Abstract 1096: Engineering a cisplatin-resistant lung cancer microenvironment to model recurrence of aggressive tumors following first line cytotoxic therapy
Authors: Ahmad Omar M. , Olsen Elisabet A. , Carlino Delia A. , Byrne Charles E. , Mondrinos Mark 
Published: June 2022

Abstract
Aggressive lung cancers such as non-small cell lung carcinomas (NSCLC) commonly recur following first line therapy. Recurring tumors metastasize more rapidly. We hypothesize that drug-resistant phenotypes created by the selection pressure of first line treatments such as platinum-based cytotoxic agents contribute to the increased aggressivity of recurring NSCLC. We showed previously that an engineered model of cisplatin-resistant NSCLC tissues secretes more inflammatory cytokines compared to untreated controls and induces more severe muscle tissue injury in a microphysiological model of cachexia processes. Here, we report methods for the systematic generation of cisplatin-resistant A549 lung adenocarcinoma cell cultures and demonstrate their increased aggressivity in 3D spheroid culture and in 3D organotypic culture with patient-derived lung cancer-associated fibroblasts (CAF). We treated A549 cells with cisplatin for 96 hours at doses of 15-45µM, yielding cultures of 54.8-8.9% surviving cells as quantified via flow cytometric of cell size and permeability. Here we report characterization of spheroids and tissues composed of cells selected for resistance with 25 µM cisplatin (Cis-R) compared with untreated parent A549. This dose was selected because we were unable to recover proliferating cultures with lower percentages of surviving. Cis-R spheroids exhibited a significant reduction in circularity that is indicative of increased asymmetry. We measured a Ki67 index of 6.4 +/- 1.4% for parent A549 spheroids and 49.7 +/- 9.5% for Cis-R spheroids. The marked increase in cell proliferation of CisR spheroids correlated with increased distances of invasion and more mesenchymal-like cell morphologies of invading cells in 3D cultures of Cis-R spheroids without CAF. These data suggest that cisplatin resistant A549 created using our protocol are more proliferative and invasive in 3D culture environments due to cell intrinsic changes. Organotypic 3D cultures of Cis-R spheroids and CAF exhibited an increased density and alignment of myofibroblast-like CAF with smooth muscle actin cytoskeleton when compared to cultures of parent spheroids with the same CAF. Our results demonstrate proof of principle for modeling recurrent tumors with more aggressive phenotypes using this approach. Future experiments will translate these methods to patient-derived cultures and test the hypothesis that cisplatin-resistant recurrent NSCLC stimulates more severe local and distant stromal reactions as a driver of metastasis. Engineering validated models of drug-resistant recurring cancers will help accelerate the discovery of anti-metastasis therapies in human cell-based microphysiological systems.
Citation Format: Omar M. Ahmad, Elisabet A. Olsen, Delia A. Carlino, Charles E. Byrne, Mark Mondrinos. Engineering a cisplatin-resistant lung cancer microenvironment to model recurrence of aggressive tumors following first line cytotoxic therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1096.