive means. Through previous cell culture work, we observed striking differences in exosomal miRNA secreted by HNSCC cells relative to healthy oral epithelial cells, with a high degree of overlap in exosomal miRNA profiles across HNSCC cell lines. Although salivary exosomes have been theorized to be a potentially powerful biomarker source for HNSCC, there has been an extreme paucity of work conducted in this arena. To begin to address this question, we conducted a small pilot study in which we collected 2-mL whole-saliva samples from 5 HNSCC cases (collected prior to initiation of treatment) and 5 cancer-free controls. Exosomes were isolated from each saliva sample via differential ultracentrifugation, and total RNA was extracted for miRNA-sequencing (miRNA-seq), which was performed by the University of Cincinnati Genomics, Epigenomics & Sequencing Core (GESC). The number of reads for each sample during miRNA-seq ranged from 1.6 million to 27.4 million reads (median = 12.4 million). After aligning the reads to all human miRNA sequences catalogued in miRBase, there were a total of 1,334 mature miRNA transcripts detected across samples, with 307 transcripts (12%) detected solely in salivary exosomes from cases. Moreover, despite the small sample size of the pilot study, we observed significant differential exosomal secretion of miR-10b-5p (p = 0.006), with transcripts present at relatively high levels in salivary exosomes from 3 of the 5 cases but none detected in those from the 5 controls. We also preliminarily assessed the translational potential of 8 miRNA transcripts that were solely and universally expressed by our HNSCC cell lines (i.e. not secreted by healthy oral epithelial cells) in our previous cell culture work using the salivary exosome miRNA-seq data for the 5 cases and 5 controls. All 8 transcripts were detected in salivary exosomes obtained from the 5 HNSCC cases. In particular, miR-486-5p and miR-486-3p showed considerable promise, with 40% of cases expressing drastically higher levels of these transcripts relative to controls. When either miR-486-5p or miR-486-3p was combined with miR-10b-5p, the substantial separation of these markers could clearly distinguish 80% (4/5) of the HNSCC cases from controls. These findings demonstrate the potential of salivary miRNA as biomarkers of HNSCC and highlight the necessity of further workup and validation in full-scale studies involving human saliva.

Citation Format: Scott M. Langevin, Damaris Kuhnell, Xiang Zhang, Trisha M. Wise-Draper, Keith A. Casper. Exosomal microRNA as salivary biomarkers of head and neck squamous cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 26.

Abstract 1797: EGFR as a marker for head and neck squamous cell carcinoma-derived small extracellular vesicles

Head and neck cancer will account for an estimated 61,760 new cancer cases and 13,190 cancer-related deaths in the United States in 2016, the majority of which (> 90%) will be squamous cell carcinoma (HNSCC). The prognosis for HNSCC is relatively poor, with an overall 5-year survival around 60%, and the outlook worsens with increasing stage at diagnosis, which is problematic since about two-thirds of patients present with advanced stage disease. This underscores the urgent need for discovery, development and translation of novel biomarkers to facilitate early detection of HNSCC and bolster the chance for positive patient outcomes. Exosomes are nano-sized (40-150 nm) membrane-encapsulated vesicles that may offer a new avenue for discovery and development of novel HNSCC biomarkers. However, they are released by essentially all cells, both normal and malignant, into the extracellular space, resulting in a noisy environment in biofluids from the perspective of biomarker measurement. As such, a membrane-bound surface marker that allows for enrichment for cancer-derived exosomes in patient samples would provide a clear benefit. Epidermal growth factor receptor (EGFR), which belongs to the ErbB/HER family of receptor tyrosine kinases, localizes to the plasma membrane and is over-expressed in as much as 90% of HNSCC tumors. Therefore, we hypothesized that EGFR will be over-represented on membranes of HNSCC-derived exosomes and thus may offer utility as a surface marker for detection and/or enrichment. To test this, we cultured an HNSCC cell line that over-expresses EGFR (FaDu), EGFR-deficient SW620 colorectal adenocarcinoma cells, and primary human oral epithelial cells pooled from 3 healthy donors. Cells were cultivated in supplier-recommended media with 10% fetal bovine serum (FBS) that was super-depleted of exosomes via 18 hour ultracentrifugation at 100,000g and 1% penicillin/streptomycin at 37°C with 5% CO2 in 150 cm2 flasks with 25mL media. After reaching 80-90% confluence, media was harvested, and exosomes were isolated and purified via differential ultracentrifugation. Exosome isolates were whole-mounted on carbon grids, Immuno-Gold labeled with anti-EGFR, and imaged on a JEOL JEM-1230 transmission electron microscope (Immuno-EM); anti-nucleoporin 153 (NUP-153), which localizes to the nucleus, was used as a negative control. Immuno-EM images indicate abundant EGFR expression on exosomes secreted by FaDu HNSCC cells, but EGFR is not detectable on the exosomes secreted by the oral epithelial cells from healthy donors. These results indicate that EGFR may offer utility for enrichment for HNSCC-derived exosomes in human biofluid isolates using magnetic beads or flow cytometry.

Citation Format: Jenna A. Dombroski, Damaris Kuhnell, Susan Kasper, Scott M. Langevin. EGFR as a marker for head and neck squamous cell carcinoma-derived small extracellular vesicles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1797. doi:10.1158/1538-7445.AM2017-1797

Immune Response to HPV16 E6 and E7 Proteins and Patient Outcomes in Head and Neck Cancer

Importance

Pathology-based measures of human papillomavirus (HPV) status are routinely obtained in the care of head and neck cancer and are clearly associated with patient outcome for cancers of the oropharynx. However, it is unclear if HPV status is of high value for cancers of the larynx and oral cavity. In addition, it is possible to assess HPV infection using serology-based methods; however, the suitability of this pathology-independent measure for predicting patient outcome in head and neck cancer is unknown.

Objective

To investigate whether immunologic response to HPV16 is associated with patient survival across anatomic sites, independent of smoking and drinking history.

Design, Setting, and Participants

This was a population-based study of 1054 patients with head and neck cancer in the greater Boston, Massachusetts, area (1999-2003, 2006-2011).

Main Outcomes and Measures

All-cause survival in relation to HPV16 E6 and E7 seropositivity.

Results

The 1054 patients reflected the demographics of those treated in this timeframe (75% male; mean age, 59 years). Seropositivity was very strongly associated with improved survival overall (hazard ratio HR], 0.33; 95% CI, 0.24-0.45; P < .001), with no evidence that the magnitude of immune response, as assessed by titer levels, effected outcome. Seropositivity was associated with improved patient survival across all head and neck cancer sites: HR for oropharynx cancer, 0.26; 95% CI, 0.18-0.39; for oral cavity cancer, 0.45; 95% CI, 0.18-0.80; and for larynx cancer, 0.29; 95% CI, 0.10-0.85. In addition, the associations with seropositivity were similar across smoking and/or drinking exposure groups: HRfor low exposure, 0.52; 95% CI, 0.20-1.36; for moderate exposure, 0.42; 95% CI, 0.25-0.70; for heavy exposure, 0.51; 95% CI, 0.36-0.73. In a subset of 162 patients with both HPV serology and p16 immunohistochemical (IHC) measures available, both measures were similarly associated with survival in the oropharynx (HR for serology, 0.16; 95% CI, 0.03-0.47; for p16 measures, 0.16; 95% CI, 0.03-0.46), whereas only serology was associated with outcome when considering all head and neck cancer cases (HR for serology,0.49; 95% CI, 0.23-1.04; for p16, 0.65; 95% CI, 0.30-1.42).

Conclusions and Relevance

Collectively, these data suggest that a positive serologic response to HPV16 oncoproteins may be the best approach to assess HPV-disease for clinical outcome because it is associated with survival for all types of disease and is a marker that is not dependent on pathology material.

Abstract 961: Comprehensive catalog of culture-derived exosomal microRNA cargo from 4 discrete head and neck carcinoma cell lines

Background: Exosomes are nano-sized (40-100 nm), membrane encapsulated vesicles that are released by cells into the extracellular space and function as intercellular signaling vectors through the horizontal transfer of biologic molecules, including non-coding RNA. MicroRNA (miRNA) are small (18-25 nucleotides in length), evolutionarily conserved, non-coding RNA molecules that are involved in regulation of gene expression in essentially all eukaryotic organisms through post-transcriptional degradation and translational inhibition of messenger RNA (mRNA). The purpose of this study was to catalog exosomal miRNA cargo that are differentially secreted from head and neck squamous cell carcinoma (HNSCC) cells in vitro using Next Generation miRNA-sequencing.

Methods: We obtained 4 commercially available HNSCC cell lines: (1) H413 (female, buccal); (2) Detroit 562 (female, pharynx metastatic to pleura); (3) FaDu (male, hypopharynx) and (4) Cal 27 (male, tongue). We additionally obtained HGEPp primary human gingival epithelial cells (pooled from 3 healthy female donors) for comparison. Cells were cultivated in supplier-recommended media with 10% fetal bovine serum (FBS) that was super-depleted of exosomes via 18 hour ultracentrifugation at 100,000g and 1% penicillin/streptomycin at 37°C with 5% CO2 in 150 cm2 flasks with 25mL media. To achieve adequate volume for exosome isolation (50mL), cells were cultured in 2-pair sets of flasks in triplicate (6 flasks total per cell line). Media was collected when cells reached 80-90% confluence. Exosomes were isolated and purified from exosome-depleted cell culture media by differential ultracentrifugation and the presence of purified exosomes was verified via nanoparticle tracking analysis (NTA) using a NanoSight NS300 instrument. Total RNA was extracted from each exosome pellet using the miRNeasy Micro kit, and Next Generation miRNA-sequencing was subsequently performed by the University of Cincinnati Genomics, Epigenomics and Sequencing Core (Cincinnati, OH) using the Illumina HiSeq platform. Differential exosomal miRNA secretion was assessed between each HNSCC cell line and the non-pathologic gingival epithelial control cells, adjusting for false-discovery rate using the Benjamini and Hochberg method.

Results: We observed 93 miRNA transcripts that were differentially secreted (Q &lt; 0.05) in exosomes derived from at least one of the HNSCC cell lines relative to the non-pathologic epithelial control cells; 23 miRNA transcripts were differentially secreted by all 4 cell-lines.

Conclusions: This provides evidence for differential secretion of miRNA in HNSCC-derived exosomes. These exosomal miRNA warrant further evaluation as potential biomarkers for HNSCC.

Citation Format: Scott M. Langevin, Damaris Kuhnell, Tess L. Parry, Jacek Biesiada, Xiang Zhang, Mario Medvedovic, Susan Kasper. Comprehensive catalog of culture-derived exosomal microRNA cargo from 4 discrete head and neck carcinoma cell lines. [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 961.

CpG island methylation profile in non-invasive oral rinse samples is predictive of oral and pharyngeal carcinoma

BACKGROUND

There are currently no screening tests in routine use for oral and pharyngeal cancer beyond visual inspection and palpation, which are provided on an opportunistic basis, indicating a need for development of novel methods for early detection, particularly in high-risk populations. We sought to address this need through comprehensive interrogation of CpG island methylation in oral rinse samples.

METHODS

We used the Infinium HumanMethylation450 BeadArray to interrogate DNA methylation in oral rinse samples collected from 154 patients with incident oral or pharyngeal carcinoma prior to treatment and 72 cancer-free control subjects. Subjects were randomly allocated to either a training or a testing set. For each subject, average methylation was calculated for each CpG island represented on the array. We applied a semi-supervised recursively partitioned mixture model to the CpG island methylation data to identify a classifier for prediction of case status in the training set. We then applied the resultant classifier to the testing set for validation and to assess the predictive accuracy.

RESULTS

We identified a methylation classifier comprised of 22 CpG islands, which predicted oral and pharyngeal carcinoma with a high degree of accuracy (AUC = 0.92, 95 % CI 0.86, 0.98).

CONCLUSIONS

This novel methylation panel is a strong predictor of oral and pharyngeal carcinoma case status in oral rinse samples and may have utility in early detection and post-treatment follow-up.

Occupational asphalt is not associated with head and neck cancer

BACKGROUND

Epidemiologic studies that evaluate the relationship between occupational asphalt exposure and head and neck cancer have had a limited ability to control for known risk factors such as smoking, alcohol and human papillomavirus (HPV).

AIMS

To better elucidate this relationship by including known risk factors in a large case-control study of head and neck squamous cell carcinoma (HNSCC) from the greater Boston area.

METHODS

We analysed the relationship between occupational asphalt exposure and HNSCC among men in the Greater Boston area of Massachusetts. Analyses were conducted using unconditional multivariable logistic regression, performed with adjustments for age, race, education, smoking, alcohol consumption and HPV serology.

RESULTS

There were 753 cases and 913 controls. No associations between HNSCC and occupational asphalt exposure (neither among ever-exposed nor by occupational duration) were observed for exposures in any occupation or those restricted to the construction industry. We also observed no associations in subgroup analyses of never-smokers and ever-smokers. Adjusting for known risk factors further reduced the estimated effect of asphalt exposure on HNSCC risk.

CONCLUSIONS

We found no evidence for an association between occupational asphalt exposure and HNSCC. The null findings from this well-controlled analysis could suggest that the risk estimates stemming from occupational cohort studies may be overestimated due to uncontrolled confounding and enhance the literature available for weighing cancer risk from occupational exposure to bitumen.

Human papillomavirus serology and tobacco smoking in a community control group

Background

HPV infection is an established risk factor for oropharyngeal cancer, and it has been proposed that cigarette smoking may potentiate HPV infection in the oral epithelium. We sought to test the hypothesis that cigarette smoking increases HPV infection in an HPV16 serology study of cancer-free individuals.

Methods

Subjects were participants in a risk factor study for head and neck cancer, and were required to have no prior history of either HNSCC or any other cancer. Tobacco use and other risk factor data were gathered through interviewer-assisted questionnaires, while serology was conducted in a blinded fashion using a glutathione S-transferase capture enzyme-linked immunosorbent assay (ELISA) to detect antibodies against HPV16 L1, E1, E2, E4, E6 and E7 proteins. The differences in tobacco use by HPV serology were evaluated by ANOVA; and the reported odds ratios and 95% confidence intervals were determined by using unconditional logistic regression.

Results

We found no overall association of HPV16 serological markers with smoking. However, when the data were stratified by median age, smoking was positively associated with seropositivity for the HPV16 L1 capsid antigen in the younger controls while the older controls were less likely to be HPV16 L1 positive if they smoked (p_interaction < 0.002). There was no similar association of smoking and age with serological response to the early proteins (i.e E6, E7).

Conclusions

Exposure to HPV16 capsid protein (L1) is increased among relatively younger adults who smoke and diminished among older smokers. However, this pattern is not accompanied by a differential susceptibility for active infection (as determined by the early gene proteins such as E6 and E7) among young and older smokers.

Epigenetics of lung cancer

Lung cancer is the leading cause of cancer-related mortality in the United States. Epigenetic alterations, including DNA methylation, histone modifications, and noncoding RNA expression, have been reported widely in the literature to play a major role in the genesis of lung cancer. The goal of this review is to summarize the common epigenetic changes associated with lung cancer to give some clarity to its etiology, and to provide an overview of the potential translational applications of these changes, including applications for early detection, diagnosis, prognostication, and therapeutics.

Abstract 279: Head and neck squamous cell carcinoma risk among asphalt workers from the greater Boston area

Asphalt (or bitumen) is produced from the distillation of crude petroleum and used in road surfacing, roofing, and waterproofing applications. When heated during application, asphalt emits a mixture of fumes, vapors and solid particulates, including carcinogens such as polycyclic aromatic hydrocarbons (PAH), which come in direct contact with the epithelium of the upper aerodigestive tract upon inhalation. Therefore, chronic exposure among asphalt workers could potentially result in elevated risk for upper aerodigestive tract cancers. There are presently no case-control studies reporting on this relationship. There is limited evidence of an association from occupational cohort studies, although these studies offer poor control for important, potentially confounding factors, such as smoking or alcohol consumption. Thus, we have investigated the association between occupational exposure to asphalt and head and neck squamous cell carcinoma (HNSCC) in a large population-based case-control study from the greater Boston area. Occupational asphalt exposure data was available for 951 incident HNSCC cases and 1193 cancer-free control subjects, matched on age (+/- 3 years), sex, and town or neighborhood of residence. Study subjects completed a self-administered questionnaire that provided detailed data on occupational history, sociodemographics and personal characteristics, and alcohol and tobacco use. Asphalt exposure was dichotomized as exposed or never exposed based on self-reported occupation data, and also by total duration of occupational exposure to asphalt. Multivariable unconditional logistic regression was used to assess the association between asphalt exposure and HNSCC, overall and by primary tumor site. A total of 140 (14.7%) cases and 145 (12.2%) controls reported an occupational exposure to asphalt. There was a significant crude association between asphalt exposure and pharyngeal cancer (crude OR = 1.47, 95% CI: 1.09-2.00) and elevated point estimates (although non-significant) for HNSCC overall and in the larynx. However, both the magnitude and significance eroded after adjusting for age, sex, smoking, and alcohol consumption. Similarly, we observed a borderline significant dose-response between occupational duration and crude HNSCC risk, overall and for the pharynx and larynx, but, again, the magnitude and (borderline) significance eroded following adjustment for confounding factors. Since cigarettes are a substantial source of PAH exposure among smokers, we repeated the analysis restricted to never-smokers but did not observe any significant association. We found no evidence for an association between asphalt work and HNSCC risk. These observations suggest that the risk estimates for HNSCC among asphalt workers provided by occupational cohort studies may be overstated due to uncontrolled confounding.

Citation Format: Scott M. Langevin, Melissa Eliot, Michael D. McClean, Karl T. Kelsey. Head and neck squamous cell carcinoma risk among asphalt workers from the greater Boston area. [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 279. doi:10.1158/1538-7445.AM2014-279

Novel DNA methylation targets in oral rinse samples predict survival of patients with oral squamous cell carcinoma

OBJECTIVES

The objective of this study was to identify novel survival-associated biomarkers in oral rinse samples collected from patients with oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

We screened for putative survival-associated markers using publicly available methylation array data from 88 OSCC tumors. Cox models were then fit to methylation array data restricted to these putative loci in oral rinse samples of 82 OSCC patients from greater Boston. Pyrosequencing assays were designed for each locus that replicated in the oral rinse samples and applied to a validation set of oral rinse samples from another 61 OSCC patients.

RESULTS

We identified 7 survival-associated methylation markers in oral rinse samples from OSCC patients, and have validated one, located in the body of GABBR1, by pyrosequencing.

CONCLUSION

The 7 CpG loci identified through this study represent novel prognostic biomarkers for patients with OSCC that can be detected using a non-invasive oral rinse collection technique.