T 84 control IgG [n = 6] HT-29 LMM control IgG [n = 9] anti integrin-β1 [n = 7] anti integrin-β4 [n = 10] anti integrin-αv [n = 8] vehicle [n = 12] neuraminidase type V [n = 8] fucoidane (animals) [n = 7] control medium [n = 5] anti galectin-3 [n = 5] anti TF [n = 4] anti TF + anti galectin-3 [n = 5] ANOVA and post hoc (LSD): * p < 0.05 ** p < 0.001 0-10 16.7 ± 9.0 13.5 ± 5.1 11.4 ± 4.7 13.4 ± 7.6 10.6 ± 5.1 12.8 ± 4.7 7.4 ± 3.0 11.6 ± 6.9 10.9 ± 5.1 18.8 ± 6.7 11.5 ± 14.7 11.6 ± 1.0 11-20 15.8 ± 5.1 13.5 ± 4.8 11.8 ± 4.4 10.7 ± 4.0 10.1 ± 4.1 13.2 ± 6.7 6.6 ± 2.3* 7.4 ± 3.1* 18.3 ± 10.1 13.3 ± 2.4 7.9 ± 4.7* 7.4 ± 2.8** Gassmann et al. BMC Cancer 2010, 10:177 http://www.biomedcentral.com/1471-2407/10/177 Table 1: Pulmonary tumor cell adhesion in vivo Treatment Time intervall after cell injection [min] adherent cells/20 microscopic fileds [mean ± SD] expression was found, α4-integrins were not detected, on the surface of this cell line of epithelial origin (Figure 3A). In accordance with other authors [9] we found sialyl Lewis-a (sLe-a), on HT-29LMM cells, while sialyl Lewis-x (sLe-X) was absent from the cells' surface (Figure 3B). Furthermore, HT-29LMM cells were found to express Galectin-3 and Thomson-Friedenreich antigen (TF) simultaneously (Figure 3B). Integrins are not involved in initial colon cancer cell adhesion within the pulmonary microvasculature We reported earlier that inhibition α6β1- and α6β4-integ- rins as well as inhibition of αvβ5-integrins significantly interfered with metastatic tumor cell adhesion within the hepatic sinusoids [6,17]. Since adhesive interactions of HT-29LMM cells with the pulmonary microvasculature showed comparable patterns, we used the same antibod- ies and protocols for integrin inhibition as described before [6,17] to determine the involvement of integrins in the metastatic cell arrest within the lung. After injection of HT-29LMM cells treated with unspe- cific mouse IgG (n = 9) 13.5 ± 5.1; 13.5 ± 4.8; 11.1 ± 2.7; and 13.5 ± 2.3 cells/20 microscopic fields were found adherent in the lung at 10; 20; 30; and 40 minutes after cell injection, respectively. These numbers were compa- rable to those from untreated cells. Neutralisation of vari- ous integrin subunits at the tumor cells' surfaces did not impair cell adhesion within the lung capillaries (Figure 4B; Table 1). Sialyl Lewis antigens can mediate adhesive tumor cell - microvascular endothelial cell interactions After the identification of selectin binding sLe-a at the cells' surface and with respect to earlier reports indicating sLe-a mediated tumor cell adhesion within the liver [17], HT-29 LMM were pre-treated with neuraminidase type V for enzymatic hydrolization of sialylated residues as described before [17]. This treatment significantly impaired metastatic tumor cell adhesion in the lung as it did in the liver [17]. Using vehicle treated control cells 10.9 ± 3.9 to 15.0 ± 5.9 adherent cells/20 microscopic 21-30 14.1 ± 5.6 11.1 ± 2.7 12.9 ± 2.7 10.4 ± 3.2 9.5 ± 2.5 10.9 ± 3.9 6.5 ± 2.6* 7.2 ± 3.3* 16.4 ± 3.9 13.1 ± 2.9 8.6 ± 3.7** 7.3 ± 2.3** Page 5 of 11 31-40 13.0 ± 1.9 13.5 ± 2.3 12.3 ± 3.8 11.0 ± 4.5 11.7 ± 2.7 15.0 ± 5.9 7.9 ± 2.9** 5.6 ± 2.5** 14.8 ± 6.1 12.3 ± 3.2 7.2 ± 4.0* 6.5 ± 1.4**