Sensitivity of breast cancer cell lines to the novel insulin-like growth factor-1 receptor (IGF-1R) inhibitor NVP-AEW541 is dependent on the level of IRS-1 expression.
To investigate the potential value of targeting insulin-like growth factor-1 receptor (IGF-1R) in breast cancer, we examined the effects of NVP-AEW541, a selective small-molecule inhibitor of the IGF-1R tyrosine kinase, in a panel of 16 breast cancer cell lines. All cell lines expressed IGF-1R, but MCF-7 expressed much higher levels of insulin receptor substrate-1 (IRS-1) than the others. NVP-AEW541 was more potent at inhibiting growth of MCF-7 cells as compared to the others (IC(50), 1 microM vs. approximately 7 microM). Comparing MCF-7 to T47D cells, which express IGF-1R at a level identical to MCF-7 but have less than 1/30 the amount of IRS-1, NVP-AEW541 caused cell-cycle arrest at the G1-S boundary, reduced in vitro cell migration, and enhanced the cytotoxic effects of vinorelbine and paclitaxel in MCF-7, but not in T47D. While NVP-AEW541 decreased the phosphorylation of IGF-1R in both cell lines, it inhibited phosphorylation of Akt and disrupted the IRS-1/PI3K complex only in MCF-7. These findings suggest that inhibiting IGF-1R may be an effective therapeutic strategy for breast cancers that co-express IGF-1R and IRS-1 at high levels.
Division of Oncology and Hematology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan. mukohara@med.kobe-u.ac.jp
Toru
T
Mukohara
Hiroyuki
H
Shimada
Naomi
N
Ogasawara
Ryoko
R
Wanikawa
Manami
M
Shimomura
Tetsuya
T
Nakatsura
Genichiro
G
Ishii
Joon Oh
JO
Park
Pasi A
PA
Jänne
Nagahiro
N
Saijo
Hironobu
H
Minami
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D006801:Humans; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000627:therapeutic use*; D011758:Pyrroles / Q000627:therapeutic use*; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism
D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; C501177:NVP-AEW541; D011743:Pyrimidines; D011758:Pyrroles; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D017526:Receptor, IGF Type 1