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Li T, Zheng J, Huang T, Wang X, Li J, Jin F, Wei W, Chen X, Liu C, Bao M, Zhao G, Huang L, Zhao D, Chen J, Bu Z, Weng C. Identification of several African swine fever virus replication inhibitors by screening of a library of FDA-approved drugs. Virology 2024; 593:110014. [PMID: 38401340 DOI: 10.1016/j.virol.2024.110014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/03/2024] [Accepted: 02/06/2024] [Indexed: 02/26/2024]
Abstract
African swine fever (ASF) caused by African swine fever virus (ASFV) is a highly infectious and lethal swine disease. Currently, there is only one novel approved vaccine and no antiviral drugs for ASFV. In the study, a high-throughput screening of an FDA-approved drug library was performed to identify several drugs against ASFV infection in primary porcine alveolar macrophages. Triapine and cytarabine hydrochloride were identified as ASFV infection inhibitors in a dose-dependent manner. The two drugs executed their antiviral activity during the replication stage of ASFV. Furthermore, molecular docking studies showed that triapine might interact with the active center Fe2+ in the small subunit of ASFV ribonucleotide reductase while cytarabine hydrochloride metabolite might interact with three residues (Arg589, Lys593, and Lys631) of ASFV DNA polymerase to block new DNA chain extension. Taken together, our results suggest that triapine and cytarabine hydrochloride displayed significant antiviral activity against ASFV in vitro.
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Affiliation(s)
- Tingting Li
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, 150069, China
| | - Jun Zheng
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China; Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, 150069, China
| | - Tao Huang
- Shenzhen Zhiyao Information Technology Co. Ltd., C1119, Innovation Plaza, Shenzhen, 518118, China
| | - Xiao Wang
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China
| | - Jiangnan Li
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China; Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, 150069, China
| | - Feng Jin
- Shenzhen Zhiyao Information Technology Co. Ltd., C1119, Innovation Plaza, Shenzhen, 518118, China
| | - Wenjuan Wei
- Shenzhen Zhiyao Information Technology Co. Ltd., C1119, Innovation Plaza, Shenzhen, 518118, China
| | - Xin Chen
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China
| | - Chuanxia Liu
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China
| | - Miaofei Bao
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China
| | - Gaihong Zhao
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China
| | - Li Huang
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China; Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, 150069, China
| | - Dongming Zhao
- National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China
| | - Jianxin Chen
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Zhigao Bu
- National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China.
| | - Changjiang Weng
- Division of Fundamental Immunology, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, 150069, China; National African Swine Fever Para-Reference Laboratory, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Harbin, 150069, China; Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, 150069, China.
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Corrales-Guerrero S, Cui T, Castro-Aceituno V, Yang L, Nair S, Feng H, Venere M, Yoon S, DeWees T, Shen C, Williams TM. Inhibition of RRM2 radiosensitizes glioblastoma and uncovers synthetic lethality in combination with targeting CHK1. Cancer Lett 2023; 570:216308. [PMID: 37482342 DOI: 10.1016/j.canlet.2023.216308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/29/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023]
Abstract
Glioblastoma (GBM) is an aggressive malignant primary brain tumor. Radioresistance largely contributes to poor clinical outcomes in GBM patients. We targeted ribonucleotide reductase subunit 2 (RRM2) with triapine to radiosensitize GBM. We found RRM2 is associated with increasing tumor grade, is overexpressed in GBM over lower grade gliomas and normal tissue, and is associated with worse survival. We found silencing or inhibition of RRM2 by siRNA or triapine sensitized GBM cells to ionizing radiation (IR) and delayed resolution of IR-induced γ-H2AX nuclear foci. In vivo, triapine and IR reduced tumor growth and increased mouse survival. Intriguingly, triapine led to RRM2 upregulation and CHK1 activation, suggesting a CHK1-dependent RRM2 upregulation following RRM2 inhibition. Consistently, silencing or inhibition of CHK1 with rabusertib abolished the triapine-induced RRM2 upregulation. Accordingly, combining rabusertib and triapine resulted in synthetic lethality in GBM cells. Collectively, our results suggest RRM2 is a promising therapeutic target for GBM, and targeting RRM2 with triapine sensitizes GBM cells to radiation and independently induces synthetic lethality of GBM cells with CHK1 inhibition. Our findings suggest combining triapine with radiation or rabusertib may improve therapeutic outcomes in GBM.
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Affiliation(s)
- Sergio Corrales-Guerrero
- Biomedical Sciences Graduate Program, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Tiantian Cui
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
| | | | - Linlin Yang
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
| | - Sindhu Nair
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
| | - Haihua Feng
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
| | - Monica Venere
- Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Arthur G. James Comprehensive Cancer Center and Richard J. Solove Research Institute, Columbus, OH, USA
| | - Stephanie Yoon
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
| | - Todd DeWees
- Division of Biostatistics, City of Hope, Duarte, CA, USA
| | - Changxian Shen
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
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3
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Sturm MJ, Henao-Restrepo JA, Becker S, Proquitté H, Beck JF, Sonnemann J. Synergistic anticancer activity of combined ATR and ribonucleotide reductase inhibition in Ewing's sarcoma cells. J Cancer Res Clin Oncol 2023:10.1007/s00432-023-04804-0. [PMID: 37097390 PMCID: PMC10374484 DOI: 10.1007/s00432-023-04804-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 04/19/2023] [Indexed: 04/26/2023]
Abstract
PURPOSE Ewing's sarcoma is a highly malignant childhood tumour whose outcome has hardly changed over the past two decades despite numerous attempts at chemotherapy intensification. It is therefore essential to identify new treatment options. The present study was conducted to explore the effectiveness of combined inhibition of two promising targets, ATR and ribonucleotide reductase (RNR), in Ewing's sarcoma cells. METHODS Effects of the ATR inhibitor VE821 in combination with the RNR inhibitors triapine and didox were assessed in three Ewing's sarcoma cell lines with different TP53 status (WE-68, SK-ES-1, A673) by flow cytometric analysis of cell death, mitochondrial depolarisation and cell cycle distribution as well as by caspase 3/7 activity determination, by immunoblotting and by real-time RT-PCR. Interactions between inhibitors were evaluated by combination index analysis. RESULTS Single ATR or RNR inhibitor treatment produced small to moderate effects, while their combined treatment produced strong synergistic ones. ATR and RNR inhibitors elicited synergistic cell death and cooperated in inducing mitochondrial depolarisation, caspase 3/7 activity and DNA fragmentation, evidencing an apoptotic form of cell death. All effects were independent of functional p53. In addition, VE821 in combination with triapine increased p53 level and induced p53 target gene expression (CDKN1A, BBC3) in p53 wild-type Ewing's sarcoma cells. CONCLUSION Our study reveals that combined targeting of ATR and RNR was effective against Ewing's sarcoma in vitro and thus rationalises an in vivo exploration into the potential of combining ATR and RNR inhibitors as a new strategy for the treatment of this challenging disease.
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Affiliation(s)
- Max-Johann Sturm
- Department of Paediatric and Adolescent Medicine, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, 07747, Jena, Germany
- Research Centre Lobeda, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Julián Andrés Henao-Restrepo
- Placenta Laboratory, Department of Obstetrics, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Sabine Becker
- Department of Paediatric and Adolescent Medicine, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, 07747, Jena, Germany
- Research Centre Lobeda, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Hans Proquitté
- Department of Paediatric and Adolescent Medicine, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, 07747, Jena, Germany
| | - James F Beck
- Department of Paediatric and Adolescent Medicine, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, 07747, Jena, Germany
| | - Jürgen Sonnemann
- Department of Paediatric and Adolescent Medicine, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, 07747, Jena, Germany.
- Research Centre Lobeda, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
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4
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Zhao Y, Zheng Y, Zhu Y, Ding K, Zhou M, Liu T. Co-delivery of gemcitabine and Triapine by calcium carbonate nanoparticles against chemoresistant pancreatic cancer. Int J Pharm 2023; 636:122844. [PMID: 36925025 DOI: 10.1016/j.ijpharm.2023.122844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 02/14/2023] [Accepted: 03/11/2023] [Indexed: 03/16/2023]
Abstract
Pancreatic cancer is a malignant disease with high mortality, and its systemic treatment strategy mainly focuses on chemotherapy. Yet, the overall prognosis of pancreatic cancer patients is still extremely poor with a low survival rate. Gemcitabine (GEM) is a widely used chemotherapeutic agent for the treatment of pancreatic cancer. However, GEM chemoresistance remains the major challenge. In this study, we prepared calcium carbonate nanoparticles (CaCO3 NPs) loaded with a nucleotide reductase inhibitor (Triapine) and GEM to suppress the GEM resistance of pancreatic cancer cells (PANC-1/GEM) and solve the problem of poor solubility of Triapine. CaCO3-GEM-Triapine NPs nano-formulations enhanced the therapeutic effect of GEM-based chemotherapy by inhibiting cancer cell proliferation, migration, and resistance to GEM using both 2D PANC-1/GEM cells and 3D tumor spheroids. The study indicated that CaCO3 NPs loaded with GEM and Triapine could provide an effective treatment option to overcome drug resistance in pancreatic cancer.
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Affiliation(s)
- Yongmei Zhao
- School of Pharmacy, Nantong University, Nantong, China
| | - Yuanlin Zheng
- School of Pharmacy, Nantong University, Nantong, China
| | - Yan Zhu
- School of Pharmacy, Nantong University, Nantong, China
| | - Kai Ding
- School of Pharmacy, Nantong University, Nantong, China
| | - Mengjiao Zhou
- School of Pharmacy, Nantong University, Nantong, China.
| | - Tianqing Liu
- NICM Health Research Institute, Western Sydney University, Westmead, Australia.
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5
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Ohmura S, Marchetto A, Orth MF, Li J, Jabar S, Ranft A, Vinca E, Ceranski K, Carreño-Gonzalez MJ, Romero-Pérez L, Wehweck FS, Musa J, Bestvater F, Knott MML, Hölting TLB, Hartmann W, Dirksen U, Kirchner T, Cidre-Aranaz F, Grünewald TGP. Translational evidence for RRM2 as a prognostic biomarker and therapeutic target in Ewing sarcoma. Mol Cancer 2021; 20:97. [PMID: 34315482 PMCID: PMC8314608 DOI: 10.1186/s12943-021-01393-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022] Open
Affiliation(s)
- Shunya Ohmura
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany.,Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Aruna Marchetto
- Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Martin F Orth
- Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Jing Li
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany
| | - Susanne Jabar
- Pediatrics III, West German Cancer Centre, University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), partner site Essen, Essen, Germany
| | - Andreas Ranft
- Pediatrics III, West German Cancer Centre, University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), partner site Essen, Essen, Germany
| | - Endrit Vinca
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany
| | - Katharina Ceranski
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany
| | - Martha J Carreño-Gonzalez
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany
| | - Laura Romero-Pérez
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany.,Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Fabienne S Wehweck
- Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Julian Musa
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany.,Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany.,Department of General, Visceral and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Felix Bestvater
- Light Microscopy Facility, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Maximilian M L Knott
- Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Tilman L B Hölting
- Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Wolfgang Hartmann
- Division of Translational Pathology, Gerhard-Domagk-Institute for Pathology, University Hospital Münster, Münster, Germany
| | - Uta Dirksen
- Pediatrics III, West German Cancer Centre, University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), partner site Essen, Essen, Germany
| | - Thomas Kirchner
- Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany.,German Cancer Consortium (DKTK), partner site Munich, Munich, Germany
| | - Florencia Cidre-Aranaz
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany.,Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Thomas G P Grünewald
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany. .,Division of Translational Pediatric Sarcoma Research (B410), German Cancer Research Center (DKFZ) & Hopp-Children's Cancer Center (KiTZ), Im Neuenheimer Feld 280, 69210, Heidelberg, Germany. .,Max-Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Munich, Germany. .,Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.
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Joshi A, Kiesel BF, Chaphekar N, Jones R, Guo J, Kunos CA, Taylor S, Chu E, Venkataramanan R, Beumer JH. In vitro evaluation of the metabolic enzymes and drug interaction potential of triapine. Cancer Chemother Pharmacol 2020; 86:633-40. [PMID: 32989483 DOI: 10.1007/s00280-020-04154-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 09/17/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate the metabolic pathways of triapine in primary cultures of human hepatocytes and human hepatic subcellular fractions; to investigate interactions of triapine with tenofovir and emtricitabine; and to evaluate triapine as a perpetrator of drug interactions. The results will better inform future clinical studies of triapine, a radiation sensitizer currently being studied in a phase III study. METHODS Triapine was incubated with human hepatocytes and subcellular fractions in the presence of a number of inhibitors of drug metabolizing enzymes. Triapine depletion was monitored by LC-MS/MS. Tenofovir and emtricitabine were co-incubated with triapine in primary cultures of human hepatocytes. Triapine was incubated with a CYP probe cocktail and human liver microsomes, followed by LC-MS/MS monitoring of CYP specific metabolite formation. RESULTS Triapine was not metabolized by FMO, AO/XO, MAO-A/B, or NAT-1/2, but was metabolized by CYP450s. CYP1A2 accounted for most of the depletion of triapine. Tenofovir and emtricitabine did not alter triapine depletion. Triapine reduced CYP1A2 activity and increased CYP2C19 activity. CONCLUSION CYP1A2 metabolism is the major metabolic pathway for triapine. Triapine may be evaluated in cancer patients in the setting of HIV with emtricitabine or tenofovir treatment. Confirmatory clinical trials may further define the in vivo triapine metabolic fate and quantify any drug-drug interactions.
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Abstract
Iron chelators have long been a target of interest as anticancer agents. Iron is an important cellular resource involved in cell replication, metabolism and growth. Iron metabolism is modulated in cancer cells reflecting their increased replicative demands. Originally, iron chelators were first developed for use in iron overload disorders, however, their potential as anticancer agents has been gaining increasing interest. This is due, in part, to the downstream effects of iron depletion such as the inhibition of proliferation through ribonucleotide reductase activity. Additionally, some chelators form redox active metal complexes with iron resulting in the production of reactive oxygen species and oxidative stress. Newer synthetic iron chelators such as Deferasirox, Triapine and di-2-pyridylketone-4,4,-dimethyl-3-thiosemicrbazone (Dp44mt) have improved pharmacokinetic properties over the older chelator Deferoxamine. This review examines and discusses the various iron chelators that have been trialled for cancer therapy including both preclinical and clinical studies. The successes and shortcomings of each of the chelators and their use in combination therapies are highlighted and future potential in the cancer therapy world is considered.
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Abstract
An electron paramagnetic resonance (EPR) method was used to determine the concentration of the antitumor agent Triapine in BEAS-2B cells when Triapine was bound to iron (Fe). Knowledge of the concentration of Fe-Triapine in tumor cells may be useful to adjust the administration of the drug or to adjust iron uptake in tumor cells. An EPR spectrum is obtained for Fe(3+)-Triapine, Fe(3+)(Tp)2+, in BEAS-2B cells after addition of Fe(3+)(Tp)2+. Detection of the low spin signal for Fe(3+)(Tp)2+ shows that the Fe(3+)(Tp)2+ complex is intact in these cells. It is proposed that Triapine acquires iron from transferrin in cells including tumor cells. Here, it is shown that iron from purified Fe-transferrin is transferred to Triapine after the addition of ascorbate. To our knowledge, this is the first time that the EPR method has been used to determine the concentration of an iron antitumor agent in cells.
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Affiliation(s)
- William E Antholine
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Charles R Myers
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Kallus S, Uhlik L, van Schoonhoven S, Pelivan K, Berger W, Enyedy ÉA, Hofmann T, Heffeter P, Kowol CR, Keppler BK. Synthesis and biological evaluation of biotin-conjugated anticancer thiosemicarbazones and their iron(III) and copper(II) complexes. J Inorg Biochem 2018; 190:85-97. [PMID: 30384010 DOI: 10.1016/j.jinorgbio.2018.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/01/2018] [Accepted: 10/14/2018] [Indexed: 12/24/2022]
Abstract
Triapine, the most prominent anticancer drug candidate from the substance class of thiosemicarbazones, was investigated in >30 clinical phase I and II studies. However, the results were rather disappointing against solid tumors, which can be explained (at least partially) due to inefficient delivery to the tumor site. Hence, we synthesized the first biotin-functionalized thiosemicarbazone derivatives in order to increase tumor specificity and accumulation. Additionally, for Triapine and one biotin conjugate the iron(III) and copper(II) complexes were prepared. Subsequently, the novel compounds were biologically evaluated on a cell line panel with different biotin uptake. The metal-free biotin-conjugated ligands showed comparable activity to the reference compound Triapine. However, astonishingly, the metal complexes of the biotinylated derivative showed strikingly decreased anticancer activity. To further analyze possible differences between the metal complexes, detailed physico- and electrochemical experiments were performed. However, neither lipophilicity or complex solution stability, nor the reduction potential or behavior in the presence of biologically relevant reducing agents showed strong variations between the biotinylated and non-biotinylated derivatives (only some differences in the reduction kinetics were observed). Nonetheless, the metal-free biotin-conjugate of Triapine revealed distinct activity in a colon cancer mouse model upon oral application comparable to Triapine. Therefore, this type of biotin-conjugated thiosemicarbazone is of interest for further synthetic strategies and biological studies.
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Affiliation(s)
- Sebastian Kallus
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria
| | - Lukas Uhlik
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkeg. 8a, A-1090 Vienna, Austria
| | - Sushilla van Schoonhoven
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkeg. 8a, A-1090 Vienna, Austria
| | - Karla Pelivan
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria
| | - Walter Berger
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkeg. 8a, A-1090 Vienna, Austria; Research Cluster "Translational Cancer Therapy Research", Vienna, Austria
| | - Éva A Enyedy
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720, Szeged, Hungary
| | - Thilo Hofmann
- Department of Environmental Geosciences, University of Vienna, Althanstraße 14, A-1090, Vienna, Austria
| | - Petra Heffeter
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkeg. 8a, A-1090 Vienna, Austria; Research Cluster "Translational Cancer Therapy Research", Vienna, Austria.
| | - Christian R Kowol
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria; Research Cluster "Translational Cancer Therapy Research", Vienna, Austria.
| | - Bernhard K Keppler
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria; Research Cluster "Translational Cancer Therapy Research", Vienna, Austria
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10
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Matsumoto J, Kiesel BF, Parise RA, Guo J, Taylor S, Huang M, Eiseman JL, Ivy SP, Kunos C, Chu E, Beumer JH. LC-MS/MS assay for the quantitation of the ribonucleotide reductase inhibitor triapine in human plasma. J Pharm Biomed Anal 2017; 146:154-160. [PMID: 28881312 DOI: 10.1016/j.jpba.2017.08.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/18/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
Abstract
The ribonucleotide reductase inhibitor and radiosensitizer triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP), NSC 663249) is clinically being evaluated via the intravenous (IV) route for the treatment of cervical and vulvar cancer in combination with primary cisplatin chemoradiation. The need for a 2-h infusion and frequent administration of triapine is logistically challenging, prompting us to pursue oral (PO) administration. In support of the clinical trial investigating oral triapine in combination with chemoradiation, we developed and validated a novel LC-MS/MS assay for the quantification of triapine in 50μL human plasma. After protein precipitation, chromatographic separation of the supernatant was achieved with a Shodex ODP2 column and an isocratic acetonitrile-water mobile phase with 10% ammonium acetate. Detection with an ABI 4000 mass spectrometer utilized electrospray positive mode ionization. The assay was linear from 3 to 3,000ng/mL and proved to be accurate (97.1-103.1%) and precise (<7.4% CV), and met the U.S. FDA guidance for bioanalytical method validation. This LC-MS/MS assay will be an essential tool to further define the pharmacokinetics and oral bioavailability of triapine.
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Affiliation(s)
- Julia Matsumoto
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States; School of Pharmaceutical Sciences, Sao Paulo State University, Araraquara, SP, Brazil
| | - Brian F Kiesel
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States; Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States
| | - Robert A Parise
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States
| | - Jianxia Guo
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States
| | - Sarah Taylor
- Division of Gynecologic Oncology, Department of Obstetrics, Gynecology, and Reproductive Medicine, University of Pittsburgh-Magee Women's Hospital, Pittsburgh, PA, United States
| | - Marilyn Huang
- Division of Gynecologic Oncology, Department of Obstetrics, Gynecology, and Reproductive Medicine, University of Pittsburgh-Magee Women's Hospital, Pittsburgh, PA, United States
| | - Julie L Eiseman
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States; Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - S Percy Ivy
- Investigational Drug Branch, Cancer Therapy Evaluation Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD, United States
| | - Charles Kunos
- Investigational Drug Branch, Cancer Therapy Evaluation Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD, United States
| | - Edward Chu
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States; Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jan H Beumer
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, United States; Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States.
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11
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Kunos CA, Chu E, Beumer JH, Sznol M, Ivy SP. Phase I trial of daily triapine in combination with cisplatin chemotherapy for advanced-stage malignancies. Cancer Chemother Pharmacol 2016; 79:201-207. [PMID: 27878356 DOI: 10.1007/s00280-016-3200-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/11/2016] [Indexed: 11/29/2022]
Abstract
PURPOSE Advanced-stage malignancies have increased deoxyribonucleotide demands in DNA replication and repair, making deoxyribonucleotide supply a potential exploitable target for therapy based on ribonucleotide reductase (RNR) inhibition. METHODS A dose-finding phase I trial was conducted of intravenous (i.v.) triapine, a small-molecule RNR inhibitor, and cisplatin chemotherapy in patients with advanced-stage solid tumor malignancies. Patients received dose-finding levels of i.v. triapine (48-96 mg/m2) and i.v. cisplatin (20-75 mg/m2) on 1 of 3 different schedules. The primary endpoint was to identify the maximum tolerated dose of a triapine-cisplatin combination. Secondary endpoints included the rate of triapine-cisplatin objective response and the pharmacokinetics and bioavailability of a single oral triapine dose. (Clinicaltrials.gov number, NCT00024323). RESULTS The MTD was 96 mg/m2 triapine daily days 1-4 and 75 mg/m2 cisplatin split over day 2 and day 3. Frequent grade 3 or 4 adverse events included fatigue, dyspnea, leukopenia, thrombocytopenia, and electrolyte abnormalities. No objective responses were observed; 5 (50%) of 10 patients treated at the MTD had stable disease. Pharmacokinetics indicated an oral triapine bioavailability of 88%. CONCLUSIONS The triapine-cisplatin combination may be given safely in patients with advanced-stage solid tumor malignancies. On the basis of these results, a phase I trial adequately powered to evaluate oral triapine bioavailability in women with advanced-stage uterine cervix or vulvar cancers is underway.
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Affiliation(s)
- Charles A Kunos
- Cancer Therapy Evaluation Program, National Cancer Institute, Bethesda, MD, USA.
- Investigational Drug Branch, Cancer Therapy Evaluation Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, MSC 9739, Rockville, MD, 20892-9760, USA.
| | - Edward Chu
- University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Jan H Beumer
- University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
- University of Pittsburgh School of Pharmacy, Pittsburgh, PA, USA
| | - Mario Sznol
- Yale University School of Medicine and Yale Cancer Center, New Haven, CT, USA
| | - S Percy Ivy
- Cancer Therapy Evaluation Program, National Cancer Institute, Bethesda, MD, USA
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12
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Myers CR. Enhanced targeting of mitochondrial peroxide defense by the combined use of thiosemicarbazones and inhibitors of thioredoxin reductase. Free Radic Biol Med 2016; 91:81-92. [PMID: 26686468 DOI: 10.1016/j.freeradbiomed.2015.12.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 12/02/2015] [Accepted: 12/09/2015] [Indexed: 11/22/2022]
Abstract
Peroxiredoxin-3 (Prx3) accounts for about 90% of mitochondrial peroxidase activity, and its marked upregulation in many cancers is important for cell survival. Prx3 oxidation can critically alter peroxide signaling and defense and can be a seminal event in promoting cell death. Here it is shown that this mechanism can be exploited pharmacologically by combinations of clinically available drugs that compromise Prx3 function in different ways. Clinically relevant levels of the thiosemicarbazone iron chelators triapine (Tp) and 2,2'-Dipyridyl-N,N-dimethylsemicarbazone (Dp44mT) promote selective oxidation of mitochondrial Prx3, but not cytosolic Prx1, in multiple human lung and ovarian cancer lines. Decreased cell survival closely correlates with Prx3 oxidation. However, Prx3 oxidation is not merely an indicator of cell death as cytotoxic concentrations of cisplatin do not cause Prx3 oxidation. The siRNA-mediated suppression of either Prx3 or thioredoxin-2, which supports Prx3, enhances Tp's cytotoxicity. Tp-mediated Prx3 oxidation is driven by enhanced peroxide generation, but not by nitric oxide. Many tumors overexpress thioredoxin reductase (TrxR) which supports Prx activity. Direct inhibitors of TrxR (e.g. auranofin, cisplatin) markedly enhanced Tp's cytotoxicity, and auranofin enhanced Prx3 oxidation by low dose Tp. Together, these results support an important role for Prx3 oxidation in the cytotoxicity of Tp, and demonstrate that TrxR inhibitors can significantly enhance Tp's cytotoxicity. Thiosemicarbazone-based regimens could prove effective for targeting Prx3 in a variety of cancers.
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Affiliation(s)
- Charles R Myers
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Free Radical Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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13
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Pelivan K, Miklos W, van Schoonhoven S, Koellensperger G, Gille L, Berger W, Heffeter P, Kowol CR, Keppler BK. Differences in protein binding and excretion of Triapine and its Fe(III) complex. J Inorg Biochem 2015; 160:61-9. [PMID: 26507768 DOI: 10.1016/j.jinorgbio.2015.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 09/02/2015] [Accepted: 10/05/2015] [Indexed: 11/26/2022]
Abstract
Triapine has been investigated as anticancer drug in multiple clinical phase I/II trials. Although promising anti-leukemic activity was observed, Triapine was ineffective against solid tumors. The reasons are currently widely unknown. The biological activity of Triapine is strongly connected to its iron complex (Fe-Triapine) which is pharmacologically not investigated. Here, novel analytical tools for Triapine and Fe-Triapine were developed and applied for cell extracts and body fluids of treated mice. Triapine and its iron complex showed a completely different behavior: for Triapine, low protein binding was observed in contrast to fast protein adduct formation of Fe-Triapine. Notably, both drugs were rapidly cleared from the body (serum half-life time <1h). Remarkably, in contrast to Triapine, where (in accordance to clinical data) basically no renal excretion was found, the iron complex was effectively excreted via urine. Moreover, no Fe-Triapine was detected in serum or cytosolic extracts after Triapine treatment. Taken together, our study will help to further understand the biological behavior of Triapine and its Fe-complex and allow the development of novel thiosemicarbazones with pronounced activity against solid tumor types.
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Affiliation(s)
- Karla Pelivan
- Institute of Inorganic Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria
| | - Walter Miklos
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Sushilla van Schoonhoven
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Gunda Koellensperger
- Institute of Analytical Chemistry, University of Vienna, Waehringer Strasse 38, 1090 Vienna, Austria
| | - Lars Gille
- Institute of Pharmacology and Toxicology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Walter Berger
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Petra Heffeter
- Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", University of Vienna and Medical University of Vienna, Vienna, Austria.
| | - Christian R Kowol
- Institute of Inorganic Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", University of Vienna and Medical University of Vienna, Vienna, Austria.
| | - Bernhard K Keppler
- Institute of Inorganic Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", University of Vienna and Medical University of Vienna, Vienna, Austria
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14
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Miklos W, Pelivan K, Kowol CR, Pirker C, Dornetshuber-Fleiss R, Spitzwieser M, Englinger B, van Schoonhoven S, Cichna-Markl M, Koellensperger G, Keppler BK, Berger W, Heffeter P. Triapine-mediated ABCB1 induction via PKC induces widespread therapy unresponsiveness but is not underlying acquired triapine resistance. Cancer Lett 2015; 361:112-20. [PMID: 25749419 DOI: 10.1016/j.canlet.2015.02.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/26/2015] [Accepted: 02/26/2015] [Indexed: 10/23/2022]
Abstract
Although triapine is promising for treatment of advanced leukemia, it failed against solid tumors due to widely unknown reasons. To address this issue, a new triapine-resistant cell line (SW480/tria) was generated by drug selection and investigated in this study. Notably, SW480/tria cells displayed broad cross-resistance against several known ABCB1 substrates due to high ABCB1 levels (induced by promoter hypomethylation). However, ABCB1 inhibition did not re-sensitize SW480/tria cells to triapine and subsequent analysis revealed that triapine is only a weak ABCB1 substrate without significant interaction with the ABCB1 transport function. Interestingly, in chemo-naive, parental SW480 cells short-time (24 h) treatment with triapine stimulated ABCB1 expression. These effects were based on activation of protein kinase C (PKC), a known response to cellular stress. In accordance, SW480/tria cells were characterized by elevated levels of PKC. Together, this led to the conclusion that increased ABCB1 expression is not the major mechanism of triapine resistance in SW480/tria cells. In contrast, increased ABCB1 expression was found to be a consequence of triapine stress-induced PKC activation. These data are especially of importance when considering the choice of chemotherapeutics for combination with triapine.
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Affiliation(s)
- W Miklos
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - K Pelivan
- Institute of Inorganic Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", Vienna, Austria
| | - C R Kowol
- Institute of Inorganic Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", Vienna, Austria
| | - C Pirker
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - R Dornetshuber-Fleiss
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria; Department of Pharmacology and Toxicology, University of Vienna, Althanstraße 14, A-1090 Vienna, Austria
| | - M Spitzwieser
- Department of Analytical Chemistry, University of Vienna, Waehringer Str. 38, A-1090 Vienna, Austria
| | - B Englinger
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - S van Schoonhoven
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - M Cichna-Markl
- Department of Analytical Chemistry, University of Vienna, Waehringer Str. 38, A-1090 Vienna, Austria
| | - G Koellensperger
- Department of Analytical Chemistry, University of Vienna, Waehringer Str. 38, A-1090 Vienna, Austria
| | - B K Keppler
- Institute of Inorganic Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", Vienna, Austria
| | - W Berger
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", Vienna, Austria
| | - P Heffeter
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria; Research Platform "Translational Cancer Therapy Research", Vienna, Austria.
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