MiR-153-5p promotes sensibility of colorectal cancer cells to oxaliplatin via targeting Bcl-2-mediated autophagy pathway.

Oxaliplatin (L-OHP) is one of the effective chemotherapeutic drugs for colorectal cancer (CRC). Further investigation into the molecular mechanism of chemoresistance could improve outcomes for patients with colorectal cancer. Recently, microRNAs have been reported as a key in drug resistance of tumors. In this study, we aimed to investigate the effects of miR-153-5p in L-OHP-resistant CRC cells, and its underlying mechanism. Downregulation of miR-153-5p was observed in CRC cells, while upregulation of miR-153-5p enhances the chemosensitivity of CRC/L-OHP cells. The autophagy of CRC/L-OHP cells was markedly increased after exposure to L-OHP but abolished by the upregulation of miR-153-5p. Dual-luciferase reporter assays validated that Bcl-2 was a direct target of miR-153-5p. In conclusion, our data suggested that miR-153-5p was a mediator of cisplatin resistance in colorectal cancer by affecting Bcl-2-mediated autophagy, indicating a new therapeutic target for CRC treatment.

Beta-cyclodextrin-centered star-shaped amphiphilic polymers for doxorubicin delivery.

AIM: Delivery of doxorubicin could be achieved by a novel micellar system based on beta-cyclodextrin-centered star-shaped amphiphilic polymers (sPEL/CD). This study specifically explored the effect of polylactide segments in sPEL/CD on various micelle properties, such as the critical micelle concentration, size, drug loading, cytotoxicity and drug resistance reversing effect. METHOD: The sPEL/CD was synthesized by the arm-first method. The critical micelle concentrations of polymeric micelles were determined by fluorescence spectrophotometry using pyrene as a probe. The oil/water method was applied to prepare doxorubicin-loaded micelles. 3-(4,5-dimethylthi-azol-2-yl)-2,5-diphenyltetrazolium bromide, confocal laser-scanning microscopy and flow cytometry were used to examine cell cytotoxicity and cellular uptake of the doxorubicin-loaded micelles. Finally, rhodamine-123 cellular uptake was determined to evaluate the polymer action on MCF-7 and MCF-7/ADR cells. RESULTS: All polymers exhibited low cytotoxicity and their micelles had a desirable release-acceleration pH (pH 5.0) for cytoplasmic drug delivery. With the introduction of polylactide into the polymer, the micelle critical micelle concentration can be effectively decreased and the drug-loading content was enhanced. Most importantly, the drug resistance of MCF-7/ADR cells was significantly reversed via the interaction between polymer and Pgp. Therefore, this type of polymer has potential superiority for cancer therapy.

[Control of shortcut nitrification in SBBR with adequate oxygen supply].

At the high level of dissolved oxygen (DO) in sequencing batch biofilm reactor (SBBR), the approach and mechanism for realizing shortcut nitrification were researched. Landfill leachate was used as handling of object, the mainly environment parameters of the reactor were controlled as follow: DO 5 mg/L, pH 7.0, temperature 25 degrees C, adopted all drainage mode and 12-hour cycle influent. Through mathematical derivation and modeling analysis, determined free ammonia (FA), CO2 and HNO2 as the direct control factors, whereas the influent cycle time was the indirect one, shortcut nitrification was achieved effectively in SBBR. When the volume load of ammonia (NH4(+) -N) was 0.52 kg/(m3 x d) and NaHCO3 was 1.5 mg/L in the reactor, the shortcut nitrification effect was apparent as NH4(+) -N conversion rate was 89% and NO2(-) -N accumulation rate achieved 83% at the same time. With adequate oxygen supply, the key factors of achieving NO2(-) -N accumulation is FA concentration, and as the carbon source of ammonia-oxidizing bacteria, CO2 can upgrade the reactor performance further.

[Approaches of biological nitrogen removal in a single sequencing batch biofilm reactor].

The conventional microorganism techniques and the molecule biological techniques such as PCR and DGGE were utilized to study the approaches of biological nitrogen removal in a single sequencing batch biofilm reactor (SBBR). The main approach of biological nitrogen removal, no less than 65% of the total NH4(+)-N was removed in this approach, was composed of partial nitrification, anaerobic ammonium oxidation and denitrification. The second approach included twain processes such as partial nitrification and denitrification, and the third one was conventional nitrogen removal process (nitrification and denitrification). All approaches accomplished simultaneously or asynchronously. When the approach occurred in the simultaneous way, it performed as nitrogen-loss. The accomplisher of asynchronous way depended on the microbe's different activity between aerated phase and anaerobic phase. First, ammonia was converted to nitrite in the aerated phase when the nitrite bacteria performed high activity, and then anaerobic phase was operated in turn when the denitrifying bacteria and the anammox bacteria eliminated the nitrogen form gases.

[Flocculating capability and mechanism of bioflocculant produced by Paenibacillus polymyxa GA1].

MBFGA1, which was produced by Paenibacillus polymyxa GA1, was used to investigate its flocculating capability in the following waste water, the liquid of kaolin, soil suspended liquid, coal-washing wastewater and the landfill leachate with orthogonal experiments, the inspection of granularity and the scanning electron microanalysis. Meanwhile the anthrone reaction and infrared spectrum are also applied to identify its main component. In the optimal flocculating conditions obtained from the orthogonal experiments, the flocculating rates of the liquid of kaolin, soil suspended liquid, coal-washing wastewater and the landfill leachate were 99.53%, 99.50%, 98.2% and 75.60%, respectively, and the sedimentation velocities of the above four kinds of flocculants were 0.03 m/s, 0.025 m/s, 0.025 m/s and 0.005 m/s, respectively. In addition, the distribution of granularity has changed after flocculation. The size of the average granularity of soil became bigger after flocculation, and reached over 10 microm, but for the other three kinds of granularity just the opposite phenomenon has occurred, and their sizes were all less than 10 microm. From the photos of scan electron microanalysis of four types of granules, it could be drawn that there were no obvious differences in the appearance. It was the same adsorptive mode between MBFGA1 and different flocculating particles, that is the function of electrovalent bond, tested by EDTA, HC1 and urea. The main component of MBFGA1 was polysaccharide, which was determined by anthrone reaction, and it contained a lot of carboxyl and hydroxyl groups examined by infrared spectrum analysis. From the above results, it could be presumed that MBFGA1 can be the best flocculant for the granule-highly-concentrated waste water and the dominative flocculating mechanism of the flocculant was mechanism of adsorption-bridge.

[Bacterial diversity in sequencing batch biofilm reactor (SBBR) for landfill leachate treatment using PCR-DGGE].

For studying the bacterial diversity and the mechanism of denitrification in sequencing bath biofilm reactor (SBBR) treating landfill leachate to provide microbial evidence for technique improvements, total microbial DNA was extracted from samples which were collected from natural landfill leachate and biofilm of a SBBR that could efficiently remove NH4+ -N and COD of high concentration. 16S rDNA fragments were amplified from the total DNA successfully using a pair of universal bacterial 16S rDNA primer, GC341F and 907R, and then were used for denaturing gradient gel electrophoresis (DGGE) analysis. The bands in the gel were analyzed by statistical methods and excided from the gel for sequencing, and the sequences were used for homology analysis and then two phylogenetic trees were constructed using DNAStar software. Results indicated that the bacterial diversity of the biofilm in SBBR and the landfill leachate was abundant, and no obvious change of community structure happened during running in the biofilm, in which most bacteria came from the landfill leachate. There may be three different modes of denitrification in the reactor because several different nitrifying bacteria, denitrifying bacteria and anaerobic ammonia oxidation bacteria coexisted in it. The results provided some valuable references for studying microbiological mechanism of denitrification in SBBR.