Targeting Calprotectin S100A8/A9 to Overcome AML Progression in DNMT3A-Mutant Cells

To investigate the effects of calprotectin (S100A8/A9) on the biological activity of acute myeloid leukemia (AML) cells harboring a DNA methyltransferase 3A (DNMT3A) mutation and to explore the underlying molecular mechanisms involved.

AML monoclonal cell lines harboring the DNMT3A^R882H mutation were generated via lentiviral transduction and limiting dilution. RNA sequencing was used for differential gene expression analysis, followed by bioinformatic pathway enrichment and gene correlation analyses. The biological effects of paquinimod, a selective S100A8/A9 inhibitor, on DNMT3A^R882H AML cells were assessed via Cell Counting Kit (CCK-8) proliferation assays, Annexin V/PI staining, cell cycle analysis, cell adhesion assays, and transwell migration assays.

Differential gene expression analysis revealed 442 upregulated and 535 downregulated genes in DNMT3A-mutated (DNMT3A^mut) cells compared with those in DNMT3A wild-type (DNMT3A^wt) cells, with the S100A8/A9 complex recurrently enriched in Reactome pathway analysis. Compared with healthy controls, patients with AML presented increased expression of S100A8 and S100A9 and increased expression of DNMT3A^mut cells relative to DNMT3A^wt cells, which was correlated with poor prognosis in patients with AML. There were no notable differences in proliferation among the DNMT3A^mut, DNMT3A^wt, and empty vector cells under normal or starvation conditions. However, paquinimod treatment notably inhibited the proliferation, migration, and adhesion of DNMT3A^mut AML cells in a dose-dependent manner, causing G0/G1 cell cycle arrest, whereas no significant effects on apoptosis were observed. Paquinimod also downregulated key adhesion molecules, including intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), monocyte chemoattractant protein-1 (MCP-1), and matrix metalloproteinase-2 (MMP-2). Additionally, S100A8 and S100A9 expression was upregulated in a dose-dependent manner in response to cytarabine treatment.

Elevated S100A8/A9 expression contributes to the abnormal proliferation, migration, adhesion, and chemoresistance of DNMT3A^mut AML cells. Targeting S100A8/A9 alone or in combination with other treatments represents a promising therapeutic strategy for DNMT3A^mut AML.