[The Synergistic Anti-Leukemia Effect of Bcl-2 Inhibitor Combined with HDAC Inhibitor by PI3K/AKT/FoxO1 Axis in...

To investigate the mechanism of the synergistic anti-leukemia effect of the combination of Bcl-2 inhibitor venetoclax (VEN) and histone deacetylase (HDAC) inhibitor chidamide (CDM) in T-cell acute lymphoblastic leukemia (T-ALL).

The effect of VEN combined with CDM on the proliferation of T-ALL CEM and MOLT-4 cell lines was detected by CCK-8 assay. And the effects on the cell cycle and apoptosis were detected by flow cytometry. Cell cycle protein and apoptosis-related protein expression were detected by Western blot. The key pathways of VEN combined with CDM in T-ALL were screened through network pharmacology analysis, and verifying them in T-ALL cell lines, T-ALL patient cells and public databases.

VEN combined with CDM displayed a synergistic effect on cell proliferation of CEM and MOLT-4 cells. In cell cycle experiment, VEN combined with CDM induced G₀/G₁ phase arrest in CEM and MOLT-4 cells. Western blot experiment showed that VEN combined with CDM could significantly downregulate the expression of cyclin E2 and CDK2 and upregulate the expression of p21^Waf1/Cip1. In the apoptosis experiment, VEN combined with CDM could significantly induce the apoptosis of CEM and MOLT-4 cells. Western blot experiment demonstrated that VEN combined with CDM promoted endogenous apoptosis by downregulating Mcl-1 and upregulating Bax and cleaved caspase-3 protein levels. Network pharmacology analysis identified 10 hub genes. KEGG enrichment analysis revealed the cell cycle, PI3K-AKT signaling pathway, and its downstream FoxO signaling pathway were significantly enriched. GO enrichment analysis revealed the G₁/S transition of mitotic cell cycle, cyclin-dependent protein kinase holoenzyme complex, and kinase activity were significantly enriched. Western blot experiment showed that VEN combined with CDM could significantly downregulate the protein level of PI3K, AKT, and p-AKT, and upregulate FoxO1 in CEM and MOLT-4 cells. In T-ALL patients, FoxO1 showed significantly lower expression compared to the normal donors, and the same result was verified in the GSE13159 and GSE26713 datasets.

The combination of VEN and CDM exerts synergistic anti-leukemia effects by inhibiting cellular proliferation, inducing G₀/G₁ phase arrest and promoting apoptosis through PI3K/AKT/FoxO1 axis in T-ALL.