Choosing the right cell line for rectal cancer research

Abstract

Up to date no effective method exists that predicts response to preoperative chemoradiation (CRT) in locally advanced rectal cancer (LARC). Nevertheless, identification of patients who have a higher likelihood of responding to preoperative CRT could be crucial in decreasing treatment morbidity and avoiding expensive and time-consuming treatments. Using the Gng4, c-Myc, Pola1, and Rrm1 signature, we were able to establish a model to predict response to CRT in rectal cancer with a sensitivity of 60% and 100% specificity. The aim of this study was to characterize c-Myc status in DNA, RNA and protein levels in 3 tumoral cell lines (SW480, SW620 and SW837) to establish the best cell line model and, subsequently, carry out genome silencing of c-Myc by means of RNA interference (iRNA). To study the expression levels of c-Myc, we used Polymerase Chain Reaction (PCR) amplifications and sequencing; quantitative real time PCR (qRT-PCR); and western blot analysis in each cell line. SW480 and SW620 showed a variation A > G in exon 2, which caused a substitution of aspargine to serine, and SW837 revealed a G > A transition in the same, which caused a mutation at codon 92. The three cell lines expressed c-Myc mRNA. SW837 showed a decrease of c-Myc expression levels compared with SW480, and SW620. At protein level, SW620 showed the highest expression of c-Myc. According to the results obtained, we can perform c-Myc gene silencing experiments to analyze the role of this biomarker in response to treatment.