Format

Send to

Choose Destination
Gene. 2007 Dec 15;405(1-2):65-78. Epub 2007 Sep 19.

Direct inhibition of CDK9 blocks HIV-1 replication without preventing T-cell activation in primary human peripheral blood lymphocytes.

Author information

1
Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 North Broad Street, Philadelphia, PA 19140, USA.

Abstract

HIV-1 transcription is essential for the virus replication cycle. HIV-1 Tat is a viral transactivator that strongly stimulates the processivity of RNA polymerase II (RNAPII) via recruitment of the cyclin T1/CDK9 positive transcription elongation factor, which phosphorylates the C-terminal domain (CTD) of RNAPII. Consistently, HIV-1 replication in transformed cells is very sensitive to direct CDK9 inhibition. Thus, CDK9 could be a potential target for anti-HIV-1 therapy. A clearer understanding of the requirements for CDK9 activity in primary human T cells is needed to assess whether the CDK9-dependent step in HIV-1 transcription can be targeted clinically. We have investigated the effects of limiting CDK9 activity with recombinant lentiviruses expressing a dominant-negative form of CDK9 (HA-dnCDK9) in peripheral blood lymphocytes (PBLs) and other cells. Our results show that direct inhibition of CDK9 potently inhibits HIV-1 replication in single-round infection assays with little to undetectable effects on RNAPII transcription, RNA synthesis, proliferation and viability. In PBLs purified from multiple donors, direct inhibition of CDK9 activity blocks HIV-1 replication/transcription but does not prevent T-cell activation, as determined via measurement of cell surface and cell cycle entry and progression markers, and DNA synthesis. We have also compared the effects of HA-dnCDK9 to flavopiridol (FVP), a general CDK inhibitor that potently inhibits CDK9. In contrast to HA-dnCDK9, FVP interferes with key cellular processes at concentrations that inhibit HIV-1 replication with potency similar to HA-dnCDK9. In particular, FVP inhibits several T-cell activation markers and DNA synthesis in primary PBLs at the minimal concentrations required to inhibit HIV-1 replication. Our results imply that small pharmacological compounds targeting CDK9 with enhanced selectivity could be developed into effective anti-HIV-1 therapeutic drugs.

PMID:
17949927
PMCID:
PMC2222555
DOI:
10.1016/j.gene.2007.09.010
[Indexed for MEDLINE]
Free PMC Article

Publication types, MeSH terms, Substances, Grant support

Publication types

MeSH terms

Substances

Grant support

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center