Reduced expression of EphB2 that parallels invasion and metastasis in colorectal tumours

Abstract

EphB2, a receptor tyrosine kinase regulated by the beta-catenin/Tcf4 complex, is expressed in the proliferative compartment of mouse intestine and regulates bidirectional migration of intestinal precursor cells in the crypt-villus axis through repulsive interaction with Ephrin-B ligands. Recently, it has been shown that reduction of EphB activity accelerates colon tumour progression in the Apc(Min/+) mice. In this study, we examined the expression of EphB2 in normal colon, adenomas, primary colorectal cancers (CRCs), lymph node metastases and liver metastases using immunohistochemistry on tissue microarrays. In addition, EphB2 was overexpressed in SW480 colon cancer cells to study its effect in vitro. We found that EphB2 was expressed in 100% of normal colon crypt base cells, 78% of adenomas, 55.4% of primary CRCs, 37.8% of lymph node metastases and 32.9% of liver metastases (all differences were statistically significant at P < 0.001 compared with primary CRCs). Patients with CRCs that lose EphB2 expression had more advanced tumour stage (P = 0.005), poor differentiation (P < 0.001), poor overall survival (P = 0.005) and disease-free survival (P = 0.001), with the latter being independent of tumour stage. In vitro studies showed that overexpression of EphB2 inhibited colon cancer cell growth in colony formation assay and activation of EphB2 receptor inhibited colon cancer cell adhesion and migration. Our data demonstrated a progressive loss of EphB2 expression in each critical step of colon carcinogenesis, including the onset of invasion, dedifferentiation and metastasis which are paralleled by adverse patient outcome. EphB2 may achieve its tumour suppressor function through regulation of cell survival, adhesion and migration.

Analysis of KRAP expression and localization, and genes regulated by KRAP in a human colon cancer cell line

“…MAP4K3 is a component in the nutrient-responsive pathway affecting cell growth (Findlay et al 2007). Deregulated expression of various EPH receptors, including EPHB2, has been reported in diverse tumor types (Guo et al 2006;Jubb et al 2005). All of these results suggested that KRAP might play critical roles in cancer-associated signaling pathways, including Ras, MAPKs (MAP kinases), integrins, EPH receptors, and protein kinase C.…”

Basic transcription factor 3 (BTF3) regulates transcription of tumor-associated genes in pancreatic cancer cells

“…Thereafter, the slides were placed in washing buffer (10 mM Tris-HCl, 0.85% NaCl, 0.1% bovine serum albumin, pH 7.4). After antigens were retrieved by boiling the tissue sections in 10 mM citrate buffer for 20 min in the microwave oven, consecutive sections were incubated with rabbit polyclonal BTF3a/b antibodies (Zymed Laboratories, Inc., Karlsruhe, Germany), goat polyclonal EPHB2 antibodies (R&D systems, Wiesbaden-Nordenstadt, Germany), 18 or normal rabbit or goat IgG (DAKO) as negative controls in an antibody diluent with background-reducing components (DAKO) at 4˚C overnight. For BTF3 and EPHB2 detection, the slides were incubated with HRPO-conjugated anti-rabbit IgG (Amersham International, Buckinghamshire, UK) and anti-goat IgG (Invitrogen GmbH, Karlsruhe, Germany), respectively, for 1 h at room temperature.…”

Identification of alterations in DNA copy number in host stromal cells during tumor progression

“…Although primarily involved in mediating developmental events directed by Ephrin (17), particularly in the nervous system, many studies have indicated a direct role for the ephrins and their receptors in tumor progression and angiogenesis (18). Increased expression of Ephrins and their receptors have been correlated with survival and invasive capacity of colorectal and ovarian cancers (19)(20)(21). Additionally, EphA2 and EphB2 have emerged as attractive drug targets for cancer therapy (22,23).…”