Cell lines:
- A hammerhead ribozyme strategy was used to achieve down-regulation of ErbB-4 in various breast cancer cell (BCC) lines. Down-regulation of ErbB-4 in
estrogen receptor-positive (ER+) human BCC lines (MCF-7 and T-47D), which express relatively high levels of ErbB-4, significantly inhibited colony formation. No effects were observed in
ER- MDA-MB-453 BCC, which express low levels of endogenous ErbB-4 and high levels of
ErbB-2 and ErbB-3. Furthermore, down-regulation of ErbB-4 in T-47D and MCF-7 cells significantly inhibited tumor formation in athymic nude mice (P < 0.03 and P < 0.001, respectively). In addition, NRG-stimulated phosphorylation of ErbB-4- and NRG-induced colony formation was significantly reduced in ribozyme-transfected T-47D cells (Tang C.K. et al., 1999).
Tumors:
- The expression of ErbB-4 was investigated in human primary breast carcinoma specimens, using immunohistochemical staining with an anti-ErbB-4 monoclonal antibody. ErbB-4 expression was found in 60% of the 50 primary breast tumors examined, and high intense immunoreactivity of ErbB-4 was detected in 18% of these primary breast tumors. ErbB-4 receptor expression appeared to correlate with
ER+ primary breast tumors (Tang C.K. et al., 1999).
