AND-34 activates phosphatidylinositol 3-kinase and induces anti-estrogen resistance in a SH2 and GDP exchange factor-like domain-dependent manner.
AND-34, a 95-kDa protein with modest homology to Ras GDP exchange factors, associates with the focal adhesion protein p130Cas. Overexpression of AND-34 confers anti-estrogen resistance in breast cancer cell lines, a property linked to its ability to activate Rac. Here, we show that both the GDP exchange factor-like domain and the SH2 domain of AND-34 are required for Rac activation and for resistance to the estrogen receptor (ER) antagonist ICI 182,780. As phosphatidylinositol 3-kinase (PI3K) signaling can regulate Rac activation, we examined the effects of AND-34 on PI3K. Overexpression of AND-34 in MCF-7 cells increased PI3K activity and augmented Akt Ser(473) phosphorylation and kinase activity. Inhibition of PI3K with LY294002 or a dominant-negative p85 construct blocked AND-34-mediated Rac and Akt activation. Although R-Ras can activate PI3K, transfection with constitutively active R-Ras failed to induce Rac activation and AND-34 overexpression failed to induce R-Ras activation. Treatment of either vector-only or AND-34-transfected ZR-75-1 cells with ICI 182,780 markedly diminished ERalpha levels, suggesting that AND-34-induced anti-estrogen resistance is likely to occur by an ERalpha-independent mechanism. Treatment of a ZR-75-1 breast cancer cell line stably transfected with AND-34 plus 2 micromol/L LY294002 or 10 micromol/L NSC23766, a Rac-specific inhibitor, abrogated AND-34-induced resistance to ICI 182,780. Our studies suggest that AND-34-mediated PI3K activation induces Rac activation and anti-estrogen resistance in human breast cancer cell lines.
Felekkis
Kyriacos N
KN
Department of Medicine, Section of Hematology and Oncology, Boston Medical Center, Boston, MA 02118, USA.
Narsimhan
Radha P
RP
Near
Richard
R
Castro
Ariel F
AF
Zheng
Yi
Y
Quilliam
Lawrence A
LA
Lerner
Adam
A
D048868:Adaptor Proteins, Signal Transducing; D001943:Breast Neoplasms / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002867:Chromones / Q000494:pharmacology; D050719:Crk-Associated Substrate Protein; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000378:metabolism; D004967:Estrogens / Q000378:metabolism; D022001:Focal Adhesions; D000077267:Fulvestrant; D020558:GTP Phosphohydrolases / Q000378:metabolism; D005799:Genes, Dominant; D005822:Genetic Vectors; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011960:Receptors, Estrogen / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D014162:Transfection; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D002867:Chromones; D050719:Crk-Associated Substrate Protein; D004958:Estradiol; D004965:Estrogen Antagonists; D004967:Estrogens; D000077267:Fulvestrant; D020558:GTP Phosphohydrolases; D020662:Guanine Nucleotide Exchange Factors; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011960:Receptors, Estrogen; D050717:Retinoblastoma-Like Protein p130; D012694:Serine; D020744:rac GTP-Binding Proteins; C493841:BCAR1 protein, human; C120867:Bcar3 protein, mouse; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C494918:AKT1 protein, human