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Future cancer treatment regimes may involve novel drug combinations aimed at targeting different pathways involved in tumour proliferation and survival. Understanding the mechanisms involved in such combinations and identifying the optimum schedule/sequence will be key to guiding clinical development. The Aurora kinases play a critical role in mitosis and have been suggested as promising targets for therapy due to their frequent over expression in a variety of tumours. AZD1152 is a selective Aurora B kinase inhibitor, with a novel anti-tumour mechanism of action, inducing endoreduplication, apoptosis and inhibition of cytokinesis. The MAPK signaling pathway is implicated in uncontrolled cell proliferation and cell survival in many cancers. AZD6244 (ARRY-142886), a selective, ATP non-competitive inhibitor of MEK1/2, has demonstrated G1 arrest and anti-tumour activity in a range of preclinical models. In the present study, we dosed AZD1152 and AZD6244 in combination to nude mice bearing human NSCLC tumour (Calu-6) xenografts. Pharmacodynamic analysis of Calu-6 xenografts treated with either AZD1152 or AZD6244 as monotherapies (MonTx) indicated downstream biomarker effects in accordance with their targets (for e.g. suppression of phosphorylation of histone H3 and ERK, respectively). When the same doses of AZD1152 (150mg/Kg/day s.c. for 2 days via osmotic minipumps) or AZD6244 (25mg/kg/BID p.o.) were dosed in a chronic disease setting, both drugs significantly suppressed Calu-6 tumour growth (versus respective vehicle groups, p → AZD6244 proved superior to both MonTx arms in terms of apoptosis induction and tumour growth inhibition. These data indicate a promising therapeutic strategy for combining AZD1152 and AZD6244, and suggest that the sequence of drug administration may be critical when combining these inhibitors. Both AZD1152 and AZD6244 are currently in clinical trials. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4434.

Cediranib (RECENTIN™) is a highly potent vascular endothelial growth factor (VEGF) signaling inhibitor of all three VEGF receptors that is suitable for once-daily oral dosing. Cediranib is currently in Phase III development in first-line colorectal cancer and recurrent glioblastoma. Work is ongoing to determine its potential utility in a range of other tumors including lung cancer. The aim of these preclinical studies was to examine the effect of combining cediranib with the following mechanistically distinct antitumor therapies: saracatinib (AZD0530; Src inhibitor), AZD6244 (MEK 1/2 inhibitor), 5-fluorouracil (5-FU), docetaxel, cisplatin, oxaliplatin, gemcitabine, pemetrexed and irinotecan. Details of the combination dosing schedules and xenograft models are provided in Table 1. Tumor cells grown in vitro were injected subcutaneously into the dorsal flank of female athymic mice (Swiss nu/nu genotype, ≥6 weeks of age). Mice were randomized into treatment groups (9-15 per group) once the mean tumor volume reached ∼200 mm3. When cediranib was dosed with parenterally administered agents, cediranib administration preceded that of the parenteral therapy by 2 hours. Antitumor effects were assessed by comparing mean tumor size at the end of the dosing period (12-28 days, depending on the model; Table 1) and significance was determined using the t-test (P100100 Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1372.

1. The metabolic clearance rate of arginine vasopressin was determined using a constant infusion technique in normal subjects and patients with chronic renal failure immediately before commencing dialysis. Endogenous arginine vasopressin was suppressed in all subjects before the infusion with a water load. 2. Plasma arginine vasopressin concentrations were determined using a sensitive and specific radioimmunoassay after Florisil extraction. The detection limit of the assay was 0.3 pmol/l, and intra- and inter-assay coefficients of variation at 2 pmol/l were 9.7% and 15.3%, respectively. 3. In normal subjects, the metabolic clearance rate was determined at two infusion rates producing steady-state concentrations of arginine vasopressin of 1.3 and 4.4 pmol/l. In the patients with renal failure, a single infusion rate was used, producing a steady-state concentration of 1.5 pmol/l. 4. At comparable plasma arginine vasopressin concentrations, metabolic clearance rate was significantly reduced in patients with renal failure (normal 1168 ± 235 ml/min versus renal failure 584 ± 169 ml/min; means ± sd; P 5. Free water clearance was significantly reduced in normal subjects during the arginine vasopressin infusion from 8.19 ± 2.61 to −1.41 ± 0.51 ml/min (P 6. In normal subjects there was a small but significant fall in metabolic clearance rate at the higher steady-state arginine vasopressin concentration (1168 ± 235 ml/min at 1.3 pmol/l versus 1059 ± 269 ml/min at 4.4 pmol/l; P = 0.016). 7. Our results show that the metabolic clearance rate of arginine vasopressin is reduced by approximately 50% in severe chronic renal failure. This alone may account for the raised plasma concentrations of the hormone seen in this condition.

Erythrocyte sodium-lithium countertransport activity is increased in a subgroup of patients with essential hypertension but activity also rises temporarily during normal pregnancy. It is not known if the mechanism of raised activity is the same in both of these situations. Standard sodium-lithium countertransport activity and its kinetic characteristics (sodium affinity and maximum velocity) were measured in 15 women with a normal pregnancy. The mechanism of raised sodium-lithium countertransport activity was an increase in maximum velocity. There was no change in sodium affinity. This contrasts with essential hypertension where the mechanism is increased sodium affinity. Sodium-lithium countertransport activity was also measured in 14 primigravidae whose pregnancies were complicated by hypertension, and mean activity was not significantly higher than in normal pregnancy. However, six women had increased sodium affinity suggestive of essential hypertension and a different underlying mechanism of hypertension to those with normal sodium affinity. Prospective measurement of sodium-lithium countertransport kinetics may lead to a better understanding of the pathophysiology of hypertension in pregnancy.

1. Young and mature erythrocytes from 15 normal subjects were used to compare the sodium pump rate constant measured in whole blood with the more definitive sodium affinity constant and maximum velocity of the sodium pump measured in artificial media using sodium-loaded cells. 2. Similar values were obtained from both erythrocyte fractions for the sodium affinity constant and maximum velocity and also by using two different plots. The median error in the estimate of individual sodium affinity constants and maximum velocities from regression analysis was about 20% and the precision was not improved by combining the data points for the two erythrocyte fractions. 3. The rate constant in whole blood was closely related to the sodium affinity constant and maximum velocity of the sodium pump (r = 0.75), suggesting that it was a reasonable overall assessment of available sodium pump activity. 4. Differences in the rate constant between subjects were due to differences in both the maximum velocity and sodium affinity constant of the sodium pump so that the rate constant could not be used as a guide to the underlying sodium pump physiology.

1. Sodium-lithium countertransport activity in a standard assay, its sodium affinity constant and maximum velocity were measured in erythrocytes from normal subjects and from essential hypertensive patients with and without a family history of hypertension. 2. In normal subjects the sodium concentration used in the standard assay was similar to the sodium affinity constant so that the activity measured in this assay was less than the maximum velocity. 3. In patients with essential hypertension and a positive family history, 33% had a sodium-lithium countertransport activity greater than the upper limit of the normal control range (0.4 mmol of Li+ h−1 l−1 of cells). 4. The reason for the raised sodium-lithium countertransport activity was an increased sodium affinity (lower sodium affinity constant) at the outside ion-binding site. 5. Of the patients with essential hypertension and a positive family history but sodium-lithium countertransport activity within the normal range in the standard assay, 30% also had a low sodium affinity constant. 6. A low sodium affinity constant at the outside site of the sodium-lithium countertransporter may be a more specific indicator for a group of patients with inherited hypertension than the standard sodium-lithium countertransport activity assay.

AZD1152 is a specific Aurora kinase inhibitor with selectivity for Aurora B kinase, designed to target cell division in proliferating tumour cells. It has been shown in model systems that inhibition of Aurora B kinase with AZD1152 reduces histone H3 phosphorylation (phH3) and inhibits cytokinesis, thus inducing cellular multi-nucleation and polyploidy, leading to apoptosis and cell death. Here, we present results of preliminary studies on the in vivo action of AZD1152 on the growth and development of both a human acute myeloid leukaemia (AML) cell line (HL-60) and primary AML samples in the NOD/SCID xeno-transplantation model. Two weeks of AZD1152 at 25 mg/kg/day is well tolerated in NOD/SCID mice. HL-60 cells were injected iv into sub-lethally irradiated NOD/SCID mice (n=24) and allowed to engraft in the bone marrow. Three weeks later, when malignant cell growth was well established in the bone marrow, mice were split into treatment groups. Either vehicle (n=12) or AZD1152 (25 mg/kg/day via minipump, n=12) was administered for 7 days. One AZD1152-treated group was sacrificed immediately post-treatment (n=9) and another was left for a further 2 weeks before bone marrow analysis for HL-60 cell content (defined by human CD45+/CD33+/CD19− expression). The mean percentage HL-60 cell content in the marrow of untreated mice was 64.5 ± 19.0 (range 14.0–86.6, n=11), whereas in mice that had received AZD1152 and were sacrificed at the end of dosing period, the mean percentage was 0.29 ± 0.74 (range 0–2.26, n=9; p Similar experiments were performed with two primary AML samples. AML-1 is from a patient with French-American-British (FAB)-type M1 AML and AML-2 is from a FAB-type M2 AML patient. Ten million cells from both AML samples were injected into NOD/SCID mice (n=12 for AML-1; n=6 for AML-2). Ten weeks later, mice were split into treatment groups and dosed with either control vehicle or 25 mg/kg/day of AZD1152 via minipumps for 7 days. All mice were sacrificed after 1 week of treatment in these initial experiments. The mean percentage engraftment in untreated mice was 59.7 ± 36.0 (range 6.2–84.0, n=4) for AML-1 and 21.8 ± 22.5 (range 5.9–37.7, n=2) for AML-2. Whereas, in mice that had received 25 mg/kg/day of AZD1152 for 7 days, the percentage of engraftment was 1.8 ± 1.7 (range 0.38–4.53, n=5; p These data indicate that AZD1152 has a profound effect on the engraftment of human AML cell lines and primary AML samples in an in vivo model. Furthermore, initial results may indicate a long-term effect of AZD1152 treatment in vivo. AZD1152 is currently undergoing Phase I clinical trials in AML patients.

To determine whether there are familial and genetic aspects of sodium-lithium countertransport activity in red cells in diabetic nephropathy.Case-control study.Teaching hospital diabetic clinic.40 Patients with insulin dependent diabetes, both of whose parents were alive: 20 with persistent proteinuria and 20 with normal albumin excretion matched for age, duration of diabetes, and body mass index. All 80 parents.Sodium-lithium countertransport activity in red cells and arterial blood pressure.Sodium-lithium countertransport activity in red cells was higher in the patients with proteinuria than in the patients with normoalbuminuria (mean (95% confidence interval) 0.47 (0.39 to 0.54) v 0.33 (0.28 to 0.38) mmol/l red cells/h respectively, p = 0.0036; mean difference 0.14 (0.04 to 0.22)). The mean countertransport activity for the two parents of each patient was calculated, and from this the mean value for each group of parents was calculated; the value was higher in the parents of the patients with proteinuria than in the parents of the patients with normoalbuminuria (0.40 (0.32 to 0.48) v 0.30 (0.26 to 0.33) mmol/l red cells/h respectively, p = 0.016; 0.10 (0.02 to 0.19)). Twenty-eight of the parents of the patients with proteinuria compared with 12 of the parents of the patients with normoalbuminuria had a countertransport activity that was above the median value in all 80 parents (p less than 0.001). Mean arterial blood pressure in the parents of the patients with proteinuria was related to that of their offspring (r = 0.46; p less than 0.01). There was a positive correlation between the sodium-lithium countertransport activity in red cells in the parents and their offspring when all parents and patients were considered (r = 0.37; p less than 0.001).Increased sodium-lithium countertransport activity in red cells in the parents of diabetic patients with nephropathy provides further evidence that familial, and possibly genetic, factors related to a predisposition to arterial hypertension have a role in the susceptibility of diabetic renal disease.

Objective To establish the changes in erythrocyte sodium lithium countertransport (SLC) with advancing normal pregnancy and to determine if these changes were different in pregnancy induced hypertension (PIH). The changes in both groups were assessed in relation to haemodynamic changes. Design SLC, mean arterial pressure (MAP), cardiac output (CO) and total peripheral vascular resistance (TPVR) were determined serially during normal pregnancy and cross-sectionally in PIH. Women were studied again 20 weeks after delivery where possible. Setting Routine antenatal clinic and antenatal ward of a regional reference centre. Subjects Fifty-one normal primigravid women were studied serially and 41 primigravid women with PIH were studied at time of diagnosis. Results During normal pregnancy SLC (mmol Li/h/l cells) increased from a nonpregnant value of 0.24 ± 0.02 (mean ± SEM) to 0.32 ± 0.02 at 14 weeks, and 0.37 ± 0.02 at 20 weeks gestation. This was maintained until 38 weeks (0.40 ± 0.02). The increase until 20 weeks occurred at the time of greatest change in CO (5.10 ± 0.18 to 6.79 ± 0.20 l/min) and TPVR (1327 ± 58 to 969 ± 33 dyn/s/cm−5). The decrease in TPVR with a rise in SLC is opposite to the relation reported in essential hypertension so that a functional relation is unlikely. However, the changes within pregnancy were positively correlated (r = 0.43, P