P2.03b-070 Establishment of Organoid Cell Lines from Lung Squamous Cell Carcinoma: Topic: Biomarkers

Abstract

The limited number of available lung squamous cell carcinoma (LUSC) cell lines poses significant challenge for biological, experimental therapeutic and biomarker research in LUSC. Novel approaches to establish new preclinical models are urgently needed. We have previously established patient-derived xenografts (PDX) from resected tumors of LUSC patients and characterized them on the genomic, transcriptomic, and proteomic levels. We have used these PDX models to develop a method for establishment of 3D organoid cultures and cell lines as new in vitro preclinical models of LUSC. PDX models were established and propagated from resected primary non-small cell lung cancer (NSCLC) in NOD/SCID mice; they were molecularly profiled by exome sequencing, SNP array for copy number analysis, and immunohistochemistry (IHC). PDX tissue harvested from mice was dissociated into single cells and plated in 100% matrigel dome, with overlaying media on top. Organoids were characterized by H&E, and IHC of p63, CK5/6, TTF-1, and CK7. Organoid growth rate and drug screening were assessed using Celltiter glo cell viability assay. A total of 17 LUSC PDX models have been used for this study. All organoids were able to initiate in culture at passage 1, and the organoid establishment rate (beyond passage 4) is 50% (6/12). 4/12 (33%) LUSC organoids were able to be propagated beyond 10 passages for over 60 days with an average doubling rate of 2-3 days. Organoid tumor cells recapitulated the histological features of LUSC and were positive for p63 and CK5/6, and negative for TTF-1 and CK7 by IHC. Molecular characterization of LUSC PDX models revealed PIK3CA mutations, amplifications, and PTEN loss. Over 40% (4/9) of PI3K altered LUSC organoids were sensitive to PI3K inhibitor BKM120. LUSC organoids can be established for long term culture and recapitulate the phenotypic features of the PDX. The culture protocol is currently being tested on primary patient LUSC tumors. Organoid cultures and cell lines may be useful as additional preclinical models for functional validation of novel therapeutic targets in LUSC.