Targeted Therapy of Head and Neck Cancer

Personalized Treatment of Recurrent, Metastatic Head and Neck Cancer Guided by Patient-Derived Xenograft Models

Recurrent or metastatic head and neck squamous cell carcinoma (RMHNSCC) is associated with a poor prognosis and short survival duration. There is an urgent need to identify personalized predictors of drug response to guide the selection of the most effective therapy for each individual recurrence. We tested the feasibility of patient-derived xenografts (PDX) for guiding their RMHNSCC salvage treatment. Fresh tumor samples from eligible, consented patients were implanted into mice. Established tumors were expanded in mouse PDX cohorts to identify responses to candidate salvage drug treatments in parallel testing. Patients alive and suitable for chemotherapy were treated based on responses determined by PDX testing. Nine patient tumors were successfully engrafted in mice with an average time of 89.2±41.7 days. Four patients' PDX models underwent parallel drug testing. Two patients received PDX-guided therapy. In one of these patients, single agents of cetuximab and paclitaxel demonstrated the best responses in the PDX model, and this patient exhibited sequential partial responses to each drug, including a 17-month clinical response to cetuximab. The main limitation of PDX testing for RMHNSCC was the time delay in obtaining testing results. Despite this, parallel PDX testing may be feasible for a subset of patients and appears to correlate with clinical benefit.

Molecular Biomarkers of Malignant Transformation in Head and Neck Dysplasia

Head and neck squamous cell carcinoma (HNSCC) and its treatments are associated with substantial morbidity, often resulting in cosmetic deformity and loss of physiologic functions including speech and swallowing. Despite advancements in treatment, 5-year survival rates for mucosal malignancies remain below 70%. Effective prevention of HNSCC demands an understanding of the molecular pathways of carcinogenesis. Specifically, defining features of pre-cancerous dysplastic lesions that indicate a better or worse prognosis is necessary to help identify patients who are likely to develop a carcinoma and allow a more aggressive approach to management. There remains a need for identification of biomarkers that can provide both early prognostic and predictive value in clinical decision-making by serving as both therapeutic targets as well as predictors of therapy response. Here, we comprehensively review the most frequently altered molecular biomarkers of malignant transformation in head and neck dysplasia. These markers are involved in a wide range of cellular processes in head and neck carcinogenesis, including extracellular matrix degradation, cell motility and invasion, cell-cell adhesion, solute transport, immortalization, metabolism, the cell cycle and apoptosis, transcription, and cell signaling.

Antitumor effects of valdecoxib on hypopharyngeal squamous carcinoma cells

The antitumoral effects of valdecoxib (Val), an United States Food and Drug Administration-approved anti-inflammatory drug that was withdrawn due to the side effects of increased risk of cardiovascular adverse events, were investigated in hypopharyngeal squamous cell carcinoma cells by performing a cell viability assay, transwell assay, immunofluorescence imaging, and Western blotting. Val markedly inhibited cell viability with an IC50 of 67.3 μM after 48 h of treatment, and also downregulated cell cycle proteins such as Cdks and their regulatory cyclin units. Cell migration and invasion were severely suppressed by inhibiting integrin α4/FAK expression. In addition, Val activated the cell cycle checkpoint CHK2 in response to excessive DNA damage, which led to the activation of caspase-3/9 and induced caspase-dependent apoptosis. Furthermore, the signaling cascades of the PI3K/AKT/mTOR and mitogen-activated protein kinase pathways were significantly inhibited by Val treatment. Taken together, our results indicate that Val can be used for the treatment of hypopharyngeal squamous cell carcinoma.

Flavonoids Induce Migration Arrest and Apoptosis in Detroit 562 Oropharynx Squamous Cell Carcinoma Cells

Despite advances in the treatment of head and neck squamous cell carcinoma (HNSCC), the morbidity remains at a high level due to the resistance of SCC cells to chemotherapeutics. This study aimed to determine and compare the magnitude of the flavonoids’ effectiveness in activating apoptosis and migration arrest in HNSCC cells in vitro. Methods: Head and neck SCC cells of the Detroit 562 line were exposed to a range of concentrations (5–100 μM) of quercetin (Que), hesperidin (Hes) and rutin (Rut) for 24 and 48 h. The SCC cell viability and migration rate were investigated using cytotoxicity and migration inhibition assays. Muse Cell Analyzer flow cytometry was utilized to quantitatively assess the apoptosis rate of Detroit 562 cells exposed to Que, Hes and Rut. The morphology of the SCC cells was evaluated via hematoxylin-eosin staining. Results: The viability diminishment of the Detroit 562-line cells treated with Que, Hes and Rut for 48 h revealed a significant dose-dependent trend, relatively equal for three substances, whereas the most noticeable cytotoxic effect observed for Hes. Exposure to Hes and Rut exhibited a dose-dependent increased proportion of apoptotic SCC cells, at either necrosis or late apoptosis stage. Detroit 562 SCC migration rate and cells motility were halted for the 100 µM dose of Hes and Que. The comparative results elucidated that Hesperidin and Quercetin achieved a more potent reduction of Detroit 562 migration at 24 h. Conclusions: Hesperidin, rutin and quercetin are capable of inducing apoptosis and migration arrest in the Detroit 562 cell line to various extents, resulting in proapoptotic attenuating effects at different magnitudes.

LINC00461 facilitates HNSCC development and reduces chemosensitivity by impairing miR-195-mediated inhibition of HOXA10

Homeobox A10 (HOXA10) has been regarded to serve as an oncogene in head and neck squamous cell carcinoma (HNSCC). This study was intended to explore the interaction among the long intergenic noncoding RNA 00461 (LINC00461), microRNA (miR)-195, and HOXA10, and to investigate its role in epithelial-mesenchymal transition (EMT) and chemoresistance in HNSCC. The effects of LINC00461, miR-195, and HOXA10 on the EMT and chemoresistance of HNSCC cells were analyzed by comprehensive analysis of gain- and loss-of-function techniques. The intimate relationships among LINC00461, miR-195, and HOXA10 were investigated by several procedures such as RNA-binding protein immunoprecipitation, RNA pull-down, and dual-luciferase reporter assays. A xenotransplantation tumor model in nude mice was established for the assessment of the tumorigenic ability of the cells in vivo. Our findings indicated that LINC00461 was highly expressed in HNSCC and its overexpression induced EMT and precipitated the chemoresistance of HNSCC cells to cisplatin. The LINC00461 could bind to miR-195 while miR-195 targeted HOXA10 independently. Moreover, LINC00461 impaired miR-195-mediated inhibition of HOXA10 to induce EMT and increase the chemoresistance in HNSCC. Tumor weight and volume were reduced by lentivirus-mediated elevation of miR-195 by inhibition of HOXA10, which could be annulled by LINC00461 overexpression. LINC00461 downregulates the expression of miR-195 to subsequently upregulate the expression of HOXA10, thereby promoting EMT and enhancing chemoresistance in HNSCC.

Distinct immune evasion in APOBEC-enriched, HPV-negative HNSCC

Immune checkpoint inhibition leads to response in some patients with head and neck squamous cell carcinoma (HNSCC). Robust biomarkers are lacking to date. We analyzed viral status, gene expression signatures, mutational load and mutational signatures in whole exome and RNA-sequencing data of the HNSCC TCGA dataset (n = 496) and a validation set (DKTK MASTER cohort, n = 10). Public single-cell gene expression data from 17 HPV-negative HNSCC were separately reanalyzed. APOBEC3-associated TCW motif mutations but not total single nucleotide variant burden were significantly associated with inflammation. This association was restricted to HPV-negative HNSCC samples. An APOBEC-enriched, HPV-negative subgroup was identified, that showed higher T-cell inflammation and immune checkpoint expression, as well as expression of APOBEC3 genes. Mutations in immune-evasion pathways were also enriched in these tumors. Analysis of single-cell sequencing data identified expression of APOBEC3B and 3C genes in malignant cells. We identified an APOBEC-enriched subgroup of HPV-negative HNSCC with a distinct immunogenic phenotype, potentially mediating response to immunotherapy.

Magnolia extract is effective for the chemoprevention of oral cancer through its ability to inhibit mitochondrial respiration at complex I

Background

Magnolia extract (ME) is known to inhibit cancer growth and metastasis in several cell types in vitro and in animal models. However, there is no detailed study on the preventive efficacy of ME for oral cancer, and the key components in ME and their exact mechanisms of action are not clear. The overall goal of this study is to characterize ME preclinically as a potent oral cancer chemopreventive agent and to determine the key components and their molecular mechanism(s) that underlie its chemopreventive efficacy.

Methods

The antitumor efficacy of ME in oral cancer was investigated in a 4-nitroquinoline-1-oxide (4NQO)-induced mouse model and in two oral cancer orthotopic models. The effects of ME on mitochondrial electron transport chain activity and ROS production in mouse oral tumors was also investigated.

Results

ME did not cause detectable side effects indicating that it is a promising and safe chemopreventive agent for oral cancer. Three major key active compounds in ME (honokiol, magnolol and 4-O-methylhonokiol) contribute to its chemopreventive effects. ME inhibits mitochondrial respiration at complex I of the electron transport chain, oxidizes peroxiredoxins, activates AMPK, and inhibits STAT3 phosphorylation, resulting in inhibition of the growth and proliferation of oral cancer cells.

Conclusion

Our data using highly relevant preclinical oral cancer models, which share histopathological features seen in human oral carcinogenesis, suggest a novel signaling and regulatory role for mitochondria-generated superoxide and hydrogen peroxide in suppressing oral cancer cell proliferation, progression, and metastasis.

Efficacy of a CDK4/6 Inhibitor in a Patient with Breast Cancer and Liposarcoma: A Case Report and Review of the Literature

BACKGROUND

The cyclin D/cyclin-dependent kinase (CDK)4/6 inhibitor of the CDK4 (INK4)/retinoblastoma (Rb) pathway plays a crucial role in cell cycle progression. Selective CDK4/6 inhibitors specifically target a variety of tumors, with the main focus on hormone receptor(HR)-positive and human epidermal growth factor receptor 2(HER2)-negative breast cancer (BC).

CASE REPORT

We report on the efficacy of neoadjuvant palbociclib and letrozole application in a patient suffering from invasive estrogen receptor (ER)+/HER2- BC and concurrent well-differentiated and dedifferentiated liposarcoma (WD-DDLPS) of the thigh. Clinical and histological workup upon surgery revealed significant regressive changes in both the liposarcoma and the BC. The 24-month follow-up shows no signs of disease.

CONCLUSION

CDK4/6 inhibitors exhibit a high therapeutic potential, although reliable prognostic markers need to be identified.

Histoepigenetic analysis of HPV- and tobacco-associated head and neck cancer identifies both subtype-specific and common therapeutic targets despite divergent microenvironments

Although head and neck squamous cell carcinoma (HNSCC) has in the past been largely associated with tobacco use, human papillomavirus (HPV+) oropharynx cancer has in recent years emerged as the fastest growing type of HNSCC. Patients with HPV+ HNSCC have a better prognosis; however, the 5-year survival for both HPV+ and HPV- subtypes with recurrent or metastatic disease is poor. To gain insights into the tumor microenvironments of both HNSCC subtypes and identify potential therapeutic targets, we performed epigenomic deconvolution on 580 HNSCC samples from the TCGA dataset. Deconvolution revealed distinct molecular and histoepigenetic profiles of the two tumor subtypes, including their cellular composition, epigenomic profiles and gene expression for constituent cell types, and potential cancer cell-specific targets. Our analyses show that high abundance of both CD8 T-cells and B-cells explains better prognosis in HPV+ HNSCC. Deconvolution of gene expression profiles revealed higher expression of the immunotherapy target PD-1 in HPV+ immune cells compared to HPV- cells, suggesting that HPV+ tumors may preferentially benefit from PD-1 targeted therapy. Further analyses identified HPV+ and HPV- cancer cell surface proteins that can also serve as potential targets for therapy. Specifically, Wnt pathway receptor ROR2 is preferentially overexpressed in HPV+ subtypes, suggesting opportunities for development of targeted therapy based on HPV status. In summary, the comprehensive molecular and histoepigenetic analysis of tumor microenvironments by epigenomic deconvolution reveals potential novel biomarkers and targets for precision therapy of HNSCC.

Efficacy of Carboplatin/Paclitaxel-Based Radiochemotherapy in Locally Advanced Squamous Cell Carcinoma of Head and Neck

BACKGROUND

Cisplatin-based chemotherapy (CTX) is commonly used concurrently with radiotherapy for head and neck cancer. The value of CTX regimens other than cisplatin for locally advanced squamous cell carcinoma of head and neck (LASCCHN) has not been well established. Here we compare the outcome of patients treated with different platinum-based chemotherapy regimens.

METHODS

Medical records from 104 patients with LASCCHN treated with radiochemotherapy (RCTX) between February 2013 and August 2016 were analyzed.

RESULTS

All patients were treated with intensity-modulated radiation therapy (51 definitive, 53 postoperative). The median total dose was 66.6 Gy and the median fraction dose was 1.8 Gy. 81 (78%) patients were administered cisplatin CTX, 23 (22%) patients received carboplatin and paclitaxel (CarboTaxol). The rate of recurrence was 38% in patients treated with cisplatin and 30% in CarboTaxol-treated patients (p = 0.6). Regarding the CTX regimens, event-free survival (EFS) was 37 versus 30 months (p = 0.6) and overall survival (OS) was 35 versus 28 months (p = 0.5) in cisplatin group versus CarboTaxol group, respectively. Significantly higher grade 3/4 acute toxicity in terms of dysphagia was observed following cisplatin-based RCTX (p = 0.002). In multivariable analysis, females and patients with early primary tumors (T1-2) have longer EFS and OS, regardless the CTX regimen.

CONCLUSIONS

Primary or adjuvant RCXT with CarboTaxol is a safe and effective treatment alternative for LASCCHN patients with contraindication to cisplatin-based RCTX.

Overexpression of PIK3CA in head and neck squamous cell carcinoma is associated with poor outcome and activation of the YAP pathway

OBJECTIVES

Phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) is commonly altered in many human tumors, leading to the activation of p110α enzymatic activity that stimulates growth factor-independent cell growth. PIK3CA alterations such as mutation, gene amplification and overexpression are common in head and neck squamous cell carcinoma (HNSCC) and. We aim to explore how these alterations and clinical outcome are associated, as well as the molecular mechanisms involved.

MATERIAL AND METHODS

Mutation and copy-number variation in PIK3CA, and whole-genome expression profiles, were analyzed in primary HNSCC tumors from The Cancer Genome Atlas (TCGA) cohort (n = 243). The results were validated in an independent cohort form the University Hospital of A Coruña (UHAC, n = 62). Expression of the PIK3CA gene protein product (PI3K p110α) and nuclear YAP were assessed in tissue microarrays in a cohort from the University Hospital 12 de Octubre (UH12O, n = 91).

RESULTS

Only high expression of the PIK3CA gene was associated with poor clinical outcome. The study of gene expression, transcription factor and protein signatures suggested that the activation of the Hippo-YAP pathway, involved in organ size, stem cell maintenance and tumorigenesis, could underlie tumor progression in PI3KCA overexpressing tumors. Tissue arrays showed that PI3K p110α levels correlated with YAP nuclear localization in HNSCC tumors.

CONCLUSIONS

High expression of PIK3CA in HNSCC primary tumors identifies patients at high risk for recurrence. In these tumors, progression could rely on the Hippo-YAP pathway instead of the canonical Akt/mTOR pathway. This observation could have important implications in the therapeutic options for patients.

EGF receptor signaling, phosphorylation, ubiquitylation and endocytosis in tumors in vivo

Despite a well-established role for the epidermal growth factor receptor (EGFR) in tumorigenesis, EGFR activities and endocytosis in tumors in vivo have not been studied. We labeled endogenous EGFR with GFP by genome-editing of human oral squamous cell carcinoma cells, which were used to examine EGFR-GFP behavior in mouse tumor xenografts in vivo. Intravital multiphoton imaging, confocal imaging of cryosections and biochemical analysis revealed that localization and trafficking patterns, as well as levels of phosphorylation and ubiquitylation of EGFR in tumors in vivo closely resemble patterns and levels observed in the same cells treated with 20–200 pM EGF in vitro. Consistent with the prediction of low ligand concentrations in tumors, EGFR endocytosis was kinase-dependent and blocked by inhibitors of clathrin-mediated internalization; and EGFR activity was insensitive to Cbl overexpression. Collectively, our data suggest that a small pool of active EGFRs is sufficient to drive tumorigenesis by signaling primarily through the Ras-MAPK pathway.