Expression of miR-34a in T-cells infected by human T-lymphotropic virus 1

Varun K. Sharma, Vittoria Raimondi, Katia Ruggero, Cynthia A. Pise-Masison, Ilaria Cavallari, Micol Silic-Benussi, Vincenzo Ciminale, Donna M. D'Agostino

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Human T-lymphotropic virus 1 (HTLV-1) immortalizes T-cells and is the causative agent of adult T-cell leukemia/lymphoma (ATLL). HTLV-1 replication and transformation are governed by multiple interactions between viral regulatory proteins and host cell factors that remain to be fully elucidated. The present study investigated the impact of HTLV-1 infection on the expression of miR-34a, a microRNA whose expression is downregulated in many types of cancer. Results of RT-PCR assays showed that five out of six HTLV-1-positive cell lines expressed higher levels of miR-34a compared to normal PBMC or purified CD4+ T-cells. ATLL cell line ED, which did not express miR-34a, showed methylation of the miR-34a promoter. Newly infected PBMC and samples from 10 ATLL patients also showed a prominent increase in miR-34a expression compared to PBMC controls. The primary miR-34a transcript expressed in infected cell line C91PL contained binding motifs for NF-κB and p53. Pharmacological inhibition of NF-κB with Bay 11-7082 indicated that this pathway contributes to sustain miR-34a levels in infected cells. Treatment of infected cell lines with the p53 activator nutlin-3a resulted in a further increase in miR-34a levels, thus confirming it as a transcriptional target of p53. Nutlin-3a-treated cells showed downregulation of known miR-34a targets including the deacetylase SIRT1, which was accompanied by increased acetylation of p53, a substrate of SIRT1. Transfection of C91PL cells with a miR-34a mimic also led to downregulation of mRNA targets including SIRT1 as well as the pro-apoptotic factor BAX. Unlike nutlin-3a, the miR-34a mimic did not cause cell cycle arrest or reduce cell viability. On the other hand, sequestration of miR-34a with a sponge construct resulted in an increase in death of C91PL cells. These findings provide evidence for a functional role for miR-34a in fine-tuning the expression of target genes that influence the turnover of HTLV-1-infected cells.

Original languageEnglish
Article number832
JournalFrontiers in Microbiology
Volume9
Issue numberMAY
DOIs
Publication statusPublished - May 4 2018

Fingerprint

Human T-lymphotropic virus 1
Adult T Cell Leukemia Lymphoma
T-Lymphocytes
Cell Line
Down-Regulation
Viral Regulatory and Accessory Proteins
Porifera
Virus Diseases
Acetylation
Virus Replication
Cell Cycle Checkpoints
MicroRNAs
Methylation
Transfection
Cell Survival
Cell Death
Pharmacology
Gene Expression
Polymerase Chain Reaction
Messenger RNA

Keywords

  • Adult T-cell leukemia/lymphoma
  • HTLV-1
  • MiR-34a
  • Nutlin-3a
  • P53

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)

Cite this

Expression of miR-34a in T-cells infected by human T-lymphotropic virus 1. / Sharma, Varun K.; Raimondi, Vittoria; Ruggero, Katia; Pise-Masison, Cynthia A.; Cavallari, Ilaria; Silic-Benussi, Micol; Ciminale, Vincenzo; D'Agostino, Donna M.

In: Frontiers in Microbiology, Vol. 9, No. MAY, 832, 04.05.2018.

Research output: Contribution to journalArticle

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