Figure 2.

Expression levels of miR-21-5p in SGC7901 and SGC7901/DOX cells. (A) Native SGC7901 cells those with acquired resistance to three different concentrations of DOX were incubated with various doses of DOX for 48 h, and the cell viability was determined using a cell counting kit-8 assay. (B) The IC₅₀ values of SGC7901 and three DOX-resistant cell lines were calculated. (C) Reverse transcription quantitative-polymerase chain reaction analysis indicated that miR-21-5p was significantly upregulated in SGC7901/DOX cells compared with those in SGC7901 cells. ^**P<0.01 and ^***P<0.001. DOX, doxorubicin; SGC7901/DOX, DOX-resistant SGC7901 cell line; IC₅₀, concentration causing 50% growth inhibition; miR, microRNA.