A Novel Non-Genetic Photostable Approach to Labelling Acute Myeloid Leukemia and Bone Marrow Cells with Quantum Dots

Abstract 4818

Acute myeloid leukemia (AML) is a detrimental disease with difficult diagnosis and treatment. Understanding the biology of AML at the molecular and cellular levels would be essential to successful management of the disease. However, the notoriously known difficulty in manipulation of leukemia cells has long hindered the dissection of AML pathogenesis. The advent of CdSe/ZnS quantum dots (QDs) represents an important advancement in the research field of nanotechnology, which have recently also been applied for imaging of live cells. Here, we have introduced a non-genetic approach of marking blood cells, by taking advantage of QD technology. We compared QDs complexed with different vehicles, including a peptide Tat (QDs-Tat), cationic polymer Turbofect (QDs-Tf) and liposome Lipofectamine 2000 (QDs-Lip), in their abilities to mark cells. QDs-Tat showed the highest efficiency in delivery into hematopoietic cells, among the three vehicles. We then examined QDs-Tat labelling of leukemia cell lines, and found that QDs-Tat could label 293T, bone marrow (BM) cells, THP-1, MEG-01 and HL-60 with a decreasing efficiency. The efficiency of QDs-Tat delivery was dependent on the concentration of QDs-Tat applied, but not the length of incubation time. In addition, more uniform intracellular distributions of QDs in 293T and leukemia cells were obtained with QDs-Tat, compared with the granule-like formation obtained with QDs-Lip. Clearly, QD fluorescence was sharp and tolerant to repetitive photo excitations, and could be detected in 293T for up to one week following labelling. In summary, our results suggest that QDs have provided a photostable, non-genetic and transient approach that labels normal and malignant hematopoietic cells in a cell type-, vehicle-, and QD concentration-dependent manner. We expect for potentially wide applications of QDs as an easy and fast tool assisting investigations of various types of blood cells in the near future.