The sub-G1 cell population is indicated by dotted line boxes. of NF-B in and cells, respectively reversed these effects. Thus, loss enhances NF-B activation in lung epithelial cells leading to increased autocrine and paracrine interactions, cell autonomy and enhanced inflammation, which may synergize in the creation of a tumor promoting microenvironment. (18, 19), which is expressed preferentially in lung tissue, predisposes mice to develop spontaneous lung tumors indicating that it functions as a lung-specific tumor suppressor (20). The carcinogenesis process in the knockout (knockout mice are not understood. Here, we report that the loss of in mouse lung epithelial cells results in activation of NF-B and expression of various cytokines and chemokines in vitro and in vivo. These factors increase the proliferation and survival of the epithelial cells as well as induce infiltration of macrophages into the mouse lungs leading to the development of acidophilic macrophage pneumonia (AMP) (21) and the ensuing inflammation. We propose that the increased epithelial cell proliferation and resistance to cell death and the development of an inflammatory microenvironment in the lungs of knockout mice act in concert to promote tumorigenesis. Materials and Methods Animals We used (129sv C57BL/6) F1 wildtype and knockout mice, which recently have been named strain O111:B4; Sigma Chemical Co., St. Louis, MO) or 0.2 mL PBS (control) and killed 4 hr later. Their lungs were excised and processed for: a) analysis of TNF levels by Quantikine Immunoassay (R&D Systems, Minneapolis, MN), b) western blot analysis of Buclizine HCl Ym1 protein, c) preparation of nuclear extract for NF-B DNA-binding analysis by EMSA, and d) fixation in formalin for immunohistochemical analysis of tissue sections for localization of the NF-B subunit p65 as Buclizine HCl described below. Immunoblotting The procedure was performed as described previously (24). Primary polyclonal rabbit antibodies against the following antigens were purchased from the following sources: Ym1 from StemCell Technologies (Vancouver, BC, Canada); I-B (C-21) and p65 (A), from Santa Cruz Biotechnology (Santa Cruz, CA); actin from Sigma-Aldrich (St. Louis, MO). Rabbit antibodies against the Buclizine HCl mouse Gprc5a C-terminal peptide were described (20). Mouse monoclonal antibodies against a Myc epitope peptide tag were from Upstate Biothechnology (Lake Placid, NY). Detection of NF-B MLL3 by immunohistochemistry Histological sections of formalin-fixed and paraffin-embedded lung tissue were incubated with Target Retrieval Solution (pH 6.0, DAKO) then subjected to sequential incubations with rabbit polyclonal antibody against NF-B p65 (14-6731; eBioscience, San Diego, CA), peroxidase conjugated anti-rabbit antibody (EnVision+ Systems, DAKO) and 3,3-diaminobenzidine. Electrophoretic mobility shift assay (EMSA) NF-B DNA-binding activity in nuclear extracts prepared from lung tissues or cell lines (see below) was examined as described (24). The following oligonucleotides were used for the analysis: wildtype NF-B binding oligonucleotide; 5-CGGAAAGTCCCCAGCGGAAAGTCC CTGAT-3; mutant NF-B binding oligonucleotide; 5-CGGAAAGTgagCAGCGGAAAGTGag TGAT-3. Isolation, characterization, and maintenance of mouse tracheal epithelial cells and mouse lung adenocarcinoma cells Epithelial cells were isolated in our laboratory from tracheas dissected from 3-weeks old and male mouse using methods described before (20). Cell proliferation assay Cells were seeded in replicate wells of 96-well plates and grown for 1 to 5 days. The final cell number was estimated using the colorimetric Thiazolyl Blue Tetrazolium Bromide (MTT) viability assay. mRNA analysis and real-time PCR RNA extracted from lung epithelial cells using Tri-Reagent (Molecular Research Center, Cincinnati, OH) was reverse transcribed into cDNA by RETROscript first-strand synthesis Kit (Ambion, Austin, Buclizine HCl TX). The cDNAs were subjected to quantitative PCR (QPCR) using primers for QPCR and TaqMan Gene Expression Master Mix from A&B Applied Biosystems (Austin, Buclizine HCl TX). Mouse actin was used as an internal control gene. The expression data was analyzed and normalized to actin using the 7500 Fast System Software from Applied.
