The role of mitochondrial/metabolic axis in development of tamoxifen resistance in breast cancer.

Only a few investigations, to our knowledge, have examined the bioenergetics of Tamoxifen (TMX) resistant individuals and reported altered mitochondrial activity and metabolic profile. The primary cause of TMX resistance is firmly suggested to be metabolic changes. Metabolic variations and hypoxia have also been linked in a bidirectional manner. Increased hypoxic levels correlate with early recurrence and proliferation and have a negative therapeutic impact on breast cancer (BC) patients. Hypoxia, carcinogenesis, and patient death are all correlated, resulting in more aggressive traits, a higher chance of metastasis, and TMX resistance. Consequently, we sought to investigate the possible role of the metabolic/hypoxial axis Long non-coding RNA (LncRNA) Taurine up-regulated 1 (TUG-1), Micro-RNA 186-5p (miR-186), Sirtuin-3 (SIRT3), Peroxisome Proliferator Activator Receptor alpha (PPAR-α), and Hypoxia-Inducible Factor-1 (HIF-1) in the development of TMX resistance in BC patients and to correlate this axis with tumor progression. Interestingly, this will be the first time to explore epigenetic regulation of this axis in BC.

Metabolic/hypoxial axis predicts tamoxifen resistance in breast cancer.

We sought in our cross-sectional study to investigate the role of metabolic/hypoxial axis in the development of tamoxifen (TMX) resistance in BC patients. Quantification of plasma LncRNA Taurine upregulated-1 (TUG-1), miRNA 186-5p (miR-186), serum Sirtuin-3 (SIRT3), Peroxisome Proliferator Activator Receptor alpha (PPAR-1 α) and Hypoxia Inducible Factor-1 (HIF-1α) was done in a cohort of patients divided into TMX-sensitive and TMX-resistant candidates. Multiple logistic regression and Receiver Operating Characteristic curve were developed for significant predictors. Plasma TUG-1 and miR-186 were significantly elevated in TMX resistant patients. Serum proteins SIRT3, PPAR-1 α and HIF-1α were deficient in TMX resistant patients compared to TMX sensitive patients, respectively. miR-186 was associated with respiratory symptoms, while, HIF-1α was associated with metastases in TMX resistant patients. Strong correlations were found between all parameters. A predictive model was constructed with TUG-1 and HIF-1α to estimate TMX resistance in BC patients with 88.3% sensitivity and 91.6% specificity. Hypoxia and metabolic dysregulations play important role in the development of TMX resistance in BC patients. Correlation between hypoxia, carcinogenesis and patient's mortality have led to more aggressive phenotypes, increased risk of metastasis and resistance to TMX.

Association between interleukin 28B polymorphism and sustained virological response to sofosbuvir plus daclatasvir in chronic hepatitis C genotype 4 Egyptian patients.

WHAT IS KNOWN AND OBJECTIVE: Sofosbuvir has been approved as the first nonstructural protein 5B polymerase inhibitor with pan-genotypic activity against the hepatitis C (HCV) virus. Daclatasvir is a first-in-class hepatitis C virus nonstructural protein 5A replication complex inhibitor. We aimed to evaluate the usefulness of the reference single nucleotide polymorphism (rs12979860) interleukin 28B (CC genotype) for predicting sustained virological response to sofosbuvir plus daclatasvir in Egyptian patients infected with HCV-4. METHODS: Samples were collected at week zero. One hundred and thirty-one patients who reached the end of treatment (at week 12) were divided into three groups, according to their interleukin 28B genotype: Group A included 31 patients (CC genotype), group B included 79 patients (CT genotype) and group C had 21 patients (TT genotype). All patients received treatment for 3 months in the form of sofosbuvir plus daclatasvir with ribavirin (in case of cirrhotic patients) or without ribavirin (in case of non-cirrhotic patients). RESULTS AND DISCUSSION: Sustained virological response rate was significantly higher in patients with IL28B (CC genotype) vs. (non-CC genotype) (100 vs.88%) (p < 0.0001).These patients also showed lower rates of post-treatment relapse and non-response, compared with the CT and TT patients (0% vs. (7.59% and 28.5%, respectively) (p < 0.0001). Also, patients with CC genotype showed higher sustained virological response than non-CC genotypes on both cirrhotic (100% vs. 68.75%) and non-cirrhotic patients (100% vs. 91.66%) (p ≤ 0.0001). WHAT IS NEW AND CONCLUSION: Our results suggest that IL28B genotype contributes to the prediction of response to sofosbuvir plus daclatasvir.

Cyclosporin A activates human hepatocellular carcinoma (HepG2 cells) proliferation: implication of EGFR-mediated ERK1/2 signaling pathway.

One of the most common causes of cancer mortality worldwide is hepatocellular carcinoma (HCC). Extracellular signal-regulated kinase (ERK1/2) pathway has been shown to play an important role in the development and progression of HCC. Here, we demonstrate that the immunosuppressive agent cyclosporin A (CsA) has the ability to increase the cellular growth in HCC (HepG2 cells) via activation of ERK1/2 signaling cascade. It was found that ERK1/2 phosphorylation induced by CsA was highly reduced in the presence of the reactive oxygen species (ROS) scavenger polyethylene glycol-superoxide dismutase (PEG-SOD). Furthermore, it was observed that inhibition of metalloproteinase activity using TAPI-2 prevents ERK1/2 activation by CsA. Moreover, a disintegrin and metalloproteinase domain 17 (ADAM-17) activity was found to be critical for ERK phosphorylation by CsA. In addition, CsA-induced ERK phosphorylation was highly reduced in the presence of either neutralizing anti-heparin-binding-epidermal growth factor (HB-EGF) antibody or UO126 (MEK inhibitor). By using the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478, it was found that EGFR is critical for ERK phosphorylation induced by CsA. Furthermore, CsA-induced cell proliferation was strongly reduced in the presence of either PEG-SOD or TAPI-2 or neutralizing anti-ADAM17 antibody or neutralizing anti-HB-EGF antibody or AG1478 or UO126. Collectively, these data demonstrate that CsA has the ability to activate ERK1/2 signaling cascade that could be translated into an increase in HepG2 cell proliferation. Furthermore, these data support the role of ROS, ADAM-17, and EGFR in ERK1/2 signaling activation and subsequent cell proliferation induced by CsA in HepG2 cells.

Functional characterization of α7 nicotinic acetylcholine and NMDA receptor signaling in SH-SY5Y neuroblastoma cells in an ERK phosphorylation assay.

In the present study, the functional properties of α7 nicotinic acetylcholine receptors (α7 nAChRs) and N-methyl-D-aspartate receptors (NMDARs) endogenously expressed in SH-SY5Y human neuroblastoma cells were characterized in an extracellular-signal regulated kinase (ERK) phosphorylation assay. Both choline and N-methyl-D-aspartate (NMDA) mediated robust concentration-dependent increases in ERK phosphorylation in the SH-SY5Y cells, exhibiting EC50 values in good agreement with those reported for the agonists at recombinant α7 nAChRs and NMDARs, respectively. Importantly, the responses evoked by choline (10 mM) and by NMDA (50 µM) were significantly inhibited by the α7-selective antagonist α-bungarotoxin (100 nM) and by the NMDAR-selective antagonist MK-801 (50 µM), respectively. The increased ERK phosphorylation levels observed upon co-application of choline (1, 3, 10 mM) and NMDA (50 µM) compared to those produced by the two agonists on their own were fully reconcilable with additive effects and did not reveal substantial synergy between α7 nAChR and NMDAR signaling. Interestingly, however, the responses evoked by the "choline (10 mM) - NMDA (50 µM)" combination were almost completely inhibited by α-bungarotoxin (100 nM) as well as by MK-801 (50 µM), suggesting some sort of a link between α7 nAChR- and NMDAR-mediated ERK phosphorylation. Finally, oligomeric amyloid-ß1-42 peptide (1000 nM) mediated robust inhibition of the ERK phosphorylation induced by choline (10 mM), NMDA (50 µM) and the "choline (10 mM) - NMDA (50 µM)" combination. In conclusion, ERK phosphorylation measurements in SH-SY5Y cells provides a robust assay for studies of α7 nAChR- and NMDAR-mediating signaling and putative functional interactions between the receptors.

Probing the putative α7 nAChR/NMDAR complex in human and murine cortex and hippocampus: Different degrees of complex formation in healthy and Alzheimer brain tissue.

α7 nicotinic acetylcholine receptors (nAChRs) and N-methyl-D-aspartate receptors (NMDARs) are key mediators of central cholinergic and glutamatergic neurotransmission, respectively. In addition to numerous well-established functional interactions between α7 nAChRs and NMDARs, the two receptors have been proposed to form a multimeric complex, and in the present study we have investigated this putative α7 nAChR/NMDAR assembly in human and murine brain tissues. By α-bungarotoxin (BGT) affinity purification, α7 and NMDAR subunits were co-purified from human and murine cortical and hippocampal homogenates, substantiating the notion that the receptors are parts of a multimeric complex in the human and rodent brain. Interestingly, the ratios between GluN1 and α7 levels in BGT pull-downs from cortical homogenates from Alzheimer's disease (AD) brains were significantly lower than those in pull-downs from non-AD controls, indicating a reduced degree of α7 nAChR/NMDAR complex formation in the diseased tissue. A similar difference in GluN1/α7 ratios was observed between pull-downs from cortical homogenates from adult 3xTg-AD and age-matched wild type (WT) mice, whereas the GluN1/α7 ratios determined in pull-downs from young 3xTg-AD and age-matched WT mice did not differ significantly. The observation that pretreatment with oligomeric amyloid-ß1-42 reduced GluN1/α7 ratios in BGT pull-downs from human cortical homogenate in a concentration-dependent manner provided a plausible molecular mechanism for this observed reduction. In conclusion, while it will be important to further challenge the existence of the putative α7 nAChR/NMDAR complex in future studies applying other methodologies than biochemical assays and to investigate the functional implications of this complex for cholinergic and glutamatergic neurotransmission, this work supports the formation of the complex and presents new insights into its regulation in healthy and diseased brain tissue.

Exosomal miR-940 maintains SRC-mediated oncogenic activity in cancer cells: a possible role for exosomal disposal of tumor suppressor miRNAs.

Exosomes have emerged as important mediators of diverse biological functions including tumor suppression, tumor progression, invasion, immune escape and cell-to-cell communication, through the release of molecules such as mRNAs, miRNAs, and proteins. Here, we identified differentially expressed exosomal miRNAs between normal epithelial ovarian cell line and both resistant and sensitive ovarian cancer (OC) cell lines. We found miR-940 as abundant in exosomes from SKOV3-IP1, HeyA8, and HeyA8-MDR cells. The high expression of miR-940 is associated with better survival in patients with ovarian serous cystadenocarcinoma. Ectopic expression of miR-940 inhibited proliferation, colony formation, invasion, and migration and triggered G0/G1 cell cycle arrest and apoptosis in OC cells. Overexpression of miR-940 also inhibited tumor cell growth in vivo. We showed that proto-oncogene tyrosine-protein kinase (SRC) is directly targeted by miR-940 and that miR-940 inhibited SRC expression at mRNA and protein levels. Following this inhibition, the expression of proteins downstream of SRC, such as FAK, paxillin and Akt was also reduced. Collectively, our results suggest that OC cells secrete the tumor-suppressive miR-940 into the extracellular environment via exosomes, to maintain their invasiveness and tumorigenic phenotype.

Coadministration of ezetimibe with pegylated interferon plus ribavirin could improve early virological response in chronic hepatitis C obese Egyptian patients.

BACKGROUND: Ezetimibe has been reported to inhibit viral entry and to reduce BMI and has been proposed as a novel therapeutic agent for chronic hepatitis C (CHC), potentiating the effects of pegylated interferon and ribavirin (peg-IFN/RBV). OBJECTIVE: The aim of the study was to assess the effects of ezetimibe coadministration with peg-IFN/RBV combination on the early virological response (EVR) rates in nonobese and obese patients with CHC genotype 4 (CHC-4). PATIENTS AND METHODS: A total of 144 CHC-4 patients were divided into two groups; group 1 included nonobese patients (n=76) and group 2 included obese patients (n=68). Each group was further subclassified into equal control and treated groups. The control groups received peg-IFN/RBV combination for 24 weeks, and the treated groups received peg-IFN/RBV plus ezetimibe for 12 weeks and then only peg-IFN/RBV for the remaining 12 weeks. RESULTS: The study revealed that EVR significantly improved in the obese patients (85.3 vs. 64.7% in the treated and control groups, respectively, at P<0.05) without any significant improvement in the nonobese patients. Biochemical responses (defined as normalization of alanine aminotransferase at week 12) were markedly improved in the treated groups in both the nonobese and obese groups compared with their respective controls. CONCLUSION: The addition of ezetimibe to peg-IFN/RBV combination significantly improves EVR rates in obese patients compared with nonobese patients, and remarkably improves the biochemical responses in both obese and nonobese patients with CHC-4. This may shed light on a new strategy for the treatment of CHC, particularly in obese Egyptian patients.

Thymoquinone supplementation ameliorates acute endotoxemia-induced liver dysfunction in rats.

Endotoxemia caused by lipopolysaccharide (LPS) produced an inflammatory condition contributing to multiple organ failure. This study was carried out to investigate the effects of thymoquinone (TQ), the main constituent of Nigella sativa seeds, against LPS-induced hepatotoxicity. The obtained data revealed that LPS markedly depleted liver reduced glutathione (GSH) and significantly increased the level of malondialdehyde (MDA) and the activity of caspase-3 enzyme in the liver. Serum tumour necrosis factor-alpha (TNF-alpha) and bilirubin levels and the activities of alkaline phosphatase (ALP) and gamma-glutamyl transferase (gamma-GT) enzymes were markedly increased in LPS-treated rats. TQ supplementation resulted in normalization of liver GSH and decreases in the levels of MDA and caspase-3 activity in the liver with reduction of serum TNF-alpha, serum total bilirubin and the activities of ALP and gamma-GTenzymes. Histopathological examination revealed that TQ administration improved LPS-induced pathological abnormalities in liver tissues. The present study conclude that TQ reduced acute endoxemia-induced liver dysfunction at least in part by its anti-inflammatory, antiapoptotic and antioxidant activities.

Protective effect of N-acetylcysteine against carmustine-induced myelotoxicity in rats.

Carmustine (BCNU) is used to treat a variety of tumors, in particular gliomas. However, the success of such treatment is limited by severe myelosuppression. The role of N-acetylcysteine (NAC) in protection against BCNU-induced myelotoxicity is still needed to be explored. The aim of this work is to study the possible protective role of NAC against BCNU-induced myelotoxicity through evaluation of apoptosis, lipid peroxidation, antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase(CAT)) as well as glutathione (GSH) content in bone marrow cells of rats. Administration of BCNU in a single dose (30 mg/kg, i.p.) significantly decreased RBCs, WBCs and platelets counts as well as hemoglobin level. In addition, BCNU produced a significant apoptotic effect as well as a significant lipid peroxidation in bone marrow cells. Pretreatment of animals with NAC (150 mg/kg, i.p.) daily for 5 days significantly ameliorated the changes in oxidant and antioxidant parameters as well as apoptosis induced by BCNU. In addition the pattern of blood parameters was shifted markedly to normal values in animals pretreated with NAC when compared to BCNU-treated group. Conclusively, NAC could have a potential protective effect against BCNU-induced myelotoxicity; an effect that is mainly attributed to the antioxidant property.

Metallothionein induction reduces caspase-3 activity and TNFalpha levels with preservation of cognitive function and intact hippocampal neurons in carmustine-treated rats.

Hippocampal integrity is essential for cognitive functions. On the other hand, induction of metallothionein (MT) by ZnSO(4) and its role in neuroprotection has been documented. The present study aimed to explore the effect of MT induction on carmustine (BCNU)-induced hippocampal cognitive dysfunction in rats. A total of 60 male Wistar albino rats were randomly divided into four groups (15/group): The control group injected with single doses of normal saline (i.c.v) followed 24 h later by BCNU solvent (i.v). The second group administered ZnSO(4) (0.1 micromol/10 microl normal saline, i.c.v, once) then BCNU solvent (i.v) after 24 h. Third group received BCNU (20 mg/kg, i.v, once) 24 h after injection with normal saline (i.c.v). Fourth group received a single dose of ZnSO(4) (0.1 micromol/10 microl normal saline, i.c.v) then BCNU (20 mg/kg, i.v, once) after 24 h. The obtained data revealed that BCNU administration resulted in deterioration of learning and short-term memory (STM), as measured by using radial arm water maze, accompanied with decreased hippocampal glutathione reductase (GR) activity and reduced glutathione (GSH) content. Also, BCNU administration increased serum tumor necrosis factor-alpha (TNFalpha), hippocampal MT and malondialdehyde (MDA) contents as well as caspase-3 activity in addition to histological alterations. ZnSO(4) pretreatment counteracted BCNU-induced inhibition of GR and depletion of GSH and resulted in significant reduction in the levels of MDA and TNFalpha as well as the activity of caspase-3. The histological features were improved in hippocampus of rats treated with ZnSO(4) + BCNU compared to only BCNU-treated animals. In conclusion, MT induction halts BCNU-induced hippocampal toxicity as it prevented GR inhibition and GSH depletion and counteracted the increased levels of TNFalpha, MDA and caspase-3 activity with subsequent preservation of cognition.

Pro-inflammatory and oxidative stress pathways which compromise sperm motility and survival may be altered by L-carnitine.

The testis is an immunologically privileged organ. Sertoli cells can form a blood-testis barrier and protect sperm cells from self-immune system attacks. Spermatogenesis may be inhibited by severe illness, bacterial infections and chronic inflammatory diseases but the mechanism(s) is poorly understood. Our objective is to help in understanding such mechanism(s) to develop protective agents against temporary or permanent testicular dysfunction. Lipopolysaccaride (LPS) is used as a model of animal sepsis while L-carnitine (LCR) is used as a protective agent. A total of 60 male Swiss albino rats were divided into four groups (15/group). The control group received Saline; the 2(nd) group was given LCR (500 mg/kg i.p, once). The third group was treated with LPS (5 mg/kg i.p once) and the fourth group received LCR then LPS after three hours. From each group, five rats were used for histopathological examination. Biochemical parameters were assessed in the remaining ten rats. At the end of the experiment, animals were lightly anaesthetized with ether where blood samples were collected and testes were dissected on ice. Sperm count and motility were evaluated from cauda epididymis in each animal. Also, oxidative stress was evaluated by measuring testicular contents of reduced glutathione (GSH), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-HDG, the DNA adduct for oxidative damage) in testicular DNA. The pro-inflammatory mediator nitric oxide (NO) in addition to lactate dehydrogenase (LDHx) isoenzyme-x activity as an indicator for normal spermatozoal metabolism were assessed in testicular homogenate. Serum interlukin (IL)-2 level was also assessed as a marker for T-helper cell function. The obtained data revealed that LPS induced marked reductions in sperm's count and motility, obstruction in seminiferous tubules, hypospermia and dilated congested blood vessels in testicular sections concomitant with decreased testicular GSH content and LDHx activity. Moreover, the testicular levels of MDA, 8-HDG (in testicular DNA) and NO as well as serum IL-2 level were increased. Administration of LCR before LPS returned both sperm count and motility to normal levels. Also, contents of testicular GSH, MDA, 8-HDG and NO returned back to the corresponding control values. In addition, serum IL-2 level as well as histological abnormalities were markedly improved in LCR + LPS-treated rats. In conclusion, LPS increased proinflammatory and oxidative stress markers in the testis leading to a marked testicular dysfunction. L-carnitine administration ameliorates these effects by antioxidant and/or anti-inflammatory mechanisms suggesting a protective role against male infertility in severely infected or septic patients.

Systemic administration of Zn2+ during the reperfusion phase of transient cerebral ischaemia protects rat hippocampus against iron-catalysed postischaemic injury.

1. The aim of the present study was to test the protective role of intravenous Zn(2+) against iron-catalysed reperfusion injury in the hippocampus of ischaemic rats. 2. One hundred adult male Wistar albino rats were randomly divided into five groups. Rats in the first group were subjected to surgery (sham operation) without induction of cerebral ischaemia and injected with normal saline (i.v.). The second group of sham-operated rats were injected with 6 mg/kg, i.v., ZnCl(2). In the third group, rats were subjected to cerebral ischaemia for 60 min. Animals in the fourth group were subjected to cerebral ischaemia for 60 min followed by 8 h reperfusion. In the fifth group, rats were subjected to cerebral ischaemia for 60 min, followed by 8 h reperfusion with injection of a single dose of ZnCl(2) (6 mg/kg, i.v.) during the first 5 min of the reperfusion period. After reperfusion, animals were killed, their brains were dissected out on ice and the two hippocampi from each animal were isolated and analysed. 3. Cerebral ischaemia induced an increase in the iron content, lipidic peroxidation, apoptosis and metallothionein (MT) in the hippocampus. These effects were significantly increased in the hippocampus of ischaemic rats subjected to 8 h reperfusion compared with ischaemic non-reperfused rats. Intravenous administration of ZnCl(2)decreased the accumulation of iron, lipidic peroxidation and apoptosis produced by reperfusion, but increased the level of MT. 4. Data from the present study suggest that, after 1 h ischaemia, there is an increase in the permeability of the blood-brain barrier and this allows penetration of i.v. injected ZnCl(2), which can induce expression of brain MT, increase the anti-oxidant capacity and diminish iron-catalysed lipid peroxidation and apoptosis. This may give new insights as to how to improve the outcome for stroke patients.