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1.
J Chromatogr A ; : 460934, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32029268

RESUMO

Peptide-N-glycosidase F (PNGase F) is the most frequently used enzyme to release N-glycan from glycoproteins in glycomics; however, the releasing process using PNGase F is tedious and can range in duration from hours to overnight. Recently, efforts have been made to accelerate this enzymatic reaction, and they include the use of microwave irradiation, ultrahigh pressure, enzyme immobilization, and other techniques. Here, we developed a novel method combining the oriented immobilization of PNGase F on magnetic particles and microwave-assisted enzymatic digestion techniques to achieve highly efficient release of N-glycans. The oriented immobilization of PNGase F on magnetic particles utilizes the affinity of its co-expressed His-tag towards iminodiacetic acid-Nickel modified magnetic particles. Compared with non-oriented immobilization, the oriented immobilization of PNGase F exhibits several advantages including tolerance to high temperature (52 °C) and the ability to retain strong activity after more than five reuses. When used in combination with microwave irradiation, efficient N-glycan removal from ribonuclease B was achieved within 5 min. The proposed strategy was also used to release glycan from fetuin and human serum and has proven to provide a promising deglycosylation method for the characterization of protein glycosylation.

2.
Bioresour Technol ; 303: 122919, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32035388

RESUMO

The addition of biochar derived from different materials can have varying effects on anaerobic digestion (AD), depending on its physicochemical properties. Physicochemical properties of biochars, biomethanization performance and microbial communities were examined to evaluate the effectiveness of biochars made from different plant wastes on AD in this study. Results showed that all biochars significantly reduce the lag phases during AD, compared with a control treatment (CK). Woody biochars particularly performed much better than herbal ones. Correlation analysis revealed that specific surface area (SSA) and electron donating capacity (EDC) were the key properties of the plant-feedstock-derived biochar in AD enhancement. Microbial community structure analysis showed that higher SSA and EDC are conducive for the growth of bacteria decomposing glucose, further promoting daily methane production in the early AD stage. The results indicate that it is important to select biochar with higher SSA and EDC to enhance biomethanization in AD systems.

3.
Anal Chim Acta ; 1098: 56-65, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31948587

RESUMO

RNA molecules carry diverse modifications that exert important influences in many cellular processes. In addition to the single modification occurring in either nucleobase or 2' hydroxyl of ribose in RNA, some dual modifications occur in both the nucleobase and 2' hydroxyl of ribose in RNA. 2'-O-methyl-5-methylcytidine (m5Cm), the dual modifications of cytidine, was first discovered from the tRNA of archaea. Recent studies identified that 2'-O-methyl-5-hydroxymethylcytidine (hm5Cm) and 2'-O-methyl-5-formylcytidine (f5Cm) were present in the anticodon of cytoplasmic tRNA of mammals. Similar to the series of single modification of cytidines of 5-methylcytosine (m5C), 5-hydroxymethylcytidine (hm5C), 5-formylcytidine (f5C), and 5-carboxylcytidine (ca5C) in nucleic acids, the dual modifications of m5Cm, hm5Cm, f5Cm and 2'-O-methyl-5-carboxylcytidine (ca5Cm) may also constitute the series of cytidine modifications in mammals. However, it is normally challenging to detect these modifications because of their low endogenous levels. Here, we established a method by chemical labeling-assisted liquid chromatography - electrospray ionization - tandem mass spectrometry (LC-ESI-MS/MS) analysis for the sensitive and simultaneous determination of all these four cytidine dual modifications, i.e., m5Cm, hm5Cm, f5Cm and ca5Cm. Three different labeling reagents (2-bromo-1-(3,4-dimeth oxyphenyl)-ethanone, BDMOPE; 2-bromo-1-(4-methoxyphenyl)-ethanone, BMOPE; 2-bromo-1-(4-diethylaminophenyl)-ethanone, BDEPE) were used for the chemical labeling. The results showed that the detection sensitivities of m5Cm, hm5Cm, f5Cm and ca5Cm increased up to 462 folds after chemical labeling. With the developed method, we achieved the simultaneous detection of m5Cm, hm5Cm and f5Cm in RNA of mammals. In addition, we found these cytidine dual modifications mainly exist in small RNA (<200 nt) and barely detected in other types of RNA. Moreover, we found that the levels of m5Cm in RNA of human lung carcinoma tissues significantly increased, while hm5Cm and f5Cm significantly decreased compared to tumor adjacent normal tissues. The significant changes of m5Cm, hm5Cm and f5Cm levels may serve as indicator for the detection and prognosis of lung cancer.

4.
Anal Chem ; 92(3): 2612-2619, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31948230

RESUMO

RNA modification, such as N1-methyladenosine (m1A), affects the secondary structure of RNA and its ability to recognize specific reader proteins. Methods for detecting site-specific m1A are in demand. We report here a ligation-assisted differentiation approach for quantitative detection of m1A in mRNA with single-base resolution. The methyl group in m1A disrupts the Watson-Crick base pairing with uridine, resulting in a lower ligation efficiency of certain ligases and lower amounts of ligation products. Detection of the ligation products using quantitative real-time PCR provided site-specific evaluation of m1A. We first screened appropriate ligase and found that T3 DNA ligase offered the best discrimination between m1A and adenosine. We successfully detected and quantified m1A at position 1674 of bromodomain containing 2 (BRD2) mRNA from HEK293T cells. In lung carcinoma tissues, the level of m1A at position 1674 of BRD2 mRNA was significantly decreased compared to the tumor-adjacent normal tissues, suggesting that site-specific m1A may be involved in carcinogenesis.

5.
Artigo em Inglês | MEDLINE | ID: mdl-31900959

RESUMO

BACKGROUND AND AIM: In the phase 3 CONCUR trial (NCT01584830), regorafenib improved overall survival (OS) versus placebo in Asian patients with treatment-refractory metastatic colorectal cancer (mCRC). We conducted a post hoc subgroup analysis of Chinese patients in CONCUR. METHODS: Adults with mCRC progressing despite at least two prior treatment regimens and Eastern Cooperative Oncology Group performance status 0-1 were randomized 2:1 to regorafenib 160 mg once daily or placebo for the first 3 weeks of each 4-week cycle. Dose modifications were permitted. The primary endpoint was OS. Secondary endpoints included progression-free survival, objective overall response, disease control rate, and safety. RESULTS: A total of 172 Chinese patients were randomized and treated (regorafenib n = 112, placebo n = 60). OS was significantly improved with regorafenib versus placebo (8.4 vs 6.2 months, respectively; hazard ratio [HR] 0.56, 95% CI 0.39-0.80; one-sided P = 0.000632), as was progression-free survival (HR 0.32, 95% CI 0.22-0.47; one-sided P < 0.000001). The most common drug-related grade ≥ 3 treatment-emergent adverse events (TEAEs; regorafenib, placebo) were hand-foot skin reaction (19%, 0%), hypertension (13%, 3%), hypophosphatemia (7%, 0%), increased alanine aminotransferase (6%, 0%), and increased aspartate aminotransferase (5%, 0%). In patients receiving regorafenib and placebo, respectively, TEAEs led to treatment discontinuation in 14% and 7%, dose reduction in 39% and 0%, and dose interruption in 64% and 20%. CONCLUSIONS: This retrospective analysis showed that regorafenib provided an OS benefit over placebo for Chinese patients with previously treated mCRC. TEAEs were consistent with the regorafenib safety profile and manageable with treatment modifications.

6.
Eur J Cancer Care (Engl) ; 29(1): e13196, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31825141

RESUMO

BACKGROUND: Using data from the 4-year follow-up results of an open, randomised, phase II study, this patient-based cost-effectiveness analysis compares mFOLFIRI (irinotecan, 5-fluorouracil and leucovorin, the IRI arm) with mFOLFOX7 (oxaliplatin, 5-fluorouracil and leucovorin, the OXA arm) as first-line treatments in patients with locally advanced gastric adenocarcinoma (GC). METHODS: A Markov model was created based on previous results reported at the 2016 Gastrointestinal Cancers Symposium to evaluate mFOLFIRI and mFOLFOX7 for advanced GC quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) were examined as the primary outcomes. RESULTS: For the evaluable 128 patients, treatment efficacy was 0.59 QALYs for the IRI arm and 0.70 QALYs for the OXA arm, with a total cost of $13,861.34 for the IRI arm and $14,127.30 for the OXA arm. Hence, the ICER was $2,417.82 per QALY the OXA arm, which was below the threshold of 3 × per capita GDP of China. For subgroup analysis of those receiving mFOLFIRI followed by mFOLFOX7 (the IRI arm) and the reverse (the OXA arm), the OXA arm gained 0.44 more QALYs than the IRI arm with a total cost of $28,890.09 for the IRI arm and $31,147.30 for the OXA arm. However, the cost per QALY was also lower for the OXA arm than for the IRI arm, and the cost per QALY gained was $5,129.55 (below the Chinese WTP). CONCLUSION: mFOLFOX7 is a very high cost-effective alternative as the first-line treatment for those patients with advanced GC compared with mFOLFIRI.

7.
Mol Cancer Ther ; 19(1): 135-146, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31554653

RESUMO

Both the MAPK pathway and mevalonate (MVA) signaling pathway play an increasingly significant role in the carcinogenesis of colorectal carcinoma, whereas the cross-talk between these two pathways and its implication in targeted therapy remains unclear in colorectal carcinoma. Here, we identified that HMGCS1 (3-hydroxy-3-methylglutaryl-CoA synthase 1), the rate-limiting enzyme of the MVA pathway, is overexpressed in colon cancer tissues and positively regulates the cell proliferation, migration, and invasion of colon cancer cells. In addition, HMGCS1 could enhance the activity of pERK independent of the MVA pathway, and the suppression of HMGCS1 could completely reduce the EGF-induced proliferation of colon cancer cells. Furthermore, we found that trametinib, a MEK inhibitor, could only partially abolish the upregulation of HMGCS1 induced by EGF treatment, while combination with HMGCS1 knockdown could completely reverse the upregulation of HMGCS1 induced by EGF treatment and increase the sensitivity of colon cancer cells to trametinib. Finally, we combined trametinib and dipyridamole, a common clinically used drug that could suppress the activity of SREBF2 (sterol regulatory element-binding transcription factor 2), a transcription factor regulating HMGCS1 expression, and identified its synergistic effect in inhibiting the proliferation and survival of colon cancer cells in vitro as well as the in vivo tumorigenic potential of colon cancer cells. Together, the current data indicated that HMGCS1 may be a novel biomarker, and the combination of targeting HMGCS1 and MEK might be a promising therapeutic strategy for patients with colon cancer.

8.
J Sep Sci ; 43(1): 258-270, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31654552

RESUMO

Microfluidic chip electrophoresis has been widely employed for separation of various biochemical species owing to its advantages of low sample consumption, low cost, fast analysis, high throughput, and integration capability. In this article, we reviewed the development of four different modes of microfluidics-based electrophoresis technologies including capillary electrophoresis, gel electrophoresis, dielectrophoresis, and field (electric) flow fractionation. Coupling detection schemes on microfluidic electrophoresis platform were also reviewed such as optical, electrochemical, and mass spectrometry method. We further discussed the innovative applications of microfluidic electrophoresis for biomacromolecules (nucleic acids and proteins), biochemical small molecules (amino acids, metabolites, ions, etc.), and bioparticles (cells and pathogens) analysis. The future direction of microfluidic chip electrophoresis was predicted.

9.
Anal Chem ; 92(2): 2301-2309, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31845797

RESUMO

Ribonucleotide analogues and their related phosphorylated metabolites play critical roles in tumor metabolism. However, determination of the endogenous ribonucleotides from the complex biological matrix is still a challenge due to their high structural similarity and high polarity that will lead to the low retention and low detection sensitivities by liquid chromatogram mass spectrometry analysis. In this study, we developed the diazo reagent labeling strategy with mass spectrometry analysis for sensitive determination of ribonucleotides in the living organism. A pair of light and heavy stable isotope labeling reagents, 2-(diazomethyl)-N-methyl-N-phenyl-benzamide (2-DMBA) and d5-2-(diazomethyl)-N-methyl-N-phenyl-benzamide (d5-2-DMBA), were synthesized to label ribonucleotides. 2-DMBA showed high specificity and high efficiency for the labeling of ribonucleotides. Our results demonstrated that the detection sensitivities of 12 ribonucleotides increased by 17-174-fold upon 2-DMBA labeling. The obtained limits of detection (LODs) of ribonucleotides ranged from 0.07 fmol to 0.41 fmol. Using this method, we achieved the sensitive and accurate detection of ribonucleotides from only a few cells (8 cells). To the best of our knowledge, this is the highest detection sensitivity for ribonucleotides ever reported. In addition, we found that the contents of almost all of these ribonucleotides were significantly increased in human breast carcinoma tissues compared to tumor-adjacent normal tissues, suggesting that endogenous ribonucleotides may play certain functional roles in the regulation of cancer development and formation. This method also can be potentially applied in the analysis of phosphorylated compounds.

10.
Talanta ; 208: 120484, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816727

RESUMO

Gas embolism is the abnormal emergence of bubble in the vascular system, which can induce local ischemic symptoms. For studying the mechanism underlying gas embolism and revealing local ischemic diseases information, novel technique for analyzing cells response to bubble contact with high controllability is highly desired. In this paper, we present an integrated microfluidic device for the precise generation and control of microbubble based on the gas permeability of polydimethysiloxane (PDMS) to study the effect of bubble's mechanical contact on cells. Cell viability analysis demonstrated that short-term (<15 min) bubble contact was generally non-lethal to cultured endothelial cells. The significant increase in intracellular calcium of the microbubble-contacted cells and cell-to-cell propagation of calcium signal in the adjacent cells were observed during the process of bubble expansion. In addition, the analysis of intercellular calcium signal in the cells treated with suramin and octanol revealed that cell-released small nucleotides and gap junction played an important role in regulating the propagation of calcium wave triggered by bubble contact. Thus, our microfluidic method provides an effective platform for studying the effect of gas embolism on cultured adherent cells and can be further needed for anti-embolism drugs test.

11.
Biochim Biophys Acta Gen Subj ; 1864(3): 129510, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31887339

RESUMO

BACKGROUD: Given the increasing morbidity and mortality of colorectal cancer (CRC), it is urgent to develop a noninvasive screening strategy for early diagnosis of CRC. Altered IgG glycosylation is associated with CRC progression, whereas the association of IgG isomeric glycosylation with CRC were not investigated. METHODS: Methylamidation of IgG N-glycans was conducted prior to PGC-based nanoLC-ESI-MS/MS analysis. Data processing was operated by a self-developed application based on MATLAB solution. Statistical analysis including K-S test, t-test, ROC curve and OPLS-DA were successively performed. Additionally, an independent set was utilized to validate the results. RESULTS: Total 28 IgG glycans and 79 compositional isomers were identified, over half of which are firstly identified so far. Statistical analysis showed that CRC associates with increase in IgG agalactosylation, decrease in IgG sialylation and fucosylation of sialylated glycans. Additionally, it was found that three compositional isomers (H3N4F1-a, H3N4F1-b and H4N3S1F1-e) could distinguish CRC and early stages from controls with an accurate area under the receiver operating characteristic curve. Significantly, these results were validated in an independent set by multivariate statistical analysis. CONCLUSIONS: This is the first comprehensively profiling of isomer-specific IgG N-glycosylation, which could differentiate normal controls from colorectal disease patients. The candidate IgG glyco-biomarkers provide important screening indicators for early diagnosis of CRC. GENERAL SIGNIFICANCE: Colorectal cancer progression is strongly associated with isomer-specific IgG N-glycosylation.

12.
Chem Res Toxicol ; 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31690070

RESUMO

DNA molecules utilize adenine, thymine, cytosine, and guanine for coding genetic information. In addition to these four canonical nucleobases, DNA molecules also contain a variety of modified nucleobases that can control and regulate gene expression and chromosome structure. Elucidating the functions of DNA modifications relies on the sensitive detection, accurate quantification, and genome-wide mapping of these modifications in genomic DNA. The significant advances of techniques and methods in recent years have enabled the discovery and functional studies of a number of new modifications in DNA in both prokaryotes and eukaryotes. Mass spectrometry-based methods for analyzing DNA modifications have substantially advanced over the past decade, which has greatly stimulated the research of DNA epigenetic modifications. The emergence of next-generation sequencing technology provides complementary methodology to enable genome-wide mapping of modifications, which is very important to reveal the biological roles of DNA modifications. This perspective highlights the recent methodologies for the assessment of DNA modifications with focus on mass spectrometry and sequencing analytical strategies.

13.
Horm Cancer ; 10(4-6): 177-189, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31713780

RESUMO

In hepatocellular carcinoma (HCC), the hypoxic tumor microenvironment can drive enhance tumor malignancy and recurrence. The microRNA (miRNA) miR-196-5p has been shown to modulate the progression of several cancer types, but its roles in HCC remain uncertain. In the present report we observed significant miR-196-5p downregulation in HCC tissues and cells, and we found that the expression of this miRNA significantly impaired the proliferation and metastatic potential of HCC in vitro and in vivo. We identified high-mobility group AT-hook 2 (HMGA2) as a miR-196-5p target gene that was associated with the ability of miR-196-5p to modulate the progression of HCC. Expression of miR-196-5p and HMGA2 were correlated with the clinical characteristics and poor outcomes in patients with HCC. Finally, we found that hypoxic conditions were linked with reduced miR-196-5p expression in the context of HCC. Together these results highlight the role for miR-196-5p as an inhibitor of the proliferation and metastasis of HCC via the targeting of HMGA2, with this novel hypoxia/miR-196-5p/HMGA2 pathway serving as a potential target for future therapeutic intervention.

14.
Life Sci ; : 117041, 2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31715188

RESUMO

AIM: The present study explored the role and possible interrelationship between orexin B-sirtuin 1-HIF-1α signaling pathways in diabetes-mellitus induced vascular dysfunction and enhancement in myocardial injury. MATERIAL AND METHODS: Streptozotocin (60 mg/kg) was employed to induce diabetes mellitus in male Wistar albino rats, which were kept for eight weeks. The vascular function was noted by assessing acetylcholine-induced relaxation in norepinephrine precontracted mesenteric arteries. The hearts were subjected to ischemia-reperfusion injury on the Langendorff apparatus. Myocardial injury was assessed by noting the release of CK-MB, cardiac troponin and measuring myocardial infarction. The levels of orexin B, sirtuin 1 and HIF-1α were measured. YNT-185 (orexin B type 2 receptor agonist), STR2104 (sirtuin 1 agonist) and EX527 (sirtuin 1 antagonist) were employed as pharmacological tools. RESULTS: Diabetes led to significant development of vascular dysfunction and enhanced ischemia-reperfusion injury in isolated hearts. There was a significant decrease in the levels of orexin B, sirtuin 1 and HIF-1α in diabetic animals. Treatment with YNT-185 and/or STR2104 significantly attenuated the diabetes-induced increase in myocardial injury and vascular dysfunction. Co-administration of EX527 abolished the effects of YNT-185 suggesting orexin B-mediated effects may be through activation of sirtuin 1. Moreover, YNT-185-induced increase in the expression of sirtuin 1 and HIF-1α was also abolished in the presence of EX527. CONCLUSION: Diabetes-induced significant decline in orexin B levels in the plasma along with a decrease in the expression of sirtuin 1 and HIF-1α in the heart following ischemia-reperfusion injury may possibly contribute in exacerbating the myocardial injury and vascular dysfunction.

15.
Adv Mater ; 31(46): e1905825, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31566283

RESUMO

Synergistic phototherapy has the potential to conquer the extreme heterogeneity and complexity of difficult tumors and result in better cancer treatment outcomes than monomodal photodynamic therapy (PDT) or photothermal therapy (PTT). However, the previous approaches to combining PDT and PTT are mainly focused on primary tumor obliteration while neglecting tumor metastasis, which is responsible for about 90% of cancer deaths. It is shown that a combined PDT/PTT approach, based on upconversion-polymer hybrid nanoparticles with surface-loaded chlorin e6 photosensitizer, can enhance primary tumor elimination and elicit antitumor immunity against disseminated tumors. The specifical arrangement of an external upconversion coating over the polymer core ensures adequate photoabsorption by the upconversion nanoparticles for the generation of reactive oxygen species upon single near-infrared light irradiation. Furthermore, it is found that synergistic phototherapy can elicit robust systemic and humoral antitumor immune responses. When combined with immune checkpoint blockades, it can inhibit tumor relapse and metastasis as well as prolong the survival of tumor-bearing mice in two types of tumor metastasis models. This study may establish a new modality for enhancing immunogenic cell death through a synergistic phototherapeutic nanoplatform and extend this strategy to overcome tumor metastasis with an augmented antitumor immune response.

16.
Environ Sci Technol ; 53(21): 12657-12667, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31549500

RESUMO

The synergistic control of multipollutants is the frontier of environmental catalysis. This research is in the infancy stage, and many uncertainties still remain. Herein, we investigated the reaction characteristics of synergistic elimination of NOx and chloroaromatics on a commercial V2O5-WO3/TiO2 catalyst. The reaction byproducts were qualitatively and quantitatively analyzed, and their origins were clarified. In particular, the origins of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from the synergistic reaction with or without SO2 were first explored; this is crucial for assessing the environmental risk by applying such a synergistic system. Experimental results indicate that during the synergistic reaction, the V2O5-WO3/TiO2 catalyst was deactivated at 200 and 250 °C, whereas the 300 °C was sufficient to durably convert the NO and chlorobenzene at the turnover frequency (TOF) of 7.23 × 10-4 and 1.32 × 10-4 s-1, respectively. A range of aromatics, alkenes, and alkanes, particularly their chlorinated congeners, were observed in the off-gases and on the catalyst surface, where those of 3-chlorobenzonitrile, 4-chloro-2-nitrophenol, and inorganic CS2 were first discovered. In the time-on-stream test at 250 °C, the PCDD/Fs collected from the off-gases was measured at 0.0514 ng I-TEQ Nm-3, but the most toxic dioxins congener, 2,3,7,8-TCDD, was not observed. The alkalinity of selective catalytic reduction reaction likely facilitated the chlorophenol formation, which eventually promoted PCDD/F generation. The SO2 was found to benefit polychlorinated byproduct generation, but the addition of which distinctly inhibited PCDD/F formation.


Assuntos
Dioxinas , Dibenzodioxinas Policloradas , Catálise , Dibenzofuranos , Dibenzofuranos Policlorados
17.
Nat Commun ; 10(1): 4087, 2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31501430

RESUMO

Untethered small actuators have various applications in multiple fields. However, existing small-scale actuators are very limited in their intractability with their surroundings, respond to only a single type of stimulus and are unable to achieve programmable structural changes under different stimuli. Here, we present a multiresponsive patternable actuator that can respond to humidity, temperature and light, via programmable structural changes. This capability is uniquely achieved by a fast and facile method that was used to fabricate a smart actuator with precise patterning on a graphene oxide film by hydrogel microstamping. The programmable actuator can mimic the claw of a hawk to grab a block, crawl like an inchworm, and twine around and grab the rachis of a flower based on their geometry. Similar to the large- and small-scale robots that are used to study locomotion mechanics, these small-scale actuators can be employed to study movement and biological and living organisms.


Assuntos
Biomimética/instrumentação , Grafite/química , Polímeros/química , Pirróis/química , Robótica
18.
Anal Chim Acta ; 1081: 103-111, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31446947

RESUMO

Both DNA cytosine methylation (5-methyl-2'-deoxycytidine, m5dC) and RNA cytosine methylation (5-methylcytidine, m5rC) are important epigenetic marks that play regulatory roles in diverse biological processes. m5dC and m5rC can be further oxidized by the ten-eleven translocation (TET) proteins to form 5-hydroxymethyl-2'-deoxycytidine (hm5dC) and 5-hydroxymethylcytidine (hm5rC), respectively. 2'-O-methyl-5-hydroxymethylcytidine (hm5rCm) was recently also identified as a second oxidative metabolite of m5rC in RNA. Previous studies showed that the dysregulation of cytidine modifications in both DNA and RNA are closely related to a variety of human diseases. These cytidine modifications are generally excreted from cell into urine. If these cytidine modifications exhibit specific features related to certain diseases, determination of the cytidine modifications in urine could be utilized as non-invasive diagnostic of diseases. Here, we established a solid-phase extraction in combination with liquid chromatography-mass spectrometry (LC-MS/MS) analysis for simultaneous detection of these cytidine modifications in human urine samples. The developed method enabled the distinct detection of these cytidine modifications. We reported, for the first time, the presence of hm5rCm in human urine. Furthermore, we found that compared to the healthy controls, the contents of hm5dC, hm5rC, and hm5rCm showed significant increases in urine samples of cancer patients, including lymphoma patients, gastric cancer patients, and esophageal cancer patients. This study indicates that the urinary hydroxylmethylation modifications of hm5dC, hm5rC, and hm5rCm may serve as potential indicator of cancers.


Assuntos
Cromatografia Líquida/métodos , Citidina/análogos & derivados , Citidina/urina , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , DNA/química , Metilação de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , RNA/química
19.
Chem Res Toxicol ; 32(10): 2078-2085, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31433169

RESUMO

Hexavalent chromium [Cr(VI)] compounds that are generated during industrial processes are widely recognized as highly toxic and carcinogenic. It has been reported that exposure to Cr(VI) can produce some chromium intermediates and reactive oxygen species (ROS), which causes DNA damages, genetic instability, and eventually leads to the elevated risk of various diseases including cancers. In recent years, it has been proposed that epigenetic-based mechanisms may involve in the toxic heavy metals-induced cytotoxicity and mutagenicity besides the genetic-based mechanisms. However, whether Cr(VI) could impose its cytotoxic effect through dysregulating the RNA epigenetic modifications remains poorly defined. We systematically investigated the effects of Cr(VI) exposure on 14 kinds of modifications in mRNA of HEK293T cells. We found that Cr(VI) exposure can induce an obvious decrease of inosine in mRNA. In addition, we observed that the expression level of the adenosine deaminase acting on RNA (ADAR1) was significantly decreased upon Cr(VI) exposure, which could be responsible for the induced decrease of inosine in mRNA by Cr(VI) exposure. Together, we demonstrated that Cr(VI) could interrupt A-to-I RNA editing in mRNA, which may eventually lead to the cytotoxicity and mutagenicity.

20.
Langmuir ; 35(34): 11123-11131, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31369286

RESUMO

Three-dimensional porous material holds enormous potential in the field of life science and environmental protection. In this work, we proposed a facile route for the large-scale synthesis of porous poly(dimethylsiloxane) (PDMS) sponge via paraffin oil based emulsion technique. A stable emulsion could be formed by emulsifying water in the PDMS solution with the aid of paraffin oil. Moreover, the amount of emulsified water in 5 g of PDMS solution is as high as 35 g, and the skeleton of the prepared PDMS sponge is still in intact. This method is cost-effective, rapid, and easily scaled up. The water contact angle of the obtained PDMS sponge is 141.9 ± 1°, and the absorption capacities of the sponges are 13.5-33.3 g g-1 for various organic solvents. The PDMS sponge only needed 0.069 MPa force to realize the compression ratio of 90%, which it still maintained after over 50 cycles of compression. In addition, the porous PDMS sponge exhibited an excellent oil absorption and an outstanding reusability, which were potentially useful in water purification.

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