Cannabis Sativa Oil Promotes Social Interaction and Ultrasonic Communication by Acting on Oxytocin Pathway.

Objective: Cannabis sativa is the most used recreational drug worldwide. In recent years, there has been a growing interest in the potential therapeutic benefits of medicinal cannabis to treat a variety of psychiatric and neurological conditions. In particular, cannabidiol (CBD), a nonpsychoactive cannabis constituent, has been investigated for its potential prosocial effects on behavior, although the molecular mechanisms underlying this effect are still largely unknown. The aim of this study was to investigate the effect of a C. sativa oil CBD rich (CS oil) on social interaction and ultrasonic communication in mice. Study Design: Twenty-seven adult male mice (B6; 129P F2) were treated daily with vehicle or CS oil for 2 weeks. At Day 14, mice were tested for behavior (social interaction test and ultrasonic communication). Forty minutes before the behavioral tests, mice were exposed to intranasal treatment with vehicle or the oxytocin receptor antagonist, L-371,257. After behavioral tests, VH- and CS oil-treated mice were sacrificed, RNA was extracted from the hypothalamus and used for quantitative Real Time-PCR experiments. Results: We found that a 2-week treatment with the CS oil on mice exerted a prosocial effect associated with an increase in ultrasonic vocalizations. These effects were inhibited by pretreating mice with an oxytocin receptor antagonist. In addition, at the molecular level, we found that CS oil treatment caused a significant increase in oxytocin and a decrease in oxytocin receptor expression levels in the brain hypothalamus. Conclusion: Our results suggest that CS oil promotes social behavior by acting on oxytocin pathway.

Exploring ultrasonic communication in mice treated with Cannabis sativa oil: Audio data processing and correlation study with different behaviours.

Studying ultrasonic vocalizations (USVs) plays a crucial role in understanding animal communication, particularly in the field of ethology and neuropharmacology. Communication is associated with social behaviour; so, USVs study is a valid assay in behavioural readout and monitoring in this context. This paper delved into an investigation of ultrasonic communication in mice treated with Cannabis sativa oil (CS mice), which has been demonstrated having a prosocial effect on behaviour of mice, versus control mice (vehicle-treated, VH mice). To conduct this study, we created a dataset by recording audio-video files and annotating the duration of time that test mice spent engaging in social activities, along with categorizing the types of emitted USVs. The analysis encompassed the frequency of individual sounds as well as more complex sequences of consecutive syllables (patterns). The primary goal was to examine the extent and nature of diversity in ultrasonic communication patterns emitted by these two groups of mice. As a result, we observed statistically significant differences for each considered pattern length between the two groups of mice. Additionally, the study extended its research by considering specific behaviours, aiming to ascertain whether dissimilarities in ultrasonic communication between CS and VH mice are more pronounced or subtle within distinct behavioural contexts. Our findings suggest that while there is variation in USV communication between the two groups of mice, the degree of this diversity may vary depending on the specific behaviour being observed.

Multi-Cell Line Analysis of Lysosomal Proteomes Reveals Unique Features and Novel Lysosomal Proteins.

Lysosomes, the main degradative organelles of mammalian cells, play a key role in the regulation of metabolism. It is becoming more and more apparent that they are highly active, diverse, and involved in a large variety of processes. The essential role of lysosomes is exemplified by the detrimental consequences of their malfunction, which can result in lysosomal storage disorders, neurodegenerative diseases, and cancer. Using lysosome enrichment and mass spectrometry, we investigated the lysosomal proteomes of HEK293, HeLa, HuH-7, SH-SY5Y, MEF, and NIH3T3 cells. We provide evidence on a large scale for cell type-specific differences of lysosomes, showing that levels of distinct lysosomal proteins are highly variable within one cell type, while expression of others is highly conserved across several cell lines. Using differentially stable isotope-labeled cells and bimodal distribution analysis, we furthermore identify a high confidence population of lysosomal proteins for each cell line. Multi-cell line correlation of these data reveals potential novel lysosomal proteins, and we confirm lysosomal localization for six candidates. All data are available via ProteomeXchange with identifier PXD020600.

Cytotoxic effects of targeted agent alone or with chemotherapy in the treatment of adenoid cystic carcinoma: a preclinical study.

Adenoid cystic carcinoma (ACC) is a rare malignancy characterized by high incidence of relapse. When relapsing, ACC has an indolent but relentless behaviour, thus leading to a poor long-term prognosis. The treatment of choice of relapsing ACC remains surgery followed by radiotherapy, whenever feasible. Therapeutic weapons are limited to systemic drugs. The most widely used chemotherapy regimen is the combination of cisplatin and doxorubicin, however with low response rate and not long lasting; there is also a lack of alternatives for second line therapies in case of disease progression. Therefore, a more comprehensive strategy aimed at identifying at preclinical level the most promising drugs or combination is clearly needed. In this study, the cytotoxic effects of two standard chemotherapy drugs, cisplatin and doxorubicin, and of five targeted therapy-drugs was tested in vitro, on an h-TERT immortalized ACC cell line, and in vivo, on zebrafish embryos with ACC tumoral cell xenograft. Then, combinations of one standard chemotherapy drug plus one targeted therapy drug were also evaluated, in order to find the best treatment strategy for ACC. Data obtained demonstrated that both vorinostat and olaparib significantly increased the standard chemotherapy cytotoxic effects, suggesting new interesting therapeutic options for ACC.

Prognosis and management of recurrent and/or metastatic head and neck adenoid cystic carcinoma.

Adenoid cystic carcinoma (ACC) is a rare tumor, usually arising in the salivary gland, accounting for 1% of all head and neck cancers. ACC may have a long-term poor prognosis, as about 40% of radically treated patients will recur locoregionally and up to 60% will develop distant metastasis. Factors influencing risk of recurrence have been well studied, but few data exist about prognostic factors in Recurrent/Metastatic (RM) setting. Moreover, treatment of RM ACC is often a challenge for clinicians, in the context of a rare disease, which may have an indolent clinical behavior or less frequently a quicker growth and with a paucity of available clinical trials. This review critically analyzes pathological and molecular prognostic factors in RM ACC and make an overview on actual therapeutic choices and future direction of therapy. Recognized prognostic factors in RM ACC are the presence and site of distant metastasis (lung vs other), the presence of nodal metastasis and of extranodal extension, skull base recurrence, disease free interval, lymphovascular invasion, solid histotypes and grading of disease, and the presence of mutation of NOTCH1 family, PI3K, and TP53. Due to disappointing results with chemotherapy, new approaches are under study, also on the basis of biomolecular research. Ongoing clinical trials are evaluating treatment targeting MYB and NOTCH1 alterations, immunotherapy or combination of targeted treatments and immune checkpoint inhibitors.

Protective Effects of Gynostemma pentaphyllum (var. Ginpent) against Lipopolysaccharide-Induced Inflammation and Motor Alteration in Mice.

Gynostemma pentaphyllum (var. Ginpent) (GP) is a variety of Cucurbit with anti-inflammatory and antioxidant effects in patients. In this manuscript, the main components present in the dry extract of GP have been identified using Ultra High Performance Liquid Chromatography quadrupole-time-of-flight mass spectrometry (UHPLC/Q-TOF-MS). In addition, the anti-inflammatory action of GP was evaluated in animal models with acute peripheral inflammation and motor alteration induced by lipopolysaccharide. The results showed that GP dry extract is rich in secondary metabolites with potential antioxidant and anti-inflammatory properties. We found that the treatment with GP induced a recovery of motor function measured with the rotarod test and pole test, and a reduction in inflammatory cytokines such as interleukin-1ß and interleukin-6 measured with the ELISA test. The data collected in this study on the effects of GP in in vivo models may help integrate the therapeutic strategies of inflammatory-based disorders.

Cytotoxic Effect of Trabectedin In Human Adrenocortical Carcinoma Cell Lines and Primary Cells.

Mitotane is the only drug approved for the treatment of adrenocortical carcinoma (ACC). The regimen to be added to mitotane is a chemotherapy including etoposide, doxorubicin, and cisplatin. This pharmacological approach, however, has a limited efficacy and significant toxicity. Evidence indicates that ACC seems to be sensitive to alkylating agents. Trabectedin is an anti-tumor drug that acts as an alkylating agent with a complex mechanism of action. Here, we investigated whether trabectedin could exert a cytotoxic activity in in vitro cell models of ACC. Cell viability was evaluated by MTT assay on ACC cell lines and primary cell cultures. The gene expression was evaluated by q-RT-PCR, while protein expression and localization were studied by Western blot and immunocytochemistry. Combination experiments were performed to evaluate their interaction on ACC cell line viability. Trabectedin demonstrated high cytotoxicity at sub-nanomolar concentrations in ACC cell lines and patient-derived primary cell cultures. The drug was able to reduce /ß catenin nuclear localization, although it is unclear whether this effect is involved in the observed cytotoxicity. Trabectedin/mitotane combination exerted a synergic cytotoxic effect in NCI-H295R cells. Trabectedin has antineoplastic activity in ACC cells. The synergistic cytotoxic activity of trabectedin with mitotane provides the rationale for testing this combination in a clinical study.

Cannabimimetic plants: are they new cannabinoidergic modulators?

MAIN CONCLUSION: Phytochemicals and secondary metabolites able to interact with the endocannabinoid system (Cannabimimetics) have been recently described in a broad range of plants and fruits. These findings can open new alternative avenues to explore for the development of novel therapeutic compounds. The cannabinoids regulate many physiological and pathological functions in both animals and plants. Cannabis sativa is the main plant that produces phytocannabinoids inside resins capable to defend the plant from the aggression of parasites and herbivores. Animals produce anandamide and 2-arachidonoyl glycerol, which thanks to binding with main receptors such as type-1 cannabinoid receptor (CB1R) and the type-2 cannabinoid receptor (CB2R) are involved in inflammation processes and several brain functions. Endogenous cannabinoids, enzymes for synthesis and degradation of cannabinoids, and CB1R and CB2R constitute the endocannabinoid system (ECS). Other plants can produce cannabinoid-like molecules such as perrottetinene extracted from Radula perrottetii, or anandamide and 2-arachidonoyl glycerol extracted from some bryophytes. Moreover, several other secondary metabolites can also interact with the ECS of animals and take the name of cannabimimetics. These phytoextracts not derived from Cannabis sativa can act as receptor agonists or antagonist, or enzyme inhibitors of ECS and can be involved in the inflammation, oxidative stress, cancer, and neuroprotection. Finally, given the evolutionary heterogeneity of the cannabimimetic plants, some authors speculated on the fascinating thesis of the evolutionary convergence between plants and animals regarding biological functions of ECS. The review aims to provide a critical and complete assessment of the botanical, chemical and therapeutic aspects of cannabimimetic plants to evaluate their spread in the world and medicinal potentiality.

In vitro antitumor activity of progesterone in human adrenocortical carcinoma.

PURPOSE: The management of patients with adrenocortical carcinoma (ACC) is challenging. As mitotane and chemotherapy show limited efficacy, there is an urgent need to develop therapeutic approaches. The aim of this study was to investigate the antitumor activity of progesterone and explore the molecular mechanisms underlying its cytotoxic effects in the NCI-H295R cell line and primary cell cultures derived from ACC patients. METHODS: Cell viability, cell cycle, and apoptosis were analyzed in untreated and progesterone-treated ACC cells. The ability of progesterone to affect the Wnt/ß-catenin pathway in NCI-H295R cells was investigated by immunofluorescence. Progesterone and mitotane combination experiments were also performed to evaluate their interaction on NCI-H295R cell viability. RESULTS: We demonstrated that progesterone exerted a concentration-dependent inhibition of ACC cell viability. Apoptosis was the main mechanism, as demonstrated by a significant increase of apoptosis and cleaved-Caspase-3 levels. Reduction of ß-catenin nuclear translocation may contribute to the progesterone cytotoxic effect. The progesterone antineoplastic activity was synergically increased when mitotane was added to the cell culture medium. CONCLUSIONS: Our results show that progesterone has antineoplastic activity in ACC cells. The synergistic cytotoxic activity of progesterone with mitotane provides the rationale for testing this combination in a clinical study.

Favorable prognostic role of tropomodulins in neuroblastoma.

Neuroblastoma is a pediatric tumor of the sympatoadrenal lineage of the neural crest characterized by high molecular and clinical heterogeneity, which are the main causes of the poor response to standard multimodal therapy. The identification of new and selective biomarkers is important to improve our knowledge on the mechanisms of neuroblastoma progression and to find the targets for innovative cancer therapies. This study identifies a positive correlation among tropomodulins (TMODs) proteins expression and neuroblastoma progression. TMODs bind the pointed end of actin filaments, regulate polymerization and depolymerization processes modifying actin cytoskeletal dynamic and influencing neuronal development processes. Expression levels of TMODs genes were analyzed in 17 datasets comprising different types of tumors, including neuroblastoma, and it was demonstrated that high levels of tropomodulin1 (TMOD1) and tropomodulin 2 (TMOD2) correlate positively with high survival probability and with favorable clinical and molecular characteristics. Functional studies on neuroblastoma cell lines, showed that TMOD1 knockin induced cell cycle arrest, cell proliferation arrest and a mature functional differentiation. TMOD1 overexpression was responsible for particular cell morphology and biochemical changes which directed cells towards a neuronal favorable differentiation profile. TMOD1 downregulation also induced cell proliferation arrest but caused the loss of mature cell differentiation and promoted the development of neuroendocrine cellular characteristics, delineating an aggressive and unfavorable tumor behavior. Overall, these data indicated that TMODs are favorable prognostic biomarkers in neuroblastoma and we believe that they could contribute to unravel a new pathophysiological mechanism of neuroblastoma resistance contributing to the design of personalized therapeutics opportunities.

Antisecretive and Antitumor Activity of Abiraterone Acetate in Human Adrenocortical Cancer: A Preclinical Study.

CONTEXT: Patients with adrenocortical carcinoma (ACC) frequently suffer from cortisol excess, which portends a negative prognosis. Rapid control of cortisol hypersecretion and tumor growth are the main goals of ACC therapy. Abiraterone acetate (AA) is a potent inhibitor of 17alpha-hydroxylase/17,20-lyase, a key enzyme of adrenal steroidogenesis. OBJECTIVE: This study sought to investigate the therapeutic use of AA in preclinical models of ACC. DESIGN: AA antisecretive and antiproliferative effects were investigated in vitro using NCI-H295R and SW13 ACC cell lines and human primary ACC cell cultures, as well as in vivo using immunodeficient mice. METHODS: Steroid secretion, cell viability, and proliferation were analyzed in untreated and AA-treated ACC cells. The ability of AA to affect the Wnt/beta-catenin pathway in NCI-H295R cells was also analyzed. Progesterone receptor (PgR) gene was silenced by the RNA interference approach. The antitumor efficacy of AA was confirmed in vivo in NCI-H295R cells xenografted in immunodeficient mice. RESULTS: AA reduced the secretion of both cortisol and androgens, increased production of progesterone, and induced a concentration-dependent decrease of cell viability in the NCI-H295R cells and primary secreting ACC cultures. AA also reduced beta-catenin nuclear accumulation in NCI-H295R cells. AA administration to NCI-H295R-bearing mice enhanced progesterone levels and inhibited tumor growth. The cytotoxic effect of AA was prevented by either blocking PgR or by gene silencing. CONCLUSION: AA is able to inhibit hormone secretion and growth of ACC both in vitro and in vivo. It also reduces beta-catenin nuclear accumulation. The cytotoxic effect of AA seems to require PgR.

Inhibition of Survivin Is Associated with Zoledronic Acid-induced Apoptosis of Prostate Cancer Cells.

BACKGROUND/AIM: Evidence suggests that zoledronic acid (ZA) exerts direct antitumor effects on cancer cells but the underlying mechanisms of these actions are unknown. This study investigated the possible involvement of survivin in the antiproliferative effects of ZA in prostate cancer. MATERIALS AND METHODS: 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT) dye reduction assay was used to assess cell viability and acridine orange/ethidium bromide double staining to analyze cell death. Human Apoptosis Array evaluated the expression of apoptosis-related proteins. Survivin protein was measured by western blot technique and miR-203 levels were quantified by quantitative real-time polymerase chain reaction. RESULTS: ZA induced inhibition of cell proliferation and apoptosis activation, with down-regulation of survivin protein. A negative regulation at gene expression level may be hypothesized because we observed a significant decrease of survivin mRNA level and an increase of miR-203 expression after ZA exposure. CONCLUSION: This study provides evidence that ZA may directly inhibit cancer cell proliferation, identifying survivin as one of its downstream targets.

An Integrated Approach for a Structural and Functional Evaluation of Biosimilars: Implications for Erythropoietin.

BACKGROUND: Authorization to market a biosimilar product by the appropriate institutions is expected based on biosimilarity with its originator product. The analogy between the originator and its biosimilar(s) is assessed through safety, purity, and potency analyses. OBJECTIVE: In this study, we proposed a useful quality control system for rapid and economic primary screening of potential biosimilar drugs. For this purpose, chemical and functional characterization of the originator rhEPO alfa and two of its biosimilars was discussed. METHODS: Qualitative and quantitative analyses of the originator rhEPO alfa and its biosimilars were performed using reversed-phase high-performance liquid chromatography (RP-HPLC). The identification of proteins and the separation of isoforms were studied using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and two-dimensional gel electrophoresis (2D-PAGE), respectively. Furthermore, the biological activity of these drugs was measured both in vitro, evaluating the TF-1 cell proliferation rate, and in vivo, using the innovative experimental animal model of the zebrafish embryos. RESULTS: Chemical analyses showed that the quantitative concentrations of rhEPO alfa were in agreement with the labeled claims by the corresponding manufacturers. The qualitative analyses performed demonstrated that the three drugs were pure and that they had the same amino acid sequence. Chemical differences were found only at the level of isoforms containing N-glycosylation; however, functional in vitro and in vivo studies did not show any significant differences from a biosimilar point of view. CONCLUSION: These rapid and economic structural and functional analyses were effective in the evaluation of the biosimilarity between the originator rhEPO alfa and the biosimilars analyzed.

GPNMB/OA protein increases the invasiveness of human metastatic prostate cancer cell lines DU145 and PC3 through MMP-2 and MMP-9 activity.

Non-metastatic glycoprotein melanoma protein B (GPNMB), also known as osteoactivin (OA) is expressed in a wide array of tumors and represents an emerging target for drug development. In this study, we investigated the role of GPNMB/OA in the progression of human metastatic DU145 and PC3 prostate cancer cells. GPNMB/OA contribution in PCa malignant phenotype has been analyzed by small interfering RNA-induced GPNMB/OA silencing. We found that following GPNMB/OA silencing the migration capability of both DU145 and PC3 cells, evaluated by using in vitro invasivity assay, as well as the metalloproteinases MMP-2 and MMP-9 activity were equally strongly inhibited. By contrast knocking down GPNMB/OA weakly attenuated cell proliferation rate of DU145, an effect that paralleled with an increase number of apoptotic cells. However, PC3 cell growth seems to be not affected by GPNMB/OA. Together, these data reveal that GPNMB/OA acts as a critical molecular mediator promoting the acquisition of the more aggressive, pro-metastatic phenotype distinctive of human DU145 and PC3 cell lines.

Dietary zeolite supplementation reduces oxidative damage and plaque generation in the brain of an Alzheimer's disease mouse model.

AIM: Oxidative stress is considered one of the main events that lead to aging and neurodegeneration. Antioxidant treatments used to counteract oxidative damage have been associated with a wide variety of side effects or at the utmost to be ineffective. The aim of the present study was to investigate the antioxidant property of a natural mineral, the tribomechanically micronized zeolite (MZ). MAIN METHODS: Cell death and oxidative stress were assessed in retinoic acid differentiated SH-SY5Y cells, a neuronal-like cell line, after a pro-oxidant stimulus. In vivo evaluation of antioxidant activity and amyloidogenic processing of beta amyloid have been evaluated in a transgenic model of aging related neurodegeneration, the APPswePS1dE9 transgenic mice (tg mice) after a five-month long period of water supplementation with MZ. KEY FINDINGS: The study showed that 24h of cell pretreatment with MZ (1) protected the cells by radical oxygen species (ROS)-induced cell death and moreover (2) induced a reduction of the mitochondrial ROS production following a pro-oxidant stimulation. Looking for an antioxidant effect of MZ in vivo, we found (3) an increased activity of the endogenous antioxidant enzyme superoxide dismutase (SOD) in the hippocampus of tg mice and (4) a reduction in amyloid levels and plaque load in MZ treated tg mice compared to control tg mice. SIGNIFICANCE: Our results suggest MZ as a novel potential adjuvant in counteracting oxidative stress and plaque accumulation in the field of neurodegenerative diseases.

Targeting Notch pathway induces growth inhibition and differentiation of neuroblastoma cells.

High-risk neuroblastoma is a severe pediatric tumor characterized by poor prognosis. Understanding the molecular mechanisms involved in tumor development and progression is strategic for the improvement of pharmacological therapies. Notch was recently proposed as a pharmacological target for the therapy of several cancers and is emerging as a new neuroblastoma-related molecular pathway. However, the precise role played by Notch in this cancer remains to be studied extensively. Here, we show that Notch activation by the Jagged1 ligand enhances the proliferation of neuroblastoma cells, and we propose the possible use of Notch-blocking γ-secretase inhibitors (GSIs) in neuroblastoma therapy. Two different GSIs, Compound E and DAPT, were tested alone or in combination with 13-cis retinoic acid (RA) on neuroblastoma cell lines. SH-SY5Y and IMR-32 cells were chosen as paradigms of lower and higher malignancy, respectively. Used alone, GSIs induced complete cell growth arrest, promoted neuronal differentiation, and significantly reduced cell motility. The combination of GSIs and 13-cis RA resulted in the enhanced growth inhibition, differentiation, and migration of neuroblastoma cells. In summary, our data suggest that a combination of GSIs with 13-cis RA offers a therapeutic advantage over a single agent, indicating a potential novel therapy for neuroblastoma.

Generation of reactive oxygen species by beta amyloid fibrils and oligomers involves different intra/extracellular pathways.

A neuropathological characteristic of Alzheimer's disease is the extracellular accumulation of amyloid beta peptide (Abeta) in neuritic plaques. Recent evidences suggested that soluble Abeta oligomers are the predominant neurotoxic species for neurons. Thus, considerable attention has been paid to discriminate the cytotoxic pathways of Abeta pre-fibrillar aggregates and mature fibrils. We showed that the mechanisms by which Abeta oligomers and fibrils generated reactive oxygen species differ in terms of site of production and kinetics, suggesting the involvement of different intra/extracellular pathways.

Notch activation induces neurite remodeling and functional modifications in SH-SY5Y neuronal cells.

Notch proteins are definitely recognized as key regulators of the neuronal fate during embryo development, but their function in the adult brain is still largely unknown. We have previously demonstrated that Notch pathway stimulation increases microtubules stability followed by the remodeling of neuronal morphology with neurite varicosities loss, thicker neuritis, and enlarged growth cones. Here we show that the neurite remodeling is a dynamic event, dependent on transcription and translation, and with functional implications. Exposure of differentiated human SH-SY5Y neuroblastoma cells to the Notch ligand Jagged1 induces varicosities loss all along the neurites, accompanied by the redistribution of presynaptic vesicles and the decrease in neurotransmitters release. As evaluated by time lapse digital imaging, dynamic changes in neurite morphology were rapidly reversible and dependent on the activation of the Notch signaling pathway. In fact, it was prevented by the inhibition of the proteolytic gamma-secretase enzyme or the transcription machinery, and was mimicked by the transfection of the intracellular domain of Notch. One hour after treatment with Jagged1, several genes were downregulated. Many of these genes encode proteins that are known to be involved in protein synthesis. These data suggest that in adult neurons, Notch pathway activates a transcriptional program that regulates the equilibrium between varicosities formation and varicosities loss in the neuronal presynaptic compartment involving the expression and redistribution of both structural and functional proteins.

Blockade of the tumor necrosis factor-related apoptosis inducing ligand death receptor DR5 prevents beta-amyloid neurotoxicity.

We originally suggested that inhibition of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) death pathway could be taken into consideration as a potential therapeutic strategy for Alzheimer's disease (AD). However, because the critical role of TRAIL in immune surveillance, the neutralization of TRAIL protein by an antibody to prevent its binding to death receptors is definitely a risky approach. Here, we demonstrated that the blockade of the TRAIL death receptor DR5 with a specific antibody completely prevented amyloid beta peptide (A beta) neurotoxicity in both neuronal cell line and primary cortical neurons. DR5 was demonstrated to be a key factor in TRAIL death pathway. In fact, whereas TRAIL expression was enhanced dose-dependently by concentrations of beta amyloid ranging from 10 nM to 1 microM, only the highest toxic dose of A beta (25 microM) induced the increased expression of DR5 and neuronal cell death. In addition, the increased expression of DR5 receptor after beta amyloid treatment was sustained by p53 transcriptional activity, as demonstrated by the data showing that the p53 inhibitor Pifithrin alpha prevented both beta amyloid-induced DR5 induction and cell death. These data suggest a sequential activation of p53 and DR5 upon beta amyloid exposure. Further insight into the key role of DR5 in AD was suggested by data showing a significant increase of DR5 receptor in cortical slices of AD brain. Thus, these findings may give intracellular TRAIL pathway a role in AD pathophysiology, making DR5 receptor a possible candidate as a pharmacological target.