Inverse relationship between estrogen receptor and epidermal growth factor receptor mRNA levels in human breast cancer cell lines.
Epidermal growth factor receptors (EGF-R) are present in a number of human breast cancer cell lines and tumor biopsies. Furthermore, it has been suggested that EGF-R levels are higher in estrogen receptor negative (ER-) than in ER+ human breast tumors and that EGF-R status may be a prognostic indicator in breast cancer. The present study was undertaken to establish whether there is a quantitative relationship between EGF-R and ER mRNA concentrations in a series of 10 well-characterized human breast cancer cell lines. All cell lines expressed detectable quantities of EGF-R mRNA by Northern analysis but the relative abundance of EGF-R mRNA varied more than 50-fold. Two transcripts corresponding to the 10.5- and 5.8-kb mRNAs described in other cell types were present but in different relative proportions in different cell lines. When these lines were divided into an ER+ and an ER- group based on their ability to bind estradiol, ER- cell lines were shown to express significantly higher concentrations of EGF-R mRNA than did ER+ cell lines (p less than 0.005). Furthermore, linear-regression analysis revealed a significant inverse relationship between ER and EGF-R mRNA concentrations both within the group of 10 human breast cancer cell lines as a whole (r = 0.66) and within the 6 functionally ER + lines (r = 0.77). This demonstration of a significant (p less than 0.005) inverse relationship between the concentrations of ER and EGF-R mRNAs in ER + cell lines raises the possibility of reciprocal regulation of the expression of these genes in human breast cancer.
Lee
C S
CS
Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, N.S.W., Australia.
Hall
R E
RE
Alexander
I E
IE
Koga
M
M
Shine
J
J
Sutherland
R L
RL
D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000235:genetics* / Q000378:metabolism; D012044:Regression Analysis; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D011960:Receptors, Estrogen; D066246:ErbB Receptors