A risk prediction model for head and neck cancers incorporating lifestyle factors, HPV serology and genetic markers.

Head and neck cancer is often diagnosed late and prognosis for most head and neck cancer patients remains poor. To aid early detection, we developed a risk prediction model based on demographic and lifestyle risk factors, human papillomavirus (HPV) serological markers and genetic markers. A total of 10 126 head and neck cancer cases and 5254 controls from five North American and European studies were included.

Preclinical Evidence for Combined Use of Aromatase Inhibitors and NSAIDs as Preventive Agents of Tobacco-Induced Lung Cancer.

Introduction: A hormonal role in NSCLC development is well documented. We previously showed that the aromatase inhibitor (AI) anastrozole decreased development of tobacco carcinogen-induced lung tumors in a murine lung cancer prevention model and that aromatase and estrogen receptor were expressed in pulmonary inflammatory cells.

Methods: We utilized a tobacco carcinogen-induced lung tumor mouse model by treatment with 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), to determine whether an AI combined with nonsteroidal anti-inflammatory drugs results in greater lung tumor prevention effects compared to single-agent treatment.

Differential response to 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) in non-small cell lung cancer cells with distinct oncogene mutations.

We previously demonstrated that non-small cell lung cancer (NSCLC) cells and primary human lung tumors aberrantly express the vitamin D3-catabolizing enzyme, CYP24, and that CYP24 restricts transcriptional regulation and growth control by 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) in NSCLC cells. To ascertain the basis for CYP24 dysregulation, we assembled a panel of cell lines that represent distinct molecular classes of lung cancer: cell lines were selected which harbored mutually exclusive mutations in either the K-ras or the Epidermal Growth Factor Receptor (EGFR) genes. We observed that K-ras mutant lines displayed a basal vitamin D receptor (VDR)(low)CYP24(high) phenotype, whereas EGFR mutant lines had a VDR(high)CYP24(low) phenotype.

CYP24 inhibition preserves 1α,25-dihydroxyvitamin D(3) anti-proliferative signaling in lung cancer cells.

Human lung tumors aberrantly express the 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3))-catabolizing enzyme, CYP24. We hypothesized that CYP24 reduces 1,25(OH)(2)D(3)-mediated transcription and allows lung cancer cells to escape its growth-inhibitory action. To test this, H292 lung cancer cells and the CYP24-selective inhibitor CTA091 were utilized.

A local effect of CYP24 inhibition on lung tumor xenograft exposure to 1,25-dihydroxyvitamin D(3) is revealed using a novel LC-MS/MS assay.

The vitamin D(3) catabolizing enzyme, CYP24, is frequently over-expressed in tumors, where it may support proliferation by eliminating the growth suppressive effects of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)). However, the impact of CYP24 expression in tumors or consequence of CYP24 inhibition on tumor levels of 1,25(OH)(2)D(3)in vivo has not been studied due to the lack of a suitable quantitative method. To address this need, an LC-MS/MS assay that permits absolute quantitation of 1,25(OH)(2)D(3) in plasma and tumor was developed.

Vorinostat increases carboplatin and paclitaxel activity in non-small-cell lung cancer cells.

We observed a 53% response rate in non-small cell lung cancer (NSCLC) patients treated with vorinostat plus paclitaxel/carboplatin in a Phase I trial. Studies were undertaken to investigate the mechanism (s) underlying this activity. Growth inhibition was assessed in NSCLC cells by MTT assay after 72 hr of continuous drug exposure.

Breast cancer-derived M543V mutation in helix 12 of estrogen receptor alpha inverts response to estrogen and SERMs.

We have isolated from human breast cancers several mutations in the Helix 12 component of activation function 2 (AF-2) in the estrogen receptor alpha (ERalpha). We used a novel approach to detect changes in the hormone-binding domain of ERalpha, based on the evidence that antiestrogens, such as 4-hydroxytamoxifen (ZOHT) and ICI 182,780, block the function of ERalpha by binding and folding the AF-2 transcriptional domain in a way that inhibits its association with coactivator proteins. We have identified a Helix 12 mutation, M543V, which leads to greater ERalpha transcription with ZOHT and other antiestrogens (including 1,1-dichloro-2,2,3-triarylcyclopropanes, DTACs) than with 17-beta estradiol (E2).

Estrogen receptor beta (ERbeta) subtype-specific ligands increase transcription, p44/p42 mitogen activated protein kinase (MAPK) activation and growth in human non-small cell lung cancer cells.

In non-small cell lung cancer (NSCLC) cells, 17beta-estradiol increases transcription, activates MAPK, and stimulates proliferation. We hypothesize that estrogen receptor beta (ERbeta) mediates these responses because it, but not ERalpha, is detected in our NSCLC cell lines. To test this, we determined the effects of the ERbeta-selective agonists genistein (GEN) and 2,3-bis(4-hydroxyphenyl)propionitrile (DPN) and the ERalpha-selective agonist 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) in 201T cells.

CYP24, the enzyme that catabolizes the antiproliferative agent vitamin D, is increased in lung cancer.

1Alpha,25-dihydroxyvitamin D3 (1,25D3) displays potent antiproliferative activity in a variety of tumor model systems and is currently under investigation in clinical trials in cancer. Studies were initiated to explore its potential in nonsmall cell lung cancer (NSCLC), as effective approaches to the treatment of that disease are needed. In evaluating factors that may affect activity in NSCLC, the authors found that CYP24 (25-hydroxyvitamin D3-24-hydroxylase), the enzyme that catabolizes 1,25D3, is frequently expressed in NSCLC cell lines but not in the nontumorigenic bronchial epithelial cell line, Beas2B.

Synaptic localization of a functional NADPH oxidase in the mouse hippocampus.

Superoxide has been shown to be critical for hippocampal long-term potentiation (LTP) and hippocampus-dependent memory function. A possible source for the generation of superoxide during these processes is NADPH oxidase. The active oxidase consists of two membrane proteins, gp91phox and p22phox, and four cytosolic proteins, p40phox, p47phox, p67phox, and Rac.

Regulation of endogenous gene expression in human non-small cell lung cancer cells by estrogen receptor ligands.

Estrogen receptor (ER) agonists and antagonists elicit distinct responses in non-small cell lung cancer (NSCLC) cells. To determine how such responses are generated, the expression of ERalpha, ERbeta, and ER coregulators in human lung fibroblasts and human NSCLC cell lines was evaluated by immunoblot. Ligand-dependent estrogenic responses in NSCLC cells are probably generated via ERbeta and the p160 coactivator GRIP1/TIF2, because expression of these proteins was detected, but not full-length ERalpha or the p160 coactivator SRC-1.

Inhibition of estrogen receptor alpha-mediated transcription by antiestrogenic 1,1-dichloro-2,2,3-triarylcyclopropanes.

A novel class of pure antiestrogens, 1,1-dichloro-2,2,3-triarylcyclopropanes (DTACs), lack estrogenic activity in a mouse uterotrophic assay and inhibit the growth of estrogen-sensitive MCF-7 breast cancer cells (Day et al., 1991). Here, reporter assays were used to evaluate the effects of the DTACs on estrogen receptor alpha (ERalpha)-mediated transcription from either classic estrogen-response elements (EREs) or nonclassic AP-1 elements.

Long-term depression in the adult hippocampus in vivo involves activation of extracellular signal-regulated kinase and phosphorylation of Elk-1.

Protein kinase cascades likely play a critical role in the signaling events that underlie synaptic plasticity and memory. The extracellular signal-regulated kinase (ERK) cascade is suited well for such a role because its targets include regulators of gene expression. Here we report that the ERK cascade is recruited during long-term depression (LTD) of synaptic strength in area CA1 of the adult hippocampus in vivo and selectively impacts on phosphorylation of the nuclear transcription factor Elk-1.

Peroxynitrite-induced tyrosine nitration and inhibition of protein kinase C.

Protein kinase C (PKC) is an important intracellular signaling molecule whose activity is essential for a number of aspects of neuronal function including synaptic plasticity. We investigated the regulation of PKC activity by reactive nitrogen species in order to examine whether such species regulate PKC in neurons. Neither autonomous nor cofactor-dependent PKC activity was altered when either hippocampal homogenates or rat brain purified PKC were incubated briefly with three different nitric oxide donor compounds.

Impairment of long-term potentiation and associative memory in mice that overexpress extracellular superoxide dismutase.

Reactive oxygen species, including superoxide, generally are considered neurotoxic molecules whose effects can be alleviated by antioxidants. Different from this view, we show that scavenging of superoxide with an antioxidant enzyme is associated with deficits in hippocampal long-term potentiation (LTP), a putative neural substrate of memory, and hippocampal-mediated memory function. Using transgenic mice that overexpress extracellular superoxide dismutase (EC-SOD), a superoxide scavenger, we found that LTP was impaired in hippocampal area CA1 despite normal LTP in area CA3.

Protein phosphatase-mediated regulation of protein kinase C during long-term depression in the adult hippocampus in vivo.

The neural substrates of learning and memory are thought to involve use-dependent long-term changes in synaptic function, including long-term depression (LTD) of synaptic strength. One biochemical event hypothesized to contribute to the maintenance and expression of LTD is decreased protein phosphorylation, caused by a decrease in protein kinase activity and/or an increase in protein phosphatase activity. We tested whether the activity of protein kinase C (PKC) decreases after the induction of LTD in area CA1 of the adult hippocampus in vivo, and then investigated the mechanism responsible for the LTD-associated alteration in PKC activity.

The extracellular signal-regulated kinase cascade is required for NMDA receptor-independent LTP in area CA1 but not area CA3 of the hippocampus.

Activation of extracellular signal-regulated kinase (ERK) has been shown to be necessary for NMDA receptor-dependent long-term potentiation (LTP). We studied the role of ERK in three forms of NMDA receptor-independent LTP: LTP induced by very high-frequency stimulation (200 Hz-LTP), LTP induced by the K(+) channel blocker tetraethylammonium (TEA) (TEA-LTP), and mossy fiber (MF) LTP (MF-LTP). We found that ERK was activated in area CA1 after the induction of both 200 Hz-LTP and TEA-LTP and that this activation required the influx of Ca(2+) through voltage-gated Ca(2+) channels.

Glutamate-induced neuron death requires mitochondrial calcium uptake.

We have investigated the role of mitochondrial calcium buffering in excitotoxic cell death. Glutamate acts at NMDA receptors in cultured rat forebrain neurons to increase the intracellular free calcium concentration. Although concurrent inhibition of mitochondrial calcium uptake substantially enhanced this cytoplasmic calcium increase, it significantly reduced glutamate-stimulated neuronal cell death.

Stimulation of p42 and p44 mitogen-activated protein kinases by reactive oxygen species and nitric oxide in hippocampus.

Reactive oxygen species (ROS) have been suggested to act as cellular messengers that mediate signal transduction cascades in various cell types. However, little is known about their role in this capacity in the nervous system. We have begun to investigate the role of ROS, and that of nitric oxide (NO), in mediating mitogen-activated protein kinase (MAPK) signaling in rat hippocampal slices.

Daily rhythms in spontaneous and diazepam-induced anxiolysis in Syrian hamsters.

The diurnal variations in spontaneous and diazepam-induced anxiolysis and exploratory behavior were examined in Syrian hamsters in a plus-maze paradigm. The administration of diazepam or flunitrazepam augmented the percentage of time spent in the open arms, the percentage of entries to the open arms, and the number of crosses to both arms, whereas ethyl-beta-carboline injection decreased them. These three behavioral parameters showed significant daily variations, with the maxima being found at night (2400-0400 h).

Daily variations in GABA receptor function in Syrian hamster cerebral cortex.

The existence of diurnal changes in postsynaptic expression of gamma-aminobutyric acid (GABA) type A receptors was assessed in cerebral cortex of Syrian hamsters by measuring [3H]GABA binding and the influx of 36Cl- in synaptoneurosomes. A diurnal variation in dissociation constant of [3H]GABA binding to cerebral cortex membranes, and the absence of diurnal differences in maximal number of sites, were found. When the nycthemeral changes in muscimol-stimulated 36Cl- uptake by cortical synaptoneurosomes were assessed, a maximum occurred late at night (i.

Increased pineal melatonin content coupled to restricted water availability in a Pavlovian conditioning paradigm in rats.

The objective of this study was to assess whether rat pineal melatonin content could be modified in a classical conditioning paradigm. In rats kept under light (200 lux) from 06.00 to 18.

Diurnal changes of GABA turnover rate in brain and pineal gland of Syrian hamsters.

Circadian rhythms of GABA turnover rate in cerebral cortex, preoptic area-medial basal hypothalamus (PMBH), cerebellum, and pineal gland were examined in Syrian hamsters kept for 3 months under either long (14 h of light/day) or short days (10 h of light/day). In vivo GABA turnover rate was measured by the increase of GABA levels following inhibition of GABA-transaminase by gamma-acetylenic GABA. Under long photoperiods, a significant rhythm of GABA turnover was detected in the four areas studied (cerebral cortex, PMBH, cerebellum, and pineal gland), with maxima at night.

GABA activity in dispersed bovine pineal cells: effect on serotonin release and calcium and chloride uptake.

The presence of gamma-aminobutyric acid (GABA) and peripheral and central benzodiazepine receptors in the mammalian pineal gland prompted the examination of GABAergic transmission in dispersed bovine pineal cells. The effect of GABA on 3H-serotonin (5HT) release was examined in bovine pineal cells. GABA, by acting through GABA B receptor subtype, decreased 5HT release and by acting through GABA B, and presumably through GABA A receptor subtypes, inhibited depolarization-induced 45Ca2+ uptake in bovine pinealocytes.