RT Journal Article SR Electronic T1 Combined Therapy of ATRA and Imatinib Mesylate Decreases BCR-ABL and ABCB1/MDR1 Expression Through Cellular Differentiation in a Chronic Myeloid Leukemia Model JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 2661 OP 2667 DO 10.21873/invivo.12549 VO 35 IS 5 A1 CAMILA ALBUQUERQUE PINTO A1 ADRHYANN JULLYANNE DE SOUSA PORTILHO A1 MARITZA CAVALCANTE BARBOSA A1 MARIA ELISABETE AMARAL DE MORAES A1 JOSÉ ALEXANDRE RODRIGUES DE LEMOS A1 ROMMEL MΑRIO RODRIGUEZ BURBANO A1 CAROLINE AQUINO MOREIRA-NUNES YR 2021 UL http://iv.iiarjournals.org/content/35/5/2661.abstract AB Background/Aim: Chronic Myeloid Leukemia (CML) is a clonal myeloproliferative disease, and a major challenge for the eradication of CML is to understand the cause of the permanence of minimal residual disease (DRM). This work aimed to induce the maturation of leukemic stem cells with All-trans-retinoic acid (ATRA), making them sensitive to treatment with Imatinib (IM). Materials and Methods: K562 cells were treated with IM and with the combined therapy of ATRA together with IM for 48 and 72 h. The expression of BCR-ABL gene and multidrug resistance gene ABCB1 were evaluated using RT-qPCR. Results: The combined ATRA and IM therapy showed a discreet cell differentiation pattern, evidenced by the panoptic morphology analysis at 48 and 72 h of treatment. The BCR-ABL expression showed no statistical difference when treated alone with IM, however in combination with ATRA, the expression was statistically significant in 48 and 72 h (p≤0.0001) and when the treatment groups were compared to each other (p≤0.001). The ABCB1 gene expression showed a decrease in isolated IM therapy (p≤0.05) and in the combination in 48 and 72 h (p≤0.0001). Conclusion: Combined ATRA and IM therapy was shown to be effective in decreasing BCR-ABL and ABCB1 genes, possibly through the differentiation of blast cells, demonstrating that the therapy could be potentially effective in the blast crisis of the disease and for those patients who develop resistance to available CML treatments.