Abstract A034: 3D in-vitro model picturing cancer-stromal cell crosstalk & bone metastasis

Abstract

Abstract Breast cancer is presently the most prevalent malignancy and the second leading cause of tumor-related deaths among women. Approximately 75% of patients with advanced breast cancer will develop bone metastasis. Despite the significant improvement in treating primary breast cancer, the 5-year survival rate for metastatic breast cancer remains at 25%. While we recognize the critical importance of cancer cells and Tumor Microenvironment (TME) communication, the field still suffers from a lack of a proper model system to reconstitute 3D multi-cellular TME in-vitro, especially for bone metastasis. Most of the current 3D in-vitro breast cancer models are composed of cancer cells only and are unable to mimic the complex cellular homeostasis within the TME. To address this deficiency along with the tumor heterogeneity, we aimed to develop a unique 3D multi-cellular culture system using patient-derived (PD) cancer cells. In this study, we implemented the “hanging drop” method to create 3D Tumor Spheroids (TSs). This method was not only sufficient to build the 3D structure, but also significantly enhanced patient-derived cancer cell line establishment rate up to 75%. 3D TSs maintained their histopathological characteristics and original hormone receptor status. Over time, TSs exhibited intratumoral hypoxia leading to significant induction of VEGF expression and EMT showcasing the quality of the system. To investigate the complex interrelation between the tumor and TME, we cultured TSs with Endothelial Cells (ECs) and pericytes to introduce the vascular component. To probe these tumor-stromal interactions, we incorporated Cancer-Associated Fibroblasts (CAFs) into TSs and observed the successful growth of Multi-Cellular Tumor Spheroids (MCTSs) alongside the tubular structure. Analysis of our data revealed that the presence of stromal cells in TME enhanced tumor survival. In this study, we define how CAFs aid in the formation of vascular structures of ECs. Recent studies also have found that the effects of CAFs are significantly high in aggressive TNBC and HER2+ cell lines compared to HR+. The long-term goal of this current study is to explore bone-mimicking nano-clay-based 3D scaffold culture systems to investigate the development of metastatic tumors and to understand the influence of bone TME on cellular responses in-vitro. Citation Format: Shrinwanti Ghosh. 3D in-vitro model picturing cancer-stromal cell crosstalk & bone metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A034.