Essential role of the linear ubiquitin chain assembly complex in lymphoma revealed by rare germline polymorphisms.
Constitutive activation of NF-κB is a hallmark of the activated B cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL), owing to upstream signals from the B-cell receptor (BCR) and MYD88 pathways. The linear polyubiquitin chain assembly complex (LUBAC) attaches linear polyubiquitin chains to IκB kinase-γ, a necessary event in some pathways that engage NF-κB. Two germline polymorphisms affecting the LUBAC subunit RNF31 are rare among healthy individuals (∼1%) but enriched in ABC DLBCL (7.8%). These polymorphisms alter RNF31 α-helices that mediate binding to the LUBAC subunit RBCK1, thereby increasing RNF31-RBCK1 association, LUBAC enzymatic activity, and NF-κB engagement. In the BCR pathway, LUBAC associates with the CARD11-MALT1-BCL10 adapter complex and is required for ABC DLBCL viability. A stapled RNF31 α-helical peptide based on the ABC DLBCL-associated Q622L polymorphism inhibited RNF31-RBCK1 binding, decreased NF-κB activation, and killed ABC DLBCL cells, credentialing this protein-protein interface as a therapeutic target.


CONCLUSIONS
We provide genetic, biochemical, and functional evidence that the LUBAC ubiquitin ligase is a therapeutic target in ABC DLBCL, the DLBCL subtype that is most refractory to current therapy. More generally, our findings highlight the role of rare germline-encoded protein variants in cancer pathogenesis.
1Lymphoid Malignancies Branch, 2Laboratory of Pathology, 3Experimental Immunology Branch, Center for Cancer Research; 4Biometric Research Branch, DCTD, National Cancer Institute; 5Hematology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland; 6Department of Pathology, University of Arizona, Tucson, Arizona; 7Oregon Health and Science University, Portland, Oregon; 8Cleveland Clinic Pathology and Laboratory Medicine Institute, Cleveland, Ohio; 9Department of Pathology, City of Hope National Medical Center, Duarte, California; 10Departments of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska; 11Department of Pathology, University of Würzburg, Würzburg; 12Department of Clinical Pathology, Robert-Bosch-Krankenhaus; 13Dr. Margarete Fischer-Bosch Institute for Clinical Pharmacology, Stuttgart, Germany; 14British Columbia Cancer Agency, Vancouver, British Columbia, Canada; 15Hospital Clinic, University of Barcelona, Barcelona, Spain; 16Pathology Clinic, 17Institute for Cancer Research, Rikshospitalet University Hospital; 18Center for Cancer Biomedicine, Faculty Division of the Norwegian Radium Hospital, University of Oslo, Oslo, Norway; and 19Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Yibin
Y
Yang
Roland
R
Schmitz
Joseph
J
Mitala
Amanda
A
Whiting
Wenming
W
Xiao
Michele
M
Ceribelli
George W
GW
Wright
Hong
H
Zhao
Yandan
Y
Yang
Weihong
W
Xu
Andreas
A
Rosenwald
German
G
Ott
Randy D
RD
Gascoyne
Joseph M
JM
Connors
Lisa M
LM
Rimsza
Elias
E
Campo
Elaine S
ES
Jaffe
Jan
J
Delabie
Erlend B
EB
Smeland
Rita M
RM
Braziel
Raymond R
RR
Tubbs
James R
JR
Cook
Dennis D
DD
Weisenburger
Wing C
WC
Chan
Adrian
A
Wiestner
Michael J
MJ
Kruhlak
Kazuhiro
K
Iwai
Federico
F
Bernal
Louis M
LM
Staudt
D001665:Binding Sites; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D014644:Genetic Variation; D018095:Germ-Line Mutation; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics* / Q000473:pathology; D008958:Models, Molecular; D010455:Peptides / Q000138:chemical synthesis / Q000494:pharmacology; D020641:Polymorphism, Single Nucleotide; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017433:Protein Structure, Secondary; D014157:Transcription Factors / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism*; D000097782:NF-kappaB-Inducing Kinase
D010455:Peptides; D017346:Protein Serine-Threonine Kinases; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D000097782:NF-kappaB-Inducing Kinase; C504507:RBCK1 protein, human; C558338:RNF31 protein, human