Effect of Chloroquine on Expression of Apoptosis and Autophagy Genes in MOLT-3 and IMR-32 Cells

The study was aimed to compare the effect of chloroquine (CQ)on the expression of apoptosis and autophagy genes in the two tumorcell lines, leukemia MOLT-3 and neuroblastoma IMR-32, cultured in parallelin complete growth and serum-free RPMI-1640 or DMEM media, respectively,for 24 and 48 h. Cell viability was assessed by the MTT method,gene expression—by real-time PCR. For MTT assay, the cells wereincubated with 10–100 µM CQ. The expression of apoptosis (CASP3, BAX, BCL2) and autophagy (ULK1, BECN1, MAP1LC3B) genes was studied using30 and 50 µM CQ, which exerted a considerable inhibitory effecton the viability of cell of both lines, but did not cause theircomplete death. The sensitivity of both cell lines to CQ was higherin the serum-free medium, however, the expression of apoptosis andautophagy genes substantially differed between them. In MOLT-3 cells,mRNA levels of the pro-apoptotic genes CASP3 and BAX increased after 24-h incubationin the serum-free medium, whereas in IMR-32 cells, the expressionof these genes increased only after 48-h incubation in the presenceof higher CQ concentration. In the cells of both lines, 24-h CQtreatment resulted in enhanced expression of the anti-apoptoticgene BCL2. Under conditionsof nutrient deficiency, the genes responsible for the three stagesof autophagy (ULK1, BECN1, MAP1LC3B)demonstrated different combinations of their stimulation in MOLT-3cells, but none of the treatment protocols influenced ULK1 and MAP1LC3B geneexpression in IMR-32 cells. Overall, a 24-h treatment with CQ under conditionsof serum starvation is optimal for autophagy modulation in MOLT-3cells. In IMR-32 cells, CQ exerts no considerable effect on theexpression of autophagy genes, and their decreased viability appearsto be due to activation of other mechanisms.