Synthesis and Antibacterial Activity of Novel Triazolo[4,3-a]pyrazine Derivatives.

Infectious diseases pose a major challenge to human health, and there is an urgent need to develop new antimicrobial agents with excellent antibacterial activity. A series of novel triazolo[4,3-a]pyrazine derivatives were synthesized and their structures were characterized using various techniques, such as melting point, 1H and 13C nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. All the synthesized compounds were evaluated for in vitro antibacterial activity using the microbroth dilution method. Among all the tested compounds, some showed moderate to good antibacterial activities against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli strains. In particular, compound 2e exhibited superior antibacterial activities (MICs: 32 µg/mL against Staphylococcus aureus and 16 µg/mL against Escherichia coli), which was comparable to the first-line antibacterial agent ampicillin. In addition, the structure-activity relationship of the triazolo[4,3-a]pyrazine derivatives was preliminarily investigated.

Sensitization of cancer cells to radiation by selenadiazole derivatives by regulation of ROS-mediated DNA damage and ERK and AKT pathways.

X-ray-based radiotherapy represents one of the most effective ways in treating human cancers. However, radioresistance and side effect remain as the most challenging issue. This study describes the design and application of novel selenadiazole derivatives as radiotherapy sensitizers to enhance X-ray-induced inhibitory effects on A375 human melanoma and Hela human cervical carcinoma cells. The results showed that, pretreatment of the cells with selenadiazole derivatives dramatically enhance X-ray-induced growth inhibition and colony formation. Flow cytometry analysis indicates that the sensitization by selenadiazole derivatives was mainly caused by induction of G2/M cell cycle arrest. Results of Western blotting demonstrated that the combined treatment-induced A375 cells growth inhibition was achieved by triggering reactive oxygen species-mediated DNA damage involving inactivation of AKT and MAPKs. Further investigation revealed that selenadiazole derivative in combination with X-ray could synergistically inhibit the activity of thioredoxin reductase-1 in A375 cells. Taken together, these results suggest that selenadiazole derivatives can act as novel radiosensitizer with potential application in combating human cancers.

Atomic force microscopy of chronic lymphatic leukaemia cells activation induced by Staphylococcus aureus.

Activation of lymphatic cells is associated with changes in morphology, ultrastructure and adhesion force. We have investigated the activation efficiency of Staphylococcus aureus (SAC) on B-cell chronic lymphatic leukaemia (B-CLL) cells using atomic force microscopy (AFM), and found changes in the above properties. Cell viability and proliferation were measured using Cell Counting Kit-8 (CCK-8) and enzyme-linked immunosorbent assay (ELISA). AFM clearly showed that the volume and nuclear-cytoplasm ratio of cells increased significantly with activated time. It also showed that pseudopodia and immunological synapses began to appear at 24 h. In the activation process, nano-structures of the cell surface became aggregated, and adhesion increased. In conclusion, the results indicate a close relationship between membrane reconstruction and multiplication process of B-CLL cells.

Synthesis of nitrogen mustard-based fluorophores for cell imaging and cytotoxicity studies.

Nitrogen mustards are important alkylating anticancer drugs used for neoplasms treatment. However, little research about the integration of luminophore into nitrogen mustard-based compounds for both imaging and therapeutic application was reported. In this study, we report a series of novel nitrogen mustard-containing 1-furyl-2-en-1-one and 1-thienyl-2-en-1-one derivatives as intramolecular charge transfer-based luminophore for research in both imaging subcellular localization and antiproliferation toward lung cancer cells. The target products were prepared by Knoevenagel condensation and characterized by nuclear magnetic resonance and high-resolution mass spectrometer. The absorption and fluorescence studies were carried out by ultraviolet-visible and fluorescence spectrophotometers, respectively. Cell morphology was observed under an inverted microscope. Cytotoxicity test was detected by MTT assay. Cellular localization was observed by a confocal laser scanning microscope. Colony formation ability was carried out by colony formation assay. Cell migration ability was detected by transwell migration assay. Differences between the two groups were analyzed by two-tailed Student's t-test. The difference with P < 0.05 (*) was considered statistically significant. The compounds were synthesized in high yield. The λmax and Stokes shift of these compounds reach up to 567 and 150 nm, respectively. These compounds exhibited good antiproliferative activity against lung cancer cells, with compound 3h exhibiting the best IC50 of 13.1 ± 2.7 µM. Furthermore, the selected compound 3h is located preferentially in lysosomes and a small amount in nuclei, effectively inhibiting cell colony formation and migration abilities toward A549 cells. These findings suggested that nitrogen mustard-based fluorophores might be a potential effective chemotherapeutic agent in lung cancer therapy.

[Study of dental arch width in patients with idiopathic condylar resorption].

Objective:To investigate the relationship between idiopathic condylar resorption （ICR） and arch width disorder. Methods:Thirty-two patients with ICR and twenty patients without condylar resorption were enrolled according to the same inclusion criteria. They were divided into experimental group and control group. The experimental group was divided into unilateral ICR group and bilateral ICR group according to the affected side of condylar resorption, and then experimental group was divided into subgroups ICR Ⅰ, ICRⅡand ICR Ⅲ according to the degree of condylar resorption. Patients with no condylar resorption were used as a control group. The width of anterior, middle and posterior segments of dental arch on cone beam computed tomography（CBCT） was measured and the two groups of measured values were statistically analyzed. Results:Compared with the control group, the width of maxillary anterior, middle and posterior segments in ICR group was significantly reduced, and the difference was statistically significant（P<0.01）. But the width of mandibular segment was not significantly different from that in control group（P>0.05）. There was no significant difference in the width of anterior, middle and posterior dental arch between subgroups（P>0.05）. Conclusion:Almost all patients with ICR have malocclusion of maxillary and mandibular arch width, but there is no significant correlation between the malocclusion width and the severity of condylar resorption.

New pentahydroxylated steroids from the South China Sea gorgonian Subergorgia suberosa.

Two new pentahydroxylated steroids, (3ß,12ß,16ß,23E)-cholesta-5,23-diene-3,12,16,20,25-pentaol (1) and (3ß,12ß,16ß)-cholesta-5,25(26)-diene-3,12,16,20,24-pentaol (2), were isolated from the EtOH extract of the South China Sea gorgonian Subergorgia suberosa. In addition, four known steroids were detected. The structures of these compounds were established by spectroscopic methods and comparison of their data with those of the related known compounds. In addition, the cyctotoxicities of the compounds were evaluated against selected cancer cell lines.

2-Carbamoyl-3,4,5,6-tetra-fluoro-benzoic acid.

In the title compound, C(8)H(3)F(4)NO(3), the carb-oxy group lies nearly in the plane of the ring with a C-C-C-O torsion angle of -10.5 (4)°. The carbamoyl group is almost perpendic-ular to the benzene ring [C-C-C-O torsion angle = 82.2 (4) °]. In the crystal, molecules are linked via O-H⋯O and N-H⋯O hydrogen bonds involving the carbamoyl and carb-oxy groups.

Protective effects of curcumin/cyclodextrin polymer inclusion complex against hydrogen peroxide-induced LO2 cells damage.

The objective of the present study was to explore the protective effects of the curcumin/cyclodextrin polymer (CUR/CDP) inclusion complex on hydrogen peroxide (H2O2)-induced LO2 cells damage. In this study, a H2O2-induced cells oxidative injury model was established to test the protective effects of the CUR/CDP inclusion complex. The cell viability of cells was detected by the thiazolyl blue tetrazolium bromide (MTT) assay. The extracellular lactate dehydrogenase (LDH) activity, catalase (CAT) activity, and malondialdehyde (MDA) level were detected by assay kits. The cellular reactive oxygen species (ROS) level was detected using the dichlorodihydrofluorescein (DCF) fluorescence assay. Western blotting analysis was conducted to assess the changes of phosphorylated-p53 and caspase-3. The results showed that 700 µM H2O2-treated LO2 cells for 3 h resulted in a significant decrease of cell viability to 53.00 ± 1.68%, which established the cell oxidative injury model. Cells treated with H2O2 led to a significant increase of extracellular LDH activity, MDA content, and ROS level, and decreased CAT activity. Treatment with CUR/CDP significantly reversed the changes of the above indicators. Moreover, CUR/CDP treatment at 20 and 40 µg/ml inhibited H2O2-induced increase in phosphorylated-p53 and caspase-3 expression, indicating that CUR/CDP suppressed cell apoptosis to alleviate liver injury. The results of those studies demonstrated that CUR/CDP had a protective effect on the oxidative damage of LO2 cells, and it could be developed as a new type of natural liver protection product to apply in the prevention of liver injury.

[Study on the secondary metabolites from the marine sponge Phakellia fusca fungi PF18].

OBJECTIVE: To study the secondary metabolites from the marine sponge Phakellia fusca epiphytic fungi. METHODS: The compounds were isolated by column chromatography over silica gel and purified by Sephadex LH-20 column chromatography and preparative TLC. The structures were elucidated by means of physiochemical properties and spectroscopic analyses. RESULTS: Four compounds were separated and identified as: cyclo-(L-Val-L-Pro) (1), cyclo-(L-Phe-L-Pro) (2), cyclo-(L-Tyr-L-Pro) (3), cyclo-(3-hydroxy-4-methyldecanoyl-Gly-L-Val-D-Leu-L-Ala-L-Phe) (4). CONCLUSION: Compounds 1-4 are obtained from the marine sponge Phakellia fusca epiphytic fungi for the first time.

Designing Dihydrofolate Reductase Inhibitors as X-ray Radiosensitizers to Reverse Radioresistance of Cervical Cancer.

X-ray radiotherapy has been widely used in the treatment of cervical cancer, a common gynecologic malignant tumor. However, the therapeutic efficacy tends to be indistinctive. One major reason for this is amplification of the dihydrofolate reductase (DHFR) gene, which causes an increase in DHFR activity and attenuation of the treatment effect. To solve this problem, we synthesized a series of DHFR inhibitors derived from methotrexate (MTX) analogues as radiotherapy sensitizers. Activity screening revealed that compound 2a exerted the best inhibitory effect toward DHFR activity. In combination with X-ray radiotherapy (4 Gy), 2a showed much more prominent antiproliferative activity on cervical cancer cells than 2a or X-rays alone and revealed higher selectivity and radiosensitization than MTX. In vitro experiments showed that 2a + X-rays significantly induced cell apoptosis, as revealed by the increase in the Sub-G1 population and activation of caspase 3, 8, and 9. The in vivo antitumor effect demonstrated that in the presence of X-rays, 2a effectively suppressed tumor growth and did not cause obvious side effects. In conclusion, as a DHFR inhibitor, 2a successfully reversed the radioresistance problem induced by radiotherapy and greatly promoted the therapeutic effect. This is a promising candidate for tumor treatment that deserves further research and development. This study clearly demonstrates that DHFR inhibitors could be developed as promising radiosensitizers in the treatment of cervical cancer and that further research to improve their activity and potential in future clinical use is deserved.

Therapeutic nanosystems co-deliver anticancer drugs and oncogene SiRNA to achieve synergetic precise cancer chemo-gene therapy.

Co-delivering a chemotherapeutic agent and cancer-specific small interfering RNA (siRNA) as a new therapeutic modality provides a promising strategy for cancer treatment. In this study, we designed and described a cancer-target and pH-sensitivity nanosystem (RGD-SeNPs/siRNA) which has a DOX-loaded SeNPs core and c-myc siRNA-delivered PAMAM-RGD decoration for combination therapy against glioblastoma. The nanosystem exhibited high stability in water and FBS solutions for a long time. PAMAM-RGD surface decoration significantly enhanced the cellular uptake of RGD-SeNPs/siRNA and increased the selectivity between normal and cancer cells. More importantly, the nanosystem expanded to petaloid particles under pH 5.3 circumstance, which prolonged the duration of drugs after ingestion and reduced undesirable side effects. In addition, a blood-brain barrier (BBB) model we established in vitro revealed the nanosystem effectively penetrated BBB and enhanced antitumor activity. Moreover, the nanosystem also exhibited excellent advantages in penetrating ability and inhibitory effects on U251 tumor spheroids, demonstrating its in vivo anticancer potential. Therefore, this study provides a strategy for the design of cancer-targeted nanoplatforms as carriers of oncogene siRNA and chemotherapeutics to achieve synergistic cancer therapy.

Cancer-targeted design of bioresponsive prodrug with enhanced cellular uptake to achieve precise cancer therapy.

Chemical drug design based on the biochemical characteristics of cancer cells has become an important strategy for discovery of novel anticancer drugs to enhance the cancer targeting effects and biocompatibility, and decrease toxic side effects. Camptothecin (CPT) demonstrated strong anticancer activity in clinical trials but also notorious adverse effects. In this study, we presented a smart targeted delivery system (Biotin-ss-CPT) that consists of cancer-targeted moiety (biotin), a cleavable disulfide linker (S-S bond) and the active drug CPT. Biotin-ss-CPT was found to exhibit potent effects on the migration of cancer cells and induced apoptosis by induction of ROS-mediated mitochondrial dysfunction and perturbation of GSH/GPXs system, as well as activation of caspases. In vivo tumor suppression investigation including toxicity evaluation and pathology analysis, accompanied by MR images showed that Biotin-ss-CPT can be recognized specifically and selectively and taken up preferentially by cancers cells, followed by localization and accumulation effectively in tumor site, then released CPT by biological response to achieve high therapeutic effect and remarkably reduced the side effects that free CPT caused, such as liver damage, renal injury, and weight loss to realize precise cancer therapy. Taken together, our results suggest that biotinylation and bioresponsive functionalization of anticancer drugs could be a good way for the discovery of next-generation cancer therapeutics.

Microwave-Assisted Syntheses of Benzimidazole-Containing Selenadiazole Derivatives That Induce Cell-Cycle Arrest and Apoptosis in Human Breast Cancer Cells by Activation of the ROS/AKT Pathway.

The use of selenium-containing heterocyclic compounds as potent cancer chemopreventive and chemotherapeutic agents has been well documented by a large number of clinical studies. In this study we developed a new approach to synthesize four benzimidazole-containing selenadiazole derivatives (BSeDs). The method uses a combination of peptide coupling reagents and microwave irradiation. This strategy features milder reaction conditions, higher yields, and shorter reaction times. The synthetic BSeDs were identified as potent antiproliferative agents against the human MCF-7 and MDA-MB-231 breast cancer cell lines. Compounds 1 b (5-(6-methyl-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]selenadiazole), 1 c (5-(6-chloro-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]selenadiazole), and 1 d (5-(6-bromo-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]selenadiazole) were found to show greater cytotoxicity against the triple-negative breast cancer cell line MDA-MB-231 than MCF-7, and to exhibit dose-dependent inhibition of cell migration, in which a significant decrease in the zone of cell monolayer wound closure was observed relative to untreated controls. Our results demonstrate that BSeDs can cause cell-cycle arrest and apoptosis in MDA-MB-231 cells by inducing DNA damage, inhibiting protein kinase B (AKT), and activating mitogen-activated protein kinase (MAPK) family members through the overproduction of reactive oxygen species (ROS). Taken together, the results of this study provide a facile microwave-assisted strategy for the synthesis of selenium-containing organic compounds that exhibit a high level of anticancer efficacy.

Selenadiazole derivatives as potent thioredoxin reductase inhibitors that enhance the radiosensitivity of cancer cells.

Thioredoxin system is an attractive target to overcome radioresistance in cancer therapy. The redox enzyme thioredoxin reductase (TrxR) plays a vital role in restoring cellular thiol redox balance disrupted by radiation-induced reactive oxygens species (ROS) generation and oxidative damage. In this study, a series of 1,2,5-selenadiazoles have been synthesized and identified as highly effective inhibitors of TrxR to disrupt the intracellular redox balance, and thus significantly enhanced the sensitivity of cancer cells to X-ray. Upon irradiation, 1,2,5-selenadiazoles displayed a marked synergistic inhibitory effect on radioresistant A375 melanoma cell through enhancement of ROS overproduction, and subsequent induction of ROS-promoted apoptotic pathways, which triggered then mitochondrial dysfunction and caspase activation, finally resulted in augment of radiotherapeutic efficacy. Interestingly, we also found the interaction sites between 1,2,5-selenadiazole and the model peptide of TrxR, which can be confirmed by MALDI-ToF-MS. These results clearly demonstrate TrxR as a potential target for therapy of radioresistant cancers, and selenadiazole derivatives may be attractive radiosensitizing agent by targeting TrxR.

Strategy to enhance the anticancer efficacy of X-ray radiotherapy in melanoma cells by platinum complexes, the role of ROS-mediated signaling pathways.

Radiotherapy plays an important role in treatment of cancers with low toxicity to the surrounding normal tissues. However, it still fails to eradicate hypoxic tumors due to the occurrence of radioresistance. Therefore, the search for new radiation sensitizers is of great significance. Platinum (Pt) complexes have been identified as potential radiation sensitizers to increase the sensitivity of cancer cells to radiotherapy. In the present study, we have synthesized four Pt complexes containing (2 - benzimidazole [4, 5-f] - [1, 10] phenanthroline) ligand and found that they could effectively enhance the X-ray-induced growth inhibition against A375 human melanoma cells through induction of G2/M cell cycle arrest. In contrast, they showed much lower cytotoxicity toward human normal cells. The complexes also dramatically inhibited the TrxR activity and caused intracellular ROS overproduction, due to the Auger electron effect of heavy metal element under X-ray radiation. Excessive ROS triggered DNA damage and activated downstream signaling pathways, including the phosphorylation of p53 and p38MAPK, and down-regulation of phosphorylated AKT and ERK, finally resulted in increase of radiosensitivity and inhibition of tumor reproduction. Taken together, our results suggest that the synthetic Pt complexes could be further developed as sensitizers of X-ray radiotherapy.

Cyanidin reverses cisplatin-induced apoptosis in HK-2 proximal tubular cells through inhibition of ROS-mediated DNA damage and modulation of the ERK and AKT pathways.

Cyanidin is an anthocyanin widely distributed in food diet with novel antioxidant activity. Herein, we investigated the protective effects of cyanidin on HK-2 proximal tubular cells against cisplatin-induced apoptosis and elucidated the underlying mechanisms. The results showed that cisplatin-induced apoptosis in HK-2 cells was significantly attenuated by cyanidin. The cleavage of caspases and PARP, activation of p53 and mitochondrial-mediated apoptosis pathways induced by cisplatin were effectively blocked by cyanidin. Moreover, cyanidin significantly suppressed the overproduction of ROS, and activation of ERK and AKT pathways triggered by cisplatin. Our results indicate that cyanidin exhibits therapeutic potential in prevention of cisplatin-induced nephrotoxicity.