title: [Type I collagen secreted by lung cancer cells promotes cancer cell growth in a three- dimensional culture system].
abstract: OBJECTIVE
  To investigate the role of type I collagen as an autocrine protein in promoting the growth lung cancer cells in a three-dimensional (3D) culture system.
  
  
  METHODS
  Immunohistochemistry and RT-PCR were used to detect the expression of type I collagen in lung cancer specimens and 5 lung cancer cell lines. The lung cancer cell lines in 3D cultures were treated with vectors harboring short hairpin RNA (shRNA) targeting type I collagen, and the cell growth suppression was evaluated using MTT assay and colony formation assay. The lung cancer cells stimulated with supernatant from lung cancer-derived fibroblasts were tested for the expression of type I collagen mRNA.
  
  
  RESULTS
  Type I collagen expressions were detected in both the lung cancer tissues and the cell lines. In the 3D culture system, the growth of the cancer cell lines was obviously suppressed by shRNA-mediated type I collagen knockdown evidenced by lowered cell growth rate and colony formation ability. Stimulation with fibroblast culture supernatant resulted in enhanced expressions of type I collagen in the cancer cell lines.
  
  
  CONCLUSIONS
  Autocrine of type I collagen I is required for maintaining lung cancer cell growth in 3D cultures, and its expression is regulated by fibroblasts. These findings provide new insights into the role of type I collagen I in the tumor microenvironment and point a new direction for targeted therapy of tumors.
authors.affiliation: Vascular Biology Research Institute, Guangdong Pharmaceutical University, Guangzhou 510006, China.E-mail: lijiangchao@gdpu.edu.cn.
authors.forename: Jiangchao
authors.initials: J
authors.lastname: Li
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Li
authors.forename: Tian
authors.initials: T
authors.lastname: Lan
authors.forename: Cuiling
authors.initials: C
authors.lastname: Qi
authors.forename: Xiaodong
authors.initials: X
authors.lastname: He
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Lijing
authors.initials: L
authors.lastname: Wang
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Guan
mesh_terms: D002453:Cell Cycle; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D024042:Collagen Type I / Q000378:metabolism*; D005347:Fibroblasts; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger; D034741:RNA, Small Interfering
chemical_list: D024042:Collagen Type I; D012333:RNA, Messenger; D034741:RNA, Small Interfering