title: Combination of SLC administration and Tregs depletion is an attractive strategy for targeting hepatocellular carcinoma.
abstract: BACKGROUND
  Secondary lymphoid tissue chemokine (SLC) is a key CC chemokine for chemotaxis of immune cells and has been an attractive candidate for anti-tumor treatments. However, among the immune cells recruited by SLC to tumors, the CD25+ Foxp3+ regulatory T cells (Tregs) compromise the anti-tumor effects. In this study, we proposed the combination therapy of intratumoral co-administration of SLC and anti-CD25 monoclonal antibodies (mAbs). We hypothesized that the intratumoral injections of SLC and depletion of Tregs would have stronger inhibition effects on the progression of hepatocellular carcinoma (HCC) in mice.
  
  
  METHODS
  C57BL/6 mice were inoculated subcutaneously with the murine HCC cell line, and mice with visible tumors were treated intratumorally with SLC, SLC plus anti-CD25 mAbs or the control antibodies. The percentages of Tregs, effector CD8+ T cells and CD4+ T cells were checked in the tumors, lymph nodes, spleen and liver at regular intervals. The levels of intratumoral IL-12, IFN-γ, IL-10 and TGF-β1 were evaluated. The final anti-tumor effects were measured by the tumor volume and weight as well as the intratumoral activity of MMP2 and MMP9. Bone-marrow-derived dendritic cells were used to explore the mechanisms of maturation induced by SLC in vitro.
  
  
  RESULTS
  Our experiments showed the combination therapy significantly decreased the frequency of Tregs, and increased CD8+ T cells and CD4+ T cells at tumor sites. These alterations were accompanied by an increased level of IL-12 and IFN-γ, and decreased level of IL-10 and TGF-β1. Unexpectedly, we observed a significantly decreased percentage of Tregs, and increased CD8+ T cells and CD4+ T cells in the lymph nodes, spleen and liver after the combination therapy. The growth and invasiveness of HCC was also maximally inhibited in the combination therapy compared with the SLC alone. Furthermore, we confirmed SLC induced the maturation of DCs via NF-κB p65 and this maturation would benefit the combination therapy.
  
  
  CONCLUSIONS
  Our data demonstrated that intratumoral co-administration of SLC and anti-CD25 mAbs was an effective treatment for HCC, which was correlated with the altered tumor microenvironment and systemically optimized percentages of Tregs, CD8+ T cells and CD4+ T cells in peripheral immune organs.
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Qin
authors.forename: Heng
authors.initials: H
authors.lastname: Hu
authors.forename: Huiying
authors.initials: H
authors.lastname: Ma
authors.forename: Binbin
authors.initials: B
authors.lastname: Liu
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Ma
authors.forename: Shenglong
authors.initials: S
authors.lastname: Ye
authors.forename: Cuiping
authors.initials: C
authors.lastname: Zhong
authors.forename: Guomin
authors.initials: G
authors.lastname: Zhou
authors.affiliation: Principle Investigator of the Lab of Tumor Immunology, the Department of Anatomy and Histology & Embryology, Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032, P R China. cmliang@fudan.edu.cn.
authors.forename: Chunmin
authors.initials: C
authors.lastname: Liang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D006528:Carcinoma, Hepatocellular / Q000276:immunology / Q000628:therapy*; D054421:Chemokine CCL21 / Q000008:administration & dosage*; D003131:Combined Modality Therapy; D003713:Dendritic Cells / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D008099:Liver / Q000276:immunology; D008114:Liver Neoplasms, Experimental / Q000276:immunology / Q000628:therapy*; D008198:Lymph Nodes / Q000276:immunology; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D054400:Receptors, CCR7 / Q000378:metabolism; D013154:Spleen / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C515370:CCR7 protein, human; D054421:Chemokine CCL21; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508609:IL10 protein, human; D054400:Receptors, CCR7; D053773:Transforming Growth Factor beta1; D016753:Interleukin-10; D018664:Interleukin-12; D007371:Interferon-gamma