Intratumoural expression of deoxycytidylate deaminase or ribonuceotide reductase subunit M1 expression are not related to survival in patients with resected pancreatic cancer given adjuvant chemotherapy.

BACKGROUND: Deoxycytidylate deaminase (DCTD) and ribonucleotide reductase subunit M1 (RRM1) are potential prognostic and predictive biomarkers for pyrimidine-based chemotherapy in pancreatic adenocarcinoma. METHODS: Immunohistochemical staining of DCTD and RRM1 was performed on tissue microarrays representing tumour samples from 303 patients in European Study Group for Pancreatic Cancer (ESPAC)-randomised adjuvant trials following pancreatic resection, 272 of whom had received gemcitabine or 5-fluorouracil with folinic acid in ESPAC-3(v2), and 31 patients from the combined ESPAC-3(v1) and ESPAC-1 post-operative pure observational groups. RESULTS: Neither log-rank testing on dichotomised strata or Cox proportional hazard regression showed any relationship of DCTD or RRM1 expression levels to survival overall or by treatment group. CONCLUSIONS: Expression of either DCTD or RRM1 was not prognostic or predictive in patients with pancreatic adenocarcinoma who had had post-operative chemotherapy with either gemcitabine or 5-fluorouracil with folinic acid.

Expression of dihydropyrimidine dehydrogenase (DPD) and hENT1 predicts survival in pancreatic cancer.

BACKGROUND: Dihydropyrimidine dehydrogenase (DPD) tumour expression may provide added value to human equilibrative nucleoside transporter-1 (hENT1) tumour expression in predicting survival following pyrimidine-based adjuvant chemotherapy. METHODS: DPD and hENT1 immunohistochemistry and scoring was completed on tumour cores from 238 patients with pancreatic cancer in the ESPAC-3(v2) trial, randomised to either postoperative gemcitabine or 5-fluorouracil/folinic acid (5FU/FA). RESULTS: DPD tumour expression was associated with reduced overall survival (hazard ratio, HR = 1.73 [95% confidence interval, CI = 1.21-2.49], p = 0.003). This was significant in the 5FU/FA arm (HR = 2.07 [95% CI = 1.22-3.53], p = 0.007), but not in the gemcitabine arm (HR = 1.47 [0.91-3.37], p = 0.119). High hENT1 tumour expression was associated with increased survival in gemcitabine treated (HR = 0.56 [0.38-0.82], p = 0.003) but not in 5FU/FA treated patients (HR = 1.19 [0.80-1.78], p = 0.390). In patients with low hENT1 tumour expression, high DPD tumour expression was associated with a worse median [95% CI] survival in the 5FU/FA arm (9.7 [5.3-30.4] vs 29.2 [19.5-41.9] months, p = 0.002) but not in the gemcitabine arm (14.0 [9.1-15.7] vs. 18.0 [7.6-15.3] months, p = 1.000). The interaction of treatment arm and DPD expression was not significant (p = 0.303), but the interaction of treatment arm and hENT1 expression was (p = 0.009). CONCLUSION: DPD tumour expression was a negative prognostic biomarker. Together with tumour expression of hENT1, DPD tumour expression defined patient subgroups that might benefit from either postoperative 5FU/FA or gemcitabine.

In vitro and in vivo characterization of PF-04418948, a novel, potent and selective prostaglandin EP2 receptor antagonist.

BACKGROUND AND PURPOSE: Studies of the role of the prostaglandin EP(2) receptor) have been limited by the availability of potent and selective antagonist tools. Here we describe the in vitro/in vivo pharmacological characterization of a novel EP(2) receptor antagonist, PF-04418948 (1-(4-fluorobenzoyl)-3-{[(6-methoxy-2-naphthyl)oxy]methyl} azetidine-3-carboxylic acid). EXPERIMENTAL APPROACH: Functional antagonist potency was assessed in cell-based systems expressing human EP(2) receptors and native tissue preparations from human, dog and mouse. The selectivity of PF-04418948 was assessed against related receptors and a panel of GPCRs, ion channels and enzymes. The ability of PF-04418948 to pharmacologically block EP(2) receptor function in vivo was tested in rats. KEY RESULTS: PF-04418948 inhibited prostaglandin E(2)(PGE(2))-induced increase in cAMP in cells expressing EP(2) receptors with a functional K(B) value of 1.8 nM. In human myometrium, PF-04418948 produced a parallel, rightward shift of the butaprost-induced inhibition of the contractions induced by electrical field stimulation with an apparent K(B) of 5.4 nM. In dog bronchiole and mouse trachea, PF-04418948 produced parallel rightward shifts of the PGE(2)-induced relaxation curve with a K(B) of 2.5 nM and an apparent K(B) of 1.3 nM respectively. Reversal of the PGE(2)-induced relaxation in the mouse trachea by PF-04418948 produced an IC(50) value of 2.7 nM. Given orally, PF-04418948 attenuated the butaprost-induced cutaneous blood flow response in rats. PF-04418948 was selective for EP(2) receptors over homologous and unrelated receptors, enzymes and channels. CONCLUSIONS AND IMPLICATIONS: PF-04418948 is an orally active, potent and selective surmountable EP(2) receptor antagonist that should aid further elaboration of EP(2) receptor function.

Pharmacological profiling of neuropeptides on rabbit vaginal wall and vaginal artery smooth muscle in vitro.

BACKGROUND AND PURPOSE: Hypothalamic neuropeptides centrally modulate sexual arousal. However, the role of neuropeptides in peripheral arousal has been ignored. Vascular and non-vascular smooth muscle relaxation in the vagina is important for female sexual arousal. To date, in vitro studies have focused on vaginal strips with no studies on vaginal arteries. The aim of this study was to compare the effects of sexual hypothalamic neuropeptides on rabbit vaginal wall strips and arteries. EXPERIMENTAL APPROACH: Tissue bath and wire myography techniques were used to measure isometric tension from strips and arteries, respectively. KEY RESULTS: Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) relaxed both preparations, effects that were only antagonized by the VIP/PACAP antagonist VIP6-28 (10 nM) and the PAC(1) antagonist PACAP 6-38 (1 microM). The melanocortin agonist alpha-melanocortin-stimulating hormone (1 microM), but not bremelanotide (1 microM), also relaxed both preparations. Oxytocin and vasopressin contracted vaginal preparations, which could be antagonized by the V(1A) antagonist SR 49059. Neuropeptide Y (NPY) and the NPY Y(1) agonist Leu(31), Pro(34) NPY only contracted arteries, which was antagonized by the NPY Y(1) receptor antagonist BIBP 3226. Melanin-concentrating hormone (MCH; 1 microM) contracted arteries. CONCLUSION AND IMPLICATIONS: Hypothalamic neuropeptides can exert contractile and relaxant effects on vaginal strips and arteries. NPY Y(1), V(1A), MCH(1) antagonists as well as VIP/PAC(1) agonists may have therapeutic potential in both central and peripheral female sexual arousal. Differences in effect of neuropeptides between preparations raise the question of which preparation is important for female sexual arousal.