PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (5848)
 

Clipboard (0)
None
Journals
more »
Year of Publication
1.  Childhood sexual abuse and the risk for recurrent major depression in Chinese women 
Psychological Medicine  2011;42(2):409-417.
Background
Studies in Western countries have repeatedly shown that women with a history of childhood sexual abuse (CSA) are at increased risk for developing major depression (MD). Would this relationship be found in China?
Method
Three levels of CSA (non-genital, genital, and intercourse) were assessed by self-report in two groups of Han Chinese women: 1970 clinically ascertained with recurrent MD and 2597 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression and regression coefficients by linear or Poisson regression.
Results
Any form of CSA was significantly associated with recurrent MD [OR 3.26, 95% confidence interval (CI) 1.95–5.45]. This association strengthened with increasing CSA severity: non-genital (OR 2.47, 95% CI 1.17–5.23), genital (OR 2.77, 95% CI 1.32–5.83) and intercourse (OR 13.35, 95% CI 1.83–97.42). The association between any form of CSA and MD remained significant after accounting for parental history of depression, childhood emotional neglect (CEN), childhood physical abuse (CPA) and parent–child relationship. Among the depressed women, those with CSA had an earlier age of onset, longer depressive episodes and an increased risk for generalized anxiety disorder (GAD; OR 1.92, 95% CI 1.39–2.66) and dysthymia (OR 2.16, 95% CI 1.52–3.09).
Conclusions
In Chinese women CSA is strongly associated with MD and this association increases with greater severity of CSA. Depressed women with CSA have an earlier age of onset, longer depressive episodes and increased co-morbidity with GAD and dysthymia. Although reporting biases cannot be ruled out, our results are consistent with the hypothesis that, as in Western countries, CSA substantially increases the risk for MD in China.
doi:10.1017/S0033291711001462
PMCID: PMC3250087  PMID: 21835095
Childhood sexual abuse; co-morbidity; major depression
2.  Copy Number Variation in CNP267 Region May Be Associated with Hip Bone Size 
PLoS ONE  2011;6(7):e22035.
Osteoporotic hip fracture (HF) is a serious global public health problem associated with high morbidity and mortality. Hip bone size (BS) has been identified as one of key measurable risk factors for HF, independent of bone mineral density (BMD). Hip BS is highly genetically determined, but genetic factors underlying BS variation are still poorly defined. Here, we performed an initial genome-wide copy number variation (CNV) association analysis for hip BS in 1,627 Chinese Han subjects using Affymetrix GeneChip Human Mapping SNP 6.0 Array and a follow-up replicate study in 2,286 unrelated US Caucasians sample. We found that a copy number polymorphism (CNP267) located at chromosome 2q12.2 was significantly associated with hip BS in both initial Chinese and replicate Caucasian samples with p values of 4.73E-03 and 5.66E-03, respectively. An important candidate gene, four and a half LIM domains 2 (FHL2), was detected at the downstream of CNP267, which plays important roles in bone metabolism by binding to several bone formation regulator, such as insulin-like growth factor-binding protein 5 (IGFBP-5) and androgen receptor (AR). Our findings suggest that CNP267 region may be associated with hip BS which might influence the FHL2 gene downstream.
doi:10.1371/journal.pone.0022035
PMCID: PMC3137628  PMID: 21789208
3.  FOXP3 Orchestrates H4K16 Acetylation and H3K4 Tri-Methylation for Activation of Multiple Genes through Recruiting MOF and Causing Displacement of PLU-1 
Molecular cell  2011;44(5):770-784.
SUMMARY
Both H4K16 acetylation and H3K4 tri-methylation are required for gene activation. However, it is still largely unclear how these modifications are orchestrated by transcriptional factors. Here we analyzed the mechanism of the transcriptional activation by FOXP3, an X-linked suppressor of autoimmune diseases and cancers. FOXP3 binds near transcriptional start sites of its target genes. By recruiting MOF and displacing histone H3K4 demethylase PLU-1, FOXP3 increases both H4K16 acetylation and H3K4 tri-methylation at the FOXP3-associated chromatins of multiple FOXP3-activated genes. RNAi-mediated silencing of MOF reduced both gene activation and tumor suppression by FOXP3, while both somatic mutations in clinical cancer samples and targeted mutation of FOXP3 in mouse prostate epithelial disrupted nuclear localization of MOF. Our data demonstrate a pull-push model in which a single transcription factor orchestrates two epigenetic alterations necessary for gene activation and provide a mechanism for somatic inactivation of the FOXP3 protein function in cancer cells.
doi:10.1016/j.molcel.2011.10.012
PMCID: PMC3243051  PMID: 22152480
4.  A comparison of ARMS and direct sequencing for EGFR mutation analysis and Tyrosine Kinase Inhibitors treatment prediction in body fluid samples of Non-Small-Cell Lung Cancer patients 
Background
Epidermal growth factor receptor (EGFR) mutation is strongly associated with the therapeutic effect of tyrosine kinase inhibitors (TKIs) in patients with non-small-cell lung cancer (NSCLC). Nevertheless, tumor tissue that needed for mutation analysis is frequently unavailable. Body fluid was considered to be a feasible substitute for the analysis, but arising problems in clinical practice such as relatively lower mutation rate and poor clinical correlation are not yet fully resolved.
Method
In this study, 50 patients (32 pleural fluids and 18 plasmas) with TKIs therapy experience and with direct sequencing results were selected from 220 patients for further analysis. The EGFR mutation status was re-evaluated by Amplification Refractory Mutation System (ARMS), and the clinical outcomes of TKIs were analyzed retrospectively.
Results
As compared with direct sequencing, 16 positive and 23 negative patients were confirmed by ARMS, and the other 11 former negative patients (6 pleural fluids and 5 plasmas) were redefined as positive, with a fairly well clinical outcome (7 PR, 3 SD, and 1 PD). The objective response rate (ORR) of positive patients was significant, 81.3% (direct sequencing) and 72.7% (ARMS) for pleural fluids, and 80% (ARMS) for plasma. Notably, even reclassified by ARMS, the ORR for negative patients was still relatively high, 60% for pleural fluids and 46.2% for plasma.
Conclusions
When using body fluids for EGFR mutation analysis, positive result is consistently a good indicator for TKIs therapy, and the predictive effect was no less than that of tumor tissue, no matter what method was employed. However, even reclassified by ARMS, the correlation between negative results and clinical outcome of TKIs was still unsatisfied. The results indicated that false negative mutation still existed, which may be settled by using method with sensitivity to single DNA molecule or by optimizing the extraction procedure with RNA or CTC to ensure adequate amount of tumor-derived nucleic acid for the test.
doi:10.1186/1756-9966-30-111
PMCID: PMC3287118  PMID: 22142557
Body Fluids; EGFR Mutation; Direct Sequencing; ARMS; TKIs; NSCLC
5.  Association of genetic variation in FTO with risk of obesity and type 2 diabetes with data from 96,551 East and South Asians 
Diabetologia  2011;55(4):981-995.
Aims/hypothesis
FTO harbours the strongest known obesity-susceptibility locus in Europeans. While there is growing evidence for a role for FTO in obesity risk in Asians, its association with type 2 diabetes, independently of BMI, remains inconsistent. To test whether there is an association of the FTO locus with obesity and type 2 diabetes, we conducted a meta-analysis of 32 populations including 96,551 East and South Asians.
Methods
All studies published on the association between FTO-rs9939609 (or proxy [r2 > 0.98]) and BMI, obesity or type 2 diabetes in East or South Asians were invited. Each study group analysed their data according to a standardised analysis plan. Association with type 2 diabetes was also adjusted for BMI. Random-effects meta-analyses were performed to pool all effect sizes.
Results
The FTO-rs9939609 minor allele increased risk of obesity by 1.25-fold/allele (p = 9.0 × 10−19), overweight by 1.13-fold/allele (p = 1.0 × 10−11) and type 2 diabetes by 1.15-fold/allele (p = 5.5 × 10−8). The association with type 2 diabetes was attenuated after adjustment for BMI (OR 1.10-fold/allele, p = 6.6 × 10−5). The FTO-rs9939609 minor allele increased BMI by 0.26 kg/m2 per allele (p = 2.8 × 10−17), WHR by 0.003/allele (p = 1.2 × 10−6), and body fat percentage by 0.31%/allele (p = 0.0005). Associations were similar using dominant models. While the minor allele is less common in East Asians (12–20%) than South Asians (30–33%), the effect of FTO variation on obesity-related traits and type 2 diabetes was similar in the two populations.
Conclusions/interpretation
FTO is associated with increased risk of obesity and type 2 diabetes, with effect sizes similar in East and South Asians and similar to those observed in Europeans. Furthermore, FTO is also associated with type 2 diabetes independently of BMI.
Electronic supplementary material
The online version of this article (doi:10.1007/s00125-011-2370-7) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
doi:10.1007/s00125-011-2370-7
PMCID: PMC3296006  PMID: 22109280
Asians; FTO; Meta-analysis; Obesity; Type 2 diabetes
6.  Evaluation of several adjuvants in avian influenza vaccine to chickens and ducks 
Virology Journal  2011;8:321.
The effects of three different adjuvants, mineral oil, Montanide™ ISA 70M VG, and Montanide™ ISA 206 VG, were evaluated on reverse genetics H5N3 avian influenza virus cell cultured vaccine. The immune results of SPF chickens after challenging with highly pathogenic avian influenza (HPAI) virus demonstrated that mineral oil adjuvant group and 70M adjuvant group provided 100% protection efficiency, but 206 adjuvant group provided only 40%. Statistical analysis indicated that the protection effects of mineral oil adjuvant group and the 70M adjuvant showed no significant difference to each other, but with significant difference to 206 adjuvant group. All three groups could induce high titres of antibody after immunizing SPF ducks, but there was no significant difference among them. The immunization effect of 70M adjuvant group on SPF chickens were the best and showed significant difference compared with optimized 70Mi Montanide™ eight series adjuvants groups. These results suggest that 70M adjuvant could be a novel adjuvant for preparing avian influenza vaccine.
doi:10.1186/1743-422X-8-321
PMCID: PMC3141683  PMID: 21703008
7.  Identification and validation of rice reference proteins for western blotting 
Journal of Experimental Botany  2011;62(14):4763-4772.
Studies of rice protein expression have increased considerably with the development of rice functional genomics. In order to obtain reliable expression results in western blotting, information on appropriate reference proteins is necessary for data normalization. To date, no published study has identified and systematically validated reference proteins suitable for the investigation of rice protein expression. In this study, nine candidate proteins were selected and their specific antibodies were obtained through immunization of rabbits with either recombinant proteins expressed in Escherichia coli or synthesized peptides. Western blotting was carried out to detect the expression of target proteins in a set of 10 rice samples representing different rice tissues/organs at different developmental stages. The expression stability of the proteins was analysed using geNorm and Microcal Origin 6.0 software. The results indicated that heat shock protein (HSP) and elongation factor 1-α (eEF-1α) were the most constantly expressed among all rice proteins tested throughout all developmental stages, while the proteins encoded by conventional internal reference genes fluctuated in amount. Comparison among the profiling of translation and transcription [expressed sequence tags (EST) and massively parallel signature sequencing (MPSS)] revealed that a correlation existed. Based on the standard curves derived from the antigen–antibody reaction, the concentrations of HSP and eEF-1α proteins in rice leaves were ∼0.12%. Under the present experimental conditions, the lower limits of detection for HSP and eEF-1α proteins in rice were 0.24 ng and 0.06 ng, respectively. In conclusion, the reference proteins selected in this study, and the corresponding antibodies, can be used in qualitative and quantitative analysis of rice proteins.
doi:10.1093/jxb/err084
PMCID: PMC3192993  PMID: 21705388
Antibody-based proteomics; rice (Oryza sativa L.); reference gene; reference protein; western blotting
8.  The X Protein of Hepatitis B Virus Inhibits Apoptosis in Hepatoma Cells through Enhancing the Methionine Adenosyltransferase 2A Gene Expression and Reducing S-Adenosylmethionine Production* 
The Journal of Biological Chemistry  2011;286(19):17168-17180.
The X protein (HBx) of hepatitis B virus (HBV) is involved in the development of hepatocellular carcinoma (HCC), and methionine adenosyltransferase 2A (MAT2A) promotes the growth of liver cancer cells through altering S-adenosylmethionine homeostasis. Thus, we speculated that a link between HBx and MAT2A may contribute to HCC development. In this study, the effects of HBx on MAT2A expression and cell apoptosis were investigated, and the molecular mechanism by which HBx and MAT2A regulate tumorigenesis was evaluated. Results from immunohistochemistry analyses of 37 pairs of HBV-associated liver cancer tissues/corresponding peritumor tissues showed that HBx and MAT2A are highly expressed in most liver tumor tissues. Our in vitro results revealed that HBx activates MAT2A expression in a dose-dependent manner in hepatoma cells, and such regulation requires the cis-regulatory elements NF-κB and CREB on the MAT2A gene promoter. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) further demonstrated that HBx facilitates the binding of NF-κB and CREB to MAT2A gene promoter. In addition, overexpression of HBx or MAT2A inhibits cell apoptosis, whereas knockdown of MAT2A expression stimulates apoptosis in hepatoma cells. Furthermore, we demonstrated that HBx reduces MAT1A expression and AdoMet production but enhances MAT2β expression. Thus, we proposed that HBx activates MAT2A expression through NF-κB and CREB signaling pathways to reduce AdoMet production, inhibit hepatoma cell apoptosis, and perhaps enhance HCC development. These findings should provide new insights into our understanding how the molecular mechanisms underline the effects of HBV infection on the production of MAT2A and the development of HCC.
doi:10.1074/jbc.M110.167783
PMCID: PMC3089560  PMID: 21247894
Apoptosis; Cancer Tumor Promoter; Chromatin Immunoprecipitation (ChiP); CREB; DNA-Protein Interaction; DNA Viruses; Gene Regulation; Hepatitis Virus; Oncogene; S-Adenosylmethionine (AdoMet)
9.  Plasmon resonance enhanced multicolour photodetection by graphene 
Nature communications  2011;2:579.
Graphene has the potential for high-speed, wide-band photodetection, but only with very low external quantum efficiency and no spectral selectivity. Here we report a dramatic enhancement of the overall quantum efficiency and spectral selectivity that enables multicolour photodetection, by coupling graphene with plasmonic nanostructures. We show that metallic plasmonic nanostructures can be integrated with graphene photodetectors to greatly enhance the photocurrent and external quantum efficiency by up to 1,500%. Plasmonic nanostructures of variable resonance frequencies selectively amplify the photoresponse of graphene to light of different wavelengths, enabling highly specific detection of multicolours. Being atomically thin, graphene photodetectors effectively exploit the local plasmonic enhancement effect to achieve a significant enhancement factor not normally possible with traditional planar semiconductor materials.
doi:10.1038/ncomms1589
PMCID: PMC4235953  PMID: 22146398
10.  Identification of Novel Subregions of LOH in Gastric Cancer and Analysis of the HIC1 and TOB1 Tumor Suppressor Genes in These Subregions 
Molecules and cells  2011;32(1):10.1007/s10059-011-2316-4.
Previously, we identified 3 overlapping regions showing loss of heterozygosity (LOH, R1-R3 from 11 to 30 cM) on chromosome 17 in 45 primary gastric cancers (GCs). The data indicated the presence of tumor suppressor genes (TSGs) on chromosome 17 involved in GC. Among the putative TSGs in these regions, HIC1 (in SR1) and TOB1 (in SR3) remain to be examined in GC. By immunohistochemistry (IHC), methylation-specific PCR (MSP) and western blot, we evaluated the expression and regulation status for HIC1 and TOB1 protein in GC. We narrowed down the deletion intervals on chromosome 17 and defined five smaller LOH subregions, SR1-SR5 (0.54 to 3.42 cM), in GC. We found that HIC1 had downregulated expression in 86% (91/106) and was methylated in 87% (26/30) of primary GCs. Of the primary GCs showing downregulation of HIC1 protein, 75% (18/24) had methylated HIC1 gene. TOB1 was either absent or expressed at reduced levels in 75% (73/97) of the GC samples. In addition, a general reduction was found in total and the ratio of unphosphorylated to phosphorylated TOB1 protein levels in the differentiated GC cell lines. Further analysis revealed significant simultaneous downregulation of both HIC1 and TOB1 protein in GC tissue microarray samples (67%, 52/78) and in primary GCs (65%, 11/17). These results indicate that silencing of HIC1 and TOB1 expression is a common occurrence in GC and may contribute to the development and progression of the disease.
doi:10.1007/s10059-011-2316-4
PMCID: PMC3855460  PMID: 21533545 CAMSID: cams3769
gastric cancer; HIC1; loss of heterozygosity; methylation; TOB1
11.  Gambogic acid enhances proteasome inhibitor-induced anticancer activity 
Cancer letters  2011;301(2):221-228.
Proteasome inhibition has emerged as a novel approach to anticancer therapy. Numerous natural compounds, such as gambogic acid, have been tested in vitro and in vivo as anticancer agents for cancer prevention and therapy. However, whether gambogic acid has chemosensitizing properties when combined with proteasome inhibitors in the treatment of malignant cells is still unknown. In an effort to investigate this effect, human leukemia K562 cells, mouse hepatocarcinoma H22 cells and H22 cell allografts were treated with gambogic acid, a proteasome inhibitor (MG132 or MG262) or the combination of both, followed by measurement of cellular viability, apoptosis induction and tumor growth inhibition. We report, for the first time, that: (i) the combination of natural product gambogic acid and the proteasome inhibitor MG132 or MG262 results in a synergistic inhibitory effect on growth of malignant cells and tumors in allograft animal models and (ii) there was no apparent systemic toxicity observed in the animals treated with the combination. Therefore, the findings presented in this study demonstrate that natural product gambogic acid is a valuable candidate to be used in combination with proteasome inhibitors, thus representing a compelling anticancer strategy.
doi:10.1016/j.canlet.2010.12.015
PMCID: PMC3662239  PMID: 21216092
Gambogic acid; Proteasome inhibitors; Antitumor activity; Synergistic effect
12.  Molecular insights into the heterogeneity of telomere reprogramming in induced pluripotent stem cells 
Cell Research  2011;22(4):757-768.
Rejuvenation of telomeres with various lengths has been found in induced pluripotent stem cells (iPSCs). Mechanisms of telomere length regulation during induction and proliferation of iPSCs remain elusive. We show that telomere dynamics are variable in mouse iPSCs during reprogramming and passage, and suggest that these differences likely result from multiple potential factors, including the telomerase machinery, telomerase-independent mechanisms and clonal influences including reexpression of exogenous reprogramming factors. Using a genetic model of telomerase-deficient (Terc−/− and Terc+/−) cells for derivation and passages of iPSCs, we found that telomerase plays a critical role in reprogramming and self-renewal of iPSCs. Further, telomerase maintenance of telomeres is necessary for induction of true pluripotency while the alternative pathway of elongation and maintenance by recombination is also required, but not sufficient. Together, several aspects of telomere biology may account for the variable telomere dynamics in iPSCs. Notably, the mechanisms employed to maintain telomeres during iPSC reprogramming are very similar to those of embryonic stem cells. These findings may also relate to the cloning field where these mechanisms could be responsible for telomere heterogeneity after nuclear reprogramming by somatic cell nuclear transfer.
doi:10.1038/cr.2011.201
PMCID: PMC3317559  PMID: 22184006
telomere; telomerase; recombination; iPSCs; reprogramming
13.  Crystallization and preliminary crystallographic studies of a cysteine protease inhibitor from the human nematode parasite Ascaris lumbricoides  
A recombinant cysteine protease inhibitor from the human nematode parasite A. lumbricoides has been overexpressed in E. coli, purified and crystallized. Diffraction data were collected to 2.1 Å resolution.
The cysteine protease inhibitor from Ascaris lumbricoides, a roundworm that lives in the human intestine, may be involved in the suppression of human immune responses. Here, the molecular cloning, protein expression and purification, preliminary crystallization and crystallographic characterization of the cysteine protease inhibitor from A. lumbricoides are reported. The rod-shaped crystal belonged to space group C2, with unit-cell parameters a = 99.40, b = 37.52, c = 62.92 Å, β = 118.26°. The crystal diffracted to 2.1 Å resolution and contained two molecules in the asymmetric unit.
doi:10.1107/S1744309110050773
PMCID: PMC3034614  PMID: 21301092
cysteine protease inhibitors; nematode parasites; Ascaris lumbricoides
14.  Direct reprogramming of Sertoli cells into multipotent neural stem cells by defined factors 
Cell Research  2011;22(1):208-218.
Multipotent neural stem/progenitor cells hold great promise for cell therapy. The reprogramming of fibroblasts to induced pluripotent stem cells as well as mature neurons suggests a possibility to convert a terminally differentiated somatic cell into a multipotent state without first establishing pluripotency. Here, we demonstrate that Sertoli cells derived from mesoderm can be directly converted into a multipotent state that possesses neural stem/progenitor cell properties. The induced neural stem/progenitor cells (iNSCs) express multiple NSC-specific markers, exhibit a global gene-expression profile similar to normal NSCs, and are capable of self-renewal and differentiating into glia and electrophysiologically functional neurons. iNSC-derived neurons stain positive for tyrosine hydroxylase (TH), γ-aminobutyric acid, and choline acetyltransferase. In addition, iNSCs can survive and generate synapses following transplantation into the dentate gyrus. Generation of iNSCs may have important implications for disease modeling and regenerative medicine.
doi:10.1038/cr.2011.175
PMCID: PMC3351918  PMID: 22064700
direct conversion; neural stem cell; multipotent; transdifferentiation; transplantation
15.  Effects of cumulus cells removal after 6 h co-incubation of gametes on the outcomes of human IVF 
Purpose
To investigate the effects of cumulus cells removal after 6 h co-incubation of gametes on the fertilization, polyspermy, multinucleation and clinical pregnancy rates in human IVF.
Methods
A total of 1,200 IVF-ET cycles undergoing 6 h co-incubation of gametes in 2009 were included in this study. Inclusion criteria were: female age <38 years, first IVF treatment, with bi-ovary and normal ovarian response, e.g., 4 ~ 20 oocytes could be obtained. A 6 h period of co-incubation was applied in all IVF cycles. According to the history of infertility, cumulus cells were mechanically removed either 6 h post-insemination or 20 h post-insemination. For couples with primary infertility, or unexplained infertility, or mild oligospermia or asthenospermia, the cumulus cells were removed at 6 h of insemination for the polar body observation (6 h group, n = 565). Of these, 80 cycles received early rescue ICSI due to fertilization failure or low fertilization rate at 6 h of insemination. For couples with secondary infertility and normal semen analysis, the cumulus cells were removed at 20 h of insemination as routine (20 h group, n = 635). Of these, three cycles received late rescue ICSI due to fertilization failure at 20 h of insemination. Normal fertilization, polyspermy (≥3PN), multinucleation and clinical pregnancy rates were compared between the two groups (rescue ICSI cycles were not included in the comparison in both groups).
Results
Significant difference (P < 0.05) was observed between the groups regarding polyspermy rates (7.48% in 6 h group and 9.22% in 20 h group). No difference was observed between the groups regarding normal fertilization rates (2PN rate) (64.89% in 6 h group and 65.74% in 20 h group). No difference was observed between the groups regarding multinucleation and clinical pregnancy rates (11.01% and 65.15% in 6 h group, 10.75% and 66.93% in 20 h group, respectively). The clinical pregnancy rate was 51.43% in cycles receiving early rescue ICSI, while no clinical pregnancy was obtained in cycles receiving late rescue ICSI.
Conclusion
The present results indicate that cumulus cells removal at 6 h of insemination is a relatively safe operation, which yielded comparable normal fertilization rate, multinucleation and clinical pregnancy rates compared with 20 h group. This protocol may be beneficial for early obsevation of fertilization failure and make early rescue ICSI possible.
doi:10.1007/s10815-011-9630-9
PMCID: PMC3241845  PMID: 21898104
In-vitro fertilization; Short co-incubation; Cumulus cells removal; Polyspermy; Clinical pregnancy; Rescue ICSI
16.  mir-35 is involved in intestine cell G1/S transition and germ cell proliferation in C. elegans 
Cell Research  2011;21(11):1605-1618.
MicroRNA (miRNA) regulates gene expression in many cellular events, yet functions of only a few miRNAs are known in C. elegans. We analyzed the function of mir-35-41 unique to the worm, and show here that mir-35 regulates the G1/S transition of intestinal cells and germ cell proliferation. Loss of mir-35 leads to a decrease of nuclei numbers in intestine and distal mitotic gonad, while re-introduction of mir-35 rescues the mutant phenotypes. Genetic analysis indicates that mir-35 may act through Rb/E2F and SCF pathways. Further bioinformatic and functional analyses demonstrate that mir-35 targets evolutionally conserved lin-23 and gld-1. Together, our study reveals a novel function of mir-35 family in cell division regulation.
doi:10.1038/cr.2011.102
PMCID: PMC3364723  PMID: 21691303
miRNA; C. elegans; mir-35; G1/S transition; germ cell proliferation
17.  Verticillin A Overcomes Apoptosis Resistance in Human Colon Carcinoma through DNA methylation-dependent Upregulation of BNIP3 
Cancer research  2011;71(21):6807-6816.
Drug resistance is a major cause of failure in cancer chemotherapy. Therefore, identification and combined use of adjuvant compounds that can overcome drug resistance may improve the efficacy of cancer therapy. We screened extracts of Verticillium sp-infected mushrooms for anti-tumor compounds and identified the compound Verticillin A as an inducer of hepatoma cell apoptosis in vitro and an inhibitor of tumor xenograft growth in vivo. Verticillin A exhibited a potent apoptosis sensitizing activity in human colon carcinoma cells exposed to TRAIL or Fas in vitro. Furthermore, Verticillin A effectively sensitized metastatic human colon carcinoma xenograft to TRAIL-mediated growth inhibition in vivo. At the molecular level, we observed that Verticillin A induces cell cycle arrest in the G2 phase of the cell cycle in human colon carcinoma cells, markedly upregulating BNIP3 in both hepatoma and colon carcinoma cells. Notably, silencing BNIP3 decreased the sensitivity of tumor cells to Verticillin A-induced apoptosis in the absence or presence of TRAIL. We found that the BNIP3 promoter are methylated in both human hepatoma and colon carcinoma cells and tumor specimens. Verticillin A upregulated the expression of a panel of genes known to be regulated at the level of DNA methylation, in support of the concept that Verticillin A may act by demethylating the BNIP3 promoter to upregulate BNIP3 expression. Taken together, our findings identify Verticillin A as a potent apoptosis sensitizer with great promise for further development as an adjuvant agent to overcome drug resistance in human cancer therapy.
doi:10.1158/0008-5472.CAN-11-1575
PMCID: PMC3206150  PMID: 21911457
Verticillin A; Drug Resistance; TRAIL; Fas; BNIP3
18.  G-protein alpha-s and -12 subunits are involved in androgen-stimulated PI3K activation and androgen receptor transactivation in prostate cancer cells 
The Prostate  2011;71(12):1276-1286.
BACKGROUND
The androgen receptor (AR) is a ligand-dependent transcription factor that mediates androgenic hormone action in cells. We recently demonstrated the involvement of phosphoinositide 3-OH kinase (PI3K) p110beta in AR transactivation and gene expression. In this study, we determined the upstream signals that lead to PI3K/p110beta activation and AR transactivation after androgen stimulation.
METHODS
Human prostate cancer LAPC-4 and 22Rv1 cell lines were used for the experiments. AR transactivation was assessed using an androgen responsive element-driven luciferase (ARE-LUC) assay. Cell proliferation was examined using BrdU incorporation and MTT assays. Target genes were silenced using small interfering RNA (siRNA) approach. Gene expression was evaluated at the mRNA level (real-time RT-PCR) and protein level (Western blot). PI3K kinase activities were measured using immunoprecipitation-based in vitro kinase assay. The AR-DNA binding activity was determined using Chromatin-immunoprecipitation (ChIP) assay.
RESULTS
First, at the cellular plasma membrane, disrupting the integrity of caveolae microdomain with methyl-β- cyclodextrin (M-β-CD) abolished androgen-induced AR transactivation and gene expression. Then, knocking down caveolae structural proteins caveolin-1 or -2 with the gene-specific siRNAs significantly reduced androgen-induced AR transactivation. Next, silencing Gαs and Gα12 genes but not other G-proteins blocked androgen-induced AR transactivation and cell proliferation. Consistently, overexpression of Gαs or Gα12 active mutants enhanced androgen-induced AR transactivation, of which Gαs active mutant sensitized the AR to castration-level of androgen (R1881). Most interestingly, knocking down Gαs but not Gα12 subunit significantly suppressed androgen-stimulated PI3K p110beta activation. However, chromatin-immunoprecipitation (ChIP) analysis revealed that both Gαs or Gα12 subunits are involved in androgen-induced AR interaction with the AR target gene PSA promoter region.
CONCLUSION
These data suggest that caveolae-associated G-protein alpha subunits are involved in AR transactivation by modulating the activities of different PI3K isoforms.
doi:10.1002/pros.21345
PMCID: PMC3143312  PMID: 21308712
prostate cancer; caveolae; androgen receptor; G-protein
19.  Identification of Novel Subregions of LOH in Gastric Cancer and Analysis of the HIC1 and TOB1 Tumor Suppressor Genes in These Subregions 
Molecules and Cells  2011;32(1):47-55.
Previously, we identified 3 overlapping regions showing loss of heterozygosity (LOH, R1-R3 from 11 to 30 cM) on chromosome 17 in 45 primary gastric cancers (GCs). The data indicated the presence of tumor suppressor genes (TSGs) on chromosome 17 involved in GC. Among the putative TSGs in these regions, HIC1 (in SR1) and TOB1 (in SR3) remain to be examined in GC. By immunohistochemistry (IHC), methylation-specific PCR (MSP) and western blot, we evaluated the expression and regulation status for HIC1 and TOB1 protein in GC. We narrowed down the deletion intervals on chromosome 17 and defined five smaller LOH subregions, SR1-SR5 (0.54 to 3.42 cM), in GC. We found that HIC1 had downregulated expression in 86% (91/106) and was methylated in 87% (26/30) of primary GCs. Of the primary GCs showing downregulation of HIC1 protein, 75% (18/24) had methylated HIC1 gene. TOB1 was either absent or expressed at reduced levels in 75% (73/97) of the GC samples. In addition, a general reduction was found in total and the ratio of unphosphorylated to phosphorylated TOB1 protein levels in the differentiated GC cell lines. Further analysis revealed significant simultaneous downregulation of both HIC1 and TOB1 protein in GC tissue microarray samples (67%, 52/78) and in primary GCs (65%, 11/17). These results indicate that silencing of HIC1 and TOB1 expression is a common occurrence in GC and may contribute to the development and progression of the disease.
doi:10.1007/s10059-011-2316-4
PMCID: PMC3855460  PMID: 21533545
gastric cancer; HIC1; loss of heterozygosity; methylation; TOB1
20.  Knockdown of Akt1 Promotes Akt2 Upregulation and Resistance to Oxidative-Stress-Induced Apoptosis Through Control of Multiple Signaling Pathways 
Abstract
The Akt signaling pathway plays a key role in promoting the survival of various types of cells from stress-induced apoptosis, and different members of the Akt family display distinct physiological roles. Previous studies have shown that in response to UV irradiation, Akt2 is sensitized to counteract the induced apoptosis. However, in response to oxidative stress such as hydrogen peroxide, it remains to be elucidated what member of the Akt family would be activated to initiate the signaling cascades leading to resistance of the induced apoptosis. In the present study, we present the first evidence that knockdown of Akt1 enhances cell survival under exposure to 50 μM H2O2. This survival is derived from selective upregulation and activation of Akt2 but not Akt3, which initiates 3 major signaling cascades. First, murine double minute 2 (MDM2) is hyperphosphorylated, which promotes p53 degradation and attenuates its Ser-15 phosphorylation, significantly attenuating Bcl-2 homologous antagonist killer (Bak) upregulation. Second, Akt2 activation inactivates glycogen synthase kinase 3 beta (GSK-3β) to promote stability of myeloid leukemia cell differentiation protein 1 (MCL-1). Finally, Akt2 activation promotes phosphorylation of FOXO3A toward cytosolic export and thus downregulates Bim expression. Overexpression of Bim enhances H2O2-induced apoptosis. Together, our results demonstrate that among the Akt family members, Akt2 is an essential kinase in counteracting oxidative-stress-induced apoptosis through multiple signaling pathways. Antioxid. Redox Signal. 15, 1–17.
doi:10.1089/ars.2010.3560
PMCID: PMC3110099  PMID: 21303257
21.  Overcoming Trastuzumab Resistance in Breast Cancer by Targeting Dysregulated Glucose Metabolism 
Cancer research  2011;71(13):4585-4597.
Trastuzumab shows remarkable efficacy in treatment of ErbB2-positive breast cancers when used alone or in combination with other chemotherapeutics. However, acquired resistance develops in most treated patients, necessitating alternate treatment strategies. Increased aerobic glycolysis is a hallmark of cancer and inhibition of glycolysis may offer a promising strategy to preferentially kill cancer cells. In this study, we investigated the antitumor effects of trastuzumab in combination with glycolysis inhibitors in ErbB2-positive breast cancer. We found that trastuzumab inhibits glycolysis via downregulation of heat shock factor 1 (HSF1) and lactate dehydrogenase A (LDH-A) in ErbB2-positive cancer cells, resulting in tumor growth inhibition. Moreover, increased glycolysis via HSF1 and LDH-A contributes to trastuzumab resistance. Importantly, we found that combining trastuzumab with glycolysis inhibition synergistically inhibited trastuzumab-sensitive and -resistant breast cancers in vitro and in vivo, due to more efficient inhibition of glycolysis. Taken together, our findings show how glycolysis inhibition can dramatically enhance the therapeutic efficacy of trastuzumab in ErbB2-positive breast cancers, potentially useful as a strategy to overcome trastuzumab resistance.
doi:10.1158/0008-5472.CAN-11-0127
PMCID: PMC3129363  PMID: 21498634
Warburg effect; glycolysis; HSF1; LDH-A; trastuzumab; ErbB2; resistance
22.  Local interstitial delivery of z-butylidenephthalide by polymer wafers against malignant human gliomas 
Neuro-Oncology  2011;13(6):635-648.
We have shown that the natural compound z-butylidenephthalide (Bdph), isolated from the chloroform extract of Angelica sinensis, has antitumor effects. Because of the limitation of the blood-brain barrier, the Bdph dosage required for treatment of glioma is relatively high. To solve this problem, we developed a local-release system with Bdph incorporated into a biodegradable polyanhydride material, p(CPP-SA; Bdph-Wafer), and investigated its antitumor effects. On the basis of in vitro release kinetics, we demonstrated that the Bdph-Wafer released 50% of the available Bdph by the sixth day, and the release reached a plateau phase (90% of Bdph) by the 30th day. To investigate the in situ antitumor effects of the Bdph-Wafer on glioblastoma multiforme (GBM), we used 2 xenograft animal models—F344 rats (for rat GBM) and nude mice (for human GBM)—which were injected with RG2 and DBTRG-05MG cells, respectively, for tumor formation and subsequently treated subcutaneously with Bdph-Wafers. We observed a significant inhibitory effect on tumor growth, with no significant adverse effects on the rodents. Moreover, we demonstrated that the antitumor effect of Bdph on RG2 cells was via the PKC pathway, which upregulated Nurr77 and promoted its translocation from the nucleus to the cytoplasm. Finally, to study the effect of the interstitial administration of Bdph in cranial brain tumor, Bdph-Wafers were surgically placed in FGF-SV40 transgenic mice. Our Bdph-Wafer significantly reduced tumor size in a dose-dependent manner. In summary, our study showed that p(CPP-SA) containing Bdph delivered a sufficient concentration of Bdph to the tumor site and effectively inhibited the tumor growth in the glioma.
doi:10.1093/neuonc/nor021
PMCID: PMC3107093  PMID: 21565841
carmustine (BCNU); glioblastoma multiforme (GBM); p(CPP-SA) wafer; z-butylidenephthalide (Bdph)
23.  Peripheral Nerve Injury Leads to Working Memory Deficits and Dysfunction of the Hippocampus by Upregulation of TNF-α in Rodents 
Neuropsychopharmacology  2011;36(5):979-992.
Patients with chronic pain usually suffer from working memory deficits, which may decrease their intellectual ability significantly. Despite intensive clinical studies, the mechanism underlying this form of memory impairment remains elusive. In this study, we investigated this issue in the spared nerve injury (SNI) model of neuropathic pain, a most common form of chronic pain. We found that SNI impaired working memory and short-term memory in rats and mice. To explore the potential mechanisms, we studied synaptic transmission/plasticity in hippocampus, a brain region critically involved in memory function. We found that frequency facilitation, a presynaptic form of short-term plasticity, and long-term potentiation at CA3–CA1 synapses were impaired after SNI. Structurally, density of presynaptic boutons in hippocampal CA1 synapses was reduced significantly. At the molecular level, we found that tumor necrosis factor-α (TNF-α) increased in cerebrospinal fluid, in hippocampal tissue and in plasma after SNI. Intracerebroventricular or intrahippocampal injection of recombinant rat TNF mimicked the effects of SNI in naive rats, whereas inhibition of TNF-α or genetic deletion of TNF receptor 1 prevented both memory deficits and synaptic dysfunction induced by SNI. As TNF-α is critical for development of neuropathic pain, we suggested that the over-production of TNF-α following peripheral nerve injury might lead to neuropathic pain and memory deficits, simultaneously.
doi:10.1038/npp.2010.236
PMCID: PMC3077267  PMID: 21289602
spared nerve injury; chronic neuropathic pain; working memory; long-term potentiation; presynaptic boutons; tumor necrosis factor-α; pain/analgesics; learning & memory; neuropharmacology; plasticity; peripheral nerve injury; chronic neuropathic pain; working memory; long-term potentiation; presynaptic boutons; tumor necrosis factor alpha
24.  Germline competency of parthenogenetic embryonic stem cells from immature oocytes of adult mouse ovary 
Human Molecular Genetics  2011;20(7):1339-1352.
Parthenogenetic embryonic stem cells (pESCs) have been generated in several mammalian species from parthenogenetic embryos that would otherwise die around mid-gestation. However, previous reports suggest that pESCs derived from in vivo ovulated (IVO) mature oocytes show limited pluripotency, as evidenced by low chimera production, high tissue preference and especially deficiency in germline competence, a critical test for genetic integrity and pluripotency of ESCs. Here, we report efficient generation of germline-competent pESC lines (named as IVM pESCs) from parthenogenetic embryos developed from immature oocytes of adult mouse ovaries following in vitro maturation (IVM) and artificial activation. In contrast, pESCs derived from IVO oocytes show defective germline competence, consistent with previous reports. Further, IVM pESCs resemble more ESCs from fertilized embryos (fESCs) than do IVO pESCs on genome-wide DNA methylation and global protein profiles. In addition, IVM pESCs express higher levels of Blimp1, Lin28 and Stella, relative to fESCs, and in their embryoid bodies following differentiation. This may indicate differences in differentiation potentially to the germline. The mechanisms for acquisition of pluripotency and germline competency of IVM pESCs from immature oocytes remain to be determined.
doi:10.1093/hmg/ddr016
PMCID: PMC3049357  PMID: 21239471
25.  A conditional Granger causality model approach for group analysis in functional MRI 
Magnetic resonance imaging  2011;29(3):418-433.
Granger causality model (GCM) derived from multivariate vector autoregressive models of data has been employed for identifying effective connectivity in the human brain with functional MR imaging (fMRI) and to reveal complex temporal and spatial dynamics underlying a variety of cognitive processes. In the most recent fMRI effective connectivity measures, pairwise GCM has commonly been applied based on single voxel values or average values from special brain areas at the group level. Although a few novel conditional GCM methods have been proposed to quantify the connections between brain areas, our study is the first to propose a viable standardized approach for group analysis of an fMRI data with GCM. To compare the effectiveness of our approach with traditional pairwise GCM models, we applied a well-established conditional GCM to pre-selected time series of brain regions resulting from general linear model (GLM) and group spatial kernel independent component analysis (ICA) of an fMRI dataset in the temporal domain. Datasets consisting of one task-related and one resting-state fMRI were used to investigate connections among brain areas with the conditional GCM method. With the GLM detected brain activation regions in the emotion related cortex during the block design paradigm, the conditional GCM method was proposed to study the causality of the habituation between the left amygdala and pregenual cingulate cortex during emotion processing. For the resting-state dataset, it is possible to calculate not only the effective connectivity between networks but also the heterogeneity within a single network. Our results have further shown a particular interacting pattern of default mode network (DMN) that can be characterized as both afferent and efferent influences on the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC). These results suggest that the conditional GCM approach based on a linear multivariate vector autoregressive (MVAR) model can achieve greater accuracy in detecting network connectivity than the widely used pairwise GCM, and this group analysis methodology can be quite useful to extend the information obtainable in fMRI.
doi:10.1016/j.mri.2010.10.008
PMCID: PMC3063394  PMID: 21232892
Granger causality; fMRI; group analysis; effective connectivity

Results 1-25 (5848)