Transcriptome Profile Analysis of Triple-Negative Breast Cancer Cells in Response to a Novel Cytostatic Tetrahydroisoquinoline Compared to Paclitaxel

The absence of chemotherapeutic target hormone receptors in breast cancer is descriptive of the commonly known triple-negative breast cancer (TNBC) subtype. TNBC remains one of the most aggressive invasive breast cancers, with the highest mortality rates in African American women. Therefore, new drug therapies are continually being explored. Microtubule-targeting agents such as paclitaxel (Taxol) interfere with microtubules dynamics, induce mitotic arrest, and remain a first-in-class adjunct drug to treat TNBC. Recently, we synthesized a series of small molecules of substituted tetrahydroisoquinolines (THIQs). The lead compound of this series, with the most potent cytostatic effect, was identified as 4-Ethyl-N-(7-hydroxy-3,4-dihydroisoquinolin-2(1H)-yl) benzamide (GM-4-53). In our previous work, GM-4-53 was similar to paclitaxel in its capacity to completely abrogate cell cycle in MDA-MB-231 TNBC cells, with the former not impairing tubulin depolymerization. Given that GM-4-53 is a cytostatic agent, and little is known about its mechanism of action, here, we elucidate differences and similarities to paclitaxel by evaluating whole-transcriptome microarray data in MDA-MB-231 cells. The data obtained show that both drugs were cytostatic at non-toxic concentrations and caused deformed morphological cytoskeletal enlargement in 2D cultures. In 3D cultures, the data show greater core penetration, observed by GM-4-53, than paclitaxel. In concentrations where the drugs entirely blocked the cell cycle, the transcriptome profile of the 48,226 genes analyzed (selection criteria: (p-value, FDR p-value < 0.05, fold change −2< and >2)), paclitaxel evoked 153 differentially expressed genes (DEGs), GM-4-53 evoked 243 DEGs, and, of these changes, 52/153 paclitaxel DEGs were also observed by GM-4-53, constituting a 34% overlap. The 52 DEGS analysis by String database indicates that these changes involve transcripts that influence microtubule spindle formation, chromosome segregation, mitosis/cell cycle, and transforming growth factor-β (TGF-β) signaling. Of interest, both drugs effectively downregulated “inhibitor of DNA binding, dominant negative helix-loop-helix” (ID) transcripts; ID1, ID3 and ID4, and amphiregulin (AREG) and epiregulin (EREG) transcripts, which play a formidable role in cell division. Given the efficient solubility of GM-4-53, its low molecular weight (MW; 296), and capacity to penetrate a small solid tumor mass and effectively block the cell cycle, this drug may have future therapeutic value in treating TNBC or other cancers. Future studies will be required to evaluate this drug in preclinical models.

Whole-transcriptomic Profile of SK-MEL-3 Melanoma Cells Treated with the Histone Deacetylase Inhibitor: Trichostatin A

BACKGROUND

Malignant melanoma cells can rapidly acquire phenotypic properties making them resistant to radiation and mainline chemotherapies such as decarbonize or kinase inhibitors that target RAS-proto-oncogene independent auto-activated mitogen-activated protein kinases (MAPK)/through dual specificity mitogen-activated protein kinase (MEK). Both drug resistance and inherent transition from melanocytic nevi to malignant melanoma involve the overexpression of histone deacetylases (HDACs) and a B-Raf proto-oncogene (BRAF) mutation.

MATERIALS AND METHODS

In this work, the effects of an HDAC class I and II inhibitor trichostatin A (TSA) on the whole transcriptome of SK-MEL-3 cells carrying a BRAF mutation was examined.

RESULTS

The data obtained show that TSA was an extremely potent HDAC inhibitor within SK-MEL-3 nuclear lysates, where TSA was then optimized for appropriate sub-lethal concentrations for in vitro testing. The whole-transcriptome profile shows a basic phenotype dominance in the SK-MEL-3 cell line for i) synthesis of melanin, ii) phagosome acidification, iii) ATP hydrolysis-coupled proton pumps and iv) iron transport systems. While TSA did not affect the aforementioned major systems, it evoked a dramatic change to the transcriptome: reflected by a down-regulation of 810 transcripts and up-regulation of 833, with fold-change from -15.27 to +31.1 FC (p<0.00001). Largest differentials were found for the following transcripts: Up-regulated: Tetraspanin 13 (TSPAN13), serpin family i member 1 (SERPINI1), ATPase Na+/K+ transporting subunit beta 2 (ATP1B2), nicotinamide nucleotide adenylyl transferase 2 (NMNAT2), platelet-derived growth factor receptor-like (PDGFRL), cytochrome P450 family 1 subfamily A member 1 (CYP1A1), prostate androgen-regulated mucin-like protein 1 (PARM1), secretogranin II (SCG2), SYT11 (synaptotagmin 11), rhophilin associated tail protein 1 like (ROPN1L); down-regulated: polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3), carbonic anhydrase 14 (CAXIV), BCL2-related protein A1 (BCL2A1), protein kinase C delta (PRKCD), transient receptor potential cation channel subfamily M member 1 (TRPM1), ubiquitin associated protein 1 like (UBAP1L), glutathione peroxidase 8 (GPX8), interleukin 16 (IL16), tumor protein p53 (TP53), and serpin family H member 1 (SERPINH1). There was no change to any of the HDAC transcripts (class I, II and IV), the sirtuin HDAC family (1-6) or the BRAF proto-oncogene v 599 transcripts. However, the data showed that TSA down-regulated influential transcripts that drive the BRAF-extracellular signal-regulated kinase (ERK)1/2 oncogenic pathway (namely PRKCD and MYC proto-oncogene which negatively affected the cell-cycle distribution. Mitotic inhibition was corroborated by functional pathway analysis and flow cytometry confirming halt at the G₂ phase, occurring in the absence of toxicity.

CONCLUSION

TSA does not alter HDAC transcripts nor BRAF itself, but down-regulates critical components of the MAPK/MEK/BRAF oncogenic pathway, initiating a mitotic arrest.

Transcriptomic Profiling of MDA-MB-231 Cells Exposed to Boswellia Serrata and 3-O-Acetyl-B-Boswellic Acid; ER/UPR Mediated Programmed Cell Death

BACKGROUND/AIM

Triple-negative breast cancer (TNBC) is characterized by the absence of hormone receptors (estrogen, progesterone and human epidermal growth factor receptor-2) and a relatively poor prognosis due to inefficacy of hormone receptor-based chemotherapies. It is imperative that we continue to explore natural products with potential to impede growth and metastasis of TNBC. In this study, we screened over 1,000 natural products for capacity to induce cell death in TNBC (MDA-MB -231) cells.

MATERIALS AND METHODS

Frankincense (Boswellia serrata extract (BSE)) and 3-O-Acetyl-β-boswellic acid (3-OAβBA) were relatively potent, findings that corroborate the body of existing literature. The effects of BSE and 3-OAβBA on genetic parameters in MDA-MB-231 cells were evaluated by examining whole-transcriptomic influence on mRNAs, long intergenic non-coding RNA transcripts (lincRNA) and non-coding miRNAs.

RESULTS

Bio-statistical analysis demarcates the primary effect of both BSE/3-OAβBA on the up-regulation of PERK (protein kinase RNA-like endoplasmic reticulum kinase)- endoplasmic reticulum (ER)/unfolded protein response (UPR) pathways that are closely tied to activated programmed cell death (APCD). Global profiling confirms concomitant effects of BSE/3-OAβBA on upwardly expressed ER/URP APCD key components PERK (EIF2AK3), XBP1, C/EBP homologous protein transcription factor (CHOP), ATF3 and DDIT3,4/DNA-damage-inducible transcript 3,4 (GADD34). Further, BSE and/or 3-OAβBA significantly down-regulated oncogenes (OG) which, heretofore, lack functional pathway mapping, but are capable of driving epithelial-mesenchymal transition (EMT), cell survival, proliferation, metastasis and drug resistance. Among these are cell migration-inducing protein hyaluronan binding (CEMIP) [-7.22]; transglutaminase 2 [-4.96], SRY box 9 (SOX9) [-4.09], inhibitor of DNA binding 1, dominant negative helix-loop-helix protein (ID1) [-6.56]; and endothelin 1 (EDN1, [-5.06]). Likewise, in the opposite manner, BSE and/or 3-OAβBA induced the robust overexpression of tumor suppressor genes (TSGs), including: glutathione-depleting ChaC glutathione-specific gamma-glutamylcyclotransferase 1 (CHAC1) [+21.67]; the mTOR inhibitors - sestrin 2 (SESN2) [+16.4] Tribbles homolog 3 (TRIB3) [+6.2], homocysteine-inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1 (HERPUD1) [+12.01]; and cystathionine gamma-lyase (CTH) [+11.12].

CONCLUSION

The anti-cancer effects of the historically used frankincense sap (BSE) appear to involve major impact on the ER/UPR response, concomitant to effecting multiple targets counter to the growth, proliferation and metastasis of TNBC cancer cells. The microarray data are available at Expression Omnibus GEO Series accession number GSE102891.

Effects of Sepantronium Bromide (YM-155) on the Whole Transcriptome of MDA-MB-231 Cells: Highlight on Impaired ATR/ATM Fanconi Anemia DNA Damage Response

Sepantronium bromide (YM-155) is believed to elicit apoptosis and mitotic arrest in tumor cells by reducing (BIRC5, survivin) mRNA. In this study, we monitored changes in survivin mRNA and protein after treating MDA-MB-231 cells with YM-155 concurrent with evaluation of whole transcriptomic (WT) mRNA and long intergenic non-coding RNA at 2 time points: 8 h sub-lethal (83 ng/mL) and 20 h at the LC50 (14.6 ng/mL). The data show a tight association between cell death and the precipitating loss of survivin protein and mRNA (-2.67 fold-change (FC), p<0.001) at 20 h, questioning if the decline in survivin is attributed to cell death or drug impact. The meager loss of survivin mRNA was overshadowed by enormous differential change to the WT in both magnitude and significance for over 2000 differentially up/down-regulated transcripts: (+22 FC to -12 FC, p<0.001). The data show YM-155 to up-regulate transcripts in control of circadian rhythm (NOCT, PER, BHLHe40, NFIL3), tumor suppression (SIK1, FOSB), histone methylation (KDM6B) and negative feedback of NF-kappa B signaling (TNFAIP3). Down-regulated transcripts by YM-155 include glucuronidase (GUSBP3), numerous micro-RNAs, DNA damage repair elements (CENPI, POLQ, RAD54B) and the most affected system was the ataxia-telangiectasia mutated (ATM)/Fanconi anemia E3 monoubiquitin ligase core complexes (FANC transcripts - A/B/E/F/G/M), FANC2, FANCI, BRCA1, BRCA2, RAD51, PALB2 gene and ATR (ATM- and Rad3-Related) pathway. In conclusion, these findings suggest that a primary target of YM-155 is the loss of replicative DNA repair systems.

Synthesis of "neoprofen", a rigidified analogue of ibuprofen, exemplifying synthetic methodology for altering the 3-D topology of pharmaceutical substances

3,3-Dimethylcyclopentanes (neopentylenes) are ubiquitous in Nature but largely absent from synthetic pharmaceutical libraries. Neopentylenes define a hydrophobic and rigid 3-D topology with distinct molecular pharmacology, as exemplified here with two neopentylene-fused analogues of the synthetic anti-inflammatory drug, ibuprofen.

Stable shRNA Silencing of Lactate Dehydrogenase A (LDHA) in Human MDA-MB-231 Breast Cancer Cells Fails to Alter Lactic Acid Production, Glycolytic Activity, ATP or Survival

BACKGROUND

In the US, African Americans have a high death rate from triple-negative breast cancer (TNBC), characterized by lack of hormone receptors (ER, PR, HER2/ERRB2) which are otherwise valuable targets of chemotherapy. There is a need to identify novel targets that negatively impact TNBC tumorigenesis. TNBCs release an abundance of lactic acid, under normoxic, hypoxic and hyperoxic conditions; this referred to as the Warburg effect. Accumulated lactic acid sustains peri-cellular acidity which propels metastatic invasion and malignant aggressive transformation. The source of lactic acid is believed to be via conversion of pyruvate by lactate dehydrogenase (LDH) in the last step of glycolysis, with most studies focusing on the LDHA isoform.

MATERIALS AND METHODS

In this study, LDHA was silenced using long-term MISSION® shRNA lentivirus in human breast cancer MDA-MB-231 cells. Down-regulation of LDHA transcription and protein expression was confirmed by western blot, immunocytochemistry and qPCR. A number of parameters were measured in fully viable vector controls versus knock-down (KD) clones, including levels of lactic acid produced, glucose consumed, ATP and basic metabolic rates.

RESULTS

The data show that lentivirus V-165 generated a knock-down clone most effective in reducing both gene and protein levels to less than 1% of vector controls. Stable KD showed absolutely no changes in cell viability, lactic acid production, ATP, glucose consumption or basic metabolic rate. Given the complete absence of impact on any observed parameter by LDH-A KD and this being somewhat contrary to findings in the literature, further analysis was required to determine why. Whole-transcriptome analytic profile on MDA-MB-231 for LDH subtypes using Agilent Human Genome 4×44k microarrays, where the data show the following component breakdown. Transcripts: 30.47 % LDHA, 69.36% LDHB, 0.12% LDHC and 0.05% LDHD.

CONCLUSION

These findings underscore the importance of alternative isoforms of LDH in cancer cells to produce lactic acid, when LDHA is silenced or inhibited. LDHA silencing alone is not effective in hampering or inducing changes in survival, metabolism or lactic acid produced in a cell line with high concentrations of LDHB. Future research will be required to confirm effects of dual LDHA/B knockdown and further confirm that the sole source of lactic acid produced occurs through LDH (all isoforms) in breast cancer cells.

HTP Nutraceutical Screening for Histone Deacetylase Inhibitors and Effects of HDACis on Tumor-suppressing miRNAs by Trichostatin A and Grapeseed (Vitis vinifera) in HeLa cells

BACKGROUND/AIM

Aggressive tumor malignancies are a consequence of delayed diagnosis, epigenetic/phenotype changes and chemo-radiation resistance. Histone deacetylases (HDACs) are a major epigenetic regulator of transcriptional repression, which are highly overexpressed in advanced malignancy. While original chemotherapy drugs were modeled after phytochemicals elucidated by botanical screenings, HDAC inhibitors (HDACi) such as apicidin, trichostatin A (TSA) and butyrate were discovered as products of fungus and microbes, in particular, gut microbiota. Therefore, a persistent question remains as to the inherent existence of HDACis in raw undigested dietary plant material. In this study, we conduct a high-throughput (HTP) screening of ~1,600 non-fermented commonly used nutraceuticals (spices, herbs, teas, vegetables, fruits, seeds, rinds etc.) at (<600 μg/ml) and food-based polyphenolics (<240 μg/ml) for evidence of HDAC activity inhibition in nuclear HeLa cell lysates.

MATERIALS AND METHODS

Human HDAC kinetic validation was performed using a standard fluorometric activity assay, followed by an enzymatic-linked immuno-captured ELISA. Both methods were verified using HDACi panel drugs: TSA, apicidin, suberohydroxamic acid, M344, CL-994, valproic acid and sodium phenylbutyrate. The HTP screening was then conducted, followed by a study comparing biological effects of HDACis in HeLa cells, including analysis of whole-transcriptome non-coding RNAs using Affymetrix miRNA 4.1-panel arrays.

RESULTS

The HTP screening results confirmed 44/1600 as potential HDACis to which 31 were further eliminated as false-positives. Methodological challenges/concerns are addressed regarding plant product false-positives that arise from the signal reduction of commercial lysine development reagents. Only 13 HDACis were found having an IC₅₀ under <200 μg/ml: Grapeseed extract (Vitis vinifera), Great burnet root (Sanguisorba Officinalis), Babul (Acacia arabica), Chinese gallnut (Melaphis chinensis), Konaberry extract (Coffea arabica), Uva Ursi (Arctostaphylos uva ursi), Green tea (Camellia sinensis), Meadowsweet (Filipendula ulmaria), Sassafras (Sassafras officinale), Turkey rhubarb (Rheum palmatum), epigallocatechin gallate (EGCG), gossypol and gallic acid. Next, we investigate the biological consequence of HDACi panel drugs in HeLa cells, where the data suggest predominant effects are anti-mitotic rather than cytotoxic. Lastly, differential effects of TSA vs. GSE at sub-lethal concentrations tested on HeLa cells show 6,631 miRNAs expressed in resting cells, 35 significantly up-regulated (TSA) and 81 up-regulated (GSE), with several miRNAs overlapping in the upward direction by both GSE and TSA (e.g. hsa-miR-23b-5p, hsa-miR-27b-5p, hsa-miR-1180-3p, hsa-miR-6880-5p and hsa-mir-943). Using DIANA miRNA online tools, it was determined that GSE and TSA simultaneously cause overexpression of similar miRNAs predicted to destroy the following influential oncogenes: NFkB, NRAS, KRAS, HRAS, MYC, TGFBR1, E2F1, E2F2, BCL21, CDKN1A, CDK6, HIF1a, and VEGFA.

CONCLUSION

The data from this study show that plant- based HDACis are relatively rare, and can elicit a similar pattern to TSA in up-regulating miRNAs involved with tumor suppression of HeLa cervical carcinoma.

Natural product HTP screening for attenuation of cytokine-induced neutrophil chemo attractants (CINCs) and NO2- in LPS/IFNγ activated glioma cells

Chronic and acute central nervous system (CNS) inflammation are contributors toward neurological injury associated with head trauma, stroke, infection, Parkinsons or Alzheimers disease. CNS inflammatory illnesses can also contribute toward risk of developing glioblastoma multiforme (GBM). With growing public interest in complementary and alternative medicines (CAMs), we conduct a high throughput (HTP) screening of >1400 natural herbs, plants and over the counter (OTC) products for anti-inflammatory effects on lipopolysaccharide (LPS)/interferon gamma (IFNγ) activated C6 glioma cells. Validation studies were performed showing a pro-inflammatory profile of [LPS 3 µg/ml/ IFNγ 3 ng/ml] consistent with greater release [>8.5 fold] of MCP-1, NO2-, cytokine-induced neutrophil chemo-attractants (CINC) 1, CINC 2a and CINC3. The data show no changes to the following, IL-13, TNF-a, fracktaline, leptin, LIX, GM-CSF, ICAM1, L-Selectin, activin A, agrin, IL-1α, MIP-3a, B72/CD86, NGF, IL-1b, MMP-8, IL-1 R6, PDGF-AA, IL-2, IL-4, prolactin R, RAGE, IL-6, Thymus Chemokine-1, CNTF,IL-10 or TIMP-1. A HTP screening was conducted, where we employ an in vitro efficacy index (iEI) defined as the ratio of toxicity (LC₅₀)/anti-inflammatory potency (IC₅₀). The iEI was precautionary to ensure biological effects were occurring in fully viable cells (ratio > 3.8) independent of toxicity. Using NO2- as a guideline molecule, the data show that 1.77% (25 of 1410 tested) had anti-inflammatory effects with iEI ratios >3.8 and IC₅₀s <250µg/ml. These include reference drugs (hydrocortisone, dexamethasone N6-(1-iminoethyl)-l-lysine and NSAIDS: diclofenac, tolfenamic acid), a histone deacetylase inhibitor (apicidin) and the following natural products; Ashwaganda (Withania somnifera), Elecampagne Root (Inula helenium), Feverfew (Tanacetum parthenium), Green Tea (Camellia sinensis), Turmeric Root (Curcuma longa) Ganthoda (Valeriana wallichii), Tansy (Tanacetum vulgare), Maddar Root (Rubia tinctoria), Red Sandle wood (Pterocarpus santalinus), Bay Leaf (Laurus nobilis, Lauraceae), quercetin, cardamonin, fisetin, EGCG, biochanin A, galangin, apigenin and curcumin. The herb with the largest iEI was Ashwaganda where the IC₅₀/LC₅₀ was 11.1/>1750.0μg/ml, and the compound with the greatest iEI was quercetin where the IC₅₀/LC₅₀ was 10.0/>363.6μg/ml. These substances also downregulate the production of iNOS expression and attenuate CINC-3 release. In summary, this HTP screening provides guideline information about the efficacy of natural products that could prevent inflammatory processes associated with neurodegenerative disease and aggressive glioma tumor growth.

Natural product HTP screening for antibacterial (E.coli 0157:H7) and anti-inflammatory agents in (LPS from E. coli O111:B4) activated macrophages and microglial cells; focus on sepsis

Background

Acute systemic inflammatory response syndrome arising from infection can lead to multiple organ failure and death, with greater susceptibility occurring in immunocompromised individuals. Moreover, sub-acute chronic inflammation is a contributor to the pathology of diverse degenerative diseases (Parkinson’s disease, Alzheimer’s disease and arthritis). Given the known limitations in Western medicine to treat a broad range of inflammatory related illness as well as the emergence of antibiotic resistance, there is a renewed interest in complementary and alternative medicines (CAMs) to achieve these means.

Methods

A high throughput (HTP) screening of >1400 commonly sold natural products (bulk herbs, cooking spices, teas, leaves, supplement components, nutraceutical food components, fruit and vegetables, rinds, seeds, polyphenolics etc.) was conducted to elucidate anti-inflammatory substances in lipopolysaccharide (LPS) (E. coli serotype O111:B4) monocytes: RAW 264.7 macrophages [peripheral], BV-2 microglia [brain]) relative to hydrocortisone, dexamethasone and L-N6-(1Iminoethyl)lysine (L-NIL). HTP evaluation was also carried out for lethal kill curves against E.coli 0157:H7 1x10⁶ CFU/mL relative to penicillin. Validation studies were performed to assess cytokine profiling using antibody arrays. Findings were corroborated by independent ELISAs and NO2–/iNOS expression quantified using the Griess Reagent and immunocytochemistry, respectively. For robust screening, we developed an in-vitro efficacy paradigm to ensure anti-inflammatory parameters were observed independent of cytotoxicity. This caution was taken given that many plants exert tumoricidal and anti-inflammatory effects at close range through similar signaling pathways, which could lead to false positives.

Results

The data show that activated BV-2 microglia cells (+ LPS 1μg/ml) release >10-fold greater IL-6, MIP1/2, RANTES and nitric oxide (NO2–), where RAW 264.7 macrophages (+ LPS 1μg/ml) produced > 10-fold rise in sTNFR2, MCP-1, IL-6, GCSF, RANTES and NO2–. Data validation studies establish hydrocortisone and dexamethasone as suppressing multiple pro-inflammatory processes, where L-NIL suppressed NO2–, but had no effect on iNOS expression or IL-6. The screening results demonstrate relative few valid hits with anti-inflammatory effects at < 250μg/ml for the following: Bay Leaf (Laurus nobilis), Elecampagne Root (Inula helenium), Tansy (Tanacetum vulgare),Yerba (Eriodictyon californicum) and Centipeda (Centipeda minima), Ashwagandha (Withania somnifera), Feverfew (Tanacetum parthenium), Rosemary (Rosmarinus officinalis), Turmeric Root (Curcuma Longa), Osha Root (Ligusticum porteri), Green Tea (Camellia sinensis) and constituents: cardamonin, apigenin, quercetin, biochanin A, eupatorin, (-)-epigallocatechin gallate (EGCG) and butein. Natural products lethal against [E. coli 0157:H7] where the LC₅₀ < 100 μg/ml included bioactive silver hydrosol-Argentyn 23, green tea (its constituents EGCG > Polyphenon 60 > (-)-Gallocatechin > Epicatechin > (+)-Catechin), Grapeseed Extract (Vitis vinifera), Chinese Gallnut (its constituents gallic acid > caffeic acid) and gallic acid containing plants such as Babul Chall Bark (Acacia Arabica), Arjun (Terminalia Arjuna) and Bayberry Root Bark (Morella Cerifera).

Conclusions

These findings emphasize and validate the previous work of others and identify the most effective CAM anti-inflammatory, antibacterial compounds using these models. Future work will be required to evaluate potential combination strategies for long-term use to prevent chronic inflammation and possibly lower the risk of sepsis in immunocompromised at risk populations.

Anti-inflammatory effects of thymoquinone in activated BV-2 microglial cells

Thymoquinone (TQ), the main pharmacological active ingredient within the black cumin seed (Nigella sativa) is believed to be responsible for the therapeutic effects on chronic inflammatory conditions such as arthritis, asthma and neurodegeneration. In this study, we evaluated the potential anti-inflammatory role of TQ in lipopolysaccharide (LPS)-stimulated BV-2 murine microglia cells. The results obtained indicate that TQ was effective in reducing NO2(-) with an IC50 of 5.04μM, relative to selective iNOS inhibitor LNIL-l-N6-(1-iminoethyl)lysine (IC50 4.09μM). TQ mediated reduction in NO2(-) was found to parallel the decline of iNOS protein expression as confirmed by immunocytochemistry. In addition, we evaluated the anti-inflammatory effects of TQ on ninety-six (96) cytokines using a RayBio AAM-CYT-3 and 4 cytokine antibody protein array. Data obtained establish a baseline protein expression profile characteristic of resting BV-2 cells in the order of osteopontin>MIP-1alpha>MIP-1g>IGF-1 and MCP-I. In the presence of LPS [1ug/ml], activated BV-2 cells produced a sharp rise in specific pro-inflammatory cytokines/chemokine's IL-6, IL-12p40/70, CCL12 /MCP-5, CCL2/MCP-1, and G-CSF which were attenuated by the addition of TQ (10μM). The TQ mediated attenuation of MCP-5, MCP-1 and IL-6 protein in supernatants from activated BV-2 cells were corroborated by independent ELISA. Moreover, the data obtained from the RT(2) PCR demonstrated a similar pattern where the LPS mediated elevation of mRNA for IL-6, CCL12/MCP-5, CCL2/MCP-1 were significantly attenuated by TQ (10μM). Also, in this study, consistent data were obtained for both protein antibody array densitometry and ELISA assays. In addition, TQ was found to reduce LPS mediated elevation in gene expression of Cxcl10 and a number of other cytokines in the panel. These findings demonstrate the significant anti-inflammatory properties of TQ in LPS activated microglial cells. Therefore, the obtained results might indicate the usefulness of TQ in delaying the onset of inflammation-mediated neurodegenerative disorders involving activated microglia cells.

The effect of silibinin in enhancing toxicity of temozolomide and etoposide in p53 and PTEN-mutated resistant glioma cell lines

Glioblastoma multiforme (GBM) is an intractable brain tumor, associated with poor prognosis and low survival rate. Combination therapy such as surgery, radiotherapy and temozolomide is considered standard in overcoming this aggressive cancer, despite poor prognosis. There is a need to identify potential agents, which may augment the chemotherapeutic effects of standard drugs such as temozolomide. In this project, we evaluated the effects of silibinin, a natural plant component of milk thistle seeds, to potentiate toxic effects of chemotherapy drugs such as temozolomide, etoposide and irinotecan on LN229, U87 and A172 (P53 and phosphatase and tensin homolog (PTEN) -tumor suppressor-mutated) glioma cell lines. Data from this work suggest that silibinin was effective in potentiating the cytotoxic efficacy of temozolomide in LN229, U87 and A172 cells. While silibinin reduced survivin protein expression only in LN229 cells, its ability to potentiate cytotoxicity of chemo therapy drugs occurred irrespective of survivin protein levels. The data also demonstrated that silibinin potentiated the effect of etoposide and but not irinotecan in LN229 cells. Future research will be required to evaluate the in vivo efficacy of silibinin to delineate its mechanism of action and its ability to cross the blood-brain barrier.

Epigenetics and nutritional environmental signals

All terrestrial life is influenced by multi-directional flows of information about its environment, enabling malleable phenotypic change through signals, chemical processes, or various forms of energy that facilitate acclimatization. Billions of biological co-inhabitants of the earth, including all plants and animals, collectively make up a genetic/epigenetic ecosystem by which adaptation/survival (inputs and outputs) are highly interdependent on one another. As an ecosystem, the solar system, rotation of the planets, changes in sunlight, and gravitational pull influence cyclic epigenetic transitions and chromatin remodeling that constitute biological circadian rhythms controlling senescence. In humans, adverse environmental conditions such as poverty, stress, alcohol, malnutrition, exposure to pollutants generated from industrialization, man-made chemicals, and use of synthetic drugs can lead to maladaptive epigenetic-related illnesses with disease-specific genes being atypically activated or silenced. Nutrition and dietary practices are one of the largest facets in epigenetic-related metabolism, where specific "epi-nutrients" can stabilize the genome, given established roles in DNA methylation, histone modification, and chromatin remodeling. Moreover, food-based "epi-bioactive" constituents may reverse maladaptive epigenetic patterns, not only prior to conception and during fetal/early postnatal development but also through adulthood. In summary, in contrast to a static genomic DNA structure, epigenetic changes are potentially reversible, raising the hope for therapeutic and/or dietary interventions that can reverse deleterious epigenetic programing as a means to prevent or treat major illnesses.

Basic concepts of epigenetics: impact of environmental signals on gene expression

Through epigenetic modifications, specific long-term phenotypic consequences can arise from environmental influence on slowly evolving genomic DNA. Heritable epigenetic information regulates nucleosomal arrangement around DNA and determines patterns of gene silencing or active transcription. One of the greatest challenges in the study of epigenetics as it relates to disease is the enormous diversity of proteins, histone modifications and DNA methylation patterns associated with each unique maladaptive phenotype. This is further complicated by a limitless combination of environmental cues that could alter the epigenome of specific cell types, tissues, organs and systems. In addition, complexities arise from the interpretation of studies describing analogous but not identical processes in flies, plants, worms, yeast, ciliated protozoans, tumor cells and mammals. This review integrates fundamental basic concepts of epigenetics with specific focus on how the epigenetic machinery interacts and operates in continuity to silence or activate gene expression. Topics covered include the connection between DNA methylation, methyl-CpG-binding proteins, transcriptional repression complexes, histone residues, histone modifications that mediate gene repression or relaxation, histone core variant stability, H1 histone linker flexibility, FACT complex, nucleosomal remodeling complexes, HP1 and nuclear lamins.

Pericellular pH homeostasis is a primary function of the Warburg effect: inversion of metabolic systems to control lactate steady state in tumor cells

The Warburg effect describes a heightened propensity of tumor cells to produce lactic acid in the presence or absence of O(2) . A generally held notion is that the Warburg effect is related to energy. Using whole-genome, proteomic MALDI-TOF-MS and metabolite analysis, we investigated the Warburg effect in malignant neuroblastoma N2a cells. The findings show that the Warburg effect serves a functional role in regulating acidic pericellular pH (pHe), which is mediated by metabolic inversion or a fluctuating dominance between glycolytic-rate substrate level phosphorylation (SLP) and mitochondrial (mt) oxidative phosphorylation (OXPHOS) to control lactic acid production. The results also show that an alkaline pHe caused an elevation in SLP/OXPHOS ratio (approximately 98% SLP/OXPHOS); while the ratio was approximately 56% at neutral pHe and approximately 93% in acidic pHe. Acidic pHe paralleled greater expression of mitochondrial biogenesis and OXPHOS genes, such as complex III-V (Uqcr10, Atp5 and Cox7c), mt Fmc1, Romo1, Tmem 173, Tomm6, aldehyde dehydrogenase, mt Sod2 mt biogenesis component PPAR-γ co-activator 1 adjunct to loss of mt fission (Mff). Moreover, acidic pHe corresponded to metabolic efficiency evidenced by a rise in mTOR nutrient sensor GβL, its downstream target (Eif4ebp1), insulin modulators (Trib3 and Fetub) and loss of catabolic (Hadhb, Bdh1 and Pygl)/glycolytic processes (aldolase C, pyruvate kinase, Nampt and aldose-reductase). In contrast, alkaline pHe initiated loss of mitofusin 2, complex II-IV (Sdhaf1, Uqcrq, Cox4i2 and Aldh1l2), aconitase, mitochondrial carrier triple repeat 1 and mt biosynthetic (Coq2, Coq5 and Coq9). In conclusion, the Warburg effect might serve as a negative feedback loop that regulates the pHe toward a broad acidic range by altering lactic acid production through inversion of metabolic systems. These effects were independent of changes in O(2) concentration or glucose supply.

The biochemical and cellular basis for nutraceutical strategies to attenuate neurodegeneration in Parkinson's disease

Future therapeutic intervention that could effectively decelerate the rate of degeneration within the substantia nigra pars compacta (SNc) could add years of mobility and reduce morbidity associated with Parkinson’s disease (PD). Neurodegenerative decline associated with PD is distinguished by extensive damage to SNc dopaminergic (DAergic) neurons and decay of the striatal tract. While genetic mutations or environmental toxins can precipitate pathology, progressive degenerative succession involves a gradual decline in DA neurotransmission/synaptic uptake, impaired oxidative glucose consumption, a rise in striatal lactate and chronic inflammation. Nutraceuticals play a fundamental role in energy metabolism and signaling transduction pathways that control neurotransmission and inflammation. However, the use of nutritional supplements to slow the progression of PD has met with considerable challenge and has thus far proven unsuccessful. This review re-examines precipitating factors and insults involved in PD and how nutraceuticals can affect each of these biological targets. Discussed are disease dynamics (Sections 1 and 2) and natural substances, vitamins and minerals that could impact disease processes (Section 3). Topics include nutritional influences on α-synuclein aggregation, ubiquitin proteasome function, mTOR signaling/lysosomal-autophagy, energy failure, faulty catecholamine trafficking, DA oxidation, synthesis of toxic DA-quinones, o-semiquinones, benzothiazolines, hyperhomocyseinemia, methylation, inflammation and irreversible oxidation of neuromelanin. In summary, it is clear that future research will be required to consider the multi-faceted nature of this disease and re-examine how and why the use of nutritional multi-vitamin-mineral and plant-based combinations could be used to slow the progression of PD, if possible.

In vitro screening of tumoricidal properties of international medicinal herbs: part II

With growing use of anticancer complementary and alternative medicines (CAMs) worldwide, there is a need to assess and screen commercially available natural products for relative tumoricidal properties under standard experimental conditions. In the current study, we screened and ranked 264 traditional Chinese and Egyptian herbal medicines for tumoricidal potency against malignant neuroblastoma in vitro. The data obtained show that tumoricidal potencies of plants were randomly dispersed throughout similar orders, families and genera under the Division: Magnoliophyta, class: Magnoliopsida, subclasses: Asteridae, Caryophyllidae, Dilleniidae, Hamamelididae, Magnoliidae and Rosidae. The most potent plant extracts (LC₅₀ < 0.08 mg/ml) were prepared from gromwell root also known as 'Hong Tiao Zi Cao' (Lithospermum Erythrorhizon) Family (Boraginaceae) > beth root (Trillium Pendulum), Family (Liliaceae) and galbanum (Ferula Galbaniflua), Family (Apiaceae). Gromwell root is traditionally used in the preparation of Chinese medicinal tea. In addition, galbanum was highly regarded for its sacred and medicinal value according to ancient texts and the bible. Future research will be required to isolate and identify chemical constituents within these plants which are responsible for tumoricidal effects.

Variable toxicological response to the loss of OXPHOS through 1-methyl-4-phenylpyridinium-induced mitochondrial damage and anoxia in diverse neural immortal cell lines

Immortal cell lines are used to investigate various aspects of neurodegeneration. These cells display high glycolytic turnover rate and produce an abundant amounts of lactate. Our previous studies indicate that these cells survive the loss of mitochondrial oxidative phosphorylation (OXPHOS) with ample glucose supply. In the current study, we investigate if cell type (w/variation in basal metabolic rate (MR)), can alter glucose utilization patterns which in turn may affect LC(50) for the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP(+)) in various cell lines. The data obtained indicate that cell lines MRs examined were generally consistent with the average of species adult body weight where mouse N-2A > rat-PC-12 > human SH-SY5Y. A higher MR was associated with accelerated utilization of glucose and earlier cell death with MPP(+): LC(50) mouse = 294 µM, rat = 695 µM, and human = 5.25 mM at 24 h. Cell death appears to be a function of the velocity by which glucose disappears, leading to the failure of glycolysis and subsequent halt of energy production. Similar effects were also observed at higher plating densities where the demand for glucose is amplified. A time-lapse study of MPP(+) toxicity (0-36 h) in N-2A cells indicates that an anaerobic shift occurs as early as 2 h (evidenced by a rise in lactate), followed by a descent in glucose concentrations at 4 h and exhaustion of glucose supplies at 22 h which was associated with the first detectable sign of cell death. It was also noted that MPP(+) toxicity was not associated with the generation of reactive oxygen species (O (2) (-) , H(2)0(2), and NO(2)) and was not attenuated by adding catalase or superoxide dismutase to the media. On the other hand, MPP(+) toxicity was reversed by providing additional supply of glucose, pyruvate ± mitochondrial monocarboxylate transporter blocker (α-cyano-4-HCA), or pyruvate ± pyruvate dehydrogenase inhibitor (octanoyl-CoA), suggesting that the exclusive anaerobic survival compensates for the loss of OXPHOS by MPP(+). To examine if neuroblastoma were capable of surviving the deprivation of O(2) for 24 h, a range of hypoxia to anoxia was established with various concentrations of dithionite. The data suggest that cell lines examined continue to thrive when incubated with high-glucose media (25 mM). In summary, vulnerability of immortal neuroblastoma cell lines to MPP(+) toxicity is dependent upon glucose concentrations within the media and cell MR, which indirectly dominates the velocity of glucose use and its end point disappearance, leading to cell death by ergogenic failure.

Evaluation of endogenous acidic metabolic products associated with carbohydrate metabolism in tumor cells

Tumor cells have a high tolerance for acidic and hypoxic microenvironments, also producing abundant lactic acid through accelerated glycolysis in the presence or absence of O(2). While the accumulation of lactate is thought to be a major contributor to the reduction of pH-circumscribing aggressive tumors, it is not known if other endogenous metabolic products contribute this acidity. Furthermore, anaerobic metabolism in cancer cells bears similarity to homo-fermentative lactic acid bacteria, however very little is known about an alternative pathway that may drive adenosine triphosphate (ATP) production independent of glycolysis. In this study, we quantify over 40 end-products (amines, acids, alcohols, aldehydes, or ketones) produced by malignant neuroblastoma under accelerated glycolysis (+glucose (GLU) supply 1-10 mM) +/- mitochondrial toxin; 1-methyl-4-phenylpyridinium (MPP(+)) to abate aerobic respiration to delineate differences between anaerobic vs. aerobic cell required metabolic pathways. The data show that an acceleration of anaerobic glycolysis prompts an expected reduction in extracellular pH (pH(ex)) from neutral to 6.7 +/- 0.006. Diverse metabolic acids associated with this drop in acidity were quantified by ionic exchange liquid chromatography (LC), showing concomitant rise in lactate (Ctrls 7.5 +/- 0.5 mM; +GLU 12.35 +/- 1.3 mM; +GLU + MPP 18.1 +/- 1.8 mM), acetate (Ctrl 0.84 +/- 0.13 mM: +GLU 1.3 +/- 0.15 mM; +GLU + MPP 2.7 +/- 0.4 mM), fumarate, and a-ketoglutarate (<10 microM) while a range of other metabolic organic acids remained undetected. Amino acids quantified by o-phthalaldehyde precolumn derivatization/electrochemical detection-LC show accumulation of L: -alanine (1.6 +/- .052 mM), L: -glutamate (285 +/- 9.7 microM), L: -asparagine (202 +/- 2.1 microM), and L: -aspartate (84.2 +/- 4.9 microM) produced during routine metabolism, while other amino acids remain undetected. In contrast, the data show no evidence for accumulation of acetaldehyde, aldehydes, or ketones (Purpald/2,4-dinitrophenylhydrazine-Brady's reagent), acetoin (Voges-Proskauer test), or alcohols (NAD(+)-linked alcohol dehydrogenase). In conclusion, these results provide preliminary evidence to suggest the existence of an active pyruvate-alanine transaminase or phosphotransacetylase/acetyl-CoA synthetase pathway to be involved with anaerobic energy metabolism of cancer cells.

In vitro screening for the tumoricidal properties of international medicinal herbs

There is growing use of anticancer complementary and alternative medicines (CAMs) worldwide. The purpose of the current study is to assess a sizeable variety of natural and plant sources of diverse origin, to ascertain prospective research directives for cancer treatment and potential new chemotherapy drug sources. In this study, 374 natural extracts (10 microg/mL-5 mg/mL) were evaluated for dose-dependent tumoricidal effects using immortal neuroblastoma of spontaneous malignant origin. The findings indicate no pattern of tumoricidal effects by diverse plants with similar families/genus under the classes Pinopsida, Equisetopsida, Lycopodiosida, Filicosida, Liliopsida Monocotyledons or Magnoliopsida Dicotyledons. The results indicate that many of the most commonly used CAMs exhibited relatively weak tumoricidal effects including cats claw, astragalus, ginseng, echinacea, mistletoe, milk thistle, slippery elm, cayenne, chamomile, don quai, meadowsweet, motherwort and shepherd's purse. The data demonstrate that the most potent plant extracts were randomly dispersed within the plantae kingdom (LC(50) = 31-490 microg/mL) in order of the lowest LC(50) Dioscorea villosa (Dioscoreaceae) > Sanguinaria canadensis (Papaveraceae) > Dipsacus asper (Dipsacaceae) > Populus balsamifera (Salicaceae) > Boswellia carteri (Burseraceae) > Cyamopsis psoralioides (Fabaceae) > Rhamnus cathartica (Rhamnaceae) > Larrea tridentate (Zygophyllaceae) > Dichroa febrifuga (Hydrangeaceae) > Batschia canescens (Boraginaceae) > Kochia scoparia (Chenopodiaceae) > Solanum xanthocarpum (Solanaceae) > Opoponax chironium (Umbelliferae) > Caulophyllum thalictroides (Berberidaceae) > Dryopteris crassirhizoma (Dryopteridaceae) > Garcinia cambogia (Clusiaceae) > Vitex agnus-castus (Verbenaceae) > Calamus draco (Arecaceae). These findings show tumoricidal effect by extracts of wild yam root, bloodroot, teasel root, bakuchi seed, dichroa root, kanta kari, garcinia fruit, mace, dragons blood and the biblically referenced herbs: balm of gilead bud, frankincense and myrrh gum.

Inhibitory effects of cigarette smoke on glial inducible nitric oxide synthase and lack of protective properties against oxidative neurotoxins in vitro

Epidemiological studies consistently report an inverse correlation between cigarette smoking and associated risk for Parkinson's disease (PD). The degeneration of dopaminergic neurons may involve the toxic metabolic products of glial cell monoamine oxidase (MAO) and inducible nitric oxide synthase (iNOS). This study evaluates the direct protective effects of cigarette smoke (CS) against potential neurotoxic products of MAO, such as 1-methyl-4-phenylpyridinium (MPP+), 6-hydroxydopamine (6-OHDA) and hydrogen peroxide (H2O2) in brain neuroblastoma. Moreover, the effects of CS were also evaluated on endotoxin/cytokine activated glioma iNOS protein expression and MAO enzyme activity. Cigarette smoke condensates (CSCs) were acquired from Marlboro 20 Class A and Kentucky 2R4F reference research (2R4F) cigarettes. The CSCs did not protect against 6-OHDA or H2O2 toxicity in neuroblastoma, and exhibited a very mild protective effect [approximately 10%] against MPP+. Neither CSC demonstrated antioxidant capability, but conversely contained high concentration of NO2-. Paradoxically, in glioma cells, iNOS protein expression and endogenous enzymatic NO2- production were significantly blocked by both CSCs. Both CSCs also inhibited glioma MAO-A and MAO-B [1.4.3.4]. Kinetic analysis indicated that 2R4F-CSC displayed competitive inhibition and the Marlboro-CSC exerted potent competitive and non-competitive inhibition. In conclusion, these data suggest that cigarette smoke does not appear to directly protect against the toxicity of the selected neurotoxins. In contrast, CS exerts pronounced effects on glia, whereby its presence can simultaneously attenuate cytokine induction of iNOS and MAO.

Glioma cell antioxidant capacity relative to reactive oxygen species produced by dopamine

The pathology of Parkinson's disease involves oxidative damage to dopaminergic neurons of the substantia nigra. Oxidation of the dopamine (DA) neurotransmitter itself may contribute to the generation of a reactive oxygen species (ROS) and subsequent neurodegeneration. Glia cells can either exacerbate injury or exert protective properties on local neurons in the brain. We investigate glial antioxidant enzyme systems relative to ROS generated during cytokine activation, monoamine oxidase (MAO) activity and autoxidation of DA in glioma cells. Rat C6 glioma cells stimulated with lipopolysaccharide Escherichia coli 0111:B4 and interferon gamma (LPS/IFN-g) produced high levels of nitric oxide (241 nmol mg(-1) protein 24 h(-1)) but not superoxide (O(-) (2)) or hydrogen peroxide (H(2)O(2)). Basal C6 cells exhibited a rapid and robust capacity to remove exogenous H(2)O(2) within minutes. Preincubation with sodium azide but not buthionine-[S, R]-sulfoximine attenuated this response, indicating catalase as the primary enzyme responsible for this effect. The glioma catalase reaction rate was slightly attenuated by exposure to LPS/IFN-g for 24 h. However, the reduction in catalase activity was not due to nitric oxide, because both the supernatant and sodium nitroprusside had no effect on isolated catalase enzyme activity. Hydrogen peroxide was produced only through substrate-driven MAO activity in prepared lysate. However, the quantity of H(2)O(2) produced per unit time (0.46 nmol mg(-1) protein min(-1)) was negligible compared with the enormous capacity for its removal by catalase (213.9 nmol mg(-1) protein min(-1)) (> or =462 x greater). Similarly, H(2)O(2) generated by DA autoxidation per unit time (0.28 nmol mg(-1) protein equiv. min(-1)), was rapidly dissolved by glioma cells at high capacity (> or =750 x greater). In conclusion, C6 cells produce nitric oxide under cytokine/endotoxin-stimulated conditions. Moreover, C6 cells exhibit a dynamic H(2)O(2) scavenging capacity, with ample facility to dispose of the peroxide generated by both MAO activity and spontaneous DA autoxidation.

The role of oxidative stress, impaired glycolysis and mitochondrial respiratory redox failure in the cytotoxic effects of 6-hydroxydopamine in vitro

The neurotoxin, 6-hydroxydopamine (6-OHDA) has been implicated in the neurodegenerative process of Parkinson's disease. The current study was designed to elucidate the toxicological effects of 6-OHDA on energy metabolism in neuroblastoma (N-2A) cells. The toxicity of 6-OHDA corresponds to the total collapse of anaerobic/aerobic cell function, unlike other mitochondrial toxins such as MPP+ that target specific loss of aerobic metabolism. The toxicity of 6-OHDA paralleled the loss of mitochondrial oxygen (O2) consumption (MOC), glycolytic activity, ATP, H+ ion gradients, membrane potential and accumulation of the autoxidative product, hydrogen peroxide (H2O2). Removing H2O2 with nonenzymatic stoichiometric scavengers, such as carboxylic acids, glutathione and catalase yielded partial protection. The rapid removal of H2O2 with pyruvate or catalase restored only anaerobic glycolysis, but did not reverse the loss of MOC, indicating mitochondrial impairment is independent of H2O2. The H2O2 generated by 6-OHDA contributed toward the loss of anaerobic glycolysis through lipid peroxidation and lactic acid dehydrogenase inhibition. The ability of 6-OHDA to maintain oxidized cytochrome c (CYT-C-OX) in its reduced form (CYT-C-RED), appears to play a role in mitohondrial impairment. The reduction of CYT-C by 6-OHDA, was extensive, occurred within minutes, preceded formation of H2O2 and was unaffected by catalase or superoxide dismutase. At similar concentrations, 6-OHDA readily altered the valence state of iron [Fe(III)] to Fe(II), which would also theoretically sustain CYT-C in its reduced form. In isolated mitochondria, 6-OHDA had negligible effects on complex I, inhibited complex II and interfered with complex III by maintaining the substrate, CYT-C in a reduced state. 6-OHDA caused a transient and potent surge in isolated cytochrome oxidase (complex IV) activity, with rapid recovery as a result of 6-OHDA recycling CYT-C-OX to CYT-C-RED. Typical mitochondrial toxins such as MPP+, azide and antimycin appeared to inhibit the catalytic activity of ETC enzymes. In contrast, 6-OHDA alters the redox of the cytochromes, resulting in loss of substrate availability and obstruction of oxidation-reduction events. Complete cytoprotection against 6-OHDA toxicity and restored MOC was achieved by combining catalase with CYT-C (horse heart). In summary, CYT-C reducing properties are unique to catecholamine neurotransmitters, and may play a significant role in selective vulnerability of dopaminergic neurons to mitochondrial insults.

Effects of enhancing mitochondrial oxidative phosphorylation with reducing equivalents and ubiquinone on 1-methyl-4-phenylpyridinium toxicity and complex I–IV damage in neuroblastoma cells

The effects of increasing mitochondrial oxidative phosphorylation (OXPHOS), by enhancing electron transport chain components, were evaluated on 1-methyl-4-phenylpyridinium (MPP+) toxicity in brain neuroblastoma cells. Although glucose is a direct energy source, ultimately nicotinamide and flavin reducing equivalents fuel ATP produced through OXPHOS. The findings indicate that cell respiration/mitochondrial O(2) consumption (MOC) (in cells not treated with MPP+) is not controlled by the supply of glucose, coenzyme Q(10) (Co-Q(10)), NADH+, NAD or nicotinic acid. In contrast, MOC in whole cells is highly regulated by the supply of flavins: riboflavin, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), where cell respiration reached up to 410% of controls. In isolated mitochondria, FAD and FMN drastically increased complex I rate of reaction (1300%) and (450%), respectively, having no effects on complex II or III. MPP+ reduced MOC in whole cells in a dose-dependent manner. In isolated mitochondria, MPP+ exerted mild inhibition at complex I, negligible effects on complexes II-III, and extensive inhibition of complex IV. Kinetic analysis of complex I revealed that MPP+ was competitive with NADH, and partially reversible by FAD and FMN. Co-Q(10) potentiated complex II ( approximately 200%), but not complex I or III. Despite positive influence of flavins and Co-Q(10) on complexes I-II function, neither protected against MPP+ toxicity, indicating inhibition of complex IV as the predominant target. The nicotinamides and glucose prevented MPP+ toxicity by fueling anaerobic glycolysis, evident by accumulation of lactate in the absence of MOC. The data also define a clear anomaly of neuroblastoma, indicating a preference for anaerobic conditions, and an adverse response to aerobic. An increase in CO(2), CO(2)/O(2) ratio, mitochondrial inhibition or O(2) deprivation was not directly toxic, but activated metabolism through glycolysis prompting depletion of glucose and starvation. In conclusion, the results of this study indicate that the mechanism of action for MPP+, involves the inhibition of complex I and and more specifically complex IV, leading to impaired OXPHOS and MOC. Moreover, flavin dervatives control the rate of complex I/cellular respiration and Co-Q10 augments complex II [corrected].

Cytoprotection of pyruvic acid and reduced beta-nicotinamide adenine dinucleotide against hydrogen peroxide toxicity in neuroblastoma cells

Elevated production of hydrogen peroxide (H2O2) in the central nervous system has been implicated in the pathogenesis of several neurodegenerative diseases, including Parkinson's disease, ischemic reperfusion, stroke, and Alzheimer's disease. Pyruvic acid has a critical role in energy metabolism and a capability to nonenzymatically decarboxylate H2O2 into H2O. This study examined the effects of glycolytic regulation of pyruvic acid on H2O2 toxicity in murine neuroblastoma cells. Glycolytic energy substrates including D-(+)-glucose, D-(-) fructose and the adenosine transport blocker dipyridamole, were not effective in providing protection against H2O2 toxicity, negating energy as a factor. On the other hand, pyruvic acid completely prevented H2O2 toxicity, restoring the loss of ATP and cell viability. H2O2 toxicity was also attenuated by D-fructose 1,6 diphosphate (FBP), phospho (enol) pyruvate (PEP), niacinamide, beta-nicotinamide adenine dinucleotide (beta-NAD+), and reduced form (beta-NADH). Both FBP and PEP exerted positive kinetic effects on pyruvate kinase (PK) activity. Interestingly, only pyruvic acid and beta-NADH exhibited powerful stoichiometric H2O2 antioxidant properties. Further, beta-NADH may exert positive effects on PK activity. Subsequent pyruvic acid accumulation can lead to the recycling of beta-NAD+ through lactate dehydrogenase and beta-NADH through glyceraldehyde-3-phosphate dehydrogenase. It was concluded from these studies that intracellular pyruvic acid and beta-NADH appear to act in concert through glycolysis, to enhance H2O2 intracellular antioxidant capacity in neuroblastoma cells. Future research will be required to examine whether similar effects are observed in primary neuronal culture or intact tissue.

The anti-inflammatory effects of quinolinic acid in the rat

Quinolinic acid (QUIN) levels are elevated in patients and animals suffering from chronic infectious diseases. In the present study, male Sprague-Dawley rats were used to test the anti-inflammatory effects of QUIN using the carrageenan (CGN)-induced paw edema assay and the CGN sponge assay. Results of these studies indicate that QUIN (30, 100 or 300 mg/kg i.p.) caused a reduction of carrageenan-induced inflammation by as much as 80% at the highest dose. Moreover, QUIN reduced exudate volume and inhibited leukocyte migration in the sponge granuloma assay. In another experiment, the anti-inflammatory activity of QUIN was eliminated in adrenalectomized rats. QUIN did not reduce edema caused by arachidonic acid, bradykinin or compound 48/80. Neither morphine nor naloxone altered the anti-inflammatory activity of QUIN. These results may suggest that QUIN exerts its anti-inflammatory activity through a direct action on neutrophils or vascular permeability.

Food constituents attenuate monoamine oxidase activity and peroxide levels in C6 astrocyte cells

Glial cell monoamine oxidase (MAO) activity has been implicated as a contributor to oxidative neuronal damage associated with various neurodegenerative diseases. The attenuation of MAO activity may provide protection against oxidative neurodegeneration. In this investigation, the presence of MAO-B in rat C6 astrocyte cells was substantiated by dose-dependent inhibition of enzyme activity in the presence of chlorgyline-HCl and L-deprenyl. The present study evaluated various dietary-derived food constituents for evidence of inhibition on oxidative deamination of monoamines or peroxide radical trapping capacity. Results of this investigation indicate that compounds which inhibit C6 glial cell MAO enzyme activity or scavenge peroxide product include chlorogenic acid, (+)-catechin, taxifolin, (-)-epigallocatechin gallate (EGCG), fisetin, coenzyme Q0, curcumin, sesamol, morin, sesame oil, silymarin, green tea, ferulic acid, caffeic acid, and rutin hydrate. The results of this study indicate that dietary compounds can attenuate peroxide production in glial cells by either inhibiting the deamination of monoamines or acting as a free radical scavenger.

In vitro attenuation of nitric oxide production in C6 astrocyte cell culture by various dietary compounds

Excessive nitric oxide (NO) production in the brain has been correlated with neurotoxicity and the pathogenesis of several neurodegenerative diseases. NO production from neuroglial cells surrounding neurons contributes significantly to the pathogenesis of these diseases. The suppression of NO production in these cells may be beneficial in retarding many of these disorders. The present study was designed to evaluate the capacity of dietary-derived polyphenolic compounds, flavonoids, crude extracts, oils, and other food constituents in suppressing the release of NO from lipopolysaccharide (LPS)/gamma-interferon (IFN-gamma) stimulated C6 astrocyte cells. In this experiment, 61 compounds were tested, and 36 showed significant suppressive effects of NO production. The results indicate that the following compounds exhibited a dose-dependent suppressive effect of NO production with an IC50 less than 10(-3) M: quercetin, (-)-epigallocatechin gallate, morin, curcumin, apigenin, sesamol, chlorogenic acid, fisetin, (+)-taxifolin, (+)-catechin, ellagic acid, and caffeic acid. Compounds, which reduce NO production at less than 300 ppm, include milk thistle, silymarin, grapenol, and green tea. These results demonstrate a possible value for dietary compounds to inhibit the excessive production of NO.

Repeated administration of cocaine alters dopamine uptake and release in the striatum nucleus accumbens

Male Sprague-Dawley rats were administered 25 mg/kg, intraperitoneally (i.p.) cocaine-HCI twice daily for 14 consecutive days (total of 50 mg/kg), while control animals received an equivalent volume of 0.9% saline. After three days of withdrawal, the animals were sacrificed for dissection of striatal (STR) and nucleus accumbens (NA) brain regions. The treated group demonstrated a dose-dependent reduction for in vitro cocaine inhibition of [3H]dopamine (DA) uptake in the NA tissue verses controls. There were no significant differences amongst the treated and control groups for in vitro cocaine inhibition of [3H]DA in the STR. In vitro d-amphetamine (1, 5 and 10 microM)-stimulated DA release from STR tissue was not significantly different between the treated and the control groups. However, there was a significant decline in basal STR DA release and a significant enhancement of d-amphetamine (1 and 5 microM)-stimulated DA release in the NA for the treatment group versus controls. The results from the present study indicates sensitization to cocaine is primarily related to DA uptake and release in the NA.

Gestational cocaine exposure alters postnatal pituitary-adrenal axis activity and stress endurance in rats

Female pregnant Sprague-Dawley rats were injected once daily with 40 mg/kg cocaine hydrochloride or 0.9% saline from gestational day 12 (GD 12) to GD 21. From postnatal day 21 (PND 21) to PND 60, both male and female offspring were examined for stress response. Treated male and female offspring demonstrated a diminished tolerance to stress as determined by a cold water stress test performed at PND 21, 30 and 40. Base hormonal levels of adrenocorticotropin hormone (ACTH) and corticosterone were not affected by prenatal cocaine exposure in male offspring at PND 30. However, immobilization for 1 hr caused a significant sustained elevation of corticosterone levels at both PND 30 and PND 60 in male treated offspring as compared to the control group. Plasma ACTH levels were also significantly sustained after 1 hr of immobilization at PND 60 for the cocaine-treated male offspring. These results indicate both a diminished capacity to respond to stress and an abnormal heightened reactivity of the pituitary-adrenal axis in offspring exposed to cocaine in utero.

The effect of selenium on the central dopaminergic system: a microdialysis study

The effects of Selenium (Se) on central dopaminergic function were examined in male Sprague-Dawley rats. In this experiment, animals were implanted with microdialysis probes and dialysates were analyzed for dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). After reaching baseline values, sodium selenite was either injected intraperitoneally (i.p.) or directly infused into the striatum (ST) or nucleus accumbens (NA). Se administration of 3.0 mg/kg (i.p.) significantly increased (70%) DA overflow in the ST. Meanwhile direct Se perfusion (10 mM) also caused a significant elevation of synaptic DA concentrations in the ST and NA. Levels of DOPAC and HVA were minimally affected in all studies. In order to test for the effects of DA receptor activation, animals were pretreated with quinpirole (0.5 mg/kg, s.c.), an hour prior to Se (10 mM) infusion through the probe. It was found that quinpirole pre-treatment reduced Se-induced changes in DA concentrations. It was concluded from the present study that Se's central action might be related to its ability to potentiate DA function.