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Weng C, Shen L, Ang WH. Harnessing Endogenous Formate for Antibacterial Prodrug Activation by
in cellulo
Ruthenium‐Mediated Transfer Hydrogenation Reaction. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Ong JX, Ang WH. Development of a Pre‐assembled Through‐Bond Energy Transfer (TBET) Fluorescent Probe for Ratiometric Sensing of Anticancer Platinum(ll) Complexes. Chem Asian J 2020; 15:1449-1455. [DOI: 10.1002/asia.202000157] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/06/2020] [Indexed: 01/28/2023]
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Ang WH, Xing B. AsBIC-9: The 9th Asian Biological Inorganic Chemistry Conference: Overview. J Inorg Biochem 2020; 202:110861. [DOI: 10.1016/j.jinorgbio.2019.110861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Li J, Yap SQ, Yoong SL, Nayak TR, Chandra GW, Ang WH, Panczyk T, Ramaprabhu S, Vashist SK, Sheu FS, Tan A, Pastorin G. Carbon nanotube bottles for incorporation, release and enhanced cytotoxic effect of cisplatin. CARBON 2019; 50:1625-1634. [PMID: 31105316 PMCID: PMC6522380 DOI: 10.1016/j.carbon.2011.11.043] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Carbon nanotubes (CNTs) have emerged as promising drug delivery systems particularly for cancer therapy, due to their abilities to overcome some of the challenges faced by cancer treatment, namely non-specificity, poor permeability into tumour tissues, and poor stability of anticancer drugs. Encapsulation of anticancer agents inside CNTs provides protection from external deactivating agents. However, the open ends of the CNTs leave the encapsulated drugs exposed to the environment and eventually their uncontrolled release before reaching the desired target. In this study, we report the successful encapsulation of cisplatin, a FDA-approved chemotherapeutic drug, into multi-walled carbon nanotubes and the capping at the ends with functionalised gold nanoparticles to achieve a "carbon nanotube bottle" structure. In this proof-of-concept study, these caps did not prevent the encapsulation of drug in the inner space of CNTs; on the contrary, we achieved higher drug loading inside the nanotubes in comparison with data reported in literature. In addition, we demonstrated that encapsulated cisplatin could be delivered in living cells under physiological conditions to exert its pharmacological action.
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Babak MV, Zhi Y, Czarny B, Toh TB, Hooi L, Chow EKH, Ang WH, Gibson D, Pastorin G. Dual-Targeting Dual-Action Platinum(IV) Platform for Enhanced Anticancer Activity and Reduced Nephrotoxicity. Angew Chem Int Ed Engl 2019; 58:8109-8114. [PMID: 30945417 DOI: 10.1002/anie.201903112] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Indexed: 01/16/2023]
Abstract
A novel and highly efficient dual-targeting platform was designed to ensure targeted in vivo delivery of dual-action PtIV prodrugs. The dual targeting was established by liposomal encapsulation of PtIV complexes, thereby utilizing the enhanced permeability and retention (EPR) effect as the first stage of targeting to attain a high accumulation of the drug-loaded liposomes in the tumor. After the release of the PtIV prodrug inside cancer cells, a second stage of targeting directed a portion of the PtIV prodrugs to the mitochondria. Upon intracellular reduction, these PtIV prodrugs released two bioactive molecules, acting both on the mitochondrial and on the nuclear DNA. Our PtIV system showed excellent activity in vitro and in vivo, characterized by a cytotoxicity in a low micromolar range and complete tumor remission, respectively. Notably, marked in vivo activity was accompanied by reduced kidney toxicity, highlighting the unique therapeutic potential of our novel dual-targeting dual-action platform.
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Lee VEY, Chin CF, Ang WH. Design and investigation of photoactivatable platinum(iv) prodrug complexes of cisplatin. Dalton Trans 2019; 48:7388-7393. [PMID: 30957798 DOI: 10.1039/c9dt00540d] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Platinum(iv) carboxylate scaffolds have garnered considerable research interest because they can be engineered to function as prodrugs of clinical platinum(ii) anticancer drugs. These platinum(iv) prodrug complexes are stable and tunable, and activated by reduction to release their cytotoxic platinum(ii) cargo. Here we propose new platinum(iv) prodrug complexes designed to release cisplatin via photoreduction upon UV irradiation. The central strategy is to utilise aryl carboxylate ligands on the axial positions of that platinum(iv) scaffold that confer significant UV absorption and would stabilise carboxyl radical formation, thus favouring homolytic Pt-O bond cleavage. We isolated and identified aryl carboxyl radicals via spin-trapping and showed that the photoreduced platinum species mirror cisplatin reactivity toward DNA bases, thereby validating the efficacy of this approach.
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Ong JX, Lim CSQ, Le HV, Ang WH. A Ratiometric Fluorescent Probe for Cisplatin: Investigating the Intracellular Reduction of Platinum(IV) Prodrug Complexes. Angew Chem Int Ed Engl 2018; 58:164-167. [PMID: 30407697 DOI: 10.1002/anie.201810361] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 10/15/2018] [Indexed: 01/02/2023]
Abstract
The PtIV prodrug strategy has emerged as an excellent alternative to tackle the problems associated with conventional PtII drug therapy. However, there is a lack of tools to study how this new class of PtIV drugs are processed at the cellular level. Herein, we report the first ratiometric probe for cisplatin detection and use it to investigate PtIV anticancer complexes in biological systems. The probe was able to distinguish between cisplatin and its PtIV derivatives, allowing us to probe the intracellular reduction of PtIV prodrug complexes. The correlation between the amount of active PtII species available after intracellular reduction of PtIV complexes and their cytotoxicity and the role glutathione plays in the reduction of PtIV complexes were investigated.
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Ong JX, Lim CSQ, Le HV, Ang WH. A Ratiometric Fluorescent Probe for Cisplatin: Investigating the Intracellular Reduction of Platinum(IV) Prodrug Complexes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810361] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Orlowska E, Babak MV, Dömötör O, Enyedy EA, Rapta P, Zalibera M, Bučinský L, Malček M, Govind C, Karunakaran V, Farid YCS, McDonnell TE, Luneau D, Schaniel D, Ang WH, Arion VB. NO Releasing and Anticancer Properties of Octahedral Ruthenium–Nitrosyl Complexes with Equatorial 1H-Indazole Ligands. Inorg Chem 2018; 57:10702-10717. [DOI: 10.1021/acs.inorgchem.8b01341] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Sîrbu A, Palamarciuc O, Babak MV, Lim JM, Ohui K, Enyedy EA, Shova S, Darvasiová D, Rapta P, Ang WH, Arion VB. Copper(ii) thiosemicarbazone complexes induce marked ROS accumulation and promote nrf2-mediated antioxidant response in highly resistant breast cancer cells. Dalton Trans 2018; 46:3833-3847. [PMID: 28271099 DOI: 10.1039/c7dt00283a] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A series of water-soluble sodium salts of 3-formyl-4-hydroxybenzenesulfonic acid thiosemicarbazones (or sodium 5-sulfonate-salicylaldehyde thiosemicarbazones) containing different substituents at the terminal nitrogen atom (H, Me, Et, Ph) and their copper(ii) complexes have been prepared and characterised by elemental analysis, spectroscopic techniques (IR, UV-vis, 1H NMR), ESI mass spectrometry, X-ray crystallography and cyclic voltammetry. The proligands and their copper(ii) complexes exhibit moderate water solubility and good stability in aqueous environment, determined by investigating their proton dissociation and complex formation equilibria. The copper(ii) complexes showed moderate anticancer activity in established human cancer cell lines, while the proligands were devoid of cytotoxicity. The anticancer activity of the copper(ii) complexes correlates with their ability to induce ROS accumulation in cells, consistent with their redox potentials within the biological window, triggering the activation of antioxidation defense mechanisms in response to the ROS insult. These studies pave the way for the investigation of ROS-inducing copper(ii) complexes as prospective antiproliferative agents in cancer chemotherapy.
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Chow MJ, Babak MV, Tan KW, Cheong MC, Pastorin G, Gaiddon C, Ang WH. Induction of the Endoplasmic Reticulum Stress Pathway by Highly Cytotoxic Organoruthenium Schiff-Base Complexes. Mol Pharm 2018; 15:3020-3031. [PMID: 29979603 DOI: 10.1021/acs.molpharmaceut.8b00003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Current anticancer drug discovery efforts focus on the identification of first-in-class compounds with a mode-of-action distinct from conventional DNA-targeting agents for chemotherapy. An emerging trend is the identification of endoplasmic reticulum (ER) targeting compounds that induce ER stress in cancer cells, leading to cell death. However, a limited pool of such compounds has been identified to date, and there are limited studies done on such compounds to allow for the rational design of ER stress-inducing agents. In our present study, we present a series of highly cytotoxic, ER stress-inducing Ru(II)-arene Schiff-Base (RAS) complexes, bearing iminoquinoline chelate ligands. We demonstrate that by structural modification to the iminoquinoline ligand, we could tune its π-acidity and influence reactive oxygen species (ROS) induction, switching between a ROS-mediated ER stress pathway activation and one that is not mediated by ROS induction. Our current study adds to the available ER stress inducers and shows how structural tuning could be used as a means to modulate the mode-of-action of such compounds.
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Lee KGZ, Babak MV, Weiss A, Dyson PJ, Nowak-Sliwinska P, Montagner D, Ang WH. Development of an Efficient Dual-Action GST-Inhibiting Anticancer Platinum(IV) Prodrug. ChemMedChem 2018; 13:1210-1217. [PMID: 29637702 DOI: 10.1002/cmdc.201800105] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/27/2018] [Indexed: 01/19/2023]
Abstract
The cytotoxicity of cisplatin (cDDP) is enhanced when co-administered with ethacrynic acid (EA), a glutathione S-transferase (GST) inhibitor. A PtIV -EA conjugate containing a cDDP core and two axial ethacrynate ligands (compound 1) was shown to be an excellent inhibitor of GST, but did not readily release a PtII species to exert a synergistic cytotoxic effect. In this study, a redesigned PtIV construct composed of a cDDP core with one axial ethacrynate ligand and one axial hydroxido ligand (compound 2) was prepared and shown to overcome the limitations of compound 1. The EA ligand in 2 is readily released in vitro together with a cytotoxic PtII species derived from cisplatin, working together to inhibit cell proliferation in cDDP-resistant human ovarian cancer cells. The in vitro activity translates well in vivo with 2, showing effective (∼80 %) inhibition of tumor growth in a human ovarian carcinoma A2780 tumor model, while showing considerably lower toxicity than cisplatin, thus validating the new design strategy.
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De S, Babak MV, Hülsey MJ, Ang WH, Yan N. Designed Precursor for the Controlled Synthesis of Highly Active Atomic and Sub-nanometric Platinum Catalysts on Mesoporous Silica. Chem Asian J 2018; 13:1053-1059. [DOI: 10.1002/asia.201800125] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 02/20/2018] [Indexed: 11/12/2022]
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Babak MV, Ang WH. Multinuclear Organometallic Ruthenium-Arene Complexes for Cancer Therapy. Met Ions Life Sci 2018; 18:/books/9783110470734/9783110470734-007/9783110470734-012.xml. [PMID: 29394025 DOI: 10.1515/9783110470734-012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
There has been much recent interest in the development of therapeutic transition metal-based complexes in part fueled by the clinical success of the platinum(II) anticancer drug, cisplatin. Yet known platinum drugs are limited by their high toxicity, severe side-effects, and incidences of drug resistance. Organometallic ruthenium-arene complexes have risen to prominence as a pharmacophore due to the success of other ruthenium drug candidates in clinical trials. In this chapter, we highlight higher order multinuclear ruthenium-arene complexes and their respective investigations as chemotherapeutic agents. We discuss their unique structural properties and the associated biochemical evaluation in the context of anticancer drug design. We also review the structural considerations for the design of these scaffolds and new therapeutic applications that are uncovered for this class of complexes.
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Ong JX, Pang VYT, Tng LM, Ang WH. Pre-Assembled Coumarin-Rhodamine Scaffold for Ratiometric Sensing of Nitric Oxide and Hypochlorite. Chemistry 2018; 24:1870-1876. [DOI: 10.1002/chem.201703554] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Indexed: 01/11/2023]
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Chow MJ, Alfiean M, Pastorin G, Gaiddon C, Ang WH. Apoptosis-independent organoruthenium anticancer complexes that overcome multidrug resistance: self-assembly and phenotypic screening strategies. Chem Sci 2017; 8:3641-3649. [PMID: 30155208 PMCID: PMC6094174 DOI: 10.1039/c7sc00497d] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 02/22/2017] [Indexed: 01/20/2023] Open
Abstract
Multidrug resistance is a major impediment to chemotherapy and limits the efficacies of conventional anticancer drugs. A strategy to bypass multidrug resistance is to develop new drug candidates capable of inducing apoptosis-independent programmed cell death. However, cellular pathways implicated in alternative programmed cell death are not well-elucidated and multifactorial, making a target-based discovery approach a challenge. Here, we show that a coordination-directed three-component assembly and phenotypic screening strategy could be employed as a viable alternative for the identification of apoptosis-independent organoruthenium anticancer agents. Through an on-plate synthesis and screening of 195 organoruthenium complexes against apoptosis-sensitive and -resistant cancers, we identified two apoptosis-independent hits. Subsequent validation of the two hits showed a lack of induction of apoptotic biomarkers, a caspase-independent activity and an equal efficacy in both apoptosis-sensitive and -resistant colorectal cancers. This validated their apoptosis-independent modes-of-action, paving the way as potential candidates for the treatment of highly-refractory cancer phenotypes.
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Yap SQ, Chin CF, Hong Thng AH, Pang YY, Ho HK, Ang WH. Finely Tuned Asymmetric Platinum(IV) Anticancer Complexes: Structure-Activity Relationship and Application as Orally Available Prodrugs. ChemMedChem 2017; 12:300-311. [PMID: 28028938 DOI: 10.1002/cmdc.201600577] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/22/2016] [Indexed: 01/12/2023]
Abstract
Platinum(IV) bis-carboxylates are highly versatile prodrug scaffolds with different axial ligands that can be functionalized while keeping the platinum(II) pharmacophore intact. Using a sequential acylation strategy, we developed a class of PtIV prodrugs of cisplatin with contrasting lipophilic and hydrophilic ligands. We investigated their stability, reduction rates, lipophilicity, aqueous solubility, and antiproliferative efficacies, and assessed for correlations among the parameters that could be useful in drug design. We showed that compounds with high lipophilicity result in better antiproliferative effects in vitro and in vivo, with one of the three compounds tested showing better efficacy than satraplatin against an animal model of colorectal cancer, owing to its higher solubility and lower reduction rates. Our asymmetric PtIV prodrugs may pave the way for a highly predictable, fine-tuned class of orally available PtIV prodrugs for the treatment of colorectal cancer.
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Tram DTN, Wang H, Sugiarto S, Li T, Ang WH, Lee C, Pastorin G. Advances in nanomaterials and their applications in point of care (POC) devices for the diagnosis of infectious diseases. Biotechnol Adv 2016; 34:1275-1288. [PMID: 27686397 PMCID: PMC7127209 DOI: 10.1016/j.biotechadv.2016.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 07/13/2016] [Accepted: 09/23/2016] [Indexed: 01/17/2023]
Abstract
Nanotechnology has gained much attention over the last decades, as it offers unique opportunities for the advancement of the next generation of sensing tools. Point-of-care (POC) devices for the selective detection of biomolecules using engineered nanoparticles have become a main research thrust in the diagnostic field. This review presents an overview on how the POC-associated nanotechnology, currently applied for the identification of nucleic acids, proteins and antibodies, might be further exploited for the detection of infectious pathogens: although still premature, future integrations of nanoparticles with biological markers that target specific microorganisms will enable timely therapeutic intervention against life-threatening infectious diseases.
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Chow MJ, Licona C, Pastorin G, Mellitzer G, Ang WH, Gaiddon C. Structural tuning of organoruthenium compounds allows oxidative switch to control ER stress pathways and bypass multidrug resistance. Chem Sci 2016; 7:4117-4124. [PMID: 30155055 PMCID: PMC6013925 DOI: 10.1039/c6sc00268d] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/25/2016] [Indexed: 12/12/2022] Open
Abstract
Multidrug resistance (MDR) is a major impediment to the success of chemotherapy in many cancer types. One particular MDR mechanism is the inherent or acquired adaptation of the cellular survival pathways that render malignant cells resistant to apoptotic cell death. Since most drugs act through apoptosis, compounds capable of inducing alternative forms of programmed cell death (PCD) can potentially be harnessed to bypass MDR. We investigated two organoruthenium complexes, RAS-1H and RAS-1T, and demonstrated that although they both induced non-apoptotic PCD through ER stress pathways, their modes-of-action were drastically different despite modest structural variations. RAS-1T acted through ROS-mediated ER stress while RAS-1H was ROS-independent. We further showed that they were more efficacious against apoptosis-resistant cells compared to clinical drugs including oxaliplatin. This work provides the basis for underpinning ER stress modulation using metal complexes to bypass apoptosis resistance.
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Chow MJ, Babak MV, Wong DYQ, Pastorin G, Gaiddon C, Ang WH. Structural Determinants of p53-Independence in Anticancer Ruthenium-Arene Schiff-Base Complexes. Mol Pharm 2016; 13:2543-54. [PMID: 27174050 DOI: 10.1021/acs.molpharmaceut.6b00348] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
p53 is a key tumor suppressor gene involved in key cellular processes and implicated in cancer therapy. However, it is inactivated in more than 50% of all cancers due to mutation or overexpression of its negative regulators. This leads to drug resistance and poor chemotherapeutic outcome as most clinical drugs act via a p53-dependent mechanism of action. An attractive strategy to circumvent this resistance would be to identify new anticancer drugs that act via p53-independent mode of action. In the present study, we identified 9 Ru (II)-Arene Schiff-base (RAS) complexes able to induce p53-independent cytotoxicity and discuss structural features that are required for their p53-independent activity. Increasing hydrophobicity led to an increase in cellular accumulation in cells with a corresponding increase in efficacy. We further showed that all nine complexes demonstrated p53-independent activity. This was despite significant differences in their physicochemical properties, suggesting that the iminoquinoline ligand, a common structural feature for all the complexes, is required for the p53-independent activity.
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Nguyen TTT, Lim YJ, Fan MHM, Jackson RA, Lim KK, Ang WH, Ban KHK, Chen ES. Calcium modulation of doxorubicin cytotoxicity in yeast and human cells. Genes Cells 2016; 21:226-40. [DOI: 10.1111/gtc.12346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/29/2015] [Indexed: 12/16/2022]
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Nguyen TTT, Chua JKK, Seah KS, Koo SH, Yee JY, Yang EG, Lim KK, Pang SYW, Yuen A, Zhang L, Ang WH, Dymock B, Lee EJD, Chen ES. Predicting chemotherapeutic drug combinations through gene network profiling. Sci Rep 2016; 6:18658. [PMID: 26791325 PMCID: PMC4726371 DOI: 10.1038/srep18658] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 11/23/2015] [Indexed: 12/29/2022] Open
Abstract
Contemporary chemotherapeutic treatments incorporate the use of several agents in combination. However, selecting the most appropriate drugs for such therapy is not necessarily an easy or straightforward task. Here, we describe a targeted approach that can facilitate the reliable selection of chemotherapeutic drug combinations through the interrogation of drug-resistance gene networks. Our method employed single-cell eukaryote fission yeast (Schizosaccharomyces pombe) as a model of proliferating cells to delineate a drug resistance gene network using a synthetic lethality workflow. Using the results of a previous unbiased screen, we assessed the genetic overlap of doxorubicin with six other drugs harboring varied mechanisms of action. Using this fission yeast model, drug-specific ontological sub-classifications were identified through the computation of relative hypersensitivities. We found that human gastric adenocarcinoma cells can be sensitized to doxorubicin by concomitant treatment with cisplatin, an intra-DNA strand crosslinking agent, and suberoylanilide hydroxamic acid, a histone deacetylase inhibitor. Our findings point to the utility of fission yeast as a model and the differential targeting of a conserved gene interaction network when screening for successful chemotherapeutic drug combinations for human cells.
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Ong JX, Yap JY, Yap SQ, Ang WH. Structure-activity relationship studies on rhodamine B-based fluorogenic probes and their activation by anticancer platinum(II) compounds. J Inorg Biochem 2015; 153:272-278. [PMID: 26518138 DOI: 10.1016/j.jinorgbio.2015.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 10/02/2015] [Accepted: 10/05/2015] [Indexed: 01/27/2023]
Abstract
Fluorescence microscopy has emerged as an attractive technique for imaging intracellular Pt species arising from exposure to clinical anticancer drugs such as cisplatin. A rhodamine-B based fluorogenic probe termed Rho-DDTC can be activated selectively in the presence of Pt(II) compounds, and possesses the ability to discriminate Pt(II) species from Pt(IV) carboxylate prodrug complexes, thereby providing a unique platform to investigate the reduction of these Pt(IV) complexes after cell entry. In this report, we seek to establish the mechanism of activation of Rho-DDTC through a structure-activity relationship study on its structural analogues.
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Bi X, Adriani G, Xu Y, Chakrabortty S, Pastorin G, Ho HK, Ang WH, Chan Y. Gene Detection in Complex Biological Media Using Semiconductor Nanorods within an Integrated Microfluidic Device. Anal Chem 2015; 87:10292-8. [PMID: 26382664 DOI: 10.1021/acs.analchem.5b01942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The salient optical properties of highly luminescent semiconductor nanocrystals render them ideal fluorophores for clinical diagnostics, therapeutics, and highly sensitive biochip applications. Microfluidic systems allow miniaturization and integration of multiple biochemical processes in a single device and do not require sophisticated diagnostic tools. Herein, we describe a microfluidic system that integrates RNA extraction, reverse transcription to cDNA, amplification and detection within one integrated device to detect histidine decarboxylase (HDC) gene directly from human white blood cells samples. When anisotropic semiconductor nanorods (NRs) were used as the fluorescent probes, the detection limit was found to be 0.4 ng of total RNA, which was much lower than that obtained using spherical quantum dots (QDs) or organic dyes. This was attributed to the large action cross-section of NRs and their high probability of target capture in a pull-down detection scheme. The combination of large scale integrated microfluidics with highly fluorescent semiconductor NRs may find widespread utility in point-of-care devices and multitarget diagnostics.
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Chua EYD, Davey GE, Chin CF, Dröge P, Ang WH, Davey CA. Stereochemical control of nucleosome targeting by platinum-intercalator antitumor agents. Nucleic Acids Res 2015; 43:5284-96. [PMID: 25916851 PMCID: PMC4477649 DOI: 10.1093/nar/gkv356] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/02/2015] [Indexed: 11/15/2022] Open
Abstract
Platinum-based anticancer drugs act therapeutically by forming DNA adducts, but suffer from severe toxicity and resistance problems, which have not been overcome in spite of decades of research. And yet defined chromatin targets have generally not been considered in the drug development process. Here we designed novel platinum-intercalator species to target a highly deformed DNA site near the nucleosome center. Between two seemingly similar structural isomers, we find a striking difference in DNA site selectivity in vitro, which comes about from stereochemical constraints that limit the reactivity of the trans isomer to special DNA sequence elements while still allowing the cis isomer to efficiently form adducts at internal sites in the nucleosome core. This gives the potential for controlling nucleosome site targeting in vivo, which would engender sensitivity to epigenetic distinctions and in particular cell type/status-dependent differences in nucleosome positioning. Moreover, while both compounds yield very similar DNA-adduct structures and display antitumor cell activity rivalling that of cisplatin, the cis isomer, relative to the trans, has a much more rapid cytotoxic effect and distinct impact on cell function. The novel stereochemical principles for controlling DNA site selectivity we discovered could aid in the design of improved site discriminating agents.
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