Study On the Expression of 14-3-3ζ in Acute Myeloid Leukemic Cell Lines

It is known that one of main reasons of refractory and relapsed acute myeloid leukemia (AML) is multidrug resistant (MDR). Despite it was showed that 14-3-3ζ was over- expressed in HL-60/VCR MDR cells than in HL-60 sensitive AML cells by examining the difference of gene expression profile with Affymetrix GeneChip Human Genome U133 set A. Yet, the understanding on role of 14-3-3ζ in the survival of AML cells remains poor.

Semi-quantitative RT-PCR method was used to examine the expression of mdr1 mRNA in AML cell lines to validate the results of microarray. Western blot was performed to investigate Pgp#x2610;A14-3-3ζ#x2610;ABCL-2#x2610;AMCL-1 proteins expression. Immunofluorescence assay was used to detect the subcellular location of 14-3-3ζ protein in HL-60 and HL-60/VCR cells by laser scanning confocal microscope. 14-3-3ζ knockdown cells were obstained by transduction with lentivirus-mediated shRNA to silence 14-3-3ζ in AML cell lines. MTT and cell count method were used to analyze the changes of growth of AML cells.

mdr1 mRNA and Pgp was not expressed in HL-60 cells, but significantly overexpressed in HL-60/VCR cells(P<0.01). Except 14-3-3σ, the expression of other subtypes of 14-3-3 was higher in HL-60/VCR cells than in HL-60 cells, especially 14-3-3ζ(P<0.01). The higher increased expression of 14-3-3ζ, BCL-2, MCL-1 protein was observed in HL-60/VCR cells than in HL-60 cells. These results were same as gene chip. It was also noticed that14-3-3ζ was located in the cytoplasma and nuclear of AML cell lines, especially over-expressed in HL-60/VCR cells(P<0.05). Furthermore, suppression of14-3-3ζ by RNA interference resulted in inhibition of the proliferation of AML cells with BCL-2 and MCL-1 decreased protein expression, especially in HL-60/VCR cells(P<0.01).

It was implied that14-3-3ζ played an important role in AML MDR and was associated with BCL-2 and MCL-1 expression. These results suggested that development of therapy targeting 14-3-3ζ may provide novel, effective strategies for refractory and relapsed AML.

No relevant conflicts of interest to declare.