Project description:The aim of this study was to identify EZH2 targets in myeloid malignancies. RNA samples from control F-36P, MOLM-13 and OCI-M2 cells (secondary AML after MDS; EZH2 wild type) treated with random shRNA (n = 4, each) and test F-36P, MOLM-13 and OCI-M2 cells treated with either one of two EZH2-targeting shRNAs (n = 4, each) were screened for differential gene expression. RNA from EZH2 wild type (n = 12) and mutant (n = 12) MDS/MPN patients was also analyzed by microarray transcriptome analysis.
Project description:Two mice in which luciferase-positive LOUCY ETP-ALL cells were xenografted were treated with either vehicle or ABT-199 (50 mg/kg) for 11 days. Afterwards, single cells suspensions were made from bone marrow and spleen of both mice for 10x Genomics scRNA-seq. Following quality control, a total of 13,681 spleen cells and 11,442 bone marrow cells of the control mouse and 15,955 spleen cells and 9,443 bone marrow cells of the ABT 199 treated mouse were processed for further analysis. Our data show that ABT-199 triggers transcriptional changes in T-cell differentiation genes in leukemic cells obtained from the spleen microenvironment. These results are in line with our previous findings that mature typical T-ALL are resistant to ABT-199.
Project description:Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) are the most prevalent B-lymphocyte neoplasms in which abnormal activation of the Bruton’s tyrosine kinase (BTK)–mediated B-cell receptor (BCR) signaling pathway contributes to pathogenesis. Ibrutinib is an oral covalent BTK inhibitor that has shown some efficacy in both indications. To improve ibrutinib efficacy through combination therapy, we first investigated differential gene expression in parental and ibrutinib-resistant cell lines to better understand the mechanisms of resistance. Ibrutinib-resistant TMD8 cells had higher BCL2 gene expression and increased sensitivity to ABT-199, a BCL-2 inhibitor. Consistently, clinical samples from ABC-DLBCL patients who experienced poorer response to ibrutinib had higher BCL2 gene expression. We further demonstrated synergistic growth suppression by ibrutinib and ABT-199 in multiple ABC-DLBCL, GCB-DLBCL, and FL lymphoma cell lines. The combination of both drugs also reduced colony formation, increased apoptosis, and inhibited tumor growth in a TMD8 xenograft model. A synergistic combination effect was also found in ibrutinib-resistant cells generated by either genetic mutation or drug treatment. Together, these findings suggest a potential clinical benefit from ibrutinib and ABT-199 combination therapy.
Project description:Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) are the most prevalent B-lymphocyte neoplasms in which abnormal activation of the Bruton’s tyrosine kinase (BTK)–mediated B-cell receptor (BCR) signaling pathway contributes to pathogenesis. Ibrutinib is an oral covalent BTK inhibitor that has shown some efficacy in both indications. To improve ibrutinib efficacy through combination therapy, we first investigated differential gene expression in parental and ibrutinib-resistant cell lines to better understand the mechanisms of resistance. Ibrutinib-resistant TMD8 cells had higher BCL2 gene expression and increased sensitivity to ABT-199, a BCL-2 inhibitor. Consistently, clinical samples from ABC-DLBCL patients who experienced poorer response to ibrutinib had higher BCL2 gene expression. We further demonstrated synergistic growth suppression by ibrutinib and ABT-199 in multiple ABC-DLBCL, GCB-DLBCL, and FL lymphoma cell lines. The combination of both drugs also reduced colony formation, increased apoptosis, and inhibited tumor growth in a TMD8 xenograft model. A synergistic combination effect was also found in ibrutinib-resistant cells generated by either genetic mutation or drug treatment. Together, these findings suggest a potential clinical benefit from ibrutinib and ABT-199 combination therapy.
Project description:RNA-sequencing was performed to evaluate gene expression changes between ABT-199 (venetoclax) sensitive and resistant matched diffuse large B cell lymphoma cell lines
Project description:Drug-tolerant “persister” cells underlie the emergence of drug-resistant clones and allow residual tumors to survive therapy; thus, represent an attractive therapeutic target to mitigate relapse. With the promising outcome, yet some resistance cases surfaced after the approval of venetoclax (ABT-199), we defined a novel invasive drug resistance mechanism induced by Bcl2 inhibitor via examining the evolution of drug tolerant persister clones generated with ABT-199 treatment. The ABT-199 drug-tolerant persister cells showed genetic alteration by losing the copy number at 18q21 paralleled with BCL2, PMAIP1 and TCF4 gene downregulation. The persister status are generated through major enhancer-remodeling mediated transcriptional activation of the super enhancer, which offered unique opportunity for overcoming the drug resistance. The insight of major determinant for ABT-199 persistence evolution identified the molecular vulnerability in Bcl2 inhibitor resistant lymphoma cells through CDK7 pathway inhibition. The combined CDK7 and BCL2 inhibition was found to be more effective against ABT-199 persistence ex vivo and in vivo rather than the parental line, and CDK7 inhibition eliminated the persister phenotype by blocking dynamic active enhancer formation to further prevent the evolution of drug resistance. Together, these studies unified genetic alteration and non-mutational adaptive response as a drug resistance mechanism, more importantly, demonstrated a rationale for transcriptional inhibition-based combination strategies to prevent and overcome drug resistance in B-cell malignancies.
Project description:Drug-tolerant “persister” cells underlie the emergence of drug-resistant clones and allow residual tumors to survive therapy; thus, represent an attractive therapeutic target to mitigate relapse. With the promising outcome, yet some resistance cases surfaced after the approval of venetoclax (ABT-199), we defined a novel invasive drug resistance mechanism induced by Bcl2 inhibitor via examining the evolution of drug tolerant persister clones generated with ABT-199 treatment. The ABT-199 drug-tolerant persister cells showed genetic alteration by losing the copy number at 18q21 paralleled with BCL2, PMAIP1 and TCF4 gene downregulation. The persister status are generated through major enhancer-remodeling mediated transcriptional activation of the super enhancer, which offered unique opportunity for overcoming the drug resistance. The insight of major determinant for ABT-199 persistence evolution identified the molecular vulnerability in Bcl2 inhibitor resistant lymphoma cells through CDK7 pathway inhibition. The combined CDK7 and BCL2 inhibition was found to be more effective against ABT-199 persistence ex vivo and in vivo rather than the parental line, and CDK7 inhibition eliminated the persister phenotype by blocking dynamic active enhancer formation to further prevent the evolution of drug resistance. Together, these studies unified genetic alteration and non-mutational adaptive response as a drug resistance mechanism, more importantly, demonstrated a rationale for transcriptional inhibition-based combination strategies to prevent and overcome drug resistance in B-cell malignancies.