Honokiol Suppresses Cell Proliferation and Tumor Migration through ROS in Human Anaplastic Thyroid Cancer Cells.

BACKGROUND: Honokiol is a natural polyphenolic compound extracted from Magnolia officinali, which is commonly used material in Chinese herbal medicine, has a variety of biological functions, including anti-tumor, anti-oxidant, anti-inflammation, anti-microbial and anti-allergy. Although honokiol has numerous beneficial effects on human diseases, the underlying mechanisms of tumor metastasis are still unclear. Previously, we reported that honokiol suppresses thyroid cancer cell proliferation with cytotoxicity through cell cycle arrest, apoptosis, and dysregulation of intracellular hemostasis. Herein, we hypothesized that the antioxidant effect of honokiol might play a critical role in thyroid cancer cell proliferation and migration. METHODS: The cell viability assays, cellular reactive oxygen species (ROS) activity, cell migration, and immunoblotting were performed after cells were treated with honokiol. RESULTS: Based on this hypothesis, we first demonstrated that honokiol suppresses cell proliferation in two human anaplastic thyroid carcinoma (ATC) cell lines, KMH-2 and ASH-3, within a dosage- and time-dependent manner by cell counting kit-8 (CCK-8) assay. Next, we examined that honokiol induced ROS activation and could be suppressed by pre-treated with an antioxidant agent, N-acetyl-l-cysteine (NAC). Furthermore, the honokiol suppressed cell proliferation can be rescued by pre-treated with NAC. Finally, we demonstrated that honokiol inhibited ATC cell migration by modulating epithelial-mesenchymal transition (EMT)-related markers by Western blotting. CONCLUSION: Taken together, we provided the potential mechanism for treating ATC cells with honokiol, which significantly suppresses tumor proliferation and inhibits tumor metastasis in vitro through reactive oxygen species (ROS) induction.

Fabrication and characterization of coated microneedle patches based on PEGDA for transdermal administration of metformin.

Type 2 diabetes is one of the major challenges that the world is facing today. However, metformin (MET) as most type 2 diabetics' first-line oral hypoglycemic drug may cause serious side effects such as gastrointestinal irritation and nausea which reduce the patients' medication compliance. Therefore, the aim of the study was to design a safe and effective self-treatment device for the delivery of MET. Here, a kind of coated microneedle (MN) patches based on poly(ethylene glycol)diacrylate (PEGDA) were prepared by a two-step casting method and photopolymerization process for transdermal administration of MET. The needles wrapped with drug-loaded hyaluronic acid (HA) coating showed promising mechanical properties and drug delivery ability that allowed them to penetrate the skin barrier for rapid drug delivery, and they had no skin irritancy. The in vivo experiment of type 2 diabetic rats showed a satisfying hypoglycemic effect of the coated MN patches. The study shows that the prepared MN patches will be a potential method for the treatment of type 2 diabetes in the future.

Histone deacetylase III interactions with BK polyomavirus large tumor antigen may affect protein stability.

BACKGROUND: Human polyomavirus BK (BKPyV) causes associated nephropathy and contributes to urinary tract cancer development in renal transplant recipients. Large tumor antigen (LT) is an early protein essential in the polyomavirus life cycle. Protein acetylation plays a critical role in regulating protein stability, so this study investigated the acetylation of the BKPyV LT protein. METHODS: The BKPyV LT nucleotide was synthesized, and the protein was expressed by transfection into permissive cells. The BKPyV LT protein was immunoprecipitated and subjected to LC-MS/MS analysis to determine the acetylation residues. The relative lysine was then mutated to arginine in the LT nucleotide and BKPyV genome to analyze the role of LT lysine acetylation in the BKPyV life cycle. RESULTS: BKPyV LT acetylation sites were identified at Lys3 and Lys230 by mass spectrometry. HDAC3 and HDAC8 and their deacetylation activity are required for BKPyV LT expression. In addition, mutations of Lys3 and Lys230 to arginine increased LT expression, and the interaction of HDAC3 and LT was confirmed by coimmunoprecipitation. CONCLUSIONS: HDAC3 is a newly identified protein that interacts with BKPyV LT, and LT acetylation plays a vital role in the BKPyV life cycle.

A multi-crosslinking strategy of organic and inorganic compound bio-adhesive polysaccharide-based hydrogel for wound hemostasis.

Polysaccharides are naturally occurring polymers with exceptional biodegradable and biocompatible qualities that are used as hemostatic agents. In this study, photoinduced CC bond network and dynamic bond network binding was used to give polysaccharide-based hydrogels the requisite mechanical strength and tissue adhesion. The designed hydrogel was composed of modified carboxymethyl chitosan (CMCS-MA) and oxidized dextran (OD), and introduced hydrogen bond network through tannic acid (TA) doping. Halloysite nanotubes (HNTs) were also added, and the effects of various doping amount on the performance of the hydrogel were examined, in order to enhance the hemostatic property of hydrogel. Experiments on vitro degradation and swelling demonstrated the strong structural stability of hydrogels. The hydrogel has improved tissue adhesion strength, with a maximum adhesion strength of 157.9 kPa, and demonstrated improved compressive strength, with a maximum compressive strength of 80.9 kPa. Meanwhile, the hydrogel had a low hemolysis rate and had no inhibition on cell proliferation. The created hydrogel exhibited a significant aggregation effect on platelets and a reduced blood clotting index (BCI). Importantly, the hydrogel can quickly adhere to seal the wound and has good hemostatic effect in vivo. Our work successfully prepared a polysaccharide-based bio-adhesive hydrogel dressing with stable structure, appropriate mechanical strength, and good hemostatic properties.

In situ photo-crosslinking silk fibroin based hydrogel accelerates diabetic wound healing through antibacterial and antioxidant.

Bacterial infection and excessive reactive oxygen species (ROS) in diabetic wounds lead to a prolonged inflammatory phase, and injuries are highly susceptible to developing into chronic wounds. Improving the poor microenvironment is vital to achieving effective diabetic wound healing. In this work, methacrylated silk fibroin (SFMA) was combined with ε-polylysine (EPL) and manganese dioxide nanoparticles (BMNPs) to form an SF@(EPL-BM) hydrogel with in situ forming, antibacterial and antioxidant properties. EPL imparted high antibacterial activity (>96 %) to the hydrogel. BMNPs and EPL showed good scavenging activity against a variety of free radicals. SF@(EPL-BM) hydrogel had low cytotoxicity and could alleviate H2O2-induced oxidative stress in L929 cells. In diabetic wounds infected with Staphylococcus aureus (S. aureus), the SF@(EPL-BM) hydrogel exhibited better antibacterial properties and reduced wound ROS levels more significantly than that of the control in vivo. In this process, the pro-inflammatory factor TNF-α was down-regulated, and the vascularization marker CD31 was up-regulated. H&E and Masson staining showed a rapid transition from the inflammatory to the proliferative phase of the wounds, with significant new tissue and collagen deposition. These results confirm that this multifunctional hydrogel dressing holds well potential for chronic wound healing.

Microperoxidase-11 functionalized nanozyme with enhanced peroxidase-mimicking activities for visual detection of cysteine.

Various nanomaterials with peroxidase activity (nanozyme) have been designed for bio catalysis and biosensing, however, most of them need further design and modification of probe molecules for the specific binding reaction with targets. This results in a decrease in catalysis activity and hinders them to be perfect alternatives to natural enzyme in biosensing. In this work, an enhanced nanozyme was synthesized by functionalizing natural microperoxidase-11 (MP-11) on a hybrid graphene oxide-gold (GO-Au) material. The designed nanozyme showed an enhanced catalysis activity and realized a robust and efficient colorimetric detection of cysteine based on specific binding reaction between active iron center from MP-11 and thiol in cysteine. The enhanced properties show promising applications of complex nanozyme and provides a great opportunity for developing efficient sensing systems.

Artesunate Exhibits Synergy With Cisplatin and Cytotoxicity for Upper Tract and Bladder Urothelial Carcinoma Cells.

BACKGROUND/AIM: Urothelial carcinoma (UC) may arise from the urothelium of the upper tract and the bladder. Cisplatin-based therapy remains the gold standard for UC treatment. The poor 5-year survival rate of UC patients creates an urgent need to develop new drugs for advanced UC therapy. Artesunate (ART), a traditional Chinese medicine for treating malaria, is a potential anticancer agent, but its antigrowth effects on upper tract and bladder UC have not been investigated. MATERIALS AND METHODS: The antigrowth effect of ART in HT 1376 (bladder UC cells) and BFTC 909 [upper tract urothelial carcinoma (UTUC) cells] was determined by the CCK-8 assay. Flow cytometric analysis was used to evaluate the cell cycle distribution and apoptosis. The cell cycle, apoptosis, and autophagy-related protein expression were analyzed by western blotting. The efficacy of combination treatment with cisplatin was determined by the Calcusyn software. RESULTS: ART induced HT 1376 and BFTC 909 cell death in a concentration- and time-dependent manner, inducing G2/M cell-cycle arrest. ART induced apoptosis and redox imbalance in HT 1376 and BFTC 909 cells. Application of the reactive oxygen species (ROS) scavenger, N-acetyl-L-cysteine (NAC), attenuated cell death in ART-treated UC cells. BFTC 909 cells show a better response after ART treatment. CONCLUSION: ART may be a candidate drug for treating UTUC and bladder UC while increasing the therapeutic effect of cisplatin.

Ivermectin induces cell cycle arrest and caspase-dependent apoptosis in human urothelial carcinoma cells.

Bladder carcinoma is one of the most common malignancies worldwide, and >90% of all bladder cancers are classified as urothelial carcinomas (UC). Surgery, radiotherapy, chemotherapy, targeted therapy, and immunotherapy are evidence-based treatments that are administered depending on the clinical stage of UC. All these treatments exhibited limited effects in cases of metastatic UC, and UC with specific location, invasiveness, and recurrence. Therefore, a new therapeutic strategy for UC is urgently needed. Ivermectin, an avermectin derivative, has been reported to be effective against various parasites, and its pharmacokinetic and pharmacodynamic properties as well as safety are well understood in humans. Recently, ivermectin was shown to exhibit therapeutic benefits against various virus infections in vitro, and anticancer activity against various human cancer cells. This study aimed to investigate the anticancer effects of ivermectin in human UC cells. Ivermectin inhibited growth, regulated the cell cycle, and induced apoptosis in human UC cells. It also induced the activation of both extrinsic and intrinsic caspase-dependent apoptotic pathways. Further investigation revealed that ivermectin induced apoptosis in UC cells is mediated via c-Jun N-terminal kinase signaling. Herein, we demonstrated that ivermectin can be used as a new therapeutic agent for treating UC cells.

Xin-Ji-Er-Kang protects heart from ischemia-reperfusion injury by rebalancing lipid metabolism.

Background and Purpose: We have previously reported a cardioprotective effect with Xin-Ji-Er-Kang (XJEK) treatment in mice with myocardial infarction (MI)-induced heart failure, but no report about its potential functions in myocardial ischemia-reperfusion (MIR) injury. Here we studied the therapeutic effects of XJEK on MIR injury and investigated the mechanisms involved. Experimental Approach: MIR model of Balb/c mice induced by left anterior descending coronary artery ligation for half an hour, followed by reperfusion, was utilized to study the potential therapeutic effects of XJEK on MIR-induced cardiac injury. Ultra-performance liquid chromatography tandem Orbitrap mass spectrometry platform was used for studying serum lipid metabolic signatures. Key Results: MIR caused cardiac dysfunctions, cardiac injury, myocardial fibrosis, and increased inflammation, and all the observed abnormalities caused by MIR were largely corrected by XJEK treatment. Mechanistically, XJEK exerts its cardioprotective effect in the context of MIR injury by suppressing MIR-induced inflammation and dysregulation of serum lipid metabolism. Conclusion and Implications: We have demonstrated for the first time that XJEK protects heart from MIR injury by restoring dysregulated lipidomics. Our data provide new evidence to support a therapeutic effect for XIEK on MIR-induced cardiac injury, and pave the way for exploring the therapeutic potential of XJEK in large animal study and early clinical trial.

Novel Insights into the Cardioprotective Effects of Calcitriol in Myocardial Infarction.

BACKGROUND: Increasing evidence indicates that vitamin D deficiency negatively affects the cardiovascular system. Here we studied the therapeutic effects of calcitriol in myocardial infarction (MI) and investigated its underlying mechanisms. METHODS: A MI model of Kun-ming mice induced by left anterior descending coronary artery ligation was utilized to study the potential therapeutic effects of calcitriol on MI. AC16 human cardiomyocyte-like cells treated with TNF-α were used for exploring the mechanisms that underlie the cardioprotective effects of calcitriol. RESULTS: We observed that calcitriol reversed adverse cardiovascular function and cardiac remodeling in post-MI mice. Mechanistically, calcitriol suppressed MI-induced cardiac inflammation, ameliorated cardiomyocyte death, and promoted cardiomyocyte proliferation. Specifically, calcitriol exerted these cellular effects by upregulating Vitamin D receptor (VDR). Increased VDR directly interacted with p65 and retained p65 in cytoplasm, thereby dampening NF-κB signaling and suppressing inflammation. Moreover, up-regulated VDR was translocated into nuclei where it directly bound to IL-10 gene promoters to activate IL-10 gene transcription, further inhibiting inflammation. CONCLUSION: We provide new insights into the cellular and molecular mechanisms underlying the cardioprotective effects of calcitriol, and we present comprehensive evidence to support the preventive and therapeutic effects of calcitriol on MI.

9-O-Terpenyl-Substituted Berberrubine Derivatives Suppress Tumor Migration and Increase Anti-Human Non-Small-Cell Lung Cancer Activity.

Lung cancer is one of the most common cancers and the leading cause of death in humans worldwide. Non-small-cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer cases and is often diagnosed at a late stage. Among patients with NSCLC, 50% die within 1 year after diagnosis. Even with clinical intervention, the 5-year survival rate is only approximately 20%. Therefore, the development of an advanced therapeutic strategy or novel agent is urgently required for treating NSCLC. Berberine exerts therapeutic activity toward NSCLC; therefore, its activity as an antitumor agent needs to be explored further. In this study, three terpenylated-bromide derivatives of berberrubine were synthesized and their anti-NSCLC activities were evaluated. Each derivative had higher anti-NSCLCs activity than berberrubine and berberine. Among them, 9-O-gernylberberrubine bromide (B4) and 9-O-farnesylberberrubine bromide (B5) showed greater growth inhibition, cell-cycle regulation, in vitro tumorigenesis suppression, and tumor migration reduction. In addition, some degree of apoptosis and autophagic flux blocking was noted in the cells under B4 and B5 treatments. Our study demonstrates that the berberrubine derivatives, B4 and B5, exhibit impressive anti-NSCLC activities and have potential for use as chemotherapeutic agents against NSCLC.

Piperlongumine, a Potent Anticancer Phytotherapeutic, Induces Cell Cycle Arrest and Apoptosis In Vitro and In Vivo through the ROS/Akt Pathway in Human Thyroid Cancer Cells.

Thyroid cancer (TC) is the most common endocrine malignancy, and its global incidence has steadily increased over the past 15 years. TC is broadly divided into well-differentiated, poorly differentiated, and undifferentiated types, depending on the histological and clinical parameters. Thus far, there are no effective treatments for undifferentiated thyroid cancers or advanced and recurrent cancer. Therefore, the development of an effective therapeutic is urgently needed for such patients. Piperlongumine (PL) is a naturally occurring small molecule derived from long pepper; it is selectively toxic to cancer cells by generating reactive oxygen species (ROS). In this study, we demonstrate the potential anticancer activity of PL in four TC cell lines. For this purpose, we cultured TC cell lines and analyzed the following parameters: Cell viability, colony formation, cell cycle, apoptosis, and cellular ROS induction. PL modulated the cell cycle, induced apoptosis, and suppressed tumorigenesis in TC cell lines in a dose- and time-dependent manner through ROS induction. Meanwhile, an intrinsic caspase-dependent apoptosis pathway was observed in the TC cells under PL treatment. The activation of Erk and the suppression of the Akt/mTOR pathways through ROS induction were seen in cells treated with PL. PL-mediated apoptosis in TC cells was through the ROS-Akt pathway. Finally, the anticancer effect and safety of PL were also demonstrated in vivo. Our findings indicate that PL exhibits antitumor activity and has the potential for use as a chemotherapeutic agent against TC. This is the first study to show the sensitivity of TC cell lines to PL.

Graphene oxide aerogel assembled by dimethylaminopropylamine /N-isopropylethylenediamine for the removal of copper ions.

Graphene Oxide Monolith composites (GOMs) were prepared using dimethylaminopropylamine (DMPDA) and N-isopropylethylenediamine (IPEDA) with one-step method in water medium, respectively. Fourier transform-infrared (FTIR), X-Ray Diffraction (XRD) tests proved the formation of new structure and credible interactions between crosslinkers and GO. Scanning electron microscopy (SEM) showed distinct change of morphology after complexing. Bath adsorption tests suggested that the fast adsorption of copper ions (II) was strongly affected by pH, ionic strength, temperature, and concentration, etc.. Isothermal Langmuir and Freundlich kinetic model showed the different degree of fitting conformity according to different conditions. SEM and XRD further provided a supporter of adsorption of copper ions onto GOMs, and Density functional theory (DFT) was used to analyze the crosslinking details of DMPDA and GO and the adsorption mechanism of copper ions. The theoretical calculation results clarified an efficacious and quantitative understanding for the crosslinking and adsorption mechanism.

LncRNA HAND2-AS1 inhibits proliferation and promotes apoptosis of non-small cell lung cancer cells by inactivating PI3K/Akt pathway.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a major subtype of lung cancer and is correlated with high incidence and mortality rate. Functionality of lncRNA HAND2-AS1 is only reported in endometrioid endometrial carcinoma and osteosarcoma. In our study, the role of HAND2-AS1 in NSCLC was investigated. METHODS: We first detected the expression of HAND2-AS1 in lung tissues and serum of both NSCLC patients and healthy controls by qRT-PCR. Correlation between HAND2-AS1 expression level and clinical data of NSCLC patients was analyzed by Chi-square test. NSCLC cells, and cell proliferation, cell apoptosis and expression of PI3K/Akt pathway-related proteins were detected by CCK-8 assay, cell apoptosis assay and Western blot, respectively. RESULTS: HAND2-AS1 expression was significantly down-regulated in NSCLC. HAND2-AS1 and tumor size of NSCLC patients were closely associated. Serum HAND2-AS1 can be used to effectively distinguish osteosarcoma patients from healthy controls, and it can also be used to predict prognosis of osteosarcoma patients. HAND2-AS1 overexpression inhibited osteosarcoma cell proliferation, promoted cell apoptosis, and down-regulated phosphorylation of PI3K/Akt pathway-related proteins. PI3K/Akt pathway inhibitor showed no significant effects on HAND2-AS1 expression, but reduced its effects on cell proliferation and apoptosis. CONCLUSION: We conclude that HAND2-AS1 may suppress the proliferation of NSCLC cells by targeting PI3K/Akt pathway.

Berberine Derivatives Suppress Cellular Proliferation and Tumorigenesis In Vitro in Human Non-Small-Cell Lung Cancer Cells.

Lung cancer is the leading cause of death in the world, and the most common type of lung cancer is non-small-cell lung cancer (NSCLC), accounting for 85% of lung cancer. Patients with NSCLC, when detected, are mostly in a metastatic stage, and over half of patients diagnosed with NSCLC die within one year after diagnosis; the 5-year survival rate is 24%. However, in patients with metastatic NSCLC, the 5-year survival rate is 6%. Therefore, development of a new therapeutic agent or strategy is urgent for NSCLCs. Berberine has been illustrated to be a therapeutic agent of NSCLC. In the present study, we synthesized six derivatives of berberine, and the anti-NSCLC activity of these agents was examined. Some of them exert increasing proliferation inhibition comparing with berberine. Further studies demonstrated that two of the most effective agents, 9-O-decylberberrubine bromide (B6) and 9-O-dodecylberberrubine bromide (B7), performed cell cycle regulation, in-vitro tumorigenesis inhibition and autophagic flux blocking, but not induction of cellular apoptosis in NSCLC cells. Moreover, B6 and B7 were determined to be green fluorescent and could be penetrated and localized in cellular mitochondria. Herein, B6 and B7, the berberine derivatives we synthesized, revealed better anti-NSCLC activity with berberine and may be used as therapeutic candidates for the treatment of NSCLCs.

Corrosion resistance of itaconic acid doped polyaniline /nanographene oxide composite coating.

Graphene oxide (GO) and polyaniline (PANI) are very unique materials with broad potential in corrosion protection coating. To achieve the maximum stability and anti-corrosion effect in a polar medium, firstly itaconic acid doped PANI (DP) was readily prepared by a one-step method, followed by forming a GO and DP composite (GODP). Characterization by Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectra provides evidence for the successful doping of itaconic acid in PANI. X-ray diffraction analysis shows that the d-spacing of the GO sheets increases slightly with the intercalation of DP. The morphological studies show disordered structures in GODP compared with the original GO sheets due to the introduction of PANI molecules and the interaction of functional groups on the surface of the GO sheets. Thermogravimetric analysis reveals the good thermal stability of DP and GODP. Quantum calculation further confirms the successful doping of itaconic acid, and the effective complex of GO and DP, providing a quantitative understanding of the curing mechanism. The crosslinking interaction among the GODP, curing agent, and epoxy resin facilitates the formation of a compact coating, leading to excellent corrosion resistance toward Mg alloy.

Honokiol Is a Potential Therapeutic Agent and Has a Synergistic Effect With 5-FU in Human Urothelial Cell Carcinoma Cells.

BACKGROUND/AIM: Honokiol is a biphenolic component of the bark of Magnolia, and has been shown to exert several activities, including anti-depressant, anti-emetic, anti-oxidative, anti-thrombotic, anti-angiogenesis, anti-anxiolytic, anti-inflammatory and anti-tumor effects. MATERIALS AND METHODS: The anti-tumor activities of honokiol and its synergistic effect with 5-fluorouracil (5-FU) in human urothelial cell carcinoma (UCC) cells were investigated. RESULTS: Honokiol significantly suppressed the proliferation of UCC cells in a dose- and time-dependent manner. Moreover, honokiol inhibited the tumorigenesis of UCC cells in vitro. In addition, honokiol induced cell cycle arrest at G0/G1 phase and caused apoptosis of UCC cells through the intrinsic pathway. Importantly, we demonstrated that honokiol potentiated the cytotoxic effect of 5-FU, and displayed a synergistic effect with 5-FU in UCC cells. CONCLUSION: Honokiol causes growth inhibition, tumorigenesis suppression, cell cycle arrest, apoptosis, and importantly has a synergistic effect with 5-FU in human UCC cells. Therefore, this agent displays a therapeutic potential for treating human UCC.

Azobenzene-bridged diradical janus nucleobases with photo-converted magnetic properties between antiferromagnetic and ferromagnetic couplings.

We computationally design a series of azobenzene (AB)-bridged double radicalized nucleobases, a novel kind of diradical Janus-type nucleobases, and explore their spin coupling characteristics. Calculations prove that such diradical Janus-bases not only normally match with their complementary bases, but also exhibit well-defined diradical character with photo-convertible intramolecular magnetic couplings (antiferromagnetic vs. ferromagnetic). Combination of four radical nucleobases (rG, rA, rC, rT) and photoswitch AB can yield 10 diradical Janus-bases with different magnetic characteristics in which AB functions a bridge to mediate the spin coupling between two radical bases. The trans-form supports mild antiferromagnetic couplings with the spin coupling constants (J) ranging from -153.6 cm-1 to -50.91 cm-1 while the cis-form has weak magnetic couplings with ferromagnetic (0.22-8.50 cm-1 ) for most of them or antiferromagnetic (-0.77, -1.73, -3.30 cm-1 ) properties for only three. Further structural examination and frontier molecular orbital analyses indicate that the extended π conjugation for better spin polarization provides an effective through-π-bond pathway to mediate the spin coupling in the trans conformation while nonplanarity of the cis conformation weakens the through-bond coupling and causes a competitive through-space pathway and as an overall result inhibits the spin coupling between two spin moieties. Meanwhile, we also find that the J values of the cis conformation vary with their angle between the radical base and its linked phenylene. Furthermore, the magnetic properties of the diradical Janus-bases can be significantly increased by interacting with metal ions. They also maintain a good UV absorption characteristics and there is a clear redshift compared with AB. This work provides a promising strategy for the rational design of photo-convertible Janus-base magnets as the magnetism-tunable DNA building blocks. © 2018 Wiley Periodicals, Inc.

Remarkable Differences in Spin Couplings for Various Self-Paired Dimers of Ring-Expansion-Radicalized Uracil: A Basis for the Design of Magnetically Anisotropic Assemblies.

The spin-coupling properties of a series of radicalized uracil (rU) dimer diradicals with different H-bonding modes is examined. Each rU has four double H-bonding sites [the amide units: two at the Watson-Crick face (upper site WC1 and lower site WC2 ), a Hoogsteen site (HO), and a minor-groove site (MI)], and ten homogeneous dimers (rU-rU) can self-pair with well-defined diradical characters and comparable stability to the native U dimers. More interestingly, all these dimers exhibit distinctly different spin-coupling characters (ferromagnetic (FM) versus antiferromagnetic (AFM) and large- versus small-magnitude spin couplings), indicative of remarkable magnetic-coupling anisotropy of rU. This observation originates from the fusion of a cyclopentadienyl radical to U, which leads to uneven spin-density distribution. In rU, the fused five-membered radical ring can spin-polarize to the edge in the minor groove, and thus dimerization of rU leads to different H-bonded structures with remarkably different magnetic couplings. The calculated larger magnetic coupling constants J are 1003.7 and 540.2 cm-1 for the WC2 -HO and MI-HO H-bonding modes between rU, which exhibit considerably large FM couplings, the MI-MI, WC1 -WC2 and WC2 -WC2 modes show moderate FM couplings (J=0.4-77 cm-1 ), and the other modes exhibit moderate or weak AFM couplings. These observations indicate that the HO and MI sites are favorable spin-coupling sites. In addition, the H-bond lengths and electronic structures of the H-bonding sites, proton transfer, and extra H-bonding interaction with the surroundings can also affect the magnetic couplings of the base pairs. Clearly, the unique magnetic coupling anisotropy of rU provides a promising application basis for the design and assembly of bio-inspired anisotropically magnetic membranes and even magnetism-tunable building blocks for novel magnetic nanoscale devices.

Gene Expression and DNA Methylation Status of Glutathione S-Transferase Mu1 and Mu5 in Urothelial Carcinoma.

Bladder cancer is highly recurrent after therapy, which has an enormous impact on the health and financial condition of the patient. It is worth developing diagnostic tools for bladder cancer. In our previous study, we found that the bladder carcinogen BBN increased urothelial global DNA CpG methylation and decreased GSTM1 protein expression in mice. Here, the correlation of BBN-decreased GSTM1 and GSTM gene CpG methylation status was analyzed in mice bladders. BBN treatment decreased the protein and mRNA expression of GSTM1, and the CpG methylation ratio of GSTM1 gene promoter was slightly increased in mice bladders. Unlike mouse GSTM1, the human GSTM1 gene tends to be deleted in bladder cancers. Among 7 human bladder cancer cell lines, GSTM1 gene is really null in 6 cell lines except one, T24 cells. The CpG methylation level of GSTM1 was 9.9% and 5-aza-dC did not significantly increase GSTM1 protein and mRNA expression in T24 cells; however, the GSTM5 gene was CpG hypermethylated (65.4%) and 5-aza-dC also did not affect the methylation ratio and mRNA expression. However, in other cell lines without GSTM1, 5-aza-dC increased GSTM5 expression and decreased its CpG DNA methylation ratio from 84.6% to 61.5% in 5637, and from 97.4% to 75% in J82 cells. In summary, two biomarkers of bladder tumor were provided. One is the GSTM1 gene which is down-regulated in mice bladder carcinogenesis and is usually deleted in human urothelial carcinoma, while the other is the GSTM5 gene, which is inactivated by DNA CpG methylation.