title: Inhibition of Lyn is a promising treatment for mantle cell lymphoma with bortezomib resistance.
abstract: Although proteasome inhibition with bortezomib (BTZ) is a validated treatment for relapsed or refractory mantle cell lymphoma (MCL), many patients show resistance to BTZ. However, the molecular mechanism of BTZ resistance in MCL has not been elucidated. In the present study, we investigated BTZ-resistant MCL cells in vitro and in vivo. We demonstrate that BTZ-resistant MCL cells showed highly increased expression of the B-cell receptor (BCR) components CD79A and CD19. Activation of the BCR signaling pathway enhanced the activity of Src family kinases (SFKs), especially Lyn, and downstream kinases PI3K/AKT/mTOR in BTZ-resistant MCL cells. Depletion of CD79A and Lyn significantly reduced several kinase activities involved in PI3K signaling, leading to inhibition of proliferation. In addition, the SFKs inhibitor dasatinib inhibited the proliferation of BTZ-resistant cells, preventing the binding of CD19 with Lyn and PI3K p85. We also verified our findings with the mouse xenograft tumor model. Dasatinib treatment significantly decreased tumor size in the mouse bearing BTZ-resistant MCL cells, but not in the mouse bearing BTZ-sensitive MCL cells. Collectively, our data show that overexpression of the BCR and its activated signaling confers BTZ resistance in MCL cells. Thus, targeting BCR signaling with dasatinib could be a novel therapeutic approach for patients with MCL that has relapsed or is refractory to treatment with BTZ.
authors.affiliation: Laboratory of Experimental Pathology, National Radiation Emergency Medical Center, Seoul, Korea.|Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Seoul, Korea.
authors.forename: Areumnuri
authors.initials: A
authors.lastname: Kim
authors.affiliation: Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Seoul, Korea.
authors.forename: Ki Moon
authors.initials: KM
authors.lastname: Seong
authors.affiliation: Division of Hematology/Oncology, Department of Internal Medicine, Seoul, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kang
authors.affiliation: Laboratory of Experimental Pathology, National Radiation Emergency Medical Center, Seoul, Korea.|Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Seoul, Korea.|Department of Pathology, Korea Institute of Radiological & Medical Science, Seoul, Korea.
authors.forename: Sunhoo
authors.initials: S
authors.lastname: Park
authors.affiliation: Laboratory of Experimental Pathology, National Radiation Emergency Medical Center, Seoul, Korea.|Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Seoul, Korea.|Department of Pathology, Korea Institute of Radiological & Medical Science, Seoul, Korea.
authors.forename: Seung-Sook
authors.initials: SS
authors.lastname: Lee
mesh_terms: D000818:Animals; D018941:Antigens, CD19 / Q000235:genetics / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D000069286:Bortezomib / Q000494:pharmacology*; D051925:CD79 Antigens / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000069439:Dasatinib / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D020522:Lymphoma, Mantle-Cell / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D016513:Mice, SCID; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D019061:src-Family Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D018941:Antigens, CD19; D000970:Antineoplastic Agents; D051925:CD79 Antigens; C497881:CD79A protein, human; D061988:Proteasome Inhibitors; D047428:Protein Kinase Inhibitors; D000069286:Bortezomib; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D046988:Proteasome Endopeptidase Complex; D000069439:Dasatinib
keywords: B cell receptor signaling; Lyn; bortezomib resistance; dasatinib; mantle cell lymphoma