Autocrine GM-CSF transcription in the leukemic progenitor cell line KG1a is mediated by the transcription factor ETS1 and is negatively regulated through SECTM1 mediated ligation of CD7

ADAM17-regulated CX3CL1 expression produced by bone marrow endothelial cells promotes spinal metastasis from hepatocellular carcinoma

Spinal metastasis occurs in 50-75% of bone metastases caused by hepatocellular carcinoma (HCC), and HCC-derived spinal metastasis can lead to a less favorable prognosis. Recently, several studies have demonstrated that C-X3-C motif chemokine ligand 1 (CX3CL1) is closely associated with cancer metastasis, and its secretion is modulated by a disintegrin and metalloproteinase 17 (ADAM17). Bone marrow endothelial cells (BMECs) are an essential component of bone marrow. However, little is known about the roles in and effects of BMECs on HCC spinal metastasis. The present study demonstrated that CX3CL1 and C-X-C motif chemokine receptor 3 (CXCR3) expression was upregulated in HCC spinal metastases, and that CX3CL1 promoted the migration and invasion of HCC cells to the spine. Western blot analysis revealed that the Src/protein tyrosine kinase 2 (PTK2) axis participated in CX3CL1-induced HCC cell invasion and migration. CX3CL1 also increased the expression of M2 macrophage markers in THP-1 monocytes. BMECs promoted the migration and invasion of Hep3B and MHCC97H cells by secreting soluble CX3CL1, whereas the neutralization of CX3CL1 inhibited this enhancement. CX3CL1 enhanced the activation of the phosphatidylinositol-4,5-bisphos-phate 3-kinase catalytic subunit alpha (PIK3CA)/AKT serine/threonine kinase 1 (AKT1) and Ras homolog family member A (RHOA)/Rho associated coiled-coil containing protein kinase 2 (ROCK2) signaling pathways through the Src/PTK2 signaling pathway. Furthermore, ADAM17 was activated by mitogen-activated protein kinase (MAPK) z14 in BMECs and significantly promoted the secretion of CX3CL1. HCC cells enhanced the recruitment and proliferation of BMECs. The overexpression of CX3CR1 facilitated the spinal metastasis of HCC in a mouse model in vivo. In addition, in vivo experiments revealed that BMECs promoted the growth of HCC in the spine. The present study demonstrated that CX3CL1 participates in HCC spinal metastasis, and that BMECs play an important role in the regulation of CX3CL1 in the spinal metastatic environment.

Epithelial Cell-Derived Secreted and Transmembrane 1a Signals to Activated Neutrophils during Pneumococcal Pneumonia

Airway epithelial cell responses are critical to the outcome of lung infection. In this study, we aimed to identify unique contributions of epithelial cells during lung infection. To differentiate genes induced selectively in epithelial cells during pneumonia, we compared genome-wide expression profiles from three sorted cell populations: epithelial cells from uninfected mouse lungs, epithelial cells from mouse lungs with pneumococcal pneumonia, and nonepithelial cells from those same infected lungs. Of 1,166 transcripts that were more abundant in epithelial cells from infected lungs compared with nonepithelial cells from the same lungs or from epithelial cells of uninfected lungs, 32 genes were identified as highly expressed secreted products. Especially strong signals included two related secreted and transmembrane (Sectm) 1 genes, Sectm1a and Sectm1b. Refinement of sorting strategies suggested that both Sectm1 products were induced predominantly in conducting airway epithelial cells. Sectm1 was induced during the early stages of pneumococcal pneumonia, and mutation of NF-κB RelA in epithelial cells did not diminish its expression. Instead, type I IFN signaling was necessary and sufficient for Sectm1 induction in lung epithelial cells, mediated by signal transducer and activator of transcription 1. For target cells, Sectm1a bound to myeloid cells preferentially, in particular Ly6G(bright)CD11b(bright) neutrophils in the infected lung. In contrast, Sectm1a did not bind to neutrophils from uninfected lungs. Sectm1a increased expression of the neutrophil-attracting chemokine CXCL2 by neutrophils from the infected lung. We propose that Sectm1a is an epithelial product that sustains a positive feedback loop amplifying neutrophilic inflammation during pneumococcal pneumonia.