Mechanisms involved in the pro- and anti-apoptotic role of NO in human leukemia

Trilobolide-6-O-isobutyrate from Sphagneticola trilobata acts by inducing oxidative stress, metabolic changes and apoptosis-like processes by caspase 3/7 activation of human lung cancer cell lines

BACKGROUND

Lung cancer, a chronic and heterogeneous disease, is the leading cause of cancer-related death on a global scale. Presently, despite a variety of available treatments, their effectiveness is limited, often resulting in considerable toxicity and adverse effects. Additionally, the development of chemoresistance in cancer cells poses a challenge. Trilobolide-6-O-isobutyrate (TBB), a natural sesquiterpene lactone extracted from Sphagneticola trilobata, has exhibited antitumor effects. Its pharmacological properties in NSCLC lung cancer, however, have not been explored.

PURPOSE

This study evaluated the impact of TBB on the A549 and NCI-H460 tumor cell lines in vitro, examining its antiproliferative properties and initial mechanisms of cell death.

METHODS

TBB, obtained at 98 % purity from S. trilobata leaves, was characterized using chromatographic techniques. Subsequently, its impact on inhibiting tumor cell proliferation in vitro, TBB-induced cytotoxicity in LLC-MK2, THP-1, AMJ2-C11 cells, as well as its effects on sheep erythrocytes, and the underlying mechanisms of cell death, were assessed.

RESULTS

In silico predictions have shown promising drug-likeness potential for TBB, indicating high oral bioavailability and intestinal absorption. Treatment of A549 and NCI-H460 human tumor cells with TBB demonstrated a direct impact, inducing significant morphological and structural alterations. TBB also reduced migratory capacity without causing toxicity at lower concentrations to LLC-MK2, THP-1 and AMJ2-C11 cell lines. This antiproliferative effect correlated with elevated oxidative stress, characterized by increased levels of ROS, superoxide anion radicals and NO, accompanied by a decrease in antioxidant markers: SOD and GSH. TBB-stress-induced led to changes in cell metabolism, fostering the accumulation of lipid droplets and autophagic vacuoles. Stress also resulted in compromised mitochondrial integrity, a crucial aspect of cellular function. Additionally, TBB prompted apoptosis-like cell death through activation of caspase 3/7 stressors.

CONCLUSION

These findings underscore the potential of TBB as a promising candidate for future studies and suggest its viability as an additional component in the development of novel anticancer drugs prototypes.

Analysis of the response to cigarette smoke exposure in cell coculture and monoculture based on bionic-lung microfluidic chips

BACKGROUND

In vitro toxicity assessment studies with various experimental models and exposure modalities frequently generate diverse outcomes. In the prevalent experimental, aerosol pollutants are dissolved in culture medium through capture for exposure to two-dimensional planar cellular models in multiwell plates via immersion. However, this approach can generate restricted and inconclusive experimental data, significantly constraining the applicability of risk assessment outcomes. Herein, the in vitro cocultivation of lung epithelial and/or vascular endothelial cells was performed using self-designed bionic-lung microfluidic chip housing a gas-concentration gradient generator (GCGG) unit. Exposure experiments involving a concentration gradient of cigarette smoke (CS) aerosol were then conducted through an original assembled real-time aerosol exposure system.

RESULTS

Transcriptomic analysis revealed a potential involvement of the cGMP-signaling pathway following online CS aerosol exposure on different cell culture models. Furthermore, distinct responses to different concentrations of CS aerosol exposure on different culture models were highlighted by detecting inflammation- and oxidative stress-related biomarkers (i.e., cell viability, reactive oxygen species, nitric oxide, IL-6, IL-8, TNF-α, GM-CSF, malondialdehyde, and superoxide dismutase).

SIGNIFICANT

The results underscore the importance of improving chip biomimicry while addressing multi-throughput demands, given the substantial influence of the coculture model on cellular responses triggered by CS. Furthermore, the coculture model exhibited a mutually beneficial protective effect on cells at low CS concentrations within the GCGG unit, yet revealed a mutually amplified damaging effect at higher CS concentrations in contrast to the monoculture model.

Discovery and bioassay of disubstituted β-elemene-NO donor conjugates: synergistic enhancement in the treatment of leukemia

Natural products are essential sources of antitumor drugs. One such molecule, β-elemene, is a potent antitumor compound extracted from Curcuma wenyujin. In the present investigation, a series of novel 13,14-disubstituted nitric oxide (NO)-donor β-elemene derivatives were designed, with β-elemene as the foundational compound, and subsequently synthesized to evaluate their therapeutic potential against leukemia. Notably, the derivative labeled as compound 13d demonstrated a potent anti-proliferative activity against the K562 cell line, with a high NO release. In vivo studies indicated that compound 13d could effectively inhibit tumor growth, exhibiting no discernible toxic manifestations. Specifically, a significant tumor growth inhibition rate of 62.9% was observed in the K562 xenograft tumor mouse model. The accumulated data propound the potential therapeutic application of compound 13d in the management of leukemia.

Tight Junction Protein Signaling and Cancer Biology

Tight junctions (TJs) are intercellular protein complexes that preserve tissue homeostasis and integrity through the control of paracellular permeability and cell polarity. Recent findings have revealed the functional role of TJ proteins outside TJs and beyond their classical cellular functions as selective gatekeepers. This is illustrated by the dysregulation in TJ protein expression levels in response to external and intracellular stimuli, notably during tumorigenesis. A large body of knowledge has uncovered the well-established functional role of TJ proteins in cancer pathogenesis. Mechanistically, TJ proteins act as bidirectional signaling hubs that connect the extracellular compartment to the intracellular compartment. By modulating key signaling pathways, TJ proteins are crucial players in the regulation of cell proliferation, migration, and differentiation, all of which being essential cancer hallmarks crucial for tumor growth and metastasis. TJ proteins also promote the acquisition of stem cell phenotypes in cancer cells. These findings highlight their contribution to carcinogenesis and therapeutic resistance. Moreover, recent preclinical and clinical studies have used TJ proteins as therapeutic targets or prognostic markers. This review summarizes the functional role of TJ proteins in cancer biology and their impact for novel strategies to prevent and treat cancer.

Protective effect of copper II-albumin complex against aflatoxin B1- induced hepatocellular toxicity: The impact of Nrf2, PPAR-γ, and NF-kB in these protective effects

Copper II-Albumin complex (Cu-II-Albumin complex) is a novel therapeutic target that has been used as anti-inflammatory, antioxidant, and anti-gastrointestinal toxicity. In this study, 40 rats were divided into four groups, normal control (NC), aflatoxicosed group (AF) that received Aflatoxin B1 (AFB1) (50 μg/kg of the AFB1 daily for 3 weeks), AFB1-Cu-II-Albumin prophylactic group (AF/CUC-P) that subjected to intermittent treatment between AFB1 and Cu-II-Albumin complex (0.05 g/kg Cu-II-Albumin complex) day after day for 3 weeks and AFB1-Cu-II-albumin treatment group (AF/CUC-T) that received AFB1 for 3 weeks and Cu-II-albumin complex for another 3 weeks. The hepatocellular protective effect of the Cu-II-albumin complex was assessed by evaluating the liver functions markers, hepatic histopathology, reactive oxygen species (ROS) levels (Nitric Oxide (NO) and malondialdehyde (MDA)), apoptotic genes (caspase-3 and tumor necrosis factor receptor 1 [TNF-R1]) expressions, and serological and molecular biomarkers of hepatocellular carcinoma (histamine and Glucose-Regulated Protein 78 [GRP78], respectively). Our finding showed that Cu-II-Albumin Complex administration had restored liver function, oxidative stress levels, enhanced liver tissue recovery, and reduced the expression of the apoptotic genes of the aflatoxicosed rats. In conclusion, the current study results demonstrated the protective effect of Cu-II-albumin complex against AFB1-induced hepatocellular toxicity. PRACTICAL APPLICATIONS: The protective effect of Cu-II-Albumin Complex against AFB1-induced hepatocellular toxicity by assessing oxidative stress, liver biomarkers, inflammation, and histological changes of liver tissues. The protective mechanism of the Cu-II-albumin complex was also investigated. More clinical studies are required to evaluate the potential of using the Cu-II-albumin complex as a therapeutic agent against hepatocellular toxicity.

Alpha-Ketoglutarate or 5-HMF: Single Compounds Effectively Eliminate Leukemia Cells via Caspase-3 Apoptosis and Antioxidative Pathways

Background: We recently showed that a combined solution containing alpha-ketoglutarate (aKG) and 5-hydroxymethyl-furfural (5-HMF) has a solid antitumoral effect on the Jurkat cell line due to the fact of its antioxidative, caspase-3 and apoptosis activities, but no negative effect on human fibroblasts was obtained. The question arises how the single compounds, aKG and 5-HMF, affect peroxynitrite (ONOO⁻) and nitration of tyrosine residues, Jurkat cell proliferation and caspase-activated apoptosis. Methods: The ONOO⁻ luminol-induced chemiluminescence reaction was used to measure the ONOO⁻ scavenging function of aKG or 5-HMF, and their protection against nitration of tyrosine residues on bovine serum albumin was estimated with the ELISA technique. The Jurkat cell line was cultivated in the absence or presence of aKG or 5-HMF solutions between 0 and 3.5 µM aKG or 0 and 4 µM 5-HMF. Jurkat cells were tested for cell proliferation, mitochondrial activity and caspase-activated apoptosis. Results: aKG showed a concentration-dependent reduction in ONOO⁻, resulting in a 90% elimination of ONOO⁻ using 200 mM aKG. In addition, 20 and 200 mM 5-HMF were able to reduce ONOO⁻ only by 20%, while lower concentrations of 5-HMF remained stable in the presence of ONOO⁻. Nitration of tyrosine residues was inhibited 4 fold more effectively with 5-HMF compared to aKG measuring the IC50%. Both substances, aKG and 5-HMF, were shown to cause a reduction in Jurkat cell growth that was dependent on the dose and incubation time. The aKG effectively reduced Jurkat cell growth down to 50% after 48 and 72 h of incubation using the highest concentration of 3.5 µM, and 1, 1.6, 2, 3 and 4 µM 5-HMF inhibited any cell growth within (i) 24 h; 1.6, 2, 3 and 4 µM 5-HMF within 48 h (ii); 2, 3 and 4 µM 5-HMF within 72 h (iii). Furthermore, 4 µM was able to eliminate the starting cell number of 20,000 cells after 48 and 72 h down to 11,233 cells. The mitochondrial activity measurements supported the data on aKG or 5-HMF regarding cell growth in Jurkat cells, in both a dose- and incubation-time-dependent manner: the highest concentration of 3.5 µM aKG reduced the mitochondrial activity over 24 h (67.7%), 48 h (57.9%) and 72 h (46.8%) of incubation with Jurkat cells compared to the control incubation without aKG (100%). 5-HMF was more effective compared to aKG; the mitochondrial activity in the presence of 4 µM 5-HMF decreased after 24 h down to 68.4%, after 48 h to 42.9% and after 72 h to 32.0%. Moreover, 1.7 and 3.4 µM aKG had no effect on caspase-3-activated apoptosis (0.58% and 0.56%) in the Jurkat cell line. However, 2 and 4 µM 5-HMF increased the caspase-3-activated apoptosis up to 22.1% and 42.5% compared to the control (2.9%). A combined solution of 1.7 µM aKG + 0.7 µM 5-HMF showed a higher caspase-3-activated apoptosis (15.7%) compared to 1.7 µM aKG or 2 µM 5-HMF alone. In addition, 3.5 µM µg/mL aKG + 1.7 µM 5-HMF induced caspase-activated apoptosis up to 55.6% compared to 4.5% or 35.6% caspase-3 activity using 3.5 µM aKG or 4 µM 5-HMF. Conclusion: Both substances showed high antioxidative potential in eliminating either peroxynitrite or nitration of tyrosine residues, which results in a better inhibition of cell growth and mitochondrial activity of 5-HMF compared to aKG. However, caspase-3-activated apoptosis measurements revealed that the combination of both substances synergistically is the most effective compared to single compounds.

The ginger extract could improve diabetic retinopathy by inhibiting the expression of e/iNOS and G6PDH, apoptosis, inflammation, and angiogenesis

Diabetic retinopathy is a complication of diabetes, caused by high blood sugar levels damaging the retina. It is the result of damage to the small blood vessels and neurons of the retina. Ginger and its phytochemical compounds can improve oxidative damage and inflammation. However, the effects of this plant on ocular expression G6PDH and e/iNOS, eye cell apoptosis, and angiogenesis are not well known in this tissue. Therefore, the aim of this study was to evaluate the therapeutic potential of ginger extract on rats with type 2 diabetic retinopathy. Thirty-two Wistar rats were randomly divided into four controlled and treated groups. The serum level of metabolic factors such as lipid profiles, insulin and glucose, and the level of oxidative biomarkers along with the TNF-α level in eye tissue were measured. The expression of NF-κB, VEGF, BAX, Bcl-2, caspase-3, e/iNOS, and G6PDH in eye tissue was measured. Serum levels of lipid profiles, glucose, and insulin, oxidative and inflammatory markers were significantly increased in the diabetic group compared to control. While, treatment with ginger extract could significantly improve these factors in diabetic rats. Moreover, the ocular expression of e/iNOS, G6PDH, VEGF, NF-κB, and genes involved in apoptosis was changed in diabetic rats. However, treatment with ginger extract could ameliorate these changes in the diabetic-treated group. It can be concluded that ginger extract could improve diabetic retinopathy by inhibiting oxidative damage, inflammation, iNOS, VEGF, apoptosis, and improving eNOS and G6PDH. PRACTICAL APPLICATIONS: Microvascular complications of diabetes such as retinopathy can be one of the main causes of disability in people with diabetes. Chronic hyperglycemia, oxidative stress, inflammation, and apoptosis cause diabetic retinopathy through retinal damage. Ginger, on the other hand, is an available, inexpensive, and uncomplicated medicinal plant that contains more than 20 different phytochemicals, such as gingerol and shogaol, which have anti-inflammatory, antioxidant, antihypertensive, hypoglycemic, and hypolipidemic properties. The results of our study showed well that the ginger extract could improve diabetic retinopathy by inhibiting the expression of e/iNOS and G6PDH and oxidative damage, apoptosis, inflammation, and angiogenesis. Therefore, ginger and its compounds can be a good option to improve the complications of diabetes.

Nitric Oxide Synthase Potentiates the Resistance of Cancer Cell Lines to Anticancer Chemotherapeutics

BACKGROUND

Despite the advancement in the fields of medical science and molecular biology, cancer is still the leading cause of death worldwide. Chemotherapy is a choice for treatment; however, the acquisition of chemo-resistance is a major impediment to cancer management. Many mechanisms have been postulated regarding the acquisition of chemo-resistance in breast cancer the impact on cellular signaling and the induction of apoptosis in tumour cells. The mechanism of the apoptotic mutation of p53 and bcl-2 proteins is commonly associated with increased resistance to apoptosis and, therein, to chemotherapy.

OBJECTIVES

The current study was aimed to investigate A172 and MDA-MB-231 cancer cells' sensitivity against chemotherapeutic drugs, including cisplatin, doxorubicin, and paclitaxel with different doses. Moreover, it estimates the resistance of cancer cells by evaluating nitric oxide synthase (NOS) expression and evaluate its correlation with the expression profile proteins of the apoptosis regulating Bcl-2 family.

METHODS

Dose-dependent sensitivity to cisplatin, doxorubicin, or paclitaxel was evaluated on spheroid cultured A172 and MDA-MB-231 cells lines as measured by time-lapse microscopy over a 72h period. Expressions of two nitric oxides (NO) synthases isoforms (iNOS, eNOS), anti-apoptotic (Bcl-2, phospho-Bcl-2, Mcl-1, and Bcl-xL), and pro-apoptotic (BID, Bim, Bok, Bad, Puma, and Bax) were evaluated by Western blot. The effect of NO modulation on anti- and pro-apoptotic molecule expression was also studied using Western blot.

RESULT

A172 cells show more resistance to chemotherapy drugs than MDA-MB-231 cancer cells. Therefore, they need higher doses for apoptosis. Resistance of gliomas might be returned to the higher significant expression of endothelial eNOS expression. It was clear that there is not a significant effect of NO modulation on the expression of pro-and anti-apoptotic proteins on both cell lines.

CONCLUSION

The present work provides a putative mechanism for the acquisition of drug resistance in breast cancer and glioma, which might be significant for clinical outcomes.

Expression of inducible NOS is indispensable for the antiproliferative and proapoptotic effect of imatinib in BCR-ABL positive cells

Chronic myeloid leukemia (CML) is characterized by constitutive BCR-ABL kinase activity, an aggressive proliferation of immature cells, and reduced differentiation. Targeting tyrosine kinase activity of BCR-ABL with imatinib is an effective therapy for the newly diagnosed CML patients; however, 20%-30% of the patients initially treated with imatinib eventually experience treatment failure. Therefore, early identification of these patients is of high clinical relevance. In the present study, we by undertaking a direct comparison of inducible NOS (iNOS) status in neutrophils from healthy volunteers, newly diagnosed, imatinib responder, and resistant CML patients as well as by conducting in vitro studies in K562 cells demonstrated that inhibition of BCR-ABL by imatinib or siRNA significantly enhanced NO generation and iNOS expression. Indeed, patients exhibiting treatment failure or imatinib resistance were less likely to induce NO generation/iNOS expression. Our findings further demonstrated that imatinib mediated antiproliferative and proapoptotic effect in BCR-ABL⁺ cells associated with enhanced iNOS expression, and it was significantly prevented in the presence of L-NAME, 1400W, or iNOS siRNA. Overexpression of iNOS in K562 cells expectedly enhanced imatinib sensitivity on cytostasis and apoptosis, even at lower concentration (0.1 μM) of imatinib. Mechanistically, imatinib or BCR-ABL siRNA following deglutathionylation of NF-κB, enhanced its binding to iNOS promoter and induced iNOS transcription. Deglutathionylation of procaspase-3 however associated with increased caspase-3 activity and cell apoptosis. Taken together, results obtained suggest that monitoring NO/iNOS level could be useful to identify patients likely to be responsive or resistant to imatinib and can be used to personalized alternative therapy.

Pyroptotic and apoptotic cell death in iNOS and nNOS overexpressing K562 cells: A mechanistic insight

Previous studies from this lab and others have demonstrated that nitric oxide (NO) in a concentration dependent manner, modulated neutrophil and leukemic cell survival. Subsequent studies delineated importance of iNOS in neutrophil differentiation and leukemic cell death. On the contrary, role of nNOS in survival of these cells remains least understood. Present study was therefore undertaken to assess and compare the role of iNOS and nNOS in the survival of NOS overexpressing myelocytic K562 cells. Cells with almost similar iNOS and nNOS activities displayed comparable cell cycle perturbation, Annexin V positivity, mitochondrial dysfunction, augmented DCF fluorescence, and also attenuated expression of antioxidants. Moreover, induction in cell death was also accompanied by the activation of pJNK/p38MAPK/Erk1/2 and reduction in PI3K/Akt/mTOR signaling. Treatment of NOS isoform overexpressing K562 cells with NAC, a potent free radical scavenger prevented cell death and also the modulations in the signaling proteins. In addition, enhanced expression of CASP1 and CASP4 genes, along with increased Caspase-1 cleavage and increased IL-1β release were significantly more in K562^iNOS cells, which indicate priming of these cells for pyroptotic cell death. On the other hand, K562^nNOS cells, displayed much enhanced CASP3 gene expression, Caspase-3 cleavage and Caspase-3 activity. Results obtained indicate that similar level of iNOS or nNOS activation in K562 cells, preferred pyroptotic and apoptotic cell death respectively.

NK-18, a promising antimicrobial peptide: anti-multidrug resistant leukemia cells and LPS neutralizing properties

With the increase of multidrug resistance, novel anti-leukemia agents with diverse mechanisms of action are required to address this challenge. NK-18, the core region of mammalian derived protein NK-lysin, effectively inhibited the viability of both multidrug resistant and sensitive leukemia cell lines. Meanwhile, this proliferation inhibition effect was not distinct between sensitive and multidrug resistant leukemia cell line. NK-18 showed selectivity between non-tumorigenic and tumorigenic cells. It preferentially bound to tumor cells whose outer leaflet with high phosphatidylserine content. NK-18 acted on the multidrug resistant leukemia cell line by a rapid pore formation on the cell membrane, it is not easy for K562/ADM cells developing resistance against NK-18. Furthermore, NK-18 could neutralize lipopolysaccharides by electrostatic attraction and reduce NO production. These research data demonstrated NK-18 possesses great advantage in the multidrug resistant leukemia treatment compared with conventional chemotherapies and it could be a potential candidate for further research.

Anti-apoptotic role of spermine against lead and/or gamma irradiation-induced hepatotoxicity in male rats

Exposure to either lead (Pb) or γ-irradiation (IR) results in oxidative stress in biological systems. Herein, we explored the potential anti-apoptotic effect of spermine (Spm) against lead and/or γ-irradiation-induced hepatotoxicity in male albino rats. Rats were divided into eight experimental groups of ten rats each: groups including negative control, whole body γ-irradiated (6 Gray (Gy)), lead acetate (PbAct) trihydrate orally administered (75 mg/kg bw ≡ 40 mg/kg bw Pb for 14 consecutive days), and Spm intraperitoneally dosed (10 mg/kg bw for 14 consecutive days) rats and groups subjected to combinations of Pb + IR, Spm + IR, Spm + Pb, and Spm + Pb followed by IR on day 14 (Spm + Pb + IR). A significant decrease in arginase activity as well as mRNA and protein levels of Bcl-2 and p21 was observed in rats intoxicated with Pb and/or γ-irradiation compared to controls, whereas Bax mRNA and protein levels were significantly increased. Also, an increased level of nitric oxide (NO) with a reduced arginase activity was observed in liver tissues of intoxicated rats. Spm co-treatment with lead and/or γ-irradiation attenuated the increase in Bax mRNA and protein expression, while it restored those of Bcl-2 and p21 together with NO levels and arginase activity to control values. Altogether, we suggest that Spm may be useful in combating free radical-induced apoptosis in Pb-intoxicated and/or γ-irradiated rats.

Cellular and plasma nitrite levels in myeloid leukemia: a pathogenetic decrease

Nitric oxide (NO) has a contributory role in hemopoietic cell growth and differentiation. The effects of NO on leukemic cell growth have been predominantly studied inin vitrosettings. This study was done to assess the alterations in nitrite level in myeloid leukemias. Thirty-six newly diagnosed cases of myeloid leukemia (16 AML and 20 CML) were enrolled in the study. Neutrophil precursors from the marrow aspirate and peripheral blood were separated into cell bands using the Percoll density gradient method of Borregard and Cowland. The blood plasma and marrow fluid was also collected. Nitrite (stable non-volatile end product of NO) was estimated in the cell bands, blood plasma and marrow fluid using Griess reagent. The mean nitrite level in all cell bands from peripheral blood, bone marrow, blood plasma, and marrow fluid of cases was significantly lower as compared to corresponding value in the controls. No significant difference between AML and CML was seen. On follow-up, analysis of 13 CML patients higher nitrite levels were seen (p>0.05). The significant decrease in nitrite levels in myeloid leukemia suggests a decrease in nitric oxide synthase (NOS) activity. Further work may unfold molecular targets for therapeutic role of NO modulators.

Cisplatin-Induced Nephrotoxicity; Protective Supplements and Gender Differences

Cisplatin (CDDP) has been widely used as a chemotherapeutic agent for solid tumors. The most common side effect of CDDP is nephrotoxicity, and many efforts have been made in the laboratory and the clinic to employ candidate adjuvants to CDDP to minimize this adverse influence. Many synthetic and herbal antioxidants as well as trace elements have been investigated for this purpose in recent years and a variety of positive and negative results have been yielded. However, no definitive supplement has so far been proposed to prevent CDDP-induced nephrotoxicity; however, this condition is gender related and the sex hormone estrogen may protect the kidney against CDDP damage. In this review, the results of research related to the effect of different synthetic and herbal antioxidants supplements are presented and discussed with suggestions included for future work.

Evaluation of INOS, ICAM-1, and VCAM-1 gene expression: A study of adult T cell leukemia malignancy associated with HTLV-1

The main aim of this study was to evaluate the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and inducible nitric oxide synthase (iNOS) as host factors, and proviral load as the viral parameter, in adult T-cell leukemia/lymphoma (ATLL) individuals and healthy carrier (HC(s)) groups. Peripheral blood mononuclear cells (PBMC) from ATLL patients (n = 17) and HC subjects (as the control group, n = 17) were evaluated using real-time PCR to determine the levels of HTLV-1 proviral load and mRNA expression of ICAM, VCAM-1, and iNOS. ICAM-1 was significantly lower in ATLL patients than in control subjects. Although the expression of VCAM-1 was higher in ATLL individuals, there was no significant difference between the studied groups. In addition, no iNOS expression was found in ATLL patients, when compared to the HCs subjects, while ATLL patients demonstrated a higher level of proviral load when compared to the control group. Considering the importance of ICAM-1 in facilitating immune recognition of infected cells, it is posited that reduction of ICAM-1 expression is a unique strategy for circumventing appropriate immune responses that are mediated by different accessory proteins. Additionally, as the viral regulatory protein Tax and the NF-κB pathway play pivotal roles in expression of iNOS, lack of the latter in ATLL patients may be related to the level of Tax expression, disruption of the NF-κB pathway, or the occurrence of epigenetical mechanisms in the human iNOS promoter. Further studies are recommended to gain a better understanding of the interaction between host and viral factors in HTLV-1 pathogenesis and to identify a possible therapeutic target for ATLL.

Urolithin C, a gut metabolite of ellagic acid, induces apoptosis in PC12 cells through a mitochondria-mediated pathway

Urolithin C includes apoptosis in PC12 cells through a mitochondria-mediated pathway.

Anti-tumor and Chemoprotective Effect of Bauhinia tomentosa by Regulating Growth Factors and Inflammatory Mediators

Cancer is a leading cause of death worldwide. Due to the toxic side effects of the commonly used chemotherapeutic drug cyclophosphamide (CTX), the use of herbal medicines with fewer side effects but having potential use as inducing anti-cancer outcomes in situ has become increasingly popular. The present study sought to investigate the effects of a methanolic extract of Bauhinia tomentosa against Dalton's ascites lymphoma (DAL) induced ascites as well as solid tumors in BALB/c mice. Specifically, B. tomentosa extract was administered intraperitonealy (IP) at 10 mg/kg. BW body weight starting just after tumor cell implantation and thereafter for 10 consecutive days. In the ascites tumor model hosts, administration of extract resulted in a 52% increase in the life span. In solid tumor models, co-administration of extract and CTX significantly reduced tumor volume (relative to in untreated hosts) by 73% compared to just by 52% when the extract alone was provided. Co-administration of the extract also mitigated CTX-induced toxicity, including decreases in WBC count, and in bone marrow cellularity and α-esterase activity. Extract treatment also attenuated any increases in serum levels of TNFα, iNOS, IL-1β, IL-6, GM-CSF, and VEGF seen in tumor-bearing hosts. This study confirmed that, the potent antitumor activity of B.tomentosa extract may be associated with immune modulatory effects by regulating anti-oxidants and cytokine levels.

Lophirones B and C prevent aflatoxin B1-induced oxidative stress and DNA fragmentation in rat hepatocytes

Context Despite the reported anticarcinogenic activity of lophirones B and C, no scientific information exists for its activity in rat hepatocytes. Objective Effect of lophirones B and C on aflatoxin B1 (AFB1)-induced oxidative stress, and DNA fragmentation in rat hepatocytes was investigated. Materials and methods Wistar rat hepatocytes were incubated with lophirones B and C (1 mg/mL) or sylimarin (1 mg/mL) in the presence or absence of AFB1. For an in vivo study, rats were orally administered with lophirones B and C, and/or AFB1 (20 μg/d) for 9 weeks. Results Lophirones B and C lowered AFB1-mediated increase in nitric oxide, superoxide anion radicals, caspase-3 and fragmented DNA. Lophirones B and C attenuated AFB1-mediated decrease in superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and reduced glutathione. Also, lophirones B and C attenuated AFB1-mediated increase in conjugated dienes, lipid hydroperoxides and malondialdehyde in rat hepatocytes. Furthermore, AFB1-mediated alterations in alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin, total bilirubin and globulin in rat serum were significantly annulled in lophirones B and C-treated rats. Conclusion This study revealed that lophirones B and C prevented AFB1-induced oxidative damage in rat hepatocytes.

Resveratrol sensitizes glioblastoma-initiating cells to temozolomide by inducing cell apoptosis and promoting differentiation

Glioblastoma-initiating cells play crucial roles in the origin, growth, and recurrence of glioblastoma multiforme. The elimination of glioblastoma-initiating cells is believed to be a key strategy for achieving long-term survival of glioblastoma patients due to the highly resistant property of glioblastoma-initiating cells to temozolomide. Resveratrol, a naturally occurring polyphenol, has been widely studied as a promising candidate for cancer prevention and treatment. Whether resveratrol could enhance the sensitivity of glioblastoma-initiating cells to temozolomide therapy has not yet been reported. Here, using patient-derived glioblastoma-initiating cell lines, we found that resveratrol sensitized glioblastoma-initiating cells to temozolomide both in vitro and in vivo. Furthermore, we showed that resveratrol enhanced glioblastoma-initiating cells to temozolomide-induced apoptosis through DNA double-stranded breaks/pATM/pATR/p53 pathway activation, and promoted glioblastoma-initiating cell differentiation involving p-STAT3 inactivation. Our results propose that temozolomide and resveratrol combination strategy may be effective in the management of glioblastoma patients, particularly for those patients who have been present with a high abundance of glioblastoma-initiating cells in their tumors and show slight responsiveness to temozolomide.

Inducible nitric oxide synthase mediates MG132 lethality in leukemic cells through mitochondrial depolarization

Proteasomes are highly expressed in rapidly growing neoplastic cells and essential for controlling the cell cycle process and mitochondrial homeostasis. Pharmacological inhibition of the proteasome shows a significant anticancer effect on hematopoietic malignancies that is usually associated with the generation of reactive oxygen species. In this study, we comprehensively investigated the role of endogenous oxidants in various cellular events of K562 leukemic cells in response to treatment with MG132, a proteasome inhibitor. MG132 at 1.4 µM potently triggered G2/M arrest, mitochondrial depolarization, and apoptosis. By such treatment, the protein level of inducible nitric oxide synthase (iNOS) was doubled and cellular oxidants, including nitric oxide, superoxide, and their derivatives, were increasingly produced. In MG132-treated cells, the increase in iNOS-derived oxidants was responsible for mitochondrial depolarization and caspase-dependent apoptosis, but was insignificant in G2/M arrest. The amount of iNOS was negatively correlated with that of manganese superoxide dismutase (MnSOD). Whereas iNOS activity was inhibited by aminoguanidine, cellular MnSOD levels as well as mitochondrial membrane potentials were upregulated, and consequentially G2/M arrest and apoptosis were thoroughly reversed. It is suggested that cells rich in functional mitochondria possess improved proteasome activity, which antagonizes the cytotoxic and cytostatic effects of MG132. In contrast to iNOS, endothelial NOS-driven cGMP-dependent signaling promoted mitochondrial function and survival of MG132-stressed cells. In conclusion, the functional interplay of proteasomes and mitochondria is crucial for leukemic cell growth, wherein iNOS plays a key role.

Effects of tyrosine kinase inhibitor E7080 and eNOS inhibitor L-NIO on colorectal cancer alone and in combination

OBJECTIVE

To investigate the effects of E7080 and N (5)-(1-iminoethyl)-L-ornithine dihydrochloride (L-NIO) on colorectal cancer alone and in combination.

METHODS

HT29 colorectal cancer cell line from Sap Institute was used. Real-time cell analysis (xCELLigence system) was performed to determine the effects of E7080 and L-NIO on colorectal cell proliferation. While apoptosis was determined with Annexin V staining, and the effect of agents on angiogenesis was determined with chorioallantoic membrane (CAM) model.

RESULTS

We found that E7080 has a strong antiproliferative effect with an half maximum inhibition of concentration (IC50) value of 5.60×10(-8) mol/L. Also it has been observed that E7080 showed antiangiogenic and apoptotic effects on HT29 colorectal cancer cells. Antiangiogenic scores of E7080 were 1.2, 1.0 and 0.6 for 100, 10 and 1 nmol/L E7080 concentrations, respectively. Furthermore, apoptosis has been detected in 71% of HT29 colorectal cancer cells after administration of 100 nmol/L E7080 which may indicate strong apoptotic effect. Meanwhile administration of L-NIO alone did not show any effect, but the combination of E7080 with L-NIO increased the antiproliferative, antiangiogenic and apoptotic effects of E7080.

CONCLUSIONS

Results of this study indicate that E7080 may be a good choice in treatment of colorectal tumors. Furthermore the increased effects of E7080 when combined with L-NIO raise the possibility to use a lower dose of E7080 and therefore avoid/minimize the side effects observed with E7080.

ROS and RNS induced apoptosis through p53 and iNOS mediated pathway by a dibasic hydroxamic acid molecule in leukemia cells

Anticancer drugs induce apoptosis to cancer cells and also exhibit undesired toxicity to normal cells. Therefore development of novel agents triggering apoptosis and have low toxicity towards normal cells is most important. Hydroxamic acids suppress tumour cell growth through apoptosis but the underlying mechanism is poorly understood. Herein, we describe the apoptotic potential of a dibasic hydroxamic acid derivative, viz., oxayl bis (N-phenyl) hydroxamic acid (OBPHA), which induces apoptosis through generation of both ROS and NO in doxorubicin resistant T-lymphoblastic leukemia, CEM/ADR5000 cells. Present study discloses that OBPHA selectively kills cancerous cells irrespective of their drug resistant phenotype. We also determined the crystal structure of OBPHA to understand the structural requirements for apoptosis; the study reveals that the presence of substituted hydroxamic acid groups (-CO-NH-OH) favours the generation of NO possibly through auto degeneration. Along with the induction of caspase 3 mediated intrinsic apoptosis; OBPHA also activates p53 dependent signalling cascade and downregulates HDAC3 expression in a time dependent manner possibly due to increased ROS and NO production and simultaneous decrease in cellular GSH level. Thus ROS and NO mediated downstream signalling are essential for the anticancer effect of OBPHA. Therefore OBPHA, having a structurally relevant pharmacophore provides important insight into the development of new ROS and RNS generating chemicals inducing p53 dependent apoptosis.

Targeting hepatoma using nitric oxide donor strategies

AIMS

The study evaluated the role of increased intracellular nitric oxide (NO) concentration using NO donors or stably NO synthase-3 (NOS-3) overexpression during CD95-dependent cell death in hepatoma cells. The expression of cell death receptors and caspase activation, RhoA kinase activity, NOS-3 expression/activity, oxidative/nitrosative stress, and p53 expression were analyzed. The antitumoral activity of NO was also evaluated in the subcutaneous implantation of NOS-3-overexpressing hepatoma cells, as well NO donor injection into wild-type hepatoma-derived tumors implanted in xenograft mouse models.

RESULTS

NO donor increased CD95 expression and activation of caspase-8 and 3 in HepG2, Huh7, and Hep3B cells. NOS-3 overexpression increased oxidative/nitrosative stress, p53 and CD95 expression, cellular Fas-associated death domain (FADD)-like IL-1beta converting enzyme (FLICE) inhibitory protein long (cFLIP(L)) and its short isoform (cFLIP(S)) shift, and cell death in HepG2 (4TO-NOS) cells. The inhibition of RhoA kinase and p53 knockdown using RNA interference reduced cell death in 4TO-NOS cells. The supplementation with hydrogen peroxide (H(2)O(2)) increased NOS-3 activity and cell death in 4TO-NOS cells. NOS-3 overexpression or NO donor injection into hepatoma-derived tumors reduced the size and increased p53 and cell death receptor expression in nude mice.

INNOVATION AND CONCLUSIONS

The increase of intracellular NO concentration promoted oxidative and nitrosative stress, Rho kinase activity, p53 and CD95 expression, and cell death in cultured hepatoma cells. NOS-3-overexpressed HepG2 cells or intratumoral NO donor administration reduced tumor cell growth and increased the expression of p53 and cell death receptors in tumors developed in a xenograft mouse model.

Carbonyl group serum levels are associated with CD38 expression in patients with B chronic lymphocytic leukemia

OBJECTIVES

To evaluate carbonyl groups (CG) serum levels in B-chronic lymphocytic leukemia (B-CLL) patients.

DESIGN AND METHODS

CG serum levels were assessed in 48 B-CLL patients and in 30 control subjects.

RESULTS

CG were increased in B-CLL patients. We found a positive correlation between CG with CD38 expression and a negative correlation with ZAP 70 expression.

CONCLUSIONS

B-CLL patients displayed an unbalance of the oxidative stress. CG serum levels could be considered as a prognostic factor in B-CLL.

Widespread deregulation of phosphorylation-based signaling pathways in multiple myeloma cells: opportunities for therapeutic intervention

Multiple myeloma (MM) is a neoplasm of plasma cell origin that is largely confined to the bone marrow (BM). Chromosomal translocations and other genetic events are known to contribute to deregulation of signaling pathways that lead to transformation of plasma cells and progression to malignancy. However, the tumor stroma may also provide trophic support and enhance resistance to therapy. Phosphorylation of proteins on tyrosine, serine and threonine residues plays a pivotal role in cell growth and survival. Therefore, knowing the status of phosphorylation-based signaling pathways in cells may provide key insights into how cell growth and survival is promoted in tumor cells. To provide a more comprehensive molecular analysis of signaling disruptions in MM, we conducted a kinome profile comparison of normal plasma cells and MM plasma cells as well as their surrounding cells from normal BM and diseased BM. Integrated pathway analysis of the profiles obtained reveals deregulation of multiple signaling pathways in MM cells but also in surrounding bone marrow blood cells compared to their normal counterparts. The deregulated kinase activities identified herein, which include the mTOR (mammalian target of rapamycin)/p70S6K and ERK1/2 (extracellular signal-regulated kinases 1 and 2) pathways, are potential novel molecular targets in this lethal disease.

Interferon-γ and nitric oxide production during Behçet uveitis: immunomodulatory effect of interleukin-10

Uveitis is one of the major manifestations of Behçet Disease, a systemic inflammatory vasculitis. Our aim is to investigate in vivo and in vitro production of interferon (IFN)-γ and nitric oxide (NO) during Behçet uveitis (BU). Moreover, we evaluated the implication of IFN-γ and interleukin (IL)-10 in the regulation of NO production in vitro. Cytokines' concentrations were measured by ELISA, and NO levels were assessed by modified Griess's method. Our results showed that patients with active disease had significant elevation of IFN-γ and NO concentrations in both plasma and peripheral blood mononuclear cell culture supernatants compared with controls (P<0.01) or to patients with inactive disease (P<0.05). Further, IFN-γ induced significantly higher production of NO in cell culture supernatants, whereas IL-10 significantly reduced it (P<0.05). In conclusion, the elevated levels of IFN-γ in vivo and in vitro in patients with BU reflect the implication of this cytokine in the disease physiopathology. These results suggest that IFN-γ, through the induction of NO synthase 2 and the production of NO, is implicated in the genesis of the inflammatory process during active BU; whereas IL-10 seems to have protective properties.

Tumor necrosis factor alpha pathways develops liver apoptosis in type 1 diabetes mellitus

We analyzed the contribution of TNF-α intracellular pathway in the development of apoptosis in the liver of streptozotocin-induced diabetic rats. In liver tissue, diabetes promoted a significant increase of TNF-α/TNF-R1, and led to the activation of caspase-8, of nuclear factor kappa B (NFκB), and JNK signaling pathways. The activation of NFκB led to an induction of iNOS and consequent increase in NO production. As a consequence of such changes a significant increase of caspase-3 activity and of apoptotic index were observed in the liver of diabetic animals. Importantly, the treatment in vivo of diabetic rats with etanercept (TNF-α blocking antibody) or aminoguanidine (selective iNOS inhibitor) significantly attenuated the induction of apoptosis by reduction of caspase-3 activity. Overall, we demonstrated that in the diabetes enhances TNF-α in the liver, which may be a fundamental key leading to apoptotic cell death, through activation of caspase-8, NFκB and JNK pathways.

Rapid upregulation of cytoprotective nitric oxide in breast tumor cells subjected to a photodynamic therapy-like oxidative challenge

Many tumor cells produce nitric oxide (NO) as an antiapoptotic/progrowth molecule which also promotes antiogenesis and tumor expansion. This study was designed to examine possible antagonistic effects of endogenous NO on tumor eradication by photodynamic therapy (PDT). Using COH-BR1 breast cancer cells sensitized in mitochondria with 5-aminolevulinic acid (ALA)-generated protoporphyrin IX as a model for ALA-based PDT, we found that caspase-9 activation and apoptotic death following irradiation were strongly enhanced by 1400W, an inhibitor of inducible nitric oxide synthase (iNOS). RT-PCR and Western analyses revealed a substantial upregulation of both iNOS mRNA and protein, beginning ca 4 h after irradiation and persisting for at least 20 h. Accompanying this was a strong 1400W-inhibitable increase in intracellular NO, as detected with the NO probe, DAF-2-DA. Short hairpin RNA-based iNOS knockdown in COH-BR1 cells dramatically reduced NO production under photostress while enhancing caspase-9 activation and apoptosis. These findings suggest that cytoprotective iNOS/NO induction in PDT-treated tumor cells could reduce treatment efficacy, and point to pharmacologic intervention with iNOS inhibitors for counteracting this.

Doxorubicin-induced central nervous system toxicity and protection by xanthone derivative of Garcinia mangostana

Doxorubicin (Dox) is a potent, broad-spectrum chemotherapeutic drug used around the world. Despite its effectiveness, it has a wide range of toxic side effects, many of which most likely result from its inherent pro-oxidant activity. It has been reported that Dox has toxic effects on normal tissues, including brain tissue. The present study tested the protective effect of a xanthone derivative of Garcinia Mangostana against Dox-induced neuronal toxicity. Xanthone can prevent Dox from causing mononuclear cells to increase the level of tumor necrosis factor-alpha (TNFα). We show that xanthone given to mice before Dox administration suppresses protein carbonyl, nitrotyrosine and 4-hydroxy-2'-nonenal (4HNE)-adducted proteins in brain tissue. The levels of the pro-apoptotic proteins p53 and Bax and the anti-apoptotic protein Bcl-xL were significantly increased in Dox-treated mice compared with the control group. Consistent with the increase of apoptotic markers, the levels of caspase-3 activity and TUNEL-positive cells were also increased in Dox-treated mice. Pretreatment with xanthone suppressed Dox-induced increases in all indicators of injury tested. Together, the results suggest that xanthone prevents Dox-induced central nervous system toxicity, at least in part, by suppression of Dox-mediated increases in circulating TNFα. Thus, xanthone is a good candidate for prevention of systemic effects resulting from reactive oxygen generating anticancer therapeutics.

The mechanism of fucoidan-induced apoptosis in leukemic cells: involvement of ERK1/2, JNK, glutathione, and nitric oxide

Fucoidan, a sulfated polysaccharide in brown seaweed, has various biological activities including anti-tumor activity. We investigated the effects of fucoidan on the apoptosis of human promyeloid leukemic cells and fucoidan-mediated signaling pathways. Fucoidan induced apoptosis of HL-60, NB4, and THP-1 cells, but not K562 cells. Fucoidan treatment of HL-60 cells induced activation of caspases-8, -9, and -3, the cleavage of Bid, and changed mitochondrial membrane permeability. Fucoidan-induced apoptosis, cleavage of procaspases, and changes in the mitochondrial membrane permeability were efficiently blocked by depletion of mitogen-activated protein kinase (MAPK) kinase kinase 1 (MEKK1), and inhibitors of MAPK kinase 1 (MEK1) and c Jun NH2-terminal kinase (JNK). The phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and JNK was increased in fucoidan-treated HL-60, NB4, and THP-1 cells, but not K562 cells. ERK1/2 activation occurred at earlier times than JNK activation and JNK activation was blocked by MEK1 inhibitor. In addition, fucoidan-induced apoptosis was inhibited by addition of glutathione and/or L-NAME, and fucoidan decreased intracellular glutathione concentrations and stimulated nitric oxide (NO) production. Buthionine-[R,S]-sulfoximine rendered HL-60 cells more sensitive to fucoidan. Depletion of MEKK1 and inhibition of MEK1 restored the intracellular glutathione content and abrogated NO production, whereas inhibition of JNK activation by SP600125 restored intracellular glutathione content but failed to inhibit NO production in fucoidan-treated HL-60 cells. These results suggest that activation of MEKK1, MEK1, ERK1/2, and JNK, depletion of glutathione, and production of NO are important mediators in fucoidan-induced apoptosis of human leukemic cells.

Pathological, biochemical and haematological investigations on the protective effect of alpha-lipoic acid in experimental aflatoxin toxicosis in chicks

1. The purpose of this study was to investigate the protective effect of alpha-lipoic acid (LA) on aflatoxin (AF) toxicosis in chicks. 2. Groups of 10 Ross PM3 chicks were given, for 21 d, no AF (C), 60 mg/kg/bwt of alpha-lipoic acid (LA), 150 ppb of aflatoxin (AF1), 150 ppb of aflatoxin plus 60 mg/kg/bwt of alpha-lipoic acid (AF1 + LA), 300 ppb of aflatoxin (AF2), and 300 ppb of aflatoxin plus 60 mg/kg/bwt of alpha-lipoic acid (AF2 + LA). Before the animals were killed, blood samples were drawn for haematological analysis, and then tissue samples were collected for histopathological investigation. Immunohistochemical staining was performed against inducible nitric oxide synthase (iNOS) and nitrotyrosine on liver samples. Apoptotic cell death in liver was assessed by in situ TUNEL assay. The malondialdehyde (MDA) and reduced glutathione (GSH) concentrations in liver and kidney were also determined. 3. Hydropic degeneration and occasional necrosis, bile duct hyperplasia and periportal fibrosis were observed in the livers of AF-treated groups. The severity of these changes was reduced in LA-supplemented AF groups. Occasionally, thymic cortical atrophy, lymphoid depletion in spleen and bursa of Fabricius, and degeneration in the kidney tubule epitheliums were detected in AF groups. The severity of these degenerative changes was slightly reduced in LA supplemented groups. 4. There was moderate to strong iNOS and nitrotyrosine immunoreactivity in the livers of AF groups, while decreased immunoreactivity was observed against both antibodies in the LA supplemented groups. Apoptotic cells were numerous in the AF groups, while greatly reduced in LA supplemented groups. 5. In the liver and kidney of AF-treated groups given 300 ppb of aflatoxin, MDA concentrations were increased as GSH decreased, compared to the control group. LA supplementation of AF-treated birds improved the results compared to the AF only groups, however a statistical difference was observed only in liver tissues between AF2 + LA and AF2 groups. Haematological variables showed no differences among the groups. 6. In conclusion, supplementation of feed with the antioxidant LA, might ameliorate the degenerative effects caused by aflatoxin due to lipid peroxidation.

Role of Nrf2-mediated heme oxygenase-1 upregulation in adaptive survival response to nitrosative stress

Nitrosative stress caused by reactive nitrogen species such as nitric oxide and peroxynitrite overproduced during inflammation leads to cell death and has been implicated in the pathogenesis of many human ailments. However, relatively mild nitrosative stress may fortify cellular defense capacities, rendering cells tolerant or adaptive to ongoing and subsequent cytotoxic challenges, a phenomenon known as 'preconditioning' or 'hormesis'. One of the key components of cellular stress response is heme oxygenase-1 (HO-1), the rate limiting enzyme in the process of degrading potentially toxic free heme into biliverdin, free iron and carbon monoxide. HO-1 is upregulated by a wide array of stimuli and has antioxidant, anti-inflammatory and other cytoprotective functions. This review is intended to provide readers with a welldocumented account of the research done in the area of cellular adaptive survival response against nitrosative stress with special focus on the role of HO-1 upregulation, especially through activation of the transcription factor, Nrf2.

GSH-dependent iNOS and HO-1 mediated apoptosis of human Jurkat cells induced by nickel(II)

The molecular mechanisms by which nickel compounds cause immune cytotoxicity are far from understood. Our preliminary data suggested that nickel(II) induced apoptosis in Jurkat cells by mitochondrial pathway, specifically via mitochondrial membrane potential dissipation and antiapoptotic gene bcl-2 down-regulation. The main goal of this study was to further investigate the toxicity of nickel, especially the induction of reactive oxygen species (ROS) on immune cells, which finally induced apoptosis. Nickel was found to induce glutathione (GSH) depletion in a dose- and time-dependent manner. When Jurkat cells were preincubated with antioxidant N-acetylcysteine (NAC), apoptosis was inhibited distinctly, which suggested that ROS played an initial role in nickel immune toxicity. Heme oxygenase-1 (HO-1) and Nitric oxide (NO) which may play an important role in regulatory and protective processes in cells were assayed upon nickel treatment. A significant increase in HO-1 mRNA levels was detected in nickel treated cells. We confirmed that reduction of Nitrate levels in Jurkat cells was due to down-regulation of inducible nitric oxide synthase (iNOS), not endothelial nitric oxide synthase (eNOS). Expression changes of HO-1 and iNOS were markedly blocked when Jurkat cells were preincubated with NAC, suggesting that ROS resulted in HO-1 and iNOS dysfunction in Jurkat cells. We supposed that the immune toxicity of nickel(II) was mainly due to GSH depletion and finally led to apoptosis, probably via changing the expression levels of HO-1 and iNOS in human T lymphocytes.

Oxidative stress by targeted agents promotes cytotoxicity in hematologic malignancies

The past decade has seen an exponential increase in the number of cancer therapies with defined molecular targets. Interestingly, many of these new agents are also documented to raise levels of intracellular reactive oxygen species (ROS) in addition to inhibiting a biochemical target. In most cases, the exact link between the primary target of the drug and effects on cellular redox status is unknown. However, it is important to understand the role of oxidative stress in promoting cytotoxicity by these agents, because the design of multiregimen strategies could conceivably build on these redox alterations. Also, drug resistance mediated by antioxidant defenses could potentially be anticipated and circumvented with improved knowledge of the redox-related effects of these targeted agents. Given the large number of targeted chemotherapies, in this review, we focus on selected agents that have shown promise in hematologic malignancies: proteasome inhibitors, histone deacetylase inhibitors, Bcl-2-targeted agents, and a kinase inhibitor called adaphostin. Despite structural differences within classes of these compounds, a commonality of causing increased oxidative stress exists, which contributes to induction of cell death.

4-arylcoumarin analogues of combretastatins stimulate apoptosis of leukemic cells from chronic lymphocytic leukemia patients

OBJECTIVE

To investigate the proapoptotic capacities of four arylcoumarin analogues of combretastatins on leukemic cells from B-cell chronic lymphocytic leukemia (CLL), a malignancy characterized by apoptosis deficiency.

MATERIALS AND METHODS

The effects of the four compounds on several nuclear, membrane, and mitochondrial events of apoptosis and on expression of proteins controlling the apoptosis were analyzed after treatment of cultured CLL patients' cells.

RESULTS

Treatment with all four compounds resulted in a dose-dependent internucleosomal DNA fragmentation, in stimulation of phosphatidylserine externalization, disruption of the mitochondrial transmembrane potential and caspase-3 activation. DNA fragmentation was prevented in the presence of the pan-caspase inhibitor z-VAD-fmk. Two of the compounds downregulated the expression of Mcl-1, a protein thought to be crucial for the antiapoptotic state in CLL, while Bcl-2 expression was unaffected. No effects were observed on the expression of p27kip1 or the inducible nitric oxide synthase, two proteins, which are constitutively overexpressed by CLL cells and downregulated during the apoptosis induced by other plant-derived molecules (flavopiridol, polyphenols, or hyperforin). This suggests different mechanisms of action for the compounds studied here. Furthermore, normal B lymphocytes from healthy donors appeared less sensitive than CLL cells to the proapoptotic activity of the four compounds.

CONCLUSION

The four arylcoumarin analogues were able to promote the apoptosis of CLL cells ex vivo through the caspase-dependent mitochondrial pathway. Therefore, these compounds may be of interest to develop new therapies of CLL based on apoptosis restoration.

Neuroprotective efficacy and therapeutic window of curcuma oil: in rat embolic stroke model

BACKGROUND

Among the naturally occurring compounds, turmeric from the dried rhizome of the plant Curcuma longa has long been used extensively as a condiment and a household remedy all over Southeast Asia. Turmeric contains essential oil, yellow pigments (curcuminoids), starch and oleoresin. The present study was designed for investigating the neuroprotective efficacy and the time window for effective therapeutic use of Curcuma oil (C. oil).

METHOD

In the present study, the effect of post ischemic treatment of C.oil after ischemia induced by occlusion of the middle cerebral artery in the rat was observed. C.oil (500 mg/kg body wt) was given 4 hrs post ischemia. The significant effect on lesion size as visualized by using diffusion-weighted magnetic resonance imaging and neuroscore was still evident when treatment was started 4 hours after insult. Animals were assessed for behavioral deficit scores after 5 and 24 hours of ischemia. Subsequently, the rats were sacrificed for evaluation of infarct and edema volumes and other parameters.

RESULTS

C.oil ameliorated the ischemia induced neurological functional deficits and the infarct and edema volumes measured after 5 and 24 hrs of ischemia. After 24 hrs, immunohistochemical and Western blot analysis demonstrated that the expression of iNOS, cytochrome c and Bax/Bcl-2 were altered after the insult, and antagonized by treatment with C.oil. C.oil significantly reduced nitrosative stress, tended to correct the decreased mitochondrial membrane potential, and also affected caspase-3 activation finally apoptosis.

CONCLUSION

Here we demonstrated that iNOS-derived NO produced during ischemic injury was crucial for the up-regulation of ischemic injury targets. C.oil down-regulates these targets this coincided with an increased survival rate of neurons.

Flavopiridol-induced iNOS downregulation during apoptosis of chronic lymphocytic leukemia cells is caspase-dependent

We previously reported that flavopiridol-induced apoptosis of B cell chronic lymphocytic leukemia (CLL) patients' cells ex vivo is associated with downregulation of both the inducible nitric oxide (NO) synthase (iNOS) that produces the antiapoptotic molecule NO, and the CDK inhibitor p27kip1 that is thought to block the cell cycle of CLL cells. Here, we show that iNOS downregulation is caspase-dependent and thus can be considered as one of the effector mechanisms of apoptosis, but not a primary triggering event induced by flavopiridol. Furthermore, we also find that this flavone favors the entry into the S and G2 phases of the cell cycle of a subpopulation of the leukemic cells, confirming that flavopiridol might be useful for improving the efficacy of cell cycle-dependent cytostatic agents in the therapy of CLL.

The role of osteopontin in tumor progression and metastasis in breast cancer

The use of cancer biomarkers to anticipate the outlines of disease has been an emerging issue, especially as cancer treatment has made such positive steps in the last few years. Progress in the development of consistent malignancy markers is imminent because advances in genomics and bioinformatics have allowed the examination of immense amounts of data. Osteopontin is a phosphorylated glycoprotein secreted by activated macrophages, leukocytes, and activated T lymphocytes, and is present in extracellular fluids, at sites of inflammation, and in the extracellular matrix of mineralized tissues. Several physiologic roles have been attributed to osteopontin, i.e., in inflammation and immune function, in mineralized tissues, in vascular tissue, and in kidney. Osteopontin interacts with a variety of cell surface receptors, including several integrins and CD44. Binding of osteopontin to these cell surface receptors stimulates cell adhesion, migration, and specific signaling functions. Overexpression of osteopontin has been found in a variety of cancers, including breast cancer, lung cancer, colorectal cancer, stomach cancer, ovarian cancer, and melanoma. Moreover, osteopontin is present in elevated levels in the blood and plasma of some patients with metastatic cancers. Therefore, suppression of the action of osteopontin may confer significant therapeutic activity, and several strategies for bringing about this suppression have been identified. This review looks at the recent advances in understanding the possible mechanisms by which osteopontin may contribute functionally to malignancy, particularly in breast cancer. Furthermore, the measurement of osteopontin in the blood or tumors of patients with cancer, as a way of providing valuable prognostic information, will be discussed based on emerging clinical data.