Neuregulin expression, function, and signaling in human ovarian cancer cells.
OBJECTIVE
To investigate the expression and function of neuregulin (NRG) isoforms in ovarian cancer cell lines and tumor samples.


METHODS
Expression of NRG-1alpha and NRG-1beta proteins were detected by immunohistochemistry and mRNA by RT-PCR. erbB receptor levels and downstream signaling proteins were measured by Western blot analysis.


RESULTS
Expression of NRG-1alpha and NRG-1beta proteins were detected by immunohistochemistry in 46 of 53 (87%) and 41 of 53 (77%) ovarian carcinomas, respectively. Serous carcinomas express higher levels of NRG-1alpha than endometrioid carcinomas (P = 0.017). NRG mRNA was detected by RT-PCR in 20 of 24 (83%) of ovarian carcinomas and eight of nine (89%) ovarian cancer cell lines. NRG-1alpha stimulated the growth of 5 of 14 cell lines whereas NRG-1beta stimulated 7 of 14 cell lines. The magnitude of NRG growth response was significantly associated with erbB2 expression levels. NRG-1alpha and -1beta (1 nM) growth-stimulated cell lines PE01 and PE06 demonstrated increased tyrosine phosphorylation of erbB2 and elevated tyrosine phosphorylation of ERK1 and ERK2. In contrast, the SKOV-3 cell line, the growth of which was unaffected, did not show these downstream responses. An anti-erbB3 receptor antibody (clone H3.105.5) blocked NRG-1beta growth changes and signaling in these cell lines. Conversely, the anti-erbB4 antibody (clone H4.72.8) enhanced NRG-beta1 growth stimulation. Herceptin also inhibited growth.


CONCLUSIONS
With NRG expression in the majority of ovarian carcinomas and cell lines, there is the potential for autocrine regulation of cell growth. Interfering with ligand-receptor interactions by receptor blocking antibodies suggests erbB3 is primarily involved in NRG-1beta-induced proliferation, with erbB4 having a more complex role.
Gilmour
Lynn M R
LM
Cancer Research UK Edinburgh Oncology Unit, Western General Hospital, Edinburgh EH4 2XU, United Kingdom.
Macleod
Kenneth G
KG
McCaig
Alison
A
Sewell
Jane M
JM
Gullick
William J
WJ
Smyth
John F
JF
Langdon
Simon P
SP
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D018262:Adenocarcinoma, Clear Cell / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D018269:Carcinoma, Endometrioid / Q000378:metabolism / Q000473:pathology; D018284:Cystadenocarcinoma, Serous / Q000378:metabolism / Q000473:pathology; D017931:DNA Primers / Q000737:chemistry; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D020890:Neuregulin-1 / Q000235:genetics / Q000378:metabolism*; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D066247:Receptor, ErbB-4; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D020890:Neuregulin-1; D020033:Protein Isoforms; D012333:RNA, Messenger; C587689:ERBB4 protein, human; D066246:ErbB Receptors; D066247:Receptor, ErbB-4