Methylation Profiling of Epstein-Barr Virus Immediate-early Gene Promoters, BZLF1 and BRLF1 in Tumors of Epithelial, NK- and B-cell Origins
Overview
Affiliations
Background: Epstein-Barr virus (EBV) establishes its latency in EBV-associated malignancies, accompanied by occasionally reactivated lytic cycle. Promoter CpG methylation of EBV genome plays an essential role in maintaining viral latency. Two immediate-early (IE) genes, BZLF1 and BRLF1, induce the switch from latent to lytic infection. Studies of methylation-dependent binding of BZLF1 and BRLF1 to EBV promoters have been well reported, but little is known about the methylation status of BZLF1 and BRLF1 promoters (Zp and Rp) in tumor samples.
Methods: We evaluated the methylation profiles of Zp and Rp by methylation-specific PCR (MSP) and bisulfite genomic sequencing (BGS), as well as BZLF1 and BRLF1 expression by semiquantitative reverse transcription (RT)-PCR in tumors of epithelial, NK- and B-cell origins.
Results: We found that both Zp and Rp were hypermethylated in all studied EBV-positive cell lines and tumors of lymphoid (B- or NK cell) or epithelial origin, while unmethylated Zp and Rp alleles were detected in cell lines expressing BZLF1 and BRLF1. Following azacytidine treatment or combined with trichostatin A (TSA), the expression of BZLF1 and BRLF1 was restored along with concomitant promoter demethylation, which subsequently induced the reactivation of early lytic gene BHRF1 and late lytic gene BLLF1.
Conclusions: Hypermethylation of Zp and Rp mediates the frequent silencing of BZLF1 and BRLF1 in EBV-associated tumors, which could be reactivated by demethylation agent and ultimately initiated the EBV lytic cascade.
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Lupo J, Truffot A, Andreani J, Habib M, Epaulard O, Morand P Viruses. 2023; 15(3).
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Firoz A, Ali H, Rehman S, Rather I Vaccines (Basel). 2022; 10(4).
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Epigenetic control of the Epstein-Barr lifecycle.
Guo R, Gewurz B Curr Opin Virol. 2021; 52:78-88.
PMID: 34891084 PMC: 9112224. DOI: 10.1016/j.coviro.2021.11.013.
Adoptive T-Cell Therapy for Epstein-Barr Virus-Related Lymphomas.
Heslop H, Sharma S, Rooney C J Clin Oncol. 2021; 39(5):514-524.
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Epstein-Barr Virus Promotes B Cell Lymphomas by Manipulating the Host Epigenetic Machinery.
Di Pietro A Cancers (Basel). 2020; 12(10).
PMID: 33086505 PMC: 7603164. DOI: 10.3390/cancers12103037.