Recent advances in functional nucleic acid decorated nanomaterials for cancer imaging and therapy.

Nanomaterials possess unusual physicochemical properties including unique optical, magnetic, electronic properties, and large surface-to-volume ratio. However, nanomaterials face some challenges when they were applied in the field of biomedicine. For example, some nanomaterials suffer from the limitations such as poor selectivity and biocompatibility, low stability, and solubility. To address the above-mentioned obstacles, functional nucleic acid has been widely served as a powerful and versatile ligand for modifying nanomaterials because of their unique characteristics, such as ease of modification, excellent biocompatibility, high stability, predictable intermolecular interaction and recognition ability. The functionally integrating functional nucleic acid with nanomaterials has produced various kinds of nanocomposites and recent advances in applications of functional nucleic acid decorated nanomaterials for cancer imaging and therapy were summarized in this review. Further, we offer an insight into the future challenges and perspectives of functional nucleic acid decorated nanomaterials.

Additional cytogenetic abnormalities in patients with newly diagnosed acute promyelocytic leukemia predict inferior event-free survival.

BACKGROUND: The innovative combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has established a new chapter of curative approach in acute promyelocytic leukemia (APL). The disease characteristics and prognostic influence of additional cytogenetic abnormalities (ACA) in APL with modern therapeutic strategy need to be elucidated. METHODS: In the present study, we retrospectively investigated disease features and prognostic power of ACA in 171 APL patients treated with ATRA-ATO-containing regimens. RESULTS: Patients with ACA had markedly decreased hemoglobin levels than that without ACA (p = 0.021). Risk stratification in the ACA group was significantly worse than that in the non-ACA group (p = 0.032). With a median follow-up period of 62.0 months, worse event-free survival (EFS) was demonstrated in patients harboring ACA. Multivariate analysis showed that ACA was an independent adverse factor for EFS (p = 0.033). By further subgroup analysis, in CD34 and CD56 negative APL, patients harboring ACA had inferior EFS (p = 0.017; p = 0.037). CONCLUSIONS: To sum up, ACA remains the independent prognostic value for EFS, we should build risk-adapted therapeutic strategies in the long-term management of APL when such abnormalities are detected.

Boronate carbon nanoparticles featuring efficient FRET for activatable two-photon fluorescence imaging of sialic acid surface-abundant tumor cells.

Two-photon carbon-based nanoprobes hold great potential for biomedical applications as a result of their advantages of low fluorescence background, deep tissue imaging penetration and enhanced spatial resolution. However, the development of an activatable two-photon fluorescence carbon-based nanoprobe that simultaneously has the ability to target desired organs or cells is highly desired but remained a largely unsolved challenge. Herein, we developed boronate affinity BCNP@MnO2 nanocomposites, constructed by one step in situ growth of MnO2 nanosheets on the surface of aminophenylboronic acid-functionalized CNPs (BCNPs) via a redox reaction, which can feature efficient fluorescence energy transfer quenching to the BCNPs, allowing for tumor-specific affinity recognition and two-photon fluorescence activation imaging. By utilizing the inherent two-photon optical properties and sialic acid (SA) specific targeting ability of the BCNPs, good biocompatibility of the nanocomposites as well as highly sensitive and selective responses of MnO2 nanosheets towards GSH, the developed nanocomposites have demonstrated specific two-photon fluorescence activation imaging in target cancer cells and nude mouse tissues. Therefore, our proposed novel strategy could be used for monitoring GSH-triggered two-photon fluorescence activation events in SA-overexpressed cancer cells and has promising applications in both biological exploration and clinical diagnosis.

DNAzyme cascade circuits in highly integrated DNA nanomachines for sensitive microRNAs imaging in living cells.

DNA molecular probes have emerged as powerful tools for fluorescence imaging of microRNAs (miRNAs) in living cells and thus elucidating functions and dynamics of miRNAs. In particular, the highly integrated DNA probes that can be able to address the robustness, sensitivity and consistency issues in a single assay system were highly desired but remained largely unsolved challenge. Herein, we reported for the first time that the development of the novel DNA nanomachines that split-DNAzyme motif was highly integrated in a single DNA triangular prism (DTP) reactor and can undergo target-activated DNAzyme catalytic cascade circuits, allowing amplified sensing and imaging of tumor-related microRNA-21 (miR-21) in living cells. The DNA nanomachines have shown dynamic responses for target miR-21 with excellent sensitivity and selectivity and demonstrated the potential for living cell imaging of miR-21. With the advantages of facile modular design and assembly, high biostability, low cytotoxicity and excellent cellular internalization, the highly integrated DNA nanomachines enabled accurate and effective monitoring of miR-21 expression levels in living cells. Therefore, our developed strategy may afford a reliable and robust nanoplatform for tumor diagnosis and for related biological research.

A tumour mRNA-triggered nanoassembly for enhanced fluorescence imaging-guided photodynamic therapy.

A multifunctional theranostic nanoplatform, which integrates diagnostic and therapeutic functions in a single nanosystem, holds great promise for guiding disease treatment and improving the corresponding therapy efficacy. We report the development of a novel g-C3N4 nanosheet-based theranostic nanoassembly for both enhanced imaging of cancer-relevant mRNA in living cells and imaging-guided on-demand photodynamic therapy (PDT) for tumors. The nanoassembly was constructed by using highly fluorescent and water-dispersible g-C3N4 nanosheets which act as nanocarriers, enabling efficient and self-tracking transfection of the DNA hairpin probes. The presence of intracellular mRNA will initiate the DNA hairpin probes, ultimately resulting in an amplified fluorescence signal via hybridization and displacement with mRNA. Moreover, enhanced fluorescence imaging-guided precise PDT for tumors in living cells was also demonstrated, allowing the selective ablation of tumors without any obvious side effects. Therefore, the developed theranostic approach can provide a promising platform for low-abundance biomarker discovery and early treatment of related diseases.

A bipedal DNA nanowalker fueled by catalytic assembly for imaging of base-excision repairing in living cells.

DNA nanowalkers moving progressively along a prescribed DNA track are useful tools in biosensing, molecular theranostics and biosynthesis. However, stochastic DNA nanowalkers that can perform in living cells have been largely unexplored. We report the development of a novel stochastic bipedal DNA walker that, for the first time, realizes direct intracellular base excision repair (BER) fluorescence activation imaging. In our design, the bipedal walker DNA was generated by BER-related human apurinic/apyrimidinic endonuclease 1 (APE1)-mediated cleavage of DNA sequences at an abasic site in the intracellular environment, and it autonomously travelled on spherical nucleic acid (SNA) surfaces via catalyzed hairpin assembly (CHA). Our nanomachine outperforms the conventional single leg-based DNA walker with an improved sensitivity, kinetics and walking steps. Moreover, in contrast to the single leg-based DNA walker, the bipedal DNA walker is capable of monitoring the fluorescence signal of reduced APE1 activity, thus indicating amplified intracellular imaging. This bipedal DNA-propelled DNA walker presents a simple and modular amplification mechanism for intracellular biomarkers of interest, providing an invaluable platform for low-abundance biomarker discovery leading to the accurate identification and effective treatment of cancers.

DNAzyme activated protein-scaffolded CRISPR-Cas9 nanoassembly for genome editing.

A novel self-assembled protein-scaffolded CRISPR-Cas9 nanosystem for facile and efficient gene editing in a DNAzyme-controlled manner has been developed.

Programmable Self-Assembly of Protein-Scaffolded DNA Nanohydrogels for Tumor-Targeted Imaging and Therapy.

DNA hydrogels are biocompatible and are suitable for many biomedical applications. However, to be useful imaging probes or drug carriers, the ordinary bulk size of DNA hydrogels must be overcome. Here we put forward a new strategy for fabricating a novel and simple protein-scaffolded DNA nanohydrogel, constructed through a direct DNA self-assembly using three types of streptavidin (SA)-based DNA tetrad for the activation of imaging and targeting therapy of cancer cells. The DNA nanohydrogels are easily prepared, and we show that by varying the initial concentration of DNA tetrad, it is possible to finely control their size within nanoscale range, which are favorable as carriers for intracellular imaging and transport. By further incorporating therapeutic agents and tumor-targeting MUC1 aptamer, these multifunctionalized SA-scaffolded DNA nanohydrogels (SDH) can specifically target cancer cells and selectively release the preloaded therapeutic agents via a structure switching when in an ATP-rich intracellular environment, leading to the activation of the fluorescence and efficient treatment of cancer cells. With the advantages of facile modular design and assembly, effective cellular uptake, and excellent biocompatibility, the method reported here has the potential for the development of new tunable DNA nanohydrogels with multiple synergistic functionalities for biological and biomedical applications.

Multivalent Self-Assembled DNA Polymer for Tumor-Targeted Delivery and Live Cell Imaging of Telomerase Activity.

The efficient detection and in situ monitoring of telomerase activity is of great importance for cancer diagnosis and biomedical research. Here we report for the first time that the development of a novel multivalent self-assembled DNA polymer, constructed through telomerase primer sequence (ITS) triggered hybridization chain assembly using two functional hairpin probes (tumor-trageting aptamer modified H1 and signal probe modified H2), for sensitive detection and imaging of telomerase activity in living cells. After internalizing into the tumor cells by multivalent aptamer targeting, the ITS on DNA polymers can be elongated by intracellular telomerase to generate telomere repeat sequences that are complementary with the signal probe, which can proceed along the DNA polymers, and gradually light up the whole DNA polymers, leading to an enhanced fluorescence signal directly correlated with the activity of telomerase. Our results demonstrated that the developed DNA polymer show excellent performance for specifically detecting telomerase activity in cancer cells, dynamically monitoring the activity change of telomerase in response to telomerase-based drugs, and efficiently distinguishing cancer cells from normal cells. The proposed strategy may afford a valuable tool for the monitoring of telomerase activity in living cells and have great implications for biological and diagnostic applications.

Amplified Split Aptamer Sensor Delivered Using Block Copolymer Nanoparticles for Small Molecule Imaging in Living Cells.

We develop a novel amplified split aptamer sensor for highly sensitive detection and imaging of small molecules in living cells by using cationic block copolymer nanoparticles (BCNs) with entrapped fluorescent conjugated polymer as a delivery agent. The design of a split aptamer as the initiator of hybridization chain reaction (HCR) affords the possibility of enhancing the signal-to-background ratio and thus allows high-contrast imaging for small molecules with relatively weak interactions with their aptamers. The novel design of using fluorescent cationic BCNs as the nanocarrier enables efficient and self-tracking transfection of DNA probes. Results reveal that BCNs exhibit high fluorescence brightness allowing direct tracking of the delivery location. The developed amplified split aptamer sensor is shown to have high sensitivity and selectivity for in vitro quantitative detection of adenosine triphosphate (ATP) with a detection limit of 30 nM. Live cell studies show that the sensor provides a "signal on" approach for specific, high-contrast imaging of ATP. The DNA sensor based HCR system may provide a new generally applicable platform for detection and imaging of low-abundance biomarkers.

DNA Polymer Nanoparticles Programmed via Supersandwich Hybridization for Imaging and Therapy of Cancer Cells.

Spherical nucleic acid (SNA) constructs are promising new single entity materials, which possess significant advantages in biological applications. Current SNA-based drug delivery system typically employed single-layered ss- or ds-DNA as the drug carriers, resulting in limited drug payload capacity and disease treatment. To advance corresponding applications, we developed a novel DNA-programmed polymeric SNA, a long concatamer DNA polymer that is uniformly distributed on gold nanoparticles (AuNPs), by self-assembling from two short alternating DNA building blocks upon initiation of immobilized capture probes on AuNPs, through a supersandwich hybridization reaction. The long DNA concatamer of polymeric SNA enables to allow high-capacity loading of bioimaging and therapeutics agents. We demonstrated that both of the fluorescence signals and therapeutic efficacy were effectively inhibited in resultant polymeric SNA. By further modifying with the nucleolin-targeting aptamer AS1411, this polymeric SNA could be specifically internalized into the tumor cells through nucleolin-mediated endocytosis and then interact with endogenous ATP to cause the release of therapeutics agents from long DNA concatamer via a structure switching, leading to the activation of the fluorescence and selective synergistic chemotherapy and photodynamic therapy. This nanostructure can afford a promising targeted drug transport platform for activatable cancer theranostics.

Tumor-selective catalytic nanosystem for activatable theranostics.

A novel tumor-selective catalytic nanosystem that enables efficient chemodynamic therapy (CDT) and activatable fluorescence imaging in H2O2-rich tumor microenvironments has been developed.

Tumor-Targeted Graphitic Carbon Nitride Nanoassembly for Activatable Two-Photon Fluorescence Imaging.

Unique physicochemical characteristics of graphitic carbon nitride (g-CN) nanosheets suit them to be a useful tool for two-photon fluorescence bioimaging. Current g-CN nanosheets based imaging probes typically use the "always-on" design strategies, which may suffer from increased fluorescence background and limited contrast. To advance corresponding applications, g-CN nanosheets based activatable two-photon fluorescence probes remain to be explored. For the first time, we developed an activatable two-photon fluorescence probe, constructed from a nanoassembly of g-CN nanosheets and hyaluronic acid (HA)-gold nanoparticles (HA-AuNPs), for detection and imaging of hyaluronidase (HAase) in cancer cells. The deliberately introduced HA in our design not only functions as the buffering layer for stabilizing AuNPs and inducing corresponding self-assembly on g-CN nanosheets but also as a pilot for targeting HA receptors overexpressed on cancer cell surfaces. Our results show that the developed nanoassembly enables specific detection and activatable imaging of HAase in cancer cells and deep tissues, with superb signal-to-background ratio and high sensitivity. This nanoassembly can afford a promising platform for highly specific and sensitive imaging of HAase and for related cancer diagnosis.

Identification of a New Uncompetitive Inhibitor of Adenosine Deaminase from Endophyte Aspergillus niger sp.

Adenosine deaminase (ADA) is an enzyme widely distributed from bacteria to humans. ADA is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Endophytes are endosymbionts, often bacteria or fungi, which live within plant tissues and internal organs or intercellular space. Endophytes have a broad variety of bioactive metabolites that are used for the identification of novel natural compounds. Here, 54 morphologically distinct endophyte strains were isolated from six plants such as Peganum harmala Linn., Rheum officinale Baill., Gentiana macrophylla Pall., Radix stephaniae tetrandrae, Myrrha, and Equisetum hyemale Linn. The isolated strains were used for the search of ADA inhibitors that resulted in the identification of the strain with the highest inhibition activity, Aspergillus niger sp. Four compounds were isolated from this strain using three-step chromatography procedure, and compound 2 was determined as the compound with the highest inhibition activity of ADA. Based on the results of 1H and 13C NMR spectroscopies, compound 2 was identified as 3-(4-nitrophenyl)-5-phenyl isoxazole. We showed that compound 2 was a new uncompetitive inhibitor of ADA with high cytotoxic effect on HepG2 and SMCC-7721 cells (the IC50 values were 0.347 and 0.380 mM, respectively). These results suggest that endophyte strains serve as promising sources for the identification of ADA inhibitors, and compound 2 could be an effective drug in the cancer treatment.

Enhancement of the Intrinsic Peroxidase-Like Activity of Graphitic Carbon Nitride Nanosheets by ssDNAs and Its Application for Detection of Exosomes.

The present work investigates the capability of single-stranded DNA (ssDNA) in enhancing the intrinsic peroxidase-like activity of the g-C3N4 nanosheets (NSs). We found that ssDNA adsorbed on g-C3N4 NSs could improve the catalytic activity of the nanosheets. The maximum reaction rate of the H2O2-mediated TMB oxidation catalyzed by the ssDNA-NSs hybrid was at least 4 times faster than that obtained with unmodified NSs. The activity enhancement could be attributed to the strong interaction between TMB and ssDNA mediated by electrostatic attraction and aromatic stacking and by both the length and base composition of the ssDNA. The high catalytic activity of the ssDNA-NSs hybrid permitted sensitive colorimetric detection of exosomes if the aptamer against CD63, a surface marker of exosome, was employed in hybrid construction. The sensor recognized the differential expression of CD63 between the exosomes produced by a breast cancer cell line (MCF-7) and a control cell line (MCF-10A). Moreover, a similar trend was detected in the circulating exosomes isolated from the sera samples collected from breast cancer patients and healthy controls. Our work sheds lights on the possibility of using ssDNA to enhance the peroxidase-like activity of nanomaterials and demonstrates the high potential of the ssDNA-NSs hybrid in clinical diagnosis using liquid biopsy.

Antitumor activity of a Rhodococcus sp. Lut0910 isolated from polluted soil.

The actinomycetes strain, lut0910, was isolated from polluted soil and identified as the Rhodococcus species with 99% similarity based on the sequence analysis of 16S recombinant DNA. The extract of this strain demonstrated in vivo and in vitro antitumor activity. The treatment of two human cancer cell lines, hepatocellular carcinoma HepG2 and cervical carcinoma Hela cells, with the lut0910 extract caused the delay in cell propagation in a dose-dependent manner with an IC50 of 73.39 and 33.09 µg/mL, respectively. Also, the oral administration of lut0910 extract to the mice with a solid tumor resulted in the inhibition of tumor growth in comparison with a placebo group. The thymus and spleen indexes were significantly increased in mice groups treated with the lut0910 extract. The histopathological changes of the tumor tissues showed that there were massive necrotic areas in the tumor tissues after treatment with different doses of the lut0910 extract. Our result would provide a new way and potent source for development of new anticancer agent from the polluted environment.

Melanin-Like Nanoquencher on Graphitic Carbon Nitride Nanosheets for Tyrosinase Activity and Inhibitor Assay.

Graphitic C3N4 (g-C3N4) nanosheets are a type of emerging graphene-like carbon-based nanomaterials with high fluorescence and large specific surface areas that hold great potential for biosensor applications. However, current g-C3N4 based biosensors have prevailingly been limited to coordination with metal ions, and it is of great significance to develop new designs for g-C3N4 nanosheets based biosensors toward biomarkers of general interest. We report the development of a novel g-C3N4 nanosheet-based nanosensor strategy for highly sensitive, single-step and label-free detection of tyrosinase (TYR) activity and its inhibitor. This strategy relies on the catalytic oxidation of tyrosine by TYR into melanin-like polymers, which form a nanoassembly on the g-C3N4 nanosheets and quench their fluorescence. This strategy was demonstrated to provide excellent selectivity and superior sensitivity and to enable rapid screening for TYR inhibitors. Therefore, the developed approach might create a useful platform for diagnostics and drugs screening for TYR-based diseases including melanoma cancer.

Inhibitory effects of blockage of intermediate conductance Ca(2+)-activated K (+) channels on proliferation of hepatocellular carcinoma cells.

The roles of intermediate conductance Ca(2+)-activated K(+) channel (IKCa1) in the pathogenesis of hepatocellular carcinoma (HCC) were investigated. Immunohistochemistry and Western blotting were used to detect the expression of IKCa1 protein in 50 HCC and 20 para-carcinoma tissue samples. Real-time PCR was used to detect the transcription level of IKCa1 mRNA in 13 HCC and 11 para-carcinoma tissue samples. The MTT assay was used to measure the function of IKCa1 in human HCC cell line HepG2 in vitro. TRAM-34, a specific blocker of IKCa1, was used to intervene with the function of IKCa1. As compared with para-carcinoma tissue, an over-expression of IKCa1 protein was detected in HCC tissue samples (P<0.05). The mRNA expression level of IKCa1 in HCC tissues was 2.17 times higher than that in para-carcinoma tissues. The proliferation of HepG2 cells was suppressed by TRAM-34 (0.5, 1.0, 2.0 and 4.0 µmol/L) in vitro (P<0.05). Our results suggested that IKCa1 may play a role in the proliferation of human HCC, and IKCa1 blockers may represent a potential therapeutic strategy for HCC.

[Impact of hypocaloric and hypo-nitrogen parenteral nutrition on clinical outcome in postoperative patients: a multi-center randomized controlled trial of 120 cases].

OBJECTIVE: To evaluate the impact of hypocaloric and hypo-nitrogen parenteral nutrition (PN) on infective complication rate, postoperative hospital stay and treatment cost in postoperative period. METHODS: 120 patients with gastrointestinal tumors with the Nutrition Risk Screening (NRS) score of 3 or 4 undergoing radical gastrectomy in 5 hospitals were randomly assigned into 2 equal groups: control group, receiving PN with 30 (28 - 32) kcal x kg(-1) x d(-1) and nitrogen 0.20 (0.19 - 0.21) g x kg(-1) x d(-1) in regular "3 liter bag", and study group receiving calorie of 18 (range 16 - 20) kcal x kg(-1) x d(-1) and nitrogen of 0.10 (0.09 - 0.11) g x kg(-1) x d(-1) with triple chamber bag. PN support was infused continuously for at least six postoperative days through peripheral vein or peripherally inserted central catheter. The differences between these two groups in blood glucose level, infectious complication, phlebitis, systemic inflammatory response syndrome (SIRS), and duration of hospital stay after operation, and treatment cost. All data were evaluated by both intention to treat (ITT) analysis and per protocol (PP) analysis. RESULTS: There were no significant differences in the clinical baseline and operative types between the two groups. ITT analysis showed that the occurrence of hyperglycemia in postoperative period in the control group was 43.3%, significantly much higher than that in the study group (6.6%, P = 0.000). The infectious complication rate of the study group was 3.3%, significantly lower than that of the control group (16.6%, P = 0.0149), the phlebitis rate of the study group was 0.0%, significantly lower than that of the control group (18.3%, P = 0.0005). The SIRS rate of the study group was 25.0%, significantly lower than that of the control group (45.0%, P = 0.0216). PP analysis showed that the postoperative duration of hospital stay of the control group was 14.1 days +/- 5.8 days, significantly longer than that of the study group (12.4 days +/- 4.0 days, P = 0.047), the total PN cost of the study group was 3411.6 +/- 181.1 Yuan RMB, significantly higher than that of the control group (2945 +/- 162 Yuan RMB, P = 0.000); but the total post-operative cost of treatment of the control group was 13156 +/- 3282 Yuan RMB, significantly higher than that of the study group (11 642 +/- 3019 Yuan RMB, P = 0.010); and the time for compounding of the study group was 5.0 min +/- 1.7 min, significantly shorter than that of the control group (15.4 min +/- 3.7 min, P = 0.000). CONCLUSION: Hypocaloric and hypo-nitrogen PN in postoperative days 1 - 6 in patients with scores 3 or 4 decreases the rates of hyperglycemia, infectious complications, phlebitis, and SIRS, shortens the postoperative hospital stay, and lowers the cost of treatment comparing with conventional PN. The use of triple chamber bag shortens the compounding time of PN.