CCL21/CCR7 prevents apoptosis via the ERK pathway in human non-small cell lung cancer cells

PLoS One. 2012;7(3):e33262. doi: 10.1371/journal.pone.0033262. Epub 2012 Mar 16.

Abstract

Previously, we confirmed that C-C chemokine receptor 7 (CCR7) promotes cell proliferation via the extracellular signal-regulated kinase (ERK) pathway, but its role in apoptosis of non-small cell lung cancer (NSCLC) cell lines remains unknown. A549 and H460 cells of NSCLC were used to examine the effect of CCL21/CCR7 on apoptosis using flow cytometry. The results showed that activation of CCR7 by its specific ligand, exogenous chemokine ligand 21 (CCL21), was associated with a significant decline in the percent of apoptosis. Western blot and real-time PCR assays indicated that activation of CCR7 significantly caused upregulation of anti-apoptotic bcl-2 and downregulation of pro-apoptotic bax and caspase-3, but not p53, at both protein and mRNA levels. CCR7 small interfering RNA significantly attenuated these effects of exogenous CCL21. Besides, PD98059, a selective inhibitor of MEK that disrupts the activation of downstream ERK, significantly abolished these effects of CCL21/CCR7. Coimmunoprecipitation further confirmed that there was an interaction between p-ERK and bcl-2, bax, or caspase-3, particularly in the presence of CCL21. These results strongly suggest that CCL21/CCR7 prevents apoptosis by upregulating the expression of bcl-2 and by downregulating the expression of bax and caspase-3 potentially via the ERK pathway in A549 and H460 cells of NSCLC.

MeSH terms

  • Apoptosis / drug effects
  • Apoptosis / physiology
  • Base Sequence
  • Carcinoma, Non-Small-Cell Lung / genetics
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Carcinoma, Non-Small-Cell Lung / pathology*
  • Caspase 3 / genetics
  • Caspase 3 / metabolism
  • Cell Line, Tumor
  • Chemokine CCL21 / metabolism*
  • Chemokine CCL21 / pharmacology
  • Down-Regulation
  • Genes, bcl-2
  • Humans
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology*
  • MAP Kinase Signaling System / drug effects
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Neoplasm / genetics
  • RNA, Neoplasm / metabolism
  • RNA, Small Interfering / genetics
  • Receptors, CCR7 / antagonists & inhibitors
  • Receptors, CCR7 / genetics
  • Receptors, CCR7 / metabolism*
  • Up-Regulation
  • bcl-2-Associated X Protein / genetics
  • bcl-2-Associated X Protein / metabolism

Substances

  • BAX protein, human
  • CCL21 protein, human
  • CCR7 protein, human
  • Chemokine CCL21
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • RNA, Neoplasm
  • RNA, Small Interfering
  • Receptors, CCR7
  • bcl-2-Associated X Protein
  • CASP3 protein, human
  • Caspase 3