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6 Abstracts / Toxico

hich subsequently decreased to a steady excretion rate; a resultlso reflected in the plasma.

These data indicate that a combination of NMR and gel-basedethodologies provides a comprehensive analytical platform toonitor the kinetics and metabolic fate of both the PEG and pro-

ein components of PEGylated biopharmaceuticals, as well as theolecular integrity of the conjugate. These assays have potential

pplication for PK studies of PEGylated agents in man.

eference

rmstrong, J., 2009. PEGylated Protein Drugs: Basic Science and Clinical Applica-tions, 147–168.

arris, J., Chess, B., 2003. Nature Reviews: Drug Discovery 2, 214–221.ebster, R., Didier, E., Harris, P., Siegel, N., Stadler, J., Tilbury, L., Smith, D., 2007.

Drug Metab. Dispos. 35, 9–16.

oi:10.1016/j.tox.2011.09.064

057

ssessing the cytotoxic profile of novel endoperoxide deriva-ives

ames W. Firman 1,∗, Marion MacFarlane 2, B. Kevin Park 1, Amy E.ercer 1

MRC Centre for Safety Science, University of Liverpool, L69 3GE,nited KingdomMRC Toxicology Unit, University of Leicester, LE1 9HN, United King-om-mail address: j.w.firman@student.liverpool.ac.uk (J.W. Firman).

Derived from the natural product artemisinin, endoperoxidentimalarials are employed as frontline treatment against resistantlasmodium falciparum strains. Although generally well-toleratedn man, evidence of neuro and embryotoxicity derived from ani-

al studies has led the WHO to recommend their contraindicationuring the first trimester of pregnancy. Central to their antipar-sitic and toxicological mechanisms of action is the formation ofarbon-centred radicals through Fe(II)-dependent activation of thendoperoxide bridge (Haynes and Vonwiller, 1996). The cellularoute through which toxicity is mediated has remained largelyndefined, hindering the development of safer drug analogues.tudies within the group have established that the induction ofitochondrial dysfunction and reactive oxygen species forma-

ion precedes cell death through an apoptotic mechanism, withaem-containing proteins highlighted as essential targets for rad-

cal alkylation (Mercer et al., 2011).The incorporation of the endoperoxide pharmacophore into

ynthetic molecular frameworks has allowed for the develop-ent of novel drug classes possessing favourable antiparasitic and

ytotoxic properties relative to traditional artemisinin-based com-ounds such as DHA (Jefford, 2007). We have employed human

eukaemia (HL-60) cell lines in order to assess the cytotoxic profiles

f representative trioxane and tetraoxanes FBEG-100 and RKA-182,xamining the relationship between levels of cell death, mitochon-rial dysfunction and the induction of apoptosis. Through use of theTT assay, activity against cells has been quantified. Flow cytomet-

able 14 h, expressed as mean ± SD, n = 3.

Compound IC50 (�M) Concentration (�M

FBEG-100 23.57 ± 1.57 110

RKA-182 5.07 ± 0.72 110

DHA 0.39 ± 0.11 110

90 (2011) 1–46

ric analysis employing TMRE has been utilised in order to determinelevels of mitochondrial depolarisation, with the emergence of anapoptotic cell population visualised using PI staining (Table 1).

It is demonstrated that, across the compounds investigated,tetraoxanes exhibit greater levels of toxicity than trioxanes. Bothare shown to induce concentration-dependent depolarisation ofthe mitochondrial membrane, and initiate cell death via an apop-totic route. Combined with their enhanced antiparasitic activities,they offer an improved benefit-to-risk ratio in relation to theartemisinin-derived DHA.

Reference

Haynes, R.K., Vonwiller, S.C., 1996. Tett. Lett. 37 (2), 253–256.Jefford, C.W., 2007. Drug Disc. Today 12 (11–12), 487–495.Mercer, A.E., et al., 2011. J. Biol. Chem. 286 (2), 987–996.

doi:10.1016/j.tox.2011.09.065

P058

Urinary biomarkers of renal injury in the hexachloro-1:3-butadiene treated male Hanover Wistar rat; a dose-responsestudy at low dose levels

Ines Pereira 1,∗, Aubrey Swain 2, John Turton 3, Cheryl L.Scudamore 4, David Maguire 4, Rosemary Smyth 1, Sofia Freitas 1,Michael Munday 1, Clare Stamp 2, Mitul Gandhi 2, Surjit Sondh 2,Holly Ashall 2, Ian Francis 2, Jennifer Woodfine 2, Malcolm York 2

1 School of Pharmacy, London WC1N 1AX, United Kingdom2 GlaxoSmithKline, Ware, SG12 0DP, United Kingdom3 University College London, W1W 7EJ, United Kingdom4 Royal Veterinary College, AL9 7TA, United KingdomE-mail address: ines.pereira@live.pharmacy.ac.uk (I. Pereira).

Introduction: Most traditional biomarkers for renal injury arenot sensitive enough to detect early lesions in preclinical studies.Recent advances in toxicogenomics have identified novel urinaryrenal biomarkers which may have useful potential (Thukral et al.,2005). These include kidney injury molecule-1 (KIM-1), lipocalin-2,alpha-glutathione S-transferase (�GST) and osteopontin. The mainfocus of the present work was to compare traditional and newrenal biomarkers and assess their sensitivity when acute injury isinduced using hexachloro-1:3-butadiene (HCBD).

Methods: 48 male Hanover Wistar rats (weight 223 g; age, 7-8weeks) were allocated into 8 dose level groups (n = 6) and dosed IPwith vehicle (controls) or HCBD at 5, 10, 15, 20, 30, 45 and 90 mg/kg,placed in metabolism cages and 24 h urine samples collected. Onremoval and autopsy, kidney samples were taken into fixative andstained with haematoxylin and eosin. Blood was taken for plasmapreparation. Kidney and liver samples were taken for gene expres-sion analysis. Plasma and urine were assayed on the Siemens Advia1650 Clinical Chemistry System (Siemens Healthcare Diagnostics).

Urine was also assayed for renal biomarkers on the Sector Imager6000 (Meso Scale Discovery).

Results and conclusions: Histological changes consistent withinjury to the S3 segment of the nephron were not evident at 5 mg/kg

) % Depolarised cells % Sub G0/G1

10.86 ± 1.54 14.54 ± 1.4731.63 ± 16.22 17.42 ± 5.3611.89 ± 1.74 12.70 ± 4.5244.64 ± 7.06 49.98 ± 14.8252.21 ± 4.73 66.80 ± 3.7385.86 ± 5.72 72.11 ± 23.74

Abstracts / Toxicology 2

Table 1Lowest dose level of hexachloro-1:3-butadiene (HCBD) at which a statistically sig-nificant increase in urinary/plasma biomarker level was identified.a

Biomarker HCBD (mg/kg)

Beta-hydroxybutyrate 10Kidney injury molecule-1 10Alpha-glutathione S-transferase 10Glutathione S-transferase Yb1 10Albumin 15Total protein 90Glucose 90Acetoacetate 90Plasma creatinine 90Plasma urea 90Clusterin 90Lipocalin-2 –Osteopontin –

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a All markers were assayed in urine, except for plasma creatinine and urea; ani-als were dosed at 0 (control), 5, 10, 15, 20, 30, 45 and 90 mg/kg HCBD.

CBD but at 10 mg/kg mild degeneration was seen. There was thendose-related increase in severity and at 90 mg/kg degenerationas marked/very marked. Table 1 gives the lowest dose levels

f HCBD at which statistically significant increases (p = <0.01) iniomarker levels in urine/plasma were identified. Urinary beta-ydroxybutyrate (BHBT) showed a significant increase at 10 mg/kg,nd urinary KIM-1, �-GST and GST Yb1demonstrated increasesn output at 10 mg/kg. Urinary acetoacetate (ACAT), clusterin,lasma creatinine and plasma urea, showed significant increasest 90 mg/kg. Levels of urinary osteopontin and lipocalin-2 were notncreased at any HCBD dose level. With biomarker levels expresseds fold increase over control, the greatest increases at 90 mg/kgere albumin, 131; ACAT, 574; �-GST, 649 times. The origin of theose-related increases in BHBT and ACAT are unclear.

Hepatic and renal gene expression analysis indicated exposurend metabolic response in the HCBD-treated animals. It is con-luded that the newly proposed urinary biomarkers KIM-1, �-GSTnd albumin showed sensitive responses following segment 3 kid-ey injury in the HCBD-treated Hanover Wistar rat.

eference

hukral, S.K., et al., 2005. Toxicol. Pathol. 33, 343–355.

oi:10.1016/j.tox.2011.09.066

ig. 1. Left: Proliferation and PSA expression at 120 h. Left axis and open columns are PSA enly shown for 120 h. Mean ± SEM, n = 3. Statistical analysis by 2-way ANOVA (comparisoight: Expression of miR-221 at 120 h. N = 4.

90 (2011) 1–46 37

P059

Using miRNA ‘fingerprints’ to investigate androgen-mediatedphenotypic change

Corrinne V. Segal a,∗, Christopher J. Powell b, Nigel J. Gooderham a

a Biomolecular Medicine, Imperial College London, United Kingdomb GlaxoSmithKline, Ware, United KingdomE-mail address: c.segal08@imperial.ac.uk (C.V. Segal).

Activation of the androgen receptor (AR) results in phenotypicchange in androgen-responsive cells; for example, in the humanprostate carcinoma cell line LNCaP, androgens can induce cell pro-liferation (Horoszewicz et al., 1983). Factors controlling the range ofphenotypic responses to androgens are only partially understood,but include both transcriptional and post-transcriptional mecha-nisms. One such mechanism that appears to offer wide ranging,yet highly selective control, is microRNA(miRNA)-mediated post-transcriptional regulation. Predominantly negative regulators ofgene expression, miRNA are short non-coding RNA that are ableto suppress translation or induce degradation of their target mRNAtranscripts leading to decreased protein expression (Nilsen, 2007).

In the present study, we assessed the temporal influence of ARagonists mibolerone and 5�-dihydrotestosterone and antagonistbicalutamide on the miRNA profile of LNCaP. Phenotypic responseto exposure was assessed as an alteration of proliferative abil-ity (measured as fluorescence) and expression of prostate-specificantigen (PSA). The expression profile of 866 miRNAs was assessedusing Agilent’s miRNA microarray v.3 with data analysis conductedin ‘R’ using AgiMicroRna, ComBat and Limma. Validation of selectedmiRNA was achieved using qRT-PCR and the ��CT method of anal-ysis.

As expected, the agonists induced proliferation and PSA expres-sion, compared to vehicle control, whilst the antagonist itself hadminimal effect (Fig. 1: left). Microarray analysis identified 16 miR-NAs that were altered in a compound-specific and temporal manner(with an FDR adjusted p-value < 0.05 and fold-change > 1.5). Forexample, miR-221 was down-regulated at 120 h in mibolerone-treated cells compared to the time-matched vehicle control.Subsequent Real-Time RT-PCR of miR-221 confirmed the change

observed by microarray (Fig. 1: right).

These data describe an androgen-mediated miRNA fingerprintthat is compound and temporally dependent. We are currently

xpression, right axis and striped columns are proliferative response. For clarity, datan between treatment and time-matched control; ***P < 0.001, **P < 0.01, *P < 0.05).