CCL21 promotes the migration and adhesion of highly lymph node metastatic human non-small cell lung cancer Lu-99 in vitro.

To develop new therapy strategies for lung cancer, we established an animal model, which reflects the clinical features of mediastinal lymph node metastasis of lung cancer. This study was designed to determine whether CCL21 induced biological functions associated with the metastasis of highly lymph node metastatic human non-small cell lung cancer (NSCLC) selected by our model. Orthotopic intrapulmonary implantation of human NSCLC (Lu-99 and A549) was performed to analyze the metastatic characteristics of these cells. The expression of CCR7, which is a receptor of CCL21, was detected using CCL19 [also called EBI1-ligand chemokine (ELC)]-Fc chimera by flow cytometric analysis. The effects of CCL21 on the migration, adhesion and growth of human NSCLC were investigated. After orthotopic implantation of human NSCLC cell lines, Lu-99, but not A549, metastasized to mediastinal lymph nodes, forming large size nodules, and expressed CCR7 on the surface. Accordingly, its ligand CCL21 induced chemotactic migration and alpha4beta1-mediated adhesion to VCAM-1 of Lu-99. The expression of CCR7 and vigorous responses to its ligand CCL21 potentially account for lymph node metastasis of a human NSCLC line Lu-99.

RANKL-induced CCL22/macrophage-derived chemokine produced from osteoclasts potentially promotes the bone metastasis of lung cancer expressing its receptor CCR4.

Chemokines are now known to play an important role in cancer growth and metastasis. Here we report that differentiating osteoclasts constitutively produce CCL22 (also called macrophage-derived chemokine) and potentially promote bone metastasis of lung cancer expressing its receptor CCR4. We first examined expression of chemokines by differentiating osteoclasts. CCL22 was selectively upregulated in osteoclast-like cells derived from RAW264.7 cells and mouse bone marrow cells upon stimulation with RANKL (receptor activator of nuclear factor-kappaB ligand). In addition, a human lung cancer cell line SBC-5 that efficiently metastasized to bone when intravenously injected into NK cell-depleted SCID mice was found to express CCR4. Stimulation of SBC-5 cells with CCL22 induced cell migration and also enhanced phosphorylation of protein kinase B/Akt and extracellular signal-regulated kinase (ERK). Furthermore, immunohistochemical analysis of bone metastasis lesions demonstrated close co-localization of tartrate-resistant alkaline phosphatase (TRAP)-positive osteoclasts expressing CCL22 and SBC-5 cells expressing CCR4. Collectively, these results suggest that osteoclasts may promote bone metastasis of cancer cells expressing CCR4 in the bone marrow by producing its ligand CCL22.

Anti-tumor angiogenic effect of a matrix metalloproteinase inhibitor MMI270.

We investigated the anti-angiogenic effects of a matrix metalloproteinase inhibitor, (MMI), so called MMI270, against B16-BL6 melanoma through the inhibition of the migrating and invasive abilities of hepatic sinusoidal endothelial (HSE) cells, as well as the formation of tube-like structures by HSE cells. MMI270, at the concentration of 12.5 micrograms/ml, significantly inhibited the migration and invasion of HSE cells, in addition to tube formation by approximately 40%. Furthermore, the enzymatic degradation of metalloproteinases MMP-9 and MMP-2 produced by HSE cells was inhibited by treatment with 1 microgram/ml of MMI270, showing 30% and 100% of inhibition in comparison to the control, respectively. The intraperitoneal administration of MMI270 (200 mg/kg, twice daily for 8 days) after the implantation of B16-BL6 melanoma cells into mice reduced the number of vessels towards the established primary tumor on the dorsal side of mice. These results suggest that MMI270 might be useful as an anti-tumor angiogenic drug.

Inhibition of lymphangiogenesis-related properties of murine lymphatic endothelial cells and lymph node metastasis of lung cancer by the matrix metalloproteinase inhibitor MMI270.

Based on a previous report on the effect of a matrix metalloproteinase (MMP) inhibitory compound, MMI270, in regulating tumor-induced angiogenesis, as well as recent findings concerning functional correlations among tumor metastasis, angiogenesis and lymphangiogenesis, we investigated the anti-metastatic efficacy of MMI270 in a murine model of lymph node metastasis of lung cancer, and analyzed whether this inhibitor could also regulate lymphangiogenesis-related properties of murine lymphatic endothelial cells (LECs) and invasive properties of Lewis lung cancer (LLC) cells. The observation that MMI270 led to a significant decrease in the weight of tumor-metastasized lymph nodes of mice led us to test its anti-lymphangiogenic and anti-invasive effects in vitro. Murine LECs were characterized by an in vitro tube formation assay, by semi-quantitative RT-PCR assay to examine the expression of mRNAs for flt-4, Flk-1, Tie-1, Tie-2, CD54/ICAM1, vWF, MMPs and uPA, and by western blotting to confirm the protein expression of flt-4 and CD31/PECAM. This is the first report on the expression of MMP-2, MMP-9 and MT1-MMP in murine LECs, as well as on the inhibition of their enzymatic activity, and of the invasive ability and tube-forming property of LECs by an MMP inhibitor. Furthermore, MMI270 was shown to strongly inhibit the activity of MMP-2 and -9 produced by LLC cells and the invasion of these cells through Matrigel. In summary, the present results indicate that MMI270, apart from its anti-tumor angiogenic application, might be useful as an anti-metastatic drug, on the basis of its downregulatation of both the lymphangiogenesis-related properties of LECs and the invasive properties of LLC cells in vitro.