title: The crosstalk: Tumor-infiltrating lymphocytes rich in regulatory T cells suppressed cancer-associated fibroblasts.
abstract: BACKGROUND
  The interactions between cancer-associated fibroblasts (CAFs) and cancer cells or tumor-infiltrating lymphocytes (TILs) and cancer cells play important roles in cancer progression and metastasis. However, studies related to the crosstalk between CAFs and TILs in tumor microenvironment (TME) are still lacking. In this study, we mainly investigated the interactions between CAFs and TILs.
  
  
  METHODS
  The distribution of TILs rich in regulatory T cells (Tregs) in breast cancer tissues was evaluated using hematoxylin-eosin staining and immunohistochemistry with anti-CD3, anti-Foxp3, and anti-α-smooth muscle actin antibodies. Homologous CAFs/normal fibroblasts (NFs) and TILs cultured in vitro were identified and detected using immunocytochemistry and flow cytometry (FCM). The direct interaction among these cell types was studied via a factorial design in a co-cultured system. Their indirect interaction was assayed using Transwell plates. The cell cycle and apoptosis of CAFs/NFs co-cultured with TILs was analyzed using propidium iodide staining.
  
  
  RESULTS
  Histochemistry demonstrated most of the TILs including Tregs, were distributed in the cancer stroma, adjoining to CAFs. This finding implies that both cell types interact closely in the TME. Identification of the cultured cells showed that CAFs maintained their activated phenotype within limited passages in vitro, and that the TILs population contained a high percentage of Tregs. Data analysis of the factorial design suggests significant interactions among CAFs, NFs, and TILs in both direct and indirect contact ways. The CAFs and NFs were suppressed signally by TILs, which are probably induced by the secretory cytokines derived from TILs or Tregs. Although apoptosis was not detected in CAFs/NFs, the cell cycle assay suggested that the CAFs/NFs were arrested in the G2/M phase by the TILs and their secretory cytokines.
  
  
  CONCLUSIONS
  CAFs and NFs were dramatically suppressed by Tregs-rich TILs. This suggests the interaction between TILs and CAFs might modify the TME in an unknown manner.
authors: Key Laboratory of Cancer Prevention and Intervention, the Second Affiliated Hospital, School of Medicine, Zhejiang University , Hangzhou, Zhejiang , P.R. China.
authors: Zhixuan
authors: Z
authors: Fu
authors: Yong
authors: Y
authors: Zuo
authors: Dongbo
authors: D
authors: Li
authors: Wenhong
authors: W
authors: Xu
authors: Dan
authors: D
authors: Li
authors: Huarong
authors: H
authors: Chen
authors: Shu
authors: S
authors: Zheng
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D001940:Breast / Q000276:immunology* / Q000473:pathology; D001943:Breast Neoplasms / Q000276:immunology* / Q000473:pathology; D016022:Case-Control Studies; D002450:Cell Communication; D002453:Cell Cycle; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D018226:Fibroadenoma / Q000276:immunology* / Q000473:pathology; D005347:Fibroblasts / Q000276:immunology* / Q000473:pathology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000473:pathology; D017154:Stromal Cells / Q000276:immunology / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000473:pathology