title: Expression of immunoproteasome genes is regulated by cell-intrinsic and -extrinsic factors in human cancers.
abstract: Based on transcriptomic analyses of thousands of samples from The Cancer Genome Atlas, we report that expression of constitutive proteasome (CP) genes (PSMB5, PSMB6, PSMB7) and immunoproteasome (IP) genes (PSMB8, PSMB9, PSMB10) is increased in most cancer types. In breast cancer, expression of IP genes was determined by the abundance of tumor infiltrating lymphocytes and high expression of IP genes was associated with longer survival. In contrast, IP upregulation in acute myeloid leukemia (AML) was a cell-intrinsic feature that was not associated with longer survival. Expression of IP genes in AML was IFN-independent, correlated with the methylation status of IP genes, and was particularly high in AML with an M5 phenotype and/or MLL rearrangement. Notably, PSMB8 inhibition led to accumulation of polyubiquitinated proteins and cell death in IPhighbut not IPlowAML cells. Co-clustering analysis revealed that genes correlated with IP subunits in non-M5 AMLs were primarily implicated in immune processes. However, in M5 AML, IP genes were primarily co-regulated with genes involved in cell metabolism and proliferation, mitochondrial activity and stress responses. We conclude that M5 AML cells can upregulate IP genes in a cell-intrinsic manner in order to resist cell stress.
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Rouette
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.|Department of Computer Science and Operations Research, Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Assya
authors.initials: A
authors.lastname: Trofimov
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Haberl
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Boucher
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.|Division of Hematology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.|Quebec Leukemia Cell Bank, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.
authors.forename: Vincent-Philippe
authors.initials: VP
authors.lastname: Lavallée
authors.affiliation: Division of Hematology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.|Quebec Leukemia Cell Bank, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.
authors.forename: Giovanni
authors.initials: G
authors.lastname: D'Angelo
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.|Division of Hematology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.|Quebec Leukemia Cell Bank, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.
authors.forename: Josée
authors.initials: J
authors.lastname: Hébert
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.|Division of Hematology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.|Quebec Leukemia Cell Bank, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.
authors.forename: Guy
authors.initials: G
authors.lastname: Sauvageau
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Computer Science and Operations Research, Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lemieux
authors.affiliation: Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada.|Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.|Division of Hematology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.
authors.forename: Claude
authors.initials: C
authors.lastname: Perreault