1-MT enhances potency of tumor cell lysate-pulsed dendritic cells against pancreatic adenocarcinoma by downregulating the percentage of tregs

Abstract

This study examined whether 1-methyl-tryptophan [1-MT, an indoleamine 2, 3-dioxygenase (IDO) inhibitor] could reduce CD4⁺CD25⁺ regulatory T cells (Tregs) proliferation and improve the anti-tumor efficacy of dendritic cells (DCs) pulsed with tumor cell lysate in the mice bearing pancreatic adenocarcinoma. The models of pancreatic adenocarcinoma were established in C57BL/6 mice by subcutaneous injection of Pan02 cells. Eight mice which were subcutaneously injected with PBS served as control. The expression of IDO was determined in tumor draining lymph nodes (TDLNs) and spleens of the murine pancreatic adenocarcinoma models. The prevalence of Tregs was measured in the TDLNs and spleens before and after 1-MT administration. The dendritic cells were pulsed with tumor cell lysate for preparing DC vaccine. The DC vaccine, as a single agent or in combination with 1-MT, was administered to pancreatic adenocarcinoma mice. The anti-tumor efficacy was determined after different treatments by regular observation of tumor size. The results showed that the levels of IDO mRNA and protein in tumor-bearing mice were significantly higher than those in the normal control mice. The percentage of Tregs in the spleen and TDLNs was also higer in tumor-bearing mice than in normal control mice (P<0.05). Foxp3 expression was significantly lower in the TDLNs and spleens of tumor-bearing mice administrated with 1-MT than that in normal control mice. Furthemore, in the mice that were administered 1-MT plus DC vaccine, the tumor was increased more slowly than in mice treated with DC vaccine or 1-MT alone, or PBS on day 36 (P<0.01). Our results indicated that 1-MT may enhance anti-tumor efficacy of dendritic cells pulsed with tumor cell lysate by downregulating the percentage of Tregs.

Keywords

1-methyl-tryptophan / Treg cells / pancreatic adenocarcinoma / indoleamine 2, 3-dioxygenase / Foxp3

References

[1] ItohK., YamadaA., MineT., et al.. Recent advances in cancer vaccines: an overview. Jpn J Clin Oncol, 2009, 39(2): 73-80

[2] GilboaE.. DC-based cancer vaccines. J Clin Invest, 2007, 117(5): 1195-203

[3] SchadendorfD., UgurelS., Schuler-ThurnerB., et al.. Dacarbazine (DTIC) versus vaccination with autologous peptide-pulsed dendritic cells (DC) in first-line treatment of patients with metastatic melanoma: a randomized phase III trial of the DC study group of the DeCOG. Ann Oncol, 2006, 17(4): 563-570

[4] QiuJ., LiG.W., SuiY.F., et al.. Heat-shocked tumor cell lysate-pulsed dendritic cells induce effective anti-tumor immune response in vivo. World J Gastroenterol, 2006, 12(3): 473-478

[5] OhshitaA., YamaguchiY., MinamiK., et al.. Generation of tumor-reactive effect or lymphocytes using tumor RNA-introduced dendritic cells in gastric cancer patients. Int J Oncol, 2006, 28(5): 1163-1171

[6] DohnalA.M., GraffiS., WittV., et al.. Comparative evaluation of techniques for the manufacturing of dendritic cell-based cancer vaccines. J Cell Mol Med, 2009, 13(1): 125-135

[7] OhS.T., KimC.H., ParkM.Y., et al.. Dendritic cells transduced with recombinant adenoviruses induce more efficient anti-tumor immunity than dendritic cells pulsed with peptide. Vaccine, 2006, 24(15): 2860-2868

[8] DavidJ., BettingaX.M., KafiaK., et al.. Enhanced immune stimulation by a therapeutic lymphoma tumor antigen vaccine produced in insect cells involves mannose receptor targeting to antigen presenting cells. Vaccine, 2009, 27: 250-259

[9] LiuX.Q., WangX.. Indoleamine 2,3-dioxygenase in tumor induced tolerance. Chin Med J (Engl), 2009, 122(24): 3072-3027

[10] LobS., KonigsrainerA.. Is IDO a key enzyme bridging the gap between tumor escape and tolerance induction?. Langenbecks Arch Surg, 2008, 393(6): 995-1003

[11] Sakaguchi, WingK., OnishiY., et al.. Regulatory T cells: how do they suppress immune responses?. Int Immunol, 2009, 21(10): 1105-1111

[12] MunnD.H., ZhouM., AttwoodJ.T., et al.. Prevention of allogeneic fetal rejection by tryptophan catabolism. Science, 1998, 281(5380): 1191-1193

[13] HayashiT., BeckL., RossettoC., et al.. Inhibition of experimental asthma by indoleamine 2,3-dioxygenase. J Clin Invest, 2004, 114(2): 270-279

[14] KwidzinskiE., BunseJ., AktasO., et al.. Indolamine 2,3-dioxygenase is expressed in the CNS and down-regulates autoimmune inflammation. FASEB J, 2005, 19(10): 1347-1349

[15] GrohmannU., OrabonaC., FallarinoF., et al.. CTLA-4-Ig regulates tryptophan catabolism in vivo. Nat Immunol, 2002, 3(11): 1097-1101

[16] YuG., FangM., GongM., et al.. Steady state dendritic cells with forced IDO expression induce skin allograft tolerance by upregulation of regulatory T cells. Transpl Immunol, 2008, 18(3): 208-219

[17] MellorA.L.. Munn DH. IDO expression by dendritic cells: tolerance and tryptophan catabolism. Nat Rev Immunol, 2004, 4(10): 762-774

[18] GrohmannU., FallarinoF., PuccettiP.. Tolerance, DCs and tryptophan: much ado about IDO. Trends Immunol, 2003, 24(5): 242-248

[19] PuccettiP., FallarinoF.. Generation of T cell regulatory activity by plasmacytoid dendritic cells and tryptophan catabolism. Blood Cells Mol Dis, 2008, 40(1): 101-105

[20] BelladonnaM.L., OrabonaC., GrohmannU., et al.. TGF-beta and kynurenines as the key to infectious tolerance. Trends Mol Med, 2009, 15(2): 41-49

[21] DannullJ., SuZ., RizzieriD., et al.. Enhancement of vaccine-mediated antitumor immunity in cancer patients after depletion of regulatory T cells. J Clin Invest, 2005, 115(12): 3623-3633

[22] WilczynskiJ.R., RadwanM., KalinkaJ.. The characterization and role of regulatory T cells in immune reactions. Front Biosci, 2008, 13: 2266-2274

[23] Moo-YoungT.A., LarsonJ.W., BeltB.A., et al.. Tumor-derived TGF-beta mediates conversion of CD4+Foxp3+ regulatory T cells in a murine model of pancreas cancer. J Immunother, 2009, 32(1): 12-21

[24] AnderssonJ, TranDQ, PesuM, et al.. CD4+FoxP3+ regulatory T cells confer infectious tolerance in a TGF-ta-dependent manner. J Exp Med, 2008, 205(9): 1975-1981

[25] LiuY., ZhangP., LiJ., et al.. A critical function for TGF-[beta] signaling in the development of natural CD4⁺CD25⁺Foxp3⁺ regulatory T cells. Nat Immunol, 2008, 9(6): 632

[26] HuberS, StahlFR, SchraderJ, et al.. Activin a promotes the TGF-ta-induced conversion of CD4+CD25− T cells into Foxp3+ induced regulatory T cells. J Immunol, 2009, 182(8): 4633-4640

[27] BelladonnaML, VolpiC, BianchiR, et al.. Cutting edge: Autocrine TGF-ta sustains default tolerogenesis by IDO-competent dendritic cells. J Immunol, 2008, 181(8): 5194-5198

[28] OuX., CaiS., LiuP., et al.. Enhancement of dendritic cell-tumor fusion vaccine potency by indoleaminepyrrole 2,3-dioxygenase inhibitor, 1-MT. J Cancer Res Clin Oncol, 2008, 134: 525-533

[29] FallarinoF., GrohmannU., YouS., et al.. The combined effects of tryptophan starvation and tryptophan catabolites down-regulate T cell receptor zeta-chain and induce a regulatory phenotype in naive T cells. J Immunol, 2006, 176(11): 6752-6761

[30] SharmaM.D., BabanB., ChandlerP., et al.. Plasmacytoid dendritic cells from mouse tumor-draining lymph nodes directly activate mature Tregs via indoleamine ioxygenase. J Clin Invest, 2007, 117(9): 2570-2582

[31] ZiskeC., EtzrodtP.E., EliuA.S., et al.. Increase of in vivo antitumoral activity by CD40l (CD154) gene transfer into pancreatic tumor cell-dendritic cell hybrids. Pancreas, 2009, 38(10): 758-765