Increased inducible heat shock protein 72 expression associated with PBMC isolated from patients with haematological tumours

Abstract

Background. Heat shock protein 72 (Hsp72) is a highly inducible stress protein and molecular chaperone. Cancers have been shown to be associated with increased Hsp72 expression within the tumour itself and this may lead to resistance to apoptosis. Methods. Peripheral blood mononuclear cells (PBMC) were isolated from patients diagnosed with chronic lymphocytic leukaemia (CLL) (n = 27) and chronic myelomonocytic leukaemia (CMML) (n = 16) and Hsp72 expression was characterized on both the cell surface and intracellularly by flow cytometry. To allow for comparison PBMC from breast cancer patients (n = 25) and healthy volunteers (n = 19) were included. Results. Both lymphocytes and monocytes from CLL and CMML patients showed high levels of total Hsp72 expression (4–6 fold increase) in comparison to breast cancer and healthy subjects. The majority of Hsp72 in these tumours was determined to be cell-surface expressed (64–93% of cell total Hsp72). Conclusions. A correlation was observed between lymphocyte and monocyte total Hsp72 expression (p < 0.001) suggesting a common stress response pathway may exist in these blood cells and there are stress conditions present within the circulation. Hsp72 expression was not found to be related to white blood cell count.

Key Words::

• Heat shock protein
• hsp72
• leukaemia
• monocyte
• lymphocyte

Acknowledgements

The authors would like to thank Dr Victoria Green, Mariel O’Connor, Heather Yeung, and Ben Sadowyj for their contribution to the study.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.