Abstract A213: Three-dimensional tumor growth assay for patient-derived tissue and cell line models incorporating stromal elements for screening
Authors: Jiang Simon , Wrigley Jane , Malhi Sumanjeet , Wood Jamie , Morton Stephanie , Wainwright Louise , Harris Lucy , King Jason , Yin Yinfei , Kumari Rajendra 
Published: August 2018

Background: Preclinical in vitro and in vivo tumor models lack human stromal cells and are inadequate for the assessment of novel tumor microenvironment-targeted therapies. Here we report on a 3D-tumor growth assay (3D-TGA) in which patient-derived tumor cells are admixed with a basement membrane extract and bone marrow-derived mesenchymal stem cells (bmMSCs) in a 96-well format for screening. Response to standard-of-care (SoC) agents such as paclitaxel, targeted agents such as erlotinib were compared to subcutaneous xenograft responses in vivo. Methods: Tumor cells or xenograft materialthat is disaggregated to yield a pure epithelial population are admixed and suspended in basement membrane extract (Cultrex, Trevigen) with and without bmMSCs. Cells were maintained for three days before they were treated with a panel of test agents, such as paclitaxel, AZD2014, erlotinib, and carboplatin, and final cell viability was determined on day 7 by alamarBlue assay. IC50 curves were determined using GraphPad Prism 6.0. Subcutaneous tumor growth was evaluated three times a week by measuring the tumor in two dimensions using electronic calipers for the duration of the study, and tumor volumes were estimated. Treatment was initiated when tumor growth was established. Results: A panel of squamous NSCLC PDX models that contain various mutation sites (e.g., EGFR, KRAS) was assessed with a range of SoC (e.g., carboplatin, pemetrexed, and paclitaxel) or targeted agents (e.g., erlotinib, AZ2014). A squamous NSCLC model LU6422,that harbors a heterozygous mutation in the EGF-R intracellular kinase domain (c.2573T&gt;G (L858R)) showed exquisite sensitivity to erlotinib in both 3D TGA and xenograft studies. Similarly, a squamous NSCLC model LU6402 was assessed with AZD2014 and paclitaxel in 3D-TGA in the presence of bmMSCs, which showed an additive effect of AZD2014 in combination of paclitaxel on tumor cell growth. A similar efficacy was observed in subcutaneous in vivo xenograft; however, a combination finding was not evident when the stromal cells bmMSCs were absent. The data illustrate that the comparable sensitivities to various test agents between 3D-TGA and in vivo xenograft studies were observed. Conclusions: The 3D tumor growth assay restores the interaction between the tumor and stroma in a 96-well format enabling screening to multiple dug concentrations and combinations in a 7-day assay. This assay provides a unique opportunity for interrogating therapies that target the tumor microenvironment.

Citation Format: Simon Jiang, Jane Wrigley, Sumanjeet Malhi, Jamie Wood, Stephanie Morton, Louise Wainwright, Lucy Harris, Jason King, Yinfei Yin, Rajendra Kumari. Three-dimensional tumor growth assay for patient-derived tissue and cell line models incorporating stromal elements for screening [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A213.