Cytokine-Primed Mesenchymal Stromal Cells Enhance Antitumor Immunity-Associated Gene Expression without Promoting Acute Myeloid Leukemia Cell Growth.

Purpose: Mesenchymal stromal cells (MSCs), while regarded as promising immunomodulatory tools, have raised concerns in recent studies for their potential to promote tumor growth or facilitate immune evasion. These risks are particularly relevant in hematologic malignancies, where MSCs have been used to mitigate graft-versus-host disease or support hematopoietic engraftment. This study aimed to evaluate the effects of cytokine-primed MSCs on acute myeloid leukemia (AML) cells, with a focus on both safety and immunomodulatory efficacy. Materials and Methods: Wharton's jelly-derived MSCs were primed with interferon-γ (IFN-γ), interleukin-6, lipopolysaccharide, and tumor necrosis factor-α, followed by co-culture with AML cell lines. AML cell viability was measured by Cell Counting Kit-8 assay. RNA sequencing and quantitative real-time polymerase chain reaction were performed to assess gene expression profiles under each priming condition. Results: Cytokine-primed MSCs did not result in significant changes in AML cell viability (p > 0.05), supporting the safety of this approach. Meanwhile, IFN-γ priming significantly upregulated genes involved in immune modulation and apoptosis, including IDO1, TNFSF10, ICAM1, and chemokines CXCL9, CXCL10, and CXCL11. Conclusion: Cytokine priming, particularly with IFN-γ, enhanced the immunomodulatory gene expression of MSCs without promoting AML cell proliferation. Although direct cytotoxic effects were not observed in co-culture experiments, the absence of increased leukemic cell growth under any priming condition supports the biological safety of this approach. These findings provide a strong foundation for further in vivo studies to assess the therapeutic applicability of primed MSCs in hematologic malignancies while ensuring oncologic safety.