Clinical and Experimental Pharmacology GroupCEPhttp://hdl.handle.net/10541/558032024-03-13T11:34:29Z2024-03-13T11:34:29ZReactivating HIF prolyl hydroxylases under hypoxia results in metabolic catastrophe and cell death.Tennant, D AFrezza, CMacKenzie, E DNguyen, Q DZheng, LSelak, M ARoberts, Darren LDive, CarolineWatson, D GAboagye, E OGottlieb, Ehttp://hdl.handle.net/10541/914882019-08-30T13:24:58Z2009-11-12T00:00:00ZReactivating HIF prolyl hydroxylases under hypoxia results in metabolic catastrophe and cell death.
Tennant, D A; Frezza, C; MacKenzie, E D; Nguyen, Q D; Zheng, L; Selak, M A; Roberts, Darren L; Dive, Caroline; Watson, D G; Aboagye, E O; Gottlieb, E
Cells exposed to low-oxygen conditions (hypoxia) alter their metabolism to survive. This response, although vital during development and high-altitude survival, is now known to be a major factor in the selection of cells with a transformed metabolic phenotype during tumorigenesis. It is thought that hypoxia-selected cells have increased invasive capacity and resistance to both chemo- and radiotherapies, and therefore represent an attractive target for antitumor therapy. Hypoxia inducible factors (HIFs) are responsible for the majority of gene expression changes under hypoxia, and are themselves controlled by the oxygen-sensing HIF prolyl hydroxylases (PHDs). It was previously shown that mutations in succinate dehydrogenase lead to the inactivation PHDs under normoxic conditions, which can be overcome by treatment with alpha-ketoglutarate derivatives. Given that solid tumors contain large regions of hypoxia, the reactivation of PHDs in these conditions could induce metabolic catastrophe and therefore prove an effective antitumor therapy. In this report we demonstrate that derivatized alpha-ketoglutarate can be used as a strategy for maintaining PHD activity under hypoxia. By increasing intracellular alpha-ketoglutarate and activating PHDs we trigger PHD-dependent reversal of HIF1 activation, and PHD-dependent hypoxic cell death. We also show that derivatized alpha-ketoglutarate can permeate multiple layers of cells, reducing HIF1alpha levels and its target genes in vivo.
2009-11-12T00:00:00ZDetection of BRAF mutations in the tumour and serum of patients enrolled in the AZD6244 (ARRY-142886) advanced melanoma phase II study.Board, Ruth EEllison, GOrr, M C MKemsley, K RMcWalter, GBlockley, L YDearden, S PMorris, CRanson, Malcolm RCantarini, M VDive, CarolineHughes, Ahttp://hdl.handle.net/10541/914062019-08-30T13:24:59Z2009-11-17T00:00:00ZDetection of BRAF mutations in the tumour and serum of patients enrolled in the AZD6244 (ARRY-142886) advanced melanoma phase II study.
Board, Ruth E; Ellison, G; Orr, M C M; Kemsley, K R; McWalter, G; Blockley, L Y; Dearden, S P; Morris, C; Ranson, Malcolm R; Cantarini, M V; Dive, Caroline; Hughes, A
BACKGROUND: This study investigated the potential clinical utility of circulating free DNA (cfDNA) as a source of BRAF mutation detection in patients enrolled into a phase II study of AZD6244, a specific MEK1/2 inhibitor, in patients with advanced melanoma. METHODS: BRAF mutations were detected using Amplification Refractory Mutation System allele-specific PCR. BRAF mutation status was assessed in serum-derived cfDNA from 126 patients enrolled into the study and from 94 matched tumour samples. RESULTS: Of 94 tumour samples, 45 (47.9%) were found to be BRAF mutation positive (BRAF+). Serum-derived cfDNA was BRAF+ in 33 of 126 (26.2%) samples, including in five samples for which tumour data were unavailable. Of BRAF+ tumours, 25 of 45 (55.6%) were BRAF+ in cfDNA. In three cases in which the tumour was negative, cfDNA was BRAF+. Progression-free survival (PFS) of patients with BRAF+ tumour and cfDNA was not significantly different compared with tumour BRAF+ but cfDNA BRAF-negative patients, indicating that cfDNA BRAF detection is not associated with poorer prognosis on PFS in stage III/IV advanced melanoma. CONCLUSIONS: These data demonstrate the feasibility of BRAF mutation detection in cfDNA of patients with advanced melanoma. Future studies should aim to incorporate BRAF mutation testing in cfDNA to further validate this biomarker for patient selection.
2009-11-17T00:00:00ZA small molecule inhibitor of XIAP induces apoptosis and synergises with vinorelbine and cisplatin in NSCLC.Dean, Emma JWard, Timothy HPinilla, CHoughten, RWelsh, KMakin, Guy W JRanson, Malcolm RDive, Carolinehttp://hdl.handle.net/10541/877002019-08-30T13:16:10Z2009-11-10T00:00:00ZA small molecule inhibitor of XIAP induces apoptosis and synergises with vinorelbine and cisplatin in NSCLC.
Dean, Emma J; Ward, Timothy H; Pinilla, C; Houghten, R; Welsh, K; Makin, Guy W J; Ranson, Malcolm R; Dive, Caroline
Background:Evasion of apoptosis contributes to the pathogenesis of solid tumours including non-small cell lung cancer (NSCLC). Malignant cells resist apoptosis through over-expression of inhibitor of apoptosis proteins (IAPs), such as X-linked IAP (XIAP).Methods:A phenylurea-based small molecule inhibitor of XIAP, XIAP antagonist compound (XAC) 1396-11, was investigated preclincally to determine its ability to sensitise to clinically relevant cytotoxics, potentially allowing dose reduction while maintaining therapeutic efficacy.Results:XIAP protein expression was detected in six NSCLC cell lines examined. The cytotoxicity of XAC 1396-11 against cultured NSCLC cell lines in vitro was concentration- and time-dependent in both short-term and clonogenic assays. XAC 1396-11-induced apoptosis was confirmed by PARP cleavage and characteristic nuclear morphology. XAC 1396-11 synergised with vinorelbine+/-cisplatin in H460 and A549 NSCLC cells. The mechanism of synergy was enhanced apoptosis, shown by increased cleavage of caspase-3 and PARP and by the reversal of synergy by a pan-caspase inhibitor. Synergy between XAC 1396-11 and vinorelbine was augmented by optimising drug scheduling with superior effects when XAC 1396-11 was administered before vinorelbine.Conclusion:These preclinical data suggest that XIAP inhibition in combination with vinorelbine holds potential as a therapeutic strategy in NSCLC.British Journal of Cancer advance online publication, 10 November 2009; doi:10.1038/sj.bjc.6605418 www.bjcancer.com.
2009-11-10T00:00:00ZContribution of HIF-1 and drug penetrance to oxaliplatin resistance in hypoxic colorectal cancer cells.Roberts, Darren LWilliams, Kaye JCowen, Rachel LBarathova, MEustace, A JBrittain-Dissont, STilby, Michael JPearson, D GrahamOttley, Christopher JStratford, Ian JDive, Carolinehttp://hdl.handle.net/10541/875592019-08-30T13:18:52Z2009-10-20T00:00:00ZContribution of HIF-1 and drug penetrance to oxaliplatin resistance in hypoxic colorectal cancer cells.
Roberts, Darren L; Williams, Kaye J; Cowen, Rachel L; Barathova, M; Eustace, A J; Brittain-Dissont, S; Tilby, Michael J; Pearson, D Graham; Ottley, Christopher J; Stratford, Ian J; Dive, Caroline
BACKGROUND: Hypoxia is as an indicator of poor treatment outcome. Consistently, hypoxic HCT116 colorectal cancer cells are resistant to oxaliplatin, although the mechanistic basis is unclear. This study sought to investigate the relative contribution of HIF-1 (hypoxia-inducible factor-1)-mediated gene expression and drug penetrance to oxaliplatin resistance using three-dimensional spheroids. METHODS: Hypoxia-inducible factor-1alpha function was suppressed by the stable expression of a dominant-negative form in HCT116 cells (DN). Cells were drug exposed as monolayer or multicellular spheroid cultures. Cells residing at differing oxygenation status were isolated from Hoechst 33342-treated spheroids using flow cytometry. Sub-populations were subjected to clonogenic survival assays and to Inductively-Coupled Plasma Mass Spectroscopy to determine oxaliplatin uptake. RESULTS: In spheroids, a sensitivity gradient (hypoxic
2009-10-20T00:00:00Z