Vaccination with a nanoparticle E7 vaccine can prevent tumor recurrence following surgery in a human papillomavirus head and neck cancer model.

High-risk human papillomavirus (HPV) encoding E6/E7-HPV oncogenes are responsible for a subgroup of head and neck squamous-cell carcinoma (HNSCC) and thus therapeutic E7-vaccines may be used to control HPV+HNSCC tumors. Herein we investigated the effects of an optimized nanoparticle-conjugated E7 long-peptide vaccine adjuvanted with CpG (NP-E7LP) in an orthotopic immunocompetent mouse model of HPV+HNSCC which is based on injection of HPV16 E6/E7-expressing mEERL95-cells into the submental space. In absence of surgery, vaccination performed before or after tumor-cell injection decreased tumor growth or prolonged mice survival only marginally, despite the high numbers of vaccine-induced circulating E7-specific IFN-γ-secreting CD8+ T-cells. This contrasts with the high-efficacy of NP-E7LP-vaccination reported in the genital and subcutaneous HPV16-E6/E7-expressing TC-1 models. Our data show that in a direct comparison, NP-E7LP-vaccination fully controlled TC-1, but not mEERL95, tumors subcutaneously growing in the flanks. Immune-cell infiltration was 10-fold higher in TC-1-tumors, than in mEERL95-tumors, suggesting that vaccine-induced CD8+ T-cells can only poorly infiltrate mEERL95-tumors. Indeed, immunofluorescence staining of orthotopic mEERL95-tumors showed that CD3+ T-cells are preferentially located peritumorally. However, when NP-E7LP-vaccination was performed after mEERL95-cell injection, but before resection of primary tumors, no postsurgical recurrence was observed and 100% of the mice survived until the experimental endpoint (day 70) in the NP-E7LP-vaccinated group. In contrast, we observed a 60% recurrence rate and only 35% survival in PBS-vaccinated mice. This suggests that removal of the primary tumor modified the tumor microenvironment, allowing a therapeutic effect of the vaccine-induced anti-tumor response. E7-vaccination combined with surgery may thus benefit patients with HPV+HNSCC.

CD40 Agonist Targeted to Fibroblast Activation Protein α Synergizes with Radiotherapy in Murine HPV-Positive Head and Neck Tumors.

PURPOSE: The incidence of human papillomavirus-associated head and neck squamous cell carcinoma (HPV+-HNSCC) is rising worldwide and although current therapeutic modalities are efficient in the majority of patients, there is a high rate of treatment failures. Thus, novel combination approaches are urgently needed to achieve better disease control in patients with HPV+-HNSCC. We investigated the safety and therapeutic efficacy of a novel fibroblast activation protein (FAP)-targeted CD40 agonist (FAP-CD40) in combination with local hypofractionated radiation in a syngeneic HPV+-HNSCC model. EXPERIMENTAL DESIGN: Using an established orthotopic model, we treated tumor-bearing mice with local hypofractionated radiotherapy (2 × 6 Gy) alone or in combination with a systemic administration of the FAP-CD40 antibody. Following up the mice, we evaluated the changes in the tumor microenvironment (TME) by immunofluorescence, FACS, and NanoString RNA analysis. RESULTS: The suboptimal radiotherapy regimen chosen failed to control tumors in the treated mice. The FAP-CD40 administered in monotherapy transiently controlled tumor growth, whereas the combined therapy induced durable complete responses in more than 80% of the tumor-bearing mice. This notable efficacy relied on the radiotherapy-induced remodeling of the TME and activation of the CD8+ T-cell-cDC1 axis and was devoid of the systemic toxicity frequently associated with CD40-targeted therapy. Moreover, the robust immunologic memory developed effectively prevented tumor relapses, a common feature in patients with HNSCC. CONCLUSIONS: Our study provides proof of concept, as well as mechanistic insights of the therapeutic efficacy of a bispecific FAP-CD40 combined with local radiotherapy in a FAP+-HNSCC model increasing overall survival and inducing long-term antitumor immunity.

The transcription factor FOXM1 regulates the balance between proliferation and aberrant differentiation in head and neck squamous cell carcinoma.

Sustained expression of FOXM1 is a hallmark of nearly all human cancers including squamous cell carcinomas of the head and neck (HNSCC). HNSCCs partially preserve the epithelial differentiation program, which recapitulates fetal and adult traits of the tissue of tumor origin but is deregulated by genetic alterations and tumor-supporting pathways. Using shRNA-mediated knockdown, we demonstrate a minimal impact of FOXM1 on proliferation and migration of HNSCC cell lines under standard cell culture conditions. However, FOXM1 knockdown in three-dimensional (3D) culture and xenograft tumor models resulted in reduced proliferation, decreased invasion, and a more differentiated-like phenotype, indicating a context-dependent modulation of FOXM1 activity in HNSCC cells. By ectopic overexpression of FOXM1 in HNSCC cell lines, we demonstrate a reduced expression of cutaneous-type keratin K1 and involucrin as a marker of squamous differentiation, supporting the role of FOXM1 in modulation of aberrant differentiation in HNSCC. Thus, our data provide a strong rationale for targeting FOXM1 in HNSCC. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Cellular Barcoding Identifies Clonal Substitution as a Hallmark of Local Recurrence in a Surgical Model of Head and Neck Squamous Cell Carcinoma.

Local recurrence after surgery for head and neck squamous cell carcinoma (HNSCC) remains a common event associated with a dismal prognosis. Improving this outcome requires a better understanding of cancer cell populations that expand from postsurgical minimal residual disease (MRD). Therefore, we assessed clonal dynamics in a surgical model of barcoded HNSCC growing in the submental region of immunodeficient mice. Clonal substitution and massive reduction of clonal heterogeneity emerged as hallmarks of local recurrence, as the clones dominating in less heterogeneous recurrences were scarce in their matched primary tumors. These lineages were selected by their ability to persist after surgery and competitively expand from MRD. Clones enriched in recurrences exhibited both private and shared genetic features and likely originated from ancestors shared with clones dominating in primary tumors. They demonstrated high invasiveness and epithelial-to-mesenchymal transition, eventually providing an attractive target for obtaining better local control for these tumors.

Mouse model of postsurgical primary tumor recurrence and regional lymph node metastasis progression in HPV-related head and neck cancer.

HPV-positive head and neck squamous cell carcinoma (HNSCC) is increasingly frequent. Management is particularly debated in the case of postsurgical high-risk features, that is, positive surgical margins and extracapsular spread (ECS). In this increasingly complex emerging framework of HNSCC treatment, representative preclinical models are needed to support future clinical trials and advances in personalized medicine. Here, we present an immunocompetent mouse model based on the implantation of mouse tonsil epithelial HPV16-E6/E7-expressing cancer cells into the submental region of the floor-of-the-mouth. Primary tumors were found to replicate the patterns of human HNSCC local invasion and lymphatic dissemination. To study disease progression after surgery, tumors were removed likely leaving behind residual disease. Surgical resection of tumors was followed by a high rate of local recurrences (>90%) within the first 2-3 weeks. While only 50% of mice had lymph node metastases (LNM) at time of primary tumor excision, all mice with recurrent tumors showed evidence of LNM. To study the consecutive steps of LNM progression and distant metastasis development, LNs from tumor-bearing mice were transplanted into naïve recipient mice. Using this approach, transplanted LNs were found to recapitulate all stages and relevant histological features of regional metastasis progression, including ECS and metastatic spread to the lungs. Altogether, we have developed an immunocompetent HPV-positive HNSCC mouse model of postsurgical local recurrence and regional and distant metastasis progression suitable for preclinical studies.

A natural ligand for the orphan receptor GPR15 modulates lymphocyte recruitment to epithelia.

GPR15 is an orphan G protein-coupled receptor (GPCR) that is found in lymphocytes. It functions as a co-receptor of simian immunodeficiency virus and HIV-2 and plays a role in the trafficking of T cells to the lamina propria in the colon and to the skin. We describe the purification from porcine colonic tissue extracts of an agonistic ligand for GPR15 and its functional characterization. In humans, this ligand, which we named GPR15L, is encoded by the gene C10ORF99 and has some features similar to the CC family of chemokines. GPR15L was found in some human and mouse epithelia exposed to the environment, such as the colon and skin. In humans, GPR15L was also abundant in the cervix. In skin, GPR15L was readily detected after immunologic challenge and in human disease, for example, in psoriatic lesions. Allotransplantation of skin from Gpr15l-deficient mice onto wild-type mice resulted in substantial graft protection, suggesting nonredundant roles for GPR15 and GPR15L in the generation of effector T cell responses. Together, these data identify a receptor-ligand pair that is required for immune homeostasis at epithelia and whose modulation may represent an alternative approach to treating conditions affecting the skin such as psoriasis.

Piezoresistive Membrane Surface Stress Sensors for Characterization of Breath Samples of Head and Neck Cancer Patients.

For many diseases, where a particular organ is affected, chemical by-products can be found in the patient's exhaled breath. Breath analysis is often done using gas chromatography and mass spectrometry, but interpretation of results is difficult and time-consuming. We performed characterization of patients' exhaled breath samples by an electronic nose technique based on an array of nanomechanical membrane sensors. Each membrane is coated with a different thin polymer layer. By pumping the exhaled breath into a measurement chamber, volatile organic compounds present in patients' breath diffuse into the polymer layers and deform the membranes by changes in surface stress. The bending of the membranes is measured piezoresistively and the signals are converted into voltages. The sensor deflection pattern allows one to characterize the condition of the patient. In a clinical pilot study, we investigated breath samples from head and neck cancer patients and healthy control persons. Evaluation using principal component analysis (PCA) allowed a clear distinction between the two groups. As head and neck cancer can be completely removed by surgery, the breath of cured patients was investigated after surgery again and the results were similar to those of the healthy control group, indicating that surgery was successful.

Negative control of keratinocyte differentiation by Rho/CRIK signaling coupled with up-regulation of KyoT1/2 (FHL1) expression.

Rho GTPases integrate control of cell structure and adhesion with downstream signaling events. In keratinocytes, RhoA is activated at early times of differentiation and plays an essential function in establishment of cell-cell adhesion. We report here that, surprisingly, Rho signaling suppresses downstream gene expression events associated with differentiation. Similar inhibitory effects are exerted by a specific Rho effector, CRIK (Citron kinase), which is selectively down-modulated with differentiation, thereby allowing the normal process to occur. The suppressing function of Rho/CRIK on differentiation is associated with induction of KyoT1/2, a LIM domain protein gene implicated in integrin-mediated processes and/or Notch signaling. Like activated Rho and CRIK, elevated KyoT1/2 expression suppresses differentiation. Thus, Rho signaling exerts an unexpectedly complex role in keratinocyte differentiation, which is coupled with induction of KyoT1/2, a LIM domain protein gene with a potentially important role in control of cell self renewal.