Oxidative DNA damage induced by ROS-modulating agents with the ability to target DNA: A comparison of the biological characteristics of citrus pectin and apple pectin

DNA targeting anticancer agents have been very successful in clinic, especially, when used in combinatorial therapy. But unfortunately, they often exhibit high levels of toxicity towards normal cells. Hence, much effort has been put into finding agents with more selectivity, and less toxicity. Pectins are natural polysaccharides, and beneficial nutritional fibers that have attracted attentions due to their antitumor properties. However, their molecular targets, and mechanism of action are widely unknown. Here, we have reported that citrus pectin (CP) and apple pectin (AP) selectively suppress viability in MDA-MB-231, MCF-7 and T47D human Breast cancer cells, while non-toxic to L929 normal cells. Upon CP, and AP treatments, cancer cells’ ROS content increased rapidly, and led to the collapse of the mitochondrial transmembrane potential which functions upstream of the caspase-dependent apoptosis. CP and AP treated cancer cells were also arrested at the S and G1 or G2/M phases of the cell cycle, respectively. Furthermore, mRNA expression of Galectin-3 (a multi-functional lectin involved in cell adhesion, cell cycle, and apoptosis) reduced in both CP and AP treated cells. Growth inhibition of MDA-MB-231 cells by CP, and AP was concomitant with DNA damage (oxidation, and strand breaks). In this context, in an effort to clarify the mechanism of action, we showed that CP, and AP are able to interact with DNA. The strength and mode of DNA binding were established by spectroscopy techniques. We demonstrated that CP, and AP bind to dsDNA by intercalation, and groove binding/partial intercalation, respectively. In conclusion, our findings suggest that CP, and AP induce apoptosis in MDA-MB-231 cells by increasing the release of ROS, which may be related to the mitochondrial apoptosis pathway, and direct interactions with DNA. Our data indicate that these compounds may be potentially useful in cancer treatment.

Dominant Th1 cytokine production in early onset of human brucellosis followed by switching towards Th2 along prolongation of disease

Human brucellosis is a worldwide zoonotic infectious disease which is caused by intracellular bacteria belonging to the genus Brucella. Based on murine studies it has been shown that host resistance to Brucella depends on Th1 response, whereas Th2 response is involved in the severity of the disease. Since the immune response during human brucellosis has not been profoundly studied we have tried to evaluate cytokine production in patients suffering from brucellosis. Diluted whole blood samples were cultured in the presence of the mitogen, heat inactivated bacteria or medium alone. IL-12, IFN-gamma and IL-10 were measured by specific sandwich ELISA. In addition, the percentage of CD3(+) T cells producing either IL-13 or IFN-gamma was determined by flow cytometry. It was found that not only IFN-gamma production but also the number of CD3(+) IFN-gamma-producing cells decreased with prolongation of the disease but the percentage of CD3(+) IL-13(+) T cells were significantly increased. No correlation between duration of disease and IL-10 or IL-12 production was found. In conclusion, it is proposed that at the onset of brucellosis, Th1 response dominates while diminishing with prolongation of the disease.

Synthesis and anti-leishmanial activity of 5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-amines containing N-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl] moieties

A novel series of 5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-amines were synthesized by introducing N-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl] moiety as a new functionality on the C-2 amine of thiadiazole ring via click chemistry. The title compounds namely, N-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]-5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-amines (3a-n) were characterized by IR, NMR and MS spectra. These compounds were evaluated for their in vitro anti-leishmanial activity against promostigote form of the Leishmania major. Most compounds exhibited good anti-leishmanial activity against the promastigote form of L. major. The most active compound against promostigotes was found to be 4-methylbenzyl analog 3i, which significantly decreases the number of intracellular amastigotes per macrophage, percentage of macrophage infectivity and infectivity index.

Prevention of immune dysfunction and vitamin E loss by dehydroepiandrosterone and melatonin supplementation during murine retrovirus infection

Female C57BL/6 mice infected with the LP-BM5 leukaemia retrovirus developed murine acquired immune-deficiency syndrome (AIDS). Dehydroepiandrosterone (DHEA) and melatonin (MLT) modify immune dysfunction and prevent lipid peroxidation. We investigated whether DHEA and MLT could prevent immune dysfunction, excessive lipid peroxidation, and tissue vitamin E loss induced by retrovirus infection. Retrovirus infection inhibited the release of T helper 1 (Th1) cytokines, stimulated secretion of Th2 cytokines, increased hepatic lipid peroxidation, and induced vitamin E deficiency. Treatment with DHEA or MLT alone, as well as together, largely prevented the reduction of B- and T-cell proliferation as well as of Th1 cytokine secretion caused by retrovirus infection. Supplementation also suppressed the elevated production of Th2 cytokines stimulated by retrovirus infection. DHEA and MLT simultaneously reduced hepatic lipid peroxidation and prevented vitamin E loss. The use of DHEA plus MLT was more effective in preventing retrovirus-induced immune dysfunction than either DHEA or MLT alone. These results suggest that supplementation with DHEA and MLT may prevent cytokine dysregulation, lipid oxidation and tissue vitamin E loss induced by retrovirus infection. Similarly, hormone supplementation also modified immune function and increased tissue vitamin E levels in uninfected mice.

Coumarin-based bioactive compounds: facile synthesis and biological evaluation of coumarin-fused 1,4-thiazepines

As part of our ongoing studies on the synthesis of bioactive coumarin compounds, we synthesized a series of new coumarin-fused 1,4-thiazepines using a simple method. The biological activity of target compounds along with 3-(2-hydroxybenzylidene)chroman-2,4-dione intermediates was screened by evaluation of their antioxidant and cytotoxic activities. The antioxidant activity was assessed using two methods, namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and ferric reducing antioxidant power (FRAP) assay. 4-Methoxyphenolic compound 5d in thiazepine series showed the most potent scavenging activity, while the 4-bromophenolic derivative 5b was the most efficient compound in FRAP assay. Also, the result of cytotoxic evaluation using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay demonstrated that compound 5b is at least twofold more potent than etoposide against MCF-7, SK-N-MC, and MDA-MB 231 cell lines.

Modulation of cytokine production by dehydroepiandrosterone (DHEA) plus melatonin (MLT) supplementation of old mice

Tissue levels of the antioxidants melatonin (MLT) and dehydroepiandrosterone (DHEA) decline with age, and this decline is correlated with immune dysfunction. The aim of the current study is to determine whether hormone supplementation with MLT and DHEA together would synergize to reverse immune senescence. Old (16.5 months) female C57BL/6 mice were treated with DHEA, MLT, or DHEA + MLT. As expected, splenocytes were significantly (P < 0.05) higher in old mice as compared to young mice. DHEA, MLT, and DHEA + MLT significantly (P < 0.005) increased B cell proliferation in young mice. However, only MLT and DHEA + MLT significantly (P < 0.05) increased B cell proliferation in old mice. DHEA, MLT, and DHEA + MLT help to regulate immune function in aged female C57BL/6 mice by significantly (P < 0.05) increasing Th1 cytokines, IL-2, and IFN-gamma or significantly (P < 0.05) decreasing Th2 cytokines, IL-6, and IL-10, thus regulating cytokine production. DHEA and MLT effectively modulate suppressed Th1 cytokine and elevated Th2 cytokine production; however, their combined use produced only a limited additive effect.

Asymmetrical 2,6-bis(benzylidene)cyclohexanones: Synthesis, cytotoxic activity and QSAR study

In order to develop novel anti-cancer agents, a series of asymmetrical 2,6-bis (benzylidene)cyclohexanone derivatives containing nitrobenzylidene moiety were synthesized and their cytotoxic activity were determined in vitro against MDA-MB 231, MCF-7 and SK-N-MC cell lines using MTT assay. Among the tested compounds, the highest activity against MDA-MB 231 cells was achieved by 2-(3-bromo-5-methoxy-4-propoxybenzylidene)-6-(2-nitrobenzylidene)cyclohexanone (compound 5d). Whereas, compound 5j (the 3-nitro analog of compound 5d) was the most potent compound against MCF-7 and SK-N-MC cell lines. The results indicated that the cytotoxic activity profile against different tumor cells can be optimized by desired 4-alkoxy-3-bromo-5-methoxybenzylidene scaffold.

Isochaihulactone analogues: synthesis and anti-proliferative activity of novel dibenzylbutyrolactones

A series of dibenzyl-γ-butyrolactones bearing a hydroxyl group at the benzylic position of 3-benzyl group were synthesized as hydrated analogue of isochaihulactone and evaluated against breast cancer human cell lines (MDA-M231, MCF-7 and T47D). The target compounds were synthesized in 7 steps from known lactone; (S)-(+)-γ-benzyloxymethyl-γ-butyrolactone. The key step was the aldol condensation between (+)-(R)-β-(benzo[d][1,3]dioxol-5-ylmethyl)-γ-butyrolactone and substituted benzaldehydes which afforded corresponding α-hydroxybenzyl butyrolactone analogues. The cytotoxic study of the synthesized compounds against breast cancer human cell lines showed that some of them inhibit breast cancer human cell proliferation with percentage inhibitions over 50% at concentrations less than 50 μg/mL.

Characterization of a moderate thermophilic Nocardia species able to grow on polycyclic aromatic hydrocarbons

AIMS

Our goal was the characterization of a new moderate thermophilic polycyclic aromatic hydrocarbon (PAH)-utilizing Nocardia strain.

METHODS AND RESULTS

A thermophilic bacterium, strain TSH1, was isolated from a contaminated soil. The macroscopic and microscopic features fit well with the description of Nocardia species. The results of 16S rRNA gene analysis showed 100% match to the type strain of N. otitidiscaviarum DSM 43242(T). Strain TSH1 showed the same mycolic acid pattern as the type strain of N. otitidiscaviarum but its fatty acid profile did not permit identification to the species level. The carbon utilization profile of strain TSH1 was different from N. otitidiscaviarum. The results of hydrophobicity measurements showed that PAHs-grown cells were significantly more hydrophobic than LB-grown cells. Furthermore, biosurfactant production was detected during bacterial growth on different culture media.

CONCLUSIONS

Strain TSH1 is capable of growing on a range of PAHs. When grown in PAHs-supplemented media, strain TSH1 showed a high affinity for the organic phase, suggesting that it can develop a hydrophobic surface.

SIGNIFICANCE AND IMPACT OF THE STUDY

High cell surface hydrophobicity and capability of strain TSH1 to degrade different PAHs at 50 degrees C may make it an ideal candidate to treat PAH-contaminated desert soils.

Monitoring ZEO apoptotic potential in 2D and 3D cell cultures and associated spectroscopic evidence on mode of interaction with DNA

Recognizing new anticancer compounds to improve Breast cancer treatment seems crucial. Essential oil of Zataria Multiflora (ZEO) is a secondary metabolite with some biological properties, yet underlying cellular and molecular anticancer properties of ZEO is unclear. GC/MS analysis revealed that carvacrol is the major ingredient of the essential oil. ZEO increasingly suppressed viability in MDA-MB-231, MCF-7 and T47D Breast cancer cells while nontoxic to L929 normal cells in monolayer cell cultures (2D), whereas MDA-MB-231 multicellular spheroids (3D) were more resistant to inhibition. ZEO significantly induced cell apoptosis confirmed by fluorescent staining, flow cytometry analysis and DNA fragmentation in MDA-MB-231 2D and 3D cell cultures. ZEO increased ROS generation and subsequent loss of ΔΨm, caspase 3 activation and DNA damage which consequently caused G1 and G2/M cell cycle arrest in a dose- and time-dependent manner in 2D. S phase arrest occurred in cell spheroids therefore ZEO possible DNA interaction with gDNA was investigated and revealed ZEO binds DNA via intercalation. Altogether, these data corroborate anticancer properties of ZEO and suggest that cell culture format (2D monolayer vs. 3D spheroid) plays a critical role in drug response and provides new insights into the mechanisms underlying ZEO cytotoxicity effect on Breast cancer cells.

Chitosan promotes ROS-mediated apoptosis and S phase cell cycle arrest in triple-negative breast cancer cells: evidence for intercalative interaction with genomic DNA

Chitosan (CS) is a semi-synthetic bio-based polysaccharide with promising biological and antitumor properties.

Modulation of immune dysfunction during murine leukaemia retrovirus infection of old mice by dehydroepiandrosterone sulphate (DHEAS)

Ageing, leukaemia and acquired immune deficiency syndrome (AIDS) are conditions with dysregulated cytokine production. As dehydroepiandrosterone sulphate (DHEAS) restored normal cytokine production in old mice its effects on retrovirally infected old mice were investigated. Retrovirus infection and ageing-induced immune dysfunction. Murine retrovirus-infected old C57BL/6 female mice consumed 0.22 or 0.44 microgram of DHEAS/mouse/day beginning 2 weeks postinfection for 10 weeks. DHEAS largely prevented the retrovirus-induced reduction in T-cell and B-cell mitogenesis. DHEAS supplement prevented loss of cytokines [interleukin-2 (IL-2) and interferon-gamma] secretion by mitogen-stimulated splenocytes representing T helper 1 (Th1) cell phenotypes. It also suppressed the retrovirus-induced, excessive production of cytokines (IL-6 and IL-10) by Th2 cells. The highest dose of DHEAS reduced IL-6 production by splenocytes from uninfected old mice by 75% while increasing their IL-2 secretion by nearly 50%. Thus immune dysfunction induced by ageing, even when exacerbated by murine retrovirus infection, was largely prevented by DHEAS.

Naphthalene metabolism in Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic microorganism

The thermophilic bacterium Nocardia otitidiscaviarum strain TSH1, originally isolated in our laboratory from a petroindustrial wastewater contaminated soil in Iran, grows at 50 degrees C on a broad range of hydrocarbons. Transformation of naphthalene by strain TSH1 which is able to use this two ring-polycyclic aromatic hydrocarbon (PAH) as a sole source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that strain TSH1 initiates its attack on naphthalene by dioxygenation at its C-1 and C-2 positions to give 1,2-dihydro-1,2-dihydroxynaphthalene. The intermediate 2-hydroxycinnamic acid, characteristic of the meta-cleavage of the resulting diol was identified in the acidic extract. Apart from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as an intermediate for the naphthalene pathway of this Nocardia strain. Neither phthalic acid nor salicylic acid metabolites were detected in culture extracts. Enzymatic experiments with cell extract showed the catechol 1,2-dioxygenase activity while transformation of phthalic acid and protocatechuic acid was not observed. The results of enzyme activity assays and identification of benzoic acid in culture extract provide strong indications that further degradation goes through benzoate and beta-ketoadipate pathway. Our results indicate that naphthalene degradation by thermophilic N. otitidiscaviarum strain TSH1 differs from the known pathways found for the thermophilic Bacillus thermoleovorans Hamburg 2 and mesophilic bacteria.

Stabilization of Zataria essential oil with pectin-based nanoemulsion for enhanced cytotoxicity in monolayer and spheroid drug-resistant breast cancer cell cultures and deciphering its binding mode with gDNA

Efficacy of chemotherapy is limited by the resistance of cancer cells. Phytochemicals especially Essential Oils (EOs) provide an alternative mode of cancer therapy. However, EOs utilization is restricted because of low bioavailability, and high degradation. Nanoemulsification is a method developed to overcome these obstacles. Accordingly, Citrus-Pectin nanoemulsion of Zataria Essential Oil (CP/ZEONE) was prepared to evaluate the anticancer activity and the mechanisms responsible for the caused cytotoxicity. Physical properties and FTIR spectra of CP/ZEONE were characterized. CP/ZEONE progressively improves the suppression of viability of drug-resistant MCF-7, MDA-MB-231 breast cancer cells, and spheroids. It triggers apoptosis by increasing Reactive Oxygen Species (ROS), mitochondrial membrane potential (MMP) loss, DNA damage, G2 and S-phase arrest in MDA-MB-231 cells and spheroids respectively. Additionally, spectroscopy techniques revealed the interaction of CP/ZEONE with DNA via the formation of a groove binding/partial intercalative complex. Thus, ZEO-loaded CP Nano-particles can be further explored as a promising antiproliferative and therapeutic candidate against cancer.

Synthesis and anti-cancer activity evaluation of new dimethoxylated chalcone and flavanone analogs

A novel series of chalcones and flavanones discriminated by the presence of a 3,4-dimethoxyphenyl moiety in their structures were synthesized as anti-cancer agents. The cytotoxicity evaluation of the analogs against the MCF-7, MDA-MB-231 (human breast cancer), and SK-N-MC (human neuroblastoma) cell lines demonstrated that the introduction of a halogen on the 3,4-dimethoxyphenyl part of both series and the attachment of a pyrrolidinylethoxy group on the C-7 position of the flavanone derivatives increased their activity. Indeed, 3-halogenated chalcones (1c and 1d) were more potent than the standard drug etoposide against all tested cell lines. Fluorescence microscopy and flow cytometry analyses confirmed that the anti-cancer effect of the most potent compounds 1c and 1d occurs via apoptosis induction.

Leishmania major lipophosphoglycan: discrepancy in Toll-like receptor signaling

Lipophosphoglycan (LPG) is structurally characterized by a series of phosphoglycan repeat units. Cellular LPG, isolated from promastigotes, has a very similar structure to culture supernatant LPG, but differs in the average number of phosphorylated oligosaccharide repeat units and in glycan composition. Comparison of these LPGs with capillary electrophoresis and immunoblotting indicate that these molecules are highly conserved structurally and composed of galactosylated Gal-Man repeats but their size and molecular weight are very different which is due to glycan portion. There are 30 and 20 repeat units in sLPG and mLPG, respectively. Both LPGs induced nitric oxide in macrophages cell line while sLPG had the higher stimulatory effect. In the presence of anti-TLR2 nitric oxide stimulated by LPG was reduced to control levels. In addition, in the presence of anti-TLR4, nitric oxide stimulated by LPGs was not affected. We propose that lipophosphoglycan induces nitric oxide production via TLR2 signaling pathway.