title: Significance of cancer-associated fibroblasts in the regulation of gene expression in the leading cells of invasive lung cancer.
abstract: OBJECTIVE
  Cancer-associated fibroblasts (CAFs) contribute to tumor progression through multiple pathways. However, the effect of CAFs on gene expression in lung cancer has been largely unknown. Here we systematically compared the gene expression changes in lung cancer cells induced by normal fibroblasts and CAFs.
  
  
  METHODS
  Wound healing and cell proliferation assays were used to identify the property of CAFs used in this study. We used cDNA microarray analysis to compare gene expression in lung cancer cells cultured with either conditioned medium (CM) from lung CAFs or normal lung fibroblasts, the result of which was confirmed by RT-PCR and Western blot analysis. Immunohistochemistry on tissue sections from lung cancers was conducted to further confirm the results of cDNA microarray analysis.
  
  
  RESULTS
  The expression of many genes was upregulated in cancer cells by CAF CM, particularly cell adhesion molecules, integrins, and anti-apoptotic protein Bcl-2. Expression of integrins appeared to be upstream from Bcl-2. We identified transforming growth factor-β as a candidate factor that induced the expression of those genes in cancer cells. Immunohistochemical studies of clinical lung cancer tissues revealed that integrins and Bcl-2 were more highly expressed in the leading cells (LCs) than in the following cells, at the invasive front of cancer nests, which are adjacent to or in proximity to the stroma. Furthermore, the expression of integrins and Bcl-2 in LCs had a tendency to correlate with the clinical stage of cancer progression, including lymph node metastasis.
  
  
  CONCLUSIONS
  Our results suggest that CAFs promote lung cancer progression partly through the direct regulation of gene expression in the LCs of invasive cancer nests.
authors.affiliation: Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: An
authors.forename: Atsushi
authors.initials: A
authors.lastname: Enomoto
authors.forename: Liang
authors.initials: L
authors.lastname: Weng
authors.forename: Takuya
authors.initials: T
authors.lastname: Kato
authors.forename: Akari
authors.initials: A
authors.lastname: Iwakoshi
authors.forename: Kaori
authors.initials: K
authors.lastname: Ushida
authors.forename: Keiko
authors.initials: K
authors.lastname: Maeda
authors.forename: Maki
authors.initials: M
authors.lastname: Ishida-Takagishi
authors.forename: Genichiro
authors.initials: G
authors.lastname: Ishii
authors.forename: Shuhong
authors.initials: S
authors.lastname: Ming
authors.forename: Tieying
authors.initials: T
authors.lastname: Sun
authors.forename: Masahide
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology* / Q000502:physiology*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D019254:Genes, bcl-2; D006801:Humans; D016023:Integrins / Q000235:genetics / Q000378:metabolism; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D046228:Microarray Analysis; D009361:Neoplasm Invasiveness; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D055153:Stem Cell Niche / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D016023:Integrins; D016212:Transforming Growth Factor beta