title: Bortezomib augments lymphocyte stimulatory cytokine signaling in the tumor microenvironment to sustain CD8+T cell antitumor function.
abstract: Tumor-induced immune tolerance poses a major challenge for therapeutic interventions aimed to manage cancer. We explored approaches to overcome T-cell suppression in murine breast and kidney adenocarcinomas, and lung fibrosarcoma expressing immunogenic antigens. We observed that treatment with a reversible proteasome inhibitor bortezomib (1 mg/kg body weight) in tumor-bearing mice significantly enhanced the expression of lymphocyte-stimulatory cytokines IL-2, IL-12, and IL-15. Notably, bortezomib administration reduced pulmonary nodules of mammary adenocarcinoma 4T1.2 expressing hemagglutinin (HA) model antigen (4T1HA) in mice. Neutralization of IL-12 and IL-15 cytokines with a regimen of blocking antibodies pre- and post-adoptive transfer of low-avidity HA518-526-specific CD8+T-cells following intravenous injection of 4T1HA cells increased the number of pulmonary tumor nodules. This neutralization effect was counteracted by the tumor metastasis-suppressing action of bortezomib treatments. In bortezomib-treated 4T1HA tumor-bearing mice, CD4+T-cells showed increased IL-2 production, CD11c+ dendritic cells showed increased IL-12 and IL-15 production, and HA-specific activated CD8+T-cells showed enhanced expression of IFNγ, granzyme-B and transcription factor eomesodermin. We also noted a trend of increased expression of IL-2, IL-12 and IL-15 receptors as well as increased phosphorylation of STAT5 in tumor-infiltrating CD8+T-cells following bortezomib treatment. Furthermore, bortezomib-treated CD8+T-cells showed increased phosphorylation of mitogen-activated protein kinase p38, and Akt, which was abrogated by phosphatidylinositide 3-kinase (PI3K) inhibitor. These data support the therapeutic potential of bortezomib in conjunction with other immunotherapies to augment the strength of convergent signals from CD8+T-cell signaling molecules including TCR, cytokine receptors and downstream PI3K/Akt/STAT5 pathways to sustain CD8+T-cell effector function in the tumor microenvironment.
authors.affiliation: Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.|Department of Microbiology and Immunology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.|School of Graduate Studies and Research, Meharry Medical College, Nashville, Tennessee, USA.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Pellom
authors.affiliation: Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.
authors.forename: Duafalia F
authors.initials: DF
authors.lastname: Dudimah
authors.affiliation: Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.
authors.forename: Menaka C
authors.initials: MC
authors.lastname: Thounaojam
authors.affiliation: Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.
authors.forename: Roman V
authors.initials: RV
authors.lastname: Uzhachenko
authors.affiliation: Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Singhal
authors.affiliation: Tennessee Valley Healthcare System, Nashville, Tennessee, USA.|Department of Veterans Affairs, Nashville, Tennessee, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.|Host-Tumor Interactions Research Program, Vanderbilt-Ingram Comprehensive Cancer Center, Vanderbilt University, Nashville, Tennessee, USA.|Vanderbilt Center for Immunobiology, Vanderbilt University, Nashville, Tennessee, USA.|Vanderbilt Center for Translational and Clinical Immunology, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Ann
authors.initials: A
authors.lastname: Richmond
authors.affiliation: Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.|School of Graduate Studies and Research, Meharry Medical College, Nashville, Tennessee, USA.|Host-Tumor Interactions Research Program, Vanderbilt-Ingram Comprehensive Cancer Center, Vanderbilt University, Nashville, Tennessee, USA.|Vanderbilt Center for Immunobiology, Vanderbilt University, Nashville, Tennessee, USA.|Vanderbilt Center for Translational and Clinical Immunology, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Shanker
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000069286:Bortezomib / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D045744:Cell Line, Tumor; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005260:Female; D005354:Fibrosarcoma / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D007680:Kidney Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D016246:Lymphocytes, Tumor-Infiltrating / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D018121:Receptors, Cytokine / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019139:Tumor Escape / Q000187:drug effects; D059016:Tumor Microenvironment
chemical_list: D000970:Antineoplastic Agents; D016207:Cytokines; D061988:Proteasome Inhibitors; D018121:Receptors, Cytokine; D050799:STAT5 Transcription Factor; D000069286:Bortezomib; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D046988:Proteasome Endopeptidase Complex
keywords: CD8+ T cells; adoptive cell therapy; cancer immunotherapy; immunosuppression; proteasome inhibition