Transcriptome analysis of resistant colon adenocarcinoma cells after treatment with symmetric selenoesters

Doxorubicin resistant Colo 320/MDR-LRP (ATCC-CCL-220.1) cell line expressing ABCB1, was purchased from LGC Promochem (Teddington, UK). The cells were cultured in RPMI-1640 medium supplemented with 10% heat-inactivated fetal bovine serum (FBS), 2 mM L-glutamine, 1 mM Na-pyruvate, 100 mM Hepes, nystatin and a penicillin-streptomycin mixture in concentrations of 100 U/L and 10 mg/L, respectively. The density of the cells was adjusted to 5?105 cells in 1 ml of RPMI medium and the cells were transferred in 1 ml aliquots into a 24-well plate. After an overnight incubation the cells were treated with different selenoesters1 using a non-toxic concentration based on their respective IC50. The samples were prepared in triplicates using an untreated control and selenoesters as follows: - methylketone selenoester EDAG-1 and EDAG-5 were applied at 0.25 µM - methyloxycarbonyl selenoester EDAG-6 was applied at 1 µM - cyano-selenoesters EDAG-10 and EDAG-11 were applied at 0.5 µM After the incubation of 24 h in a humidified atmosphere (5% CO2, 95% air) at 37 ºC the cells were removed from the 24-well-plate using a cell scraper. Then, RNA isolation and cDNA library preparation and whole transcriptome sequencing was performed by DeltaBio 2000 Kft. (Szeged, Hungary). The libraries were pooled and mixed with 1% PhiX DNA and sequenced on Illumina NextSeq 550 sequencing platform with NextSeq 500/550 High Output Kit v2.5 in 75 cycles (Illumina).