Adam D. Swick

Prevalence of Human Papillomavirus in Oropharyngeal Cancer: A Systematic Review.

PurposeThe global incidence of oropharyngeal squamous cell carcinoma (OPSCC) has been increasing, and it has been proposed that a rising rate of human papillomavirus (HPV)–associated cancers is driving the observed changes in OPSCC incidence. We carried out this systematic review to further examine the prevalence of HPV in OPSCC over time worldwide. MethodsA systematic literature search was performed to identify all articles through January 31, 2014, which reported on the prevalence of HPV in OPSCC. Articles that met the inclusion criteria were divided into 4 time frames (pre-1995, 1995–1999, 2000–2004, and 2005 to present) based on the median year of the study’s sample collection period. Using a weighted analysis of variance model, we examined the trends of HPV-positivity over time worldwide, in North America, and in Europe. ResultsOur literature search identified 699 unique articles. One hundred seventy-five underwent review of the entire study, and 105 met the inclusion criteria. These 105 articles reported on the HPV prevalence in 9541 OPSCC specimens across 23 nations. We demonstrated significant increases in the percentage change of HPV-positive OPSCCs from pre-1995 to present: 20.6% worldwide (P for trend: P < 0.001), 21.6% in North America (P = 0.013), and 21.5% in Europe (P = 0.033). ConclusionsInterestingly, whereas in Europe there was a steady increase in HPV prevalence across all time frames, reaching nearly 50% most recently, in North America HPV prevalence appears to have plateaued over the past decade at about 65%. These findings may have important implications regarding predictions for the future incidence of OPSCC.

Visualizing infection spread: Dual‐color fluorescent reporting of virus–host interactions

Although the molecular mechanisms by which host cells defend themselves against viral infection have been studied in great depth, and countermeasures viruses employ to suppress such defensive responses have been widely documented, relatively little attention has been devoted toward elucidating how such interactions between virus and host are resolved over multiple rounds of infection. Here, we describe the design, synthesis, and validation of a dual‐color fluorescent reporter system to study how viral infections spread through a host cell monolayer and how the cellular innate immune system mounts an antiviral response. We employed recombinant, red fluorescent protein expressing mutants of a prototypical RNA virus, vesicular stomatitis virus to enable identification and tracking of infected cells. Further, we generated stable reporter cells that use green fluorescent protein to report on the expression of IFIT2, an interferon stimulated gene involved in the interference of viral protein translation, and a marker of antiviral defense activation. The presence of the fluorescent protein reporters had minimal effects on the normal behavior of the cells or viruses. Moreover, expression of the virus and cell reporters correlated with the kinetics of viral replication and activation of an anti‐viral response, respectively. This two‐color system enabled us to track and quantify in live cells how viral replication and activation of host defensive responses play out over multiple rounds of infection. Initial study of propagating infections demonstrated that antiviral activation over multiple rounds was critical for slowing and ultimately halting the spread of infection. Biotechnol. Bioeng. 2014;111: 1200–1209.

Tools for Single-Cell Kinetic Analysis of Virus-Host Interactions

Measures of cellular gene expression or behavior, when performed on individual cells, inevitably reveal a diversity of behaviors and outcomes that can correlate with normal or diseased states. For virus infections, the potential diversity of outcomes are pushed to an extreme, where measures of infection reflect features of the specific infecting virus particle, the individual host cell, as well as interactions between viral and cellular components. Single-cell measures, while revealing, still often rely on specialized fluid handling capabilities, employ end-point measures, and remain labor-intensive to perform. To address these limitations, we consider a new microwell-based device that uses simple pipette-based fluid handling to isolate individual cells. Our design allows different experimental conditions to be implemented in a single device, permitting easier and more standardized protocols. Further, we utilize a recently reported dual-color fluorescent reporter system that provides dynamic readouts of viral and cellular gene expression during single-cell infections by vesicular stomatitis virus. In addition, we develop and show how free, open-source software can enable streamlined data management and batch image analysis. Here we validate the integration of the device and software using the reporter system to demonstrate unique single-cell dynamic measures of cellular responses to viral infection.

Pan-HER Inhibitor Augments Radiation Response in Human Lung and Head and Neck Cancer Models

Purpose: Aberrant regulation of the EGF receptor family (EGFR, HER2, HER3, HER4) contributes to tumorigenesis and metastasis in epithelial cancers. Pan-HER represents a novel molecular targeted therapeutic composed of a mixture of six monoclonal antibodies against EGFR, HER2, and HER3. Experimental Design: In the current study, we examine the capacity of Pan-HER to augment radiation response across a series of human lung and head and neck cancers, including EGFR inhibitor–resistant cell lines and xenografts. Results: Pan-HER demonstrates superior antiproliferative and radiosensitizing impact when compared with cetuximab. The mechanisms underlying these effects appear to involve attenuation of DNA damage repair, enhancement of programmed cell death, cell-cycle redistribution, and induction of cellular senescence. Combined treatment of Pan-HER with single or fractionated radiation in human tumor xenografts reveals a potent antitumor and regrowth delay impact compared with Pan-HER or radiation treatment alone. Conclusions: These data highlight the capacity of Pan-HER to augment radiation response in lung and head and neck cancer models and support investigation of Pan-HER combined with radiation as a promising clinical therapeutic strategy. Clin Cancer Res; 22(3); 633–43. ©2015 AACR.

Modulation of therapeutic sensitivity by human papillomavirus.

Human papillomaviruses (HPVs) are small double-stranded DNA viruses that pose significant public health concerns as the causative agent of approximately 5% of worldwide cancers. The HPV oncogenes E6 and E7 play key roles in carcinogenesis. In the last 15years there has been a significant increase in the incidence of HPV-related head and neck cancers arising primarily in the oropharynx. Patients with HPV-positive head and neck cancers (HNCs) have a significantly improved prognosis compared to those with HPV-negative disease. In this review we will discuss data suggesting how HPV oncogenes modulate both the intrinsic radiation sensitivity of HNCs and also have important effects upon the tumor microenvironment. Together, these findings contribute to the improved outcomes seen in patients with HPV-positive HNC.

Xenograft assessment of predictive biomarkers for standard head and neck cancer therapies

Head and neck squamous cell carcinoma (HNSCC) remains a challenging cancer to treat with overall 5‐year survival on the order of 50–60%. Therefore, predictive biomarkers for this disease would be valuable to provide more effective and individualized therapeutic approaches for these patients. While prognostic biomarkers such as p16 expression correlate with outcome; to date, no predictive biomarkers have been clinically validated for HNSCC. We generated xenografts in immunocompromised mice from six established HNSCC cell lines and evaluated response to cisplatin, cetuximab, and radiation. Tissue microarrays were constructed from pre‐ and posttreatment tumor samples derived from each xenograft experiment. Quantitative immunohistochemistry was performed using a semiautomated imaging and analysis platform to determine the relative expression of five potential predictive biomarkers: epidermal growth factor receptor (EGFR), phospho‐EGFR, phospho‐Akt, phospho‐ERK, and excision repair cross‐complementation group 1 (ERCC1). Biomarker levels were compared between xenografts that were sensitive versus resistant to a specific therapy utilizing a two‐sample t‐test with equal standard deviations. Indeed the xenografts displayed heterogeneous responses to each treatment, and we linked a number of baseline biomarker levels to response. This included low ERCC1 being associated with cisplatin sensitivity, low phospho‐Akt correlated with cetuximab sensitivity, and high total EGFR was related to radiation resistance. Overall, we developed a systematic approach to identifying predictive biomarkers and demonstrated several connections between biomarker levels and treatment response. Despite these promising initial results, this work requires additional preclinical validation, likely involving the use of patient‐derived xenografts, prior to moving into the clinical realm for confirmation among patients with HNSCC.

Defining the boundaries and expanding the utility of head and neck cancer patient derived xenografts

BACKGROUND Patient derived xenografts (PDXs) represent an essential tool in oncologic research, and we sought to further expand our repertoire of head and neck squamous cell carcinoma (HNSCC) while determining potential boundaries for this system. METHODS We consented new patients for PDX development and determined if a 24-h time delay from tumor excision to xenograft implantation affected PDX establishment. We developed a tissue microarray (TMA) from formalin fixed, paraffin embedded PDXs and their subsequent passages and carried out quantitative immunohistochemistry for EGFR, pEGFR, pAkt, pERK and ERCC1. First and last passaged PDXs were compared via a paired t-test to examine for the stability of protein expression across passages. We performed a similar comparison of the mutational profile of the patient tumor and resulting xenografts using a targeted sequencing approach. RESULTS No patient/tumor characteristics influenced PDX take rate and the 24-h time delay from tumor excision to xenograft implantation did not affect PDX establishment, growth or histology. There was no significant difference in biomarker expression between the first and last passaged PDXs for EGFR, pEGFR, pAkt, and ERCC1. For pERK there was a significant difference (p=0.002), but further analysis demonstrated this only arose in three of 15 PDXs. Targeted sequencing revealed striking stability of passenger and likely driver mutations from patient to xenograft. CONCLUSIONS The stability of protein expression across PDX passages will hopefully allow greater investigation of predictive biomarkers in order to identify ones for further pre-clinical and clinical investigation.

Rapid induction and persistence of paracrine-induced cellular antiviral states arrest viral infection spread in A549 cells.

The virus/host interaction is a complex interplay between pro- and anti-viral factors that ultimately determines the spread or halt of virus infections in tissues. This interplay develops over multiple rounds of infection. The purpose of this study was to determine how cellular-level processes combine to impact the spatial spread of infection. We measured the kinetics of virus replication (VSV), antiviral paracrine signal upregulation and secretion, spatial spread of virus and paracrine antiviral signaling, and inhibition of virus production in antiviral-exposed A549 human lung epithelial cells. We found that initially infected cells released antiviral signals 4-to-7h following production of virus. However, the subsequent rapid dissemination of signal and fast induction of a robust and persistent antiviral state ultimately led to a suppression of infection spread. This work shows how cellular responses to infection and activation of antiviral responses can integrate to ultimately control infection spread across host cell populations.

Cotargeting mTORC and EGFR Signaling as a Therapeutic Strategy in HNSCC.

Head and neck squamous cell carcinomas (HNSCC) are frequently altered along the PI3K/AKT/mTORC signaling axis. Despite excellent preclinical data, the use of compounds targeting this pathway as monotherapy has been underwhelming in initial clinical trials, and identification of predictive biomarkers remains challenging. To investigate mTORC-specific inhibition, we tested catalytic mTORC (AZD8055) and PI3K/mTORC (NVP-BEZ-235) inhibitors ± cetuximab in a panel of HNSCC cell lines and patient-derived xenografts (PDX). Cell lines were assayed for response to all agents and siRNA knockdown of targets by multiple approaches. All cell lines showed similar response to both drug and siRNA inhibition of both PI3K and mTORC pathways, with anti-EGFR combination producing modest additive effect. Five PDX models that presented PIK3CA mutation or intrinsic cetuximab resistance were treated with a combination of cetuximab and AZD8055. In vivo single-agent mTORC inhibition inhibited growth of one PIK3CA-mutant cancer, but had little effect on any PIK3CAWT or a second PIK3CA-mutant model. In all models, the combination therapy showed greater growth delay than monotherapy. The uniform ability of PI3K and mTORC inhibition to suppress the growth of HNSCC cells highlights the pathways role in driving proliferation. Although single-agent therapy was largely ineffective in vivo, improved response of combination treatment in an array of PDXs suggests the potential for adding a catalytic mTORC inhibitor to cetuximab therapy. Overall, these results add to a growing body of evidence, suggesting that approaches that attempt to match biomarkers to the optimal therapy in HNSCC remain complex and challenging. Mol Cancer Ther; 16(7); 1257–68. ©2017 AACR.

Genome rearrangement affects RNA virus adaptability on prostate cancer cells

Gene order is often highly conserved within taxonomic groups, such that organisms with rearranged genomes tend to be less fit than wild type gene orders, and suggesting natural selection favors genome architectures that maximize fitness. But it is unclear whether rearranged genomes hinder adaptability: capacity to evolutionarily improve in a new environment. Negative-sense non-segmented RNA viruses (order Mononegavirales) have specific genome architecture: 3′ UTR – core protein genes – envelope protein genes – RNA-dependent RNA-polymerase gene – 5′ UTR. To test how genome architecture affects RNA virus evolution, we examined vesicular stomatitis virus (VSV) variants with the nucleocapsid (N) gene moved sequentially downstream in the genome. Because RNA polymerase stuttering in VSV replication causes greater mRNA production in upstream genes, N gene translocation toward the 5′ end leads to stepwise decreases in N transcription, viral replication and progeny production, and also impacts the activation of type 1 interferon mediated antiviral responses. We evolved VSV gene-order variants in two prostate cancer cell lines: LNCap cells deficient in innate immune response to viral infection, and PC-3 cells that mount an IFN stimulated anti-viral response to infection. We observed that gene order affects phenotypic adaptability (reproductive growth; viral suppression of immune function), especially on PC-3 cells that strongly select against virus infection. Overall, populations derived from the least-fit ancestor (most-altered N position architecture) adapted fastest, consistent with theory predicting populations with low initial fitness should improve faster in evolutionary time. Also, we observed correlated responses to selection, where viruses improved across both hosts, rather than suffer fitness trade-offs on unselected hosts. Whole genomics revealed multiple mutations in evolved variants, some of which were conserved across selective environments for a given gene order.