Genetic and transcriptomic alterations underlying aggressiveness in 5-fluorouracil-resistant HCT116 cells

Resistance to 5-fluorouracil (5-FU) remains an obstacle to effective colorectal cancer (CRC) treatment. Genetic alterations play significant roles in the development of drug-induced chemoresistance, leading to tumor recurrence and increased aggressiveness. This study sought to characterize the transcriptomic profiles of 5-FU-resistant CRC cells. HCT116 colon cancer cells were progressively exposed to increasing concentrations of 5-FU to induce resistance. Chemoresistance and aggressiveness were investigated using MTT, clonogenic, and scratch assays. Transcriptomic alterations were analyzed with next-generation sequencing (NGS). Our results revealed that 5-FU-resistant cells exhibited cross-resistance and enhanced invasive potential compared to parental HCT116 cells (HCT116-PT cells), characteristics that were associated with upregulation of matrix metalloproteinases (MMP-2 and MMP-9). Notably, we also observed significant overexpression of T cell immunoreceptor with Ig and ITIM domains (TIGIT) and cell adhesion-related genes, including neurexophilin and PC-esterase domain family member 1 (NXPE1) and neural cell adhesion molecule 1 (NCAM1). Non-coding RNAs such as microRNA-6789 (miR-6789), miR-5006, and miR-7107 were also upregulated. Pathway analysis suggested that enhanced cell survival, invasion, and apoptosis resistance in 5-FU-resistant cells may be due to the activation of several genes in the PI3K-AKT signaling pathway. In conclusion, our findings describe the transcriptomic features of chemoresistant CRC cells that are associated with aggressive tumor behavior. These insights may support the development of targeted therapies to overcome 5-FU resistance in CRC.