Abstract 2009: Culturing colorectal cancer cell lines in 3D spheroid cultures drives their cytokine profile towards a pro-inflammatory, tumorigenic and highly metastatic phenotype
Authors: Bersano Jacqueline , Schaich Katharina , Lashuk Kanstantsin , Schüler Julia 
Published: July 2021

Abstract
Colorectal cancer (CRC) is one of the most frequent cancers accounting for 12% of all deaths from cancer in Europe (2016). Furthermore, CRC patients are prone to develop metastases and have a poor prognosis underpinning the need for new targeted and broadly applicable therapeutic strategies. Tumor cell secretion contributes to hallmarks of cancer e.g. hyperproliferation, evasion of growth suppression and resistance to cell death. Dysregulated secretion is thus a driver of cancer progression and therefore holds promise as a general therapeutic target for the treatment of cancers. The overall aim of this study is to gain a quantitative understanding of the cancer secretome on a systems level to elucidate the influence of the microenvironment on selected players and vice versa the influence of the secretome in vitro and later on in vivo. In a first attempt to elucidate the role of secreted factors in colon cancer progression, we cultured 20 CRC cell lines (five PDX derived and 15 commercial lines) in 3D spheroid cultures and compared the secreted cytokine profile with the 2D culture conditions of the same CRC cell line panel. We analyzed 45 cytokines in duplicates by using a human specific magnetic bead-based assay. Of the 45 cytokines, 41 were detected at relevant levels in at least one cell line in either 2D or 3D. Four cytokines were exclusively secreted in a 3D setting: IFN alpha (tumorigenic), IL-17A (pro-inflammatory), TNF alpha (pro-inflammatory and tumorigenic) and VEGF-D (pro-metastatic). Every cell line displayed a distinct cytokine profile depending on the culture conditions. 13 lines showed more cytokines upregulated in 3D, four lines displayed more cytokines upregulated in 2D and 3 lines exhibited an equal number of cytokines up-regulated in the two culture conditions. Eleven cytokines were specifically higher secreted when the cells were cultured in 3D across the majority of the 20 cell lines. Most of them with pro-inflammatory, pro-angiogenic and tumorigenic capabilities. A cluster analysis helped to identify four clusters, two comprising mainly 3D cultured cell line and two primarily consisting of 2D datasets. The main discriminators for these four clusters were the secretion levels of VEGF-A, IL-1Ralpha and HGF. The thorough characterization of the secretome in different in vitro conditions revealed the influence of the tumor microenvironment on basic tumor characteristics like proliferation and invasiveness. Based on this data set we gained a quantitative understanding of the cancer secretome on a systems level. From here on we will further elucidate the influence of the microenvironment on selected players of the secretome and vice versa the influence of the secretome on tumor biology in vitro and later on in vivo.
Citation Format: Jacqueline Bersano, Katharina Schaich, Kanstantsin Lashuk, Julia Schüler. Culturing colorectal cancer cell lines in 3D spheroid cultures drives their cytokine profile towards a pro-inflammatory, tumorigenic and highly metastatic phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2009.