Browsing by Author "Chen, Yi-Ming Arthur"

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Characterization of the Drug Resistance Profiles of Patients Infected with CRF07_BC Using Phenotypic Assay and Ultra-Deep Pyrosequencing
(2017-01-20)
Huang, Szu-Wei
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Li, Wei-You
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Wang, Wen-Hung
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Lin, Yu-Ting
;
Chou, Chih-Hung
The usefulness of ultra-deep pyrosequencing (UDPS) for the diagnosis of HIV-1 drug resistance (DR) remains to be determined. Previously, we reported an explosive outbreak of HIV-1 circulating recombinant form (CRF) 07_BC among injection drug users (IDUs) in Taiwan in 2004. The goal of this study was to characterize the DR of CRF07_BC strains using different assays including UDPS. Seven CRF07_BC isolates including 4 from early epidemic (collected in 2004 - 2005) and 3 from late epidemic (collected in 2008) were obtained from treatment-naive patient\'s peripheral blood mononuclear cells. Viral RNA was extracted directly from patient\'s plasma or from cultural supernatant and the pol sequences were determined using RT-PCR sequencing or UDPS. For comparison, phenotypic drug susceptibility assay using MAGIC-5 cells (in-house phenotypic assay) and Antivirogram were performed. In-house phenotypic assay showed that all the early epidemic and none of the late epidemic CRF07_BC isolates were resistant to most protease inhibitors (PIs) (4.4 - 47.3 fold). Neither genotypic assay nor Antivirogram detected any DR mutations. UDPS showed that early epidemic isolates contained 0.01 +/- 0.08% of PI DR major mutations. Furthermore, the combinations of major and accessory PI DR mutations significantly correlated with the phenotypic DR. The in-house phenotypic assay is superior to other conventional phenotypic assays in the detection of DR variants with a frequency as low as 0.01%.
Functional Characterization of Glycine N-Methyltransferase and Its Interactive Protein DEPDC6/DEPTOR in Hepatocellular Carcinoma
(2012-02-01)
Yen, Chia-Hung
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Lu, Yao-Cheng
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Li, Chung-Hsien
;
Lee, Cheng-Ming
;
Chen, Chia-Yen
Glycine N-methyltransferase (GNMT) is a tumor suppressor for hepatocellular carcinoma (HCC). High rates of Gnmt knockout mice developed HCC. Epigenetic alteration and dysregulation of several pathways including wingless-type MMTV integration site (Wnt), mitogen-activated protein kinase (MAPK) and Janus kinase and signal transducer and activator of transcription (JAK-STAT) are associated with HCC development in Gnmt knockout mice. We hypothesized that GNMT may regulate signal transduction through interacting with other proteins directly. In this report, we identified a mammalian target of rapamycin (mTOR) inhibitor (DEP domain containing MTOR-interacting protein (DEPDC6/DEPTOR)) as a GNMT-binding protein by using yeast two-hybrid screening. Fluorescence resonance energy transfer assay demonstrated that the C-terminal half of GNMT interact with the PSD-95/DIg1/ZO-1 (PDZ) domain of DEPDC6/DEPTOR. Immunohistochemical staining showed that 27.5% (14/51) of HCC patients had higher expression levels of DEPDC6/DEPTOR in the tumorous tissues than in tumor-adjacent tissues, especially among HCC patients with hepatitis B viral infection (odds ratio 10.3, 95% confidence interval (CI) 1.05-11.3) or patients with poor prognosis (death hazard ratio 4.51, 95% CI 1.60-12.7). In terms of molecular mechanism, knockdown of DEPDC6/DEPTOR expression in HuH-7 cells caused S6K and 4E-BP activation, but suppressed Akt. Overexpression of DEPDC6/DEPTOR activated Akt and increased survival of HCC cells. Overexpression of GNMT caused activation of mTOR/raptor downstream signaling and delayed G2/M cell cycle progression, which altogether resulted in cellular senescence. Furthermore, GNMT reduced proliferation of HuH-7 cells and sensitized them to rapamycin treatment both in vitro and in vivo. In conclusion, GNMT regulates HOC growth in part through interacting with DEPDC6/DEPTOR and modulating mTOR/raptor signaling pathway. Both GNMT and DEPDC6/DEPTOR are potential targets for developing therapeutics for HCC. Online address: http://www.molmed.org doi: 10.2119/molmed.2011.00331
Functional Characterization of Glycine N-Methyltransferase and Its Interactive Protein DEPDC6/DEPTOR in Hepatocellular Carcinoma (vol 18, pg 286, 2012)
(2012-03-01)
Yen, Chia-Hung
;
Lu, Yao-Cheng
;
Li, Chung-Hsien
;
Lee, Cheng-Ming
;
Chen, Chia-Yen
Incidence of autoimmune diseases in a nationwide HIV/AIDS patient cohort in Taiwan, 2000-2012
(2017-04-01)
Yen, Yung-Feng
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Chuang, Pei-Hung
;
Jen, I-An
;
Chen, Marcelo
;
Lan, Yu-Ching
Objectives It is not known if the incidences of autoimmune diseases are higher in individuals living with HIV infection or AIDS. Our study investigated the incidences of autoimmune diseases among people living with HIV/AIDS (PLWHA) in Taiwan during 2000-2012. Methods The Taiwan National Health Insurance Research Database was used to identify PLWHA. The incidence densities of systemic and organ-specific autoimmune diseases were calculated, and age-adjusted, sex-adjusted and period-adjusted standardised incidence rates (SIRs) were obtained by using two million people from the general population as controls. To examine the effects of highly active antiretroviral therapy (HAART) on the incidence of autoimmune diseases, the incidence densities and SIRs of autoimmune diseases were calculated after stratifying PLWHA by HAART status. Results Of the 20 444 PLWHA identified, the overall mean (SD) age was 30.1 (11.0) years; 67.2% of the subjects received HAART. As compared with the general population, SIRs were higher for incident Sjogren syndrome (SIR= 1.64; 95% CI 1.24 to 2.13), psoriasis (SIR= 2.05; 95% CI 1.67 to 2.48), systemic lupus erythematosus (SLE) (SIR= 2.59; 95% CI 1.53 to 4.09), autoimmune haemolytic anaemia (SIR= 35.06; 95% CI 23.1 to 51.02) and uveitis (SIR= 2.50; 95% CI 2.05 to 3.02), but were lower for incident ankylosing spondyloarthritis (SIR= 0.70; 95% CI 0.48 to 0.99). When the effect of HAART on incident autoimmune diseases was considered, PLWHA who received HAART had higher SIRs for psoriasis, autoimmune haemolytic anaemia and uveitis, but had lower risks of rheumatoid arthritis (RA) and ankylosing spondyloarthritis. In contrast, PLWHA who did not receive HAART had higher SIRs for Sjogren syndrome, psoriasis, RA, SLE, scleroderma, polymyositis, autoimmune haemolytic anaemia and Hashimoto's thyroiditis. Conclusions PLWHA had higher risks of incident Sjogren syndrome, psoriasis, SLE, autoimmune haemolytic anaemia and uveitis.
MicroRNA-224 down-regulates Glycine N-methyltransferase gene expression in Hepatocellular Carcinoma
(2018-08-16)
Hung, Jung-Hsien
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Li, Chung-Hsien
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Yeh, Ching-Hua
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Huang, Pin-Cheng
;
Fang, Cheng-Chieh
Glycine N-methyltransferase (GNMT) is a tumor suppressor for HCC. It is down-regulated in HCC, but the mechanism is not fully understood. MicroRNA-224 (miR-224) acts as an onco-miR in HCC. This study is the first to investigate miR-224 targeting the coding region of GNMT transcript. The GNMT-MT plasmid containing a miR-224 binding site silent mutation of the GNMT coding sequence can escape the suppression of miR-224 in HEK293T cells. Expression of both exogenous and endogenous GNMT was suppressed by miR-224, while miR-224 inhibitor enhanced GNMT expression. miR-224 counteracts the effects of GNMT on the reduction of cell proliferation and tumor growth. The levels of miR-224 and GNMT mRNA showed a significant inverse relationship in tumor specimens from HCC patients. Utilizing CCl4-treated hepatoma cells and mice as a cell damage of inflammatory or liver injury model, we observed that the decreased expression levels of GNMT were accompanied with the elevated expression levels of miR-224 in hepatoma cells and mouse liver. Finally, hepatic AAV-mediated GNMT also reduced CCl4-induced miR-224 expression and liver fibrosis. These results indicated that AAV-mediated GNMT has potential liver protection activity. miR-224 can target the GNMT mRNA coding sequence and plays an important role in GNMT suppression during liver tumorigenesis.