JIBTVA  Vol.1 No.1 , April 2012
Poly-I:C Decreases Dendritic Cell Viability Independent of PKR Activation
ABSTRACT
Vaccination with tumor-antigen pulsed, monocyte-derived dendritic cells (DCs) has emerged as a promising strategy in cancer immunotherapy. The standard DC maturation cocktail consists of a combination of tumor necrosis factor-α (TNF-α)/interleukin (IL)-1β/IL-6 and prostaglandin E2 (PGE2) for generation of standard DCs (sDCs). In order to improve IL-12p70 production and cytotoxic T-lymphocyte (CTL) induction, a novel cocktail composed of TNF-α/IL-1β/ interferon (IFN)-α/IFN-γ and polyinosinic:polycytidylic acid (Poly-I:C) has been introduced to generate so-called α-Type-1 polarized DCs (αDC1s). We and others have previously performed a comprehensive comparison of sDCs and αDC1s. Here we demonstrate that the viability of αDC1s is lowered compared to sDCs and that DC apoptosis is mediated by Poly-I:C. We speculated that activation of protein kinase R (PKR) could mediate the observed apoptosis, but despite significantly higher PKR expression in αDC1s compared to sDCs and induction of active threonine (Thr)446 autophosphorylation of PKR in αDC1s, Poly-I:C did not influence total PKR expression or autophosporylation, indicating PKR-independent Poly-I:C-induced DC apoptosis.

Cite this paper
H. Larsen and A. Pedersen, "Poly-I:C Decreases Dendritic Cell Viability Independent of PKR Activation," Journal of Immune Based Therapies, Vaccines and Antimicrobials, Vol. 1 No. 1, 2012, pp. 1-6. doi: 10.4236/jibtva.2012.11001.
References
[1]   F. Sallusto and A. Lanzavecchia, “Efficient Presentation of Soluble Antigen by Cultured Human Dendritic Cells Is Maintained by Granulocyte/Macrophage Colony-Stimulating Factor plus Interleukin 4 and Downregulated by Tumor Necrosis Factor Alpha,” The Journal of Experimental Medicine, Vol. 179, No. 4, 1994, pp. 1109-1118. doi:10.1084/jem.179.4.1109

[2]   I. J. de Vries, W. J. Lesterhuis, N. M. Scharenborg, L. P. Engelen, D. J. Ruiter, M. J. Gerritsen, et al., “Maturation of Dendritic Cells Is a Prerequisite for Inducing Immune Responses in Advanced Melanoma Patients,” Clinical Cance Research, Vol. 9, 2003, p. 5091.

[3]   H. Jonuleit, U. Kuhn, G. Muller, K. Steinbrink, L. Paragnik, E. Schmitt, et al., “Pro-Inflammatory Cytokines and Prostaglandins Induce Maturation of Potent Immunostimulatory Dendritic Cells under Fetal Calf Serum-Free Conditions,” European Journal of Immunology, Vol. 27, No. 12, 1997, pp. 3135-3142. doi:10.1002/eji.1830271209

[4]   R. Trepiakas, A. E. Pedersen, O. Met, M. H. Hansen, A. Berntsen and I. M. Svane, “Comparison of Alpha-Type-1 Polarizing and Standard Dendritic Cell Cytokine Cocktail for Maturation of Therapeutic Monocyte-Derived Dendritic Cell Preparations from Cancer Patients,” Vaccine, Vol. 26, No. 23, 2008, pp. 2824-2832. doi:10.1016/j.vaccine.2008.03.054

[5]   R. B. Mailliard, A. Wankowicz-Kalinska, Q. Cai, A. Wesa, C. M. Hilkens, M. L. Kapsenberg, et al., “Alpha- Type-1 Polarized Dendritic Cells: A Novel Immunization Tool with Optimized CTL-Inducing Activity,” Cancer Research, Vol. 64, No. 17, 2004, pp. 5934-5937. doi:10.1158/0008-5472.CAN-04-1261

[6]   C. S. McAllister and C. E. Samuel, “The RNA-Activated Protein Kinase Enhances the Induction of Interferon-Beta and Apoptosis Mediated by Cytoplasmic RNA Sensors,” Journal of Biological Chemistry, Vol. 284, No. 3, 2009, pp. 1644-1651. doi:10.1074/jbc.M807888200

[7]   F. Zhang, P. R. Romano, T. Nagamura-Inoue, B. Tian, T. E. Dever, M. B. Mathews, et al., “Binding of Double- Stranded RNA to Protein Kinase PKR Is Required for Dimerization and Promotes Critical Autophosphorylation Events in the Activation Loop,” Journal of Biological Chemistry, Vol. 276, No. 27, 2001, pp. 24946-24958. doi:10.1074/jbc.M102108200

[8]   D. Scheuner, R. Patel, F. Wang, K. Lee, K. Kumar, J. Wu, et al., “Double-Stranded RNA-Dependent Protein Kinase Phosphorylation of the Alpha-Subunit of Eukaryotic Translation Initiation Factor 2 Mediates Apoptosis,” Journal of Biological Chemistry, Vol. 281, No. 30, 2006, pp. 21458-21468. doi:10.1074/jbc.M603784200

[9]   L. Alexopoulou, A. C. Holt, R. Medzhitov and R. A. Flavell, “Recognition of Double-Stranded RNA and Activation of NF-kappa B by Toll-Like Receptor 3,” Nature, Vol. 413, No. 6857, 2001, pp. 732-738. doi:10.1038/35099560

[10]   Z. Jiang, M. Zamanian-Daryoush, H. Nie, A. M. Silva, B. R. Williams and X. Li, “Poly(I-C)-Induced Toll-Like Receptor 3 (TLR3)-Mediated Activation of NFkappa B and MAP Kinase Is through an Interleukin-1 Receptor- Associated Kinase (IRAK)-Independent Pathway Employing the Signaling Components TLR3-TRAF6-TAK1- TAB2-PKR,” Journal of Biological Chemistry, Vol. 278, No. 19, 2003, pp. 16713-16719. doi:10.1074/jbc.M300562200

[11]   A. E. Pedersen, M. Thorn, M. Gad, M. R. Walter, H. E. Johnsen, E. Gaarsdal, et al., “Phenotypic and Functional Characterization of Clinical Grade Dendritic Cells Generated from Patients with Advanced Breast Cancer for Therapeutic Vaccination,” Scandinavian Journal of Immunology, Vol. 61, No. 2, 2005, pp. 147-156. doi:10.1111/j.0300-9475.2005.01531.x

[12]   C. A. Williams, R. A. Harry and J. D. McLeod, “Apoptotic Cells Induce Dendritic Cell-Mediated Suppression via Interferon-Gamma-Induced IDO,” Immunology, Vol. 124, No. 1, 2008, pp. 89-101. doi:10.1111/j.1365-2567.2007.02743.x

[13]   M. A. Garcia, E. F. Meurs and M. Esteban, “The dsRNA Protein Kinase PKR: Virus and Cell Control,” Biochimie, Vol. 89, No. 6-7, 2007, pp. 799-811. doi:10.1016/j.biochi.2007.03.001

 
 
Top