Iron promotes glycolysis to drive colon tumorigenesis

Colorectal cancer (CRC) is the third most common cancer and is also the third leading cause of cancer-related death in the USA. Understanding the mechanisms of growth and progression of CRC is essential to improve treatment. Macronutrients such as glucose are energy source for a cell. Many tumor cells exhibit increased aerobic glycolysis. Increased tissue micronutrient iron levels in both mice and humans are also associated with increased colon tumorigenesis. However, if iron drives colon carcinogenesis via affecting glucose metabolism is still not clear. Here we found the intracellular glucose levels in tumor colonoids were significantly increased after iron treatment. 13C-labeled glucose flux analysis indicated that the levels of several labeled glycolytic products were significantly increased, whereas several tricarboxylic acid cycle intermediates were significantly decreased in colonoids after iron treatment. Mechanistic studies showed that iron upregulated the expression of glucose transporter 1 (GLUT1) and mediated an inhibition of the pyruvate dehydrogenase (PDH) complex function via directly binding with tankyrase and/or pyruvate dehydrogenase kinase (PDHK) 3. Pharmacological inhibition of GLUT1 or PDHK reactivated PDH complex function and reduced high iron diet-enhanced tumor formation. In conclusion, excess iron promotes glycolysis and colon tumor growth at least partly through the inhibition of the PDH complex function.

Protective Effects of Ammannia baccifera Against CCl4-Induced Oxidative Stress in Rats

Ammannia baccifera Linn. is commonly used as a traditional medicine in India and China. The antioxidant potential of an ethanolic extract of A. baccifera (EEAB; 250 mg/kg and 500 mg/kg) was evaluated against CCL4-induced toxicity in rats. Antioxidant activity was assessed by measuring the enzymatic and non-enzymatic antioxidants. Phytochemical constituents of EEAB were also analyzed by using UHPLC-QTOF-MS. EEAB treatment markedly reduced CCl4 effects on lipid peroxidation, cholesterol, triacylglycerides, and protein carbonyls. It increased the levels of phospholipids, total sulfhydryl, and antioxidant enzymes, which were reduced by CCl4 intoxication. Treatment with EEAB significantly alleviated the CCl4 effect on non-enzymatic antioxidants. Isoenzyme pattern analyses revealed that significant alterations in superoxide dismutase (SOD1), glutathione peroxidase (GPx2, GPx3), and catalase (CAT) occurred in rats that were exposed to CCl4 and restored post EEAB treatment. Moreover, CCl4-induced down regulation of SOD, CAT, and GPx gene expression was conversely counteracted by EEAB. Its bioactivity may be due to its incorporation of major compounds, such as chlorogenic acid, quercetin, protocatechuic acid, lamioside, crocetin, and khayasin C. These results suggest that EEAB may be used as a potent antioxidant and hepatoprotective agent since it is a rich source of flavonoids and phenolic compounds.

Effect of prostatic fluid on the quality of fresh and frozen-thawed canine epididymal spermatozoa

Canine epididymal spermatozoa have a low freeze-tolerance ability compared with ejaculated spermatozoa, which could arise from the absence of prostatic fluid (PF). Therefore, the purpose of this work was to elucidate the influence of PF on the quality of canine epididymal sperm before and after freezing. Caudae epididymides were retrieved from eight dogs after routine castration. Spermatozoa were released by slicing the tissue and were extended in either Tris solution or PF before freezing. Frozen sperm samples were thawed at 70 °C for 8 seconds in a waterbath. Sperm concentration, motility using computer-assisted sperm analysis, morphology, plasma membrane, acrosome and chromatin integrity were assessed in the fresh sperm samples (after 20 minutes incubation) and at 0 and 4 hours after thawing. Progressive motility, distance straight line, distance average path, average path velocity, curvilinear velocity, straight line velocity, straightness, linearity, wobble, and beat cross frequency were significantly increased after extraction into PF. There was a higher proportion of spermatozoa with DNA damage in the PF treatment group at 4 hours after thawing than in the Tris treatment group (15.8% vs. 6.7%, P < 0.05). These results suggest that the addition of PF to canine spermatozoa activates sperm motility in fresh spermatozoa but has a negative effect on chromatin integrity after freezing-thawing.

Protective effect of Actiniopteris radiata (Sw.) Link. against CCl₄ induced oxidative stress in albino rats

ETHNOPHARMACOLOGICAL RELEVANCE

Actiniopteris radiata is a herb with great medicinal value and is evaluated for hepatoprotective activity. To investigate the protective effect of ethanolic extract of Actiniopteris radiata (EEAR) on CCl₄ induced oxidative stress in male Wistar albino rats.

MATERIALS AND METHODS

EEAR were administered for 8 consecutive weeks to rats. Group I - control; Group II - toxin control (30% CCl₄); Group III and Group IV received EEAR (250 and 500 mg/kg respectively). Antioxidant status in liver were estimated by determining the activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx); as well as by determining the levels of lipid peroxidation (LPO) and reduced glutathione (GSH). In addition, isoenzyme pattern and mRNA expression of the antioxidants were studied. Partial characterization of EEAR was performed by Liquid chromatography-mass spectrometry (LC-MS).

RESULTS

CCl₄ induced oxidative stress as evidenced from increase in LPO along with reduction of SOD, CAT, GPx and GSH. Treatment with EEAR (250 and 500 mg/kg) mitigated the CCl₄ induced oxidative stress. An analysis of the isozyme pattern of these antioxidant enzymes revealed variations in SOD2, CAT, GPx2 and GPx3 in CCl₄ treated rats, which were normalized after EEAR treatment. Furthermore, expression of genes for the antioxidant enzymes, were down-regulated by CCl₄ treatment, which were reversed by EEAR. The results of partial characterization of EEAR by LC-MS revealed the presence of rutin and other 7 unknown phenolic derivatives.

CONCLUSIONS

These findings suggest the protective effect of EEAR against CCl₄ induced oxidative stress might be attributed to the presence of flavonoids and phenolic compounds.

Quality of bull spermatozoa after preparation by single-layer centrifugation

The present study aimed to evaluate the effect of single-layer centrifugation (SLC) through a species-specific colloid (Androcoll-B; patent pending, J. M. Morrell) on bull sperm quality. Computer-assisted sperm analysis of motility and flow cytometric analysis of sperm viability (SYBR-14/propidium iodide staining), chromatin integrity (acridine orange staining), reactive oxygen species production [Hoechst 33258-hydroethidine-2',7'-dichlorodihydrofluorescein diacetate (HO-HE-DCFDA) staining], mitochondrial membrane potential (staining with JC-1 probe), and protein tyrosine phosphorylation (specific antibody staining) were performed on unselected and SLC-selected sperm samples. Single-layer centrifugation of bull spermatozoa resulted in the selection of a sperm population that had high mitochondrial membrane potential, a higher content of phosphorylated protein, and more reactive oxygen species than control samples. Sperm chromatin damage was lower in the SLC samples although sperm viability and motility did not differ between SLC samples and controls. These observations suggest that SLC of bull semen in a soybean-containing extender improved some, but not all, parameters of sperm quality.

Activity-guided isolation and identification of anti-staphylococcal components from Senecio tenuifolius Burm. F. leaf extracts

OBJECTIVE

To investigate activity-guided isolation and identification of anti-Staphylococcus aures components from Senecio tenuifolius Burm. F. (S. tenuifolius).

METHODS

Hexane, chloroform, ethyl acetate, methanol and aqueous extracts of S. tenuifolius were prepared by soxilation for antimicrobial activity against one registered Staphylococcus aureus (S. aureus) (ATCC No: 25923) and two clinical isolates, methicillin resistant and methicillin sensitive S. aureus. NCCL standard methods were followed for antibacterial activity. GC-MS was performed to identify the chemical composition of bio active fraction.

RESULTS

Among all solvent extracts, methanol extract significantly reduced the growth of S. aureus (ATCC No: 25923), methicillin resistant and methicillin sensitive S. aureus with the best zone of inhibition at 16.23, 14.06 and 15.23 mm and minimum inhibition concentration (MIC) values at 426.16, 683.22 and 512.12 µg/mL, respectively. In order to detect the active component in methanol extract, it was further purified by column chromatography, which yielded four fractions (St1, St2, St3, and St4). Among these four fractions, St3 was effective against the tested strains of S. aures, with the best zone of inhibition at 15.09, 13.25 and 14.12 mm and with best MIC values at 88.16, 128.11 and 116.12 µg/mL, respectively. Effective fraction partially purified from S. tenuifolius (St3) yielded MIC's that were at least 20 fold less when compared to crude extract. GC-MS analysis of St3 revealed the presence of 3-[methyl-6,7-dihydro benzofuran-4 (5H)-one], 1,2-benzenedicarboxylic acid, hydroquinone, methyl ester and 3 unknown compounds.

CONCLUSIONS

The study provides scientific evidence for traditional and folklore medicinal use of S. tenuifolius in skin infections treatment.