Chemiluminescent Kit Research Articles

Sensitive aptasensing of ATP based on a PAM site-regulated CRISPR/Cas12a activation.

The combination of CRISPR/Cas12a and functional DNA provides the possibility of constructing biosensors for detecting non-nucleic-acid targets. In the current study, the duplex protospacer adjacent motif (PAM) in the activator of CRISPR/Cas12a was used as a molecular switch, and a sensitive adenosine triphosphate (ATP) detection biosensor was constructed using an allosteric probe-conjugated PAM site formation in hybridization chain reaction (HCR) integrated with the CRISPR/Cas12a system (APF-CRISPR). In the absence of ATP, an aptamer-containing probe (AP) is in a stem-loop structure, which blocks the initiation of HCR. In the presence of ATP, the structure of AP is changed upon ATP binding, resulting in the release of the HCR trigger strand and the production of long duplex DNA with many PAM sites. Since the presence of a duplex PAM site is crucial for triggering the cleavage activity of CRISPR/Cas12a, the ATP-dependent formation of the PAM site in HCR products can initiate the FQ-reporter cleavage, allowing ATP quantification by measuring the fluorescent signals. By optimizing the sequence elements and detection conditions, the aptasensor demonstrated superior detection performance. The limit of detection (LOD) of the assay was estimated to be 1.16 nM, where the standard deviation of the blank was calculated based on six repeated measurements. The dynamic range of the detection was 25-750 nM, and the whole workflow of the assay was approximately 60min. In addition, the reliability and practicability of the aptasensor were validated by comparing it with a commercially available chemiluminescence kit for ATP detection in serum. Due to its high sensitivity, specificity, and reliable performance, the APF-CRISPR holds great potential in bioanalytical studies for ATP detection. In addition, we have provided a proof-of-principle for constructing a CRISPR/Cas12a-based aptasensor, in which the PAM is utilized to regulate Cas12a cleavage activity.

Examination of in vitro and in vivo antitumor activity of PARP1 selective inhibitor D0112-005.

e15115 Background: The approved PARP inhibitors have demonstrated efficacy in ovarian, breast, prostate, and pancreatic cancers, particularly in homologous recombination repair (HRR)-deficient tumors, including BRCA mutant tumors. The severe hematological toxicity of first-generation PARPi in combination with chemotherapy is due to the lack of selectivity for PARP2. So, we developed selective PARP1 inhibitor D0112-005 with the aim to improve safety and efficacy. Methods: The selectivity of D0112-005 on PARP1, PARP2 was measured by chemiluminescent assay kit and PARP trap™ assay kit. The anti-proliferative ability of D0112-005 was evaluated by CCK-8 in BRCA mutant cell lines. In vivo anti-tumor effect of D0112-005 was evaluated in MDA-MB-436 BRCA1 mutant xenograft model. The potential for hematologic toxicity was evaluated in rats for 28 days repeat-dose and dogs for 14 days repeat-dose. Results: D0112-005 is a highly potent and selective inhibitor of PARP1 with 2000-fold selectivity for PARP1 over PARP2 and PARP3. D0112-005 trapped PARP1-DNA with an EC50 value of 6.49 nM. In contrast, the EC50 of PARP2-DNA trapping was 430μM. These data demonstrate that D0112-005 is a potent and selective PARP1 trapper. D0112-005 showed high anti-proliferation activity against BRCA mutant MDA-MB-436 and HCC1395 cell lines, with IC50 values of 2.06 nM and 2.446 nM, respectively. In the MDA-MB-436 BRCA1m xenograft model, a dose-dependent anti-tumor effect was observed after 21 days administration, with TGIs of 38.77%, 106.7% and 111.73% at the dose of 0.1, 0.3 or 1 mg/kg once daily by oral, respectively. In the 1 mg/kg group, the anti-tumor efficacy was maintained after 14 days of drug withdrawal. D0112-005 showed well tolerance without bodyweight loss. In rat 28 days repeat dose study, D0112-005 100mg/kg had less changes on hematologic parameters compared with Olaparib. The main toxic reaction of D0112-005 (10mg/kg) was reversible thrombocytopenia in dog 14 days repeated toxicity study. Conclusions: D0112-005 potently and selectively inhibits PARP1 resulting in excellent anti-tumor activity in vivo and in vitro, which also good safety profile in the repeated toxicity study in rats and dogs.

Development of a chemiluminescence assay for tissue plasminogen activator inhibitor complex and its applicability to gastric cancer

BackgroundVenous thromboembolism (VTE), is a noteworthy complication in individuals with gastric cancer, but the current diagnosis and treatment methods lack accuracy. In this study, we developed a t-PAIC chemiluminescence kit and employed chemiluminescence to detect the tissue plasminogen activator inhibitor complex (t-PAIC), thrombin-antithrombin III complex (TAT), plasmin-α2-plasmin inhibitor complex (PIC) and thrombomodulin (TM), combined with D-dimer and fibrin degradation products (FDP), to investigate their diagnostic potential for venous thrombosis in gastric cancer patients. The study assessed variations in six indicators among gastric cancer patients at different stages.ResultsThe t-PAIC reagent showed LOD is 1.2 ng/mL and a linear factor R greater than 0.99. The reagents demonstrated accurate results, with all accuracy deviations being within 5%. The intra-batch and inter-batch CVs for the t-PAIC reagent were both within 8%. The correlation coefficient R between this method and Sysmex was 0.979. Gastric cancer patients exhibited elevated levels of TAT, PIC, TM, D-D, FDP compared to the healthy population, while no significant difference was observed in t-PAIC. In the staging of gastric cancer, patients in III-IV stages exhibit higher levels of the six markers compared to those in I-II stages. The ROC curve indicates an enhancement in sensitivity and specificity of the combined diagnosis of four or six indicators.ConclusionOur chemiluminescence assay performs comparably to Sysmex’s method and at a reduced cost. The use of multiple markers, including t-PAIC, TM, TAT, PIC, D-D, and FDP, is superior to the use of single markers for diagnosing VTE in patients with malignant tumors. Gastric cancer patients should be screened for the six markers to facilitate proactive prophylaxis, determine the most appropriate treatment timing, ameliorate their prognosis, decrease the occurrence of venous thrombosis and mortality, and extend their survival.

A method of quantitative chemiluminescence immunoassay for the concentration of Growth differentiation factor-15

Growth differentiation factor-15 (GDF-15), a member of the transforming growth factor (TGF-β) superfamily, and is expressed and secreted in response to inflammation, oxidative stress and hypoxia. It has been shown in several studies to be a predictor of heart failure. However, the only kits available on the market are ELISA kits, which are costly and error-prone and are not conducive for clinical use. Here, we developed a chemiluminescence kit which optimized the reaction conditions and the reaction time was reduced to 10 min. We further proved that it can be used to measure GDF-15 in serum or plasma accurately and fastly, and provide additional information for the diagnosis of heart failure disease. Methodological comparison and clinical study verified this method is a reliable, economical and highly automated blood test method.•All necessary steps and the reagents needed are provided.•Reliability of the chemiluminescence immunoassay was verified by analyzing serum GDF-15 levels from different groups.•GDF-15 can provide clinicians with reliable prediction and disease assessment of heart failure.

Serum iodine concentration and its associations with thyroid function and dietary iodine in pregnant women in the southeast coast of China: a cross-sectional study.

Iodine deficiency is a major public health problem in pregnant women. Serum iodine (SI) may represent a useful biomarker for iodine nutrition evaluation. We aimed to assess the relationship between serum iodine concentration (SIC) and urinary iodine concentration (UIC), dietary iodine, thyroid function, and thyroid diseases in pregnant women in the southeast coast of China, and to provide a normal reference range of SIC for pregnant women. A multistage random sampling method was used to select the study population. We collected urine and blood samples from pregnant women and determined UIC and SIC as well as thyroid function using Arsenic-Cerium Catalytic Spectrophotometry, inductively coupled plasma mass spectrometry, and Beckman Coulter Access2 chemiluminescent immunoanalyzer and kit, respectively, and administered a questionnaire on dietary iodine intake in pregnant women. There was a significant negative correlation between SI and thyroid-stimulating hormone (TSH) (r = -0.141) and a significant positive correlation between SI and free triiodothyronine (FT3) (r = 0.106), free thyroxine (FT4) (r = 0.236), triiodothyronine (TT3) (r = 0.229), total thyroxine (TT4) (r = 0.433), and dietary iodine intake (r = 0.068). There was a significant difference in SI levels of pregnancy between the second (78.13 μg/L) and third trimester (75.37 μg/L) (p = 0.018). SI levels between inadequate intake (74.58 μg/L) and appropriate intake (77.92 μg/L) groups were statistically different (p = 0.036). Low SIC was a risk factor for the development of hypothyroxinemia (adjusted OR = 3.14, 95% confidence interval: 1.75-5.66). The reference range for SIC in normal pregnant women is 45.03-112.44 μg/L. SI may be a composite indicator of iodine nutritional status and thyroid function.

A novel target-triggered signal chemiluminescence kit for thrombin detection based on fusiform Au/MIL-53(Fe)

In this work, a fusiform Au/MIL-53(Fe) catalyst was used to construct a chemiluminescence (CL) kit for the sensitive and rapid detection of thrombin (THR). The porous silica microspheres encapsulated with luminol in holes by thrombin aptamer (THR-APT/Luminol/SPSiO2) and the fusiform Au/MIL-53(Fe) modified with thrombin aptamer complementary chains (Au/MIL-53(Fe)-SSDNA) were prepared. Then, a CL kit for THR detection was constructed by using the prepared composites. When thrombin is added to the reaction system, it binds to its aptamer (THR-APT) to open the holes of SPSiO2, which cause luminol and Au/MIL-53(Fe) release. Released luminol enters the detection system and triggers the reaction of luminol–H2O2–NaOH with the catalyst of Au/MIL-53(Fe), and produces a CL signal. The detection limit and the linear range of the kit were 4.7 × 10−15 M and 1.5 × 10−14 – 3.5 × 10−10 M, respectively. The CL kit also showed high stability, selectivity and reproducibility, and was successfully applied to the determination of THR in serum samples. Therefore, the proposed method for detecting THR has great application potential in the diagnosis of blood-related disease markers.

The Stability of the Anti-Müllerian Hormone in Serum and Plasma Samples under Various Preanalytical Conditions.

The anti-Müllerian hormone (AMH) is a glycoprotein that plays an important role in prenatal sex differentiation. It is used as a biomarker in polycystic ovary syndrome (PCOS) diagnostics, as well as for estimating an individual's ovarian reserve and the ovarian response to hormonal stimulation during in vitro fertilization (IVF). The aim of this study was to test the stability of AMH during various preanalytical conditions that are in accordance with the ISBER (International Society for Biological and Environmental Repositories) protocol. Plasma and serum samples were taken from each of the 26 participants. The samples were then processed according to the ISBER protocol. AMH levels were measured in all the samples simultaneously using the chemiluminescent kit ACCESS AMH in a UniCel® DxI 800 Immunoassay System (Beckman Coulter, Brea, CA, USA). The study proved that AMH retains a relatively high degree of stability during repeated freezing and thawing in serum. AMH was shown to be less stable in plasma samples. Room temperature proved to be the least suitable condition for the storage of samples before performing the biomarker analysis. During the testing of storage stability at 5-7 °C, the values decreased over time for all the plasma samples but remained stable in the serum samples. We proved that AMH is highly stable under various stress conditions. The anti-Müllerian hormone retained the greatest stability in the serum samples.

Oxaliplatin Induces Immunogenic Cell Death in Human and Murine Laryngeal Cancer

Background Cisplatin resistance is observed in patients with laryngeal cancer. The present study was designed to explore the efficacy of oxaliplatin on laryngeal cancer and elucidate the underlying mechanisms. Methods Cell viability was determined by using MTT assays. Cell apoptosis was determined by using annexin V and propidium iodide (PI) staining. Flow cytometry and immunofluorescence were applied to determine the levels of calreticulin (CALR) and DiD (1,1-dioctadecyl-3,3,3,3-tetramethylindodicarbocyanine). Flow cytometry was applied to analyze the levels of CD83, CD86, IFN-γ-producing CD8+ T cells, and CD4+CD25+FoxP3+ Tregs. The levels of adenosine triphosphate (ATP) were determined by using a chemiluminescent ATP kit and cytokines were determined by using specific enzyme-linked immunosorbent assays (ELISAs). The levels of HMGB1 were determined by using Western blot and ELISA, respectively. The xenograft animal model was constructed to evaluate the antitumor effects of oxaliplatin. Results Oxaliplatin inhibited cell growth, promoted cell apoptosis, and induced the levels of CALR, ATP, and high mobility group box protein 1 (HMGB1) in Hep-2 cells. Oxaliplatin-treated Hep-2 cells increased the intensity of DiD and the levels of CD83 and CD86 in dendritic cells (DCs), as well as induced the supernatant IL-6 and TNF-α. Oxaliplatin-treated primary laryngeal cancer cell-pulsed DCs increased the IFN-γ-producing CD8+ T cells and suppressed CD4+CD25+FoxP3+ Tregs. In vivo data showed that oxaliplatin suppressed tumor growth and increased the populations of CD86+CD80+ and CD8+CD45+ cells in the tumor tissues. Conclusion Treatment with oxaliplatin inhibited laryngeal cancer cells by inducing immunogenic cell death.

P241

Abstract Background In recent decades, biological drugs targeting anti-tumour necrosis factor-α (TNF-α) have represented the cornerstone in the treatment of inflammatory bowel diseases. Currently, anti- TNF-α represents a breakthrough in patient care. However, 20–50% of patients experience primary or secondary loss of response. This may be due to pharmacodynamic and/or pharmacokinetic issues, resulting in subtherapeutic drug concentrations, frequently related to the development of anti-drug antibodies (ADA). In this context, therapeutic drug monitoring (TDM) is essential to patients’ management in order to pinpoint the basis of reduced efficacy. Indeed, a fast and reliable assessments of TDM is mandatory to allow rapid intervention, to avoid toxicity and improve treatment efficacy. In this study we assess the analytical performance of a novel fully automated chemiluminescent assay in measuring biological drugs levels and ADA serum concentration and to compare its performances to the current diagnostic method (ELISA). Methods Serum levels of biological drugs (Infliximab and Adalimumab) and their respective ADA were measured in twenty infliximab (IFX)-treated IBD patients and twenty adalimumab (ADL)-treated IBD patients using both the Promonitor® ELISA kits (Grifols) and the i-TRACKER chemiluminescent (CLIA) kits (Theradiag Results The CLIA method is a random-access platform that allows the continuous loading of samples, while the ELISA is a time-consuming manual method to be planned in advance to reduce expenses. Actually, in our laboratory is performed only twice a month. A very good correlation was observed both for Infliximab (Spearman r=0.9695, 95%CI = 0,92-0,99, p<0.0001) and Adalimumab serum levels (Spearman r=0.9476, 95%CI = 0,86-0,98, p<0.0001). Among the patients with undetectable IFX serum levels, 6/8 (75%) resulted ADA positive by ELISA versus 8/8 (100%) by CLIA. Moreover, CLIA disclosed very high ADA concentration in 3 samples compared to borderline results by ELISA. Regarding ADL, all the 9 patients with undetectable serum levels presented similar ADA concentration as tested with ELISA or CLIA. Conclusion In conclusion, the i-TRACKER CLIA Infliximab and Adalimumab assays showed a very good correlation for serum-based drugs level quantification as compared to the related ELISA methods. Furthermore, a good agreement was observed for ADA analysis, with a higher sensitivity against anti-IFX antibodies by CLIA compared to ELISA. Our data clearly highlighted that a fully automated assay for TDM would certainly reduce costs and significantly improve the management of IBD patients in terms of a shorter turn-around time.

Self-Blockade of PD-L1 with Bacteria-Derived Outer-Membrane Vesicle for Enhanced Cancer Immunotherapy.

The checkpoint inhibitor therapy that blocks programmed death-1 (PD-1) and its major ligand PD-L1 has achieved encouraging clinical efficacy in certain cancers. However, the binding of checkpoint inhibitors with other immune cells that express PD-L1 often results in a low response rate to the blockade and severe adverse effects. Herein, an LyP1 polypeptide-modified outer-membrane vesicle (LOMV) loaded with a PD-1 plasmid is developed to achieve self-blockade of PD-L1 in tumor cells. The nanocarriers accumulate in the tumor tissue through OMV-targeting ability and are internalized into the tumor cells via the LyP1-mediated target, subsequently delivering PD-1 plasmid into the nucleus, leading to the expression of PD-1 by the tumor cells. In addition, a magnetic particle chemiluminescence kit is developed to quantitatively detect the binding rate of PD-1/PD-L1. The self-expressed PD-1 bonded with the PD-L1 is expressed by both autologous and neighboring tumor cells, achieving self-blockade. Simultaneously, the outer-membrane protein of LOMV recruits cytotoxic lymphocyte cells and natural killer cells to tumor tissues and stimulates them to secrete IFN-γ , improving the antitumor activity of the PD-1/PD-L1 self-blocking therapy.

One-pot label-free dual-aptasensor as a chemiluminescent tool kit simultaneously detect adenosine triphosphate and chloramphenicol in foods

The chemiluminescence (CL) analysis based on label-free dual-aptasensor was developed for simultaneous detection of adenosine triphosphate (ATP) and chloramphenicol (CAP) in food. Magnetic microspheres and polystyrene microspheres used as separating and immobilizing carriers which immobilized the two different captured DNA, respectively. Then these carriers were put in the mixture of ATPs, CAPs, ATP-binding aptamers and CAP-binding aptamers to make one-pot label-free recognized interaction. The more ATP or CAP molecules binding their aptamers, the less aptamers left on the surface of carriers reducing the CL signals. The proposed aptasensor exhibited high selectivity and sensitivity for ATP and CAP with the limits of detection of 3.76 × 10−8 moL/L and 2.48 × 10−8 moL/L, respectively. Finally, this method is further validated by measuring the recovery of ATP/CAP spiked in three different food samples.

TNF-Like Weak Inducer of Apoptosis Promotes Angiogenesis, Thereby Exacerbating Cutaneous Psoriatic Disease

TNF-Like Weak Inducer of Apoptosis Promotes Angiogenesis, Thereby Exacerbating Cutaneous Psoriatic Disease

Hydrazide mediated oriented coupling of antibodies on quantum dot beads for enhancing detection performance of immunochromatographic assay

Immunochromatographic assays (ICAs) are one of the most popular on-site diagnostic tools. The bio-activity of the probe holds great promise for the detection performance of ICA. The orientation of antibodies on nanoparticle surface plays a vital role in improving the bio-activity of the probe. Hydrazide mediated oriented coupling (HDZ-O) strategy can erect the antibodies on the particle surface via the nucleophilic addition reaction between the hydrazide group of particles and the aldehyde group of the Fc region of antibodies. In this work, we synthesized the hydrazide and carboxylic group modified quantum dot beads (QBs-NH-NH2, and QBs-COOH) and compared two coupling strategies for preparing QB probes systematically. Results showed the reaction time for producing QB probe by using HDZ-O method was 20 min, and the optimal labeled antibody content was 80 μg per mg of QBs. Those for carbodiimide method were 180 min and 320 μg per mg of QBs. Moreover, the QB probe by HDZ-O showed a higher bio-activity than that by carbodiimide method under their optimal labeled antibody concentrations. Subsequently, the QB probe by HDZ-O strategy was applied further in sandwich ICA for hepatitis B surface antigen (HBsAg) detection. The results indicated that the strip has a widely dynamic linearity with HBsAg concentration ranging from 0.05 ng/mL to 3200 ng/mL. The limit of detection of the strip is 0.05 ng/mL, which is approximately fourfold lower than that of the probe prepared by carbodiimide method. In addition, the ICA strip also showed acceptable accuracy and precision for HBsAg quantitative detection in real serum samples, which have average recoveries in intra- and inter-assays that vary from 89.16% to 97.63% with the variable coefficients less than 6.98%. The proposed ICA strip showed good agreement (R2 > 0.94) with a commercial chemiluminescence kit for 40 of clinical serum samples. All in all, this study proposed a robust strategy to immobilize the antibodies with proper orientation on the surface of QBs, and the resultant QB probe can improve the detection performance of sandwich LFIA platform remarkably.

Pd(II) and Rh(III) Complexes with Isoquinoline Derivatives Induced Mitochondria-Mediated Apoptotic and Autophagic Cell Death in HepG2 Cells

Nonplatinum metal complexes of [Pd(L1)Cl2] (C1), [Rh(L1)Cl3(DMSO)] (C2), [Pd(L2)Cl2] (C3), and [Rh(L3)Cl3(DMSO)] (C4) with isoquinoline derivatives have been prepared and characterized. C1–C4 exhib...

Performance evaluation and clinical application of three antibody test kits for novel coronavirus (SARS-CoV-2)

Objective To evaluate the performance of three antibody kits for novel coronavirus (SARS-CoV-2) and to investigate the feasibility and advantages of them in clinical application. Methods A total of 104 patients who were admitted to Guangzhou Eighth People's Hospital with COVID-19 from January to February 2020 were selected as research group. Fifty-one healthy subjects were selected during the same period as negative control group. Serum antibodies (IgM/IgG) against SARS-CoV-2 were detected using two kinds of colloidal gold kits (A and B kits) and one chemiluminescence kit (C kit). The positive rates of SARS-CoV-2 nucleic acid in different samples from patients with COVID-19 were retrospectively analyzed. Results The clinical sensitivity of A kit to detect SARS-CoV-2-specific IgM and IgG was 77.88% (81/104) and 65.38% (68/104), respectively, and the clinical specificity was 70.59% (36/51) and 100.00% (51/51). However, the false positive rate in IgM detection was as high as 29.41% (15/51). The sensitivity of B kit to test total antibodies to SARS-CoV-2 was 63.46% (66/104), and the clinical specificity was 94.12% (48/51). The clinical sensitivity of C kit to detect SARS-CoV-2-specific IgM and IgG were respectively 31.73% (33/104) and 64.42% (67/104), and the clinical specificity were both 98.04% (50/51). There was a moderate correlation between the detection results of two colloidal gold kits and the chemiluminescence kit with the Kappa values of 0.462 and 0.587 (Z=6.157, P<0.01; Z=7.345, P<0.01). C kit had the highest positive detection rate for IgG, and would be more reliable to be used for IgG detection in COVID-19 patients 14 d after onset. The total positive detection rate of nucleic acid in all types of samples was 63.46% (66/104). The highest positive detection rate was in throat swabs or sputum samples, followed by those in blood samples and anal swabs. No viral nucleic acid was detected in urine samples for the time being. Conclusions SARS-CoV-2-specific antibodies could be detected in the early or late stage of COVID-19. The method of antibody detection has the advantages of shorter detection time, simple operation and high biological safety, indicating that it could be used as a supplementary or auxiliary detection for the diagnosis of suspected COVID-19 cases with negative nucleic acid test results. The chemiluminescence kit has good sensitivity and specificity, and is well recommended for clinical laboratories. Key words: SARS-CoV-2; Chemiluminescence immunoassay; Colloidal gold immunoaasay; Nucleic acid detection; Performance evaluation; Clinical application

Chidamide Combined with Decitabine Synergistically Induce Apoptosis of Acute Myeloid Leukemia By up-Regulating Perp gene In Vivo and in Vitro

Background: Acute myeloid leukemia (AML) is a malignant clonal disease of hematopoietic stem cells. The long term survival of AML is not satisfactory, so new treatment should be explored. Here, we show that chidamide(CH), a histone deacetylase inhibitor, combined with decitabine(DE) induces apoptosis of AML cell lines and primary refractory/relapsed AML cells by up-regulating PERP. This may provide a new option for AML treatment. Methods and results: We first examined the half-inhibitory concentrations (IC50) of chidamide and decitabine against THP-1, MV4-11, HL60 and Kasumi-1 cell lines using MTT (Fig1 A-D). And the drug combination is performed according to the IC50. In the double-drug combination experiment, we used MTT to detect the effect of drugs on the proliferation of the four cell lines (Fig1 E-H), used calcusyn 2.0 software to calculate the synergistic effect (Fig2), flow cytometry to detect apoptosis (Fig3 A-D), and western blot to detect the pro-apoptotic protein (C-CASPASE 3 and C-CASPASE 9) and anti-apoptotic proteins (CASPASE 8, BCL-2 and BCL-XL) (Fig3 E-H). We found that chidamide combined with decitabine synergistically inhibited proliferation of AML cell lines, induced apoptosis, up-regulated pro-apoptotic protein levels and down-regulated anti-apoptotic protein levels. To investigate this combination therapeutic effect in vivo, we selected 5 refractory/relapsed AML patients, extracted primary AML cells, and used ATP chemiluminescence kit for drug sensitivity test. The results confirmed that four of the five patients with AML showed sensitivity to combinations (Fig4). To further explore the mechanism of action of CH combination with DE, we performed transcriptome sequencing (Fig5). Analysis of the sequencing results, the gene PERP, which shows the significant difference in the apoptotic pathway, was further examined. The PERP is a new member of the PMP-22/GAS3 family as an apoptosis-associated target of TP53. RT-QPCR and WB verified the role of PERP in apoptosis in DE and CH combination (Fig6). The results showed that the combination could up-regulate the PERP gene than the single drug. When we explored the role of the PERP gene in AML cell lines, we knocked down the PERP gene by lentivirus and detected cell proliferation after infection. Pretreated AML cell lines by lentivirus-infection (Fig7A-F), then we tested for proliferation (Fig7G-I) (Fig8A-C), apoptosis (Fig8D-E), and pro-apoptotic protein expression (Fig8G-I). The results showed that knocking down the PERP gene promoted the proliferation of AML cell lines and attenuated the sensitivity of AML cell lines to chemotherapeutic drugs. We also compare the mRNA level of PERP between 35 AML patients and 20 normal and found that the PERP mRNA of AML patients was significantly lower than the normal (Fig9). MV4-11 cells were exposed to CH and DE alone or in combination, and proteomic sequencing was performed to examine the effect of the drug on cellular protein. The result indicates to some extent that CH contributes more to the combined effect. And the drug causes changes in multiple pathways in the cell (Fig10). Conclusion: Our experiments revealed that CH combined with DE may have therapeutic effects on AML and, to some extent, reveal the mechanism of dual drug combination. Legends to figures Fig1. 50% inhibitory concentration (IC50) values of chidamide and decitabine alone treated AML cell lines. Fig2. Chidamide acts synergistically in AML with DE. Fig3. Chidamide in combination with decitabine significantly induced apoptosis in AML cell lines. Fig4. The sensitivity of relapsed or refractory AML primary cells to chidamide and decitabine alone or in combination. Fig5. Gene expression analysis showed an obvious difference based on treatment. Fig6. Verify transcriptome sequencing results by real-time QPCR and by western blotting with or without drug treatment. Fig7. The effect of down-regulation of PERP by Lentivirus-mediated RNAi on AML cells proliferation. Fig8. PERP knockdown causes AML cells to develop resistance to combination drugs. Fig9.The level of PERP mRNA in peripheral blood mononuclear cells of AML and normal humans. Fig10. Proteomics sequencing results show the differentially expressed protein and a cluster analysis of the functions or pathways enriched by differentially expressed proteins in GO and KEGG pathways compared to single agents. Disclosures No relevant conflicts of interest to declare.

Contribution of the cold shock protein CspA to virulence in Xanthomonas oryzae pv. oryzae.

Summary Xanthomonas oryzae pv. oryzae (Xoo) causes a damaging bacterial leaf blight disease in rice. Cold shock proteins (Csps) are highly conserved nucleic acid‐binding proteins present in various bacterial genera, but relatively little is known about their functions in Xanthomonas. Herein, we identified four Csps (CspA–CspD) in the Xoo PXO99A strain. Deletion of cspA decreased cold adaptation and a few known pathogenic factors, including bacterial pathogenicity, biofilm formation and polysaccharide production. Furthermore, we performed transcriptomic and chromosome immunoprecipitation (ChIP) experiments to identify direct targets of CspA and to determine its DNA‐binding sequence. Integrative data analysis revealed that CspA directly regulates two genes, PXO_RS11830 and PXO_RS01060, by binding to a conserved CCAAT sequence in the promoter region. We generated single‐deletion mutants of each gene and the results indicate that both are responsible for Xanthomonas pathogenicity. In addition, quantitative real‐time polymerase chain reaction and western blotting showed that CspA suppressed the expression of its direct targets. In summary, our study clarifies the characteristics of Csps in Xanthomonas and greatly advances our understanding of the mechanisms underlying the contribution of CspA to bacterial virulence.

Stability of total prostate-specific antigen and free prostate-specific antigen after 10 years' storage.

PSA is a serine protease composed of 240 amino acids in a single polypeptide chain and is a routine parameter in prostate cancer diagnostics. The aim of our study was to test the long-term stability of tPSA and fPSA after 10 years' storage at -80°C. We analyzed two aliquots from 55 serum samples. The first was assayed in routine testing at the time of establishing the diagnosis. The second was thawed for further testing after approximately 10 years' storage at -80°C. The mean of storage time was 10.41 years (min-max: 9.35-11.40 years). We compared the results of tPSA and fPSA. We calculated the fPSA/tPSA ratio and compared the results of clinical evaluation. Serum tPSA and fPSA levels were assayed using chemiluminescent kits Access Hybritech PSA and free PSA. All measurements were performed using the instrument UniCel® DxI 800. tPSA decreased 3.59% on average with a correlation r=0.9213, and fPSA increased at an average of 2.41% with a correlation r=0.9338. The fPSA/tPSA ratio increased 0.80% on average with a correlation r=0.9174. On clinical evaluation, five samples had fallen to a less malignant category and three samples had risen to a higher malignant category compared with the original results. The stability of tPSA and fPSA levels in serum is sufficient after 10 years' storage at -80°C. Calculation of the fPSA/tPSA ratio is not recommended due to the change in the category of malignancy of 15% of the samples.

PARP3 inhibitors ME0328 and olaparib potentiate vinorelbine sensitization in breast cancer cell lines.

PARP-3 is member of the PARP family of poly (ADP-ribose) polymerases involved in ADPribosylation. PARPs are involved in the basic mechanisms of DNA repair. PARP3, a critical player for efficient mitotic progression, is required for the stabilization of the mitotic spindle by regulation of the mitotic components, NuMA and Tankyrase 1. The sensitization effect of vinorelbine on PARP3 inhibition-induced cytotoxicity was assessed by the SRB assay. The contribution of programed cell death and cell cycle arrest to the sensitization effect were determined by assessing changes in Annexin V, a marker of apoptosis. Alterations in cell cycle progression were assessed by cell cycle analysis. We used immunofluorescence to assess the effect of vinorelbine and/or PARP3 inhibitors on tubulin and microtubule depolarization. The PARP3 chemiluminescent assay kit was used for PARP3 activity. PARP3 inhibitors sensitize breast cancer cells to vinorelbine, a vinca alkaloid used in the treatment of metastatic breast cancer. Olaparib which was originally described as a PARP1 and 2 inhibitor has recently been shown to be a potent PARP3 inhibitor while ME0328 is a more selective PARP3 inhibitor. The combination of vinorelbine with nontoxic concentrations of ME0328 or olaparib reduces vinorelbine resistance by 10 and 17 fold, respectively, potentiating vinorelbine-induced arrest at the G2/M boundary. In addition, PARP3 inhibition potentiates vinorelbine interaction with tubulin. Furthermore, olaparib or ME0328 potentiates vinorelbine-induced PARP3 inhibition, mitotic arrest, and apoptosis. Our results indicated this approach with PARP3 inhibitors and vinorelbine is unique and promising for breast cancer patients with metastases. This combination could significantly increase the survival of breast cancer patients with metastases.

Dual-labeled chemiluminescence enzyme immunoassay for simultaneous measurement of total prostate specific antigen (TPSA) and free prostate specific antigen (FPSA).

The specificity for early diagnostic of prostate-specific antigen (PSA) is low because the current technology mostly allows the detection of only one biomarker at one time. In this work, a dual-labeled chemiluminescence enzyme immunoassay (CLEIA) for simultaneous measurement of total PSA (TPSA) and free PSA (FPSA) was proposed. Anti-PSA McAb (Mab1) was immobilized on a microplate as the solid phase, horseradish peroxidase (HRP)-labeled anti-TPSA monoclonal antibody (McAb2) and alkaline phosphatase (ALP)-labeled anti-FPSA McAb3 were used as detection antibodies. Two chemiluminescence reactions of HRP with luminol and ALP with 4-methoxy-4-(3-phosphate-phenyl)-spiro-(1,2-dioxetane-3,2'-adamantane) (AMPPD) were used as the signal detecting system. Based on a sandwich model, the amount of FPSA and TPSA could be determined simultaneously. The effects of several physico-chemical parameters were studied and optimized. Cross-reactivities of six common tumor markers in serum were studied. The proposed method presented the sensitivity of 0.03ng ml-1 and 0.05ng ml-1 for FPSA and TPSA respectively, with low cross-reactivities. Compared with the results from commercial chemiluminescent kits there was good correlation, indicating that this established method could be used to simultaneously to measure the concentrations of FPSA and TPSA in one serum sample and also could greatly facilitate the early diagnosis for PCa in clinical practice.