HSP90 promotes Burkitt lymphoma cell survival by maintaining tonic B cell receptor signaling

ABSTRACT: Burkitt’s lymphoma (BL) is an aggressive B-cell neoplasm that is currently treated by intensive chemotherapy in combination with anti-CD20 antibodies. Because of their toxicity, current treatment regimens are often not suitable for elderly patients or for patients in developing countries where BL is endemic. Hence, there is a need for targeted therapies. In this study, we performed a compound screen in 17 BL cell lines to identify small molecule inhibitors affecting cell survival. We observed that, among other compounds, inhibitors of heat shock protein 90 (HSP90) induce apoptosis in BL cells in vitro at concentrations that did not affect normal B cells. By global proteomic and phosphoproteomic profiling, we found that in BL, HSP90 inhibition compromises activity of the pivotal B cell antigen receptor (BCR)-proximal effector spleen tyrosine kinase (SYK), which we identified as an HSP90 client protein. Consistently, expression of constitutively active TEL-SYK counteracted the apoptotic effect of HSP90 inhibition. Hence, our study provides a molecular rationale for the use of HSP90 inhibitors in the treatment of BL by demonstrating that HSP90 inhibition interferes with tonic BCR signaling and thus impairs BL cell survival.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): B Cell, Cell Culture

DISEASE(S): Lymphoma

SUBMITTER: Kuan-Ting Pan  

LAB HEAD: Henning Urlaub

PROVIDER: PXD004181 | Pride | 2017-01-02

REPOSITORIES: Pride