ABSTRACT
BACKGROUND AND OBJECTIVE: Alterations in gene expressions are often due to epigenetic modifications that can have a significant influence on cancer development, growth, and progression. Lately, histone deacetylase inhibitors (HDACi) such as suberoylanilide hydroxamic acid (SAHA, or vorinostat, MK0683) have been emerging as a new class of drugs with promising therapeutic benefits in controlling cancer growth and metastasis. The small molecule RG7388 (idasanutlin, R05503781) is a newly developed inhibitor that is specific for an oncogene-derived protein called MDM2, which is also in clinical trials for the treatment of various types of cancers. These two drugs have shown the ability to induce p21 expression through distinct mechanisms in MCF-7 and LNCaP cells, which are reported to have wild-type TP53. Our understanding of the molecular mechanism whereby SAHA and RG7388 can induce cell cycle arrest and trigger cell death is still evolving. In this study, we performed experiments to measure the cell cycle arrest effects of SAHA and RG7388 using MCF-7 and LNCaP cells. MATERIALS AND METHODS: The cytotoxicity, cell cycle arrest, and apoptosis/necroptosis effects of the SAHA and RG7388 treatments were assessed using the Trypan Blue dye exclusion (TBDE) method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence assay with DEVD-amc substrate, and immunoblotting methods. RESULTS: The RG7388 treatment was able to induce cell death by elevating p21WAF1/CIP1 through inhibition of MDM2 in LNCaP, but not in MCF-7 cells, even though there was evidence of p53 elevation. Hence, we suspect that there is some level of uncoupling of p53-mediated transcriptional induction of p21WAF1/CIP1 in MCF-7 cells. CONCLUSION: Our results from MCF-7 and LNCaP cells confirmed that SAHA and RG7388 treatments were able to induce cell death via a combination of cell cycle arrest and cytotoxic mechanisms. We speculate that our findings could lead to the development of newer treatments for breast and prostate cancers with drug combinations including HDACi.
Subject(s)
Breast Neoplasms/drug therapy , Cell Cycle Checkpoints/drug effects , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Cyclin-Dependent Kinase Inhibitor p27/metabolism , Histone Deacetylase Inhibitors/pharmacology , Prostatic Neoplasms/drug therapy , Pyrrolidines/pharmacology , Vorinostat/pharmacology , para-Aminobenzoates/pharmacology , Apoptosis/drug effects , Cell Survival/drug effects , Drug Discovery , Female , Histone Deacetylase Inhibitors/therapeutic use , Humans , MCF-7 Cells , Male , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Pyrrolidines/therapeutic use , Tumor Suppressor Protein p53/biosynthesis , Vorinostat/therapeutic use , para-Aminobenzoates/therapeutic useABSTRACT
BACE1, a ß secretase candidate enzyme, initiates the Alzheimer's disease (AD) pathogenesis via amyloid ß (Aß) peptide production serving as a potential therapeutic target. Previous experimental evidence suggested that ginsenosides, a key component of Panax ginseng, are effective against AD. In this study, we implemented a molecular modeling method to reveal the inhibitory action of ginsenosides on BACE1 activity. We selected 12 ginsenosides and performed molecular docking studies to evaluate its interaction with the BACE1 active site, which is essential for inhibition. Further ADMET filtration was applied to find drug-like molecules with a specific ability to cross blood brain barrier (BBB), and to determine toxicity. The BACE1-ginsenosides complex was further subjected to a molecular dynamics simulation to study the stability of the complex and its hydrogen bond interactions. In summary, our findings show ginsenosides CK, F1, Rh1 and Rh2 are potential BACE1 inhibitors from Panax ginseng.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aspartic Acid Endopeptidases/antagonists & inhibitors , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Ginsenosides/chemistry , Ginsenosides/pharmacology , Molecular Docking Simulation , Molecular Dynamics Simulation , Panax/chemistry , Amyloid Precursor Protein Secretases/chemistry , Amyloid Precursor Protein Secretases/metabolism , Aspartic Acid Endopeptidases/chemistry , Aspartic Acid Endopeptidases/metabolism , Catalytic Domain , Drug Stability , Enzyme Inhibitors/metabolism , Ginsenosides/metabolism , Humans , Hydrogen Bonding , ThermodynamicsABSTRACT
It is quite apparent that the incidence of neurodegenerative diseases in both men and women increases in a logarithmic fashion with age and begins to rise much more rapidly after the age of 60. Brain aging is accompanied by structural and functional changes at cellular and tissue levels such as increase in free radical generation, lowered antioxidant defenses, decrease in number of neurons, decrease in the activities of enzymes, (g) decrease in impulse transmission. The present study was aimed to assess the neuromodulatory role of Glutathione monoester (GME) when administered intraperitoneally (12 mg/kg body weight) for 20 days on acetylcholine esterase (AchE) activity, levels of neurotransmitters such as dopamine, serotonin, norepinephrine and rotorod behavioral analysis in discrete brain regions of young and aged male albino Wistar rats. Age-related decrease (p<0.05) in acetylcholine esterase activity, neurotransmitter levels and also decrease in sensorimotor performance was observed. GME administration was effective in restoring these neuronal parameters in aged rat brain regions. Thus GME act as a neuromodulator in discrete brain regions of aged rats.
