Modulatory effects of human bone marrow-derived mesenchymal stem cells on proliferation and ultrastructural changes in K562 leukemic cells

Mesenchymal stem cells (MSCs) have been reported to possess modulatory effects on various types of cancers as well as immunomodulatory properties, which have intrigued many researchers. Over the past two decades, there has been a focus in literature on the interaction between MSCs and leukemias. However, the interactions between the MSCs and leukemic cells, in particular the k562 cells, have not been well documented. The aim of this study was to demonstrate the interactions between human bone marrow-derived MSCs (hBM-MSCs) on a chronic myeloid leukemic cell line (K562 cells). Co-culture of K562 cells with the hBM-MSC increased the viability of these cells in noncontact and contact co-culture conditions. The same was observed when the K562 cells were cultured in hBM-MSC conditioned medium. Transmission electron microscopy (TEM) of K562 cells co-cultured with hBM-MSCs showed significant ultra-structural observations consistent with biochemical assays performed. The findings suggest that although cell-to-cell interaction is required for effective modulatory effect to occur, soluble substance secreted by the hBM-MSCs may also be able to emulate similar effects.