Moya Ramírez, Miguel Ángel¹,2 *; Sánchez Martín, Victoria¹,2 *; Herrera Merchán, Antonio¹,³; Medina Vico, Pedro ¹ ,³ and Cuadros Celorrio, Marta ¹ , 2
(1) Department of Biochemistry and Molecular Biology III and Immunology, University of Granada, Granada, Spain.
(2) GENYO, Centre for Genomics and Oncological Research: Pfizer/University of de Granada/Junta de Andalucía, Granada, Spain.
(3) Department of Biochemistry and Molecular Biology I, University of Granada, Granada, Spain.
(*) These two authors contributed equally to this work.
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 (SW 480, SW 620 and SW 837) 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. SW 480 and SW 620 showed a variation A > G in exon 2, which caused a substitution of aspargine to serine, and SW 837 revealed a G > A transition in the same, which caused a mutation at codon 92. The three cell lines expressed c-Myc mRNA . SW 837 showed a decrease of c-Myc expression levels compared with SW 480, and SW 620. At protein level, SW 620 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.
c-Myc, rectal tumor, response, cell lines.