Decitabine has a biphasic effect on natural killer cell viability, phenotype, and function under proliferative...

Area of Science:

• Immunology
• Cancer Biology
• Epigenetics

Background:

• DNA hypermethylation is crucial in acute myelogenous leukemia (AML) oncogenesis.
• NK cell receptor modulation is a key immune escape mechanism in AML.
• Decitabine (DAC) is a cytidine analog with hypomethylating and cytotoxic properties.

Purpose of the Study:

• To investigate the direct effects of decitabine on NK cell phenotype, proliferation, survival, and function.
• To distinguish decitabine's direct toxicity from its hypomethylating effects on NK cells.
• To determine optimal decitabine concentrations for immunomodulation in AML treatment.

Main Methods:

• Human peripheral blood NK cells were cultured with decitabine at concentrations ranging from 0.02 to 5μM.
• Cells were assessed for viability, proliferation, cytotoxicity, receptor expression, and global DNA methylation.
• Static and proliferation-inducing culture conditions were used to differentiate effects.

Main Results:

• Low decitabine concentrations increased killer immunoglobulin-like receptor (KIR) and NKp44 expression.
• High decitabine concentrations decreased NK cell viability, proliferation, and NKG2D expression.
• Decitabine exhibited a biphasic effect on NK cell lytic function and global DNA hypomethylation.

Conclusions:

• Decitabine affects NK cell receptor expression at low doses during proliferation.
• High decitabine doses inhibit NK cell proliferation and viability via direct toxicity.
• Optimal immunomodulation with decitabine occurs at low doses, with high doses being detrimental to NK cell function.