Expression of heat shock protein 70 and NKG2D ligands in acute myeloid leukemia cell lines

Abstract

Membrane-bound heat shock protein 70 (HSP70) was found to be tumor-specific and was proposed as a target for immunotherapy. In the present study, we analyzed cell surface and relative gene expression of HSP70 in cell lines established from patients with different acute myeloid leukemia (AML) subtypes, together with the expression of natural killer (NK) cell activation/inhibitory ligands.

Materials and methods: Six AML cell lines were included in this study. The relative gene expression of HSP70 was analyzed using the real-time reverse-transcriptase polymerase chain reaction. Surface expression of HSP70 and NK cell ligands was analyzed using flow cytometry.

Results: All cell lines overexpressed HSP70; however, its mRNA levels were not elevated. The expression of NKG2D activation ligands was heterogeneous.

Conclusion: Our study is the first to describe long-term stationary cell surface expression of HSP70 in different subtypes of AML. Combined with the results of the gene expression experiments these data provide more evidence to the idea of a self-limiting mechanism for HSP70 expression.

Keywords::

• HSP70
• acute myeloid leukemia
• gene expression
• cell surface expression
• NK cell ligands
• RT-PCR

Acknowledgements

The authors would like to thank Dr Michelle Le Beau from the University of Chicago Cancer Research Centre (USA), Prof. Dr Jerzy Adamski from Helmholtz Zentrum München (Germany) and Professor Doris A. Morgan, Drexel University College of Medicine, Philadelphia (USA) for the kind gifts of cell lines and Prof. Gabriele Multhoff (Multimmune GmBH, Munich, Germany) for consultations. Our special thanks goes to Olga Koprivova, student of Faculty of Natural Sciences, Charles University Prague, for the participation in the collection of experimental data.

Declaration of interests

This project was funded by TRANSNET (No. MRTN-CT-2004-512253) and STEMDIAGNOSTICS (No. LSHB-CT-2007-037703). The authors report no declarations of interest.