Browsing by Subject "Reactivation"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Caspases Switch off the m6A RNA Modification Pathway to Foster the Replication of a Ubiquitous Human Tumor Virus
    (American Society for Microbiology, 2021-08-31) Zhang, Kun; Zhang, Yucheng; Maharjan, Yunash; Sugiokto, Febri Gunawan; Wan, Jun; Li, Renfeng; Medical and Molecular Genetics, School of Medicine
    The methylation of RNA at the N6 position of adenosine (m6A) orchestrates multiple biological processes to control development, differentiation, and cell cycle, as well as various aspects of the virus life cycle. How the m6A RNA modification pathway is regulated to finely tune these processes remains poorly understood. Here, we discovered the m6A reader YTHDF2 as a caspase substrate via proteome-wide prediction, followed by in vitro and in vivo validations. We further demonstrated that cleavage-resistant YTHDF2 blocks, while cleavage-mimicking YTHDF2 fragments promote, the replication of a common human oncogenic virus, Epstein-Barr virus (EBV). Intriguingly, our study revealed a feedback regulation between YTHDF2 and caspase-8 via m6A modification of CASP8 mRNA and YTHDF2 cleavage during EBV replication. Further, we discovered that caspases cleave multiple components within the m6A RNA modification pathway to benefit EBV replication. Our study establishes that caspase disarming of the m6A RNA modification machinery fosters EBV replication.
  • Thumbnail Image
    Item
    Hepatitis B Virus Reactivation in Cancer Patients Receiving Direct-Acting Antivirals for Hepatitis C Virus Infection
    (Wiley, 2021) Pritchard, Haley; Hwang, Jessica P.; Angelidakis, Georgios; Yibirin, Marcel; Wang, Lan; Miller, Ethan; Torres, Harrys A.; Medicine, School of Medicine
    Direct-acting antivirals (DAAs) against hepatitis C virus (HCV) infection can cause hepatitis B virus (HBV) reactivation in HBV/HCV co-infected patients. Cancer patients undergoing immunosuppressant treatment or chemotherapy are at risk for HBV reactivation. To our knowledge, no prospective studies have examined the risk of HBV reactivation during DAA treatment for HCV infection in cancer patients with HBV/HCV co-infection. Here, we report the results of one such study. In a prospective observational study, we enrolled HCV-infected cancer patients undergoing DAA treatment at The University of Texas MD Anderson Cancer Center between January 2015 and March 2018. Data regarding demographics, cancer history, and prior HCV treatment history were collected. Patients were assessed for HBV status before DAA treatment and for HBV-related outcomes, including HBV reactivation, hepatitis flare, and HBV-associated hepatitis, during DAA treatment. Demographic and treatment variables were analyzed using descriptive statistics. One hundred sixty-six patients were analyzed. Forty-eight patients received systemic chemotherapy within 6 months before to 6 months after treatment with DAAs. Ledipasvir plus sofosbuvir was the most common DAA regimen, administered to 88 patients (53%). Fifty-one patients (31%) had past HBV infection, and 4 (2.4%) had chronic HBV infection. No patient experienced HBV reactivation, hepatitis flare, or HBV-associated hepatitis induced by DAA treatment. In HCV-infected cancer patients, DAA treatment is safe regardless of whether patients have past or chronic HBV infection. However, HBV screening is still recommended before the initiation of and during DAA treatment, as is anti-HBV prophylactic treatment in selected cases.