Faculty Bibliography

The epidermal growth factor receptor (EGFR) signaling pathway is frequently dysregulated in a variety of human malignancies. As a result, agents have been developed to selectively inhibit the tyrosine kinase function of EGFR (EGFR-TKI) for cancer therapy. However, the clinical efficacy of these drugs to date has been limited by both acquired and intrinsic resistance. Macroautophagy, a process of intracellular proteolysis, has been shown to be activated in response to EGFR targeted therapy. However, the specific role of the induction of autophagy remains controversial. Here we show that autophagy is induced in a dose-dependent manner by in vitro treatment of multiple cancer cell lines with EGFR-TKI. Additionally, we find that in cells highly resistant to EGFR-TKI, autophagy is not robustly activated and that co-treatment of these cells with rapamycin, a known inducer of autophagy, can partially restore sensitivity to EGFR-TKI. Finally, we demonstrate that, in resistant cell lines, EGFR-TKI sensitivity can be further inhibited by siRNA-mediated depletion of the critical autophagy protein ATG7. Thus, our data suggests that defective autophagy may be an EGFR-TKI resistance mechanism and that activation of autophagy may be a viable strategy to augment the cytotoxic effect of EGFR-TKIs.

OBJECTIVE:To show that sialoendoscopy is both a safe and effective alternative to traditional treatments for juvenile recurrent parotitis and sialolithiasis. DESIGN/METHODS:Retrospective medical chart review. SETTING/METHODS:Two major pediatric tertiary care centers. PATIENTS/METHODS:Eighteen pediatric patients. INTERVENTIONS/METHODS:A total of 33 sialendoscopic procedures on 27 glands. MAIN OUTCOME MEASURES/METHODS:Indications for surgery, age at onset of symptoms, age at procedure, sex, intraoperative findings, complications, recurrences, need for additional procedures, and follow-up interval. RESULTS:Juvenile recurrent parotitis was the most common indication for sialendoscopy (12 of 18) followed by sialolithiasis (4 of 18). Ten of 12 patients with juvenile recurrent parotitis were asymptomatic after 1 or 2 sialendoscopies (8 patients and 2 patients, respectively). There were 6 minor complications. Three patients ultimately required gland excision for disease management. CONCLUSION/CONCLUSIONS:Sialoendscopy is safe and effective as a treatment for pediatric salivary gland disorders.

The surgical robot has been demonstrated to have useful applications in urologic, gynecologic, cardiac, general, and endocrine surgery. The development of robotic surgery has enhanced the precision and control of the surgeon in minimally invasive surgical situations specific to these specialties and, more recently, has been applied to the treatment of oropharyngeal tumors in the form of transoral robotic surgery (TORS). The elimination of the need for lip- and mandible-splitting approaches has allowed a reassessment of surgical options for the treatment of tumors that have until recently been primarily addressed nonoperatively with chemoradiation. The TORS approach has created the need to adapt current reconstructive options to robotic technology to manage the resultant tissue defects and to assess and compare the effectiveness of these procedures. This report details our early experience with the use of robot-assisted free tissue transfer for management of soft tissue defects of the oropharynx.

UNLABELLED:Despite evidence implicating transcription factors, including STAT3, in oncogenesis, these proteins have been regarded as "undruggable." We developed a decoy targeting STAT3 and conducted a phase 0 trial. Expression levels of STAT3 target genes were decreased in head and neck cancers following injection with the STAT3 decoy compared with tumors receiving saline control. Decoys have not been amenable to systemic administration due to instability. To overcome this barrier, we linked the oligonucleotide strands using hexaethylene glycol spacers. This cyclic STAT3 decoy bound with high affinity to STAT3 protein, reduced cellular viability, and suppressed STAT3 target gene expression in cancer cells. Intravenous injection of the cyclic STAT3 decoy inhibited xenograft growth and downregulated STAT3 target genes in the tumors. These results provide the first demonstration of a successful strategy to inhibit tumor STAT3 signaling via systemic administration of a selective STAT3 inhibitor, thereby paving the way for broad clinical development. SIGNIFICANCE/CONCLUSIONS:This is the fi rst study of a STAT3-selective inhibitor in humans and the fi rst evidence that a transcription factor decoy can be modifi ed to enable systemic delivery. These findings have therapeutic implications beyond STAT3 to other “undruggable” targets in human cancers.

Frequent gene amplification of the receptor-activated calcium-dependent chloride channel TMEM16A (TAOS2 or ANO1) has been reported in several malignancies. However, its involvement in human tumorigenesis has not been previously studied. Here, we show a functional role for TMEM16A in tumor growth. We found TMEM16A overexpression in 80% of head and neck squamous cell carcinoma (SCCHN), which correlated with decreased overall survival in patients with SCCHN. TMEM16A overexpression significantly promoted anchorage-independent growth in vitro, and loss of TMEM16A resulted in inhibition of tumor growth both in vitro and in vivo. Mechanistically, TMEM16A-induced cancer cell proliferation and tumor growth were accompanied by an increase in extracellular signal-regulated kinase (ERK)1/2 activation and cyclin D1 induction. Pharmacologic inhibition of MEK/ERK and genetic inactivation of ERK1/2 (using siRNA and dominant-negative constructs) abrogated the growth effect of TMEM16A, indicating a role for mitogen-activated protein kinase (MAPK) activation in TMEM16A-mediated proliferation. In addition, a developmental small-molecule inhibitor of TMEM16A, T16A-inh01 (A01), abrogated tumor cell proliferation in vitro. Together, our findings provide a mechanistic analysis of the tumorigenic properties of TMEM16A, which represents a potentially novel therapeutic target. The development of small-molecule inhibitors against TMEM16A may be clinically relevant for treatment of human cancers, including SCCHN.

Anoctamin-1 (ANO1) (DOG1, TMEM16a) is a calcium-activated chloride channel initially described in gastrointestinal stromal tumors, but now known to be expressed in a variety of normal and tumor tissues including salivary tissue in murine models. We herein perform a comprehensive survey of DOG1 expression in 156 cases containing non-neoplastic human salivary tissues and tumors. ANO1 mRNA levels were significantly higher (8-fold increase, P<0.0001) in normal parotid tissue (n=6) as compared with squamous mucosa (n=15). By immunohistochemistry, DOG1 showed a diffuse moderate (2+) apical membranous staining pattern in normal serous acini, 1+ apical membranous pattern in mucous acini, and variable 1-2+ apical staining of distal intercalated ducts. Myoepithelial cells, striated and excretory ducts were invariably negative. All acinic cell carcinomas (n=28) were DOG1 positive demonstrating a complex mixture of intense (3+) apical membranous, cytoplasmic and complete membranous staining. Most ductal tumor types were negative or only showed a subset of positive cases. Within the biphasic tumor category, adenoid cystic carcinomas (18/24 cases) and epithelial-myoepithelial carcinomas (8/15 cases) were frequently positive, often showing a distinctive combined apical ductal and membranous/cytoplasmic myoepithelial staining profile. Thus, DOG1 staining is a marker of salivary acinar and to a lesser extent intercalated duct differentiation. Strong staining can be used to support the diagnosis of acinic cell carcinoma. DOG1 may also be a marker of a 'transformed' myoepithelial phenotype in a subset of biphasic salivary gland malignancies.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Parapharyngeal space (PS) tumors are surrounded by critical anatomical structures. Resection is often challenging due to limited surgical exposure. Herein, we report a novel transcervical, minimally invasive, video-assisted technique that facilitates the resection of PS lesions. STUDY DESIGN/METHODS:Case series and review of literature. METHODS:Description of surgical technique with analysis of four cases and literature review. RESULTS:The technique combines a transcervical approach to the PS and skull base with video-assisted and image-guided dissection of tumor. Four cases of benign PS tumors resected with this technique are reported. The size of the tumor excised varied between 0.9 cm and 5 cm. Estimated blood losses were minimal. The average length of hospital stay was 1.5 days. No permanent complications were encountered. CONCLUSIONS:Excision of PS tumor abutting the skull base using a novel minimally invasive, video-assisted, image-guided, transcervical approach is feasible and safe. The short hospitalization stay and low morbidity makes it well suited for the resection of benign PS lesions.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Organ preservation surgery is a major focus in head and neck oncology. Current approaches are aimed toward improving quality of life and decreasing treatment-related morbidity. Transoral robotic surgery was developed to overcome the limitations of traditional surgical approaches. The most widely used robotic system is the da Vinci Surgical System. Although the da Vinci offers clear surgical advantages over traditional approaches, its rigid operative arms prevent complex maneuverability in three-dimensional space. The ideal surgical robot would configure to the anatomy of the patient and maneuver in narrow spaces. We present the first cadaveric trials of the use of a highly flexible robot able to traverse the nonlinear upper aerodigestive tract and gain physical and visual access to important anatomical landmarks without laryngeal suspension. STUDY DESIGN/METHODS:Feasibility. METHODS:Using human cadavers, we investigated the feasibility of visualizing the endolarynx transorally with a highly flexible robot without performing suspension of the larynx. Two fresh and four preserved human specimens were used. RESULTS:Unhampered visualization of the endolarynx was achieved in all specimens without performing laryngeal suspension. Standard mouth retractors facilitated the delivery of the robot into the endolarynx. CONCLUSIONS:The flexible robot technology mitigates laryngeal suspension and the limitations of current robotic surgery with rigid line-of-sight-directed instruments. Having demonstrated the feasibility of physical and visual access to the endolarynx, future work will study the feasibility of using the highly flexible robot in transoral robotic procedures with flexible instrumentation placed in the robot's available working ports.