Analysis of protein kinase C theta inhibitors for the control of HIV-1 replication in human CD4+ T cells reveals an effect on retrotranscription in addition to viral transcription

Biochem Pharmacol. 2015 Apr 15;94(4):241-56. doi: 10.1016/j.bcp.2015.02.009. Epub 2015 Feb 27.


HIV-1 infection cannot be cured due to reservoirs formed early after infection. Decreasing the massive CD4+ T cell activation that occurs at the beginning of the disease would delay reservoir seeding, providing a better prognosis for patients. CD4+ T cell activation is mediated by protein kinase C (PKC) theta (θ), which is involved in T-cell proliferation, as well as NF-κB, NF-AT, and AP-1 activation. We found that PKCθ activity increased viral replication, but also that HIV-1 induced higher activation of PKCθ in infected CD4+ T cells, creating a feedback loop. Therefore, specific inhibition of PKCθ activity could contribute to control HIV-1 replication. We tested the efficacy of seven PKCθ specific inhibitors to control HIV-1 replication in CD4+ T cells and selected two of the more potent and safer: CGX1079 and CGX0471. They reduced PKCθ phosphorylation at T538 and its translocation to the plasma membrane, which correlated with decreased HIV-1 retrotranscription through partial inhibition of SAMHD1 antiviral activity, rendering lower proviral integration. CGX1079 and CGX0471 also interfered with viral transcription, which would reduce the production of new virions, as well as the subsequent spread and infection of new targets that would increase the reservoir size. CGX1079 and CGX0471 did not completely abrogate T-cell functions such as proliferation and CD8-mediated release of IFN-γ in PBMCs from HIV-infected patients, thereby avoiding general immunosuppresion. Consequently, using PKCθ inhibitors as adjuvant of antiretroviral therapy in recently infected patients would decrease the pool of activated CD4+ T cells, thwarting proviral integration and reducing the reservoir size.

Keywords: Antiretroviral therapy; HIV-1; Latent reservoir; Protein kinase C theta; SAMHD1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-HIV Agents / pharmacology*
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / drug effects*
  • CD4-Positive T-Lymphocytes / virology
  • Cell Membrane / metabolism
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • HIV-1 / drug effects*
  • HIV-1 / genetics
  • HIV-1 / physiology
  • Humans
  • Isoenzymes / antagonists & inhibitors*
  • Jurkat Cells
  • Monomeric GTP-Binding Proteins / metabolism
  • Phosphorylation
  • Protein Kinase C / antagonists & inhibitors*
  • Protein Kinase C-theta
  • Protein Transport
  • Retroelements*
  • SAM Domain and HD Domain-Containing Protein 1
  • Transcription, Genetic
  • Virus Integration / drug effects
  • Virus Internalization
  • Virus Replication


  • Anti-HIV Agents
  • Isoenzymes
  • Retroelements
  • PRKCQ protein, human
  • Protein Kinase C
  • Protein Kinase C-theta
  • SAM Domain and HD Domain-Containing Protein 1
  • SAMHD1 protein, human
  • Monomeric GTP-Binding Proteins