Moderate Exercise Modulates Tumor Metabolism of Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) stands out for its aggressiveness and accelerated rate of proliferation. Evidence shows that exercise may exert antitumorigenic effects, but the biochemical mechanisms underlying them remain unclear. Our objective was to evaluate the ability of exercise to modulate tumor growth and energy metabolism in an experimental TNBC model. Female BALB/c mice were sedentary or trained for 12 weeks and inoculated with 1 × 104 4T1 cells in the eighth week. Analyzes of macronutrient oxidation, mitochondrial respiration, and expression of genes related to cell metabolism were performed. The results showed that the trained group had a smaller tumor mass and the mitochondria in the tumors presented lower respiratory rates in the state of maximum electron transport capacity. Additionally, the tumors of the exercised group showed a higher expression of genes related to tumor suppressors, while the genes linked with cellular growth were similar between groups. Furthermore, the training modulated the corporal macronutrient oxidation to almost exclusive carbohydrate oxidation, while the sedentary condition metabolized both carbohydrate and lipids. Therefore, the exercise reduced tumor growth, with an impact on mitochondrial and macronutrient metabolism. Our results shed light on the understanding of the antitumorigenic effects of physical exercise, particularly regarding the metabolic transformations in TNBC.

Immunomodulating action of the 3-phenylcoumarin derivative 6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin in neutrophils from patients with rheumatoid arthritis and in rats with acute joint inflammation.

OBJECTIVE: To examine whether free (3-PD-5free) and/or liposomal (3-PD-5lipo) 6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin (3-PD-5) (1) modulate the effector functions of neutrophils from patients with rheumatoid arthritis under remission (i-RA) and with active disease (a-RA), in vitro; and (2) exert anti-inflammatory effect in a rat model of zymosan-induced acute joint inflammation. METHODS AND RESULTS: Incorporation of 3-PD-5 into unilamellar liposomes of soya phosphatidylcholine and cholesterol was efficient (57.5 ± 7.9%) and yielded vesicles with low diameter (133.7 ± 18.4 nm), polydispersity index (0.39 ± 0.06), and zeta potential (- 1.22 ± 0.34 mV). 3-PD-5free (1 µM) and 3-PD-5lipo (3 µM) equally suppressed elastase release and reactive oxygen species generation in neutrophils from healthy subjects and i-RA and a-RA patients, stimulated with immune complexes. 3-PD-5free (20 µM) suppressed the release of neutrophil extracellular traps and chemotaxis in vitro, without clear signs of cytotoxicity. 3-PD-5lipo (1.5 mg/kg, i.p.) diminished joint edema and synovial infiltration of total leukocytes and neutrophils, without changing the synovial levels of TNF-α, IL-1ß, and IL-6. CONCLUSION: Altogether, the results reported herein indicate that 3-PD-5 is a promising modulator of the early stages of acute joint inflammation that can help to diminish not only excessive neutrophil infiltration in the synovia but also neutrophil activation and its outcomes in RA patients.

Incorporation of Baccharis dracunculifolia DC (Asteraceae) leaf extract into phosphatidylcholine-cholesterol liposomes improves its anti-inflammatory effect in vivo.

The aerial parts of Baccharis dracunculifolia (BdE) is used in the Brazilian folk medicine to treat inflammatory conditions. Here we examined the ability of free and liposomal BdE to modulate reactive oxygen species generation in human neutrophils in vitro and zymosan-induced acute joint inflammation in Wistar rats. We prepared biocompatible liposomes of soya phosphatidylcholine and cholesterol with low diameter, homogeneous size distribution, and neutral surface charge. Free BdE decreased joint swelling, total leucocyte and neutrophil infiltration, and the synovial levels of tumour necrosis factor-α and interleukins 6 and 1ß. Incorporation of BdE into liposomes preserved its capacity to inhibit the neutrophil superoxide anion and total reactive oxygen species generation, and improved its anti-inflammatory effect in vivo by decreasing the effective BdE dose by nearly sixfold. The same liposome type lowered the effective dose of caffeic acid by nearly sixteenfold. Therefore, incorporation of BdE into phosphatidylcholine-cholesterol liposomes improves its anti-inflammatory effect.

Heterologous expression of mitochondrial nicotinamide adenine dinucleotide transporter (Ndt1) from Aspergillus fumigatus rescues impaired growth in Δndt1Δndt2 Saccharomyces cerevisiae strain.

Our understanding of nicotinamide adenine dinucleotide mitochondrial transporter 1 (Ndt1A) in Aspergillus fumigatus remains poor. Thus, we investigated whether Ndt1A could alter fungi survival. To this end, we engineered the expression of an Ndt1A-encoding region in a Δndt1Δndt2 yeast strain. The resulting cloned Ndt1A protein promoted the mitochondrial uptake of nicotinamide adenine dinucleotide (NAD+), generating a large mitochondrial membrane potential. The NAD+ carrier utilized the electrochemical proton gradient to drive NAD+ entrance into mitochondria when the mitochondrial membrane potential was sustained by succinate. Its uptake has no impact on oxidative stress, and Ndt1A expression improved growth and survival of the Δndt1Δndt2 Saccharomyces cerevisiae strain.

Influence of FcγRIIIb polymorphism on its ability to cooperate with FcγRIIa and CR3 in mediating the oxidative burst of human neutrophils.

Considering that human neutrophil FcγRIIa and FcγRIIIb receptors interact synergistically with CR3 in triggering neutrophil functional responses, allelic polymorphisms in these receptors might influence such interactions. We assessed whether FcγRIIIb polymorphisms affect FcγR/CR cooperation in mediating the neutrophil oxidative burst (OB), in particular the FcγRIIIb/CR3 cooperation that occurs via lectin-saccharide-like interactions. The OB of human neutrophil antigen (HNA)-1a-, HNA-1b-, and HNA-1a/-1b-neutrophils stimulated with immune complexes, opsonized or not with serum complement, was measured by the luminol-enhanced chemiluminescence assay. Compared with HNA-1a-neutrophils, HNA-1b-neutrophils exhibited reduced FcγR-stimulated OB, but increased FcγR/CR-stimulated OB. It suggests that (i) FcγR and CR cooperate more effectively in HNA-1b-neutrophils, and (ii) the HNA-1b allotype influences the FcγRIIIb cooperation with FcγRIIa, but not with CR3. HNA-1a- and HNA-1b-neutrophils exhibited similar OB responses elicited via CR3 alone or via FcγR/CR-independent pathways. In addition, the level of FcγRIIIb, FcγRIIa, and CR3 expression did not differ significantly among the neutrophil groups studied. Together, these results demonstrate that the HNA-1b allotype influences the functional cooperation between FcγRIIIb and FcγRIIa, and suggest that the difference in the glycosylation pattern between HNA-1a and HNA-1b does not affect the FcγRIIIb cooperation with CR3.

In vitro evaluation of the antioxidant activity of liposomal flavonols by the HRP-H2O2-luminol system.

Considering that antioxidant flavonols have been reported to be beneficial to human health, but that their low water solubility and bioavailability limit their administration through systemic route, the development of suitable flavonol-carriers is of great importance for clinical therapeutics. The aim of this study was to prepare liposomes containing flavonols or not and evaluate their antioxidant activity. Vesicles were obtained by ethanol injection method and characterized in terms of entrapment efficiency, size and zeta potential. Inhibitory activity of liposomal flavonols on reactive oxygen species generation was assessed in vitro using luminol-H(2)O(2)-horseradish peroxidase technique. Antioxidant activity of liposomal flavonols is dependent on concentration and chemical structure of active compound. Quercetin and myricetin are the most active flavonols (IC(50) = 0.6-0.9 µmol/L), followed by kaempferol (IC(50) = 3.0-4.5 µmol/L) and galangin (IC(50) = 4.0-7.0 µmol/L). Our results suggest that antioxidant-loaded liposomes may be promising tools for therapy of diseases where oxidative stress is involved.

Propylthiouracil and thiamazole do not alter in vitro neutrophil oxidative burst.

Propylthiouracil and thiamazole are thionamides used in the treatment of hyperthyroidism. In addition to reducing thyroid hormone synthesis, these drugs have other activities that improve the hypermetabolic state of the patients as well as adverse and toxic effects. The capacity of these 2 drugs to interfere with the production of reactive oxygen species of human neutrophils exposed in vitro to these drugs was evaluated. The production of reactive oxygen species was assessed by chemiluminescence assays and the cells were stimulated with zymosan particles opsonized with a pool of normal human serum. No alteration was found in the chemiluminescence response of treated human neutrophils when compared to controls. The results show that these drugs, at the studied concentrations and with the experimental approach used, have no direct effect on the production of oxidative burst of neutrophils. We conclude that if these drugs have any action on the oxidative metabolism of neutrophils these might include some metabolization steps that do not take place in this in vitro model.

Effect of Tityus serrulatus scorpion venom and its major toxin, TsTX-I, on the complement system in vivo.

The effects of Tityus serrulatus venom and TsTX-I (Ts1 or gamma-toxin) on the lytic activity of the complement system (CS) were investigated in vivo. Serum classical pathway (CP) and alternative pathway (AP) activities were determined in sera of rats (200+/-10 g) injected i.p. with soluble venom (150 microg/kg), TsTX-I (150 microg/kg) or saline (control). The animals were sacrificed 0.5, 1, 2, 4, 24 and 48 h after injection. The results showed an increase in serum lytic activity of animals injected with venom, reaching values up to 70% above controls in CP activity and 120% in AP activity. These effects were biphasic with maximum values 1 and 24 h after venom injection. Similar effects were obtained for TsTX-I, but with lower intensity. Hematocrit values of all tested animals were determined to evaluate the effect of hemoconcentration on the lytic activity of the CS. It was observed that the maximum hematocrit value was obtained 1 h after injection and returned to normal values within 24 h. These data indicate that hemoconcentration can play a relevant role in the first peak of complement activity, but we cannot discard a direct action of the venom on the system during this period, since the serum venom concentration is maximal 15-30 min after envenomation. The high lytic activity of the serum observed after 24 h, period in which the hematocrit values are normal and no venom can be detected, may be consequence of the inflammatory process induced by the venom or toxin. The lytic activity of the serum of rats injected with venom, TsTX-I or saline was abolished when the serum was previously adsorbed on zymosan. These data confirm that the increase of the lytic activity of the serum induced by the venom or toxin is dependent on CS. These results show that CS is involved in the inflammatory process induced by the venom or toxin and consequently in the lung edema, hemolysis, leukocytosis, among other clinical manifestations of severe envenomation.