title: Survivin upregulation, dependent on leptin-EGFR-Notch1 axis, is essential for leptin-induced migration of breast carcinoma cells.
abstract: Obese breast cancer patients exhibit a higher risk for larger tumor burden and an increased likelyhood of metastasis. The molecular effects of obesity on carcinogenesis are mediated by the autocrine and paracrine effects of the adipocytokine leptin. Leptin participates in the tumor progression and metastasis of human breast. We show that leptin induces clonogenicity and increases the migration potential of breast cancer cells. We found that survivin expression is induced in response to leptin. In this study, we examine the role and leptin-mediated regulation of survivin. Leptin treatment leads to survivin upregulation, due in part to the activation of Notch1 and the release of a transcriptionally active Notch1 intracellular domain (NICD). Chromatin immunoprecipitation analysis shows that NICD gets recruited to the survivin promoter at the CSL (CBF1/RBP-Jk, Su(H), Lag-1) binding site in response to leptin treatment. Inhibition of Notch1 activity inhibits leptin-induced survivin upregulation. Leptin-induced transactivation of epidermal growth factor receptor (EGFR) is involved in leptin-mediated Notch1 and survivin upregulation, demonstrating a novel upstream role of leptin-EGFR-Notch1 axis. We further show that leptin-induced migration of breast cancer cells requires survivin, as overexpression of survivin further increases, whereas silencing survivin abrogates leptin-induced migration. Using a pharmacological approach to inhibit survivin, we show that 3-hydroxy-3-methylglutaryl-coenzyme-A-reductase inhibitors, such as lovastatin, can effectively inhibit leptin-induced survivin expression and migration. Importantly, leptin increased breast tumor growth in nude mice. These data show a novel role for survivin in leptin-induced migration and put forth pharmacological survivin inhibition as a potential novel therapeutic strategy. This conclusion is supported by in vivo data showing the overexpression of leptin and survivin in epithelial cells of high-grade ductal carcinomas in situ and in high-grade invasive carcinomas.
authors.affiliation: Department of Hematology and Medical Oncology, Emory University School of Medecine, Atlanta, Georgia 30322, USA.
authors.forename: Brandi B
authors.initials: BB
authors.lastname: Knight
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Oprea-Ilies
authors.forename: Arumugam
authors.initials: A
authors.lastname: Nagalingam
authors.forename: Lily
authors.initials: L
authors.lastname: Yang
authors.forename: Cynthia
authors.initials: C
authors.lastname: Cohen
authors.forename: Neeraj K
authors.initials: NK
authors.lastname: Saxena
authors.forename: Dipali
authors.initials: D
authors.lastname: Sharma
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D047369:Chromatin Immunoprecipitation; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D051034:Inhibitor of Apoptosis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020738:Leptin / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D012333:RNA, Messenger / Q000235:genetics; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D000077022:Survivin; D015854:Up-Regulation; D014945:Wound Healing
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D020738:Leptin; C497761:NOTCH1 protein, human; D012333:RNA, Messenger; D051881:Receptor, Notch1; D000077022:Survivin; C512478:EGFR protein, human; D066246:ErbB Receptors