Proteasome Inhibition by Bortezomib Increases IL-8 Expression in Androgen-Independent Prostate Cancer Cells: The Role of IKKα
| Autor: | Bipradeb Singha, Shannon Sanacora, Sitharam Ramaswami, Sai Aung Phyo, Himavanth R. Gatla, Tzu-Pei Chang, Ivana Vancurova, Subrata Manna |
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| Rok vydání: | 2013 |
| Předmět: |
Male
Chromatin Immunoprecipitation Proteasome Endopeptidase Complex Blotting Western Immunology Antineoplastic Agents Enzyme-Linked Immunosorbent Assay IκB kinase Biology Real-Time Polymerase Chain Reaction Transfection Article Proinflammatory cytokine Bortezomib Prostate cancer DU145 Cell Line Tumor medicine Humans Immunology and Allergy Interleukin 8 RNA Small Interfering Interleukin-8 Prostatic Neoplasms medicine.disease Boronic Acids I-kappa B Kinase Proteasome Pyrazines Cancer research medicine.drug |
| Zdroj: | The Journal of Immunology. 191:2837-2846 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.1300895 |
| Popis: | Expression of the proinflammatory and proangiogenic chemokine IL-8, which is regulated at the transcriptional level by NF-κB, is constitutively increased in androgen-independent metastatic prostate cancer and correlates with poor prognosis. Inhibition of NF-κB–dependent transcription was used as an anticancer strategy for the development of the first clinically approved 26S proteasome inhibitor, bortezomib (BZ). Even though BZ has shown remarkable antitumor activity in hematological malignancies, it has been less effective in prostate cancer and other solid tumors; however, the mechanisms have not been fully understood. In this article, we report that proteasome inhibition by BZ unexpectedly increases IL-8 expression in androgen-independent prostate cancer PC3 and DU145 cells, whereas expression of other NF-κB–regulated genes is inhibited or unchanged. The BZ-increased IL-8 expression is associated with increased in vitro p65 NF-κB DNA binding activity and p65 recruitment to the endogenous IL-8 promoter. In addition, proteasome inhibition induces a nuclear accumulation of IκB kinase (IKK)α, and inhibition of IKKα enzymatic activity significantly attenuates the BZ-induced p65 recruitment to IL-8 promoter and IL-8 expression, demonstrating that the induced IL-8 expression is mediated, at least partly, by IKKα. Together, these data provide the first evidence, to our knowledge, for the gene-specific increase of IL-8 expression by proteasome inhibition in prostate cancer cells and suggest that targeting both IKKα and the proteasome may increase BZ effectiveness in treatment of androgen-independent prostate cancer. |
| Databáze: | OpenAIRE |
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