title: CCL21/CCR7 promotes G2/M phase progression via the ERK pathway in human non-small cell lung cancer cells.
abstract: C-C chemokine receptor 7 (CCR7) contributes to the survival of certain cancer cell lines, but its role in the proliferation of human non-small cell lung cancer (NSCLC) cells remains vague. Proliferation assays performed on A549 and H460 NSCLC cells using Cell Counting Kit-8 indicated that activation of CCR7 by its specific ligand, exogenous chemokine ligand 21 (CCL21), was associated with a significant linear increase in cell proliferation with duration of exposure to CCL21. The CCL21/CCR7 interaction significantly increased the fraction of cells in the G(2)/M phase of the cell cycle as measured by flow cytometry. In contrast, CCL21/CCR7 had no significant influence on the G(0)/G(1) and S phases. Western blot and real-time PCR indicated that CCL21/CCR7 significantly upregulated expression of cyclin A, cyclin B1, and cyclin-dependent kinase 1 (CDK1), which are related to the G(2)/M phase transition. The expression of cyclin D1 and cyclin E, which are related to the G(0)/G(1) and G(1)/S transitions, was not altered. The CCL21/CCR7 interaction significantly enhanced phosphorylation of extracellular signal-regulated kinase (P-ERK) but not Akt, as measured by Western blot. LY294002, a selective inhibitor of PI3K that prevents activation of the downstream Akt, did not weaken the effect of CCL21/CCR7 on P-ERK. Coimmunoprecipitation further confirmed that there was an interaction between P-ERK and cyclin A, cyclin B1, or CDK1, particularly in the presence of CCL21. CCR7 small interfering RNA or PD98059, a selective inhibitor of MEK that disrupts the activation of downstream ERK, significantly abolished the effects of exogenous CCL21. These results suggest that CCL21/CCR7 contributes to the time-dependent proliferation of human NSCLC cells by upregulating cyclin A, cyclin B1, and CDK1 potentially via the ERK pathway.
authors.affiliation: Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.forename: Lifeng
authors.initials: L
authors.lastname: Liu
authors.forename: Xueshan
authors.initials: X
authors.lastname: Qiu
authors.forename: Lili
authors.initials: L
authors.lastname: Jiang
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
authors.forename: Haiying
authors.initials: H
authors.lastname: Li
authors.forename: Zixuan
authors.initials: Z
authors.lastname: Li
authors.forename: Wenting
authors.initials: W
authors.lastname: Luo
authors.forename: Enhua
authors.initials: E
authors.lastname: Wang
mesh_terms: D001483:Base Sequence; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D045744:Cell Line, Tumor; D054421:Chemokine CCL21 / Q000502:physiology*; D016195:G2 Phase; D006801:Humans; D047468:Immunoprecipitation; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering; D054400:Receptors, CCR7 / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C515478:CCL21 protein, human; C515370:CCR7 protein, human; D054421:Chemokine CCL21; D034741:RNA, Small Interfering; D054400:Receptors, CCR7