Dados do Resumo

Título

Cancer stem cells: devopment of an enriched model for drug screening in colorectal cancer

Introdução

Colorectal cancer (CRC) is the second leading cause of cancer deaths worldwide. Despite recent advances, this neoplasm presents therapeutic resistance and high relapse rates which can be attributable to the presence of cancer stem cells (CSCs). Therefore, it is crucial to target such a population with new therapeutic strategies such as drug repositioning, which consists of testing drugs already approved for clinical use in other diseases that may have antitumor effects.

Objetivo

This study aimed to test the effect of repositioned drugs in a CSC-enriched 3D cell culture model of CRC in comparison with its 2D counterpart.

Métodos

For CSC enrichment, HT29 adenocarcinoma colorectal cells were plated in ultra-low attachment flasks with CSC medium for 12 weeks, with periodic selection and splitting. CSC selection was confirmed using Fluorescence-activated cell sorting (FACS) and functional assays including Extreme Limiting Dilution Assay (ELDA) and Sphere formation assay (SFA). Individual spheroids were treated with standard-of-care and 4 drug candidates. The cell response was assessed using the CellTiter-Glo (ATP), Live/Dead cell staining, and CyQUANT (DNA). ELDA and SFA were used as endpoints for anti-CSC activity.

Resultados

The CSC-enriched model showed enhanced stemness compared to 2D through both functional assays and FACS. All tested drugs inhibited cell viability in a dose-dependent manner. Notably, the inhibitory concentration (IC50) values obtained for most treatments in 2D were lower than those obtained from CSC-like spheres. Both parental 2D and 3D CSC-like HT29 cells exhibited reduced viability with increasing concentrations of the tested drugs. One of the candidates IC50 was much lower in the 3D model than in the 2D. Furthermore, the differences observed among different evaluation methods suggest mechanistic variations in the effect of drugs.

Conclusões

Cancer stem cells, in the 3D model developed in this study, presented more resistance to the standard-of-care drug and to 3 candidate drugs. Although cells in 3D were sensitive to most of the drugs, the IC50 was higher than in 2D. However, one of the candidate drugs inhibited stemness and viability with a much lower concentration in 3D than in 2D, which warrants further investigation of it's activity using in vivo models aimed to eliminate cancer stem cells.

Financiador do resumo

Royal Free Charity; Faperj

Palavras Chave

cancer stem cells; drug screening; 3D culture