[Synergistic Effect of Combination of Flumatinib with Chidamide in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia].

Objective: To explore the synergistic effect of flumatinib (FLU) combined with histone deacetylase inhibitor chidamide (CHI) and underlying mechanism on Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ ALL) SUP-B15 cells.

Methods: CCK-8 method was used to examine the effects of FLU, CHI alone and combination therapy on the proliferation of SUP-B15 cells. Flow cytometry was utilized to analyze the cell cycle and apoptosis. RT-qPCR and Western blot methods were performed to detect target gene expression.

Results: FLU combined with CHI significantly inhibited the proliferation, induced G₀/G₁ phase arrest, and increased the apoptosis rate in SUP-B15 cells compared with FLU and CHI alone. The 50 genes were identified by overlapping the two drugs' targets of action with Ph⁺ ALL oncogenic genes in the public databases, and p53 and c-Myc transcription factors and PI3K/AKT signaling pathways were enriched in the overlapped genes. The combination of FLU and CHI significantly reduced the mRNA level of BCR::ABL fusion gene, up-regulated the protein and mRNA levels of p53, BAX, and Caspase-3, and down-regulated the protein and mRNA levels of c-Myc, PIK3CA, PIK3CB, and AKT2 compared with single-drug therapy. The analysis of GEO database and our center cohort showed that c-Myc, PIK3CA, PIK3CB, and AKT2 were significantly up-regulated while p53 was down-regulated in Ph⁺ ALL patients compared to healthy controls.

Conclusion: FLU combined with CHI synergistically inhibits cell proliferation, promotes apoptosis, and induces cycle arrest by targeting the PI3K/AKT signaling pathway through the p53/c-Myc axis in Ph⁺ ALL.