Generation of recombinant influenza A virus without M2 ion-channel protein by introduction of a point mutation at the 5′ end of the viral intron

The aim of this study was to inhibit influenza virus M2 protein expression by mutating the splicing signal of the M gene. Mutations were introduced into the GU dinucleotide sequence at the 5′-proximal splicing site of the M gene (corresponding to nt 52-53 of M cRNA). Transfected cells expressing mutated M viral ribonucleoproteins failed to generate M2 mRNA. Interestingly, recombinant viruses with mutations at the dinucleotide sequence were viable, albeit attenuated, in cell culture. These recombinants failed to express M2 mRNA and M2 protein. These observations demonstrated that the GU invariant dinucleotide sequence at the 5′-proximal splicing site of M gene is essential for M2 mRNA synthesis. These results also indicated that the M2 ion-channel protein is critical, but not essential, for virus replication in cell culture. This approach may provide a new way of producing attenuated influenza A virus. © 2005 SGM.postprin

RhoE/ROCK signaling modulates chemoresistance in HCC through IL6/JAK2/STAT3 pathways

Conference Theme: New Horizons in Cancer Research Conference: Harnessing Breakthroughs - Targeting CuresPoster Session B: Tumor Biology: no. B40Liver cancer (hepatocellular carcinoma, HCC) is a major malignancy worldwide and the second commonest fatal cancer in Southeast Asia and China including Hong Kong, due to the high prevalence of hepatitis B viral infection. HCC is highly chemoresistant, limiting treatment options to patients. There is an urgent need to delineate the underlying molecular mechanism of HCC chemoresistance so as to identify novel therapeutic targets for this aggressive cancer. Deregulation of Rho GTPase pathway is demonstrated to play important roles in HCC tumorigenesis. RhoE/Rnd3 belongs to the Rnd subfamily of the Rho GTPase which lacks the intrinsic GTPase activity. In our previous study, we have shown that RhoE is frequently downregulated in human HCCs and acts as a metastasis suppressor, whereas ROCK2 is upregulated in human HCCs. In this study, we aimed to investigate whether RhoE is also involved in the regulation of chemoresistance in HCC. Using short-hairpin RNA and ...published_or_final_versio

Biology of influenza a virus

The outbreaks of avian influenza A virus in poultry and humans over the last decade posed a pandemic threat to human. Here, we discuss the basic classification and the structure of influenza A virus. The viral genome contains eight RNA viral segments and the functions of viral proteins encoded by this genome are described. In addition, the RNA transcription and replication of this virus are reviewed. © 2007 New York Academy of Sciences.link_to_subscribed_fulltex

Processing of facial emotions: Pilot EEG and fMRI data

We present preliminary results of healthy volunteers who underwent EEG and fMRI experiments in which they performed an implicit (gender discrimination) task and an explicit (emotional or neutral expression) task. The same stimuli from a standardized set of pictures (JACEE 1988) were used in a block design paradigm in both sessions. Combined analysis of the electrophysiological and haemodynamic data was done to integrate the early temporal EEG components with the fMRI spatial activations. This work demonstrates a multimodal approach to understanding the temporal and spatial neurological bases of social developmental disorders such as autism and childhood depression.link_to_subscribed_fulltex

Liver tumor-initiating cells as a therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignancy worldwide and has poor prognosis. Existing treatment modalities, including surgery, chemotherapy, and radiofrequency ablation, which target tumor bulk, have demonstrated limited therapeutic efficacy. In the past 10years, accumulating evidence has supported the existence of cancer stem cells (CSCs) or tumor initiating cells (T-ICs) within tumors including HCC. Identification of liver T-ICs and the signaling pathways that they are involved in may shed light on novel therapeutic strategies against this deadly disease. In this review, we will discuss recent progresses made in the research of liver T-ICs with regard to identification, functional characterization, regulation and therapeutic implications.link_to_subscribed_fulltex

Antiviral effect of a selective COX-2 inhibitor on H5N1 infection in vitro

A selective cyclooxygenase-2 (COX-2) inhibitor has been previously shown to suppress the hyper-induced pro-inflammatory responses in H5N1 infected primary human cells. Here, we demonstrate that COX-2 inhibitors suppress H5N1 virus replication in human macrophages suggesting that H5N1 virus replication (more so than seasonal H1N1 virus) is dependent on activation of COX-2 dependent signaling pathways in host cells. COX-2 and its downstream signaling pathways deserve detailed investigation as a novel therapeutic target for treatment of H5N1 disease. © 2011 Elsevier B.V.link_to_subscribed_fulltex

Lupeol targets liver tumor-initiating cells through phosphatase and tensin homolog modulation

Liver tumor-initiating cells (T-ICs) are capable of self-renewal and tumor initiation and are more chemoresistant to chemotherapeutic drugs. The current therapeutic strategies for targeting stem cell self-renewal pathways therefore represent rational approaches for cancer prevention and treatment. In the present study, we found that Lup-20(29)-en-3β-ol (lupeol), a triterpene found in fruits and vegetables, inhibited the self-renewal ability of liver T-ICs present in both hepatocellular carcinoma (HCC) cell lines and clinical HCC samples, as reflected by hepatosphere formation. Furthermore, lupeol inhibited in vivo tumorigenicity in nude mice and down-regulated CD133 expression, which was previously shown to be a T-IC marker for HCC. In addition, lupeol sensitized HCC cells to chemotherapeutic agents through the phosphatase and tensin homolog (PTEN)-Akt-ABCG2 pathway. PTEN plays a crucial role in the self-renewal and chemoresistance of liver T-ICs; down-regulation of PTEN by a lentiviral-based approach reversed the effect of lupeol on liver T-ICs. Using an in vivo chemoresistant HCC tumor model, lupeol dramatically decreased the tumor volumes of MHCC-LM3 HCC cell line-derived xenografts, and the effect was equivalent to that of combined cisplatin and doxorubicin treatment. Lupeol exerted a synergistic effect without any adverse effects on body weight when combined with chemotherapeutic drugs. Conclusion: Our results suggest that lupeol may be an effective dietary phytochemical that targets liver T-ICs. © 2010 American Association for the Study of Liver Diseases.link_to_OA_fulltex

Stress and psychological impact on SARS patients during the outbreak

Objective: To examine stress and psychological impact in severe acute respiratory syndrome (SARS) patients during the 2003 outbreak. SARS is a novel, highly infectious pneumonia, and its psychological impact is still unclear. Method: At the peak of the outbreak, SARS patients (n = 79) and healthy control subjects (n = 145) completed the Perceived Stress Scale (PSS) and documented a range of psychological responses. Groups were balanced for age, sex, education, and living circumstances. Results: Stress was significantly higher in SARS patients than in healthy control subjects. Stress correlated significantly with negative psychological effects. Of SARS patients, 39% (n = 30) were infected health care workers; these individuals reported significantly more fatigue and worries about health than did other patients. Of patients, 25% (n = 20) requested psychological follow-up. Conclusions: General stress and negative psychological effects are increased in SARS patients, particularly among infected health care workers. This may increase the risk of mood and stress-related disorders. Functional impairment is apparent in the postrecovery phase.link_to_subscribed_fulltex

A Novel Splice Variant to NCOR2 as Biomarker for Tamoxifen Resistant Breast Cancer

More than two-thirds of all breast cancers are estrogen receptor (ER) positive for which Tamoxifen revolutionized their management as adjuvant treatment to prevent cancer recurrence. Almost half of these patients eventually develop resistance. The mechanisms underlying tamoxifen resistance are not yet well understood. There is no robust biomarker to reliably predict those who will be resistant. By the time drug resistance is established, the cancer has already progressed and sometimes metastasized. We have identified a novel splice variant, BQ323636.1 which retains only the N-terminus repression domain 1 of the NCOR2 wildtype protein. Overexpression of BQ conferred resistance to tamoxifen in both in vitro and in orthotopic mouse model. Mechanistically, co-immunoprecipitation showed BQ could bind to NCOR2 and inhibit the formation of co-repressor complex for suppression of the ER signaling. Consistently, BQ overexpression compromised the suppressive role of NCOR2 in regulating estrogen-response element activity and rescued transcriptional suppression of tamoxifen on ER-target genes. We generated a monoclonal antibody specific for BQ used to predict patients’ responses to tamoxifen treatment. Immunohistochemistry was performed on tissue microarray of 355 patients with clinical follow-up data of more than 10 years, who had ER positive primary breast carcinoma and had received adjuvant tamoxifen treatment. Nuclear BQ overexpression was significantly associated with tamoxifen resistance by Chi-square test, p= 3.90 x 10-6 with a sensitivity of 51.4% and specificity of 72.9%. In tamoxifen treated patients, nuclear BQ overexpression was significantly correlated with cancer metastasis, p= 1.72 x 10-6, and also significantly associated with disease relapse, p=3.47 x 10-4. Consistent with its role in predicting tamoxifen resistance, nuclear BQ was significantly associated with poorer survival by Kaplan-Meier estimate (Log-rank test) p=6.28 x 10-5 and p=1.31 x 10-4 for overall survival and disease-specific survival respectively. The development of such reliable biomarker would enable appropriate alternative therapy to be given at an early stage, thus saving the patient from the side effects as well as risk of inappropriate treatment by tamoxifen

Detection of SARS Coronavirus in Patients with Severe Acute Respiratory Syndrome by Conventional and Real-Time Quantitative Reverse Transcription-PCR Assays

Background: A novel coronavirus (CoV) was recently identified as the agent for severe acute respiratory syndrome (SARS). We compared the abilities of conventional and real-time reverse transcription-PCR (RT-PCR) assays to detect SARS CoV in clinical specimens. Methods: RNA samples isolated from nasopharyngeal aspirate (NPA; n = 170) and stool (n = 44) were reverse-transcribed and tested by our in-house conventional RT-PCR assay. We selected 98 NPA and 37 stool samples collected at different times after the onset of disease and tested them in a real-time quantitative RT-PCR specific for the open reading frame (ORF) 1b region of SARS CoV. Detection rates for the conventional and real-time quantitative RT-PCR assays were compared. To investigate the nature of viral RNA molecules in these clinical samples, we determined copy numbers of ORF 1b and nucleocapsid (N) gene sequences of SARS CoV. Results: The quantitative real-time RT-PCR assay was more sensitive than the conventional RT-PCR assay for detecting SARS CoV in samples collected early in the course of the disease. Real-time assays targeted at the ORF 1b region and the N gene revealed that copy numbers of ORF 1b and N gene sequences in clinical samples were similar. Conclusions: NPA and stool samples can be used for early diagnosis of SARS. The real-time quantitative RT-PCR assay for SARS CoV is potentially useful for early detection of SARS CoV. Our results suggest that genomic RNA is the predominant viral RNA species in clinical samples. © 2004 American Association for Clinical Chemistry.link_to_subscribed_fulltex