The SNHG16/miR-30a axis promotes breast cancer cell proliferation and invasion by regulating RRM2

Long noncoding RNAs (lncRNAs) have been suggested to play vital roles in tumor initiation and progression. Recent studies have reported that the lncRNA small nucleolar RNA host gene 16 (SNHG16) is highly expressed in breast cancer tissue. In the present study, we demonstrated that SNHG16 is an oncogene involved in cell proliferation and invasion in breast cancer. First, we examined the functional role of SNHG16 in breast cancer cells by knocking down SNHG16 expression via siRNA. We found that SNHG16 inhibition reduced the proliferation and invasion of breast cancer cells in vitro. Then, based on bioinformatic prediction and functional assay validation, we demonstrated SNHG16 interaction with miR-30a and its role in breast cancer cells. Finally, we examined the functional role of RRM2 in breast cancer cells by knocking down RRM2 expression via siRNA. Our results indicated that the SNHG16/miR-30a axis regulated the expression of ribonucleotide reductase M2 (RRM2) in breast cancer cells. These results provide novel insight into breast cancer tumorigenesis and suggest that SNHG16 could serve as a therapeutic target in breast cancer.

[Summary and evaluation on methods of water-intake survey among population]

At present, methods of water-intake survey include government, industry, sector statistics data, dietary survey (24 hours dietary recall, dietary record and food frequency questionnaire), fluid intake survey (retrospective fluid-intake questionnaire, 1-5 days 24 hours fluid-intake survey, 7 days 24 hours fluid-intake record), weighing method with the food composition table, weighing method, duplicate portion method and chemical analysis, and so on. The method of 7 days 24 hours fluid-intake record is an internationally recognized and authoritative method for fluid-intake survey with the highest accuracy, which can reflect the differences of fluid intake between working and non-working days, and can obtain detailed data on behaviors and patterns of fluid water, such as the time, types and places of fluid intake. The method of combining weighing method, duplicate portion method and chemical analysis is used to analyze water intake from food with the highest accuracy, which can be used in an extensive range of population and areas, but with high cost and complex operating steps. It is of great practical significance to compare and evaluate the advantages and disadvantages of different methods about water-intake survey, which will be helpful for researchers to choose appropriate methods for water-intake survey to obtain accurate and representative data in various areas, different population, and complex circumstances.

[The clinical efficacy of coblation tonsillectomy and conventional tonsillectomy in China: A Meta analysis]

Objective:To systematically review the clinical efficacy of coblation tonsillectomy and conventional tonsillectomy in China. Method:Randomized controlled trials (RCT) of coblation tonsillectomy and conventional tonsillectomy were searched and retrieved through online databases (PubMed, Cumulative Index to Nursing and Allied Health, EMBASE, Cochrane Library, CBM, CNKI, VIP, WanFang, SUMsearch and Google search engine) and related literatures were reviewed up to 30 April, 2017. Two investigators independently screened literatures,extracted data and evaluated the risk of bias assessment tools for RCT using the Version 5.1.0 of Cochrane Handbook for Systematic Reviews of Interventions. Then, Meta analysis was performed using RevMan 5.3 software provided by the Cochrane Collaboration. Result:A total of 32 RCTs involving 3 197 tonsillectomy patients were included. The results of meta-analysis showed that: the operation time (MD=-17.03, 95%CI -19.78 to -14.28, P＜0.00 001), intraoperative blood loss (MD=-27.00, 95%CI -30.44 to -23.56, P＜0.00 001), postoperative pain in 24 hours (MD=-2.00, 95%CI -2.65 to -1.35, P＜0.00 001), time needed to regain the normal diet (MD=-2.01, 95%CI -2.60 to -1.42, P＜0.00001), formation time of white membrane (MD=-2.44, 95%CI -3.96 to -0.93, P=0.002) of patients in the coblation tonsillectomy group were all significantly lower than the conventional tonsillectomy group; while the exfoliation time of white membrane (MD=2.02, 95%CI 0.65 to 3.39, P=0.004) in the coblation tonsillectomy group was significantly longer than the conventional tonsillectomy group. Conclusion:Current evidence shows that, compared with the conventional tonsillectomy group, the coblation tonsillectomy group can significantly shorten the operation time, decrease intraoperative blood loss, alleviate postoperative pain degree during 24 hours, regain the normal diet early and form white membrane early, but delaye the exfoliation time of white membrane. Due to the limited kinds of literature and quality of the included studies, the above conclusions still need to be verified by carrying out more large scale samples and high quality randomized controlled trials (RCTs) studies.

Expression of microRNA-210 in tissue and serum of renal carcinoma patients and its effect on renal carcinoma cell proliferation, apoptosis, and invasion

This study investigated the expression of microRNA-210 (miR-210) in tissue and serum of renal carcinoma patients and its effect on renal carcinoma cell proliferation, apoptosis, and invasion. Thirty-two renal carcinoma patients in our hospital were selected as the study group and 32 people receiving a physical examination were selected as the control group. miR-210 expression in the serum of renal carcinoma patients and in healthy subjects was quantified by real-time polymerase chain reaction. After miR-210 overexpression and inhibition in ACHN cells in human renal carcinoma, ACHN cell proliferation, apoptosis, and invasion were detected by CCK-8, flow cytometry, and a transwell invasion assay. The expression of miR-210 was significantly higher in renal carcinoma than in corresponding paracarcinoma tissues (P < 0.001). The expression of miR-210 was significantly higher in the serum of renal carcinoma than in the control group (P < 0.001). ACHN cell proliferation and invasion were significantly increased and apoptosis was significantly decreased (P < 0.05) when miR-210 was overexpressed. ACHN cell proliferation and invasion were significantly decreased and apoptosis was significantly increased (P < 0.05) when miR-210 was inhibited. In conclusion, miR-210 was highly expressed in tissues and serum of renal carcinoma patients. miR-210 could promote the proliferation and invasion of renal carcinoma cells and inhibit the apoptosis of renal cell carcinoma cells.

[Gas chromatography for measurement of chlorpyrifos in serum]

OBJECTIVE

To investigate the method for the measurement of chlorpyrifos in serum by gas chromatography, and to provide a basis for emergency treatment of poisoning in clinical practice.

METHODS

Venous blood (3.0 ml) was collected from patients. After coagulation, the blood samples were centrifuged at 4 000 r/min for 5 minutes, and 0.5 ml of serum was placed in a glass test tube with a cork; 4.0 ml of ethyl acetate was then added and mixed rapidly, and this solution was subjected to extraction for 5 minutes and centrifuged at 4 000 r/min for 10 minutes. The ethyl acetate layer was placed in a conical tube and extracted twice with the same method. The extract was mixed and blow-dried with nitrogen, and the residue was dissolved with 50.0 μl ethanol. Gas chromatography was used for measurement, with a sample size of 1 μl and a retention time of 9.609 minutes.

RESULTS

The linear range of this method was 0.2~20.0 μg/ml, and the regression equation was y=2 372.6x+357.2(r=0.999 6). The detection limit of chlorpyrifos in serum was 0.05 μg/ml, and the recovery rate was 84.6%~102.4%. The relative standard deviation was 3.6%~4.8%, and the intra-day and inter-day relative standard deviations were 3.62%~5.10% and 3.77%~4.98%, respectively.

CONCLUSION

This detection method is accurate, simple, and convenient, and can be used for the clinical diagnosis of chlorpyrifos poisoning.

The JAK2/STAT3 and mitochondrial pathways are essential for quercetin nanoliposome-induced C6 glioma cell death

The formulation of quercetin nanoliposomes (QUE-NLs) has been shown to enhance QUE antitumor activity in C6 glioma cells. At high concentrations, QUE-NLs induce necrotic cell death. In this study, we probed the molecular mechanisms of QUE-NL-induced C6 glioma cell death and examined whether QUE-NL-induced programmed cell death involved Bcl-2 family and mitochondrial pathway through STAT3 signal transduction pathway. Downregulation of Bcl-2 and the overexpression of Bax by QUE-NL supported the involvement of Bcl-2 family proteins upstream of C6 glioma cell death. In addition, the activation of JAK2 and STAT3 were altered following exposure to QUE-NLs in C6 glioma cells, suggesting that QUE-NLs downregulated Bcl-2 mRNAs expression and enhanced the expression of mitochondrial mRNAs through STAT3-mediated signaling pathways either via direct or indirect mechanisms. There are several components such as ROS, mitochondrial, and Bcl-2 family shared by the necrotic and apoptotic pathways. Our studies indicate that the signaling cross point of the mitochondrial pathway and the JAK2/STAT3 signaling pathway in C6 glioma cell death is modulated by QUE-NLs. In conclusion, regulation of JAK2/STAT3 and ROS-mediated mitochondrial pathway agonists alone or in combination with treatment by QUE-NLs could be a more effective method of treating chemical-resistant glioma.

Topological transformations of synthetic DNA knots

Two synthetic DNA molecules that can be knotted have been employed as substrates for E. coli DNA topoisomerases I and III. Both molecules contain 104 nucleotides, including sequences that can form two single-turn helical domains, connected by single-stranded oligo(dT) linkers in an X-Y-X'-Y' pairing motif. One of the knots can be ligated to form cyclic molecules with the topologies of a circle, a trefoil knot with negative nodes, or a figure-8 knot. Cyclic molecules constructed from the other molecule can form a circle, a figure-8 knot, and trefoil knots with either positive or negative nodes. The topologically negative nodes in these knots are derived from right-handed B-DNA, and the positive nodes are derived from left-handed Z-DNA. The topoisomerases can catalyze the interconversion of the different topological forms of these molecules, as a function of solution conditions and the extent to which they favor B-DNA or Z-DNA. The enzymes appear to catalyze a single strand-passage event at a time. The topoisomerases can catalyze strand passage events involving both positive and negative nodes as substrates. Gel retention experiments show that both knots can bind up to four molecules of E. coli DNA topoisomerase I. The thermal denaturation of the domains of a trefoil knot closely related to these knots suggests that the two helical domains are uncoupled, so the single-stranded linkers in the knots are not taut. Chemical ligation experiments yield a distribution of products similar to those of enzymatic ligation, showing that the ATP cofactor in DNA knot ligation does not appear to skew the products markedly. Knots that are stressed by being placed in unfavorable solution conditions have been shown to be a highly sensitive system for detecting topoisomerase activity.

The construction of a trefoil knot from a DNA branched junction motif

A DNA trefoil (3(1)) knot has been constructed from a 104-nucleotide molecule whose strands form a 3-arm branched junction motif. This construction tests the notion that a node in a DNA knot can be equated with a half-turn of double-helical DNA, and is consistent with that concept. Of five 104-mer sequences tested, only one produces high yields of the target knot. The other molecules produce larger quantities of circular material and of a knot containing more nodes. The key features that differentiate the successful design from the others are (1) the ligation takes place in the linker region between helical domains and (2) only six nucleotide pairs are used for each of the double-helical arms of the junction. The successful design separates the double-helical regions from each other by a spacer containing two deoxythymidine nucleotides at the site of the branched junction.

A scanning tunnelling microscopy study of the formation and chemical activation of step defects on the basal plane of pyrolytic graphite

Scanning tunnelling microscopy is used to monitor etching of the basal plane of highly orientated pyrolytic graphite by ozone, oxygen and nitric acid. These treatments are seen to produce numerous single and multilayer step defects. Subsequent modification of the graphite sheet edges flanking these cavities by cyanuric chloride, TiCl4 and other reagents is shown to activate the edges, thereby making them capable of covalently binding various molecules.

Tight single-stranded DNA knots

Trefoil (3(1)) and figure-8 (4(1)) knots have been synthesized from DNA molecules containing two single-turn helical domains, linked by four oligodeoxythymidine linkers. Both topologies are derived from the same DNA molecule. The tightest knots are fashioned by minimizing the lengths of the linkers. The shortest equal-length linkers from which a trefoil knot can be made readily are seven nucleotides long, in a 74-nucleotide molecule, whereas those in the shortest figure-8 knot are six nucleotides long, in a 70-nucleotide molecule. In addition to these limiting knots, other knots containing 80, 88, 96 and 104 nucleotides have been constructed. The mobilities of these molecules on denaturing gels show the conventional logarithmic dependence on length. Ferguson analysis of their mobilities indicates a linear dependence of surface area on length. The 80-mer trefoil knot is the tightest molecule that can be restricted in both domains.

DNA junctions, antijunctions, and mesojunctions

Antijunctions and mesojunctions are new classes of multistranded DNA complexes. They represent a generalization of DNA branched junction complexes, such as the Holliday recombination intermediate. Each strand of a conventional branched junction participates in two different double helices, and this is also true for mesojunctions and antijunctions. The helix axes of conventional branched junction complexes may be drawn to converge at a point, but this convergence occurs for lines drawn perpendicular to the helix axes of antijunctions. Mesojunctions are complexes that mix these features of junctions and antijunctions. Antijunction complexes require an even number of strands. We have synthesized the mesojunction containing three strands, the two mesojunctions containing four strands, and the antijunction containing four strands; we compare them with branched junctions containing three and four strands, derived by permutations of the same sequences. Each double helix is designed to contain 1.5 turns of DNA. A tendency to oligomerize makes it difficult to capture antijunctions and mesojunctions in stable discrete complexes, in contrast to conventional branched junctions. For both three-strand and four-strand complexes, Tm is highest for conventional branched junctions. Ferguson analysis indicates similarities in the occluded surface area of junctions, antijunctions, and one four-strand mesojunction, but the other four-strand mesojunction has a much lower apparent surface area. Hydroxyl radical cleavage patterns suggest that the four-strand antijunction and the low-surface-area four-strand mesojunction form stacking domains, analogous to the behavior of conventional branched junctions. These new structures are related to replicational and recombinational intermediates and to single-stranded nucleic acid knots.