Dataset for reprogramming the transcriptional response to hypoxia with a chromosomally encoded cyclic peptide HIF-1 inhibitor.

Dataset from: Mistry, Ishna and Tavassoli, Ali (2016) Reprogramming the transcriptional response to hypoxia with a chromosomally encoded cyclic peptide HIF-1 inhibitor. ACS Synthetic Biology (doi: 10.1021/acssynbio.6b00219). Array data from TaqMan human hypoxia array analysis of the engineered cell line +/- dox and +/- HIF-2a siRNA.</span

Probing the epigenetic regulation of HIF-1α transcription in developing tissue

HIF-1 is the master regulator of cellular hypoxia response; the oxygen sensitive HIF-1α subunit transactivates its own expression in hypoxia via a hypoxia response element (HRE) in the promoter of the HIF-1α gene. This transactivation loop significantly contributes to the build up of HIF-1α at the onset of hypoxia, with the binding of HIF-1 to the HIF-1α promoter being dependent on the epigenetic status of a CpG dinucleotide in the upstream HRE. Given the central role played by HIF-1 in tissue development, we sought to probe the epigenetic status of the HIF-1α HRE and that of its downstream target EPO in embryonic tissue. Our data shows that the CpG dinucleotide in HIF-1α HRE is unmethylated in several embryonic tissue samples, suggesting that transactivation of HIF-1α plays a significant role in HIF-1 mediated hypoxia response during development

Dataset for: Hypoxia drives the assembly of the multi-enzyme purinosome complex

Dataset supporting the paper: Doigneaux, C., Pedley, A., Mistry, I. N., Papayova, M., Benkovic, S., &amp; Tavassoli, A. (Accepted/In press). Hypoxia drives the assembly of the multi-enzyme purinosome complex. The Journal of Biological Chemistry. DOI:10.1074/jbc.RA119.012175</span

Hypoxia drives the assembly of the multi-enzyme purinosome complex

The purinosome is a dynamic metabolic complex composed of enzymes responsible for de novo purine biosynthesis, whose formation has been associated with elevated purine demand. However, the physiological conditions that govern purinosome formation in cells remain unknown. Here, we report that purinosome formation is up-regulated in cells in response to a low-oxygen microenvironment (hypoxia). We demonstrate that increased purinosome assembly in hypoxic human cells requires the activation of hypoxia inducible factor 1 (HIF-1) and not HIF-2. Hypoxia-driven purinosome assembly was inhibited in cells lacking 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (ATIC), a single enzyme in de novo purine biosynthesis, and in cells treated with a small molecule inhibitor of ATIC homodimerization. However, despite the increase in purinosome assembly in hypoxia, we observed no associated increase in de novo purine biosynthesis was observed in cells. Our results indicate that this was likely due to a reduction in mitochondrial one-carbon metabolism, resulting in reduced mitochondrion-derived one-carbon units needed for de novo purine biosynthesis. The findings of our study further clarify and deepen our understanding of purinosome formation by revealing that this process does not solely depend on cellular purine demand

Hypoxia-Activated Pro-Drugs of the KDAC Inhibitor Vorinostat (SAHA)

Hypoxia (lower than normal oxygen) is a characteristic of most solid tumours that results in poor cancer patient prognosis. The difference in cellular environment between normoxia (21% oxygen) or physoxia (4.5-7% oxygen) and hypoxia (</div

Development and pre-clinical testing of a novel hypoxia-activated KDAC inhibitor

Tumor hypoxia is associated with therapy resistance and poor patient prognosis. Hypoxia-activated prodrugs, designed to selectively target hypoxic cells while sparing normal tissue, represent a promising treatment strategy. We report the pre-clinical efficacy of 1-methyl-2-nitroimidazole panobinostat (NI-Pano, CH-03), a novel bioreductive version of the clinically used lysine deacetylase inhibitor, panobinostat. NI-Pano was stable in normoxic (21% oxygen) conditions and underwent NADPH-CYP-mediated enzymatic bioreduction to release panobinostat in hypoxia (<0.1% oxygen). Treatment of cells grown in both 2D and 3D with NI-Pano increased acetylation of histone H3 at lysine 9, induced apoptosis and decreased clonogenic survival. Importantly, NI-Pano exhibited growth delay effects as a single agent in tumor xenografts. Pharmacokinetic analysis confirmed the presence of sub- micromolar concentrations of panobinostat in hypoxic mouse xenografts, but not in circulating plasma or kidneys. Together, our preclinical results provide a strong mechanistic rationale for the clinical development of NI-Pano for selective targeting of hypoxic tumors.<br /

Fluorescent transmembrane anion transporters: shedding light on anionophoric activity in cells

A series of fluorescent anion transporters consisting of a urea or thiourea group linked to a naphthalimide fluorophore have been synthesised and their anion transport properties studied. The compounds possess similar anion transport properties to (thio)urea-based anionophores that have previously been reported. Fluorescence studies in cells show all anionophores cross the plasma membrane and localise within the interior of cells. The most lipophilic, aromatic substituted transporters localise homogeneously throughout the cell and are toxic towards cancer cells with the highly fluorinated compound 6 being the most effective. The least lipophilic, alkyl substituted transporters localise in specific vesicles and are nontoxic to cells. This work provides new insight to the actions of anionophores in cells and may be useful in the design of novel antineoplastic agents.1122sciescopu

Fluorescent transmembrane anion transporters: shedding light on anionophoric activity in cells

A series of fluorescent anion transporters consisting of a urea or thiourea group linked to a naphthalimide fluorophore have been synthesised and their anion transport properties studied. The compounds possess similar anion transport properties of (thio)urea-based anionophores that have previously been reported. Fluorescence studies in cells show all anionophores cross the plasma membrane and localise within the interior of cells. The most lipophilic, aromatic substituted transporters localise homogeneously throughout the cell and are toxic towards cancer cells with the highly fluorinated compound 6 being the most effective. The least lipophilic, alkyl substituted transporters localise in specific vesicles and are non-toxic to cells. This work provides new insight to the actions of anionophores in cells and may be useful in the design of novel antineoplastic agents.<br/

Clinical Advances of Hypoxia-Activated Prodrugs in Combination With Radiation Therapy

With the increasing incidence of cancer worldwide, the need for specific, effective therapies is ever more urgent. One example of targeted cancer therapeutics is hypoxia-activated prodrugs (HAPs), also known as bioreductive prodrugs. These prodrugs are inactive in cells with normal oxygen levels but in hypoxic cells (with low oxygen levels) undergo chemical reduction to the active compound. Hypoxia is a common feature of solid tumors and is associated with a more aggressive phenotype and resistance to all modes of therapy. Therefore, the combination of radiotherapy and bioreductive drugs presents an attractive opportunity for synergistic effects, as the HAP targets the radiation resistant hypoxic cells. HAPs have typically been precursors of DNA damaging agents, but a new generation of molecularly targeted HAPs is emerging. By targeting proteins associated with tumorigenesis and survival, these compounds may result in greater selectivity over healthy tissue. We review the clinical progress of HAPs as adjuncts to radiotherapy, and conclude that the use of HAPs alongside radiation is vastly underexplored at the clinical level