Snail controls the mesenchymal phenotype and drives erlotinib resistance in oral epithelial and head and neck squamous cell carcinoma cells

OBJECTIVE

The presence of regional metastases in patients with head and neck squamous cell carcinoma (HNSCC) is a common and adverse event associated with poor prognosis. The authors' recent work on human HNSCC tissues underlies Snail's role as a molecular prognostic marker for HNSCC. Snail positivity is significantly predictive of poorly differentiated, lymphovascular invasive, and regionally metastatic tumors. Here, the authors investigate the capacity of Snail to drive epithelial-mesenchymal transition (EMT) in human oral epithelial cell lines and its ability to confer drug resistance.

STUDY DESIGN

Snail was overexpressed in HNSCC and oral epithelial cell lines. Anchorage independent growth assays, wound healing assays, invasion and migration assays, spheroid modeling, and cell survival assays were performed.

SETTING

Academic tertiary medical center.

SUBJECTS AND METHODS

Snail overexpressing HNSCC (OSC, Tu212, Tu686) and oral epithelial cell lines (HOK 16-B, OKF-6) were evaluated using assays for wound healing, invasion and migration, 3-dimensional growth, Western blot, and immunofluorescence.

RESULTS

The overexpression of Snail in human HNSCC and oral epithelial cell lines drives EMT. The transfection of Snail confers the expression of a mesenchymal molecular signature, including downregulation of the epithelial adherens, such as E-cadherin and β-catenin, and induction of mesenchymal markers. Snail-overexpressing cell lines demonstrate rapid growth in Anchorage-independent growth assays, a decreased capacity to form tight spheroids, an increased resistance to erlotinib, and an increased capacity for invasion.

CONCLUSION

Snail controls the mesenchymal phenotype and drives erlotinib resistance in HNSCC cells. Snail may prove to be a useful marker in predicting epidermal growth factor receptor inhibitor responsiveness.

Parotidectomy and neck dissection in the management of conjunctival melanoma: are they necessary?

OBJECTIVES/HYPOTHESIS

The objectives of this study were to review traditional techniques for the management of conjunctival melanoma and assess the need for parotidectomy and neck dissection in the management of conjunctival melanoma.

STUDY DESIGN

Retrospective review.

METHODS

This study was a retrospective review conducted in a tertiary academic medical center of patients diagnosed with conjunctival melanoma over a 20-year period

RESULTS

There were 39 patients diagnosed with conjunctival melanoma identified from January 1990 to December 2010. Follow-up varied from 2 to 201 months (median, 25 months). Of the patients, 16 (41%) had local recurrences at the primary site, two (13%) of whom later presented with parotid disease. One patient with parotid recurrence had a subsequent neck dissection for confirmed metastatic spread. No patient in this series had metastatic cervical disease without initial spread to the parotid. The probability of disease-free survival at 1, 2, and 5 years was 77%, 68%, and 50%, respectively. The probability of parotid free progression at 1, 2, and 5 years was 100%, 96%, and 90%, respectively.

CONCLUSIONS

Conjunctival melanoma is a rare malignancy traditionally managed with aggressive treatment to optimize local control. The role for staging parotidectomy with or without neck dissection has been heavily debated. Based on our review, parotidectomy only needs to be undertaken when high suspicion for metastatic spread is present, such as a palpable or radiographically evident mass. In addition, without documented parotid disease, neck dissection is not required.

John M. Neck Dissection for T1 Oral Tongue SCCA: The UCLA Experience

Objective: The study was carried out in order to 1) evaluate features that could identify patients having increased risks of regional recurrences, and 2) examine the prognostic and therapeutic implications of elective neck dissection among patients who presented with early-stage oral tongue squamous cell carcinoma with clinically negative neck (T1cN0).

Method: A retrospective chart review of oral tongue cancer at a single tertiary institution identified 123 patients with T1cN0 oral tongue squamous cell carcinoma who underwent surgical tumor extirpation with/without adjuvant radiation treatment and/or chemotherapy from 1990 through 2009. This database was used to identify characteristics that are associated with occult lymph node metastases and measurement of patient outcomes.

Results: Eighty-nine patients underwent elective neck dissection, of which 20 patient specimens (22%) were found to harbor occult metastatic disease. However, no significant differences were noted in the frequency of regional recurrence according to gender, age, tumor size, the presence of perineural invasion, or occult metastatic disease ( P = .70, .29, .54, .30, and .47, respectively). In addition, patients who underwent elective neck dissection experienced lower rate of regional recurrence, although this did not achieve a statistically significant level ( P = .52).

Conclusion: Clinical observation of the clinically negative neck is justifiable for early stage T1 oral tongue squamous cell carcinoma. Elective cervical lymphadenectomy offers no benefit in preventing regional recurrence when compared to clinical observation. Furthermore, neither patient factors nor intrinsic tumor features demonstrated any prognostic significance in the setting of early stage T1 oral tongue carcinoma.

Utility of multiple sampling in reducing variation of salivary interleukin-8 and interleukin-1β mRNA levels in healthy adults

BACKGROUND

Salivary mRNA biomarkers can exhibit significant variation over time. The purpose of this study was to investigate the pattern and magnitude of variation of salivary mRNA biomarkers and to explore the effect of performing replicate assays and multiple sampling on the dispersion of salivary biomarkers.

METHODS

Salivary interleukin-8 (IL-8) and interleukin-1β (IL-1β) mRNAs, developed as biomarkers for oral cancer detection, were selected and measured from 15 healthy subjects at 4 different time points on the same day.

RESULTS

Salivary IL-8 and IL-1β mRNA levels fluctuated randomly over time without predictable rhythm and showed higher within-subject biological variation than analytical variation. The dispersion of salivary IL-8 and IL-1β mRNAs was more effectively reduced by taking multiple saliva sample measurements than by performing replicative assays.

CONCLUSION

Taking multiple saliva samples can effectively reduce variation of salivary IL-8 and IL-1β mRNA levels in healthy adults.

A novel modular polymer platform for the treatment of head and neck squamous cell carcinoma in an animal model

OBJECTIVE

To evaluate the therapeutic efficacy of a novel modular polymer platform in the treatment of head and neck squamous cell carcinoma (HNSCC).

DESIGN

In vivo study.

SETTING

Academic research laboratory. Subjects and

METHODS

C3H/HeJ mice and SCID/beige mice were randomized to receive implantation of no polymer, plain polymer, plain polymer with local cisplatin injection, or cisplatin polymer. The 2 groups of mice implanted with cisplatin polymer or no polymer were further randomized to receive 4 Gy of external beam radiation for 4 days or no radiation. Tumor size was measured until the mice were humanely killed. At necropsy, the tumors were excised and weighed.

RESULTS

There was a significant reduction in tumor growth using this novel polymer platform. The cisplatin-secreting polymer effectively reduced human head and neck tumor growth in SCID mice by 17-fold and SCC VII/SF tumors in C3H/HeJ mice by more than 16-fold compared with the control, plain polymer, and plain polymer + intratumoral cisplatin injection groups (P = .01 for both). We also observed a statistically significant lower tumor weight in mice treated with cisplatin polymer and concomitant radiation compared with the radiation alone and control groups.

CONCLUSIONS

We demonstrate the efficacy of a novel polymer platform in delivering cisplatin to a partially resected SCC in a murine model. This polymer may represent a new therapeutic modality for patients with HNSCC. Once this polymer platform is optimized, we will plan for validation in the context of a prospective trial in patients with unresectable advanced or recurrent HNSCC.

Brachytherapy-mediated bone damage in a rat model investigating maxillary osteoradionecrosis

OBJECTIVES

To assess clinical and radiologic findings from targeted radiotherapy to the rat maxilla and to compare findings with a recently developed rat model of mandibular osteoradionecrosis (ORN).

DESIGN

A prospective, controlled animal study.

SUBJECTS

Ten male Sprague-Dawley rats were divided into an experimental group receiving catheter-assisted high-dose-rate brachytherapy (n = 6) and a control group with catheter-assisted sham therapy (n = 4).

INTERVENTIONS

The second left maxillary molar was extracted 1 week after radiation, and the maxilla was harvested 3 weeks after dental extraction.

MAIN OUTCOME MEASURE

We used a standardized method with micro-computed tomography to determine the ratio of bone volume to total volume of the dental extraction socket.

RESULTS

On the gross clinical examination, all rats had mucosal coverage of the dental extraction site, whereas only the brachytherapy group demonstrated scarring of the mucosa. The median bone volume to total volume was 0.21 for the brachytherapy group and 0.49 for the control group (P = .01).

CONCLUSIONS

Similar to the mandible, the maxilla is susceptible to radiogenic bone injury as demonstrated by the significant decrease in bone volume of the radiated dental extraction socket. Despite radiologic similarities to mandibular ORN in the rat model, the maxilla demonstrated a more benign clinical course with a complete absence of bone exposure. Differences in the maxillary bone and microenvironment of the maxilla compared with the mandible may explain the subclinical response to radiation and lower incidence of maxillary ORN seen in patients. This maxillary model can be combined with our high-dose-rate mandibular ORN model to investigate these differences and better understand ORN.

Prevalidation of salivary biomarkers for oral cancer detection

BACKGROUND

Oral cancer is the sixth most common cancer with a 5-year survival rate of approximately 60%. Presently, there are no scientifically credible early detection techniques beyond conventional clinical oral examination. The goal of this study is to validate whether the seven mRNAs and three proteins previously reported as biomarkers are capable of discriminating patients with oral squamous cell carcinomas (OSCC) from healthy subjects in independent cohorts and by a National Cancer Institute (NCI)-Early Detection Research Network (EDRN)-Biomarker Reference Laboratory (BRL).

METHODS

Three hundred and ninety-five subjects from five independent cohorts based on case controlled design were investigated by two independent laboratories, University of California, Los Angeles (Los Angeles, CA) discovery laboratory and NCI-EDRN-BRL.

RESULTS

Expression of all seven mRNA and three protein markers was increased in OSCC versus controls in all five cohorts. With respect to individual marker performance across the five cohorts, the increase in interleukin (IL)-8 and subcutaneous adipose tissue (SAT) was statistically significant and they remained top performers across different cohorts in terms of sensitivity and specificity. A previously identified multiple marker model showed an area under the receiver operating characteristic (ROC) curve for prediction of OSCC status ranging from 0.74 to 0.86 across the cohorts.

CONCLUSIONS

The validation of these biomarkers showed their feasibility in the discrimination of OSCCs from healthy controls. Established assay technologies are robust enough to perform independently. Individual cutoff values for each of these markers and for the combined predictive model need to be further defined in large clinical studies.

IMPACT

Salivary proteomic and transcriptomic biomarkers can discriminate oral cancer from control subjects.

John MA. Snail as a novel marker for regional metastasis in head and neck squamous cell carcinoma

OBJECTIVE

Previous studies have shown Snail expression integral to the epithelial-mesenchymal transition during tumor progression. However, its behavior in clinical head and neck squamous cell carcinomas (HNSCCs) is yet undefined. We therefore sought to (1) investigate clinical and histopathologic characteristics of Snail-positive HNSCC and (2) understand the link between Snail and other commonly used HNSCC tumor markers.

STUDY DESIGN

A retrospective case-control study was conducted.

SETTING

This study was conducted in a large-scale academic center.

STUDY SUBJECTS

Of 51 consecutive HNSCC, 42 surgical resections were included.

METHODS

Two separate pathologists performed standard histopathologic reviews along with immunohistochemistries (Snail, E-cadherin, p16, epidermal growth factor receptor [EGFR]) and in situ hybridization (human papilloma virus [HPV]). Medical review for all cases was performed.

RESULTS

Twenty-two (52%) of 42 cases stained 4+ Snail (>75% staining). The remaining 20 cases were considered negative. Snail was strongly inversely related to E-cadherin expression (ρ = -0.69, P < .001), but statistically independent from HPV, p16, or EGFR expression. Snail(+) tumors were equally represented from each anatomic subsite. Snail(+) tumors were strongly associated with poor differentiation (P < .001) and basaloid classification (P = .004). Snail(+) tumors were also strongly associated with lymphovascular invasion (P = .02), but not perineural invasion. Ultimately, 11 (50%) of 22 of Snail(+) tumors demonstrated positive nodal metastasis and 11 (79%) of 14 node-positive cases were Snail(+) (P = .02).

CONCLUSION

This pilot study provides promising evidence of Snail' role as a molecular prognostic marker for HNSCC. Snail positivity is significantly predictive of poorly differentiated, lymphovascular invasive, as well as regionally metastatic tumors. Because Snail positivity appears independent of HPV, p16, and EGFR expression, Snail may prove to improve upon these markers' predictive limitations.

Standardized analysis of mandibular osteoradionecrosis in a rat model

OBJECTIVE

To develop a rat model of mandibular osteoradionecrosis(ORN) that uses novel micro-computed tomography bone volume analysis and detailed histology to provide a more effective, quantifiable, and standardized way to study ORN in vivo.

STUDY DESIGN

Animal model.

SETTING

Academic medical center.

SUBJECTS AND METHODS

Modifications to our previously published rat model of mandibular ORN were done to develop an ideal protocol consisting of 10 rats (6 experimental and 4 controls) with their left middle mandibular molar removed 7 days after either 20 Gy high dose rate brachytherapy or sham irradiation. Rats were sacrificed 21 days after extraction for landmark defined bone volume and histologic analysis.

RESULTS

A standardized method of quantification was achieved in all samples. The radiated group (XRT) had a mean bone volume/total volume (BV/TV) of 13.8% compared to 65.9% for controls (P < .001). There were increases in osteoclasts and fibrosis, decreases in osteoblasts,and less bone in radiated samples with a mean (SD)of 5.91 (3.77) osteoclasts/high-powered field (HPF) and 4.00(1.83) osteoblasts/HPF in XRT samples compared to 1.08(1.08) osteoclasts/HPF and 22.49 (6.00) osteoblasts/HPF for controls (P <.001).

CONCLUSION

Our updated model continues to be clinically analogous to human mandibular ORN and improves the radiologic and histologic analysis of bony defects, providing a method for quantification of bone loss. Further cell-specific staining, including immunohistochemistry, can be used with this model to study potential cellular mechanisms of mandibular ORN and test any future therapeutic options.

John M. Snail Drives Erlotinib Resistance in Head and Neck Squamous Cell Carcinoma Cells

Objective: Snail positivity is predictive of poorly differentiated, invasive, and regionally metastatic HNSCC tumors. We have demonstrated the role of Snail in the inflammation-induced promotion of EMT. Here, we investigate the capacity of Snail to drive EMT in human oral epithelial cell lines, and its ability to confer drug resistance.

Method: Snail was overexpressed in HOK and OKF oral epithelial cell lines. AIG assays, wound healing assays, invasion and migration assays, spheroid modeling, and drug resistance assays were performed. Differential gene expression between Snail-overexpressing and control epithelial and tumor cell lines was evaluated using gene expression microarray analysis.

Results: The overexpression of Snail in human oral epithelial cell lines (HOK, OKF) drives EMT. OKF-Snail and HOK-Snail lines demonstrate growth in anchorage-independent growth assays; a decreased capacity to form tight spheroids; increased resistance to erlotinib; and a highly invasive and migratory nature. Gene expression analysis also revealed Snail-associated differential gene expression with the potential to affect inflammatory cytokine regulation, migration, invasion, and diverse aspects of HNSCC progression.

Conclusion: Snail controls the mesenchymal phenotype and drives erlotinib resistance in HNSCC cells. Snail may prove to be a useful marker in predicting EGFR inhibitor responsiveness.

Magnetic resonance imaging-guided fine needle aspiration for the diagnosis of skull base lesions

Magnetic resonance imaging (MRI)-guided fine needle aspiration was used to obtain tissue from lesions of the skull base for cytologic diagnoses in 14 patients. Our technique utilized a guiding system to enable three-dimensional orientation in a two-dimensional scan and a high nickel content 22 gauge needle to minimize significantly MRI artifact. Needle access to the skull base was provided through a subzygomatic or retromandibular approach. In seven of nine cases an accurate diagnosis was established by this technique and later confirmed by surgical exploration and histologic analysis. Failure to obtain a representative specimen from the lesion occurred in one case and difficulty in interpreting the cytologic features of the tissue was encountered in another case. The indications, limitations, and technical details of the procedure are described.

Transnasal, transfacial, anterior skull base resection of olfactory neuroblastoma

PURPOSE

Using a transnasal, transfacial, anterior skull base approach, we have removed olfactory neuroblastomas (OFN) obviating the need for a frontal craniotomy. The objectives were to present our surgical approach in achieving clear margins, to assess patient survival, and to recommend eligibility criteria.

MATERIALS AND METHODS

A retrospective chart review was done to identify patients diagnosed with OFN who underwent this surgical approach. Thirteen patients were identified who underwent our pictorially described approach. Postoperative assessment of pathologic margins, patient survival, and limitations of surgical approach was determined.

RESULTS

Of the 13 patients, 12 (92%) had clear postsurgical margins. One patient had residual intracranial disease due to coagulopathy preventing further resection. Twelve patients remain alive with 10 patients remaining disease-free (follow-up ranging from 11 to 64 months). Three patients presented with recurrent disease initially, with 2 having had subsequent repeat local and regional recurrences, respectively; one of whom died recently of the re-recurrent disease. One patient had a postoperative cerebrospinal fluid leak repaired via the original surgical approach.

CONCLUSIONS

Although craniofacial resection remains an accepted approach for surgical treatment of OFN, we have adopted a transnasal, transfacial approach eliminating the need for a frontal craniotomy. This approach allows for adequate exposure of the cribriform plate, dura, and anterior skull base. Our technique minimizes dural defects and prevents many craniotomy-associated complications, including frontal lobe retraction. Long-term follow-up is needed to compare survival using this approach; however, our results to date are quite promising.

Animal model of radiogenic bone damage to study mandibular osteoradionecrosis

OBJECTIVE

The objective of the study was to create an animal model to study mandibular osteoradionecrosis (ORN) using high-dose rate (HDR) brachytherapy.

METHODS

Ten Sprague-Dawley male rats were used in this study. Six rats received a single dose of 30 Gy using an HDR remote afterloading machine via a brachytherapy catheter placed along the left hemimandible. The remaining 4 rats served as controls with catheter placement without radiation (sham). On the day following irradiation or sham, all 3 left mandibular molars were atraumatically extracted. Twenty-eight days after irradiation, mandibles were examined using nondecalcified histology with sequential fluorochrome labeling, decalcified histology, and micro-computed tomography scanning.

RESULTS

Irradiated rats demonstrated exposed bone at the extraction sockets, whereas the control animals had complete mucosalization. Alopecia was also seen in the irradiated group. Both histologic and radiologic analyses of the mandible specimens demonstrated a reduction in bone formation in the radiated mandibles as compared with controls.

CONCLUSIONS

Our HDR brachytherapy model incorporating postradiation dental extractions has successfully demonstrated reproducible radiogenic mandibular bone damage analogous to the clinical ORN. Although clinical criteria continue to be used today in describing ORN, this model can serve as a platform for future studies to define ORN and delineate its pathogenesis.

John M. Tonsillar Squamous Cell Carcinoma

Objective. To analyze outcomes in patients with squamous cell carcinoma (SCCA) of the tonsil from the years 1998 to 2006. To assess factors that may affect disease-specific survival, such as patient characteristics and/or treatment modality.

Study Design and Setting. National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) program.

Subjects and Methods. The SEER database was used to perform a population-based cohort analysis for patients diagnosed with SCCA of the tonsil from 1998 to 2006. Disease-specific survival was correlated with sex, age, ethnicity, year of diagnosis, and treatment modality in a univariate Cox proportional hazards analysis and a multiple Cox-regression model with and without interaction effect.

Results. Applied inclusion criteria resulted in 8378 patients. Of this patient cohort, 80% were male and 85% were white. The mean patient age at diagnosis was 58.1 years. On univariate and multivariate analyses, ethnicities other than white carried a significantly higher rate of disease-specific death (hazard ratio = 1.71, P < .001). Each additional year of age at the time of diagnosis carried approximately a 4% increase in likelihood of disease-specific death. With each passing year of time at diagnosis, patients carried a decreased risk of disease-specific death ( P < .001); this value was significant in all 3 statistical models. Patients who underwent external-beam radiation had a higher likelihood of disease-specific survival with each passing year at time of diagnosis.

Conclusion. Population analysis based on the SEER database reveals increased disease-specific survival from tonsillar SCCA in more recent years. This may be because of earlier diagnosis, an increase in less aggressive subtypes of SCCA, and more effective treatment modalities.