Identification of a new bisindolinone arresting IGROV1 cells proliferation

In an initial screening, a series of novel Knoevenagel adducts were submitted to the National Cancer Institute for evaluation of antitumor activity in human cell lines. In particular, compound 5f showed remarkable selectivity against IGROV1, an ovarian cancer cell line, without affecting healthy human fibroblast cells. Analyses of cytotoxicity, cell proliferation, cell migration, epigenetic changes, gene expression, and DNA damage were performed to obtain detailed information about its antitumor properties. Our results show that 5f causes proliferation arrest, decrease in motility, histone hyperacetylation, downregulation of cyclin D1 and α5 subunit of integrin β1 gene transcription. In addition, 5f treatment reduces transcript and protein levels of cyclin D1, which increases sensitivity to ionizing radiation and results in DNA damage comparable to cyclin D1 gene silencing.

Epigallocatechin-3-gallate Delivered in Nanoparticles Increases Cytotoxicity in Three Breast Carcinoma Cell Lines

The anticancer activity of epigallocatechin-3-gallate (EGCG), orally administrated, is limited by poor bioavailability, absorption, and unpredictable distribution in human tissues. EGCG charged nanoparticles may represent an opportunity to overcome these limitations. We assayed two different kinds of lipid nanoparticles (LNPs and LNPs functionalized with folic acid) charged with EGCG on three breast carcinoma cell lines (MCF-7, MDA-MB-231, and MCF-7TAM) and the human normal MCF10A mammary epithelial cells. Both LNPs loaded with EGCG, at low concentrations, induced a significant cytotoxicity in the three breast carcinoma cells but not in MCF10A cells. In view of a future application, both LNPs and LNPs-FA were found to be very suitable for in vitro studies and useful to improve EGCG administration in vivo. Since they are produced by inexpensive procedures using bioavailable, biocompatible, and biodegradable molecules, they represent an applicable tool for a more rationale use of EGCG as an anti-cancer agent.

Gene expression profile of human colon cancer cells treated with cross-reacting material 197, a diphtheria toxin non-toxic mutant

Cross-Reacting Material 197 (CRM197) is a diphtheria toxin non-toxic mutant that has shown antitumor activity in mice and humans. It is still unclear whether this anti-tumorigenic effect depends on its strong inflammatory-immunological property, its ability to inhibit heparin-binding epidermal growth factor (HB-EGF), or even its possible weak toxicity. CRM197 is utilized as a specific inhibitor of HB-EGF that competes for the epidermal growth factor receptor (EGFR), overexpressed in colorectal cancer and implicated in its progression. In this study we evaluate the effects of CRM197 on HT-29 human colon cancer cell line behaviour and, for CRM197 recognized ability to inhibit HB-EGF, its possible influence on EGFR activation. In particular, while HT-29 does not show any reduction of viability after CRM197 treatment (MTT modified assay), or changes in cell cycle distribution (flow cytometry), in EGFR localization, phospho-EGFR detected signals (immunohistochemistry) or in morphology (scanning electron microscopy, SEM) they show a change in the gene expression profile by microarray analysis (cDNA microarray SS-H19k8). The overexpression of genes like protein phosphatase 2, catalytic subunit, alpha isozyme (PPP2CA), guanine nucleotide-binding protein G subunit alpha-1(GNAI1) and butyrophilin, subfamily 2, member A1 (BTN2A1) has been confirmed with real-time-qPCR. This is the first study where the CRM197 treatment on HT-29 shows a possible scarce implication of endogenous HB-EGF on EGFR expression and cancer cell development. At the same time, our results show the alteration of a specific and selected number of genes.

Lithium induces mortality in medulloblastoma cell lines

Lithium is the main therapeutic agent for the treatment of bipolar disorders but nerve cells are not the sole target of this drug. Indeed, lithium has been reported to target numerous cell types and to affect cell proliferation, differentiation and death. Lithium targets a variety of enzymes among which there is GSK-3beta and a number of cell responses elicited by lithium are mediated by the Wnt pathway that is involved in medulloblastoma (MB) pathogenesis. We studied the in vitro effects of lithium on two different MB cell lines: D283MED and DAOY. High doses of lithium inhibited GSK3-beta, decreased cell proliferation and induced non-apoptotic cell death in both cell lines independently by intracellular levels of beta-catenin that is consistently high only in D283MED. At clinical doses, the anti-neoplastic effects were observed only in this cell line, highlighting the importance of a specific molecular background in determining the target therapy response. In conclusion, lithium could be a promising drug in MB, but an accurate molecular profile predictive of drug response still needs to be clarified.

Antitumor activity of new substituted 3-(5-imidazo[2,1-b]thiazolylmethylene)-2-indolinones and 3-(5-imidazo[2,1-b]thiadiazolylmethylene)-2-indolinones: selectivity against colon tumor cells and effect on cell cycle-related events

The synthesis of new 3-(5-imidazo[2,1-b]thiazolylmethylene)-2-indolinones and 3-(5-imidazo[2,1-b]thiadiazolylmethylene)-2-indolinones is reported. The antitumor activity was evaluated according to the protocols available at the National Cancer Institute (NCI), Bethesda, MD. To investigate the mechanism of action of the most potent antitumor agent of this series, its effect on growth of HT-29 colon carcinoma cells was studied. Its ability to inhibit cellular proliferation was mediated by cell cycle arrest at the G2/M phase, accompanied by inhibition of ornithine decarboxylase (ODC), the limiting enzyme of polyamine synthesis, and followed by induction of apoptosis.

Displayed correlation between gene expression profiles and submicroscopic alterations in response to cetuximab, gefitinib and EGF in human colon cancer cell lines

Background

EGFR is frequently overexpressed in colon cancer. We characterized HT-29 and Caco-2, human colon cancer cell lines, untreated and treated with cetuximab or gefitinib alone and in combination with EGF.

Methods

Cell growth was determined using a variation on the MTT assay. Cell-cycle analysis was conducted by flow cytometry. Immunohistochemistry was performed to evaluate EGFR expression and scanning electron microscopy (SEM) evidenced the ultrastructural morphology. Gene expression profiling was performed using hybridization of the microarray Ocimum Pan Human 40 K array A.

Results

Caco-2 and HT-29 were respectively 66.25 and 59.24 % in G0/G1. They maintained this level of cell cycle distribution after treatment, suggesting a predominantly differentiated state. Treatment of Caco-2 with EGF or the two EGFR inhibitors produced a significant reduction in their viability. SEM clearly showed morphological cellular transformations in the direction of cellular death in both cell lines treated with EGFR inhibitors. HT-29 and Caco-2 displayed an important reduction of the microvilli (which also lose their erect position in Caco-2), possibly invalidating microvilli absorption function. HT-29 treated with cetuximab lost their boundary contacts and showed filipodi; when treated with gefitinib, they showed some vesicles: generally membrane reshaping is evident. Both cell lines showed a similar behavior in terms of on/off switched genes upon treatment with cetuximab. The gefitinib global gene expression pattern was different for the 2 cell lines; gefitinib treatment induced more changes, but directly correlated with EGF treatment.

In cetuximab or gefitinib plus EGF treatments there was possible summation of the morphological effects: cells seemed more weakly affected by the transformation towards apoptosis. The genes appeared to be less stimulated than for single drug cases.

Conclusion

This is the first study to have systematically investigated the effect of cetuximab or gefitinib, alone and in combination with EGF, on human colon cancer cell lines. The EGFR inhibitors have a weaker effect in the presence of EGF that binds EGFR. Cetuximab treatment showed an expression pattern that inversely correlates with EGF treatment. We found interesting cyto-morphological features closely relating to gene expression profile. Both drugs have an effect on differentiation towards cellular death.

An ionotropic but not a metabotropic glutamate agonist potentiates the pharmacological effects of olanzapine in the rat

This study aimed to evaluate the possible potentiating action of ionotropic or metabotropic (metabotropic glutamate receptor type 5) glutamate agonists on pharmacological effects induced in rats by the atypical antipsychotic olanzapine. The administration of doses of olanzapine, which did not affect spontaneous motility, inhibited behaviors induced by the selective stimulation of 5HT(2A) and D(2) receptors. In particular, 0.03 or 0.06 mg/kg of olanzapine was sufficient to reduce, respectively, head shakes induced by the 5HT(2A) agonist 1-2,5-dimethoxy-4-iodophenyl-2-aminopropane (1 mg/kg) or hypermotility elicited by the D(2) stimulant quinpirole (0.15 mg/kg). Behavioral responses to a D(1)/D(2) agonist (apomorphine-induced stereotypies) were inhibited by doses of olanzapine that also influenced spontaneous behavior. The concomitant administration of D-cycloserine, an agonist at the glycine site on the N-methyl-D-aspartate receptor complex, given at a dose (3 mg/kg) that did not affect behavior, increased the inhibitory effect of olanzapine on the responses produced by 5HT2A, D(2) and D(1)/D(2) receptor stimulation. The concomitant administration of 2-chloro-5-hydroxyphenylglycine, an agonist of metabotropic glutamate receptor type 5, increased the inhibitory effect of olanzapine on the behaviors induced by the stimulation of D(2), but not 5HT2A or D(1)/D(2) receptors. As the effect on the serotonergic system seems important for the unusual pharmacological profile of atypical antipsychotics, the present results suggest that N-methyl-D-aspartate, but not metabotropic glutamate receptor type 5 agonists could be seen as promising therapeutic agents for increasing the pharmacological effects of olanzapine.

Repeated administration of the novel antipsychotic olanzapine does not modulate NMDA-sensitive glutamate and 5HT2 serotonin receptors in rats

Antipsychotic drugs reportedly show a common property in facilitating glutamatergic transmission in rat cerebral cortex. Since the binding of the radiolabelled channel blocker [3H]-MK801 is generally considered an affordable index of N-methyl-d-aspartate (NMDA)-sensitive glutamate receptor activation, we examined the effects of clinically effective treatment (3 weeks, daily administration) of the atypical antipsychotic drug olanzapine (32 micromol/kg/5 ml) on the specific binding of [3H]-MK801 specific binding and on the strychnine-insensitive glycine sites (glycine B) in synaptic plasma membranes (SPM) prepared from the medial prefrontal cortex (mPFC) of rats sacrificed after different (24, 60, 120 h) washout periods. We studied also the effects of repeated olanzapine administration on [3H]-ketanserin binding to 5HT2A receptors to verify whether, consistent with previously reported paradoxical effects of repeated administration of 5HT2A antagonists, this drug decreases 5HT2A receptor density without changing the apparent affinity. Neither single nor repeated olanzapine administration changed the kinetic characteristics of [3H]-MK801 or [3H]-glycine specific binding. When rats were sacrificed 120 h after the last olanzapine administration, both single or repeated treatment had failed to change the kinetic characteristics of [3H]-ketanserin binding, while the apparent affinity of 5HT2A receptors was increased in animals sacrificed at shorter (60 h) washout periods. Owing to the long half-life of olanzapine (24 h), and since the drug concentrations in mPFC of rats sacrificed 60 h after a single olanzapine administration (about 50 nM) are high enough to induce changes in 5HT2A receptor affinity, it is concluded that this modification, probably unrelated to the therapeutic efficacy, could be due to some drug still present in the brain at the time of the sacrifice.

Nafadotride administration increases D1 and D1/D2 dopamine receptor mediated behaviors

The administration of nafadotride, given at doses known to block the D3 dopamine receptors (0.75, 1.5, 3 mg/kg i.p.) increased locomotor activity both in naive and habituated rats and counteracted the hypothermia but not the hypomotility induced by a low dose of the putative D3 dopamine agonist (+/-)-7-hydroxy-2-(di-N-propylamino)-tetralin (7-OH-DPAT; 0.04 mg/kg). Nafadotride did not antagonize either the motor effects induced by different doses of the D2 agonist quinpirole (0.05 and 0.3 mg/kg) or the hypermotility induced by 7-OH-DPAT given at a dose (0.32 mg/kg) stimulating D2 dopamine receptors. The same nafadotride doses potentiated the grooming behavior induced by the D1 dopamine agonist SKF 38393 (10 mg/kg i.p.) as well as the stereotyped response to the D1/D2 agonist apomorphine (0.5 mg/kg s.c.). Stereotyped behavior was also observed in rats concomitantly treated with nafadotride and the D2 agonist quinpirole. As the activation of D1 dopamine receptors plays an important role in the occurrence of stereotypies, the results suggest that the blockade of D3 receptors by nafadotride could have favored D1/D2 dopamine receptor-mediated behaviors by potentiating D1 receptor function.

The activation of serotonin receptors prevents glutamate-induced neurotoxicity and NMDA-stimulated cGMP accumulation in primary cortical cell cultures

In the present study, we performed experiments on primary cell cultures from rat neocortex to assess the effects of the selective serotonergic 5HT(1A), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) or 5HT(2), (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) agonists on neuronal death induced by 15min exposure to (-)glutamate (300 microM) as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The results show that both drugs attenuated (-)glutamate-induced neurotoxicity and this effect was fully antagonized by the selective antagonists of 5HT(1) (NAN-190) or 5HT(2) (ketanserin) receptors.The effects of the selective serotonergic agonists on the production of cyclic GMP (cGMP) accumulation induced by N-methyl-D-aspartate (NMDA) in the same neuronal preparation were also evaluated. Only the 5HT(2) agent, but not 8-OH-DPAT, per se, decreased basal cGMP levels. In contrast, both drugs attenuated the NMDA-induced cGMP accumulation in this cell preparation. The unexpected similar behavior of 5HT(1) and 5HT(2) agonists towards glutamate-induced neurotoxicity and NMDA-induced cGMP accumulation in primary cell cultures is discussed. It is concluded that primary cell cultures from rat cerebral cortex could represent a suitable experimental model to search novel neuroleptics which exert their effects via 5HT receptors.

Anticonvulsant preclinical profile of CHF 3381: dopaminergic and glutamatergic mechanisms

Following intraperitoneal or oral administrations, CHF 3381 ([n-(2-indanyl)-glycinamide hydrochloride]) protected rats against maximal electroshock (MES) test seizures. As glutamatergic pathways play a pivotal role in epilepsy, to better characterize the molecular mechanisms of action of CHF 3381, the drug effects on the binding of the excitatory amino acid antagonist [3H]-MK-801 in the presence of n-methyl-D-aspartate (NMDA), spermidine, or the combination of both ligands, were studied. CHF 3381 inhibited the [3H]-MK-801 specific binding in a noncompetitive fashion in respect to NMDA and polyamines recognition sites. CHF 3381 failed to change the kinetic characteristic of glycine B receptors labeled with [3H]-glycine; in contrast, it significantly increased K(d) values when the receptors were labeled with the more specific compound [3H]-MDL 105,519. CHF 3381 antagonized dopamine (DA)-induced behavioral responses and inhibited, in a glycine-dependent manner, the NMDA-induced [3H]-DA release from rat striatal slices, but it failed to change either the kinetic characteristics of D1, D2, or D3 receptors in synaptic plasma membranes (SPM) or the [3H]-DA uptake from striatal synaptosomes. Moreover, in primary cell cultures of cortical neurons, this drug exhibited glycine-independent neuroprotective effects against glutamate-induced excitotoxicity. It is concluded that this compound could have a potential use in several disease states where a pathological high level of NMDA receptor activation is thought to occur.

Inhibition of free radical production or free radical scavenging protects from the excitotoxic cell death mediated by glutamate in cultures of cerebellar granule neurons

Glutamate kills sensitive neurons through several steps downstream to receptor activation: increased free Ca2+ levels, activation of various enzymes and accumulation of reactive oxygen species (ROS). We have evaluated in a well established model of neuronal cultures the neuroprotective effects of blocking these mechanisms, either singularly or by combining multiple enzyme inhibition and/or ROS scavenging. In vitro cultures of cerebellar granule cells exposed to a toxic concentration of glutamate (100 microM for 15 min in the absence of Mg2+) combined with several pharmacological treatments. Inhibition of nitric oxide synthase (NOS) and phospholipase A2 (PLA2) were effective in decreasing cell death and the combined treatments showed some degree of additivity. By contrast, inhibition of xanthine oxidase (XO) with allopurinol was uneffective. Antioxidants (in particular vitamin e or vitamin E analogs). protected neurons up to more than 50%. A synergistic effect was demonstrated by the combination of vitamin E and C. On the other hand, antioxidants did not increase the protection granted by enzyme inhibitors, suggesting that they act downstream to NOS and PLA2. In conclusion, NOS and PLA2 activated by Ca2+ influx give rise to reactive oxygen species whose deleterious action can be counteracted either by inhibiting these enzymes or by scavenging the excess of free radicals produced by them. Finally, a moderate protection was obtained by blocking protein synthesis with cycloheximide, suggesting a partial contribution of apoptotic mechanisms to the excitotoxic cell death.