Curcumin induces apoptotic cell death and protective autophagy by inhibiting AKT/mTOR/p70S6K pathway in human ovarian cancer cells.

PURPOSE: Curcumin (Cur), a yellow-colored dietary flavor from the plant (Curcuma longa), has been demonstrated to potentially resist diverse diseases, including ovarian cancer, but drug resistance becomes a major limitation of its success clinically. The key molecule or mechanism associated with curcumin resistance in ovarian cancer still remains unclear. The aim of our study was to investigate the effects of curcumin on autophagy in ovarian cancer cells and elucidate the underlying mechanism. METHODS: In our study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), EdU proliferation assay and colony-forming assay were used to assess cell viability. Apoptosis was detected by western blot and flow cytometric analysis of apoptosis. Autophagy was defined by both electron microscopy and immunofluorescence staining markers such as microtubule-associated protein 1 light chain 3 (LC3). Plasmid construction and shRNA transfection helped us to confirm the function of curcumin. RESULTS: Curcumin reduced cell viability and induced apoptotic cell death by MTT assay in human ovarian cancer cell lines SK-OV-3 and A2780 significantly. Electron microscopy, western blot and immunofluorescence staining proved that curcumin could induce protective autophagy. Moreover, treatment with autophagy-specific inhibitors or stable knockdown of LC3B by shRNA could markedly enhance curcumin-induced apoptosis. Finally, the cells transiently transfected with AKT1 overexpression plasmid demonstrated that autophagy had a direct relationship with the AKT/mTOR/p70S6K pathway. CONCLUSIONS: Curcumin can induce protective autophagy of human ovarian cancer cells by inhibiting the AKT/mTOR/p70S6K pathway, indicating the synergistic effects of curcumin and autophagy inhibition as a possible strategy to overcome the limits of current therapies in the eradication of epithelial ovarian cancer.

Dengue virus envelope domain III immunization elicits predominantly cross-reactive, poorly neutralizing antibodies localized to the AB loop: implications for dengue vaccine design.

Dengue virus (DENV) is a mosquito-borne virus that causes severe health problems. An effective tetravalent dengue vaccine candidate that can provide life-long protection simultaneously against all four DENV serotypes is highly anticipated. A better understanding of the antibody response to DENV envelope protein domain III (EDIII) may offer insights into vaccine development. Here, we identified 25 DENV cross-reactive mAbs from immunization with Pichia pastoris-expressed EDIII of a single or all four serotype(s) using a prime-boost protocol, and through pepscan analysis found that 60 % of them (15/25) specifically recognized the same highly conserved linear epitope aa 309-320 of EDIII. All 15 complex-reactive mAbs exhibited significant cross-reactivity with recombinant EDIII from all DENV serotypes and also with C6/36 cells infected with DENV-1, -2, -3 and -4. However, neutralization assays indicated that the majority of these 15 mAbs were either moderately or weakly neutralizing. Through further epitope mapping by yeast surface display, two residues in the AB loop, Q316 and H317, were discovered to be critical. Three-dimensional modelling analysis suggests that this epitope is surface exposed on EDIII but less accessible on the surface of the E protein dimer and trimer, especially on the surface of the mature virion. It is concluded that EDIII as an immunogen may elicit cross-reactive mAbs toward an epitope that is not exposed on the virion surface, therefore contributing inefficiently to the mAbs neutralization potency. Therefore, the prime-boost strategy of EDIII from a single serotype or four serotypes mainly elicited a poorly neutralizing, cross-reactive antibody response to the conserved AB loop of EDIII.

Evaluation and analysis of dengue virus enhancing and neutralizing activities using simple high-throughput assays.

The risk of antibody-dependent enhancement (ADE) of dengue virus (DENV) infection is a major obstacle for the development of dengue vaccine candidates. Here, we described a novel approach for assessment of ADE by measuring DENV nonstructural protein 1 (NS1) production in culture supernatants with Fcγ receptor-expressing K562 cells in ELISA format (ELISA-ADE). Enhancing activities quantified by measurement of kinetics of NS1 production were in a good agreement with the results of the virus titration assay. In conjunction with the previously established enzyme-linked immunospot-based micro-neutralization test (ELISPOT-MNT) in 96-well format, the observable dose-response profiles of enhancing and neutralizing activities against all four DENV serotypes were produced with two flaviviral envelope cross-reactive monoclonal antibodies and four primary DENV-1-infected human sera. The simple high-throughput ELISA-ADE assay offers advantages for quantitative measurement of infection enhancement that can potentially be applied to large-scale seroepidemiological studies of DENV infection and vaccination.

Meta-analysis of diffusion-weighted magnetic resonance imaging in detecting prostate cancer.

PURPOSE: The objective of this study was to determine the diagnostic performance of quantitative diffusion-weighted magnetic resonance imaging in detection of prostate cancer. METHODS: A comprehensive search was performed for English articles published before May 2012 that fulfilled the following criteria: patients had histopathologically proved prostate cancer; diffusion-weighted imaging (DWI) was performed for the detection of prostate cancer, and data for calculating sensitivity and specificity were included. Methodological quality was assessed by using the quality assessment of diagnostic studies instrument. Publication bias analysis, homogeneity, inconsistency index, and threshold effect were performed by STATA version 12. RESULTS: Of 119 eligible studies, 12 with 1637 malignant and 4803 benign lesions were included. There was notable heterogeneity beyond threshold effect and publication bias. The sensitivity and specificity with 95% confidence interval (CI) estimates of DWI on a per-lesion basis were 77% (CI, 0.76-0.84) and 84% (CI, 0.78-0.89), respectively, and the area under the curve of summary receiver operating characteristic curve was 0.88 (CI, 0.85-0.90). The overall positive and negative likelihood ratios with 95% CI were 4.93 (3.39-7.17) and 0.278 (0.19-0.39), respectively. CONCLUSIONS: Quantitative DWI has a relative sensitivity and specificity to distinguish malignant from benign in prostate lesions. However, large-scale randomized control trials are necessary to assess its clinical value because of nonuniformed diffusion gradient b factor, diagnosis threshold, and small number of studies.

Isolation and full-length sequence analysis of Armigeres subalbatus totivirus, the first totivirus isolate from mosquitoes representing a proposed novel genus (Artivirus) of the family Totiviridae.

During an investigation of arboviruses in China, a novel dsRNA virus was isolated from adult female Armigeres subalbatus. Full genome sequence analysis showed the virus to be related to members of the family Totiviridae, and was therefore named 'Armigeres subalbatus totivirus' (AsTV). Transmission electron microscopy identified icosahedral, non-enveloped virus particles with a mean diameter of 40 nm. The AsTV genome is 7510 bp in length, with two ORFs. ORF1 (4443 nt) encodes the coat-protein and a dsRNA-binding domain (which may be involved in the evasion of 'gene silencing'), while ORF2 (2286 nt) encodes the viral RNA-dependent RNA polymerase (RdRp). The AsTV coat protein shows a higher level of amino acid identity with Drosophila totivirus (DTV, 52 %) than with infectious myonecrosis virus (IMNV, 29 %). Similarly, the RdRp shows higher identity levels with DTV (51 %) than with IMNV (44 %). Identity levels to other members of the family Totiviridae, in either the coat protein or the RdRp, ranged from 6 to 11 %. Based on a recent reassessment of the coding strategy used by IMNV, we suggest that an AsTV coat-RdRp fusion protein could be synthesized via a -1 frameshift. Elements favouring -1 frameshift such as 'slippery heptamers' and pseudonkots, were identified in the AsTV, DTV and IMNV genomes. AsTV was shown to grow in both mosquito and mammalian cells, suggesting that it is an arbovirus that can infect mammals.

Improvement of graft function and animal survival by fat emulsion in liver transplant rats.

Nutritional supports are required for liver transplant patients. However, no systematical assessment has been made of the optimal composition of energy yielding substrates in these patients. This study is to evaluate whether mixed energy system consisting of carbohydrate and lipid emulsions is more advantageous over single energy source of glucose for nutritional support in liver transplant recipients and whether structured lipid emulsion (STG) is superior to medium-chain triglyceride/long-chain triglycerides (MCT/LCT) and long-chain triglycerides (LCT) using a total parenteral nutrition model. Liver transplant rats were randomly divided to four groups according to the energy source, i.e. glucose (GLU), MCT/LCT, STG and LCT groups. Sham operated rats served as control. Hepatic function and lipid profile were determined to investigate the roles of lipid emulsion in hepatic function and lipid metabolism. Morphological changes of liver were observed, and nitrogen balance was determined. The results showed that infusion of lipid emulsion was well tolerated. The 1-week survival rate in the lipid emulsion groups was significantly higher than in the GLU group (100% versus 50%, P<0.05); compared with the GLU group, hepatic function recovered quickly and returned to normal level, and morphological alterations were less severer in the lipid emulsion groups, especially in the STG group; the lipid emulsions groups had normal serum TG and TC levels, especially STG and MCT/LCT groups; the lipid emulsions groups achieved a positive nitrogen balance on day 7 compared with the GLU group, and the STG group had the highest nitrogen balance. In conclusion, lipid emulsion is beneficial in improving hepatic function and the recipients' survival and does not influence the lipid metabolism. Mixed energy system consisting of carbohydrate and lipid is more advantageous over single energy source of glucose after liver transplantation, and STG is superior to MCT/LCT and LCT.

The diagnostic value of 1.5-T diffusion-weighted MR imaging in detecting 5 to 10 mm metastatic cervical lymph nodes of nasopharyngeal carcinoma.

The aim of the study was to prospectively assess the diagnostic accuracy of 1.5 T diffusion-weighted imaging (DWI) for 5 to 10 mm metastatic cervical lymph nodes of patients with nasopharyngeal carcinoma (NPC). All patients with histopathologically confirmed NPC underwent DWI with 2 b values of 0 and 800 s/mm were enrolled. The shortest axial diameter and mean apparent diffusion coefficient (ADC) value were recorded when lymph nodes with a shortest axial diameter from 5 to 10 mm were measured. The correlation between the pathological diagnoses and mean ADC values in the benign and metastatic lymph nodes were compared using the Z test. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of DWI. Three hundred fourteen nodes of 52 patients with NPC consisted of 46.5% (146/314) metastatic lymph nodes and 53.5% (168/314) benign lymph nodes. The mean ADC value (×10 mm/s) of benign lymph nodes was (1.110 ±â€Š0.202), which was significantly higher than that of metastatic nodes (0.878 ±â€Š0.159) (P < 0.05). The sensitivity, specificity, positive predictive value, and negative predictive value, accuracy for differentiating metastatic from benign lymph nodes using a cutoff ADC value of 0.924 × 10 mm/s was 83.56%, 82.74%, 80.79%, 85.28%, and 82.80%, respectively. The area under the ROC curve was 0.851 (95% confidence intervals: 0.807-0.889). This study demonstrated that DWI is helpful in detecting 5 to 10 mm metastatic lymph nodes of patients with NPC.