<b>Mechanisms of Modified Qinghao Biejia Decoction in Reversing Drug Resistance in K562/ADM Cells via Autophagy Inhibition</b> (Supplementar data).xlsx

<b>Abstract</b><b>Background:</b> Multidrug resistance (MDR) in leukemia, especially chronic myeloid leukemia (CML), is a major challenge to the effectiveness of chemotherapy regimens. One of the more well-known cytopathies is autophagy, a lysosome-dependent catabolic process associated with oncogenesis and chemoresistance.<b>Objective:</b> This study aims to evaluate the ability of a Modified Qinghao Biejia Decoction (MQBD), a traditional Chinese medicinal (TCM), to reverse ADM resistance in the K562/ADM human leukemia cell line. The hypothesis is that MQBD suppresses autophagy, a cell survival mechanism that promotes drug resistance.<b>Methods:</b> The study employed serum pharmacology, K562/ADM cell culture, a CCK-8 cytotoxicity assay, monodansylcadaverine (MDC) staining of autophagic vacuoles, and Western blotting for LC3 protein. Blood samples were collected from rabbits treated with MQBD at different concentrations. The experimental groups were ADM alone, 3MA, FD, FZ, FG, and FD combined with FZ or FG.<b>Results:</b> The viability of K562/ADM cells was reduced dose-dependent by MQBD, as determined by CCK-8 assays. High-dose MQBD (FG) had a more potent effect on cell viability decrease (24.15% inhibition), and the combination with 3MA increased the inhibition to 48.39%. The mean fluorescence intensity of MDC, which measures the level of autophagic vacuoles, was significantly decreased in the FG and FG+3MA groups, which implies a decrease in autophagic flux. Western blot analysis showed that the expression ratio of LC3-II/LC3-I was reduced in a dose-dependent manner, and the FG+3MA group had the lowest level, indicating the inhibition of MQBD-induced autophagy.<b>Conclusion:</b> MQBD has the opposite effect of MDR by down-regulating autophagy in K562/ADM cells, as demonstrated by the reduced number of autophagosomes and LC3 expression. These findings suggest that MQBD may be a complementary agent in treating MRD in CML.