Intercellular Interaction Between a Dental Pulp Stem Cell and Leukemia Cells – Support of Acute Myeloid Leukemia

The oral cavity is a site of hematopoietic activity, and metastatic hematological and solid tumors. This study focused on acute myeloid leukemia (AML) due to extensive documentation of its presentation in the gingiva. Despite these reports, it is unclear how AML and other leukemia cells survive in the oral tissue. We investigated intercellular communication between leukemia cells and dental pulp stem cells (DPSCs). DPSCs enhanced the proliferation and adhesion of AML cells (HL-60) and to a lesser extent, myelomoncytic leukemia cells (U937). The erythroleukemia K562 cells showed a delayed trend to proliferate. The communication between DPSCs and HL-60 cells was partly due to gap junctional intercellular communication (GJIC), as indicated by dye transfer. We also noted evidence of tunnelling nanotubules (TNT). Dye transfer was noted in non-adherent cells, suggesting other method of transfer, perhaps by extracellular vesicles. Using SORE-6 that can stratify the HL-60 subset, dye transfer occurred mostly in the subset lowest in the hierarchy. These latter findings were novel since they might provide insights into the behavior of non-leukemia stem cells and their interaction with cells in the oral cavity. In summary, this study began to dissect the interaction between HL-60 AML cells and DPSCs, providing insights into the survival of AML and perhaps other leukemia cells in the oral cavity.