Transcriptomic and epigenetic landscape of nimorazole-enhanced radiochemotherapy in head and neck cancer.

BACKGROUND: Hypoxia remains a challenge for the therapeutic management of head and neck squamous cell carcinoma (HNSCC). The combination of radiotherapy with nimorazole has shown treatment benefit in HNSCC, but the precise underlying molecular mechanisms remain unclear. PURPOSE: To assess and to characterize the transcriptomic/epigenetic landscape of HNSCC tumor models showing differential therapeutic response to fractionated radiochemotherapy (RCTx) combined with nimorazole. MATERIALS/METHODS: Bulk RNA-sequencing and DNA methylation experiments were conducted using untreated and treated HNSCC xenografts after 10 fractions of RCTx with and without nimorazole. These tumor models (FaDu, SAS, Cal33, SAT and UT-SCC-45) previously showed a heterogeneous response to RCTx with nimorazole. The prognostic impact of candidate genes was assessed using clinical and gene expression data from HNSCC patients treated with primary RCTx within the DKTK-ROG. RESULTS: Nimorazole responder and non-responder tumor models showed no differences in hypoxia gene signatures However, non-responder models showed upregulation of metabolic pathways. From that, a subset of 15 differentially expressed genes stratified HNSCC patients into low and high-risk groups with distinct outcome. CONCLUSION: In the present study, we found that nimorazole non-responder models were characterized by upregulation of genes involved in Retinol metabolism and xenobiotic metabolic process pathways, which might contribute to identify mechanisms of resistance to nitroimidazole compounds and potentially expand the repertoire of therapeutic options to treat HNSCC.

Immune cell infiltration in head and neck squamous cell carcinoma and patient outcome: a retrospective study.

BACKGROUND: Human papillomavirus (HPV) prevalence in oropharynx squamous cell carcinoma (OPSCC) is on the rise. HPV-linked OPSCCs represent a distinct clinical entity with a better treatment response and patient survival compared to tumors not linked to HPV. An emerging role in treatment response has been attributed to immune cell infiltration in human tumors. In this study, we investigated immune cell infiltration in human SCC of the head and neck region and its relation to overall survival after treatment with surgery (with or without radiotherapy) or concomitant chemo (or cetuximab)-radiotherapy. MATERIALS AND METHODS: Paraffin-embedded tumor samples of 136 patients with SCC of the larynx, hypopharynx, oral cavity and oropharynx were processed for immunohistochemical detection of CD3+ T-cells, CD8+ cytotoxic T-cells, CD20+ B-cells and CD163+ M2 macrophages within the tumor infiltrated area. Clinico-pathological data were analyzed as a function of tumor location and p16-status. Immune cell infiltration was represented as stained area on the whole tumor infiltrated area, compared for the different tumor locations and correlated to patient survival. RESULTS: Patients with oropharynx tumors expressing significant p16 levels (p16-sg) had a 5-year overall survival of 85% compared to 43% for patients with no significant p16 (p16-ns) expression (HR: 0.3 - 95% CI: 0.1-0.6). Median immune cell infiltration (T- and B-lymphocytes) was significantly elevated in p16-sg oropharyngeal tumors, compared to p16-ns oropharyngeal tumors and to all other head and neck tumor locations. No difference in CD163+ macrophage infiltration was observed across the different patient groups. In the whole population, a high infiltration by CD3+ T-lymphocytes was associated to a significantly (p = .03; HR: 0.6, 95% CI: 0.4-0.97) better overall survival. CONCLUSION: Oropharynx cancer with significant p16 expression showed an increased overall survival and elevated T- and B-lymphocyte infiltration, which suggests a prognostic relevance of immune cell infiltration.

Lack of differences in radiation-induced immunogenicity parameters between HPV-positive and HPV-negative human HNSCC cell lines.

BACKGROUND AND PURPOSE: Clinical studies indicate that patients with HPV/p16-associated head & neck squamous cell carcinoma (HNSCC) represent a subgroup with a better prognosis and improved response to conventional radiotherapy. Involvement of immune-based factors has been hypothesized. In the present study, we investigated radiation-induced differences in release of damage associated molecular patterns (DAMPs), cytokines and activation of dendritic cells (DCs) in HPV-positive and negative HNSCC cancer cell lines. MATERIAL AND METHODS: Calreticulin (CRT) exposure was detected on cancer cell surface. ATP, HMGB1 and cytokines were measured in culture supernatants. Maturation marker CD83 surface exposure was determined on DCs after co-incubation with irradiated tumor cells. RESULTS: There was no increase in DAMPs and cytokine profiles after radiation treatment and no difference between HPV+ and HPV- cell lines. The HPV/p16-positive SCC90 cells showed a trend for increased total CRT, HMGB1, and number of cytokines compared to all other cell lines. None of the irradiated cancer cell lines could affect DC maturation. CONCLUSIONS: Radiation treatment did not increase immunogenicity of HNSCC cell lines assessed by membrane CRT, ATP, HMGB1, cytokines production, and by activation of immature DCs. There was no difference between HPV-positive and HPV-negative cell lines.