SYK-dependent tonic B-cell receptor signaling is a rational treatment target in diffuse large B-cell lymphoma.
The role of B-cell receptor (BCR)-mediated survival signals in diffuse large B-cell lymphoma (DLBCL) remains undefined. Ligand-induced BCR signaling induces receptor oligomerization, Igalpha/beta immunoreceptor tyrosine-based activation motif (ITAM) phosphorylation, and activation of the spleen tyrosine kinase (SYK), which initiates downstream events and amplifies the initial BCR signal. BCRs also transmit low-level tonic survival signals in the absence of receptor engagement. Herein, we assess the role of SYK-dependent tonic BCR survival signals in DLBCL cell lines and primary tumors and evaluate the efficacy of an ATP-competitive inhibitor of SYK, R406, in vitro. R406 induced apoptosis of the majority of examined DLBCL cell lines. In R406-sensitive DLBCL cell lines, R406 specifically inhibited both tonic- and ligand-induced BCR signaling (autophosphorylation of SYK525/526 and SYK-dependent phosphorylation of the B-cell linker protein [BLNK]). The majority of examined primary DLBCLs also exhibited tonic- and ligand-induced BCR signaling; in these primary tumors, BCR signaling was also inhibited by R406. Of note, BCR-dependent and R406-sensitive DLBCL cell lines were independently identified as "BCR-type" tumors by transcriptional profiling. Therefore, SYK-dependent tonic BCR signaling is an important and potentially targetable survival pathway in some, but not all, DLBCLs. In addition, R406-sensitive DLBCLs can be identified by their transcriptional profiles.
Chen
Linfeng
L
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
Monti
Stefano
S
Juszczynski
Przemyslaw
P
Daley
John
J
Chen
Wen
W
Witzig
Thomas E
TE
Habermann
Thomas M
TM
Kutok
Jeffery L
JL
Shipp
Margaret A
MA
D017209:Apoptosis / Q000187:drug effects; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000633:toxicity; D005434:Flow Cytometry; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D010078:Oxazines / Q000633:toxicity; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D011725:Pyridines / Q000633:toxicity; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D000072377:Syk Kinase; D014158:Transcription, Genetic
D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; C510788:N4-(2,2-dimethyl-3-oxo-4H-pyrid(1,4)oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine; D010078:Oxazines; D011725:Pyridines; D011947:Receptors, Antigen, B-Cell; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase