Project summary/Abstract
The proposed studies focus on recurrent respiratory papillomatosis (RRP), a persistent human papillomavirus (HPV)-driven
disease that has significant morbidity yet no FDA-approved treatment options. As the most common benign neoplasm of
the larynx in children, RRP is caused by low risk strains of HPV, most commonly HPV6, and presents as recurring epithelial
papillomas along the respiratory tract that threaten the airway. Surgeries are non-curative; children undergo an average of
4-5 procedures to remove masses in the first year alone and can face hundreds in their lifetime. The clinical course of RRP
thus poses a severe burden as it is unpredictable and carries a risk of malignant conversion when it progresses to other
sites in the aerodigestive tract. Despite the use of an array of attempts at off-label adjuvant therapies, no single agent has
been effective at eliminating pediatric RRP, and we cannot predict which patients will respond to any particular drug or
treatment regimen. A deeper understanding of the viral and cellular drivers of disease is thus essential to identify better
therapies. To this end, single cell RNA sequencing (scRNAseq) was performed on RRP-N(ormal) matched specimens from
a treatment naïve patient and analysis performed to select candidate viral (HPV6 E5) and cellular (NOTCH signaling) drivers
for mechanistic interrogation.
Clinical progress in the RRP field has been hindered by the absence of authentic model systems to define and test predictive
biomarkers and key regulators of RRP development. Primary monolayer RRP cells from adults, but not children, are
reported in the literature. However, monolayer culture is not conducive to the study of HPV-driven disease as the HPV viral
life cycle requires 3D differentiated mucosa. Preliminary work in our laboratory establishes a pipeline of internally controlled,
patient-specific models of RRP consisting of RRP-N matched patient tissue cultured into 2D primary cells that have been
successfully engineered into 3D organotypic epithelial rafts. Tissue specimens and derivative primary cells from 23 patients
have been generated for use in the proposed studies. Validation of preliminary transcriptomic and scRNAseq data in 3D
organotypic rafts support the feasibility of using these models for the proposed translational studies to identify disease
biomarkers, drivers, and molecular targets of RRP. The project is supported out by a team of scientists with a history of
collaboration and complementary expertise in epithelial models, scRNAseq, omics methodologies, statistics and pathology,
as well as clinicians who care for one of the largest cohort of children and young adults with RRP in the USA.