Transcriptional response to standard AML drugs identifies synergistic combinations
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ABSTRACT: Unlike genomic alterations, gene expression profiles have not been widely used to refine cancer therapies. We analyzed transcriptional changes in acute myeloid leukemia (AML) cell lines in response to standard first-line AML drugs cytarabine and daunorubicin by means of RNA sequencing. Those changes were highly cell- and treatment-specific. By comparing the changes unique to treatment-sensitive and treatment-resistant AML cells, we enriched for treatment-relevant genes. Those genes were associated with drug response-specific pathways, including calcium ion-dependent exocytosis and chromatin remodeling. Pharmacological mimicking of those changes using EGFR and MEK inhibitors enhanced the response to daunorubicin with minimum standalone cytotoxicity. The synergistic response was observed even in the cell lines beyond those used for the discovery, including a primary AML sample. Additionally, publicly available cytotoxicity data confirmed the synergistic effect of EGFR inhibitors in combination with daunorubicin in all 60 investigated cancer cell lines. In conclusion, we demonstrate the utility of treatment-evoked gene expression changes to formulate rational drug combinations. This approach could improve the standard AML therapy, especially in older patients.
Project description:Acute myeloid leukemia (AML) is an aggressive malignancy of hematopoietic cells. Despite recent approvals of targeted drugs, chemotherapy with cytosine arabinoside (araC) and an anthracycline like daunorubicin remains an important pillar of treatment. In a previous work, we have shown that MTSS1 is down-regulated at relapse compared to diagnosis of AML and its down-regulation was previously implicated in aggressiveness of solid tumors. Our results showed that MTSS1 expression was regulated by methylation and reduced by araC and daunorubicin. Experimental down-regulation rendered human AML cell lines more resistant to araC, daunorubicin, and eight additional drugs. In contrast, venetoclax, a BCL2 inhibitor, was more effective towards cells with low MTSS1 expression. A CRISPR/Cas9-mediated knock-out of the MTSS1 gene was used to generate insight into the molecular changes induced by the down-regulation of MTSS1. The knock-out led to the deregulation of > 900 genes which included numerous target genes of transcription factors with a confirmed role in hematopoiesis and AML. A gene ontology analysis of the differentially expressed genes revealed that genes linked to transcription, cell cycle, and immune response were strongly affect. In summary, down-regulation of MTSS1 is associated with primary and secondary chemotherapy resistance in AML. In experimental models, it confers refractoriness to several cytotoxic drugs, yet sensitizes cells to venetoclax, pointing towards ways to overcome therapy resistance in MTSS1low AML.
Project description:Acute Myeloid Leukemia (AML) is the most common and aggressive form of acute leukemia, with a 5-year survival rate of just 24%. Over a third of all AML patients harbor activating mutations in kinases, such as the receptor tyrosine kinases FLT3 and KIT. FLT3 and KIT mutations are associated with poor clinical outcomes and lower remission rates in response to standard-of-care chemotherapy. We have recently identified that the core kinase of the non-homologous end joining DNA repair pathway, DNA-PK, is activated downstream of FLT3; and targeting DNA-PK sensitized FLT3-mutant AML cells to standard-of-care therapies. Herein, we investigated DNA-PK as a possible therapeutic vulnerability in KIT mutant AML, using isogenic FDC-P1 myeloid progenitor cell lines transduced with an empty vector or oncogenic mutant KIT (V560G, D816V). Targeted quantitative phosphoproteomic profiling identified phosphorylation of DNA-PK at threonine 2599 in KIT mutant cells, indicative of DNA-PK activation. Accordingly, proliferation assays revealed that KIT mutant FDC-P1 cells were more sensitive to the DNA-PK inhibitors M3814 or NU7441, compared to empty vector controls. DNA-PK inhibition combined with inhibition of KIT signaling via using the kinase inhibitors dasatinib or ibrutinib, or the protein phosphatase 2A activators FTY720 or AAL(S), led to synergistic cell death. Discovery phosphoproteomic analysis of KIT-D816V cells revealed that dasatinib single-agent treatment inhibited ERK1 activity, and M3814 single-agent treatment inhibited Akt/mTOR activity. The combination of dasatinib and M3814 treatment inhibited both ERK/MAPK and Akt/mTOR activity, and induced synergistic inhibition of phosphorylation of transcription regulators including MYC and MYB. This study provides insight into the oncogenic pathways regulated by DNA-PK beyond its canonical role in DNA repair, and demonstrates that DNA-PK is a promising novel therapeutic target for KIT mutant cancers.
Project description:Myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) are diseases of abnormal hematopoietic differentiation with aberrant epigenetic alterations. Azacitidine (AZA) is a DNA methyltransferase inhibitor (DNMTi) widely used to treat MDS and AML, yet the impact of AZA on the cell surface proteome has not been defined. To identify potential therapeutic targets for use in combination with AZA in AML patients, we investigated the effects of AZA treatment on four AML cell lines representing different stages of differentiation. The effect of AZA treatment on these cell lines was characterized at three levels: the DNA methylome, the transcriptome, and the cell surface proteome. Untreated AML cell lines showed substantial overlap at all three omics level; however, while AZA treatment globally reduced DNA methylation in all cell lines, changes in the transcriptome and surface proteome were subtle and differed among the cell lines. Transcriptome analysis identified five commonly up-regulated coding genes upon AZA treatment in all four cell lines, TRPM4 being the only gene encoding a surface protein, and surface proteomics analysis found no commonly regulated proteins. Gene Set Enrichment Analysis (GSEA) of differentially-regulated RNA and surface proteins showed a decrease in metabolism pathways and an increase in immune defense response pathways. As such, AZA treatment led to diverse effects at the individual gene and protein level but converged to common responses at the pathway level. Given the heterogeneous responses in the four cell lines, we discuss potential therapeutic strategies for AML in combinations with AZA.
Project description:The drug efflux pump ABCB1 is a key driver of chemoresistance, and high expression predicts for treatment failure in acute myeloid leukemia (AML). We show that both acute and chronic exposure of leukemia cells to daunorubicin activates an integrated stress response-like transcriptional program to induce ABCB1 through remodeling and dynamic activation of an ATF4-bound, stress-responsive enhancer. In primary human AML, stress-responsive ABCB1 enhancers are accessible and acetylated, and exposure of fresh blast cells to daunorubicin induces ABCB1 in a dose-dependent manner. Dynamic induction of ABCB1 by diverse stressors, including chemotherapy, facilitates escape of leukemia cells from targeted third-generation ABCB1 inhibition. Stress-induced up regulation of ABCB1 is mitigated by combined use of pharmacologic inhibitors U0126 and ISRIB, which inhibit stress signaling.
Project description:The drug efflux pump ABCB1 is a key driver of chemoresistance, and high expression predicts for treatment failure in acute myeloid leukemia (AML). We show that both acute and chronic exposure of leukemia cells to daunorubicin activates an integrated stress response-like transcriptional program to induce ABCB1 through remodeling and dynamic activation of an ATF4-bound, stress-responsive enhancer. In primary human AML, stress-responsive ABCB1 enhancers are accessible and acetylated, and exposure of fresh blast cells to daunorubicin induces ABCB1 in a dose-dependent manner. Dynamic induction of ABCB1 by diverse stressors, including chemotherapy, facilitates escape of leukemia cells from targeted third-generation ABCB1 inhibition. Stress-induced up regulation of ABCB1 is mitigated by combined use of pharmacologic inhibitors U0126 and ISRIB, which inhibit stress signaling.
Project description:Recently approved cancer drugs remain out-of-reach to most patients due to prohibitive costs and only few produce clinically meaningful benefits. An untapped alternative is to enhance the efficacy and safety of existing cancer treatments. We hypothesized that the response to topoisomerase II poisons, the most successful group of cancer drugs, can be improved by considering treatment-associated transcript levels, taken as surrogates for protein expression. To this end, we analyzed transcriptomes from Acute Myeloid Leukemia (AML) cell lines treated with the topoisomerase II poison etoposide. Using complementary criteria of co-regulation within networks and of essentiality for cell survival, we identified and functionally confirmed 11 druggable drivers of etoposide cytotoxicity. Drivers with pre-treatment expression predicting etoposide response (e.g. PARP9) generally synergized with the drug. Drivers repressed by etoposide (e.g. PLK1) displayed standalone cytotoxicity. Drivers, whose modulation evoked etoposide-like gene expression changes (e.g. mTOR), were cytotoxic both alone and in combination with etoposide. In summary, both pre-treatment gene expression and treatment-driven changes contribute to the cell killing effect of etoposide. Inhibitors of protein products of the involved genes can be used to enhance the efficacy of etoposide. This strategy can be used to identify combination partners or even replacements for other classical anticancer drugs, especially those interfering with DNA integrity and transcription.
Project description:Wide inter-individual variation in terms of outcome and toxic side effects of treatment exist among patients with AML receiving chemotherapy with cytarabine (Ara-C) and daunorubicin (Dnr). Drug resistance and relapse are considered major causes of treatment failure. Gene expression profiling was undertaken to address possible mechanisms of Ara-C/Dnr resistance. Based on ex vivo Ara-C cytotoxicity at diagnosis, Ara-C sensitive (IC50 <3uM AraC) and Dnr sensitive samples (IC50 < 0.5 uM) (5 samples each) were included for microarray analysis. These were compared with the samples which were drug resistant ex vivo at diagnosis. Our microarray experiment resulted in indentifying differentially expressed genes under ex vivo Ara-C sensitive as well as Dnr sensitive samples compared to ex vivo Drug resistant samples. One-color experiment,Organism: Homo sapiens, Custom Human Whole Genome 8x60k Array designed by Genotypic Technology Private Limited (AMADID: 27114), Labeling kit: Agilent Quick-Amp labeling Kit (p/n5190-0442)
Project description:Acute promyelocytic leukaemia (APL) can be cured by the co-administration of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA). These small molecules relieve the differentiation blockade of the cancerous promyelocytes and trigger their maturation into functional neutrophils, which are physiologically primed for apoptosis. This normalization therapy uses low dose treatments and represents a compelling alternative to cytotoxic anticancer chemotherapy. However, the serendipitous discovery of this combination treatment prevented the establishment of methodologies to screen for novel combination treatments consisting of inducers of differentiation and other metallopharmaceuticals. Here, we present an experimental framework that enables interrogating the suitability, directionality and extent of normalization of novel combination treatments. Since the endpoint of this anticancer treatment is remodelling of cancer phenotypes, this approach requires a mechanism-driven understanding of the drug-induced cellular adaptions along the path to mature neutrophils. For this purpose, label-free quantification proteomics is used to probe the proteome changes upon differentiation and metal(-loid) treatment on the molecular level in a panel of ATRA-responsive and ATRA-non-responsive acute myeloid leukaemia (AML) cell lines, including APL. The induction of differentiation was confirmed by the up-regulation of canonical surface markers (e.g. CD11β) and validated by flow cytometry. The regulation of key transcription factors in this panel of AML cell lines reflects their position in the myeloid differentiation cascade (e.g. SPI1, GFI-1 and CEBPE). The additive/synergistic contributions of ATO to the combination treatment were thoroughly characterized and include changes in metabolic activities, as well as protein signatures related to management of reactive oxygen species and an integrated stress response. The latter two are also characteristic for the organoruthenium-based drug candidate plecstatin-1, which was recently shown to modulate the scaffold protein plectin. The combination of differentiation-induction and plecstatin-1 treatment featured a striking similarity in the responsiveness of the AML cancer cells compared to ATO+ATRA. It turned out to be at least equivalent in the regulation of key processes underlying normalization therapy in AML with granulocytic maturation. By exploiting response patterns of AML cancer cells induced by the ATO+ATRA combination treatment, this approach may allow identifying novel small molecule combinations, which may have the potential to achieve normalization and thus therapeutic benefit beyond APL.
Project description:The study was designed to identify the molecular changes that occur in EGFR mutant NSCLCs that become resistant to TKI by transforming to SCLC. Tyrosine kinase inhibitors (TKIs) are effective treatments for non-small cell lung cancers (NSCLCs) with epidermal growth factor receptor (EGFR) mutations. However, they do not lead to cures, and, on average, relapse occurs after one year of continuous treatment. In a subset of patients, a fundamental histological transformation from NSCLC to small cell lung cancer (SCLC) is observed in the resistant cancers, but the molecular changes associated with this transformation remain unknown. Analysis of a cohort of tumor samples and cell lines derived from resistant EGFR mutant patients with SCLC transformation revealed that RB is lost in 100% of these cases, but rarely in those that remain NSCLC. Global changes in gene expression, including increased neuroendocrine marker expression and absence of EGFR expression, are observed in cancers that transformed to SCLC. Consistent with their genetic and epigenetic similarities to classical SCLC, cell lines derived from resistant EGFR mutant SCLC biopsies are substantially more sensitive to ABT-263 treatment compared to those derived from resistant EGFR mutant NSCLCs. Together, these findings suggest that despite developing initially as EGFR mutant adenocarcinomas, this subset of resistant cancers ultimately take on many of the molecular and phenotypic characteristics of classical SCLC.
Project description:The study was designed to identify the molecular changes that occur in EGFR mutant NSCLCs that become resistant to TKI by transforming to SCLC. Tyrosine kinase inhibitors (TKIs) are effective treatments for non-small cell lung cancers (NSCLCs) with epidermal growth factor receptor (EGFR) mutations. However, they do not lead to cures, and, on average, relapse occurs after one year of continuous treatment. In a subset of patients, a fundamental histological transformation from NSCLC to small cell lung cancer (SCLC) is observed in the resistant cancers, but the molecular changes associated with this transformation remain unknown. Analysis of a cohort of tumor samples and cell lines derived from resistant EGFR mutant patients with SCLC transformation revealed that RB is lost in 100% of these cases, but rarely in those that remain NSCLC. Global changes in gene expression, including increased neuroendocrine marker expression and absence of EGFR expression, are observed in cancers that transformed to SCLC. Consistent with their genetic and epigenetic similarities to classical SCLC, cell lines derived from resistant EGFR mutant SCLC biopsies are substantially more sensitive to ABT-263 treatment compared to those derived from resistant EGFR mutant NSCLCs. Together, these findings suggest that despite developing initially as EGFR mutant adenocarcinomas, this subset of resistant cancers ultimately take on many of the molecular and phenotypic characteristics of classical SCLC.