Abstract B35: Characterization of exosomes extracted from primary tumor samples of HPV+/- oropharyngeal cancer

Abstract

Abstract Objective: To determine if distinctions in exosomal cargo contribute to differences in EMT between HPV-related and HPV-unrelated oropharyngeal disease and can provide a signature for prediction of tumor aggressiveness and metastatic potential. Subjects and Methods: Specimen from patients with HPV+/- OPSCC were collected according to an IRB-approved protocol including primary tumor, lymph node metastasis, distant metastasis, and serum when available. Exosomes isolated from HPV+ and HPV- tumors were analyzed with miARma-seq and proteomics. These same exosomes were cocultured with well-characterized HPV+ and HPV- cell lines as well as fibroblasts and normal keratinocytes. Tumor aggressiveness, EMT, and potential for metastasis were measured utilizing wound healing scratch assays and transwell invasion assay techniques based on the Boyden Chamber migration assay. Confirmation of epithelial to mesenchymal transition was evaluated by Western blot and qPCR using a panel of well-established EMT markers (e-cadherin, n-cadherin, vimentin, snail, slug, twist, ZEB1/2). Results: Tumors from HPV+ patients demonstrate exosomal content enriched in EMT markers compared to HPV-negative patient cultures. Exosomes extracted from primary tumor and lymph node metastasis of the same patient demonstrate differential expression of markers of EMT. Exosomes extracted from lymph node and cocultured with fibroblasts demonstrate increased invasion and migration. Conclusions: Exosomes can be extracted from primary patient tumor cultures of both primary tumor and lymph node metastasis. These exosomes demonstrate differential expression of markers of EMT. Exosomal contents can be exploited for biomarker discovery to aide in prognostication. Citation Format: Vivian F. Wu, Xiang Guo Dai, Michael Chopp. Characterization of exosomes extracted from primary tumor samples of HPV+/- oropharyngeal cancer [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr B35.