Project description:The precise molecular mechanism of action and targets through which thalidomide and related immunomodulatory drugs (IMiDs) exert their anti-tumor effects remains unclear. We investigated the role of cereblon (CRBN), a primary teratogenic target of thalidomide, in the anti-myeloma activity of IMiDs. CRBN depletion is initially cytotoxic to human myeloma cells but surviving cells with stable CRBN depletion become highly resistant to both lenalidomide and pomalidomide, but not to the unrelated drugs bortezomib, dexamethasone and melphalan. Acquired deletion of CRBN was found to be the primary genetic event differentiating isogenic MM1.S cell lines cultured to be sensitive or resistant to lenalidomide and pomalidomide. Gene expression changes induced by lenalidomide were dramatically suppressed in the presence of CRBN depletion further demonstrating that CRBN is required for lenalidomide activity. Downstream targets of CRBN include interferon regulatory factor 4 (IRF4) previously reported to also be a target of lenalidomide. Patients exposed to and putatively resistant to lenalidomide had lower CRBN levels in paired samples before and after therapy. In summary, CRBN is an essential requirement for IMiD activity, and a possible biomarker for the clinical assessment of anti-myeloma efficacy. We included 15 samples from multiple myeloma cell lines.
Project description:Cereblon (CRBN), a substrate receptor of the E3 ubiquitin ligase complex CRL4CRBN, is the target of the immunomodulatory drugs lenalidomide and pomalidomide. Recently, it was demonstrated that binding of these drugs to CRBN promotes the ubiquitination and subsequent degradation of two common substrates, transcription factors Aiolos and Ikaros. Here we report that the pleiotropic pathway modifier CC-122, a new chemical entity termed pleiotropic pathway modifier binds CRBN and promotes degradation of Aiolos and Ikaros in diffuse large B-cell lymphoma (DLBCL) and T cells in vitro, in vivo and in patients, resulting in both cell autonomous as well as immunostimulatory effects. In DLBCL cell lines, CC-122-induced degradation or shRNA mediated knockdown of Aiolos and Ikaros correlates with increased transcription of interferon stimulated genes (ISGs) independent of interferon α, β, γ production and/or secretion and results in apoptosis in both ABC and GCB-DLBCL cell lines. Our results provide mechanistic insight into the cell of origin independent anti-lymphoma activity of CC-122, in contrast to the ABC subtype selective activity of lenalidomide. Microarray analysis of the OCI-LY10 activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) cell line treated with the compound CC-122 for 18 hours
Project description:The precise molecular mechanism of action and targets through which thalidomide and related immunomodulatory drugs (IMiDs) exert their anti-tumor effects remains unclear. We investigated the role of cereblon (CRBN), a primary teratogenic target of thalidomide, in the anti-myeloma activity of IMiDs. CRBN depletion is initially cytotoxic to human myeloma cells but surviving cells with stable CRBN depletion become highly resistant to both lenalidomide and pomalidomide, but not to the unrelated drugs bortezomib, dexamethasone and melphalan. Acquired deletion of CRBN was found to be the primary genetic event differentiating isogenic MM1.S cell lines cultured to be sensitive or resistant to lenalidomide and pomalidomide. Gene expression changes induced by lenalidomide were dramatically suppressed in the presence of CRBN depletion further demonstrating that CRBN is required for lenalidomide activity. Downstream targets of CRBN include interferon regulatory factor 4 (IRF4) previously reported to also be a target of lenalidomide. Patients exposed to and putatively resistant to lenalidomide had lower CRBN levels in paired samples before and after therapy. In summary, CRBN is an essential requirement for IMiD activity, and a possible biomarker for the clinical assessment of anti-myeloma efficacy. We included two isogenic MM1.S cell lines, which differ in the sensibiligy to lenalidomide. We included MM1.S and MM1.S res, which were sensitive and resistant to lenalidomide, respectively.
Project description:The precise molecular mechanism of action and targets through which thalidomide and related immunomodulatory drugs (IMiDs) exert their anti-tumor effects remains unclear. We investigated the role of cereblon (CRBN), a primary teratogenic target of thalidomide, in the anti-myeloma activity of IMiDs. CRBN depletion is initially cytotoxic to human myeloma cells but surviving cells with stable CRBN depletion become highly resistant to both lenalidomide and pomalidomide, but not to the unrelated drugs bortezomib, dexamethasone and melphalan. Acquired deletion of CRBN was found to be the primary genetic event differentiating isogenic MM1.S cell lines cultured to be sensitive or resistant to lenalidomide and pomalidomide. Gene expression changes induced by lenalidomide were dramatically suppressed in the presence of CRBN depletion further demonstrating that CRBN is required for lenalidomide activity. Downstream targets of CRBN include interferon regulatory factor 4 (IRF4) previously reported to also be a target of lenalidomide. Patients exposed to and putatively resistant to lenalidomide had lower CRBN levels in paired samples before and after therapy. In summary, CRBN is an essential requirement for IMiD activity, and a possible biomarker for the clinical assessment of anti-myeloma efficacy.
Project description:The precise molecular mechanism of action and targets through which thalidomide and related immunomodulatory drugs (IMiDs) exert their anti-tumor effects remains unclear. We investigated the role of cereblon (CRBN), a primary teratogenic target of thalidomide, in the anti-myeloma activity of IMiDs. CRBN depletion is initially cytotoxic to human myeloma cells but surviving cells with stable CRBN depletion become highly resistant to both lenalidomide and pomalidomide, but not to the unrelated drugs bortezomib, dexamethasone and melphalan. Acquired deletion of CRBN was found to be the primary genetic event differentiating isogenic MM1.S cell lines cultured to be sensitive or resistant to lenalidomide and pomalidomide. Gene expression changes induced by lenalidomide were dramatically suppressed in the presence of CRBN depletion further demonstrating that CRBN is required for lenalidomide activity. Downstream targets of CRBN include interferon regulatory factor 4 (IRF4) previously reported to also be a target of lenalidomide. Patients exposed to and putatively resistant to lenalidomide had lower CRBN levels in paired samples before and after therapy. In summary, CRBN is an essential requirement for IMiD activity, and a possible biomarker for the clinical assessment of anti-myeloma efficacy.
Project description:Cereblon (CRBN), a substrate receptor of the E3 ubiquitin ligase complex CRL4CRBN, is the target of the immunomodulatory drugs lenalidomide and pomalidomide. Recently, it was demonstrated that binding of these drugs to CRBN promotes the ubiquitination and subsequent degradation of two common substrates, transcription factors Aiolos and Ikaros. Here we report that the pleiotropic pathway modifier CC-122, a new chemical entity termed pleiotropic pathway modifier binds CRBN and promotes degradation of Aiolos and Ikaros in diffuse large B-cell lymphoma (DLBCL) and T cells in vitro, in vivo and in patients, resulting in both cell autonomous as well as immunostimulatory effects. In DLBCL cell lines, CC-122-induced degradation or shRNA mediated knockdown of Aiolos and Ikaros correlates with increased transcription of interferon stimulated genes (ISGs) independent of interferon α, β, γ production and/or secretion and results in apoptosis in both ABC and GCB-DLBCL cell lines. Our results provide mechanistic insight into the cell of origin independent anti-lymphoma activity of CC-122, in contrast to the ABC subtype selective activity of lenalidomide.
Project description:Plasmablastic lymphoma is a high grade B cell lymphoma with plasmablastic morphology and a terminally differentiated B cell immunophenotype, usually arising in the setting of immunodeficiency and often demonstrating Epstein Barr Virus positivity. The molecular and genetic mechanisms underlying the pathogenesis of PBL are largely unknown. To better understand its pathogenesis, herein we have analyzed global gene expression of PBL and compared that to gene expression profiles of diffuse large B cell lymphoma. While overlaps in transcriptomes between these malignancies were identified, we have shown that the gene expression profile of plasmablastic lymphoma is distinct, demonstrating striking downregulation of B cell receptor signaling genes, BCL6, BCL11A SPI-B, targets of NFKB1, and upregulation of mitochondrial genes, PRMT5, MYC and MYC targets and IL21, implicating these alterations in the pathogenesis of this lymphoma. In addition we show the usefulness of SWAP-70 immunohistochemistry in the differentiation of immunoblastic diffuse large B cell lymphoma and plasmablastic lymphoma. Our findings provide justification for considering plasmablastic lymphoma as a specific lymphoma entity and provide insight into the unique transcriptional aberrations occurring in this high-grade lymphoma.
Project description:Plasmablastic lymphoma is a high grade B cell lymphoma with plasmablastic morphology and a terminally differentiated B cell immunophenotype, usually arising in the setting of immunodeficiency and often demonstrating Epstein Barr Virus positivity. The molecular and genetic mechanisms underlying the pathogenesis of PBL are largely unknown. To better understand its pathogenesis, herein we have analyzed global gene expression of PBL and compared that to gene expression profiles of diffuse large B cell lymphoma. While overlaps in transcriptomes between these malignancies were identified, we have shown that the gene expression profile of plasmablastic lymphoma is distinct, demonstrating striking downregulation of B cell receptor signaling genes, BCL6, BCL11A SPI-B, targets of NFKB1, and upregulation of mitochondrial genes, PRMT5, MYC and MYC targets and IL21, implicating these alterations in the pathogenesis of this lymphoma. In addition we show the usefulness of SWAP-70 immunohistochemistry in the differentiation of immunoblastic diffuse large B cell lymphoma and plasmablastic lymphoma. Our findings provide justification for considering plasmablastic lymphoma as a specific lymphoma entity and provide insight into the unique transcriptional aberrations occurring in this high-grade lymphoma. Expression profiles of 15 plasmablastic lymphomas and 10 diffuse large B-cell lymphomas were obtained using Afymmetrix U133A2 microarrays.