1
|
Tsubaki M, Takeda T, Koumoto Y, Usami T, Matsuda T, Seki S, Sakai K, Nishio K, Nishida S. Activation of ERK1/2 by MOS and TPL2 leads to dasatinib resistance in chronic myeloid leukaemia cells. Cell Prolif 2023:e13420. [PMID: 36847709 DOI: 10.1111/cpr.13420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/21/2023] [Accepted: 01/27/2023] [Indexed: 03/01/2023] Open
Abstract
The development of BCR::ABL1 tyrosine kinase inhibitors (TKIs), such as dasatinib, has dramatically improved survival in cases of chronic myeloid leukaemia (CML). However, the development of resistance to BCR::ABL1 TKIs is a clinical problem. BCR::ABL1 TKI resistance is known to have BCR::ABL1-dependent or BCR::ABL1-independent mechanisms, but the mechanism of BCR::ABL1 independence is not well understood. In the present study, we investigated the mechanism of BCR::ABL1-independent dasatinib resistance. The expression and activation level of genes or proteins were evaluated using array CGH, real time PCR, or western blot analysis. Gene expression was modulated using siRNA-mediated knockdown. Cell survival was assessed by using trypan blue dye method. We found that dasatinib-resistant K562/DR and KU812/DR cells did not harbour a BCR::ABL1 mutation but had elevated expression and/or activation of MOS, TPL2 and ERK1/2. In addition, MOS siRNA, TPL2 siRNA and trametinib resensitized dasatinib-resistant cells to dasatinib. Moreover, expression levels of MOS in dasatinib non-responder patients with CML were higher than those in dasatinib responders, and the expression of TPL2 tended to increase in dasatinib non-responder patients compared with that in responder patients. Our results indicate that activation of ERK1/2 by elevated MOS and TPL2 expression is involved in dasatinib resistance, and inhibition of these proteins overcomes dasatinib resistance. Therefore, MOS, TPL2 and ERK1/2 inhibitors may be therapeutically useful for treating BCR::ABL1-independent dasatinib-resistant CML.
Collapse
Affiliation(s)
- Masanobu Tsubaki
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| | - Tomoya Takeda
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| | - Yuuichi Koumoto
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| | - Takehiro Usami
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| | - Takuya Matsuda
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| | - Shiori Seki
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| | - Kazuko Sakai
- Department of Genome Biology, Kindai University School of Medicine, Osakasayama, Osaka, Japan
| | - Kazuto Nishio
- Department of Genome Biology, Kindai University School of Medicine, Osakasayama, Osaka, Japan
| | - Shozo Nishida
- Division of Pharmacotherapy, Kindai University School of Pharmacy, Higashi-Osaka, Osaka, Japan
| |
Collapse
|
2
|
Zhou J, Chng WJ. Resistance to FLT3 inhibitors in acute myeloid leukemia: Molecular mechanisms and resensitizing strategies. World J Clin Oncol 2018; 9:90-97. [PMID: 30254964 PMCID: PMC6153124 DOI: 10.5306/wjco.v9.i5.90] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/02/2018] [Accepted: 08/07/2018] [Indexed: 02/06/2023] Open
Abstract
FMS-like tyrosine kinase 3 (FLT3) is classified as a type III receptor tyrosine kinase, which exerts a key role in regulation of normal hematopoiesis. FLT3 mutation is the most common genetic mutation in acute myeloid leukemia (AML) and represents an attractive therapeutic target. Targeted therapy with FLT3 inhibitors in AML shows modest promising results in current ongoing clinical trials suggesting the complexity of FLT3 targeting in therapeutics. Importantly, resistance to FLT3 inhibitors may explain the lack of overwhelming response and could obstruct the successful treatment for AML. Here, we summarize the molecular mechanisms of primary resistance and acquired resistance to FLT3 inhibitors and discuss the strategies to circumvent the emergency of drug resistance and to develop novel treatment intervention.
Collapse
Affiliation(s)
- Jianbiao Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore 117599, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074, Singapore
| | - Wee-Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore 117599, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074, Singapore
- Department of Hematology-Oncology, National University Cancer Institute, NUHS, Singapore 119228, Singapore
| |
Collapse
|
3
|
Zhou J, Toh SHM, Chan ZL, Quah JY, Chooi JY, Tan TZ, Chong PSY, Zeng Q, Chng WJ. A loss-of-function genetic screening reveals synergistic targeting of AKT/mTOR and WTN/β-catenin pathways for treatment of AML with high PRL-3 phosphatase. J Hematol Oncol 2018. [PMID: 29514683 PMCID: PMC5842526 DOI: 10.1186/s13045-018-0581-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Protein tyrosine phosphatase of regenerating liver 3 (PRL-3) is overexpressed in a subset of AML patients with inferior prognosis, representing an attractive therapeutic target. However, due to relatively shallow pocket of the catalytic site of PRL-3, it is difficult to develop selective small molecule inhibitor. Methods In this study, we performed whole-genome lentiviral shRNA library screening to discover synthetic lethal target to PRL-3 in AML. We used specific small molecule inhibitors to validate the synthetic lethality in human PRL-3 high vs PRL-3 low human AML cell lines and primary bone marrow cells from AML patients. AML mouse xenograft model was used to examine the in vivo synergism. Results The list of genes depleted in TF1-hPRL3 cells was particularly enriched for members involved in WNT/β-catenin pathway and AKT/mTOR signaling. These findings prompted us to explore the impact of AKT/mTOR signaling inhibition in PRL-3 high AML cells in combination with WNT/β-catenin inhibitor. VS-5584, a novel, highly selective dual PI3K/mTOR inhibitor, and ICG-001, a WNT inhibitor, were used as a combination therapy. A synthetic lethal interaction between mTOR/AKT pathway inhibition and WNT/β-catenin was validated by a variety of cellular assays. Notably, we found that treatment with these two drugs significantly reduced leukemic burden and prolonged survival of mice transplanted with human PRL-3 high AML cells, but not with PRL-3 low AML cells. Conclusions In summary, our results support the existence of cooperative signaling networks between AKT/mTOR and WNT/β-catenin pathways in PRL-3 high AML cells. Simultaneous inhibition of these two pathways could achieve robust clinical efficacy for this subtype of AML patient with high PRL-3 expression and warrant further clinical investigation. Electronic supplementary material The online version of this article (10.1186/s13045-018-0581-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jianbiao Zhou
- Cancer Science Institute of Singapore, Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | | | - Zit-Liang Chan
- Cancer Science Institute of Singapore, Singapore, Singapore
| | | | - Jing-Yuan Chooi
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, Singapore, Singapore.,Translational Centre for Development and Research, National University Health System, Singapore, Singapore
| | | | - Qi Zeng
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
| | - Wee-Joo Chng
- Cancer Science Institute of Singapore, Singapore, Singapore. .,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,Department of Hematology-Oncology, National University Cancer Institute of Singapore (NCIS), The National University Health System (NUHS), 1E, Kent Ridge Road, Singapore, 119228, Singapore.
| |
Collapse
|
4
|
Zhou J, Lu X, Tan TZ, Chng WJ. X-linked inhibitor of apoptosis inhibition sensitizes acute myeloid leukemia cell response to TRAIL and chemotherapy through potentiated induction of proapoptotic machinery. Mol Oncol 2017; 12:33-47. [PMID: 29063676 PMCID: PMC5748481 DOI: 10.1002/1878-0261.12146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/24/2017] [Accepted: 10/07/2017] [Indexed: 12/12/2022] Open
Abstract
Acute myeloid leukemia (AML) is an aggressive disease with an increasing incidence and relatively low 5‐year survival rate. Unfortunately, the underlying mechanism of leukemogenesis is poorly known, and there has been little progress in the treatment for AML. Studies have shown that X‐linked inhibitor of apoptosis (XIAP), one of the inhibitors of apoptosis proteins (IAPs), is highly expressed and contributes to chemoresistance in AML. Hence, a novel drug, RO6867520 (RO‐BIR2), developed by Roche targeting the BIR2 domain in XIAP to reactivate blocked apoptosis, is a promising therapy for AML. The monotherapy of RO‐BIR2 had minimal effect on most of the AML cell lines tested except U‐937. In contrast to AML cell lines, in general, RO‐BIR2 alone has been shown to inhibit the proliferation of primary AML patient samples effectively and induced apoptosis in a dose‐dependent manner. A combination of RO‐BIR2 with TNF‐related apoptosis‐inducing ligand (TRAIL) led to highly synergistic effect on AML cell lines and AML patient samples. This combination therapy is capable of inducing apoptosis, thereby leading to an increase in specific apoptotic cell population, along with the activation of caspase 3/7. A number of apoptotic‐related proteins such as XIAP, cleavage of caspase 3, cleavage of caspase 7, and cleaved PARP were changed upon combination therapy. Combination of RO‐BIR2 with Ara‐C had similar effect as the TRAIL combination. Ara‐C combination also led to synergistic effect on AML cell lines and AML patient samples with low combination indexes (CIs). We conclude that the combination of RO‐BIR2 with either TRAIL or Ara‐C represents a potent therapeutic strategy for AML and is warranted for further clinical trials to validate the synergistic benefits in patients with AML, especially for the elderly who are abstaining from intensive chemotherapy.
Collapse
Affiliation(s)
- Jianbiao Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Xiao Lu
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore.,Translational Centre for Development and Research, National University Health System, Singapore, Singapore
| | - Wee-Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Department of Hematology-Oncology, National University Cancer Institute, NUHS, Singapore, Singapore
| |
Collapse
|
5
|
Zhou J, Chng WJ. Aberrant RNA splicing and mutations in spliceosome complex in acute myeloid leukemia. Stem Cell Investig 2017; 4:6. [PMID: 28217708 DOI: 10.21037/sci.2017.01.06] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 12/29/2016] [Indexed: 12/19/2022]
Abstract
The spliceosome, the cellular splicing machinery, regulates RNA splicing of messenger RNA precursors (pre-mRNAs) into maturation of protein coding RNAs. Recurrent mutations and copy number changes in genes encoding spliceosomal proteins and splicing regulatory factors have tumor promoting or suppressive functions in hematological malignancies, as well as some other cancers. Leukemia stem cell (LSC) populations, although rare, are essential contributors of treatment failure and relapse. Recent researches have provided the compelling evidence that link the erratic spicing activity to the LSC phenotype in acute myeloid leukemia (AML). In this article, we describe the diverse roles of aberrant splicing in hematological malignancies, particularly in AML and their contributions to the characteristics of LSC. We review these promising strategies to exploit the addiction of aberrant spliceosomal machinery for anti-leukemic therapy with aim to eradicate LSC. However, given the complexity and plasticity of spliceosome and not fully known functions of splicing in cancer, the challenges facing the development of the therapeutic strategies targeting RAN splicing are highlighted and future directions are discussed too.
Collapse
Affiliation(s)
- Jianbiao Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore 117599, Singapore;; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Wee-Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore 117599, Singapore;; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore;; Department of Hematology-Oncology, National University Cancer Institute of Singapore (NCIS), The National University Health System (NUHS), Singapore 119228, Singapore
| |
Collapse
|
6
|
Zhou J, Chan ZL, Bi C, Lu X, Chong PSY, Chooi JY, Cheong LL, Liu SC, Ching YQ, Zhou Y, Osato M, Tan TZ, Ng CH, Ng SB, Wang S, Zeng Q, Chng WJ. LIN28B Activation by PRL-3 Promotes Leukemogenesis and a Stem Cell-like Transcriptional Program in AML. Mol Cancer Res 2016; 15:294-303. [PMID: 28011885 DOI: 10.1158/1541-7786.mcr-16-0275-t] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/29/2016] [Accepted: 11/18/2016] [Indexed: 12/17/2022]
Abstract
PRL-3 (PTP4A3), a metastasis-associated phosphatase, is also upregulated in patients with acute myeloid leukemia (AML) and is associated with poor prognosis, but the underlying molecular mechanism is unknown. Here, constitutive expression of PRL-3 in human AML cells sustains leukemogenesis in vitro and in vivo Furthermore, PRL-3 phosphatase activity dependently upregulates LIN28B, a stem cell reprogramming factor, which in turn represses the let-7 mRNA family, inducing a stem cell-like transcriptional program. Notably, elevated levels of LIN28B protein independently associate with worse survival in AML patients. Thus, these results establish a novel signaling axis involving PRL-3/LIN28B/let-7, which confers stem cell-like properties to leukemia cells that is important for leukemogenesis.Implications: The current study offers a rationale for targeting PRL-3 as a therapeutic approach for a subset of AML patients with poor prognosis. Mol Cancer Res; 15(3); 294-303. ©2016 AACR.
Collapse
Affiliation(s)
- Jianbiao Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Zit-Liang Chan
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Chonglei Bi
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Xiao Lu
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Phyllis S Y Chong
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Jing-Yuan Chooi
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Lip-Lee Cheong
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Shaw-Cheng Liu
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Ying Qing Ching
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Yafeng Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Motomi Osato
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore
| | - Chin Hin Ng
- Department of Haematology-Oncology, National University Cancer Institute, NUHS, Singapore, Republic of Singapore
| | - Siok-Bian Ng
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore.,Department of Pathology, National University Hospital, Singapore, Republic of Singapore.,Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shi Wang
- Department of Pathology, National University Hospital, National University Health System, Singapore
| | - Qi Zeng
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore, Republic of Singapore
| | - Wee-Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore, Republic of Singapore. .,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.,Department of Haematology-Oncology, National University Cancer Institute, NUHS, Singapore, Republic of Singapore
| |
Collapse
|
7
|
Chen J, Guo J, Chen Z, Wang J, Liu M, Pang X. Linifanib (ABT-869) Potentiates the Efficacy of Chemotherapeutic Agents through the Suppression of Receptor Tyrosine Kinase-Mediated AKT/mTOR Signaling Pathways in Gastric Cancer. Sci Rep 2016; 6:29382. [PMID: 27387652 PMCID: PMC4937412 DOI: 10.1038/srep29382] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/17/2016] [Indexed: 12/25/2022] Open
Abstract
Gastric cancer, highly dependent on tumor angiogenesis, causes uncontrolled lethality, in part due to chemoresistance. Here, we demonstrate that linifanib (ABT-869), a novel multi-targeted receptor tyrosine kinase inhibitor, markedly augments cytotoxicity of chemotherapies in human gastric cancer. ABT-869 and chemotherapeutic agents exhibited a strong synergy to inhibit the viability of several gastric cancer cell lines, with combination index values ranging from 0.017 to 0.589. Additionally, the combination of ABT-869 and chemotherapeutic agents led to remarkable suppression of vascular endothelial growth factor (VEGF)-induced angiogenesis in vitro and in vivo. Importantly, in a preclinical gastric cancer xenograft mouse model, drug co-treatments led to increased mouse survival as well as a synergistic reduction in tumor size and the inhibition of tumor angiogenesis. Mechanistic studies further revealed that all of the co-treatments containing ABT-869 resulted in decreased activation of the VEGF receptor, the epidermal growth factor receptor and the insulin growth factor receptor. Inhibition of these receptor tyrosine kinases consequently attenuated the activation of the downstream AKT/mTOR signaling pathway both in cultured gastric cancer cells and in gastric cancer xenografts. Collectively, our findings suggest that the addition of ABT-869 to traditional chemotherapies may be a promising strategy for the treatment of human gastric cancer.
Collapse
Affiliation(s)
- Jing Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China.,Key Laboratory of Reproduction and Genetics in Ningxia, Ningxia Medical University, Yinchuan 750004, China
| | - Jiawei Guo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhi Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jieqiong Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China.,Cancer Institute, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China.,Institute of Biosciences and Technology, Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Xiufeng Pang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| |
Collapse
|
8
|
Aversa C, Leone F, Zucchini G, Serini G, Geuna E, Milani A, Valdembri D, Martinello R, Montemurro F. Linifanib: current status and future potential in cancer therapy. Expert Rev Anticancer Ther 2015; 15:677-687. [DOI: 10.1586/14737140.2015.1042369] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
|
9
|
Autophagy inhibition sensitizes hepatocellular carcinoma to the multikinase inhibitor linifanib. Sci Rep 2014; 4:6683. [PMID: 25327881 PMCID: PMC4202209 DOI: 10.1038/srep06683] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 09/29/2014] [Indexed: 12/20/2022] Open
Abstract
Autophagy is a critical survival pathway for cancer cells under conditions of stress. Thus, induction of autophagy has emerged as a drug resistance mechanism. This study is to determine whether autophagy is activated by a novel multikinase inhibitor linifanib, thereby impairing the sensitivity of hepatocellular carcinoma (HCC) cells to this targeted therapy. Here, we found that linifanib induced a high level of autophagy in HCC cells, which was accompanied by suppression of phosphorylation of PDGFR-β and its downstream Akt/mTOR and Mek/Erk signaling pathways. Cell death induced by linifanib was greatly enhanced after autophagy inhibition by the pharmacological inhibitors or siRNAs against autophagy related genes, ATG5 and ATG7, in vitro. Moreover, HCQ, an FDA-approved drug used to inhibit autophagy, could significantly augment the anti-HCC effect of linifanib in a mouse xenograft model. In conclusion, linifanib can induce cytoprotective autophagy by suppression of PDGFR-β activities in HCC cells. Thus, autophagy inhibition represents a promising approach to improve the efficacy of linifanib in the treatment of HCC patients.
Collapse
|
10
|
Wang ES, Yee K, Koh LP, Hogge D, Enschede S, Carlson DM, Dudley M, Glaser K, McKeegan E, Albert DH, Li X, Pradhan R, Stock W. Phase 1 trial of linifanib (ABT-869) in patients with refractory or relapsed acute myeloid leukemia. Leuk Lymphoma 2012; 53:1543-51. [PMID: 22280537 DOI: 10.3109/10428194.2012.660631] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Linifanib, a potent oral inhibitor of fms-like tyrosine kinase 3 (FLT3) and vascular endothelial growth factor receptor tyrosine kinases, has demonstrated promising preclinical single-agent and synergistic anti-leukemic activity in combination with cytarabine. In this phase 1, multicenter, open-label, dose-escalation study, 45 adults with relapsed/refractory acute myeloid leukemia (AML) received linifanib alone in arm A (n = 29) and linifanib plus intermediate-dose cytarabine in arm B (n = 16). Median treatment duration was 21 days (range 5-110). Linifanib was well tolerated overall. The most common grade 3/4 events were fatigue (arm A) and febrile neutropenia (arm B). The recommended phase 2 dose was 15 mg (alone), and 10 mg (with cytarabine). Evidence of on-target kinase inhibition in patients with FLT3-mutant and wild-type AML was seen. Decreased phosphorylated FLT3 was seen in 3/3 patients with FLT3-internal tandem duplication (ITD) with peripheral blast reductions and in 8/24 (33%) patients with wild-type, D835 or unknown FLT3 mutation. Eight/29 (28%) patients had decreased phosphorylated extracellular signal-regulated kinase (ERK).
Collapse
Affiliation(s)
- Eunice S Wang
- Leukemia Service, Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Xie Z, Bi C, Cheong LL, Liu SC, Huang G, Zhou J, Yu Q, Chen CS, Chng WJ. Determinants of sensitivity to DZNep induced apoptosis in multiple myeloma cells. PLoS One 2011; 6:e21583. [PMID: 21720561 PMCID: PMC3123372 DOI: 10.1371/journal.pone.0021583] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 06/03/2011] [Indexed: 01/09/2023] Open
Abstract
The 3-Deazaneplanocin A (DZNep), one of S-adenosylhomocysteine (AdoHcy) hydrolase inhibitors, has shown antitumor activities in a broad range of solid tumors and acute myeloid leukemia. Here, we examined its effects on multiple myeloma (MM) cells and found that, at 500 nM, it potently inhibited growth and induced apoptosis in 2 of 8 MM cell lines. RNA from un-treated and DZNep treated cells was profiled by Affymetrix HG-U133 Plus 2.0 microarray and genes with a significant change in gene expression were determined by significance analysis of microarray (SAM) testing. ALOX5 was the most down-regulated gene (5.8-fold) in sensitive cells and was expressed at low level in resistant cells. The results were corroborated by quantitative RT-PCR. Western-blot analysis indicated ALOX5 was highly expressed only in sensitive cell line H929 and greatly decreased upon DZNep treatment. Ectopic expression of ALOX5 reduced sensitivity to DZNep in H929 cells. Furthermore, down-regulation of ALOX5 by RNA interference could also induce apoptosis in H929. Gene expression analysis on MM patient dataset indicated ALOX5 expression was significantly higher in MM patients compared to normal plasma cells. We also found that Bcl-2 was overexpressed in DZNep insensitive cells, and cotreatment with DZNep and ABT-737, a Bcl-2 family inhibitor, synergistically inhibited growth and induced apoptosis of DZNep insensitive MM cells. Taken together, this study shows one of mechanisms of the DZNep efficacy on MM correlates with its ability to down-regulate the ALOX5 levels. In addition, DZNep insensitivity might be associated with overexpression of Bcl-2, and the combination of ABT-737 and DZNep could synergistically induced apoptosis. These results suggest that DZNep may be exploited therapeutically for a subset of MM.
Collapse
Affiliation(s)
- Zhigang Xie
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
PRL-3, a metastasis associated tyrosine phosphatase, is involved in FLT3-ITD signaling and implicated in anti-AML therapy. PLoS One 2011; 6:e19798. [PMID: 21589872 PMCID: PMC3093398 DOI: 10.1371/journal.pone.0019798] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 04/13/2011] [Indexed: 02/06/2023] Open
Abstract
Combination with other small molecule drugs represents a promising strategy to improve therapeutic efficacy of FLT3 inhibitors in the clinic. We demonstrated that combining ABT-869, a FLT3 inhibitor, with SAHA, a HDAC inhibitor, led to synergistic killing of the AML cells with FLT3 mutations and suppression of colony formation. We identified a core gene signature that is uniquely induced by the combination treatment in 2 different leukemia cell lines. Among these, we showed that downregulation of PTP4A3 (PRL-3) played a role in this synergism. PRL-3 is downstream of FLT3 signaling and ectopic expression of PRL-3 conferred therapeutic resistance through upregulation of STAT (signal transducers and activators of transcription) pathway activity and anti-apoptotic Mcl-1 protein. PRL-3 interacts with HDAC4 and SAHA downregulates PRL-3 via a proteasome dependent pathway. In addition, PRL-3 protein was identified in 47% of AML cases, but was absent in myeloid cells in normal bone marrows. Our results suggest such combination therapies may significantly improve the therapeutic efficacy of FLT3 inhibitors. PRL-3 plays a potential pathological role in AML and it might be a useful therapeutic target in AML, and warrant clinical investigation.
Collapse
|
13
|
Hernandez-Davies JE, Zape JP, Landaw EM, Tan X, Presnell A, Griffith D, Heinrich MC, Glaser KB, Sakamoto KM. The multitargeted receptor tyrosine kinase inhibitor linifanib (ABT-869) induces apoptosis through an Akt and glycogen synthase kinase 3β-dependent pathway. Mol Cancer Ther 2011; 10:949-59. [PMID: 21471285 DOI: 10.1158/1535-7163.mct-10-0904] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The FMS-like receptor tyrosine kinase 3 (FLT3) plays an important role in controlling differentiation and proliferation of hematopoietic cells. Activating mutations in FLT3 occur in patients with acute myeloid leukemia (AML; 15%-35%), resulting in abnormal cell proliferation. Furthermore, both adult and pediatric patients with AML harboring the FLT3 internal tandem duplication (ITD) mutation have a poor prognosis. Several inhibitors have been developed to target mutant FLT3 for the treatment of AML, yet the molecular pathways affected by drug inhibition of the mutated FLT3 receptor alone have not been characterized as yet. Linifanib (ABT-869) is a multitargeted tyrosine kinase receptor inhibitor that suppresses FLT3 signaling. In this article, we show that treatment with linifanib inhibits proliferation and induces apoptosis in ITD mutant cells in vitro and in vivo. We show that treatment with linifanib reduces phosphorylation of Akt and glycogen synthase kinase 3β (GSK3β). In addition, we show that inhibition of GSK3β decreases linifanib-induced apoptosis. This study shows the importance of GSK3 as a potential target for AML therapy, particularly in patients with FLT3 ITD mutations.
Collapse
Affiliation(s)
- Jenny E Hernandez-Davies
- Division of Hematology-Oncology, Gwynne Hazen Cherry Memorial Laboratories, Mattel Children's Hospital UCLA, Jonsson Comprehensive Cancer Center, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Lee J, Paek SM, Han SY. FMS-like tyrosine kinase 3 inhibitors: a patent review. Expert Opin Ther Pat 2011; 21:483-503. [DOI: 10.1517/13543776.2011.560115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
15
|
L-carnitine reduces doxorubicin-induced apoptosis through a prostacyclin-mediated pathway in neonatal rat cardiomyocytes. Int J Cardiol 2011; 146:145-52. [DOI: 10.1016/j.ijcard.2009.06.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 05/12/2009] [Accepted: 06/06/2009] [Indexed: 11/18/2022]
|
16
|
Raja AM, Xu S, Sun W, Zhou J, Tai DCS, Chen CS, Rajapakse JC, So PTC, Yu H. Pulse-modulated second harmonic imaging microscope quantitatively demonstrates marked increase of collagen in tumor after chemotherapy. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:056016. [PMID: 21054110 DOI: 10.1117/1.3497565] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pulse-modulated second harmonic imaging microscopes (PM-SHIMs) exhibit improved signal-to-noise ratio (SNR) over conventional SHIMs on sensitive imaging and quantification of weak collagen signals inside tissues. We quantify the spatial distribution of sparse collagen inside a xenograft model of human acute myeloid leukemia (AML) tumor specimens treated with a new drug against receptor tyrosine kinase (ABT-869), and observe a significant increase in collagen area percentage, collagen fiber length, fiber width, and fiber number after chemotherapy. This finding reveals new insights into tumor responses to chemotherapy and suggests caution in developing new drugs and therapeutic regimens against cancers.
Collapse
MESH Headings
- Animals
- Antineoplastic Agents/therapeutic use
- Cell Line, Tumor
- Collagen/metabolism
- Female
- Humans
- Image Interpretation, Computer-Assisted
- Indazoles/therapeutic use
- Lasers
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Mice
- Mice, SCID
- Microscopy/instrumentation
- Microscopy/methods
- Neoplasms/drug therapy
- Neoplasms/metabolism
- Neoplasms/pathology
- Optical Phenomena
- Phenylurea Compounds/therapeutic use
- Receptor Protein-Tyrosine Kinases/antagonists & inhibitors
- Transplantation, Heterologous
Collapse
Affiliation(s)
- Anju M Raja
- A*STAR, Institute of Bioengineering and Nanotechnology, Singapore 138669
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Zhou J, Goh BC, Albert DH, Chen CS. ABT-869, a promising multi-targeted tyrosine kinase inhibitor: from bench to bedside. J Hematol Oncol 2009; 2:33. [PMID: 19642998 PMCID: PMC2729745 DOI: 10.1186/1756-8722-2-33] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 07/30/2009] [Indexed: 12/12/2022] Open
Abstract
Tyrosine Kinase Inhibitors (TKI) have significantly changed the landscape of current cancer therapy. Understanding of mechanisms of aberrant TK signaling and strategies to inhibit TKs in cancer, further promote the development of novel agents.ABT-869, a novel ATP-competitive receptor tyrosine kinase inhibitor is a potent inhibitor of members of the vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) receptor families. ABT-869 showed potent antiproliferative and apoptotic properties in vitro and in animal cancer xenograft models using tumor cell lines that were "addicted" to signaling of kinases targeted by ABT-869. When given together with chemotherapy or mTOR inhibitors, ABT-869 showed at least additive therapeutic effects. The phase I trial for ABT-869 was recently completed and it demonstrated respectable efficacy in solid tumors including lung and hepatocellular carcinoma with manageable side effects. Tumor cavitation and reduction of contrast enhancement after ABT-869 treatment supported the antiangiogenic activity. The correlative laboratory studies conducted with the trial also highlight potential biomarkers for future patient selection and treatment outcome.Parallel to the clinical development, in vitro studies on ABT-869 resistance phenotype identified novel resistance mechanism that may be applicable to other TKIs. The future therapeutic roles of ABT-869 are currently been tested in phase II trials.
Collapse
Affiliation(s)
- Jianbiao Zhou
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Boon-Cher Goh
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
- Department of Hematology and Oncology, National University Hospital, Singapore
| | - Daniel H Albert
- Cancer Research, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Chien-Shing Chen
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- School of Medicine, Division of Hematology and Oncology, Loma Linda University, Loma Linda, California, USA
| |
Collapse
|
18
|
Weisberg E, Barrett R, Liu Q, Stone R, Gray N, Griffin JD. FLT3 inhibition and mechanisms of drug resistance in mutant FLT3-positive AML. Drug Resist Updat 2009; 12:81-9. [PMID: 19467916 DOI: 10.1016/j.drup.2009.04.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 04/16/2009] [Accepted: 04/16/2009] [Indexed: 10/20/2022]
Abstract
An appealing therapeutic target in AML is constitutively activated, mutant FLT3, which is expressed in a subpopulation of AML patients and is generally a poor prognostic indicator in patients under the age of 65. There are currently several FLT3 inhibitors that are undergoing clinical investigation. However, the discovery of drug-resistant leukemic blast cells in FLT3 inhibitor-treated AML patients has prompted the search for novel, structurally diverse FLT3 inhibitors that could be alternatively used to circumvent drug resistance. Here, we provide an overview of FLT3 inhibitors under preclinical and clinical investigation, and we discuss mechanisms whereby AML cells develop resistance to FLT3 inhibitors, and the ways in which combination therapy could potentially be utilized to override drug resistance. We discuss how the cross-talk between major downstream signaling pathways, such as PI3K/PTEN/Akt/mTOR, RAS/Raf/MEK/ERK, and Jak/STAT, can be exploited for therapeutic purposes by targeting key signaling molecules with selective inhibitors, such as mTOR inhibitors, HSP90 inhibitors, or farnesyltransferase inhibitors, and identifying those agents with the ability to positively combine with inhibitors of FLT3, such as PKC412 and sunitinib. With the widespread onset of drug resistance associated with tyrosine kinase inhibitors, due to mechanisms involving development of point mutations or gene amplification of target proteins, the use of a multi-targeted therapeutic approach is of potential clinical benefit.
Collapse
Affiliation(s)
- Ellen Weisberg
- Department of Medical Oncology/Hematologic Neoplasia, Dana Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Franklin PH, Banfor PN, Tapang P, Segreti JA, Widomski DL, Larson KJ, Noonan WT, Gintant GA, Davidsen SK, Albert DH, Fryer RM, Cox BF. Effect of the Multitargeted Receptor Tyrosine Kinase Inhibitor, ABT-869 [N-(4-(3-Amino-1H-indazol-4-yl)phenyl)-N′-(2-fluoro-5-methylphenyl)urea], on Blood Pressure in Conscious Rats and Mice: Reversal with Antihypertensive Agents and Effect on Tumor Growth Inhibition. J Pharmacol Exp Ther 2009; 329:928-37. [DOI: 10.1124/jpet.108.144816] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
20
|
Mechanisms of resistance to FLT3 inhibitors. Drug Resist Updat 2009; 12:8-16. [PMID: 19162530 DOI: 10.1016/j.drup.2008.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 12/02/2008] [Indexed: 11/21/2022]
Abstract
The success of the small molecule tyrosine kinase receptor inhibitor (TKI) imatinib mesylate (Gleevec) in the treatment of chronic myeloid leukemia (CML) constitutes an eminent paradigm shift advocating the rational design of cancer therapeutics specifically targeting the transformation events that drive tumorigenicity. In acute myeloid leukemias (AMLs), the most frequent identified transforming events are activating mutations in the FLT3 receptor tyrosine kinase that constitutively activate survival and proliferation pathways. FLT3 TKIs that are in various phases of clinical trials are showing some initial promise. However, primary and secondary acquired resistance stands to severely compromise long-term and durable efficacy of these inhibitors as a therapeutic strategy. Here, we discuss the mechanisms of resistance to FLT3 inhibitors and possible strategies to overcome resistance through closer examination of the events of leukemogenesis and design of combination therapy.
Collapse
|
21
|
Enhanced activation of STAT pathways and overexpression of survivin confer resistance to FLT3 inhibitors and could be therapeutic targets in AML. Blood 2009; 113:4052-62. [PMID: 19144991 DOI: 10.1182/blood-2008-05-156422] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To further investigate potential mechanisms of resistance to FLT3 inhibitors, we developed a resistant cell line by long-term culture of MV4-11 cells with ABT-869, designated as MV4-11-R. Gene profiling reveals up-regulation of FLT3LG (FLT3 ligand) and BIRC5 (survivin), but down-regulation of SOCS1, SOCS2, and SOCS3 in MV4-11-R cells. Hypermethylation of these SOCS genes leads to their transcriptional silencing. Survivin is directly regulated by STAT3. Stimulation of the parental MV4-11 cells with FLT3 ligand increases the expression of survivin and phosphorylated protein STAT1, STAT3, STAT5. Targeting survivin by short-hairpin RNA (shRNA) in MV4-11-R cells induces apoptosis and augments ABT-869-mediated cytotoxicity. Overexpression of survivin protects MV4-11 from apoptosis. Subtoxic dose of indirubin derivative (IDR) E804 resensitizes MV4-11-R to ABT-869 treatment by inhibiting STAT signaling activity and abolishing survivin expression. Combining IDR E804 with ABT-869 shows potent in vivo efficacy in the MV4-11-R xenograft model. Taken together, these results demonstrate that enhanced activation of STAT pathways and overexpression of survivin are important mechanisms of resistance to ABT-869, suggesting that the STAT pathways and survivin could be potential targets for reducing resistance developed in patients receiving FLT3 inhibitors.
Collapse
|
22
|
Jasinghe VJ, Xie Z, Zhou J, Khng J, Poon LF, Senthilnathan P, Glaser KB, Albert DH, Davidsen SK, Chen CS. ABT-869, a multi-targeted tyrosine kinase inhibitor, in combination with rapamycin is effective for subcutaneous hepatocellular carcinoma xenograft. J Hepatol 2008; 49:985-97. [PMID: 18930332 DOI: 10.1016/j.jhep.2008.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 07/25/2008] [Accepted: 08/18/2008] [Indexed: 01/13/2023]
Abstract
BACKGROUND/AIMS Receptor tyrosine kinase inhibitors (RTKIs) and mTOR inhibitors are potential novel anticancer therapies for HCC. We hypothesized that combination targeted on distinctive signal pathways would provide synergistic therapeutics. METHODS ABT-869, a novel RTKI, and rapamycin were investigated in HCC pre-clinical models. RESULTS Rapamycin, but not ABT-869, inhibited in vitro growth of Huh7 and SK-HEP-1 HCC cells in a dose dependant manner. However, in subcutaneous Huh7 and SK-HEP-1 xenograft models, either ABT-869 or rapamycin can significantly reduce tumor burden. Combination treatment reduced the tumors to the lowest volume (95+/-20mm(3)), and was significantly better than single agent treatment (p<0.05). Immunohistochemical staining of tumor shows that ABT-869 potently inhibits VEGF in HCC in vivo. In addition, the MAPK signaling pathway has been inhibited by significant inhibition of phosphorylation of p44/42 MAP kinase by ABT-869 in vivo. Rapamycin inhibits phosphorylation of p70 S6 kinase and 4E-BP-1, downstream targets of mTOR, and decreases VEGF. Combination treatment showed synergistic effect on expression levels of p27 in vivo. Dramatic inhibition of neo-angiogenesis by ABT-869 was also demonstrated. CONCLUSIONS HCC could potentially be treated with the combination treatment of ABT-869 and rapamycin. Clinical trials on combination therapy are warranted.
Collapse
Affiliation(s)
- Viraj J Jasinghe
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 5 Lower Kent Ridge Road, Singapore 119074, Singapore
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Hirosawa M, Nakahara M, Otosaka R, Imoto A, Okazaki T, Takahashi S. The p38 pathway inhibitor SB202190 activates MEK/MAPK to stimulate the growth of leukemia cells. Leuk Res 2008; 33:693-9. [PMID: 18995898 DOI: 10.1016/j.leukres.2008.09.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 08/14/2008] [Accepted: 09/25/2008] [Indexed: 11/25/2022]
Abstract
In this study, the biological effects of signal transduction inhibitors on leukemia cells were examined. We found that the p38 inhibitor SB202190 enhanced the growth of THP-1 and MV4-11 cells. To determine the pathway affected by SB202190, we examined the 50% effective dose (ED(50)) values for THP-1 cell growth in combination with several inhibitors. In the presence of SB202190, the ED(50) values for the farnesyltransferase inhibitor FPT inhibitor II and MEK inhibitor U0126 were significantly decreased. Western blot analysis revealed that SB202190 increased the phosphorylation of C-Raf and extracellular regulated kinase (ERK), suggesting that Ras-Raf-MEK-mitogen-activated protein kinase (MAPK) pathway activation is involved in the leukemia cell growth induced by SB202190.
Collapse
Affiliation(s)
- Megumi Hirosawa
- Division of Molecular Hematology, Kitasato University Graduate School of Medical Sciences, Japan
| | | | | | | | | | | |
Collapse
|
24
|
Pratz K, Levis M. Incorporating FLT3 inhibitors into acute myeloid leukemia treatment regimens. Leuk Lymphoma 2008; 49:852-63. [PMID: 18452067 DOI: 10.1080/10428190801895352] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
FMS-Like-Tyrosine kinase-3 (FLT3) mutations are found in about 30% of cases of acute myeloid leukemia and confer an increased relapse rate and reduced overall survival. Targeting of this tyrosine kinase by direction inhibition is the focus of both preclinical and clinical research in AML. Several molecules in clinical development inhibit FLT3 with varying degrees of specificity. Preclinical models suggest that these compounds enhance the cytotoxicity of conventional chemotherapeutics against FLT3 mutant leukemia cells. The pharmacodynamic interactions between FLT3 inhibitors and chemotherapy appear to be sequence dependent. When the FLT3 inhibitor is used prior to chemotherapy, antagonism is displayed, while if FLT3 inhibition is instituted after to exposure to chemotherapy, synergistic cytotoxicity is seen. The combination of FLT3 inhibitors with chemotherapy is also complicated by potential pharmacokinetic obstacles, such as plasma protein binding and p-glycoprotein interactions. Ongoing and future studies are aimed at incorporating FLT3 inhibitors into conventional induction and consolidation therapy specifically for patients with FLT3 mutant AML.
Collapse
Affiliation(s)
- Keith Pratz
- Division of Hematologic Malignancies, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
| | | |
Collapse
|