Protein pathway activation mapping reveals molecular networks associated with antiestrogen resistance in breast cancer cell lines.
Previously, we have identified a panel of breast cancer antiestrogen resistance (BCAR) genes. Several of these genes have clinical relevance because mRNA or protein levels associate with tamoxifen resistance or tumor aggressiveness. We postulated that changes in activation status of protein signaling networks induced by BCAR genes may provide better insight into the mechanisms underlying antiestrogen resistance. Key signal transduction pathways were analyzed for changes in activation or expression using reverse-phase protein microarrays probed with 78 antibodies against signaling proteins with known roles in tumorigenesis. We used ZR-75-1-derived cell lines transduced with AKT1, AKT2, BCAR1, BCAR3, BCAR4, EGFR, GRB7, HRAS, HRAS(v12)  or HEF1 and MCF7-derived cell lines transduced with BCAR3, BCAR4 or EGFR. In the antiestrogen-resistant cell lines, we observed increased phosphorylation of several pathways involved in cell proliferation and survival. All tamoxifen-resistant cell lines contained high levels of phosphorylated AKT and its biochemically linked substrates Forkhead box O1/3. The activation of ERBB2, ERBB3 and the downstream modulators focal adhesion kinase and SHC were activated in cells with overexpression of BCAR4. Remarkable differences were observed for the levels of activated AMPK alpha1, cyclins, STAT5, STAT6, ERK1/2 and BCL2. The comparison of the cell signaling networks in estrogen-dependent and -independent cell lines revealed biochemically linked kinase-substrate markers that comprised systemically activated signaling pathways involved in tamoxifen resistance. Our results show that this model provides insights into the molecular and cellular mechanisms of breast cancer progression and antiestrogen resistance. This knowledge may help the development of novel targeted treatments.
Department of Pathology, Josephine Nefkens Institute, Erasmus MC-University Medical Center Rotterdam, The Netherlands. a.vanagthoven@erasmusmc.nl
Ton
T
van Agthoven
Marcia F E
MF
Godinho
Julia D
JD
Wulfkuhle
Emanuel F
EF
Petricoin
Lambert C J
LC
Dorssers
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D050719:Crk-Associated Substrate Protein / Q000235:genetics; D019008:Drug Resistance, Neoplasm; D020847:Estrogen Receptor Modulators / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000096:biosynthesis; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D010766:Phosphorylation; D025941:Protein Interaction Mapping; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins / Q000096:biosynthesis; D015398:Signal Transduction; D013629:Tamoxifen / Q000494:pharmacology*
D048868:Adaptor Proteins, Signal Transducing; D050719:Crk-Associated Substrate Protein; D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt; D018719:Erb-b2 Receptor Tyrosine Kinases; D055765:Shc Signaling Adaptor Proteins; D013629:Tamoxifen; C493841:BCAR1 protein, human; C508053:ERBB2 protein, human