Alterations in the p53 pathway and their association with radio- and chemosensitivity in head and neck squamous cell carcinoma

High-risk TP53 mutations predict poor primary treatment response of patients with head and neck squamous cell carcinoma

OBJECTIVES

Head and neck squamous cell carcinoma (HNSCC) poses a diagnostic and therapeutic challenge worldwide and is associated with a poor survival rate. Due to the variability in the efficacy of treatments for HNSCC, new predictive biomarkers of therapy outcomes are needed. Recently, we developed an algorithm that employs the mutational profile of TP53 as an independent prognostic factor in HNSCC. In this study, we investigated its role as a predictive biomarker of treatment outcomes in HNSCC patients. We also tested the usefulness of two classification systems for TP53 mutational landscapes.

MATERIALS AND METHODS

Clinical and genomic data were retrieved from The Cancer Genome Atlas database. We built a multivariate stepwise backward binary regression model to assess the role of TP53 mutations in predicting therapeutic outcomes.

RESULTS

Cases harbouring high-risk-of-death mutations reported an odds ratio of 3.301 for stable or progressive disease compared to wild-type cases, while no significant difference in treatment outcomes was found between cases with low-risk-of-death mutations and wild-type TP53. Our analysis found that older patients with a history of alcohol consumption had a higher risk of stable/progressive disease.

CONCLUSIONS

This study improves current evidence on the role of TP53 mutations in treatment response in HNSCC patients.

Preclinical Models of Laryngeal Papillomavirus Infection: A Scoping Review

OBJECTIVE

Laryngeal human papillomavirus (HPV) infection causes recurrent respiratory papillomatosis (RRP) and accounts for up to 25% of laryngeal cancers. Lack of satisfactory preclinical models is one reason that treatments for these diseases are limited. We sought to assess the literature describing preclinical models of laryngeal papillomavirus infection.

DATA SOURCES

PubMed, Web of Science, and Scopus were searched from the inception of database through October 2022.

REVIEW METHODS

Studies searched were screened by two investigators. Eligible studies were peer-reviewed, published in English, presented original data, and described attempted models of laryngeal papillomavirus infection. Data examined included type of papillomavirus, infection model, and results including success rate, disease phenotype, and viral retention.

RESULTS

After screening 440 citations and 138 full-text studies, 77 studies published between 1923 and 2022 were included. Models used low-risk HPV or RRP (n = 51 studies), high-risk HPV or laryngeal cancer (n = 16), both low- and high-risk HPV (n = 1), and animal papillomaviruses (n = 9). For RRP, 2D and 3D cell culture models and xenografts retained disease phenotypes and HPV DNA in the short term. Two laryngeal cancer cell lines were consistently HPV-positive in multiple studies. Animal laryngeal infections with animal papillomaviruses resulted in disease and long-term retention of viral DNA.

CONCLUSIONS

Laryngeal papillomavirus infection models have been researched for 100 years and primarily involve low-risk HPV. Most models lose viral DNA after a short duration. Future work is needed to model persistent and recurrent diseases, consistent with RRP and HPV-positive laryngeal cancer.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:3256-3268, 2023.

Clinical Trial Development in TP53-Mutated Locally Advanced and Recurrent and/or Metastatic Head and Neck Squamous Cell Carcinoma

TP53 mutation is the most frequent genetic event in head and neck squamous cell carcinoma (HNSCC), found in more than 80% of patients with human papillomavirus-negative disease. As mutations in the TP53 gene are associated with worse outcomes in HNSCC, novel therapeutic approaches are needed for patients with TP53-mutated tumors. The National Cancer Institute sponsored a Clinical Trials Planning Meeting to address the issues of identifying and developing clinical trials for patients with TP53 mutations. Subcommittees, or breakout groups, were tasked with developing clinical studies in both the locally advanced and recurrent and/or metastatic (R/M) disease settings as well as considering signal-seeking trial designs. A fourth breakout group was focused on identifying and standardizing biomarker integration into trial design; this information was provided to the other breakout groups prior to the meeting to aid in study development. A total of 4 concepts were prioritized to move forward for further development and implementation. This article summarizes the proceedings of the Clinical Trials Planning Meeting with the goal of developing clinical trials for patients with TP53-mutant HNSCC that can be conducted within the National Clinical Trials Network.

Restoring p53 Function in Head and Neck Squamous Cell Carcinoma to Improve Treatments

TP53 mutation is one of the most frequent genetic alterations in head and neck squamous cell carcinoma (HNSCC) and results in an accumulation of p53 protein in tumor cells. This makes p53 an attractive target to improve HNSCC therapy by restoring the tumor suppressor activity of this protein. Therapeutic strategies targeting p53 in HNSCC can be divided into three categories related to three subtypes encompassing WT p53, mutated p53 and HPV-positive HNSCC. First, compounds targeting degradation or direct inhibition of WT p53, such as PM2, RITA, nutlin-3 and CH1iB, achieve p53 reactivation by affecting p53 inhibitors such as MDM2 and MDMX/4 or by preventing the breakdown of p53 by inhibiting the proteasomal complex. Second, compounds that directly affect mutated p53 by binding it and restoring the WT conformation and transcriptional activity (PRIMA-1, APR-246, COTI-2, CP-31398). Third, treatments that specifically affect HPV+ cancer cells by targeting the viral enzymes E6/E7 which are responsible for the breakdown of p53 such as Ad-E6/E7-As and bortezomib. In this review, we describe and discuss p53 regulation and its targeting in combination with existing therapies for HNSCC through a new classification of such cancers based on p53 mutation status and HPV infection.

[Tumor biology of oropharyngeal carcinoma]

BACKGROUND

Etiologically, oropharyngeal squamous cell carcinoma (OPSCC) can be divided into OPSCC caused by noxious agents and human papillomavirus (HPV)-driven carcinoma. These types differ with regard to clinical features and prognosis-differences which are rooted in the underlying molecular biology of the tumor.

OBJECTIVE

The aim of this work is to provide an overview of the molecular biological characteristics of the genetics, epigenetics, and immunology of OPSCC.

MATERIALS AND METHODS

A literature review was performed on a selection of genetic, epigenetic, and immunological factors characterizing OPSCC.

RESULTS

The understanding of genetic aberrations and their consequences for cancerogenesis and tumor biology is increasing. Epigenetic phenomena are complementing functional relationships. However, epigenetic mechanisms of gene regulation are complex and much research is still required in this field. Immunological aspects of cancer molecular biology have moved into the focus in light of recent advances in the field of immunotherapy.

CONCLUSION

The tumor biology of OPSCC is primarily defined by its HPV status. Additionally, HPV-independent genetic, epigenetic, and immunological signatures are being defined. From these advances, rationales for new treatment concepts may evolve.

Upregulation of the long non-coding RNA CASC9 as a biomarker for squamous cell carcinoma

BACKGROUND

Few diagnostic and prognostic biomarkers are available for head-and-neck squamous cell carcinoma (HNSCC). Long non-coding RNAs (lncRNAs) have shown promise as biomarkers in other cancer types and in some cases functionally contribute to tumor development and progression. Here, we searched for lncRNAs useful as biomarkers in HNSCC.

METHODS

Public datasets were mined for lncRNA candidates. Two independent HNSCC tissue sets and a bladder cancer tissue set were analyzed by RT-qPCR. Effects of lncRNA overexpression or downregulation on cell proliferation, clonogenicity, migration and chemosensitivity were studied in HNSCC cell lines.

RESULTS

Data mining revealed prominently CASC9, a lncRNA significantly overexpressed in HNSCC tumor tissues according to the TCGA RNAseq data. Overexpression was confirmed by RT-qPCR analyses of patient tissues from two independent cohorts. CASC9 expression discriminated tumors from normal tissues with even higher specificity than HOTAIR, a lncRNA previously suggested as an HNSCC biomarker. Specificity of HNSCC detection by CASC9 was further improved by combination with HOTAIR. Analysis of TCGA pan-cancer data revealed significant overexpression of CASC9 across different other entities including bladder, liver, lung and stomach cancers and especially in squamous cell carcinoma (SCC) of the lung. By RT-qPCR analysis we furthermore detected stronger CASC9 overexpression in pure SCC of the urinary bladder and mixed urothelial carcinoma with squamous differentiation than in pure urothelial carcinomas. Thus, CASC9 might represent a general diagnostic biomarker and particularly for SCCs. Unexpectedly, up- or downregulation of CASC9 expression in HNSCC cell lines with low or high CASC9 expression, respectively, did not result in significant changes of cell viability, clonogenicity, migration or chemosensitivity.

CONCLUSIONS

CASC9 is a promising biomarker for HNSCC detection. While regularly overexpressed, however, this lncRNA does not seem to act as a major driver of development or progression in this tumor.

PYHIN genes as potential biomarkers for prognosis of human papillomavirus-positive or -negative head and neck squamous cell carcinomas

The aim of the present study is to determine the expression levels of PYHIN (IFI16 and AIM2) and APOBEC3 (A3A, A3B, A3C, A3D, A3F, A3G, and A3H) gene family members in a cohort of patients with head and neck squamous cell carcinoma (HNSCC) and assess their potential correlation with human papillomavirus (HPV) infection status, clinical characteristics, and survival. For this purpose, 34 HNSCC tissue specimens along with healthy surrounding mucosa were collected from patients surgically treated for HNSCC. Nucleic acids were isolated to assess the presence of HPV and the expression levels of selected molecular markers. Survival analysis was carried out using the Kaplan-Meier method. In HPV-negative (HPV-) HNSCCs, we detected low mRNA expression levels of IFI16, A3A, and A3B, whereas these genes were upregulated of 2-100 folds in HPV-positive (HPV+) tumors (p < 0.05). Interestingly, AIM2 gene expression levels were predominantly unchanged in HPV+ HNSCCs compared to their HPV- counterparts, in which AIM2 was predominantly upregulated (10% vs. 50% of patients). In HPV- tumors, upregulation of TP53, NOTCH1, PD-L1, and IFI16 correlated with lower occurrence of nodal metastases. On the other hand, the expression of APOBEC family members did not correlate with clinical characteristics. Regarding survival, patients with upregulated A3F gene expression had a worse prognosis, while patients without changes in A3H expression had a lower survival rate. In conclusion, our findings indicate that the innate immune sensors IFI16 and AIM2 and some APOBEC family members could be potentially used as biomarkers for disease outcome in HNSCC patients regardless of HPV presence.

Circadian (De)regulation in Head and Neck Squamous Cell Carcinoma

Head and neck cancer encompass different malignancies that develop in and around the throat, larynx, nose, sinuses and mouth. Most head and neck cancers are squamous cell carcinomas (HNSCC) that arise in the flat squamous cells that makeup the thin layer of tissue on the surface of anatomical structures in the head and neck. Each year, HNSCC is diagnosed in more than 600,000 people worldwide, with about 50,000 new cases. HNSCC is considered extremely curable if detected early. But the problem remains in treatment of inoperable cases, residues or late stages. Circadian rhythm regulation has a big role in developing various carcinomas, and head and neck tumors are no exception. A number of studies have reported that alteration in clock gene expression is associated with several cancers, including HNSCC. Analyses on circadian clock genes and their association with HNSCC have shown that expression of PER1, PER2, PER3, CRY1, CRY2,CKIε, TIM, and BMAL1 are deregulated in HNSCC tissues. This review paper comprehensively presents data on deregulation of circadian genes in HNSCC and critically evaluates their potential diagnostics and prognostics role in this type of pathology.

DDB2 regulates Epithelial-to-Mesenchymal Transition (EMT) in Oral/Head and Neck Squamous Cell Carcinoma

DDB2 is a sensor of DNA damage and it plays an important role in Global Genomic Repair (GG-NER). Our previous studies show that DDB2 is involved in the regulation of metastasis in colon adenocarcinoma. Squamous Cell Carcinomas in the Oral/Head & Neck region (HNSCC) are particularly aggressive due to high incidence of recurrence and distant metastasis. In this study, we show that DDB2 expression is downregulated in advanced HNSCCs and loss of DDB2 expression coincides with reduced survival. Recent meta-analysis of gene expression data characterized the mesenchymal-type (EMT-type) as one most aggressive cancer cluster in HNSCC. Here, we report that DDB2 constitutively represses mRNA expression of the EMT- regulatory transcription factors SNAIL, ZEB1, and angiogenic factor VEGF in HNSCC cells. As a result, re-expression of DDB2 in metastatic cells reversed EMT with transcriptional upregulation of epithelial marker E-cadherin, and downregulation of mesenchymal markers N-cadherin, Vimentin, and Fibronectin. Interestingly, in a reverse assay, depletion of DDB2 in non-metastatic cells induced expression of the same EMT-regulatory transcription factors. TGFβs are major regulators of Snail and Zeb1, and we observed that DDB2 transcriptionally regulates expression of TGFB2 in HNSCC cells. Re-expression of DDB2 in mouse embryonic fibroblasts (MEFs) isolated from Ddb2 (-/-) knockout-mice resulted in repression of EMT-regulatory factors Zeb1, Snail and Tgfb2. Taken together, these results support the active role of DDB2 as a candidate suppressor of the EMT-process in HNSCC. Early detection leads to significantly higher survival in HNSCC and DDB2 expression in tumors can be a predictor of EMT progression.

Methyl-donor depletion of head and neck cancer cells in vitro establishes a less aggressive tumour cell phenotype

PURPOSE

DNA methylation plays a fundamental role in the epigenetic control of carcinogenesis and is, in part, influenced by the availability of methyl donors obtained from the diet. In this study, we developed an in-vitro model to investigate whether methyl donor depletion affects the phenotype and gene expression in head and neck squamous cell carcinoma (HNSCC) cells.

METHODS

HNSCC cell lines (UD-SCC2 and UPCI-SCC72) were cultured in medium deficient in methionine, folate, and choline or methyl donor complete medium. Cell doubling-time, proliferation, migration, and apoptosis were analysed. The effects of methyl donor depletion on enzymes controlling DNA methylation and the pro-apoptotic factors death-associated protein kinase-1 (DAPK1) and p53 upregulated modulator of apoptosis (PUMA) were examined by quantitative-PCR or immunoblotting.

RESULTS

HNSCC cells cultured in methyl donor deplete conditions showed significantly increased cell doubling times, reduced cell proliferation, impaired cell migration, and a dose-dependent increase in apoptosis when compared to cells cultured in complete medium. Methyl donor depletion significantly increased the gene expression of DNMT3a and TET-1, an effect that was reversed upon methyl donor repletion in UD-SCC2 cells. In addition, expression of DAPK1 and PUMA was increased in UD-SCC2 cells cultured in methyl donor deplete compared to complete medium, possibly explaining the observed increase in apoptosis in these cells.

CONCLUSION

Taken together, these data show that depleting HNSCC cells of methyl donors reduces the growth and mobility of HNSCC cells, while increasing rates of apoptosis, suggesting that a methyl donor depleted diet may significantly affect the growth of established HNSCC.

The role of human papillomavirus on the prognosis and treatment of oropharyngeal carcinoma

Human papillomavirus positive oropharyngeal cancer (HPV-positive OPC) is a distinct subtype of head and neck carcinoma (HNC) distinguished from HPV-negative HNC by its risk factor profile, clinical behavior, and molecular biology. Compared to HPV-negative HNC, HPV-positive OPC exhibits significantly better prognosis and an enhanced response to treatment. Recognition of the survival benefit of HPV-positive tumors has led to therapeutic de-intensification strategies aiming to mitigate treatment-related toxicities while maintaining high response rates. In this review, we summarize key aspects of oral HPV infection and the molecular mechanisms of HPV-related carcinogenesis. We review the clinical and molecular characteristics of HPV-positive OPC that contribute to its improved prognosis compared to HPV-negative HNC. We also discuss current and emerging treatment strategies, emphasizing potential mechanisms of treatment sensitivity and the role of therapeutic de-intensification in HPV-positive OPC. Lastly, we examine literature on the management and prognosis of recurrent/metastatic HPV-positive OPC with a focus on the role of salvage surgery in its management.

What is the role of postoperative re-irradiation in recurrent and second primary squamous cell cancer of head and neck? A literature review according to PICO criteria

Re-irradiation has been increasingly offered as a potential effective treatment for head and neck squamous cell carcinoma (HNSCC) loco-regional recurrence as well as second primary tumor in previously irradiated area. This review focused on the role of postoperative re-irradiation (POreRT) in terms of feasibility, toxicity and long-term outcomes in HNSCC patients. The key issue for the research was formulated in two questions according to the PICO (population, intervention, control, and outcomes) criteria. A total of 16 publications met the inclusion criteria for a total of 919 patients; in 522 patients POreRT was performed. POreRT in recurrent and second primary HNSCC seems to be feasible in highly selected patients with the intent to guarantee an acceptable LC compared to surgery alone. The optimal RT schedule remains unclear due to the heterogeneity of literature data.

Overcoming radioresistance in head and neck squamous cell carcinoma

Radiation therapy plays an essential role in the treatment of head and neck squamous cell carcinoma (HNSCC), yet therapeutic efficacy is hindered by treatment-associated toxicity and tumor recurrence. In comparison to other cancers, innovation has proved challenging, with the epidermal growth factor receptor (EGFR) antibody cetuximab being the only new radiosensitizing agent approved by the FDA in over half a century. This review examines the physiological mechanisms that contribute to radioresistance in HNSCC as well as preclinical and clinical data regarding novel radiosensitizing agents, with an emphasis on those with highest translational promise.

PITX1 is a novel predictor of the response to chemotherapy in head and neck squamous cell carcinoma

The pituitary homeobox 1 (PITX1) protein is essential for developmental processes in humans. Previously, PITX1 was identified as a possible tumor suppressor gene in various types of human carcinoma. However, the association between PITX1 and human head and neck squamous cell carcinoma (HNSCC) remains to be elucidated. Immunohistochemical analysis was performed to examine the expression levels of PITX1 in 47 cases of HNSCC, and in 4 control cases. The expression of p53 was also examined in these cases. The labeling indices (LIs) were calculated, and the correlations between clinical factors (chemosensitivity, prognosis and the degree of differentiation) and the LIs were assessed. The PITX1 LI in HNSCC was 27.4±14.5%, which was significantly lower compared with the LIs of the control samples: 76.9±6.97% (P<0.05). Additionally, the PITX1 LIs were 39.9±6.2, 26.9±16.9 and 24.2±11.8% in the complete response (CR), partial response (PR), stable disease or progressive disease (SD/PD) groups, respectively. The PITX1 LI in the CR group revealed the highest result between the all groups, and it was significantly greater compared with that in the SD/PD group (P<0.01). The p53 LIs were 24.5±19.9, 25.7±16.9 and 19.8±13.8 in the CR, PR and SD/PD groups, respectively (P>0.05). Neither the PITX1 nor the p53 LIs were a statistically significant indicator of the prognosis. PITX1 is a candidate tumor suppressor gene and a possible predictive biomarker of chemosensitivity of human HNSCC.

[Immunomodulation as innovative therapy for head and neck tumors : Current developments]

Head and neck squamous cell carcinoma (HNSCC) is characterized by its intense immune suppression and its elaborate immune escape mechanisms. Due to the fact that survival rates remain low, the role of immunotherapy has become more important and the focus of current clinical studies has shifted toward antibody-based immune checkpoint modulation. Application of immunotherapy in curative settings or for prevention of recurrent disease would be desirable.

Targeting irradiation-induced mitogen-activated protein kinase activation in vitro and in an ex vivo model for human head and neck cancer

BACKGROUND

Despite new radiotherapeutic strategies, radioresistance in head and neck squamous cell carcinoma (HNSCC) remains a major problem. Preclinical model systems are needed to identify resistance mechanisms in this heterogeneous entity.

METHODS

We elucidated the interplay among mitogen-activated protein kinase (MAPK)-inhibition, radiation, and p53 mutations in vitro and in a novel ex vivo model derived from vital human HNSCC samples. HNSCC cell lines (p53WT/mut) were treated with the mitogen-activated protein kinase (MEK)-inhibitor PD-0325901 and subsequently irradiated. Radiosensitization was functionally assessed and evaluated in the ex vivo model.

RESULTS

We observed a pronounced irradiation-induced extracellular signal-regulated kinase (ERK) phosphorylation in 2 cell lines, which was independent of their p53 mutation status and associated with PD-0325901-related radiosensitization in a clonogenic assay. Heterogeneity in irradiation-induced ERK phosphorylation and in radiosensitization after MEK-inhibition was also reflected in the ex vivo model.

CONCLUSION

We provide experimental evidence for radiosensitizing effects of PD-0325901 in HNSCC. The ex vivo culture technology might offer a promising tool for individualized drug efficacy testing. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2049-E2061, 2016.

Melanoma: Advances in Targeted Therapy and Molecular Markers

PURPOSE AND DESIGN

In recent years, there have been dramatic improvements in the diagnosis and treatment of patients with melanoma. The development of molecular markers and associated targeted therapies have given new hope to subsets of patients with advanced disease. Here we discuss the most important advances in molecular targeted therapy and how these developments are likely to affect the practice of the clinical surgeon.

RESULTS AND CONCLUSIONS

Germ-line and somatic mutations are common in melanoma and provide prognostic information that can now be harnessed to provide a more personalized approach to cancer treatment. BRAF mutation at the V600 position is the most commonly identified mutation in patients with melanoma. Treatment with targeted inhibitors in patients with BRAF-mutant melanoma has afforded dramatic responses in about half of selected patients. Unfortunately, disease control is not durable and recurrences are common. We predict an increasing role for the surgeon in the multidisciplinary treatment of patients with metastatic disease, as well as a role for molecular profiling in patients with high-risk early stage disease. Further, we are only beginning to understand the prognostic significance of various gene mutations in patients with melanoma.

Establishment and characterization of a human papillomavirus type 16-positive tonsillar carcinoma xenograft in BALB/c nude mice

BACKGROUND

Among head and neck cancers, human papillomavirus type 16 (HPV16) is associated with tonsillar carcinomas. Despite this, no HPV16-positive tonsillar cancer cell line has been established in nude mice.

METHODS

Fresh tonsillar carcinoma biopsies were obtained from 23 patients and implanted subcutaneously into nude mice (BALB/c, nu/nu).

RESULTS

After 7 months, one xenograft was established. The primary tumor harbored 2.7 copies (95% confidence interval = 2.4-2.9) of HPV16/cell and displayed 99.9% (7904/7906) nucleotide identity to HPV16 (EU118173.1). The xenograft showed increased methylation in two E2-binding sites of the HPV16 genome. Both episomal and integrated HPV16 were detected in the original tumor and in 14 xenografts from the second passage. From this passage, a viral load of 6.4 copies/cell (range = 4.6-9.6) and 3.7 (range = 1.0-5.5) E7-mRNA transcripts/HPV16-genome were detected.

CONCLUSION

This xenograft represents the first established HPV16-positive tonsillar tumor in nude mice and could provide an experimental system of HPV16-positive tonsillar cancers.

The impact of human papillomavirus infection on the survival and treatment response of patients with esophageal cancers

OBJECTIVE

This study aimed to investigate the impact of human papillomavirus (HPV) infection on the prognosis and treatment response of esophageal squamous cell carcinoma (ESCC).

METHODS

We examined the presence and subtypes of HPV in the tumors by polymerase chain reaction and sequencing in 150 ESCC patients. Their clinicopathological characteristics, treatment response and survival were further analyzed according to the presence of HPV infection.

RESULTS

Of 150 ESCC tumor samples, 27 (18.0%) were HPV-positive, of which 22 (81.5%) had HPV-16 infection. The risk of developing multifocal ESCC was not significantly different in the HPV-positive and HPV-negative groups (29.6% vs 28.5%, P = 0.90). In subgroup analysis, patients with HPV-16-positive advanced ESCC had a significantly better survival than those with HPV-negative ESCC (3-year survival: 55% vs 21%, log-rank P = 0.03). Cox proportional hazards model showed that the presence of HPV-16 was associated with a significant reduction in the mortality rate (hazard ratio 0.41, 95% CI 0.18-0.96). Patients with HPV-16 infection had better response to chemoradiotherapy (CRT) than those without HPV-16 infection (P = 0.026).

CONCLUSIONS

In patients with advanced ESCC, HPV-16-positive patients had a significantly favorable survival, especially those who received CRT. Larger scale studies are needed to determine the causal relationship.

CCI-779 (Temsirolimus) exhibits increased anti-tumor activity in low EGFR expressing HNSCC cell lines and is effective in cells with acquired resistance to cisplatin or cetuximab

Background

The mammalian target of rapamycin (mTOR) signaling pathway plays a pivotal role in numerous cellular processes involving growth, proliferation and survival. The purpose of this study was to investigate the anti-tumoral effect of the mTOR inhibitor (mTORi) CCI-779 in HNSCC cell lines and its potency in cisplatin- and cetuximab-resistant cells.

Methods

A panel of 10 HNSCC cell lines with differences in TP53 mutational status and basal cisplatin sensitivity and two isogenic models of acquired resistance to cisplatin and cetuximab, respectively were studied. Cell survival after treatment with CCI-779, cisplatin and cetuximab alone or in combination was determined by MTT assays. Potential predictive biomarkers for tumor cell sensitivity to CCI-779 were evaluated.

Results

We observed considerable heterogeneity in sensitivity of HNSCC cell lines to CCI-779 monotherapy. Sensitivity was observed in TP53 mutated as well as wild-type cell lines. Total and p-EGFR expression levels but not the basal activity of the mTOR and MAPK signaling pathways were correlated with sensitivity to CCI-779. Resistant cells with increased EGFR activation could be sensitized by the combination of CCI-779 with cetuximab. Interestingly, cell lines with acquired resistance to cisplatin displayed a higher sensitivity to CCI-779 whereas cetuximab-resistant cells were less sensitive to the drug, but could be sensitized to CCI-779 by EGFR blockade.

Conclusions

Activity of CCI-779 in HNSCC cells harboring TP53 mutations and displaying a phenotype of cisplatin resistance suggests its clinical potential even in patients with dismal outcome after current standard treatment. Cetuximab/mTORi combinations might be useful for treatment of tumors with high expression of EGFR/p-EGFR and/or acquired cetuximab resistance. This combinatorial treatment modality needs further evaluation in future translational and clinical studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0456-6) contains supplementary material, which is available to authorized users.

Beyond BRAF(V600): clinical mutation panel testing by next-generation sequencing in advanced melanoma

The management of melanoma has evolved due to improved understanding of its molecular drivers. To augment the current understanding of the prevalence, patterns, and associations of mutations in this disease, the results of clinical testing of 699 advanced melanoma patients using a pan-cancer next generation sequencing (NGS) panel of hotspot regions in 46 genes were reviewed. Mutations were identified in 43 of the 46 genes on the panel. The most common mutations were BRAF^V600 (36%), NRAS (21%), TP53 (16%), BRAF^Non-V600 (6%), and KIT (4%). Approximately one-third of melanomas had >1 mutation detected, and the number of mutations per tumor was associated with melanoma subtype. Concurrent TP53 mutations were the most frequent event in tumors with BRAF^V600 and NRAS mutations. Melanomas with BRAF^Non-V600 mutations frequently harbored concurrent NRAS mutations (18%), which were rare in tumors with BRAF^V600 mutations (1.6%). The prevalence of BRAF^V600 and KIT mutations were significantly associated with melanoma subtypes, and BRAF^V600 and TP53 mutations were significantly associated with cutaneous primary tumor location. Multiple potential therapeutic targets were identified in metastatic unknown primary and cutaneous melanomas that lacked BRAF^V600 and NRAS mutations. These results enrich our understanding of the patterns and clinical associations of oncogenic mutations in melanoma.

Immunologic and metabolic characteristics of HPV-negative and HPV-positive head and neck squamous cell carcinomas are strikingly different

An HPV infection is involved in the etiology of about 25 % of head and neck squamous cell carcinomas (HNSCC). It has been postulated that a strong antitumoral immune response in HPV-positive tumors represents an important underlying mechanism for their good response to therapy. Recently, the Warburg phenomenon has returned to the center of attention because it affects antitumoral immune response and response to therapy. Accumulation of tumor cell-derived lactate inhibits cytotoxic T cells, as these, analogous to cancer cells, depend on glycolysis and lactate secretion for fulfillment of energy needs. Sparse information exists on the Warburg effect in HNSCC. This study aimed to characterize the metabolic and immunological features of HPV-negative and HPV-positive HNSCC. An immunohistochemical analysis of oropharyngeal carcinomas showed an enhanced antitumoral immune response (CD8/CD4 ratio) together with increased levels of proteins involved in transmembranous metabolite transportation (GLUT1 and CD147) and respiratory metabolism (COX5B) in HPV-positive tumors as compared to HPV-negative tumors. mRNA and Western blot analyses of an HPV-positive and HPV-negative HNSCC cell line revealed metabolic characteristics similar to the in vivo situation. Additionally, the HPV-negative cell line showed stronger extracellular lactate accumulation. In contrast, the HPV-positive cell line presented with better adaption to lactic acidosis suggesting an ability to metabolize lactate. Our results indicate that HPV-positive and HPV-negative carcinomas do not only differ in terms of tumor immune microenvironment, but also in terms of tumor metabolism, characterized by an increased glucose and respiratory metabolism together with decreased lactate accumulation in HPV-positive HNSCC. Therefore, targeting metabolic pathways could represent a promising adjunct in the therapy of HPV-positive HNSCC.

Chk1/2 inhibition overcomes the cisplatin resistance of head and neck cancer cells secondary to the loss of functional p53

Despite the use of multimodality therapy using cisplatin to treat patients with advanced stage squamous cell carcinoma of the head and neck (HNSCC), there is an unacceptably high rate of treatment failure. TP53 is the most commonly mutated gene in HNSCC, and the impact of p53 mutation on response to cisplatin treatment is poorly understood. Here, we show unambiguously that wild-type TP53 (wtp53) is associated with sensitivity of HNSCC cells to cisplatin treatment, whereas mutation or loss of TP53 is associated with cisplatin resistance. We also show that senescence is the major cellular response to cisplatin in wtp53 HNSCC cells and that cisplatin resistance in p53-null or -mutant TP53 cells is due to their lack of senescence. Given the dependence on checkpoint kinase (Chk)1/2 kinases to mediate the DNA damage response in p53-deficient cells, there is potential to exploit this to therapeutic advantage through targeted inhibition of the Chk1/2 kinases. Treatment of p53-deficient HNSCC cells with the Chk inhibitor AZD7762 sensitizes them to cisplatin through induction of mitotic cell death. This is the first report showing the ability of a Chk kinase inhibitor to sensitize TP53-deficient HNSCC to cisplatin in a synthetic lethal manner, which has significance given the frequency of TP53 mutations in this disease and because cisplatin has become part of standard therapy for aggressive HNSCC tumors. These preclinical data provide evidence that a personalized approach to the treatment of HNSCC based on Chk inhibition in p53-mutant tumors may be feasible.

HNSCC cell lines positive for HPV and p16 possess higher cellular radiosensitivity due to an impaired DSB repair capacity

BACKGROUND AND PURPOSE

When treated by radiotherapy, patients with squamous cell carcinomas of the head and neck (HNSCC) positive for HPV and p16(INK4a) possess a clearly favorable prognosis as compared to those with HPV-negative HNSCC. The aim of this work was to study whether the better outcomes might be caused by an enhanced cellular radiosensitivity.

MATERIALS AND METHODS

The radiation response of five HPV/p16(INK4a)-positive and five HPV-negative cell lines was characterized with regard to cellular radiosensitivity by colony formation assay. Furthermore G1- and G2-arrest, apoptosis and residual DNA double-strand breaks (DSB) were analyzed by the colcemid-based G1-efflux assay, propidium iodide staining, the detection of PARP cleavage, the fluorescence-based detection of caspase activity and the immunofluorescence staining of γH2AX and 53BP1 foci.

RESULTS

On average, the cellular radiosensitivity of the HNSCC cell lines positive for HPV and p16(INK4a) was higher as compared to the sensitivity of a panel of five HPV-negative HNSCC cell lines (SF3=0.2827 vs. 0.4455). The higher sensitivity does not result from increased apoptosis or the execution of a permanent G1-arrest, but is rather associated with both, elevated levels of residual DSBs and extensive G2-arrest.

CONCLUSIONS

Increased cellular radiosensitivity due to compromised DNA repair capacity is likely to contribute to the improved outcome of patients with HPV/p16(INK4a)-positive tumors when treated by radiotherapy.

DNA-bound platinum is the major determinant of cisplatin sensitivity in head and neck squamous carcinoma cells

PURPOSE

The combination of systemic cisplatin with local and regional radiotherapy as primary treatment of head and neck squamous cell carcinoma (HNSCC) leads to cure in approximately half of the patients. The addition of cisplatin has significant effects on outcome, but despite extensive research the mechanism underlying cisplatin response is still not well understood.

METHODS

We examined 19 HNSCC cell lines with variable cisplatin sensitivity. We determined the TP53 mutational status of each cell line and investigated the expression levels of 11 potentially relevant genes by quantitative real-time PCR. In addition, we measured cisplatin accumulation and retention, as well as the level of platinum-DNA adducts.

RESULTS

We found that the IC50 value was significantly correlated with the platinum-DNA adduct levels that accumulated during four hours of cisplatin incubation (p = 0.002). We could not find a significant correlation between cisplatin sensitivity and any of the other parameters tested, including the expression levels of established cisplatin influx and efflux transporters. Furthermore, adduct accumulation did not correlate with mRNA expression of the investigated influx pumps (CTR1 and OCT3) nor with that of the examined DNA repair genes (ATR, ATM, BRCA1, BRCA2 and ERCC1).

CONCLUSION

Our findings suggest that the cisplatin-DNA adduct level is the most important determinant of cisplatin sensitivity in HNSCC cells. Imaging with radio-labeled cisplatin might have major associations with outcome.

Clinical outcomes of radiation-based locoregional therapy in locally advanced head and neck squamous cell carcinoma patients not responding to induction chemotherapy

OBJECTIVE

The purpose of this study was to evaluate the efficacy of radiation-based locoregional therapy for locally advanced head and neck squamous cell carcinoma (LA-HNSCC) patients who did not respond to induction chemotherapy (IC).

STUDY DESIGN

Outcomes after radiation-based locoregional therapy were retrospectively analyzed.

RESULTS

Among a total of 208 patients treated with IC, 46 (22.1%) did not respond. After IC, patients were treated with radiotherapy (RT), concurrent chemoradiotherapy (CCRT), or surgery with or without postoperative RT. Among the 46 nonresponders, 17 (37.8%) patients underwent surgery and 28 (62.2%) were treated with RT or CCRT. Responses to subsequent RT or CCRT for 26 evaluable patients were as follows: complete response=7 (26.9%), partial response=9 (34.6%), stable disease=4 (15.4%), and progressive disease=6 (23.1%).

CONCLUSION

A significant proportion of LA-HNSCC patients who did not respond to IC can benefit from subsequent RT or CCRT.

Genetic variants in p53-related genes confer susceptibility to second primary malignancy in patients with index squamous cell carcinoma of head and neck

Because of their important roles in mediating the stabilization and expression of p53, we hypothesized that high-risk genotypes of polymorphisms in p53-related genes, including p53, p73, p14(ARF), MDM2 and MDM4, may be associated with an increased risk of second primary malignancy (SPM) after index squamous cell carcinoma of the head and neck (SCCHN). We analyzed data from a cohort of 1283 patients with index SCCHN who were recruited between 1995 and 2007 at MD Anderson Cancer Center and followed for SPM development. Patients were genotyped for nine polymorphisms of p53-related genes. A log-rank test and Cox models were used to compare SPM-free survival and risk. Our results demonstrated that each p53-related polymorphism had a moderate effect on increased SPM risk, but when we combined risk genotypes of these nine polymorphisms together, we found that SPM-free survival was significantly shorter among risk groups with a greater number of combined risk genotypes. SPM risk increased with increasing number of risk genotypes (P < 0.0001 for trend). Compared with the low-risk group (0-3 combined risk genotypes), both the medium-risk (4-5 combined risk genotypes) and high-risk (6-9 combined risk genotypes) groups had significantly increased SPM risk [hazard ratio (HR): 1.6; 95% confidence interval (CI): 1.0-2.6 and HR: 3.0; 95% CI: 1.8-5.0, respectively]. Moreover, such significant associations were even higher in several subgroups. Our findings suggest that combined risk genotypes of p53-related genes may jointly modify SPM risk, especially in patients who are smokers and those with index non-oropharyngeal cancers. However, larger studies are needed to validate our findings.

Systemic therapy strategies for head-neck carcinomas: Current status

Head and neck cancers, most of which are squamous cell tumours, have an unsatisfactory prognosis despite intensive local treatment. This can be attributed, among other factors, to tumour recurrences inside or outside the treated area, and metastases at more distal locations. These tumours therefore require not only the standard surgical and radiation treatments, but also effective systemic modalities. The main option here is antineoplastic chemotherapy, which is firmly established in the palliative treatment of recurrent or metastatic stages of disease, and is used with curative intent in the form of combined simultaneous or adjuvant chemoradiotherapy in patients with inoperable or advanced tumour stages. Neoadjuvant treatment strategies for tumour reduction before surgery have yet to gain acceptance. Induction chemotherapy protocols before radiotherapy have to date been used in patients at high risk of distant metastases or as an aid for decision-making ("chemoselection") in those with extensive laryngeal cancers, prior to definitive chemoradiotherapy or laryngectomy. Triple-combination induction therapy (taxanes, cisplatin, 5-fluorouracil) shows high remission rates with significant toxicity and, in combination with (chemo-)radiotherapy, is currently being compared with simultaneous chemoradiotherapy; the current gold standard with regards to efficacy and long-term toxicity.A further systemic treatment strategy, called "targeted therapy", has been developed to help increase specificity and reduce toxicity. An example of targeted therapy, EGFR-specific antibodies, can be used in palliative settings and, in combination with radiotherapy, to treat advanced head and neck cancers. A series of other novel biologicals such as signal cascade inhibitors, genetic agents, or immunotherapies, are currently being evaluated in large-scale clinical studies, and could prove useful in patients with advanced, recurring or metastatic head and neck cancers. When developing a lasting, individualised systemic tumour therapy, the critical evaluation criteria are not only efficacy and acute toxicity but also (long-term) quality-of-life and the identification of dedicated predictive biomarkers.

Susceptibility to cytotoxic T cell lysis of cancer stem cells derived from cervical and head and neck tumor cell lines

PURPOSE

To explore cancer stem cell susceptibility to a host's cytotoxic T lymphocyte (CTL)-mediated immune response.

METHODS

We compared the susceptibility of putative CSC generated from cancer cell lines to immunologic recognition and killing by alloantigen-specific CD8(+) CTL. CSC-enriched spheroid culture-derived cells (SDC) exhibited higher expression of ALDH, ICAM1 and of stem/progenitor cell markers on all 3 tumor cell lines investigated and lower MHC class I on the cervical cancer cell line as compared to their monolayer-derived cells (MDC).

RESULTS

The expression of ICAM1 and MHCI was upregulated by IFN-γ treatment. CSC populations were less sensitive to MHC class I-restricted alloantigen-specific CD8(+) CTL lysis as compared to matched MDC. IFN-γ pretreatment resulted in over-proportionally enhanced lysis of SDC. Finally, the subset of ALDH(high) expressing SDC presented more sensitivity toward CD8(+) CTL killing than the ALDH(low) SDC.

CONCLUSIONS

Tumor therapy resistance has been attributed to cancer stem cells (CSC). We show in vitro susceptibility of CSC to CTL-mediated lysis. Immunotherapy targeting of ALDH(+) CSC may therefore be a promising approach. Our results and method may be helpful for the development and optimization of adjuvants, as here exemplified for INF-γ, for CSC-targeted vaccines, independent of the availability of CSC-specific antigens.

Squamous cell carcinomas of the head and neck in Fanconi anemia: risk, prevention, therapy, and the need for guidelines

Fanconi anemia (FA) is a rare recessive DNA repair disorder that is clinically characterized by congenital malformations, progressive bone marrow failure, and increased incidence of malignancies, especially acute myeloid leukemia and squamous cell carcinomas of the head and neck (HNSCCs) and the anogenital regions. On a cellular level, typical features of the disorder are a high degree of genomic instability and an increased sensitivity to bi-functionally alkylating agents. So far, germ-line defects in 15 different FA genes have been identified. Some of these FA genes are also established as tumor susceptibility genes for familiar cancers.In recent years, the prevention and therapy of HNSCCs in FA patients has become more important as the percentage of patients surviving into adulthood is rising. HNSCCs appear in very young FA patients without common risk factors. Since cisplatin-based chemotherapy in combination with radiotherapy, essential parts of the standard treatment approach for sporadic HNSCCs, cannot be used in FA patients due to therapy-associated toxicities and mortalities even with reduced dosing, surgery is the most important treatment option for HNSCCs, in FA patients and requires an early and efficient detection of malignant lesions. So far, no uniform treatment protocol for the management of HNSCCs in FA patients exists. Therefore, we propose that the information on affected FA patients should be collected worldwide, practical therapeutic guidelines developed and national treatment centers established.

New Concepts for Translational Head and Neck Oncology: Lessons from HPV-Related Oropharyngeal Squamous Cell Carcinomas

Human papillomavirus (HPV) infection is well established as an etiological agent responsible for a number of pathologies affecting the stratified epithelia of skin and anogenital sites. More recently, the infection by (mucosal) high-risk HPV types has also been found to be causally associated with squamous cell carcinoma in the head and neck region (HNSCC), especially in the oropharynx. Intriguingly, HPV-related oropharyngeal squamous cell carcinomas (OPSCC) represent a distinct clinical entity compared to HPV-negative tumors with particular regard to treatment–response and survival outcome. The association between HPV infection and OPSCC may therefore have important implications for the prevention and/or treatment of OPSCC. The improved survival of patients with HPV-related tumors also raises the question, as to whether a better understanding of the underlying differences may help to identify new therapeutic concepts that could be used in targeted therapy for HPV-negative and improved therapy for HPV-positive cancers. This review summarizes the most recent advances in our understanding of the molecular principles of HPV-related OPSCC, mainly based on functional genomic approaches, but also emphasizes the significant role played by the tumor microenvironment, especially the immune system, for improved clinical outcome and differential sensitivity of HPV-related tumors to current treatment options.

Downregulation of SMG-1 in HPV-positive head and neck squamous cell carcinoma due to promoter hypermethylation correlates with improved survival

PURPOSE

Human papillomavirus (HPV) is linked with a subset of head and neck squamous cell carcinomas (HNSCC). HPV-positive HNSCCs show a better prognosis than HPV-negative HNSCCs, which may be explained by sensitivity of the HPV-positive HNSCCs to ionizing radiation (IR). Although the molecular mechanism behind sensitivity to IR in HPV-positive HNSCCs is unresolved, DNA damage response (DDR) might be a significant determinant of IR sensitivity. An important player in the DDR, SMG-1 (suppressor with morphogenetic effect on genitalia), is a potential tumor suppressor and may therefore be deregulated in cancer. No studies have yet been conducted linking defects in SMG-1 expression with cancer. We investigated whether deregulation of SMG-1 could be responsible for defects in the DDR in oropharyngeal HNSCC.

EXPERIMENTAL DESIGN

Expression and promoter methylation status of SMG-1 were investigated in HNSCCs. To identify a functional link between HPV infection and SMG-1, we transfected the HPV-negative cells with an E6/E7 expression construct. SMG-1 short hairpin RNAs were expressed in HPV-negative cells to estimate survival upon IR.

RESULTS

Forced E6/E7 expression in HPV-negative cells resulted in SMG-1 promoter hypermethylation and decreased SMG-1 expression. Due to promoter hypermethylation, HPV-positive HNSCC cells and tumors express SMG-1 at lower levels than HPV-negative SCCs. Depletion of SMG-1 in HPV-negative HNSCC cells resulted in increased radiation sensitivity, whereas SMG-1 overexpression protected HPV-positive tumor cells from irradiation.

CONCLUSIONS

Levels of SMG-1 expression negatively correlated with HPV status in cancer cell lines and tumors. Diminished SMG-1 expression may contribute to the enhanced response to therapy exhibited by HPV-positive HNSCCs.

UM-SCC-104: a new human papillomavirus-16-positive cancer stem cell-containing head and neck squamous cell carcinoma cell line

BACKGROUND

Few human papillomavirus (HPV)(+) head and neck squamous cell carcinoma (HNSCC) cell lines exist. We established University of Michigan-squamous cell carcinoma-104 (UM-SCC-104), a new HPV(+) HNSCC cell line from a recurrent oral cavity tumor, and characterized it for the presence of cancer stem cells (CSCs).

METHODS

Tumor cells were tested for biomarker expression by immunohistology, and the presence of HPV was assessed by several methods.

RESULTS

UM-SCC-104 has a unique genotype, contains HPV-16, and expresses E6/E7. Inoculation of aldehyde dehydrogenase (ALDH)(+) and ALDH(-) cells in an immunocompromised mouse resulted in tumor growth from the ALDH(+) cells after 6 weeks that recapitulated the histology of the primary, whereas ALDH(-) cells did not produce tumors.

CONCLUSION

UM-SCC-104, a new HPV-16, CSC-containing HNSCC cell line will aid in studying recurrent HPV(+) tumors. The aggressive nature of this tumor is consistent with high uniform expression of epidermal growth factor receptor (EGFR) and a functionally significant proportion of ALDH(+) CSCs.

Epithelial-mesenchymal-transition induced by EGFR activation interferes with cell migration and response to irradiation and cetuximab in head and neck cancer cells

BACKGROUND AND PURPOSE

The role of epithelial-mesenchymal transition (EMT) in the poor outcome of EGFR-overexpressing SCCHN was evaluated.

MATERIAL AND METHODS

SCCHN cell lines were characterized for their cell morphology and expression of EGFR and the EMT-associated factors E-cadherin, vimentin and Snail1. The migratory potential of cells was assessed in motility assays. Response to irradiation and cetuximab was determined using clonogenic survival assays.

RESULTS

High basal expression of E-cadherin but low to absent vimentin expression could be observed in all SCCHN cell lines. Although E-cadherin expression levels did not change after treatment with EGF we observed a significant change in cell morphology resembling EMT. SCCHN cells with high basal levels of Snail1 resulting from constitutive EGFR activation were characterized by mesenchymal-like morphology, elevated migratory potential, reduced sensitivity to irradiation and cetuximab but increased sensitivity to the combined treatment.

CONCLUSIONS

Autocrine activation of EGFR leading to EMT is associated with a metastatic phenotype and reduced sensitivity of SCCHN cells to single-modality treatment with cetuximab or irradiation. The potential of Snail1 as biomarker for selection of patients who will mostly benefit from a combination of cetuximab and radiotherapy has to be evaluated in future clinical studies.

Radioimmunotherapy of experimental head and neck squamous cell carcinoma (HNSCC) with E6-specific antibody using a novel HPV-16 positive HNSCC cell line

Background

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide with a poor prognosis. Human papilloma virus (HPV) infection is associated with 20% HNSCC, and 50% of oropharyngeal carcinoma. HPV16 type is detected in 90% of all HPV+ HNSCC. Recently we suggested a fundamentally different approach to treatment of cancers of viral origin by targeting viral antigens on cancer cells with radiolabeled antibodies (mAbs) which promises exquisite specificity of treatment. We aimed at extending this approach to HPV-related head and neck cancer by performing radioimmunotherapy (RIT) targeting E6 and E7 oncogenes with radiolabeled mAbs.

Methods

We first aimed at developing HPV16+ cell line and animal model for RIT of HNSCC as at present there are no commercially available HPV16+ HNSCC cell lines and there is only one HPV+ cell line among the collection maintained by Dusseldorf, Michigan and Turku groups. Commercially available HNSCC cell line FaDu was transfected with pLXSN16E6E7 vector containing HPV16 E6 and E7 genes. Generated novel cell lines were evaluated by PCR and western blot and the tumorigenecity was assessed in nude mice. Proof of principle RIT targeting E6 oncoprotein in 2A3 tumor-bearing nude mice was conducted using unlabeled or 188-Rhenium (¹⁸⁸Re)-labeled C1P5 mAb to E6.

Results

Novel HPV16+ 2A3 cell line reliably expressed E6 oncoprotein. E6 expression was modifiable with proteasome inhibitor MG132 in a dose-dependent manner. The levels of E6 expression in 2A3 cell line were estimated to be around 200 HPV copies per cell. The HPV16+ 2A3 cell line preserved 100% tumorigenicity of parent FaDu cells in nude mice. During RIT of 2A3 tumors in nude mice the relatively low dose of 200 μCi ¹⁸⁸Re-C1P5 mAb was effective in decreasing the tumor growth in comparison with untreated controls. Unlabeled C1P5 mAb also caused some decrease in tumor progression, however, much less pronounced than ¹⁸⁸Re-C1P5 mAb.

Conclusions

We describe a proof-of-principle RIT study targeting HPV16 E6 oncoprotein with radiolabeled mAb to E6 in a stably transformed HPV16+ HNSCC cell line and tumor model in nude mice, and demonstrate potential utility of RIT as a novel molecular targeted therapy for HNSCC.

In vitro chemosensitivity of head and neck cancer cell lines

Background

Systemic treatment of head and neck squamous cell carcinoma (HNSCC) includes a variety of antineoplastic drugs. However, drug-resistance interferes with the effectiveness of chemotherapy. Preclinical testing models are needed in order to develop approaches to overcome chemoresistance.

Methods

Ten human cell lines were obtained from HNSCC, including one with experimentally-induced cisplatin resistance. Inhibition of cell growth by seven chemotherapeutic agents (cisplatin, carboplatin, 5- fluorouracil, methotrexate, bleomycin, vincristin, and paclitaxel) was measured using metabolic MTT-uptake assay and correlated to clinically-achievable plasma concentrations.

Results

All drugs inhibited cell growth in a concentration-dependent manner with an IC50 comparable to that achievable in vivo. However, response curves for methotrexate were unsatisfactory and for paclitaxel, the solubilizer cremophor EL was toxic. Cross-resistance was observed between cisplatin and carboplatin.

Conclusion

Chemosensitivity of HNSCC cell lines can be determined using the MTT-uptake assay. For DNA-interfering cytostatics and vinca alkaloids this is a simple and reproducible procedure. Determined in vitro chemosensitivity serves as a baseline for further experimental approaches aiming to modulate chemoresistance in HNSCC with potential clinical significance.

Assay-based response evaluation in head and neck oncology: requirements for better decision making

This article gives an overview on different current strategies of assay-based response evaluation in head and neck squamous cell carcinomas (HNSCC) and critically summarizes their role and needs for future clinical evaluation. Due to a growing amount of data of phase III clinical trials of multimodality treatment options for HNSCC, treatment planning in regard to optimal outcome is becoming an interdisciplinary challenge. New concepts such as induction chemotherapy with bi- or ternary combinations of chemotherapeutics, integration of targeted therapies, concurrent and sequential chemoradiation concepts, and multimodality-based organ preservation strategies strongly compete with traditional definitive surgical procedures. Moreover, the outcome is difficult to predict due to heterogeneity of a tumor's response, impaired late functional outcome, and increased late toxicity if simultaneously applied to radiation. Retrospectively looking at non-responders with tumors classified as resectable, primary surgery is very likely to have achieved better results, since chemoradiation causes a high degree of early and late toxicities leading to extremely complicated terms and conditions in surgery following current multimodal therapeutic strategies. Unfortunately, predictive information on response characteristics of a given tumor before starting the therapy is not available in daily routine, although heterogeneity in response of a given tumor entity to treatments has been known for decades. Therefore, current therapy strategies for HNSCC still have to ignore this fact, creating an urgent need for the development of proper predictive assays. There are interesting clinical observations showing that response on induction chemotherapy may predict the outcome after radiotherapy. Some trials use this empiric phenomenon to pre-select non-responders for primary surgical treatment avoiding severe salvage complications after failure of complete chemoradiation treatment. Moving one step further, recent literature and our own investigations implicate that response evaluation of the individual patient's HNSCC in a suitable ex vivo assay just before starting the treatment is mature for clinical research. To this end, essential needs and hints are addressed and discussed.

The molecular pathogenesis of head and neck cancer

Head and neck cancer arises from a series of molecular alterations progressive from dysplasia to carcinoma in situ, and finally invasive carcinoma. Risk factors associated with head and neck cancer include tobacco, alcohol and viral infection. There are genetic alterations in pre-cancerous cells that contribute to transformation. The accumulation of these alterations facilitates tumor development. Additionally, the tumor microenvironment enables tumor progression. The cooperative effect of molecular alterations in the tumor cells and compensatory microenvironment changes enable tumors to invade and metastasize. This review focuses on the genes and molecules altered during the progression of head and neck cancer with an emphasis on the genetic, molecular and phenotypic changes during the pathogenesis of head and neck cancer. Therapeutic strategies that target key changes in the tumor cells and/or stromal cells in the tumor microenvironment are discussed.

Heterogeneity of epithelial and stromal cells of head and neck squamous cell carcinomas in ex vivo chemoresponse

BACKGROUND

Valid prediction of the effectiveness of chemotherapeutic agents in individual head and neck squamous cell carcinoma (HNSCC) is desirable and might be achieved using ex vivo assays.

METHODS

Three biopsies from each of 15 HNSCC were taken, minced and digested by collagenase. The digested HNSCC was added to serial dilutions of either cisplatin (CIS) or docetaxel (DTX), which were prepared under flavin-protecting conditions in ECM-coated microtiterplates. After 72-h incubation, cultures were methanol-fixed and Giemsa-stained. The cutoff concentration (COC; concentration completely suppressing colony formation) for epithelial cells (EC) and stromal cells (SC) was evaluated.

RESULTS

12/15 HNSCC (80%) were evaluable. Despite significant correlation of COC of CIS in respect of colony formation of EC or SC, no significant differences in response of individual HNSCC specimens were found in the t test for paired samples (p > 0.16). The same applied to DTX. However, EC and SC showed heterogeneity in chemoresponses leading to COC variability of more than one titration step in 44.1% (CIS) and 20% of HNSCC (DTX). No significant correlation between the COC of both cell populations was found in HNSCC specimens.

CONCLUSIONS

The ex vivo chemoresponse of EC and SC of HNSCC must be analyzed separately.

Radiation response in two HPV-infected head-and-neck cancer cell lines in comparison to a non-HPV-infected cell line and relationship to signaling through AKT

PURPOSE

Human papilloma virus (HPV)-associated cancers of the head and neck (H&N) are increasing in frequency and are often treated with radiation. There are conflicting data in the literature regarding the radiation response in the presence of HPV infection, with some data suggesting they may be more sensitive to radiation. There are few studies looking at in vitro effects of HPV and further sensitization by inhibitors of specific signaling pathways. We are in the process of starting a clinical trial in H&N cancer patients using nelfinavir (NFV) (which inhibits Akt) and it would be important to know the effect of HPV on radiation response +/- NFV.

METHODS AND MATERIALS

Two naturally infected HPV-16 cell lines (UPCI-SCC90 and UMSCC47) and the HPV-negative SQ20B H&N squamous carcinoma cells were used. Western blots with or without 10 uM NFV were done to evaluate signaling from the PI3K-Akt pathway. Clonogenic assays were done in the three cell lines with or without NFV.

RESULTS

Both UPCI-SCC90 and UMSCC47 cells were sensitive to radiation as compared with SQ20B and the degree corresponded to Akt activation. The SQ20B cell line has an activating mutation in EGFR resulting in phosphorylation (P) of Akt; UMSCC47 has decreased P-phosphatase and TENsin (PTEN), resulting in increased P-Akt; UPCI-SCC90 had overexpression of P-PTEN and decreased P-Akt. NFV resulted in downregulation of Akt in all three cell lines, resulting in sensitization to radiation.

CONCLUSIONS

HPV-infected H&N cancers are sensitive to radiation. The degree of sensitivity correlates to Akt activation and they can be further sensitized by NFV.

Controversies surrounding human papilloma virus infection, head & neck vs oral cancer, implications for prophylaxis and treatment

Head & Neck Cancer (HNC) represents the sixth most common malignancy worldwide and it is historically linked to well-known behavioural risk factors, i.e., tobacco smoking and/or the alcohol consumption. Recently, substantial evidence has been mounting that Human Papillomavirus (HPV) infection is playing an increasing important role in oral cancer. Because of the attention and clamor surrounding oral HPV infection and related cancers, as well as the use of HPV prophylactic vaccines, in this invited perspective the authors raise some questions and review some controversial issues on HPV infection and its role in HNC, with a particular focus on oral squamous cell carcinoma.

The problematic definition and classification of HNC will be discussed, together with the characteristics of oral infection with oncogenic HPV types, the frequency of HPV DNA detection in HNC, the location of HPV-related tumours, the severity and prognosis of HPV-positive HNC, the diagnosis of oral HPV infection, common routes of oral infection and the likelihood of oro-genital HPV transmission, the prevention of HPV infection and novel therapeutic approaches.

Recent advances in oral oncology 2008; squamous cell carcinoma imaging, treatment, prognostication and treatment outcomes

This paper provides a synopsis of the main papers on diagnosis, imaging, treatment, prognostication and treatment outcomes in patients with oral and oropharyngeal squamous cell carcinoma (OSCC) and head and neck SCC (HNSCC) published in 2008 in Oral Oncology - an international interdisciplinary journal which publishes high quality original research, clinical trials and review articles, and all other scientific articles relating to the aetiopathogenesis, epidemiology, prevention, clinical features, diagnosis, treatment and management of patients with neoplasms in the head and neck, and orofacial disease in patients with malignant disease.