Mark A. Feitelson
College of Science and Technology
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Featured researches published by Mark A. Feitelson.
PLOS ONE | 2012
Ke Yuan; Zhaorui Lian; Bill N. C. Sun; Marcia M. Clayton; Irene Oi-Lin Ng; Mark A. Feitelson
Hepatitis B virus encoded X antigen (HBx) is a trans-regulatory protein that alters the activity of selected transcription factors and cytoplasmic signal transduction pathways. HBx transcriptionally up-regulates the expression of a unique gene, URG11, which in turn transcriptionally up-regulates β-catenin, thereby contributing importantly to hepatocarcinogenesis. HBx and URG11 also alter the expression of multiple microRNAs, and by miRNA array analysis, both were shown to promote the expression of miR-148a. Elevated miR-148a was also seen in HBx positive liver samples from infected patients. To study the function of miR-148a, anti-148a was introduced into HepG2 and Hep3B cells stably expressing HBx or stably over-expressing URG11. Anti-miR-148a suppressed cell proliferation, cell cycle progression, cell migration, anchorage independent growth in soft agar and subcutaneous tumor formation in SCID mice. Introduction of anti-miR-148a increased PTEN protein and mRNA expression, suggesting that PTEN was targeted by miR-148a. Anti-miR-148a failed to suppress PTEN expression when co-transfected with reporter gene mutants in the 3′UTR of PTEN mRNA. Introduction of anti-miR-148a also resulted in depressed Akt signaling by HBx and URG11, resulting in decreased expression of β-catenin. Thus, miR-148a may play a central role in HBx/URG11 mediated HCC, and may be an early diagnostic marker and/or therapeutic target associated with this tumor type.
Hepatology | 2013
Kyoung-Sub Song; Chang Han; Jinqiang Zhang; Dongdong Lu; Srikanta Dash; Mark A. Feitelson; Kyu Lim; Tong Wu
MicroRNA‐122 (miR‐122), a pivotal liver‐specific miRNA, has been implicated in several liver diseases including hepatocellular carcinoma (HCC) and hepatitis C and B viral infection. This study aimed to explore epigenetic regulation of miR‐122 in human HCC cells and to examine the effect of hepatitis C virus (HCV) and hepatitis B virus (HBV). We performed microRNA microarray analysis and identified miR‐122 as the most up‐regulated miRNA (6‐fold) in human HCC cells treated with 5′aza‐2′deoxycytidine (5‐Aza‐CdR, DNA methylation inhibitor) and 4‐phenylbutyric acid (PBA, histone deacetylation inhibitor). Real‐time polymerase chain reaction (PCR) analysis verified significant up‐regulation of miR‐122 by 5′aza and PBA in HCC cells, and to a lesser extent in primary hepatocytes. Peroxisome proliferator activated receptor‐gamma (PPARγ) and retinoid X receptor alpha (RXRα) complex was found to be associated with the DR1 and DR2 consensus site in the miR‐122 gene promoter which enhanced miR‐122 gene transcription. 5‐Aza‐CdR and PBA treatment increased the association of PPARγ/RXRα, but decreased the association of its corepressors (N‐CoR and SMRT), with the miR‐122 DR1 and DR2 motifs. The aforementioned DNA‐protein complex also contains SUV39H1, an H3K9 histone methyl transferase, which down‐regulates miR‐122 expression. Conclusions: These findings establish a novel role of the PPARγ binding complex for epigenetic regulation of miR‐122 in human HCC cells. Moreover, we show that hepatitis B virus X protein binds PPARγ and inhibits the transcription of miR‐122, whereas hepatitis C viral particles exhibited no significant effect; these findings provide mechanistic insight into reduction of miR‐122 in patients with HBV but not with HCV infection. (Hepatology 2013;58:1681–1692)
Journal of Virology | 2011
Yimin Tong; Yongzhe Zhu; Xueshan Xia; Yuan Liu; Yue Feng; Xian Hua; Zhihui Chen; Hui Ding; Li Gao; Yongzhi Wang; Mark A. Feitelson; Ping Zhao; Qi Zt
ABSTRACT Hepatitis C virus (HCV)-related research has been hampered by the lack of appropriate small-animal models. It has been reported that tree shrews, or tupaias (Tupaia belangeri), can be infected with serum-derived HCV. However, these reports do not firmly establish the tupaia as a reliable model of HCV infection. Human CD81, scavenger receptor class B type I (SR-BI), claudin 1 (CLDN1), and occludin (OCLN) are considered essential receptors or coreceptors for HCV cell entry. In the present study, the roles of these tupaia orthologs in HCV infection were assessed. Both CD81 and SR-BI of tupaia were found to be able to bind with HCV envelope protein 2 (E2). In comparison with human CD81, tupaia CD81 exhibited stronger binding activity with E2 and increased HCV pseudoparticle (HCVpp) cell entry 2-fold. The 293T cells transfected with tupaia CLDN1 became susceptible to HCVpp infection. Moreover, simultaneous transfection of the four tupaia factors into mouse NIH 3T3 cells made the cells susceptible to HCVpp infection. HCVpp of diverse genotypes were able to infect primary tupaia hepatocytes (PTHs), and this infection could be blocked by either anti-CD81 or anti-SR-BI. PTHs could be infected by cell culture-produced HCV (HCVcc) and did produce infectious progeny virus in culture supernatant. These findings indicate that PTHs possess all of the essential factors required for HCV entry and support the complete HCV infection cycle. This highlights both the mechanisms of susceptibility of tupaia to HCV infection and the possibility of using tupaia as a promising small-animal model in HCV study.
Antimicrobial Agents and Chemotherapy | 2013
Guoyi Wu; Bo Liu; Yingjun Zhang; Alla Arzumanyan; Marcia M. Clayton; Raymond F. Schinazi; Zhaohe Wang; Siegfried Goldmann; Qingyun Ren; Faxhou Zhang; Mark A. Feitelson
ABSTRACT Hepatitis B virus (HBV)-associated chronic liver diseases are treated with nucleoside analogs that target the virus polymerase. While these analogs are potent, drugs are needed to target other virus-encoded gene products to better block the virus replication cycle and chronic liver disease. This work further characterized GLS4 and compared it to the related BAY 41-4109, both of which trigger aberrant HBV core particle assembly, where the virus replication cycle occurs. This was done in HepAD38 cells, which replicate HBV to high levels. In vitro, GLS4 was significantly less toxic for primary human hepatocytes (P < 0.01 up to 100 μM), inhibited virus accumulation in the supernantant of HepAD38 cells (P < 0.02 up to 100 nM), inhibited HBV replicative forms in the liver with a significantly lower 50% effective concentration (EC50) (P < 0.02), and more strongly inhibited core gene expression (P < 0.001 at 100 to 200 nM) compared to BAY 41-4109. In vivo characterization was performed in nude mice inoculated with HepAD38 cells, which grew out as tumors, resulting in viremia. Treatment of mice with GLS4 and BAY 41-4109 showed strong and sustained suppression of virus DNA to about the same extents both during and after treatment. Both drugs reduced the levels of intracellular core antigen in the tumors. Alanine aminotransferase levels were normal. Tumor and total body weights were not affected by treatment. Thus, GLS4 was as potent as the prototype, BAY 41-4109, and was superior to lamivudine, in that there was little virus relapse after the end of treatment and no indication of toxicity.
Cancer Letters | 2009
Mark A. Feitelson; Helena M. G. P. V. Reis; N. Lale Tufan; Bill N. C. Sun; Jingbo Pan; Zhaorui Lian
Under most circumstances, hepatitis B virus (HBV) is noncytopathic. However, hepatocellular regeneration that accompanies each bout of hepatitis appears to be associated with increased integration of HBV DNA fragments expressing the virus encoded hepatitis B x antigen (HBxAg). Intrahepatic HBxAg staining correlates with the intensity and progression of chronic liver disease (CLD), and additional work has shown that HBxAg blocks immune mediated killing by Fas and by tumor necrosis factor alpha (TNFalpha). This is not only associated with the blockage of caspase activities by HBxAg, but also by the constitutive stimulation of hepatoprotective pathways, such as nuclear factor kappa B (NF-kappaB), phosphoinositol 3-kinase (PI3K), and beta-catenin (beta-catenin). HBxAg also appears to promote fibrogenesis, by stimulating the production of fibronectin. HBxAg also stimulates the production and activity of transforming growth factor beta1 (TGFbeta1) by several mechanisms, thereby promoting the profibrogenic and tumorigenic properties of this important cytokine. In addition, HBxAg appears to remodel the extracellular matrix (ECM) by altering the expression of several matrix metalloproteinases (MMPs), which may promote tumor metastasis. Hence, HBxAg appears to promote chronic infection by preventing immune mediated apoptosis of infected hepatocytes, by promoting the establishment and persistence of fibrosis and cirrhosis preceding the development of HCC, and by promoting the remodeling of EMC during tumor progression.
Carcinogenesis | 2008
Xiaohong Liu; Li Wang; Shuhui Zhang; Jing Lin; Shunmin Zhang; Mark A. Feitelson; Hengjun Gao; Ming-Hua Zhu
Background: The hepatitis B virus x gene (HBx) is a promiscuous transactivator implicated in the development of hepatocellular carcinoma (HCC). The present study was designed to investigate the molecular events regulated by HBx. Methods: Genomic and proteomic expression profiling was performed in Huh7 HCC cells transfected with HBx mutants with a C-terminal deletion. The gene and protein expression of wingless-type murine-mammary-tumour virus (MMTV) integration site family, member 5A (Wnt-5a) was validated by analyses of reverse transcription–polymerase chain reaction (RT–PCR), real-time RT–PCR, western blot and immunohistochemistry. Results: Differentially expressed genes and proteins were found in the transfected Huh7 HCC cells; most of them were involved in transcriptional regulation, although others including oncogenes or tumor suppressor genes, and molecules involved in cell junctions, signal transduction pathways, metabolism or the immune response were also observed. The expression of the Wnt-5a gene was elevated >10-fold in Huh7 cells transfected with the HBx3′-30 amino acid deletion mutant. However, the expression was downregulated by the transfection with the HBx3′-40 amino acid deletion mutant. The changes in Wnt-5a expression were also observed in human HCC tissues, compared with corresponding non-cancerous liver tissues. A negative correlation was found between the expression of Wnt-5a and HBx COOH mutations in HCC tissues. Conclusions: HBx mutants may participate in the development and progression of HCC, at least in part through the Wnt-5a pathway.
Expert Opinion on Therapeutic Targets | 2014
Mark A. Feitelson; Barbara Bonamassa; Alla Arzumanyan
Introduction: Hepatitis B virus (HBV) is a major cause of chronic liver disease (CLD) and hepatocellular carcinoma (HCC) worldwide. More than 350 million people are at risk for HCC, and with few treatment options available, therapeutic approaches to targets other than the virus polymerase will be needed. This review suggests that the HBV-encoded X protein, HBx, would be an outstanding target because it contributes to the biology and pathogenesis of HBV in three fundamental ways. Areas covered: First, HBx is a trans-activating protein that stimulates virus gene expression and replication, thereby promoting the development and persistence of the carrier state. Second, HBx partially blocks the development of immune responses that would otherwise clear the virus, and protects infected hepatocytes from immune-mediated destruction. Thus, HBx contributes to the development of CLD without virus clearance. Third, HBx alters patterns of host gene expression that make possible the emergence of HCC. The selected literature cited is from the National Library of Medicine (Pubmed and Medline). Expert opinion: Understanding the mechanisms, whereby HBx supports virus replication and promotes pathogenesis, suggests that HBx will be an important therapeutic target against both virus replication and CLD aimed at the chemoprevention of HCC.
Biochemical and Biophysical Research Communications | 2008
Xiaohong Liu; Shuhui Zhang; Jing Lin; Shunmin Zhang; Mark A. Feitelson; Hengjun Gao; Ming-Hua Zhu
The role of the hepatitis B virus X protein (HBx) in hepatocarcinogenesis remains controversial. To investigate the biological impact of hepatitis B virus x gene (HBx) mutation on hepatoma cells, plasmids expressing the full-length HBx or HBx deletion mutants were constructed. The biological activities in these transfectants were analyzed by a series of assays. Results showed that HBx3-20 and HBx3-40 amino acid deletion mutants exhibited an increase in cellular proliferation, focus formation, tumorigenicity, and invasive growth and metastasis through promotion of the cell cycle from G0/G1 to the S phase, when compared with the full-length HBx. In contrast, HBx3-30 amino acid deletion mutant repressed cell proliferation by blocking in G1 phase. The expression of P53, p21(WAF1), p14(ARF), and MDM2 proteins was regulated by expression of HBx mutants. In conclusions, HBx variants showed different effects and functions on cell proliferation and invasion by regulation of the cell cycle progression and its associated proteins expression.
Archive | 2009
Hie-Won L. Hann; Mark A. Feitelson
Hepatocellular carcinoma (HCC) is one of the most common malignant neoplasms in the world. Current data indicate that hepatitis B virus (HBV) and hepatitis C virus (HCV) are the most significant hepatocarcinogens for the majority of HCCs in the world. Globally about 80% of HCC is considered to be causally associated with chronic infection with HBV. Although HCC is rare in the United States, it is perhaps the most prevalent cancer in Asia and West Africa where the prevalence of HBV infection is high. Without proper intervention for HBV infection, the HBV carriers are at risk for developing HCC. In a large prospective study of 3,653 HBV carriers in Taiwan, 164 persons developed HCC in a 12-year follow-up period; the most important risk factors for HCC were increased baseline and persistently elevated HBV DNA levels. During the last decade, great strides have been made in the treatment of HBV infection. Prospective and retrospective studies of large numbers of chronic hepatitis B patients with advanced liver disease have demonstrated that the treatment with anti-HBV agent not only delayed the disease progression but also reduced the incidence of HCC.
Cancer Biomarkers | 2012
Wen Wang; Lan-Juan Zhao; Yan Wang; Qing-Yuan Tao; Mark A. Feitelson; Ping Zhao; Hao Ren; Qi Zt
BACKGROUNDnHepatitis B virus (HBV) carriers are at high risk for the development of hepatocellular carcinoma (HCC), but there are no reliable markers that will identify such high-risk patients. HBV up-regulates the expression of selected genes (URGs) in the liver during chronic infection. These aberrantly expressed proteins trigger corresponding antibodies (anti-URGs) that appear prior to the detection of HCC. This study was undertaken to see if the anti-URGs could be used as early warning biomarker of HBV-induced liver cirrhosis and HCC.nnnMETHODSnA cross sectional study using a total of 625 serum samples from HBV infected and uninfected controls were tested for the anti-URGs using specific ELISAs.nnnRESULTSnThe number and specificity of anti-URGs correlated with the severity of liver disease Anti-URGs were predominantly present among patients with HBV-associated HCC (55.2%) and cirrhosis (60.7%), and at a lower frequency among patients with chronic hepatitis (35.8%), and at still lower frequencies in most asymptomatic carriers (12.3%) with normal ALT, among patients with chronic hepatitis C (38.5%) and blood donors (0.9%). These anti-URGs were rarely detected in sera from those with tumors other than HCC, except among HBV infected patients with cholangioicarcinoma and in some patients with drug induced hepatitis. 3 or more anti-URGs could precede the diagnosis of cirrhosis or HCC 11.8 months on average, and HBV hepatitis patients with 3 or more anti-URGs have much higher risk (5/20 vs 0/30) to develop cirrhosis and HCC than those patients with less anti-URGs. As the early warning biomarker, 3 or more anti-URGs were served as the threshold to separate the cirrhosis and HCC from others with a moderate sensitivity (58.3%) and specificity (80.0%), which was better than other biomarkers (AFP, AFP-L3, GPC3 and GP73) and would improve up to 70.3% when combined with another biomarker.nnnCONCLUSIONSnThe results of this clinical validation study suggest that the anti-URGs might have diagnostic/prognostic utility among patients at high risk for the development of cirrhosis and HCC.