Coexpression of ephrin-Bs and their receptors in colon carcinoma.
BACKGROUND
The erythropoietin-producing hepatoma amplified sequence (Eph) family is the largest subfamily of receptor tyrosine kinases (RTKs). The Ephs (receptors) bind to specific cell-bound ligands, called ephrins. The binding of this ligand-receptor system is dependent on cell-cell interactions. The ephrin-Eph system is important in embryologic development and differentiation of the nervous and vascular systems. In the current study, the authors hypothesized that ephrins may play a role in the growth and development of colon carcinoma and may be expressed differentially in normal and malignant colonic tissues.


METHODS
Reverse transcriptase-polymerase chain reaction (RT-PCR), Northern Blot analyses, and immunohistochemistry were used to examine 11 colon carcinoma cell lines and 20 human colon carcinoma specimens with adjacent uninvolved mucosa for the expression of EphB and ephrin-B family members.


RESULTS
EphB2, EphB3, and EphB4 mRNA expression and ephrin-B2 mRNA expression was detected in all the cell lines and colon carcinoma specimens examined. Immunohistochemical analysis showed that ephrin-B2 had higher expression in the colon carcinoma specimens studied than in adjacent normal mucosa. Ephrin-B2 and EphB4 most frequently were expressed on the luminal surface of colon carcinoma epithelium.


CONCLUSIONS
The results of the current suggest that the ephrin-Bs are expressed differentially in colon carcinoma and normal mucosa specimens and thus may play a role in the progression of colon carcinoma. Further studies are necessary to determine the functional role of ephrin-Bs in colon carcinoma angiogenesis and growth.
Liu
Wenbiao
W
Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Ahmad
Syed A
SA
Jung
Young D
YD
Reinmuth
Niels
N
Fan
Fan
F
Bucana
Corazon D
CD
Ellis
Lee M
LM
D014408:Biomarkers, Tumor / Q000032:analysis*; D015152:Blotting, Northern; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D002471:Cell Transformation, Neoplastic; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D017931:DNA Primers; D018450:Disease Progression; D036388:Ephrin-B2; D036389:Ephrin-B3; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis*; D036224:Receptor, EphB4; D036081:Receptors, Eph Family; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D017931:DNA Primers; D036388:Ephrin-B2; D036389:Ephrin-B3; D008565:Membrane Proteins; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases; D036224:Receptor, EphB4; D036081:Receptors, Eph Family