title: [Mechanisms of antimicrobial peptide LL-37 in macrophage-promoted ovarian cancer cell proliferation].
abstract: OBJECTIVE
  The aim of this study was to investigate the role of macrophages in promotion of ovarian tumor cell proliferation mediated by over-expression of antimicrobial peptide LL-37.
  
  
  METHODS
  To co-culture ovarian tumor cells SKOV3, 3AO and HO-8910 with macrophages. The Transwell(®) inserts system was used in the co-culture model. The effect of macrophages promoted ovarian tumor cell proliferation was assessed by BrdU-ELISA and cell number counting. Expressions of mRNA and protein of LL-37 in the macrophages and SKOV3 cells were determined by RT-PCR and Western blot analysis. To observe that LL-37 is responsible for macrophage-promoted ovarian tumor cells growth, LL-37 neutralizing antibody was added to abrogate the LL-37 activation.
  
  
  RESULTS
  The cell number assay showed that after 4 days coincubation with macrophages in the proportion of 1:0.5, the number of SKOV3 cells increased from (6.0 ± 0.5)×10(4) to (11.8 ± 1.3)×10(4), showing a significant difference (P < 0.05). It also showed that the growth of the SKOV3 cells was dependent on the macrophage number (P < 0.05). The number variability of 3AO and HO-8910 cells was as the same as SKOV3 cells upon co-culture with macrophages. As determined by BrdU-ELISA, the resulted proliferation of ovarian tumor cells was similar to the result of cell number counting. RT-PCR and Western blot results showed that the expression of LL-37 mRNA and protein in the macrophages was remarkably enhanced in a time dependent manner upon coincubation with SKOV3 cells, but did not work in SKOV3 cells. BrdU-ELISA assay exhibited that treatment of cells with LL-37 significantly stimulated HO-8910 and 3AO cell proliferation. Addition of LL-37 neutralizing antibody markedly inhibited macrophage-promoted ovarian tumor cell (SKOV3, 3AO and HO-8910 cells) proliferation. The OD values of these three cells were decreased from 2.95 ± 0.11 to 1.45 ± 0.04, from 3.39 ± 0.36 to 1.32 ± 0.09 and from 3.93 ± 0.17 to 1.68 ± 0.23, respectively (P < 0.05).
  
  
  CONCLUSIONS
  Over-expression and release of LL-37 from macrophages is responsible for proliferation of ovarian tumor cells in co-culture condition. The data presented indicate that LL-37 may be critical for macrophage-induced tumor progression.
authors: Department of Clinical Laboratory, Tongji Hospital of Tongji University, Shanghai 200065, China.
authors: Dong
authors: D
authors: Li
authors: Xuan
authors: X
authors: Wang
authors: Yan
authors: Y
authors: Dai
authors: Fan
authors: F
authors: Yang
authors: Email: whysz@163.net.
authors: Hai-ying
authors: HY
authors: Wan
mesh_terms: D057134:Antibodies, Neutralizing / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000502:physiology*; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D057134:Antibodies, Neutralizing; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins; D012333:RNA, Messenger