Objective: To explore correlation of seven apoptosis-related proteins (Hsp90a, p53, MDM2, Bcl-2, Bax, Cytochrome C, and Cleaved caspase3) with clinical outcomes of ALK+ anaplastic large-cell lymphoma (ALCL).
Methods: Using immunohistochemistry and immunofluorescence double staining methods, the expressions of these seven apoptosis-associated proteins were studied to clarify their relationship with clinical outcomes of 36 ALK+ and 25 ALK-systemic ALCL patients enrolled between 1996 and 2006. The relationship of these apoptosis-regulating proteins with NPM-ALK status was also evaluated with the tyrosine inhibitor herbimycin A (HA) in vitro by immunocytochemistry, Western blotting and flow cytometric assays.
Results: The presence of Hsp90α-, MDM2-, Bax-, Cytochrome C, and Cleaved caspase3-positive tumor cells was found significantly different in ALK+ and ALK-ALCLs, which was correlated with highly favorable clinical outcome. The Bcl-2- and p53-positive tumor cells were found in groups of patients with unfavorable prognosis. Inhibition of NPM-ALK by HA could reactivate the p53 protein and subsequent apoptosis-related proteins and therefore induced apoptosis in ALK+ ALCL cells.
Conclusion: Our results suggest that these seven proteins might be involved in apoptosis regulation and associated with clinical outcome of ALK+ systemic ALCLs. We also reveal a dynamic chain relation that NPM-ALK regulates p53 expression and subsequent apoptosis cascade in ALK+ ALCLs.
Copyright © 2011 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.