Impact of the spheroid model complexity on drug response

Abstract

Pharmaceutical investigators are searching for preclinical models closely resembling the original cancer and predicting clinical outcome. This study compares drug response of three in vitro 3D-drug screening models with different complexity. Tumor cell line spheroids were generated from the cell lines Caco-2, DLD-1, COLO 205, HT-29 and HCT-116, and treated with clinically relevant combination therapies, namely 5-FU/oxaliplatin (FO), 5-FU/irinotecan (FI) and the molecular drugs Cetuximab, Trastuzumab, Vorinostat and Everolimus. Treatment results were compared with spheroids originated from tumor cell lines (Caco-2, DLD-1) co-cultured with stromal cells (PBMCs, cancer-associated fibroblasts of colorectal origin) and spheroids directly prepared from colon cancer tissues. Different microenvironment compositions altered the tumor cell line spheroid response patterns. Adding PBMCs increased resistance to FO treatment by 10-15% in Caco-2 and DLD-1 spheroids but decreased resistance to FI by 16% in DLD-1 spheroids. Fibroblast co-cultures decreased resistance to FI in Caco-2 spheroids by 38% but had no impact on FO. Treatment of colon cancer tissue spheroids revealed three distinct response pattern subgroups not detectable in 3D cell lines models. The cancer tissue spheroid model mimics both tumor characteristics and the stromal microenvironment and therefore is an invaluable screening model for pharmaceutical drug development.

Cell spheroids: the new frontiers in in vitro models for cancer drug validation

“…M a n u s c r i p t M a n u s c r i p t M a n u s c r i p t M a n u s c r i p t [11]. Pharmacy LMU represents the Pharmacy of the University Hospital of the LudwigMaximilian-University of Munich.…”

“…Developing 3D spheroid models of different complexity regarding cellular origin and composition can be utilized to evaluate the impact of clinically relevant drug combination therapies [11,51]. The development of multicellular tumor spheroid (MCTS) models is anticipated to increase the forecast data, decrease the animal testing, improve the efficiency of the cultured cells and reduce the time and cost to identify new drugs [52].…”

“…As stated previously, a solid tumor is not only composed of mutated cancer cells but of various cell types residing in a microenvironment with specific physicochemical, mechanical and biochemical features [39]. Although a 3D cancer cell system cannot recapitulate the genetic heterogeneity found in tumors, modeling cellular heterogeneity can be performed with heterotypic (Table 1), indicate different patterns in the tumor cell spheroid response [11]. Also, different methods in culturing conditions of cell spheroids can affect their drug resistance.…”

“…A c c e p t e d M a n u s c r i p t 11 To improve the distribution of therapeutics in 3D multicellular tumor spheroids, it is crucial to investigate the drug penetration properties and identification of metabolites with spatial specificity. Combining serial trypsinization and nanoflow LC-MS/MS, irinotecan and its bioactive metabolite were validated in distinct spatial regions of HCT-116 spheroids [61].…”

“…Also, in vivo animal models utilized as cancer models in the investigation of different human tumor types, such as zebrafish [8,9] that enable appropriate in vivo imaging and fast development, or humanized mouse models that have been shown promise [10], there are still limitations because zebrafish cannot accurately resemble a mammalian model and mouse biology does not present an appropriately authentic model of human tumors and is cost-inefficient when large numbers of animals are required [11]. Despite the significant increase on the development of novel anticancer treatments, patient survival rates have only marginally improved.…”