Targeting B4GALT7 suppresses the proliferation, migration and invasion of hepatocellular carcinoma through the Cdc2/CyclinB1 and miR-338-3p/MMP2 pathway.

Background: As a three-dimensional network involving glycosaminoglycans (GAGs), proteoglycans (PGs) and other glycoproteins, the role of extracellular matrix (ECM) in tumorigenesis is well revealed. Abnormal glycosylation in liver cancer is correlated with tumorigenesis and chemoresistance. However, the role of galactosyltransferase in HCC (hepatocellular carcinoma) is largely unknown. Methods: Here, the oncogenic functions of B4GALT7 (beta-1,4-galactosyltransferase 7) were identified in HCC by a panel of in vitro experiments, including MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), colony formation, transwell and flow cytometry assay. The expression of B4GALT7 in HCC cell lines and tissues were examined by qPCR (real-time quantitative polymerase chain reaction) and western blot assay. The binding between B4GALT7 and miR-338-3p was examined by dual-luciferase reporter assay. Results: B4GALT7 encodes galactosyltransferase I and it is highly expressed in HCC cells and human HCC tissues compared with para-tumor specimens. MiR-338-3p was identified to bind the 3' UTR (untranslated region) of B4GALT7. Highly expressed miR-338-3p suppressed HCC cell invasive abilities and rescued the tumor-promoting effect of B4GALT7 in HCC. ShRNA (short hairpin RNA) mediated B4GALT7 suppression reduced HCC cell invasive abilities, and inhibited the expression of MMP-2 and Erk signaling. Conclusion: These findings identified B4GALT7 as a potential prognostic biomarker and therapeutic target for HCC.

A Semisynthetic Bioluminescence Sensor for Ratiometric Imaging of Metal Ions In Vivo Using DNAzymes Conjugated to An Engineered Nano-Luciferase.

DNA-based probes have gained significant attention as versatile tools for biochemical analysis, benefiting from their programmability and biocompatibility. However, most existing DNA-based probes rely on fluorescence as the signal output, which can be problematic due to issues like autofluorescence and scattering when applied in complex biological materials such as living cells or tissues. Herein, we report the development of bioluminescent nucleic acid (bioLUNA) sensors that offer laser excitation-independent and ratiometric imaging of the target in vivo. The system is based on computational modelling and mutagenesis investigations of a genetic fusion between circular permutated Nano-luciferase (NLuc) and HaloTag, enabling the conjugation of the protein with a DNAzyme. In the presence of Zn2+ , the DNAzyme sensor releases the fluorophore-labelled strand, leading to a reduction in bioluminescent resonance energy transfer (BRET) between the luciferase and fluorophore. Consequently, this process induces ratiometric changes in the bioluminescent signal. We demonstrated that this bioLUNA sensor enabled imaging of both exogenous Zn2+ in vivo and endogenous Zn2+ efflux in normal epithelial prostate and prostate tumors. This work expands the DNAzyme sensors to using bioluminescence and thus has enriched the toolbox of nucleic acid sensors for a broad range of biomedical applications.

Dasatinib in combination with BMS-754807 induce synergistic cytotoxicity in lung cancer cells through inhibiting lung cancer cell growth, and inducing autophagy as well as cell cycle arrest at the G1 phase.

Lung cancer is the leading cause of cancer-related deaths worldwide. Combination of drugs targeting independent signaling pathways would effectively block the proliferation of cancer cells with lower concentrations and stronger synergy effects. Dasatinib, a multi-targeted protein tyrosine kinase inhibitor targeting BCR-ABL and kinases of SRC family, has been successfully applied in the treatment of chronic myeloid leukemia (CML). BMS-754807, an inhibitor targeting the insulin-like growth factor 1 receptor (IGF-IR) and insulin receptor (IR) family kinases, has been in phase I development for the treatment of a variety of human cancers. Herein, we demonstrated that dasatinib in combination with BMS-754807 inhibited lung cancer cell growth, while induced autophagy as well as cell cycle arrest at the G1 phase. Dasatinib in combination with BMS-754807 suppressed the expression of cell cycle marker proteins, Rb, p-Rb, CDK4, CDK6 and Cyclin D1, and the PI3K/Akt/mTOR signaling pathway. Dasatinib in combination with BMS-754807 induced autophagy in lung cancer cells, evidenced by the upregulation of LC3B II and beclin-1, the downregulation of LC3B I and SQSTM1/p62, and the autophagic flux observed with a confocal fluorescence microscopy. Furthermore, dasatinib (18 mg/kg) in combination with BMS-754807 (18 mg/kg) inhibited the growth of tumors in NCI-H3255 xenografts without changing the bodyweight. Overall, our results suggest that dasatinib in combination with BMS-754807 inhibits the lung cancer cell proliferation in vitro and tumor growth in vitro, which indicates promising evidence for the application of the drug combination in lung cancer therapy.

A sensitive fluorescence biosensor based on metal ion-mediated DNAzyme activity for amplified detection of acetylcholinesterase.

In this paper, we developed an amplified fluorescence biosensor for acetylcholinesterase (AChE) activity detection by taking advantage of the mercury ion-mediated Mgzyme (Mg2+-dependent DNAzyme) activity. The catalytic activity of Mgzyme can be inhibited by the formation of T-Hg2+-T base pairs between the Mgzyme and mercury ions. Therefore, the Mgzyme-Hg2+ complex has no activity on a molecular beacon (MB) substrate, which afforded a very weak fluorescence background for this biosensor. After the addition of acetylcholinesterase (AChE), the substrate acetylthiocholine could be hydrolyzed to thiocholine, which has a stronger binding power with mercury ions than T-Hg2+-T base pairs. Therefore, the Mgzyme activity was recovered. The activated Mgzyme could hybridize with the MB substrate and undergo many cleavage cycles, resulting in a significant increase of fluorescence intensity. This biosensor displayed high sensitivity with the detection limit as low as 0.01 mU mL-1. Moreover, this design did not require complex composition and sequence design; thus it is simple and convenient. This biosensor was also applied for the determination of AChE in human blood and showed satisfactory results.

Activatable NIR-II Fluorescent Probes Applied in Biomedicine: Progress and Perspectives.

With the advantage of inherent responsiveness that can change the spectroscopic signals from "off" to "on" state in responding to targets (e. g. biological analytes/microenvironmental factors), activatable fluorescent probes have attracted extensive attention and made significant progress in the field of bioimaging and biosensing. Due to the high depth of tissue penetration, minimal tissue damage and negligible background signal at longer wavelengths, the development of second near-infrared window (NIR-II) fluorescent materials provides a new opportunity to develop activable fluorescent probes. Here, we summarized properties, advantages and disadvantages of mainly NIR-II fluorophores (such as rare earth-doped nanoparticles, quantum dots, single-walled carbon nanotubes, small molecule dyes, conjugated polymers and gold nanoclusters), then overviewed current role and development of activatable NIR-II fluorescent probes (AFPs) for biomedical applications including biosensing, bioimaging and therapeutic. The potential challenges and perspectives of AFPs in deep-tissue imaging and clinical application are also discussed.

ß-Cyclodextrin-cholic acid-hyaluronic acid polymer coated Fe3O4-graphene oxide nanohybrids as local chemo-photothermal synergistic agents for enhanced liver tumor therapy.

Synergistic photochemical therapy with high performance and weak side effects is of great importance in hepatocellular carcinoma (HCC) treatment, therefore ingenious construct of nano-based therapy agents with accurate drug delivery and high photothermal conversion efficiency is of critical to the cancer therapy. Herein, an organic-inorganic hybrid nanomaterial (MGO@CD-CA-HA) has been constructed successfully by coating the ß-cyclodextrin-cholic acid-hyaluronic acid polymer (CD-CA-HA) onto the Fe3O4-graphene oxide (MGO). The MGO@CD-CA-HA revealed satisfactory multiple-targeted features including the cholic acid supplied hepatic-target, CD44-receptor target of hyaluronic acid and magnetic target of Fe3O4. Meanwhile, the hydrophobic antitumor drug camptothecin (CPT) was easily loaded by MGO@CD-CA-HA to form the MGO@CD-CA-HA/CPT nanocomposite, and the maximum theoretical adsorption capacity can reach 847.4 mg/g. Based on the facile photothermal response of MGO, the near-infrared radiation (808 nm) induced local hyperthermia was directly generated the apoptosis of tumor cells while triggered the release of CPT. Comparing with other kinds of cancer cells and normal hepatocyte cells, this PCT system provides a significant inhibitory effect for the liver cancer cells in vitro. Furthermore, the synergistic photochemical therapy presented the strong antitumor effect (the tumor inhibition rate > 90 %) in vivo. Thus, this study provided a promising multiple-targeted nanocarrier for chemo-photothermal combination therapy of liver cancer.

Aptamer-based fluorescent sensors for the detection of cancer biomarkers.

Aptamers are short single-stranded RNA or DNA molecules that can recognize a series of targets with high affinity and specificity. Known as "chemical antibodies", aptamers have many unique merits, including ease of chemical synthesis, high chemical stability, low molecular weight, lack of immunogenicity, and ease of modification and manipulation compared to their protein counterparts. Using aptamers as the recognition groups, fluorescent aptasensors provide exciting opportunities for sensitive detection and quantification of analytes. Herein, we give an overview on the recent development of aptamer-based fluorescent sensors for the detection of cancer biomarkers. Based on various nanostructured sensor designs, we extended our discussions on sensitivity, specificity and the potential applications of aptamer-based fluorescent sensors in early diagnosis, treatment and prognosis of cancers.

Silver-ion-mediated Mg2+-dependent DNAzyme activity for amplified fluorescence detection of cysteine.

In this paper, by taking advantage of the fact that silver ions could mediate the Mg2+-dependent DNAzyme (Mgzyme) activity, we for the first time developed a turn-on fluorescent biosensor for amplified cysteine (Cys) detection. Because Mgzyme can interact with the silver ion and form cytosine-Ag+-cytosine (C-Ag+-C) base pairs, the conformation of its catalytic core was changed. As a result, the catalytic activity of Mgzyme was suppressed and the Mgzyme-Ag+ complex could not initiate the cleavage reaction. Therefore, the background fluorescence of the biosensor was very low. In the presence of Cys, Cys can bind tightly to the silver ion and disrupt the C-Ag+-C base pairs in the Mgzyme-Ag+ complex, leading to the restoration of Mgzyme activity. The activated Mgzyme could hybridize with the MB substrate and undergo many cleavage cycles, resulting in a significant increase of fluorescence intensity. This designed strategy provided amplified fluorescence detection of cysteine, with a detection limit of 2 nM. Moreover, the strong binding between Cys and Ag+ ensured that the biosensor had a desirable selectivity for Cys. This sensing system was also used to detect Cys in human urine samples and displayed satisfying results.

Cationic-perylene-G-quadruplex complex based fluorescent biosensor for label-free detection of Pb(2+).

In this work we use a water-soluble cationic perylene derivative (compound 1) as the G-quadruplex (G4) structure fluorescence indicator to construct a fluorescent biosensor for simple, rapid and label-free detection of Pb(2+). In the absence of Pb(2+), strong electrostatic interactions between compound 1 and the G-rich DNA probe (PW17) induced the aggregation of compound 1 and resulted in the fluorescence quenching. In the presence of Pb(2+), the PW17 formed Pb(2+)-stabilized G4 structure, which reduced the aggregation of compound 1 and gave rise to high fluorescence. This allowed us to use convenient "mix-and-detect" protocol for quantitative analysis of Pb(2+). Since Pb(2+) can specially induce PW17 to form compact DNA fold, our proposed biosensor displayed high selectivity for Pb(2+). It also exhibited a high sensitivity to Pb(2+), with a limit of detection of 5.0nM observed. Furthermore, the biosensor was applied for the detection of Pb(2+) in urine and paint samples, and both showed satisfactory results.

Ag nanocluster-based label-free catalytic and molecular beacons for amplified biosensing.

By employing DNAzyme as a recognition group and amplifier, and DNA-stabilized silver nanoclusters (DNA/AgNCs) as signal reporters, we reported for the first time a label-free catalytic and molecular beacon as an amplified biosensing platform for highly selective detection of cofactors such as Pb(2+) and L-histidine.

Multiple functional nanoprobe for contrast-enhanced bimodal cellular imaging and targeted therapy.

Many one-photon fluorescence-based theranostic nanosystems have been developed for simultaneous therapeutic intervention/monitoring for various types of cancers. However, for early diagnosis of cancer, two-photon fluorescence microscopy (TPFM) can realize deep-tissue imaging with higher spatial resolution. In this study, we first report a multiple functional nanoprobe for contrast-enhanced bimodal cellular imaging and targeted therapy. Components of the nanoprobe include (1) two-photon dye-doped mesoporous silica nanoparticles (TPD-MSNs); (2) MnO2 nanosheets that act as a (i) gatekeeper for TPD-MSNs, (ii) quencher for TP fluorescence, and (iii) contrast agent for MRI; (3) cancer cell-targeting aptamers. Guided by aptamers, TPD-MSNs are rapidly internalized into the target cells. Next, intracellular glutathione reduces MnO2 to Mn(2+) ions, resulting in contrast-enhanced TP fluorescence and magnetic resonance signal for cellular imaging. Meanwhile, preloaded doxorubicin and Chlorin e6 are released for chemotherapy and photodynamic therapy, respectively, with a synergistic effect and significantly enhanced therapeutic efficacy.

PEG-mediated osmotic stress induces premature differentiation of the root apical meristem and outgrowth of lateral roots in wheat.

Water stress is one of the major environmental stresses causing growth retardation and yield loss of plants. In the past decades, osmotic adjustment, antioxidant protection, and stomatal movement have been extensively studied, but much less attention has been paid to the study of root system reprogramming to maximize water absorption and survival under water stress. Here, it is shown that polyethylene glycol (PEG)-simulated mild and moderate osmotic stress induced premature differentiation of the root apical meristem (RAM). It is demonstrated that RAM premature differentiation is a conserved adaptive mechanism that is widely adopted by various plants to cope with osmotic stress simulated by PEG 8000, and the occurrence of RAM premature differentiation is directly related to stress tolerance of plants. It is shown that the osmotic stress-induced premature differentiation caused growth cessation of primary roots allowing outgrowth of lateral roots. This work has uncovered a key mechanism for controlling the plastic development of the root system by which plants are capable of survival, growth, or reproduction under water stress.

A superquenched DNAzyme-perylene complex: a convenient, universal and low-background strategy for fluorescence catalytic biosensors.

Taking advantage of the super-quenching effect of the cationic perylene derivative on adjacent fluorophores, we for the first time reported a DNAzyme-perylene complex-based strategy for constructing fluorescence catalytic biosensors with improved sensitivity.

Versatile DNAzyme-based amplified biosensing platforms for nucleic acid, protein, and enzyme activity detection.

DNAzymes have been widely applied as signal amplifiers for enzyme-free and highly sensitive detection of DNA. A few of them have also been employed for amplified detection of other biomolecules via a target-triggered assembly of split or mutated DNAzyme strategy. However, most of these designs adopt Mg(2+)-dependent DNAzyme as the catalytic unit, which suffered from low catalytic cleavage activity. Meanwhile, some DNAzymes with high catalytic activity are not suitable for these designs because the slight modification of the catalytic core might results in remarkably decreased or even no catalytic activity of these DNAzymes. On the basis of DNAzyme topological effect or the terminal protection of small-molecule-linked DNA, we developed two versatile sensing platforms for amplified detection of different biotargets. Since no modification is necessary for the catalytic core of the DNAzyme in these designs, they can employ any DNAzyme with high catalytic activity as amplified unit, which affords a high amplified efficiency for the sensing platform. A catalytic and molecular beacon design was further employed to realize the true enzymatic multiple turnover of DNAzyme. These designs together allow a high sensitivity for the biotargets, resulting in a detection limit of 20 pM, 0.2 U/mL, and 1 ng/mL for target DNA, DNA adenine methylation methyltransferase (Dam MTase), and streptavidin, respectively, much lower than previously reported biosensors. In addition, the proposed sensing strategy is versatile. By conjugating with various recognition units, it can be employed to detect a wide range of biotargets, varying from nucleic acids to proteins with high sensitivity.

Magnetic graphitic nanocapsules for programmed DNA fishing and detection.

Graphene nanomaterials are typically used in biosensing applications, and they have been demonstrated as good fluorescence quenchers. While many conventional amplification platforms are available, developing new nanomaterials and establishing simple, enzyme-free and low-cost strategies for high sensitivity biosensing is still challenging. Therefore, in this work, a core-shell magnetic graphitic nanocapsule (MGN) material is synthesized and its capabilities for the detection of biomolecules are investigated. MGN combines the unique properties of graphene and magnetic particles into one simple and sensitive biosensing platform, which quenches around 98% of the dye fluorescence within minutes. Based on a programmed multipurpose DNA capturing and releasing strategy, the MGN sensing platform demonstrates an outstanding capacity to fish, enrich, and detect DNA. Target DNA molecules as low as 50 pM could be detected, which is 3-fold lower than the limit of detection commonly achieved by carbon nanotube and graphene-based fluorescent biosensors. Moreover, the MGN platform exhibits good sensing specificity against DNA mismatch tests. Overall, therefore, these magnetic graphitic nanocapsules demonstrate a promising tool for molecular disease diagnosis and biomedicine. This simple fishing and enrichment strategy may also be extended to other biological and environmental applications and systems.

Graphene oxide-based biosensor for sensitive fluorescence detection of DNA based on exonuclease III-aided signal amplification.

Based on the super fluorescence quenching efficiency of graphene oxide and exonuclease III aided signal amplification, we develop a facile, sensitive, rapid and cost-effective method for DNA detection. In the presence of target DNA, the target-probe hybridization forms a double-stranded structure and exonuclease III catalyzes the stepwise removal of mononucleotides from the blunt 3' termini of probe, resulting in the recycling of the target DNA and signal amplification. Therefore, our proposed sensor exhibits a high sensitivity towards target DNA with a detection limit of 20 pM, which was even lower than previously reported GO-based DNA sensors without enzymatic amplification, and provides a universal sensing platform for sensitive detection of DNA.

Graphene-DNAzyme based biosensor for amplified fluorescence "turn-on" detection of Pb2+ with a high selectivity.

On the basis of the remarkable difference in affinity of graphene (GO) with ssDNA containing a different number of bases in length, we for the first time report a GO-DNAzyme based biosensor for amplified fluorescence "turn-on" detection of Pb(2+). A FAM-labeled DNAzyme-substrate hybrid acted as both a molecular recognition module and signal reporter and GO as a superquencher. By taking advantage of the super fluorescence quenching efficiency of GO, our proposed biosensor exhibits a high sensitivity toward the target with a detection limit of 300 pM for Pb(2+), which is lower than previously reported for catalytic beacons. Moreover, with the choice of a classic Pb(2+)-dependent GR-5 DNAzyme instead of 8-17 DNAzyme as the catalytic unit, the newly designed sensing system also shows an obviously improved selectivity than previously reported methods. Moreover, the sensing system was used for the determination of Pb(2+) in river water samples with satisfying results.

A highly selective fluorescent sensor for Cu2+ based on a covalently immobilized naphthalimide derivative.

In this paper, we describe the fabrication and analytical characteristics of fluorescence-based copper ion-sensing glass slides. To construct the sensor, a naphthalimide derivative N-allyl-4-(bis(pyridin-2-ylmethyl)amino)ethylamino-1,8-naphthalimide (1) with a terminal double bond was synthesized and photo-copolymerized with 2-hydroxyethyl methacrylate (HEMA) on a glass surface treated with a silanizing agent. In the presence of Cu(2+) at pH 7.24, the resulting optical sensor undergoes fluorescence quenching. Thus, the proposed sensor with visible excitation can behave as a fluorescent sensor for the selective detection of Cu(2+). In addition, the sensor exhibits satisfactory selectivity, reproducibility and response time. The sensing membrane possesses a relatively long lifetime of at least 2 months. The linear response range covers a concentration range of Cu(2+) from 4.0 x 10(-7) to 6.0 x 10(-4) mol/L and the detection limit is 2.0 x 10(-7) mol/L. The determination of Cu(2+) in river water samples shows satisfactory results.

A highly selective fluorescent probe for Hg(2+) based on a rhodamine-coumarin conjugate.

A fluorescent probe 1 for Hg(2+) based on a rhodamine-coumarin conjugate was designed and synthesized. Probe 1 exhibits high sensitivity and selectivity for sensing Hg(2+), and about a 24-fold increase in fluorescence emission intensity is observed upon binding excess Hg(2+) in 50% water/ethanol buffered at pH 7.24. The fluorescence response to Hg(2+) is attributed to the 1:1 complex formation between probe 1 and Hg(2+), which has been utilized as the basis for the selective detection of Hg(2+). Besides, probe 1 was also found to show a reversible dual chromo- and fluorogenic response toward Hg(2+) likely due to the chelation-induced ring opening of rhodamine spirolactam. The analytical performance characteristics of the proposed Hg(2+)-sensitive probe were investigated. The linear response range covers a concentration range of Hg(2+) from 8.0x10(-8) to 1.0x10(-5)molL(-1) and the detection limit is 4.0x10(-8)molL(-1). The determination of Hg(2+) in both tap and river water samples displays satisfactory results.

A ratiometric fluorescent sensor for zinc ions based on covalently immobilized derivative of benzoxazole.

In the present paper, we describe the fabrication and analytical characteristics of fluorescence-based zinc ion-sensing glass slides. To construct the sensor, a benzoxazole derivative 4-benzoxazol-2'-yl-3-hydroxyphenyl allyl ether (1) with a terminal double bond was synthesized and copolymerized with 2-hydroxyethyl methacrylate (HEMA) on the activated surface of glass slides by UV irradiation. In the absence of Zn(2+) at pH 7.24, the resulting optical sensor emitted fluorescence at 450 nm via excited-state intramolecular proton transfer (ESIPT). Upon binding with Zn(2+), the ESIPT process was inhibited resulting in a 46 nm blue-shift of fluorescence emission. Thus, the proposed sensor can behave as a ratiometric fluorescent sensor for the selective detection of Zn(2+). In addition, the sensor shows nice selectivity, good reproducibility and fast response time. Cd(2+) did not interfere with Zn(2+) sensing. The sensing membrane demonstrates a good stability with a lifetime of at least 3 months. The linear response range covers a concentration range of Zn(2+) from 8.0x10(-5) to 4.0x10(-3) mol/L and the detection limit is 4.0x10(-5) mol/L. The determination of Zn(2+) in both tap and river water samples shows satisfactory results.