51
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Saleh MM, Laughton CA, Bradshaw TD, Moody CJ. Development of a series of bis-triazoles as G-quadruplex ligands. RSC Adv 2017. [DOI: 10.1039/c7ra07257k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Maintenance of telomeres – specialized complexes that protect the ends of chromosomes – is provided by the enzyme complex telomerase, which is a key factor that is activated in more than 80% of cancer cells, but absent in most normal cells.
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52
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Cini M, Bradshaw TD, Woodward S. Using titanium complexes to defeat cancer: the view from the shoulders of titans. Chem Soc Rev 2017; 46:1040-1051. [DOI: 10.1039/c6cs00860g] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Seeking ‘unifying mechanisms of action’ in titanium anti-cancer agents: a 40 year odyssey.
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53
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Cini M, Williams H, Fay MW, Searle MS, Woodward S, Bradshaw TD. Enantiopure titanocene complexes--direct evidence for paraptosis in cancer cells. Metallomics 2016; 8:286-97. [PMID: 26806372 DOI: 10.1039/c5mt00297d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tolerated by normal tissues, anti-cancer therapies based on titanium compounds are limited by low efficacy/selectivity and lack of understanding of their mode(s) of action. In vitro antitumour activity and mode of cell death incurred by enantiopure TiCl2{η-C5H4CHEt(2-MeOPh)}2 (abbreviated Cp(R)2TiCl2) has been investigated. The in vitro anti-tumour activity of Cp(R)2TiCl2 is selective for cancer cells; in clonogenic assays, (S,S)-Cp(R)2TiCl2 was twice as effective at inhibiting colony formation than other stereoisomers after 24 h exposure. HPLC, MS and NMR techniques determined hydrolysis of Cp(R)2TiCl2; data strongly correlate with soluble [Cp(R)2Ti(OH)(OH2)](+) being the biological trigger. Treatment of cells with Cp(R)2TiCl2 provoked extensive cytoplasmic vacuolization, endoplasmic reticulum (ER) swelling and activation of MAPKinase signal transduction, consistent with ligand-induced paraptosis, type III cell death, which is morphologically distinct from, and independent of apoptosis. Indeed, distinct from cisplatin, Cp(R)2TiCl2 failed to perturb cell cycle dynamics, induce γH2AX foci or evoke apoptosis in MDA-MB-468 and HCT-116 cells.
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54
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Skilling KJ, Kellam B, Ashford M, Bradshaw TD, Marlow M. Developing a self-healing supramolecular nucleoside hydrogel. SOFT MATTER 2016; 12:8950-8957. [PMID: 27714367 DOI: 10.1039/c6sm01779g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Low molecular weight gelator hydrogels provide a viable alternative to traditional polymer based drug delivery platforms, owing to their tunable stability and in most cases inherent biocompatibility. Here we report the first self-healing nucleoside hydrogel using N4-octanoyl-2'-deoxycytidine (0.5% w/v) for drug delivery. The hydrogel's cross-linked nanofibrillar structure, was characterised using oscillatory rheology and confirmed using SEM and TEM imaging. The potential of this gel for drug delivery was explored in vitro using fluorescently labelled tracers. Cell viability assays were conducted using pancreatic cell lines which tolerated the gels well; whilst no adverse effects on the viability or proliferation of cells were observed for fibroblast cell lines.
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Han LC, Stanley PA, Wood PJ, Sharma P, Kuruppu AI, Bradshaw TD, Moses JE. Horner-Wadsworth-Emmons approach to piperlongumine analogues with potent anti-cancer activity. Org Biomol Chem 2016; 14:7585-93. [PMID: 27443386 DOI: 10.1039/c6ob01160h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Natural products with anti-cancer activity play a vital role in lead and target discovery. We report here the synthesis and biological evaluation of the plant-derived alkaloid, piperlongumine and analogues. Using a Horner-Wadsworth-Emmons coupling approach, a selection of piperlongumine-like compounds were prepared in good overall yield from a novel phosphonoacetamide reagent. A number of the compounds displayed potent anti-cancer activity against colorectal (HCT 116) and ovarian (IGROV-1) carcinoma cell lines, via a mechanism of action which may involve ROS generation. Contrary to previous reports, no selective action in cancer cell (MRC-5) was observed for piperlongumine analogues.
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Cini M, Williams H, Fay MW, Searle MS, Woodward S, Bradshaw TD. Correction: Enantiopure titanocene complexes--direct evidence for paraptosis in cancer cells. Metallomics 2016; 8:260. [PMID: 26847676 DOI: 10.1039/c6mt90005d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for 'Enantiopure titanocene complexes--direct evidence for paraptosis in cancer cells' by Melchior Cini et al., Metallomics, 2016, DOI: 10.1039/c5mt00297d.
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Qazzaz ME, Raja VJ, Lim KH, Kam TS, Lee JB, Gershkovich P, Bradshaw TD. In vitro anticancer properties and biological evaluation of novel natural alkaloid jerantinine B. Cancer Lett 2016; 370:185-97. [PMID: 26515390 DOI: 10.1016/j.canlet.2015.10.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/08/2015] [Accepted: 10/09/2015] [Indexed: 01/13/2023]
Abstract
Natural products play a pivotal role in medicine especially in the cancer arena. Many drugs that are currently used in cancer chemotherapy originated from or were inspired by nature. Jerantinine B (JB) is one of seven novel Aspidosperma indole alkaloids isolated from the leaf extract of Tabernaemontana corymbosa. Preliminary antiproliferative assays revealed that JB and JB acetate significantly inhibited growth and colony formation, accompanied by time- and dose-dependent apoptosis induction in human cancer cell lines. JB significantly arrested cells at the G2/M cell cycle phase, potently inhibiting tubulin polymerisation. Polo-like kinase 1 (PLK1; an early trigger for the G2/M transition) was also dose-dependently inhibited by JB (IC50 1.5 µM). Furthermore, JB provoked significant increases in reactive oxygen species (ROS). Annexin V+ cell populations, dose-dependent accumulation of cleaved-PARP and caspase 3/7 activation, and reduced Bcl-2 and Mcl-1 expression confirm apoptosis induction. Preclinical in silico biopharmaceutical assessment of JB calculated rapid absorption and bioavailability >70%. Doses of 8-16 mg/kg JB were predicted to maintain unbound plasma concentrations >GI50 values in mice during efficacy studies. These findings advocate continued development of JB as a potential chemotherapeutic agent.
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58
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Cousin D, Zhang J, Hummersone MG, Matthews CS, Frigerio M, Bradshaw TD, Stevens MFG. Antitumor imidazo[5,1-d]-1,2,3,5-tetrazines: compounds modified at the 3-position overcome resistance in human glioblastoma cell lines. MEDCHEMCOMM 2016. [DOI: 10.1039/c6md00384b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Imidazotetrazines substituted at the N-3 position overcome resistance or tolerance to temozolomide conferred, respectively, by MGMT or DNA MMR defects.
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Kuruppu AI, Zhang L, Collins H, Turyanska L, Thomas NR, Bradshaw TD. An Apoferritin-based Drug Delivery System for the Tyrosine Kinase Inhibitor Gefitinib. Adv Healthc Mater 2015; 4:2816-21. [PMID: 26592186 DOI: 10.1002/adhm.201500389] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/21/2015] [Indexed: 12/24/2022]
Abstract
Anticancer drug Gefitinib encapsulated within human heavy chain apoferritin by diffusion allows pH-controlled sustained release of cargo. The combination of increased cellular uptake, and potent and enhanced antitumor activity against the HER2 overexpressing SKBR3 cell line compared to Gefitinib alone, makes it a promising carrier for delivery of drugs to tumor sites.
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60
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Stone EL, Citossi F, Singh R, Kaur B, Gaskell M, Farmer PB, Monks A, Hose C, Stevens MF, Leong CO, Stocks M, Kellam B, Marlow M, Bradshaw TD. Antitumour benzothiazoles. Part 32: DNA adducts and double strand breaks correlate with activity; synthesis of 5F203 hydrogels for local delivery. Bioorg Med Chem 2015; 23:6891-9. [DOI: 10.1016/j.bmc.2015.09.052] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/18/2015] [Accepted: 09/30/2015] [Indexed: 11/25/2022]
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61
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Cini M, Bradshaw TD, Woodward S, Lewis W. Asymmetric Pentafulvene Carbometalation--Access to Enantiopure Titanocene Dichlorides of Biological Relevance. Angew Chem Int Ed Engl 2015; 54:14179-82. [PMID: 26457574 DOI: 10.1002/anie.201508034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Indexed: 11/06/2022]
Abstract
Unprecedented asymmetric copper-catalyzed addition of ZnEt2 (ZnBu2) to the exocyclic C=C bond of pentafulvenes C5H4(=CHAr) (Ar=2-MeOPh and related species) results in enantiomerically enriched (up to 93:7 e.r.) cyclopentadienyl ligands (C5H4CHEtAr; abbreviated Cp(R)). Copper catalyst promotion with both chiral phosphoramidite ligands and a phosphate additive is vital in realizing both acceptable enantioselectivities and reaction rates. Enantiomeric Cp(R)2TiCl2 complexes have been prepared; the (S,S) isomer is twice as active towards pancreatic, breast, and colon cancer cell lines as its (R,R) enantiomer at 24 h.
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62
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Cini M, Bradshaw TD, Woodward S, Lewis W. Asymmetric Pentafulvene Carbometalation—Access to Enantiopure Titanocene Dichlorides of Biological Relevance. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201508034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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63
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Lim KH, Raja VJ, Bradshaw TD, Lim SH, Low YY, Kam TS. Ibogan, tacaman, and cytotoxic bisindole alkaloids from tabernaemontana. Cononusine, an iboga alkaloid with unusual incorporation of a pyrrolidone moiety. JOURNAL OF NATURAL PRODUCTS 2015; 78:1129-1138. [PMID: 25919190 DOI: 10.1021/acs.jnatprod.5b00117] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Six new indole alkaloids, viz., cononusine (1, a rare example of an iboga-pyrrolidone conjugate), ervaluteine (2), vincamajicine (3), tacamonidine (4), 6-oxoibogaine (5), and N(4)-chloromethylnorfluorocurarine chloride (6), and two new vobasinyl-iboga bisindole alkaloids, ervatensines A (7) and B (8), in addition to other known alkaloids, were isolated from the stem-bark extract of the Malayan Tabernaemontana corymbosa. The structures of these alkaloids were established on the basis of NMR and MS analyses and, in one instance (7), confirmed by X-ray diffraction analysis. Vincamajicine (3) showed appreciable activity in reversing multidrug resistance in vincristine-resistant KB cells (IC50 2.62 μM), while ervatensines A (7) and B (8) and two other known bisindoles displayed pronounced in vitro growth inhibitory activity against human KB cells (IC50 < 2 μM). Compounds 7 and 8 also showed good growth inhibitory activity against A549, MCF-7, MDA-468, HCT-116, and HT-29 cells (IC50 0.70-4.19 μM). Cell cycle and annexin V-FITC apoptosis assays indicated that compounds 7 and 8 inhibited proliferation of HCT-116 and MDA-468 cells, evoking apoptotic and necrotic cell death.
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64
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Bradshaw TD, Stevens MF, Calvert H, Plummer ER. Abstract B59: Preliminary clinical experiences of Phortress: Putative role for c‐MET inhibition in antitumor activity. Clin Trials 2014. [DOI: 10.1158/1535-7163.targ-09-b59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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65
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Lim SW, Loh HS, Ting KN, Bradshaw TD, Zeenathul NA. Antiproliferation and induction of caspase-8-dependent mitochondria-mediated apoptosis by β-tocotrienol in human lung and brain cancer cell lines. Biomed Pharmacother 2014; 68:1105-15. [PMID: 25456851 DOI: 10.1016/j.biopha.2014.10.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 10/06/2014] [Indexed: 11/18/2022] Open
Abstract
The pure vitamin isomer, β-tocotrienol has the least abundance among the other vitamin E isomers that are present in numerous plants. Hence, it is very scarcely studied for its bioactivity. In this study, the antiproliferative effects and primary apoptotic mechanisms of β-tocotrienol on human lung adenocarcinoma A549 and glioblastoma U87MG cells were investigated. It was evidenced that β-tocotrienol had inhibited the growth of both A549 (GI50=1.38±0.334μM) and U87MG (GI50=2.53±0.604μM) cells at rather low concentrations. Cancer cells incubated with β-tocotrienol were also found to exhibit hallmarks of apoptotic morphologies including membrane blebbing, chromatin condensation and formation of apoptotic bodies. The apoptotic properties of β-tocotrienol in both A549 and U87MG cells were the results of its capability to induce significant (P<0.05) double-strand DNA breaks (DSBs) without involving single-strand DNA breaks (SSBs). β-Tocotrienol is said to induce activation of caspase-8 in both A549 and U87MG cells guided by no activation when caspase-8 inhibitor, z-IETD-fmk was added. Besides, disruption on the mitochondrial membrane permeability of the cells in a concentration- and time-dependent manner had occurred. The induction of apoptosis by β-tocotrienol in A549 and U87MG cells was confirmed to involve both the death-receptor mediated and mitochondria-dependent apoptotic pathways. These findings could potentiate the palm oil derived β-tocotrienol to serve as a new anticancer agent for treating human lung and brain cancers.
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66
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Lu T, Laughton CA, Wang S, Bradshaw TD. In vitro antitumor mechanism of (E)-N-(2-methoxy-5-(((2,4,6-trimethoxystyryl)sulfonyl)methyl)pyridin-3-yl)methanesulfonamide. Mol Pharmacol 2014; 87:18-30. [PMID: 25316768 DOI: 10.1124/mol.114.093245] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ON01910.Na [sodium (E)-2-(2-methoxy-5-((2,4,6-trimethoxystyrylsulfonyl)methyl)phenylamino)acetate; Rigosertib, Estybon], a styryl benzylsulfone, is a phase III stage anticancer agent. This non-ATP competitive kinase inhibitor has multitargeted activity, promoting mitotic arrest and apoptosis. Extensive phase I/II studies with ON01910.Na, conducted in patients with solid tumors and hematologic cancers, demonstrate excellent efficacy. However, issues remain affecting its development. These include incomplete understanding of antitumor mechanisms, low oral bioavailability, and unpredictable pharmacokinetics. We have identified a novel (E)-styrylsulfonyl methylpyridine [(E)-N-(2-methoxy-5-((2,4,6-trimethoxystyrylsulfonyl)methyl)pyridin-3-yl)methanesulfonamide (TL-77)] which has shown improved oral bioavailability compared with ON01910.Na. Here, we present detailed cellular mechanisms of TL-77 in comparison with ON01910.Na. TL-77 displays potent growth inhibitory activity in vitro (GI50 < 1μM against HCT-116 cells), demonstrating 3- to 10-fold greater potency against tumor cell lines when compared with normal cells. Cell-cycle analyses reveal that TL-77 causes significant G2/M arrest in cancer cells, followed by the onset of apoptosis. In cell-free conditions, TL-77 potently inhibits tubulin polymerization. Mitotically arrested cells display multipolar spindles and misalignment of chromosomes, indicating that TL-77 interferes with mitotic spindle assembly in cancer cells. These effects are accompanied by induction of DNA damage, inhibition of Cdc25C phosphorylation [indicative of Plk1 inhibition], and downstream inhibition of cyclin B1. However, kinase assays failed to confirm inhibition of Plk1. Nonsignificant effects on phosphoinositide 3-kinase/Akt signal transduction were observed after TL-77 treatment. Analysis of apoptotic signaling pathways reveals that TL-77 downregulates expression of B-cell lymphoma 2 family proteins (Bid, Bcl-xl, and Mcl-1) and stimulates caspase activation. Taken together, TL-77 represents a promising anticancer agent worthy of further evaluation.
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Zhang J, Hummersone M, Matthews CS, Stevens MFG, Bradshaw TD. N3-substituted temozolomide analogs overcome methylguanine-DNA methyltransferase and mismatch repair precipitating apoptotic and autophagic cancer cell death. Oncology 2014; 88:28-48. [PMID: 25277441 DOI: 10.1159/000366131] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/24/2014] [Indexed: 11/19/2022]
Abstract
Glioblastoma multiforme (GBM) treatment includes temozolomide (TMZ) chemotherapy. O6-Methylguanine lesions are repaired by methylguanine-DNA methyltransferase (MGMT). Response to TMZ requires low MGMT and functional mismatch repair (MMR); resistance, conferred by MGMT or MMR deficiency, represents a barrier to successful treatment. TMZ analogs were synthesized, substituting N3-methyl with propargyl (1) or sulfoxide (2). MTT assays were conducted in SNB19 and U373 isogenic glioma cell lines (V = vector control; M = MGMT-transfected). TMZ potency was reduced >5-fold in SNB19M and U373M cells; in contrast, MGMT-expressing cells were equisensitive as vector controls to analogs 1 and 2 . GI50 values <50 μM of analogs 1 or 2 were detected in V cells possessing acquired TMZ resistance: SNB19VR (hMSH6 loss) and U373VR (MGMT upregulation). Analogs 1 and 2 inhibited MMR-deficient colorectal carcinoma cell growth (irrespective of p53); G2/M cell cycle arrest preceded apoptosis. γH2AX foci inferred the generation of DNA double-strand breaks by analogs 1 and 2 . Acridine orange-stained vesicles, intracellular punctate GFP-LC3 protein and double-membraned autophagosomes indicate that TMZ, 1 and 2 induce autophagy in apoptotis-resistant GBM cells. Analogs 1 and 2 elicit in vitro antitumor activity irrespective of MGMT, MMR and p53. Such imidazotetrazines may treat MGMT+ GBM and possess broader spectrum activity causing apoptosis and autophagy in malignancies which evade apoptosis.
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Lam F, Abbas AY, Shao H, Teo T, Adams J, Li P, Bradshaw TD, Fischer PM, Walsby E, Pepper C, Chen Y, Ding J, Wang S. Targeting RNA transcription and translation in ovarian cancer cells with pharmacological inhibitor CDKI-73. Oncotarget 2014; 5:7691-704. [PMID: 25277198 PMCID: PMC4202154 DOI: 10.18632/oncotarget.2296] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/31/2014] [Indexed: 01/09/2023] Open
Abstract
Dysregulation of cellular transcription and translation is a fundamental hallmark of cancer. As CDK9 and Mnks play pivotal roles in the regulation of RNA transcription and protein synthesis, respectively, they are important targets for drug development. We herein report the cellular mechanism of a novel CDK9 inhibitor CDKI-73 in an ovarian cancer cell line (A2780). We also used shRNA-mediated CDK9 knockdown to investigate the importance of CDK9 in the maintenance of A2780 cells. This study revealed that CDKI-73 rapidly inhibited cellular CDK9 kinase activity and down-regulated the RNAPII phosphorylation. This subsequently caused a decrease in the eIF4E phosphorylation by blocking Mnk1 kinase activity. Consistently, CDK9 shRNA was also found to down-regulate the Mnk1 expression. Both CDKI-73 and CDK9 shRNA decreased anti-apoptotic proteins Mcl-1 and Bcl-2 and induced apoptosis. The study confirmed that CDK9 is required for cell survival and that ovarian cancer may be susceptible to CDK9 inhibition strategy. The data also implied a role of CDK9 in eIF4E-mediated translational control, suggesting that CDK9 may have important implication in the Mnk-eIF4E axis, the key determinants of PI3K/Akt/mTOR- and Ras/Raf/MAPK-mediated tumorigenic activity. As such, CDK9 inhibitor drug candidate CDKI-73 should have a major impact on these pathways in human cancers.
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69
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Raja VJ, Lim KH, Leong CO, Kam TS, Bradshaw TD. Novel antitumour indole alkaloid, Jerantinine A, evokes potent G2/M cell cycle arrest targeting microtubules. Invest New Drugs 2014; 32:838-50. [DOI: 10.1007/s10637-014-0126-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 06/03/2014] [Indexed: 01/07/2023]
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Callero MA, Luzzani GA, De Dios DO, Bradshaw TD, Perez AIL. Biomarkers of sensitivity to potent and selective antitumor 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F203) in ovarian cancer. J Cell Biochem 2014; 114:2392-404. [PMID: 23696052 DOI: 10.1002/jcb.24589] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 05/01/2013] [Indexed: 12/20/2022]
Abstract
2-(4-Amino-3-methylphenyl)-5-fluorobenzothiazole (5F203, NSC 703786) lysylamide belongs to a novel mechanistic class of antitumor agents. It elicits activity against ovarian, breast, kidney and colorectal cancer models. In sensitive breast cancer cells, 5F203 activates aryl hydrocarbon receptor (AhR) signaling. Herein, we evaluate the role of AhR in 5F203 activity in two ovarian cancer cell lines: IGROV-1 (sensitive to 5F203), SKOV-3 (resistant to this agent). In addition, cancer cells have been isolated from ascites fluid of ovarian cancer patients; sensitivity to 5F203 and concurrent AhR signal transduction has been examined in ascites-isolated ovarian cancer patients' cells. 5F203 induced enhanced CYP1A1 expression, AhR translocation and ROS formation in IGROV-1 cells and ascites-isolated ovarian cancer cells that were sensitive to 5F203. In IGROV-1 cells 5F203-induced ROS formation was accompanied by JNK, ERK and P38MAPK phosphorylation, DNA damage and cell cycle arrest prior to apoptosis. In contrast, 5F203 failed to induce CYP1A1 expression, AhR translocation or oxidative stress in 5F203-resistant SKOV-3 cells, or in ovarian cancer ascites cells inherently resistant to this agent. We propose that AhR may represent a new molecular target in the treatment of ovarian tumors and 5F203 may exemplify a potential novel treatment. Furthermore, putative biomarkers of sensitivity to this agent have been identified.
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71
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Walsby E, Pratt G, Shao H, Abbas AY, Fischer PM, Bradshaw TD, Brennan P, Fegan C, Wang S, Pepper C. A novel Cdk9 inhibitor preferentially targets tumor cells and synergizes with fludarabine. Oncotarget 2014; 5:375-85. [PMID: 24495868 PMCID: PMC3964214 DOI: 10.18632/oncotarget.1568] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 12/18/2013] [Indexed: 01/22/2023] Open
Abstract
Cdk9 is a key elongation factor for RNA transcription and functions by phosphorylating the C-terminal domain of RNA polymerase II. Here we present direct evidence that cdk9 is important for cancer cell survival and describe the characterization of the potent cdk9 inhibitor CDKI-73 in primary human leukemia cells. CDKI-73 induced caspase-dependent apoptosis that was preceded by dephosphorylation of cdk9 and serine 2 of RNA polymerase II. CDKI-73 was more potent than the pan-cdk inhibitor flavopiridol and showed >200-fold selectivity against primary leukemia cells when compared with normal CD34+ cells. Furthermore, CDKI-73 was equipotent in poor prognostic sub-groups of leukemia patients and showed cytotoxic synergy with the nucleoside analog fludarabine. The Mechanism of synergy was associated with CDKI-73-mediated transcriptional inhibition of MCL1 and XIAP that was maintained when used in combination with fludarabine. Our data present a strong rationale for the development of cdk9 inhibitors such as CDKI-73 as anticancer therapeutics.
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MESH Headings
- Animals
- Antineoplastic Combined Chemotherapy Protocols/pharmacology
- Apoptosis
- Case-Control Studies
- Cyclin-Dependent Kinase 9/antagonists & inhibitors
- Cyclin-Dependent Kinase 9/genetics
- Drug Synergism
- HEK293 Cells
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/enzymology
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Mice
- Phosphorylation
- Prognosis
- Protein Kinase Inhibitors/administration & dosage
- Protein Kinase Inhibitors/pharmacology
- Pyrimidines/administration & dosage
- Pyrimidines/pharmacology
- Sulfonamides/administration & dosage
- Sulfonamides/pharmacology
- Transcription, Genetic/drug effects
- Vidarabine/administration & dosage
- Vidarabine/analogs & derivatives
- Vidarabine/pharmacology
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72
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Skilling KJ, Citossi F, Bradshaw TD, Ashford M, Kellam B, Marlow M. Insights into low molecular mass organic gelators: a focus on drug delivery and tissue engineering applications. SOFT MATTER 2014; 10:237-56. [PMID: 24651822 DOI: 10.1039/c3sm52244j] [Citation(s) in RCA: 254] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In recent years low molecular mass organic gelators (LMOGs) have gained increasing interest as an alternative biomaterial to polymer derived gels, with potential applications in drug delivery and tissue engineering. LMOGs are small organic molecules which self-assemble in water or organic solvents forming a 3D network that entraps the liquid phase resulting in gel formation. In this review, we report the classification of LMOGs into hydrogelators and gelators of organic solvents and we discuss the techniques commonly used to characterise the gels of these gelators with particular reference to specific applications of LMOGs in drug delivery and tissue engineering.
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73
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Leuner O, Havlik J, Budesinsky M, Vrkoslav V, Chu J, Bradshaw TD, Hummelova J, Miksatkova P, Lapcik O, Valterova I, Kokoska L. Cytotoxic constituents of Pachyrhizus tuberosus from Peruvian amazon. Nat Prod Commun 2013; 8:1423-1426. [PMID: 24354192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Abstract
Investigations into the chemical constituents of the seeds of the neglected tuber crop Pachyrhizus tuberosus (Leguminosae) resulted in the isolation of seven components: five rotenoids [12a-hydroxyerosone (1), 12a-hydroxydolineone (2), erosone (3), 12a-hydroxyrotenone (4) and rotenone (6)], a phenylfuranocoumarin [pachyrrhizine (5)] and an isoflavanone [neotenone (7)]. The compounds were isolated using several chromatography techniques and characterized and verified by NMR and HPLC/MS. The MTT assay was used to examine the selective cytotoxic effects of the methanolic P. tuberosus extract and isolated compounds in two human cancer cell lines [breast (MCF-7) and colorectal (HCT-116)] and in non-transformed human fibroblasts (MRC-5); IC50 values were calculated. The methanolic P. tuberosus extract displayed respectable cytotoxic effects against HCT-116 and MCF-7 cells with IC50 values of 7.3 and 6.3 microg/mL, respectively. Of the compounds, 6 exacted greatest cytotoxicity and selectivity towards the cancer cell lines tested, yielding IC50 values of 0.3 microg/mL against both MCF-7 and HCT-116 cells, and a 6-fold reduced activity against MRC-5 fibroblasts. Compound 4 also demonstrated cytotoxicity against MCF-7 and HCT-116 (1.1 and 1.8 microg/mL, respectively), and reduced cytotoxicity towards MRC-5 cells (7.5 mirog/mL). The results revealed from the in vitro cytotoxic MTT assay are worthy of further antitumor investigation.
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Leuner O, Havlik J, Budesinsky M, Vrkoslav V, Chu J, Bradshaw TD, Hummelova J, Miksatkova P, Lapcik O, Valterova I, Kokoska L. Cytotoxic Constituents of Pachyrhizus Tuberosus from Peruvian Amazon. Nat Prod Commun 2013. [DOI: 10.1177/1934578x1300801022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Investigations into the chemical constituents of the seeds of the neglected tuber crop Pachyrhizus tuberosus (Leguminosae) resulted in the isolation of seven components: five rotenoids [12a-hydroxyerosone (1), 12a-hydroxydolineone (2), erosone (3), 12a-hydroxyrotenone (4) and rotenone (6)], a phenylfuranocoumarin [pachyrrhizine (5)] and an isoflavanone [neotenone (7)]. The compounds were isolated using several chromatography techniques and characterized and verified by NMR and HPLC/MS. The MTT assay was used to examine the selective cytotoxic effects of the methanolic P. tuberosus extract and isolated compounds in two human cancer cell lines [breast (MCF-7) and colorectal (HCT-116)] and in non-transformed human fibroblasts (MRC-5); IC50 values were calculated. The methanolic P. tuberosus extract displayed respectable cytotoxic effects against HCT-116 and MCF-7 cells with IC50 values of 7.3 and 6.3 μg/mL, respectively. Of the compounds, 6 exacted greatest cytotoxicity and selectivity towards the cancer cell lines tested, yielding IC50 values of 0.3 μg/mL against both MCF-7 and HCT-116 cells, and a 6-fold reduced activity against MRC-5 fibroblasts. Compound 4 also demonstrated cytotoxicity against MCF-7 and HCT-116 (1.1 and 1.8 μg/mL, respectively), and reduced cytotoxicity towards MRC-5 cells (7.5 μg/mL). The results revealed from the in vitro cytotoxic MTT assay are worthy of further antitumor investigation.
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Tan BS, Kang O, Mai CW, Tiong KH, Khoo ASB, Pichika MR, Bradshaw TD, Leong CO. 6-Shogaol inhibits breast and colon cancer cell proliferation through activation of peroxisomal proliferator activated receptor γ (PPARγ). Cancer Lett 2013; 336:127-39. [PMID: 23612072 DOI: 10.1016/j.canlet.2013.04.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/04/2013] [Accepted: 04/15/2013] [Indexed: 02/06/2023]
Abstract
6-Shogaol has been shown to possess many antitumor properties including inhibition of cancer cell growth, inhibition of cancer metastasis, induction of apoptosis in cancer cells and induction of cancer cell differentiation. Despite its prominent antitumor effects, the direct molecular target of 6-shogaol has remained elusive. To identify the direct targets of 6-shogaol, a comprehensive antitumor profile of 6-shogaol (NSC752389) was tested in the NCI-60 cell line in an in vitro screen. The results show that 6-shogaol is COMPARE negative suggesting that it functions via a mechanism of action distinct from existing classes of therapeutic agents. Further analysis using microarray gene profiling and Connectivity Map analysis showed that MCF-7 cells treated with 6-shogaol display gene expression signatures characteristic of peroxisome proliferator activated receptor γ (PPARγ) agonists, suggesting that 6-shogaol may activate the PPARγ signaling pathway for its antitumor effects. Indeed, treatment of MCF-7 and HT29 cells with 6-shogaol induced PPARγ transcriptional activity, suppressed NFκB activity, and induced apoptosis in breast and colon cancer cells in a PPARγ-dependent manner. Furthermore, 6-shogaol is capable of binding to PPARγ with a binding affinity comparable to 15-delta prostaglandin J2, a natural ligand for PPARγ. Together, our findings suggest that the antitumor effects of 6-shogaol are mediated through activation of PPARγ and imply that activation of PPARγ might be beneficial for breast and colon cancer treatment.
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