Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL), suggesting that epigenetic regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to histone deacetylase inhibitors (HDACi), one such epigenetic therapy, in order to define mechanisms of response and resistance. Strikingly, using gene expression and metabolic profiling, we found that development of HDACi resistance was associated with differentiation toward a plasmablast-like phenotype. Differentiation correlated with decreased B cell receptor signaling, increased ER stress and activation of the unfolded protein response, and increased sensitivity to proteasome inhibitors. Importantly, we found evidence of differentiation in lymphoma biopsies from patients treated with HDACi. Together, these data show, for the first time, that HDACi are differentiating agents in lymphoma and may be used to prime DLBCL for targeted therapy including proteasome inhibitors. Gene expression in DLBCL cells from tumor biopsies after 15 days panobinostat therapy
Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL), suggesting that epigenetic regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to histone deacetylase inhibitors (HDACi), one such epigenetic therapy, in order to define mechanisms of response and resistance. Strikingly, using gene expression and metabolic profiling, we found that development of HDACi resistance was associated with differentiation toward a plasmablast-like phenotype. Differentiation correlated with decreased B cell receptor signaling, increased ER stress and activation of the unfolded protein response, and increased sensitivity to proteasome inhibitors. Importantly, we found evidence of differentiation in lymphoma biopsies from patients treated with HDACi. Together, these data show, for the first time, that HDACi are differentiating agents in lymphoma and may be used to prime DLBCL for targeted therapy including proteasome inhibitors.
Project description:The BCL6 transcriptional repressor is a critical oncogene in diffuse large B-cell lymphomas (DLBCL). The specific BCL6 inhibitor RI-BPI potently kills DLBCL cells. We find that RI-BPI induces a particular gene expression signature in DLBCL. In order to identify classes of drugs that might synergize with RIBPI we examined the connectivity of this signature and found a strong association with HDAC and Hsp90 inhibitors. This was explained by the discovery that BCL6 directly represses the p300 lysine acetyltransferase and its co-factor BAT3. RI-BPI induced expression of p300 and BAT3, and p300 acetyltransferase activity, resulting in acetylation of p300 targets like p53 and Hsp90. As a consequence, RI-BPI could attenuate Hsp90 chaperone function, similar to the effect of Hsp90 and HDAC inhibitors. Induction of p300 and BAT3 was required for the anti-lymphoma effects of RI-BPI since specific blockade of either protein rescued DLBCL cells from the BCL6 inhibitor. RI-BPI synergistically killed DLBCL cells in combination with HDAC inhibitors (SAHA, TSA and VPA) and Hsp90 inhibitors (17-DMAG and PUH71). The combination of RI-BPI and SAHA, or RI-BPI and PU-H71 potently suppressed or even eradicated human DLBCL in mice. BCL6 repression of EP300 thus provides a basis for rational targeted combinatorial therapy for patients with DLBCL. Direct comparison of gene expression levels in DLBCL cell lines after 24hs of treatment with either a Bcl6 inhibitor peptide or control peptide
Project description:Background: TRAIL (TNF-related apoptosis inducing ligand) exhibits selective proapoptotic activity in multiple tumor types, while sparing normal cells. This selectivity makes TRAIL an attractive therapeutic candidate for cancer patients. However, despite encouraging activity in preclinical models, clinical trials with TRAIL mimetics/death receptor agonists demonstrated insufficient activity, largely due to emerging resistance to these agents. Herein, we investigated the cytotoxic activity of a novel, TRAIL-based chimeric protein AD-051.4 combining TRAIL and VEGFA-derived peptide sequences, in hematological malignancies. We characterize key molecular mechanisms leading to resistance and propose rational pharmacological combinations sensitizing cells to AD-051.4. Methods: Sensitivity of DLBCL, classical Hodgkin lymphoma, (cHL), Burkitt lymphoma (BL) and acute myeloid leukemia (AML) to AD-051.4 was assessed in vitro with MTS assay and apoptosis tests (Annexin V/PI staining). Markers of apoptosis were assessed using immunoblotting, flow cytometry, or fluorogenic caspase cleavage assays. Resistant cell lines were obtained by incubation with increasing doses of AD-O51. Transcriptomic analyses were performed by RNA sequencing. Sensitizing effects of selected pathway modulators (BCL2, dynamin and HDAC inhibitors) were assessed using MTS/apoptosis assays. Results: AD-051.4 exhibited low-nanomolar cytotoxic activity in DLBCL cells, but not in other lymphoid or AML cell lines. AD-051.4 induced death-receptor (DR) mediated, caspase-dependent apoptosis in sensitive DLBCL cells, but not in primary resistant cells. The presence of DRs and caspase 8 in cancer cells was crucial for AD-O51.4-driven apoptosis. To understand the potential mechanisms of resistance in an unbiased way, we engineered AD-051.4-resistant cells and evaluated resistance-associated transcriptomic changes. Resistant cells exhibited changes in the expression of multiple genes and pathways associated with apoptosis, endocytosis and HDAC-dependent epigenetic reprogramming, suggesting potential therapeutic strategies of sensitization to AD-051.4. In subsequent analyses, we demonstrated that HDAC inhibitors, BCL2 inhibitors and endocytosis/dynamin inhibitors sensitized primary resistant DLBCL cells to AD-051.4 Conclusions: Taken together, we identified rational pharmacologic strategies sensitizing cells to AD-051.4, including BCL2, histone deacetylase inhibitors and dynamin modulators. Since AD-051.4 exhibits favorable pharmacokinetics and an acceptable safety profile, further clinical development is expected. Identification of resistance mechanisms in a clinical setting might indicate a personalized pharmacological approach to override the resistance.
Project description:Background/Objectives: The treatment of multiple myeloma (MM) remains a challenge as almost all patients will eventually relapse. Proteasome inhibitors are a cornerstone in the management of MM. Unfortunately, validated biomarkers predict-ing drug response are largely missing. Therefore, we aimed to identify genes associated with drug resistance or sensitization to proteasome inhibitors. Methods: We per-formed genome-wide CRISPR-Cas9 knockout (KO) screens in human KMS-28-BM my-eloma cells to identify genetic determinants associated with resistance or sensitization to proteasome inhibitors. Results: We show that KO of KLF13 and PSMC4 induces drug resistance, while NUDCD2, OSER1 and HERC1 KO cause drug sensitization. Sub-sequently, we focused on top sensitization hit, NUDCD2, which acts as a co-chaperone of Hsp90 to regulate the LIS1/dynein complex. RNA sequencing showed downregula-tion of genes involved in the ERAD pathway and in ER-associated ubiqui-tin-dependent protein catabolic processes in both untreated and carfilzomib-treated NUDCD2 KO cells, suggesting that NUDCD2 depletion alters protein degradation. Furthermore, bortezomib-treated NUDCD2 KO cells showed a decreased expression of genes that have a function in oxidative phosphorylation and the mitochondrial mem-brane, such as Carnitine Palmitoyltransferase 1A (CPT1A). CPT1A catalyzes the up-take of long chain fatty acids into mitochondria. Mitochondrial lipid metabolism has recently been reported as a possible therapeutic target for MM drug sensitivity. Con-clusions: These results contribute to the search of therapeutic targets that can sensitize MM patients to proteasome inhibitors.
Project description:Background/Objectives: The treatment of multiple myeloma (MM) remains a challenge as almost all patients will eventually relapse. Proteasome inhibitors are a cornerstone in the management of MM. Unfortunately, validated biomarkers predict-ing drug response are largely missing. Therefore, we aimed to identify genes associated with drug resistance or sensitization to proteasome inhibitors. Methods: We per-formed genome-wide CRISPR-Cas9 knockout (KO) screens in human KMS-28-BM my-eloma cells to identify genetic determinants associated with resistance or sensitization to proteasome inhibitors. Results: We show that KO of KLF13 and PSMC4 induces drug resistance, while NUDCD2, OSER1 and HERC1 KO cause drug sensitization. Sub-sequently, we focused on top sensitization hit, NUDCD2, which acts as a co-chaperone of Hsp90 to regulate the LIS1/dynein complex. RNA sequencing showed downregula-tion of genes involved in the ERAD pathway and in ER-associated ubiqui-tin-dependent protein catabolic processes in both untreated and carfilzomib-treated NUDCD2 KO cells, suggesting that NUDCD2 depletion alters protein degradation. Furthermore, bortezomib-treated NUDCD2 KO cells showed a decreased expression of genes that have a function in oxidative phosphorylation and the mitochondrial mem-brane, such as Carnitine Palmitoyltransferase 1A (CPT1A). CPT1A catalyzes the up-take of long chain fatty acids into mitochondria. Mitochondrial lipid metabolism has recently been reported as a possible therapeutic target for MM drug sensitivity. Con-clusions: These results contribute to the search of therapeutic targets that can sensitize MM patients to proteasome inhibitors.
Project description:Background/Objectives: The treatment of multiple myeloma (MM) remains a challenge as almost all patients will eventually relapse. Proteasome inhibitors are a cornerstone in the management of MM. Unfortunately, validated biomarkers predict-ing drug response are largely missing. Therefore, we aimed to identify genes associated with drug resistance or sensitization to proteasome inhibitors. Methods: We per-formed genome-wide CRISPR-Cas9 knockout (KO) screens in human KMS-28-BM my-eloma cells to identify genetic determinants associated with resistance or sensitization to proteasome inhibitors. Results: We show that KO of KLF13 and PSMC4 induces drug resistance, while NUDCD2, OSER1 and HERC1 KO cause drug sensitization. Sub-sequently, we focused on top sensitization hit, NUDCD2, which acts as a co-chaperone of Hsp90 to regulate the LIS1/dynein complex. RNA sequencing showed downregula-tion of genes involved in the ERAD pathway and in ER-associated ubiqui-tin-dependent protein catabolic processes in both untreated and carfilzomib-treated NUDCD2 KO cells, suggesting that NUDCD2 depletion alters protein degradation. Furthermore, bortezomib-treated NUDCD2 KO cells showed a decreased expression of genes that have a function in oxidative phosphorylation and the mitochondrial mem-brane, such as Carnitine Palmitoyltransferase 1A (CPT1A). CPT1A catalyzes the up-take of long chain fatty acids into mitochondria. Mitochondrial lipid metabolism has recently been reported as a possible therapeutic target for MM drug sensitivity. Con-clusions: These results contribute to the search of therapeutic targets that can sensitize MM patients to proteasome inhibitors.
Project description:Histone deacetylase (HDAC) inhibition has been shown in previous studies to disrupt the synovial sarcoma oncoprotein complex, resulting in apoptosis. To understand the molecular effects of HDAC inhibition, RNA-Seq transcriptome analysis was undertaken in six human synovial sarcoma cell lines. HDAC inhibition induced pathways of cell cycle arrest, neuronal differentiation and response to oxygen-containing species, effects also observed in other cancers treated with this class of drugs. More specific to synovial sarcoma, polycomb-group targets were reactivated including tumor suppressor CDKN2A, and pro-apoptotic transcriptional patterns were induced. Functional analyses revealed that ROS-mediated FOXO activation and pro-apoptotic factors BIK, BIM and BMF were important to apoptosis induction following HDAC-inhibition in synovial sarcoma
Project description:The BCL6 transcriptional repressor is a critical oncogene in diffuse large B-cell lymphomas (DLBCL). The specific BCL6 inhibitor RI-BPI potently kills DLBCL cells. We find that RI-BPI induces a particular gene expression signature in DLBCL. In order to identify classes of drugs that might synergize with RIBPI we examined the connectivity of this signature and found a strong association with HDAC and Hsp90 inhibitors. This was explained by the discovery that BCL6 directly represses the p300 lysine acetyltransferase and its co-factor BAT3. RI-BPI induced expression of p300 and BAT3, and p300 acetyltransferase activity, resulting in acetylation of p300 targets like p53 and Hsp90. As a consequence, RI-BPI could attenuate Hsp90 chaperone function, similar to the effect of Hsp90 and HDAC inhibitors. Induction of p300 and BAT3 was required for the anti-lymphoma effects of RI-BPI since specific blockade of either protein rescued DLBCL cells from the BCL6 inhibitor. RI-BPI synergistically killed DLBCL cells in combination with HDAC inhibitors (SAHA, TSA and VPA) and Hsp90 inhibitors (17-DMAG and PUH71). The combination of RI-BPI and SAHA, or RI-BPI and PU-H71 potently suppressed or even eradicated human DLBCL in mice. BCL6 repression of EP300 thus provides a basis for rational targeted combinatorial therapy for patients with DLBCL.
Project description:Bortezomib (BTZ), Carfilzomib (CFZ) and Ixazomib (IXA) are proteasome inhibitors (PI) approved for Multiple Myeloma (MM) treatment. By design, they all target the rate-limiting proteasome beta 5 (B5) subunit. CFZ treatment increases the survival of patients with relapsed/refractory MM compared to BTZ but is associated with heart failure not commonly observed for BTZ. The molecular basis for CFZ-induced cardiotoxicity is poorly understood. We time to investigate the transcriptomic effects of acute proteasome inhibition in the murine heart.