TY - JOUR
T1 - Follicular lymphoma-associated btk mutations are inactivating resulting in augmented akt activation
AU - Hu, Nan
AU - Wang, Fangyang
AU - Sun, Tianyu
AU - Xu, Zhengfan
AU - Zhang, Jing
AU - Bernard, Denzil
AU - Xu, Shilin
AU - Wang, Shaomeng
AU - Kaminski, Mark
AU - Devata, Suma
AU - Phillips, Tycel
AU - Malek, Sami N.
N1 - Funding Information:
We are grateful for services provided by the genomics, bioinformatics, and flow cytometry cores of the University of Michigan Rogel Comprehensive Cancer Center. We are also grateful to the contribution of the hematological malignancy group of the University of Michigan through NCI CCSG – grant number P30CA046592.
Funding Information:
S. Malek reports grants and personal fees from Janssen and Pharmacyclics during the conduct of the study; other from Abbvie outside the submitted work. S. Wang reports grants from NCI, NIH during the conduct of the study; grants and personal fees from Oncopia Therapeutics Inc outside the submitted work; and is a co-founder and a paid consultant for Oncopia Therapeutics Inc and owns shares in Oncopia Therapeutics Inc, which has licensed a number of protein degrader patents from the University of Michigan, however, no patent has been filed on the BTK degraders used in this work. No disclosures were reported by the other authors.
Funding Information:
This work was supported in part by R01CA190384, Janssen R&D and Pharmacyclics 16-PAF02251, a University of Michigan Rogel Cancer Center Scholar award (all to S.N. Malek) and the Weatherhall foundation (to M. Kaminski). We are grateful for services provided by the genomics, bioinformatics, and flow cytometry cores of the University of Michigan Rogel Comprehensive Cancer Center. We are also grateful to the contribution of the hematological malignancy group of the University of Michigan through NCI CCSG - grant number P30CA046592.
Funding Information:
This work was supported in part by R01CA190384, Janssen R&D and Pharma-cyclics 16-PAF02251, a University of Michigan Rogel Cancer Center Scholar award (all to S.N. Malek) and the Weatherhall foundation (to M. Kaminski).
Publisher Copyright:
© 2021 American Association for Cancer Research.
PY - 2021/4
Y1 - 2021/4
N2 - Purpose: On the basis of the recent discovery of mutations in Bruton tyrosine kinase (BTK) in follicular lymphoma, we studied their functional properties. Experimental Design: We identified novel somatic BTK mutations in 7% of a combined total of 139 follicular lymphoma and 11 transformed follicular lymphoma cases, none of which had received prior treatment with B-cell receptor (BCR) targeted drugs. We reconstituted wild-type (WT) and mutant BTK into various engineered lymphoma cell lines. We measured BCR-induced signal transduction events in engineered cell lines and primary human follicular lymphoma B cells. Results: We uncovered that all BTK mutants destabilized the BTK protein and some created BTK kinase-dead mutants. The phospholipase C gamma 2 (PLCg2) is a substrate of BTK but the BTK mutants did not alter PLCg2 phosphorylation. Instead, we discovered that BTK mutants induced an exaggerated AKT phosphorylation phenotype in anti-Ig-treated recombinant lymphoma cell lines. The short hairpin RNA-mediated knockdown of BTK expression in primary human nonmalignant lymph node-derived B cells resulted in strong anti-Ig-induced AKT activation, as did the degradation of BTK protein in cell lines using ibrutinib-based proteolysis targeting chimera. Finally, through analyses of primary human follicular lymphoma B cells carrying WT or mutant BTK, we detected elevated AKT phosphorylation following surface Ig crosslinking in all follicular lymphoma B cells, including all BTK-mutant follicular lymphoma. The augmented AKT phosphorylation following BCR crosslinking could be abrogated by pretreatment with a PI3Kd inhibitor. Conclusions: Altogether, our data uncover novel unexpected properties of follicular lymphoma-associated BTK mutations with direct implications for targeted therapy development in follicular lymphoma. See related commentary by Afaghani and Taylor, p. 2123.
AB - Purpose: On the basis of the recent discovery of mutations in Bruton tyrosine kinase (BTK) in follicular lymphoma, we studied their functional properties. Experimental Design: We identified novel somatic BTK mutations in 7% of a combined total of 139 follicular lymphoma and 11 transformed follicular lymphoma cases, none of which had received prior treatment with B-cell receptor (BCR) targeted drugs. We reconstituted wild-type (WT) and mutant BTK into various engineered lymphoma cell lines. We measured BCR-induced signal transduction events in engineered cell lines and primary human follicular lymphoma B cells. Results: We uncovered that all BTK mutants destabilized the BTK protein and some created BTK kinase-dead mutants. The phospholipase C gamma 2 (PLCg2) is a substrate of BTK but the BTK mutants did not alter PLCg2 phosphorylation. Instead, we discovered that BTK mutants induced an exaggerated AKT phosphorylation phenotype in anti-Ig-treated recombinant lymphoma cell lines. The short hairpin RNA-mediated knockdown of BTK expression in primary human nonmalignant lymph node-derived B cells resulted in strong anti-Ig-induced AKT activation, as did the degradation of BTK protein in cell lines using ibrutinib-based proteolysis targeting chimera. Finally, through analyses of primary human follicular lymphoma B cells carrying WT or mutant BTK, we detected elevated AKT phosphorylation following surface Ig crosslinking in all follicular lymphoma B cells, including all BTK-mutant follicular lymphoma. The augmented AKT phosphorylation following BCR crosslinking could be abrogated by pretreatment with a PI3Kd inhibitor. Conclusions: Altogether, our data uncover novel unexpected properties of follicular lymphoma-associated BTK mutations with direct implications for targeted therapy development in follicular lymphoma. See related commentary by Afaghani and Taylor, p. 2123.
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U2 - 10.1158/1078-0432.CCR-20-3741
DO - 10.1158/1078-0432.CCR-20-3741
M3 - Article
C2 - 33419778
AN - SCOPUS:85104295415
SN - 1078-0432
VL - 27
SP - 2301
EP - 2313
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 8
ER -