Dataset Information

Combined inhibition of Notch and FLT3 produces synergistic cytotoxic effects in FLT3/ITD⁺ acute myeloid leukemia.

ABSTRACT: Internal tandem duplication (ITD) mutations of FMS-like tyrosine kinase-3 (FLT3) are the most frequent genetic alterations in acute myeloid leukemia (AML) and predict a poor prognosis. FLT3 tyrosine kinase inhibitors (TKIs) provide short-term clinical responses, but the long-term prognosis of FLT3/ITD⁺ AML patients remains poor. Notch signaling is important in numerous types of tumors. However, the role of Notch signaling in FLT3/ITD⁺ AML remains to be elucidated. In the current study, we found that Notch signaling was activated upon FLT3-TKI treatment in FLT3/ITD⁺ cell lines and primary cells. As Notch signaling can be blocked by γ-secretase inhibitors (GSIs), we examined the combinatorial antitumor efficacy of FLT3-TKIs and GSIs against FLT3/ITD⁺ AML and explored the underlying molecular mechanisms. As a result, we observed synergistic cytotoxic effects, and the treatment preferentially reduced cell proliferation and induced apoptosis in FLT3/ITD⁺ AML cell lines and in primary AML cells. Furthermore, the combination of FLT3-TKI and GSI eradicated leukemic cells and prolonged survival in an FLT3/ITD⁺ patient-derived xenograft AML model. Mechanistically, differential expression analysis suggested that CXCR3 may be partially responsible for the observed synergy, possibly through ERK signaling. Our findings suggest that combined therapies of FLT3-TKIs with GSI may be exploited as a potential therapeutic strategy to treat FLT3/ITD⁺ AML.

SUBMITTER: Li D

PROVIDER: S-EPMC7067872 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Combined inhibition of Notch and FLT3 produces synergistic cytotoxic effects in FLT3/ITD+ acute myeloid leukemia.

Li Dan D Li Tongjuan T Shang Zhen Z Zhao Lei L Xu Qian Q Tan Jiaqi J Qin Yun Y Zhang Yuanyuan Y Cao Yang Y Wang Na N Huang Liang L Zhu Xiaojian X Zhou Kuangguo K Chen Liting L Li Chunrui C Xie Ting T Yang Yi Y Wang Jue J Zhou Jianfeng J

Signal transduction and targeted therapy 20200313 1

Internal tandem duplication (ITD) mutations of FMS-like tyrosine kinase-3 (FLT3) are the most frequent genetic alterations in acute myeloid leukemia (AML) and predict a poor prognosis. FLT3 tyrosine kinase inhibitors (TKIs) provide short-term clinical responses, but the long-term prognosis of FLT3/ITD+ AML patients remains poor. Notch signaling is important in numerous types of tumors. However, the role of Notch signaling in FLT3/ITD+ AML remains to be elucidated. In the cu ...[more]

PMID: 32296014

Similar Datasets

Project description:AXL receptor tyrosine kinase (AXL) upregulation mediates drug resistance in several types of human cancer and has become a therapeutic target worthy of exploration. The present study investigated AXL antigen expression and the effects of novel AXL-targeted agents in acute myeloid leukemia (AML) cells. AXL antigen expression in drug-sensitive and drug-resistant human AML cell lines, and AML blast cells from 57 patients with different clinical characteristics, was analyzed by flow cytometry and compared. Furthermore, the effects of the novel AXL antibody DAXL-88, antibody-drug conjugate DAXL-88-monomethyl auristatin E (MMAE), AXL small molecule inhibitor R428 and their combination with FMS-like tyrosine kinase 3 (FLT3) inhibitor quizartinib (AC220) in AML cells were analyzed by Cell Counting Kit-8 assay, flow cytometry and western blotting. The present study revealed that AXL antigen expression was upregulated in FLT3-internal tandem duplication (ITD)/tyrosine kinase domain mutation-positive (TKD)+ AML blast cells compared with FLT3-ITD/TKD- AML cells. Additionally, AXL antigen expression was markedly upregulated in the AC220-resistant FLT3-ITD+ MV4-11 cell line (MV4-11/AC220) and in FLT3 inhibitor-resistant blast cells from a patient with FLT3-ITD+ AML compared with parental sensitive cells. The AXL-targeted agents DAXL-88, DAXL-88-MMAE and R428 exhibited dose-dependent cytotoxic effects on FLT3-mutant AML cell lines (THP-1, MV4-11 and MV4-11/AC220) and blast cells from patients with FLT3-ITD+ AML. Combinations of AXL-targeted agents with AC220 exerted synergistic cytotoxic effects and induced apoptosis in MV4-11/AC220 cells and FLT3 inhibitor-resistant blast cells. The antileukemic effect of DAXL-88 and DAXL-88-MMAE may rely on their ability to block AXL, FLT3 and their downstream signaling pathways. The present study demonstrated the association between AXL antigen expression upregulation and drug resistance in FLT3-ITD+ AML, and proposed a method for overcoming FLT3 inhibitor resistance of FLT3-ITD+ AML using novel AXL-targeted agents.

Project description:Acute myeloid leukemia (AML) is an aggressive hematologic malignancy which is cured in a minority of patients. A FLT3-internal tandem duplication (ITD) mutation, found in approximately a quarter of patients with de novo AML, imparts a particularly poor prognosis. Patients with FLT3-ITD AML often present with more aggressive disease and have a significantly higher propensity for relapse after remission. The therapeutic approach for these patients has traditionally included intensive induction chemotherapy, followed by consolidative chemotherapy or hematopoietic cell transplantation (HCT). In recent years, multiple small molecule inhibitors of the FLT3 tyrosine kinase have been studied preclinically and in clinical trials. The earlier generation of these agents, often non-specific and impacting a variety of tyrosine kinases, produced at best transient peripheral blood responses in early clinical trials. Additionally, the combination of FLT3 inhibitors with cytotoxic regimens has not, as of yet, demonstrated an improvement in overall survival. Nevertheless, multiple current trials, including those with sorafenib, lestaurtinib, and midostaurin, continue to study the combination of FLT3 inhibitors with standard chemotherapy. Factors such as sustained FLT3 inhibition, protein binding, pharmacokinetics, and the presence of elevated FLT3-ligand levels appear to significantly impact the potency of these agents in vivo. In recent years, the development of more specific and potent agents has generated hope that FLT3 inhibitors may play a more prominent role in the treatment of FLT3-ITD AML in the near future. Nevertheless, questions remain regarding the optimal timing and schedule for incorporation of FLT3 inhibitors. The suitability, type, and timing of allogeneic HCT in the therapeutic approach for these patients are also issues which require further study and definition. Recent retrospective data appears to support the efficacy of allogeneic HCT in first complete remission, possibly due to a graft versus leukemia effect. However, larger prospective studies are necessary to further elucidate the role of HCT and its potential combination with FLT3 inhibitor therapy. We are hopeful that current clinical investigation will lead to an optimization and improvement of outcomes for these patients.

Project description:BackgroundApproximately 25-30% of patients with acute myeloid leukemia (AML) have FMS-like receptor tyrosine kinase-3 (FLT3) mutations that contribute to disease progression and poor prognosis. Prolonged exposure to FLT3 tyrosine kinase inhibitors (TKIs) often results in limited clinical responses due to diverse compensatory survival signals. Therefore, there is an urgent need to elucidate the mechanisms underlying FLT3 TKI resistance. Dysregulated sphingolipid metabolism frequently contributes to cancer progression and a poor therapeutic response. However, its relationship with TKI sensitivity in FLT3-mutated AML remains unknown. Thus, we aimed to assess mechanisms of FLT3 TKI resistance in AML.MethodsWe performed lipidomics profiling, RNA-seq, qRT-PCR, and enzyme-linked immunosorbent assays to determine potential drivers of sorafenib resistance. FLT3 signaling was inhibited by sorafenib or quizartinib, and SPHK1 was inhibited by using an antagonist or via knockdown. Cell growth and apoptosis were assessed in FLT3-mutated and wild-type AML cell lines via Cell counting kit-8, PI staining, and Annexin-V/7AAD assays. Western blotting and immunofluorescence assays were employed to explore the underlying molecular mechanisms through rescue experiments using SPHK1 overexpression and exogenous S1P, as well as inhibitors of S1P2, β-catenin, PP2A, and GSK3β. Xenograft murine model, patient samples, and publicly available data were analyzed to corroborate our in vitro results.ResultsWe demonstrate that long-term sorafenib treatment upregulates SPHK1/sphingosine-1-phosphate (S1P) signaling, which in turn positively modulates β-catenin signaling to counteract TKI-mediated suppression of FLT3-mutated AML cells via the S1P2 receptor. Genetic or pharmacological inhibition of SPHK1 potently enhanced the TKI-mediated inhibition of proliferation and apoptosis induction in FLT3-mutated AML cells in vitro. SPHK1 knockdown enhanced sorafenib efficacy and improved survival of AML-xenografted mice. Mechanistically, targeting the SPHK1/S1P/S1P2 signaling synergizes with FLT3 TKIs to inhibit β-catenin activity by activating the protein phosphatase 2 A (PP2A)-glycogen synthase kinase 3β (GSK3β) pathway.ConclusionsThese findings establish the sphingolipid metabolic enzyme SPHK1 as a regulator of TKI sensitivity and suggest that combining SPHK1 inhibition with TKIs could be an effective approach for treating FLT3-mutated AML.

Dataset Information

Combined inhibition of Notch and FLT3 produces synergistic cytotoxic effects in FLT3/ITD⁺ acute myeloid leukemia.

Publications

Combined inhibition of Notch and FLT3 produces synergistic cytotoxic effects in FLT3/ITD<sup>+</sup> acute myeloid leukemia.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets