Halting pro-survival autophagy by TGFβ inhibition in bone marrow fibroblasts overcomes bortezomib resistance in multiple myeloma patients.
Bortezomib (bort) has improved overall survival in patients with multiple myeloma (MM), but the majority of them develop drug resistance. In this study, we demonstrate that bone marrow (BM) fibroblasts (cancer-associated fibroblasts; CAFs) from bort-resistant patients are insensitive to bort and protect the RPMI8226 and patients' plasma cells against bort-induced apoptosis. Bort triggers CAFs to produce high levels of interleukin (IL)-6, IL-8, insulin-like growth factor (IGF)-1 and transforming growth factor (TGF) β. Proteomic studies on CAFs demonstrate that bort resistance parallels activation of oxidative stress and pro-survival autophagy. Indeed, bort induces reactive oxygen species in bort-resistant CAFs and activates autophagy by increasing light chain 3 protein (LC3)-II and inhibiting p62 and phospho-mammalian target of rapamycin. The small-interfering RNA knockdown of Atg7, and treatment with 3-methyladenine, restores bort sensitivity in bort-resistant CAFs and produces cytotoxicity in plasma cells co-cultured with CAFs. In the syngeneic 5T33 MM model, bort-treatment induces the expansion of LC3-II(+) CAFs. TGFβ mediates bort-induced autophagy, and its blockade by LY2109761, a selective TβRI/II inhibitor, reduces the expression of p-Smad2/3 and LC3-II and induces apoptosis in bort-resistant CAFs. A combination of bort and LY2109761 synergistically induces apoptosis of RPMI8226 co-cultured with bort-resistant CAFs. These data define a key role for CAFs in bort resistance of plasma cells and provide the basis for a novel targeted therapeutic approach.
Department of Biomedical Sciences and Human Oncology, General Pathology Unit, University of Bari Medical School, Bari, Italy.
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MA
Frassanito
Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
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De Veirman
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Desantis
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Di Marzo
Department of Biological and Environmental Sciences and Technologies, University of Salento, Laboratory of Clinical Proteomics, "Giovanni Paolo II" Hospital, ASL-Lecce, Italy.
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Vergara
Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari Medical School, Bari, Italy.
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Ruggieri
Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari Medical School, Bari, Italy.
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Annese
Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari Medical School, Bari, Italy.
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http://orcid.org/0000-0003-4768-8431
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Nico
Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
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Menu
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Catacchio
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Ria
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Racanelli
Department of Biological and Environmental Sciences and Technologies, University of Salento, Laboratory of Clinical Proteomics, "Giovanni Paolo II" Hospital, ASL-Lecce, Italy.
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Maffia
Department of Haematology, Businco Hospital, Cagliari, Italy.
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Angelucci
Department of Haematology, Businco Hospital, Cagliari, Italy.
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Derudas
Department of Biomedical Sciences and Human Oncology, General Pathology Unit, University of Bari Medical School, Bari, Italy.
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Fumarulo
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Dammacco
Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari Medical School, Bari, Italy.
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Ribatti
Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
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K
Vanderkerken
Department of Biomedical Sciences and Human Oncology, Unit of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
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Vacca
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001343:Autophagy / Q000187:drug effects; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D000069286:Bortezomib / Q000494:pharmacology*; D004338:Drug Combinations; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D010950:Plasma Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D061251:Primary Cell Culture; D011720:Pyrazoles / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D016019:Survival Analysis; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D004338:Drug Combinations; C530108:LY2109761; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; C118585:P62 protein, human; D011720:Pyrazoles; D011758:Pyrroles; D016601:RNA-Binding Proteins; D016212:Transforming Growth Factor beta; D000069286:Bortezomib; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases