G.T. Wolf

The tumor suppressor gene rap1GAP is silenced by miR-101-mediated EZH2 overexpression in invasive squamous cell carcinoma

Rap1GAP is a critical tumor suppressor gene that is downregulated in multiple aggressive cancers, such as head and neck squamous cell carcinoma, melanoma and pancreatic cancer. However, the mechanistic basis of rap1GAP downregulation in cancers is poorly understood. By employing an integrative approach, we demonstrate polycomb-mediated repression of rap1GAP that involves Enhancer of Zeste Homolog 2 (EZH2), a histone methyltransferase in head and neck cancers. We further demonstrate that the loss of miR-101 expression correlates with EZH2 upregulation, and the concomitant downregulation of rap1GAP in head and neck cancers. EZH2 represses rap1GAP by facilitating the trimethylation of histone 3 at lysine 27, a mark of gene repression, and also hypermethylation of rap1GAP promoter. These results provide a conceptual framework involving a microRNA–oncogene–tumor suppressor axis to understand head and neck cancer progression.

A novel approach to biomarker discovery in head and neck cancer using an autoantibody signature

Despite the dismal prognosis for patients with squamous cell carcinoma of the head and neck (SCCHN), there have been no novel treatments in over 40 years. Identification of novel tumor antigens in SCCHN will facilitate the identification of potential novel treatment targets. Tumor antigens are proteins selectively expressed by tumor cells and recognized by the host immune system. Phage-displayed tumor antigens were enriched by biopanning with normal and then SCCHN-specific serum. Ninety-six phage clones were sequenced for identification, and 21 clones were validated using Luminex. One of these proteins, L23, a novel tumor antigen in SCCHN, was validated as an oncogene. L23 is upregulated in SCCHN compared with normal keratinocytes. Knockdown of L23 inhibited proliferation, invasion and cell survival. Overexpression of L23 had the reverse effect. Overexpression of L23 in non malignant cells led to transformation. Injection of SCCHN cells with knockdown of L23 in mice, induced tumors that were significantly smaller than control tumors. In conclusion, the immunomic screen yielded a panel of antigens specific to SCCHN; one of these proteins, L23, is a novel oncogene in SCCHN.

Evaluation of CD44 variant expression in oral, head and neck squamous cell carcinomas using a triple approach and its clinical significance.

Cancer stem cells possess the qualities of self-renewal, tumorigenesis and the ability to recapitulate a heterogeneous tumor. Our group was the first to isolate head and neck squamous cell carcinoma (HNSCC) stem cells using the cell surface marker CD44. CD44 is a trans-membrane glycoprotein with a multitude of key-functions that regulate cancer cell proliferation and metastasis. The variety of CD44 functions is due to tissue-specific patterns of glycosylation of the extracellular portion, and to the multiple protein isoforms (CD44 variants, CD44v) generated by alternative splicing. This study investigates the expression pattern of CD44 variants in HNSCC. Ten cell lines from the most common HNSCC locations and representative of various clinical outcomes were assayed by quantitative real-time PCR, flow cytometry and immunofluorescence comparatively with normal oral keratinocytes. The CD44 v4 and v6 were exclusively abundant in HNSCC while the isoform v1,2 was expressed in normal oral keratinocytes. Of interest, the highest level of CD44v6 expression was detected in advanced metastatic HNSCC, suggesting a link between CD44v6 expression and HNSCC metastasis, while the highest CD44v4 was detected in a stage IV HNSCC refractory to chemotherapy which developed recurrence. Oral-derived HNSCC expressed the highest CD44v4 and v6, and levels corresponded with staging, showing also an increasing tendency with recurrence and metastasis. CD44v were detected predominantly in smaller cells (a characteristic that has been associated with stem cell properties) or cells with mesenchymal morphology (a characteristic that has been associated with the migratory and invasive potential of epithelial tumor cells), suggesting that CD44v differential expression in HNSCC may be representative of the morphological changes inherent during tumor progression towards a more aggressive potential, and thus contributing to the individual tumor biology. The mechanism of CD44 variant involvement in HNSCC progression and metastasis is under investigation.

In silico modeling of the molecular interactions of antacid medication with the endothelium: novel therapeutic implications in head and neck carcinomas.

Pathological acid reflux is a common event in patients afflicted with head and neck squamous cell carcinomas (HNSCCs), known to play a role in HNSCC etiology and contribute to complications after surgery or during radiation and chemotherapy. Antacid medications are commonly prescribed in HNSCC patients as part of their cancer treatment, and consist of two classes: histamine 2 receptor antagonist class (H2RA, with cimetidine as its prototypical drug) and proton pump inhibitors class (PPI, with omeprazole as its prototypical drug). Clinical evidence revealed a significant survival benefit of antacid usage in a large cohort of HNSCC patients treated in our Otolaryngology Department, with a median follow-up of over 5 years. Therefore, we postulate that one mechanism by which antacid intake enhances patient survival could involve modulation of tumor cell adhesion to endothelium, critical in the initiation of the metastatic dissemination. This study investigates the potential physical interactions between cimetidine and omeprazole with the endothelial E-selectin (E-sel) and its ligand sialyl Lewis X (sLex) using a molecular visualization energy-based program (AutoDock). Docking results were further analyzed with the PyMOL program, which allowed for measurements of the distances between the drugs and the closest interacting atoms or residues on E-sel and sLex molecules. Our model predicts that omeprazole displays a stronger interaction with E-sel than cimetidine, as extrapolated from the calculated overall binding energies. However, the shorter distances existing between interacting atoms in the proposed E-sel/cimetidine complex are suggestive of more stable interactions. Neither antacid/E-sel complex overcame the stronger Autodock-calculated sLex/E-sel interaction, suggesting competitive inhibition was not involved. This study provides the first in silico evidence of omeprazole and cimetidine ability to bind to adhesion molecules involved in tumor dissemination, underlining their therapeutic potential in the HNSCC clinical management.

Tristetraprolin regulates IL-6 which is correlated with tumor progression in head and neck squamous cell carcinoma

Tumor‐derived cytokines play a significant role in the progression of head and neck squamous cell carcinoma (HNSCC). Targeting proteins, such as tristetraprolin (TTP), that regulate multiple inflammatory cytokines may inhibit the progression of HNSCC. However, TTPs role in cancer is poorly understood. The goal of the current study was to determine whether TTP regulates inflammatory cytokines in patients with HNSCC.

Salvage Surgery for Squamous Cell Carcinoma of the Head and Neck in the Era of Immunotherapy: Is It Time to Clarify Our Guidelines?

Treatment for recurrent squamous cell carcinoma of the head and neck (SCCHN) remains a challenge, and the disease carries a significant burden for patients and their families. Although the overall survival of patients with locally advanced SCCHN has improved with the addition of platinum-based chemotherapy to definitive radiation, significant numbers of patients continue to have recurrent disease. It is estimated that 30% to 40% of patients treated with definitive therapy will experience recurrence, with the majority of recurrences occurring locoregionally. Patients with recurrent disease are faced with few curative options and are desperate for modalities that will prolong their life expectancy while preserving key functions and quality of life. Although salvage surgery (SS) has been advocated as the modality of choice to achieve these goals, its indications remain poorly defined, with a significant risk of complications of up to 67%. It is clear that although patients may benefit from SS, the outcomes for a number of those who are offered this modality remain poor. Even though age and performance status are important predictors of patient outcomes, clear guidelines determining eligibility are lacking. SS has not been compared directly with re-irradiation because of the obvious challenges in implementing such a trial and because of the difficulty in interpreting nonrandomized data on account of the lack of uniformity and inherent selection biases. In the locally recurrent and metastatic setting, we witnessed improvements with the addition of cetuximab to the platinum backbone, and this led to the adoption of the EXTREME (platinum, 5FU and Cetuximab) regimen as a new standard of care a decade or so ago; however, despite these advances, practices and recommendations for SS continued to be untested. In that respect, it is noteworthy that patients are enrolled into systemic therapy trials often based on the exclusion of SS, and this introduces an inherent bias that renders retrospective comparisons impossible to perform. Because immunotherapy has recently evolved in a relatively short time into a new standard for patients with advanced, incurable, heavily pretreated SCCHN, with 2 immune checkpoint inhibitors (ICPIs) approved in 2016, we believe that it is time to look at our long-held practices in a new light. Historically, although induction chemotherapy has failed to produce significant improvements in patient survival, preoperative single doses of ICPIs have produced impressive responses with little toxicity in different tumor types, including SCCHN. Chemoresponders consistently show improved survival and increased responses to subsequent radiation. It is also significant that bioselection with induction chemotherapy has achieved impressive cure rates for laryngeal cancers. Although the picture remains unclear as far as the best way to use ICPIs in the definitive setting, there is every reason to believe that the standard of care for locally advanced SCCHN will soon change. Because a single-agent ICPI can result in long-term progression-free and overall survival for some heavily pretreated patients, it is legitimate to ask whether combination ICPI approaches could result in this much desired outcome for at least a percentage of patients currently offered SS who continue to fare poorly despite aggressive surgery. A plausible innovative strategy here would be induction immunotherapy for bioselection and

Intensity-modulated chemoradiotherapy aiming to reduce dysphagia in patients with oropharyngeal cancer: Clinical and functional results

The present study evaluated, both clinically and with fiberoptic endoscopic evaluation of swallowing (FEES), oral feeding volume, swallowing physiology, and aspiration risk in infants with Robin sequence treated exclusively with nasopharyngeal intubation (NPI) and specific feeding facilitation techniques (FFT). Eleven infants younger than 2 months participated. Criteria for NPI included recurrent crises of pallor and/or cyanosis and/or apnea and oxygen saturation less than 90%. The following FFT were used throughout the study period: use of a pacifier and massage to relax and move the tongue forward prior to feeding if the infant exhibited severe lingual retroposition (n = 11); manual support to maintain mandibular stability due to severe micrognathia (n = 1); both a long and a short nipple with a 1-mm-diameter enlarged hole (n = 9); nipple placement precisely on the tongue during suction (n = 11); rhythmic movement of the nipple in the mouth during sucking (n = 6); manual support of the cheek to facilitate lip closure (n = 3); and thickened liquids (n = 9). NPI improved the respiratory status of all infants which resulted in consistent improvement in oral feeding capacity and uniform weight gain. FEES was both well tolerated and useful in determining dysphagia and aspiration status throughout the study period.