, Woburn, MA). Hepatic metastases were produced and quantified as described.19 In some experiments, C26 cells were pretreated in vitro with celecoxib as described above. ManR, ICAM-1, and alpha–smooth muscle actin (ASMA) expression were detected in frozen tissue sections using anti-CD206 monoclonal antibodies (Acris Antibodies, Hiddenhausen, Germany) detected with Alexa488- or Alexa595-conjugated secondary antibodies click here (Invitrogen, Carlsbad, CA), Cy3-conjugated anti-ASMA (Sigma Chemichal, St. Louis, MO), or Alexa488-conjugated ICAM-1 (Novus Biochemicals Inc., Littleton, CO). ManR expression
level was determined as the percentage of hepatic tissue area above a previously determined ManR expression-specific threshold. LSLs were obtained by way of liver
perfusion with phosphate-buffered saline, 0.1 mM ethylene diamine tetraacetic acid, and Ficoll-Hypaque (Amersham, Uppsala, Sweden) gradient centrifugation as described.20 Nonadherent cells were collected and checked for macrophage contamination using anti-murine F4/80 antibodies (AbD Serotec, Kidlington, UK). LSLs were first incubated with primary LSECs for 24 hours in the presence of conditioned medium from untreated C26 cells or pretreated with 20 μM celecoxib, 200 ng/mL soluble ICAM-1 (sICAM-1), or sICAM-1 plus celecoxib. LSECs were first incubated with either untreated or 200 ng/mL sICAM-1 Y-27632 supplier pretreated MCA38/cell-conditioned medium (CM) in those experiments in which ManR−/− mice were used. ManR on LSECs was blocked with the use of 10 μg/mL of specific anti-murine ManR antibodies (Acris Antibodies) added 45
minutes prior to LSLs. Rat immunoglobulin G2a (IgG2a) was used as negative isotype control. The ex vivo cytotoxic activity of LSLs against cancer cells was assayed according to the MTT assay.21 All LSLs were collected and added to C26 target cells at a 5:1 effector/target ratio. After 18-hour coincubation, LSLs were removed from the cultures and MTT was added for 2 hours. LSL cytotoxicity against C26 targets was measured with a Titertek plate scanning colorimeter at 540 nm, and data were expressed as 100 − (optical density in experimental conditions × 100/540 nm optical density in basal conditions). Mice received one single intraperitoneal see more injection of 500 μg/kg anti-murine ManR antibody (rat anti-mouse CD206, isotype IgG2a; Acris Antibodies) 30 minutes prior to cancer cell injection and then the same daily dose on the 24th and 48th hour after cancer cell injection (the last one 45 minutes prior to LSL isolation or ManR endocytosis measurement). Untreated mice underwent the same treatment schedule using rat IgG2a as a control antibody. Data are expressed as the mean ±standard deviation (SD) of three independent experiments. Statistical analysis was performed using SPSS version 13.0 (Professional Statistic, Chicago, IL). Individual comparisons were made using a two-tailed, unpaired Student t test.