PLZF regulates apoptosis of leukemia cells by regulating AKT/Foxo3a pathway

To explore the regulatory role of PLZF in the malignant phenotype of non-APL acute myeloid leukemia (AML) and its underlying mechanism.

The expression level of PLZF in AML cell lines KG-1a, HL-60, OCI-AML3, THP-1 and K562 was detected by quantitative Polymerase Chain Reaction (qPCR) and Western blot, respectively. Subsequently, THP-1 cells were divided into mock group (no treatment), scramble group (transfection with scramble shRNA) and shPLZF group (transfection with shPLZF). THP-1 cell line stably expressing shPLZF was constructed, followed by determination of its transfection efficiency by qPCR and Western blot, respectively. The proliferation and colony formation of THP-1 cells were accessed using CCK-8 (cell counting kit-8) assay and colony formation assay, respectively. The apoptotic rate in THP-1 cells was determined using flow cytometry. Protein levels of apoptosis-related genes in THP-1 cells were detected by Western blot. Finally, protein levels of AKT, Foxo3a, pAKT and pFoxo3a were detected by Western blot as well.

Both mRNA and protein levels of PLZF were relatively high in THP-1 cells, and were selected for the following experiments. After construction of THP-1 cell line stably expressing shPLZF, proliferative rate and colony formation abilities increased in the shPLZF group compared with the mock group and the scramble group. We found a decreased apoptotic rate, downregulated Bax and upregulated Bcl-2 in the shPLZF group than those of the mock group and scramble group. Phosphorylation levels of AKT and Foxo3a increased after interference with PLZF, whereas no significant changes in total levels of AKT and Foxo3a were observed.

PLZF inhibits the malignant phenotype of AML by regulating the AKT/Foxo3a pathway.