High-Efficiency 3D DNA Walker Immobilized by a DNA Tetrahedral Nanostructure for Fast and Ultrasensitive Electrochemical Detection of MiRNA.

Herein, by directly limiting the reaction space, an ingenious three-dimensional (3D) DNA walker (IDW) with high walking efficiency is developed for rapid and sensitive detection of miRNA. Compared with the traditional DNA walker, the IDW immobilized by the DNA tetrahedral nanostructure (DTN) brings stronger kinetic and thermodynamic favorability resulting from its improved local concentration and space confinement effect, accompanied by a quite faster reaction speed and much better walking efficiency. Once traces of target miRNA-21 react with the prelocked IDW, the IDW could be largely activated and walk on the interface of the electrode to trigger the cleavage of H2 with the assistance of Mg2+, resulting in the release of amounts of methylene blue (MB) labeled on H2 from the electrode surface and the obvious decrease of the electrode signal. Impressively, the IDW reveals a conversion efficiency as high as 9.33 × 108 in 30 min with a much fast reaction speed, which is at least five times beyond that of typical DNA walkers. Therefore, the IDW could address the inherent challenges of the traditional DNA walker easily: slow walking speed and low efficiency. Notably, the IDW as a DNA nanomachine was utilized to construct a sensitive sensing platform for rapid miRNA-21 detection with a limit of detection (LOD) of 19.8 aM and realize the highly sensitive assay of biomarker miRNA-21 in the total RNA lysates of cancer cell. The strategy thus helps in the design of a versatile nucleic acid conversion and signal amplification approach for practical applications in the areas of biosensing assay, DNA nanotechnology, and clinical diagnosis.

Dual 3D DNA Nanomachine-Mediated Catalytic Hairpin Assembly for Ultrasensitive Detection of MicroRNA.

Herein, we designed a dual 3D DNA nanomachine (DDNM)-mediated catalytic hairpin assembly (DDNM-CHA) to construct an electrochemical biosensor for ultrasensitive detection of miRNA, which possesses quite a faster reaction rate and much higher amplification efficiency than those of traditional catalytic hairpin assembly (CHA). Impressively, since the DDNM skillfully increases the local concentration of reactants and decreases the steric hindrance of substrates simultaneously, the DDNM-CHA could be endowed with higher collision efficiency and more effective reaction compared with traditional CHA, resulting in a hyper conversion efficiency up to 2.78 × 107 only in 25 min. This way, the developed DDNM-CHA could easily conquer the main predicaments: long reaction time and low efficiency. As a proof of the concept, we adopt the gold nanoparticles (AuNPs) and the magnetic nanoparticle (Fe3O4) as the kernel of DNM-A and DNM-B, respectively, and harness the magnetic electrode to directly adsorb the products H1-H2/Fe3O4 for constructing an immobilization-free biosensor for high-speed and ultrasensitive detection of miRNA with a detection limit of 0.14 fM. As a result, the DDNM-CHA we developed carves out a new insight to design a functional DNA nanomachine and evolve the analysis method for practical amplification in the sensing area and promotes the deeper exploration of the nucleic acid signal amplification strategy and DNA nanobiotechnology.

Engineering a Rolling-Circle Strand Displacement Amplification Mediated Label-Free Ultrasensitive Electrochemical Biosensing Platform.

In this work, an original rolling-circle strand displacement amplification (RC-SDA) was developed by introducing a circle DNA with two recognition domains as a template instead of the limited liner DNA template in traditional strand displacement amplification (SDA), which displayed much shorter reaction time down to 30 min and quite higher conversion efficiency of more than 1.77 × 108 compared with those of traditional strand displacement amplification (SDA) and could be applied to construct a label-free biosensor for ultrasensitive detection of an HIV DNA fragment. Once the target HIV DNA fragment interacts with the template circle DNA, the RC-SDA could be activated to dramatically output amounts of mimic target DNA with the assistance of the Phi29 DNA polymerase and Nb.BbvCI enzyme. In application, while the output products were captured by the DNA tetrahedral nanoprobe (DTNP) modified electrode, the electrochemical tag silver nanoclusters (AgNCs) on DTNP would be released from the electrode surface, accompanied with an obviously decreased electrochemical signal. This way, the developed signal-off biosensor was successfully applied to realize the rapid and ultrasensitive detection of target HIV DNA fragment with a detection limit down to 0.21 fM, which exploits the new generation of a universal strategy beyond the traditional ones for applications in biosensing assay, clinic diagnosis, and DNA nanobiotechnology.

Synthesis and antitumor activity of α,ß-unsaturated carbonyl moiety- containing oleanolic acid derivatives targeting PI3K/AKT/mTOR signaling pathway.

Oleanolic acid (OA) and its semi-synthetic derivatives have been reported to have a wide range of biological activities. The introduction of electrophilic Michael acceptor group can increase the reactivity of OA to cellular targets and thus improve the anti-tumor activity. In this work, a series of novel α,ß-unsaturated carbonyl derivatives of OA were designed and synthesized. Their in vitro cytotoxic activity against MCF-7, HepG2 and HeLa cells were tested. Most derivatives exhibited improved cell growth inhibitory activity, especially for 3d with an IC50 of 0.77 µM in MCF-7 cells. Moreover, 3d inhibited the migration of MCF-7 and HeLa cells at the concentration of 4 µM. Flow cytometric analysis revealed that 3d induced cell apoptosis and S phase arrest in a concentration-dependent manner. Western blotting experiment demonstrated that 3d inhibited the phosphorylation of AKT and mTOR. These results suggest that this series of OA derivatives bearing exocyclic methylene ketone pharmacophore are promising anticancer agents as potential PI3K/AKT/mTOR pathway inhibitors.

Programmable mismatch-fueled high-efficiency DNA signal amplifier.

Herein, by introducing mismatches, a high-efficiency mismatch-fueled catalytic multiple-arm DNA junction assembly (M-CMDJA) with high-reactivity and a high-threshold is developed as a programmable DNA signal amplifier for rapid detection and ultrasensitive intracellular imaging of miRNA. Compared with traditional nucleic acid signal amplification (NASA) with a perfect complement, the M-CMDJA possesses larger kinetic and thermodynamic favorability owing to the more negative reaction standard free energy (ΔG) as driving force, resulting in much higher efficiency and rates. Once traces of the input initiator react with the mismatched substrate DNA, it could be converted into amounts of output multiple-arm DNA junctions via the M-CMDJA as the functional DNA conversion nanodevice. Impressively, the mismatch-fueled catalytic four-arm DNA junction assembly (M-CFDJA) exhibits high conversion efficiency up to 1.05 × 108 in 30 min, which is almost ten times more than those of conventional methods. Therefore, the M-CMDJA could easily address the challenges of traditional methods: slow rates and low efficiency. In application, the M-CFDJA as a DNA signal amplifier was successfully used to develop a biosensing platform for rapid miRNA detection with a LOD of 6.11 aM and the ultrasensitive intracellular imaging of miRNA, providing a basis for the next-generation of versatile DNA signal amplification methods for ultimate applications in DNA nanobiotechnology, biosensing assay, and clinical diagnoses.

Research Progress on Structure and Anti-Gynecological Malignant Tumor of Shikonin.

Gynecological malignancy seriously threatens the physical and mental health of women. Shikonin is a naphthoquinone compound with a variety of biological activities. Studies have shown that shikonin can inhibit cell proliferation, promote cell apoptosis and induce cell necrosis. And in recent years, shikonin are also being increasingly used for the study of gynecological malignant diseases. Therefore, we reviewed the mechanism of action and structure optimization of shikonin in gynecological malignant tumors, in order to provide some reference for further research and development of related drug.

Synthesis and Anticancer Activity of Rhopaladins' Analog RPDPD Against the HeLa Human Cervical Cancer Cell Line.

Heterocyclic compounds were widely used in many domains; pyrrolidone is a derivative of heterocycles that can be used to synthesize anticancer drugs. A new fluorine-containing rhopaladins' analog(E)-2-(4-bromobenzoyl)-N-(tert-butyl)-4-(4-fluoro benzylidene)-5-oxo-1-propylpyrrolidine-2-carboxamide (RPDPD for short) of 2-aroyl-4-arylidene-5-oxopyrrolidine derivative was synthesized by the one-pot synthesis method and evaluated for its anti-tumor activity in vitro via CCK8 assay and annexin V/propidium iodide (PI) staining of HeLa cells. The results exhibited that compound RPDPD has inhibited the proliferation of HeLa in a dose-dependent manner with an IC50 of 24.23 µmol/L (p < 0.05) and has low hepatotoxicity with an IC50 of 235.6 µmol/L (p < 0.05) to normal hepatocyte LO2 cells. The apoptotic assay demonstrated that compound RPDPD has induced apoptosis in HeLa cells (from 14.26 to 23.4%, p < 0.05). qRT-PCR results showed that the compound RPDPD could inhibit the expression of oncogene E6/E7 mRNA (p < 0.05) of human papillomavirus (HPV). The results of Western blot showed that the compound RPDPD promoted the expression of TIMP3 protein and inhibited the expression of MMP3 (p < 0.05). In conclusion, the compound RPDPD can inhibit the proliferation of cervical cancer cells and induce the apoptosis of cervical cancer cells, and its mechanism may be related to the inhibition of E6 mRNA and E7 mRNA expressions, and the anticancer effect of the compound RPDPD on cervical cancer is closely related to the TIMP3/MMP3 signaling axis.

Green synthesis, crystal structure, and antifungal activities of (E)-4-arylidene-5-oxotetrahydrofuran.

A series of γ-lactone derivatives (E)-4-arylidene-5-oxotetrahydrofuran derivatives were synthesized via a tandem Passerini 3CC/SN cyclization microwave-assisted one-pot method efficiently starting from Baylis Hillman acids, aryl glyoxals and isocyanides, and using ionic liquid as reaction medium. The products were characterized by hydrogen nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR). Single crystal X-ray analysis of the compound RPDFB clearly confirmed its assigned chemical structures. Meanwhile, the effects of four compounds (RPDFB, RPDFC, RPDFI, RPDFJ) on the growth inhibition activity of Gibberella zeae were detected, and found that the compound RPDFB has significant growth inhibition activity to Gibberella zeae.

Programmable High-Speed and Hyper-Efficiency DNA Signal Magnifier.

Herein, a programmable dual-catalyst hairpin assembly (DCHA) for realizing the synchronous recycle of two catalysts is developed, displaying high reaction rate and outstanding conversion efficiency beyond traditional nucleic acid signal amplifications (NASA). Once catalyst I interacts with the catalyst II, the DCHA can be triggered to realize the simultaneous recycle of catalysts I and II to keep the highly concentrated intermediate product duplex I-II instead of the steadily decreased one in typical NASA, which can accomplish in about only 16 min and achieves the outstanding conversion efficiency up to 4.54 × 108 , easily conquering the main predicaments of NASA: time-consuming and low-efficiency. As a proof of the concept, the proposed DCHA as a high-speed and hyper-efficiency DNA signal magnifier is successfully applied in the rapid and ultrasensitive detection of miRNA-21 in cancer cell lysates, which exploits the new generation of universal strategy for the applications in biosensing assay, clinic diagnose, and DNA nanobiotechnology.

Green synthesis, structure optimization and biological evalution of Rhopaladins' analog 2-styryl-5-oxopyrrolidine-2- carboxamide RPDPRH on CaSki cells.

We have synthesized Rhopaladins' analog (2E,4E)-4-chlorobenzylidene-2-(4-chlorostyryl)-N-cyclohexyl-1-(4-fluorophenyl)-5-oxopyrrolidine-2-carboxamide (RPDPRH) via a highly facile, inexpensive and green approach and verified the structural superiority of compound RPDPRH through molecular docking. Moreover, we further detected the anti-proliferation, apoptosis and HPV E6/E7 effects of RPDPRH on CaSki cells. Finally, we confirmed that compared with the previous compound (E)-N-(tert-butyl)-2-(4-chlorobenzoyl)-4-(4-fluorobenzylidene)-1-isopropyl-5-oxopyrrolidine-2-carboxamide (RPDPB), RPDPRH could better inhibit proliferation, induce apoptosis, and down-regulate HPV E6/E7 mRNA expression on Caski cells. And preliminary RT-PCR experiments have demonstrated that RPDPRH also could affect the expression of Bcl-2, Bax and Caspase-3 mRNA in Caski cells. In summary, RPDPRH has potential as an effective agent against cervical cancer and will play an important role in our subsequent research.

Design, Synthesis, and Apoptosis-Promoting Effect Evaluation of Rhopaladins' Analog 4-Arylidene-5-Oxopyrrolidine Derivatives.

Marine alkaloids have novel structures and antitumor activities. Therefore, we synthesized rhopaladins' analogs from marine alkaloids rhopaladins A-D and modified their structures to synthesize 4-benzylidene-5-pyrrolidone derivatives. Among the compounds, (2E, 4E)-4-(4-chlorobenzylidene)-2-(4-chlorostyryl)-N-cyclohexyl-1-(4-fluorophenyl)-5-oxopyrrolidine-2-carboxamide (RPDPRH) has high efficiency and less hepatotoxicity, with IC50 values of 4.66, 6.42, 17.66, 15.2, 12.36, 22.4, and 243.2 µM in vitro anti-proliferative activity testing against cervical cancer C-33A, CaSki, SiHa, and HeLa cells, human hepatocarcinoma HepG2 and 7402 cells, and human normal liver LO2 cells, respectively. In particular, RPDPRH has similar activity to cisplatin on human hepatocarcinoma cells, and cisplatin served as a positive control in our study. Next, the apoptosis of HepG2 and 7402 cells induced by RPDPRH at different concentrations was detected by Annexin V/PI flow cytometry. Moreover, the expression of apoptotic proteins was detected by Western blot analysis. Finally, the results showed that RPDPRH could induce apoptosis of hepatocarcinoma cells by regulating Bax and Bcl-2 expressions. In summary, our results indicate that RPDPRH has the potential to serve as an antitumor agent and plays a significant role in future studies.

Improvements in the intraluminal thread technique to induce focal cerebral ischaemia in rabbits.

Although the intraluminal thread technique has been used to induce focal cerebral ischaemia in rabbits, its success rate is not high. We, therefore, attempted to improve the stability and reproducibility of this method by using thread tips of appropriate diameter as determined from the anatomical characteristics of the carotid and cerebral arteries of New Zealand white rabbits. Following intraarterial injection of casting material, we tested threads of four different tip diameters to determine the optimal thread tip that could occlude the middle cerebral artery (MCA). 2,3,5-Triphenyltertrazolium chloride (TTC) staining showed that, consistent with the intraluminal diameter of the MCA from the arterial casts ( 0.50 +/- 0.06 mm), thread with 0.51-0.55 mm tip diameter was optimal for the occlusion of the MCA. Ability to induce focal cerebral ischaemia was also dependent on variations in the anatomy of the internal carotid artery (ICA), especially the origin of the occipital artery. Our results suggest that use of appropriately sized thread and accurate manipulation of its tip significantly improves the stability and reproducibility of this model.