Mn-SOD and CuZn-SOD polymorphisms and interactions with risk factors in gastric cancer

AIM: To investigate the effects of superoxide dismutase (SOD) polymorphisms (rs4998557 , rs4880), Helicobacter pylori (H. pylori ) infection and environmental factors in gastric cancer (GC) and malignant potential of gastric precancerous lesions (GPL). METHODS: Copper-zinc superoxide dismutase (SOD1, CuZn-SOD)-G7958A (rs4998557 ) and manganese superoxide dismutase (SOD2, Mn-SOD)-Val16Ala (rs4880 ) polymorphisms were genotyped by SNaPshot multiplex polymerase chain reaction (PCR) in 145 patients with GPL (87 cases of gastric ulcer, 33 cases of gastric polyps and 25 cases of atrophic gastritis), 140 patients with GC and 147 healthy controls. H. pylori infection was detected by immunoblotting analysis. RESULTS: The SOD1-7958A allele was associated with a higher risk of gastric cancer [odds ratio (OR) = 3.01, 95% confidence intervals (95% CI): 1.83-4.95]. SOD216Ala/Val genotype was a risk factor for malignant potential of GPL (OR = 2.04, 95% CI: 1.19-3.49). SOD216Ala/genotype increased the risk of gastric cancer (OR = 2.85, 95% CI: 1.66-4.89). SOD1-7958A/genotype, SOD2-16Ala/genotype, alcohol drinking, positive family history and type Ⅰ H. pylori infection were associated with risk of gastric cancer, and there were additive interactions between the two genotypes and the other three risk factors. SOD2-16Ala/Val genotype and positive family history were associated with malignant potential of GPL and jointly contributed to a higher risk for malignant potential of GPL (OR = 7.71, 95% CI: 2.10-28.22). SOD1-7958A/genotype and SOD2-16Ala/genotype jointly contributed to a higher risk for gastric cancer (OR = 6.43, 95% CI: 3.20-12.91). CONCLUSION: SOD1-7958A/and SOD2-16Ala/-genotypes increase the risk of gastric cancer in Chinese Han population. SOD2-16Ala/-genotype is associated with malignant potential of GPL.

Visual dual chemodynamic/photothermal therapeutic nanoplatform based on superoxide dismutase plus Prussian blue

Enzyme-based anticancer therapy is more attractive for the less side effect than conventional chemotherapy.However,the poor stability and low membrane permeability of enzymes during the intracellular delivery are constraints for its practical applications.In this work,we synthesized novel near-infrared (NIR)-responsive core-shell-structured Prussian blue@fibrous SiO2 (PBFS) nanoparticles as the carrier of superoxide dismutase (SOD) and a glutathione (GSH)-activated Fenton reagent (DiFe).The PBFS nanoparticles are further modified with aGSH-responsive cationic polymer (poly(2-(acryloyloxy)-N,N-dimethyl-N-(4-(((2-((2-(((4-methyl-2-oxo-2H-chromen-7-yl)carbamoyl)oxy)ethyl)disulfaneyl)ethoxy)carbonyl)amino)benzyl)ethan-1-aminium,PSS) containing disulfide bonds and fluorophores.After SOD and DiFe are loaded on the PBFS-PSS nanoparticles,dual chemodynamic/photothermal therapeutic nanoparticulate systems (PBFS-PSS/DiFe/SOD) are obtained.In vitro experiments show that PBFS-PSS/DiFe/SOD nanoparticles have good biocompatibility and can be tracked under fluorescence microscope during the intracellular delivery process in MCF-7 tumor cells due to the GSH-activated release of fluorophores.They also exhibit high efficiency in NIR photothermal conversion and GSH-activated Fenton reaction in tumor cells,thus achieving high-efficient killing effect of tumor cells based on the combination of photothermal and chemodynamic therapeutic performance (PTT and CDT).This work offers a novel pathway to construct a visual multifunctional nanomedicine platform for future cancer therapy.

A new method of NMR technique in the study of active center structure of metalloenzyme

UP until now, all methods using NMR technique to study the coordinated structure of activecenter in metalloenzyme are to reconstitute the diamagnetic ions [i. e. Zn(Ⅱ), etc.] in metal-loenzyme or its paramagnetic ions [i. e. Cu(Ⅱ), etc] whose electronic relaxation times are notshort enough to substitute the metal ions of active center in enzyme with [Co(Ⅱ), Ni(Ⅱ)],which are paramagnetic and whose electronic relaxation time is shorter, so that the ~1H NMRspectra of the coordinated structure of active center are separated from those of the rest of en-