title: LKB1 is required for adiponectin-mediated modulation of AMPK-S6K axis and inhibition of migration and invasion of breast cancer cells.
abstract: Adiponectin is widely known as an adipocytokine with therapeutic potential for its markedly protective function in the pathogenesis of obesity-related disorders, metabolic syndrome, systemic insulin resistance, cardiovascular disease and more recently carcinogenesis. In the present study, we show that adiponectin inhibits adhesion, invasion and migration of breast cancer cells. Further analysis of the underlying molecular mechanisms revealed that adiponectin treatment increased AMP-activated protein kinase (AMPK) phosphorylation and activity as evident by increased phosphorylation of downstream target of AMPK, acetyl-coenzyme A carboxylase and inhibition of p70S6 kinase (S6K). Intriguingly, we discovered that adiponectin treatment increases the expression of tumor suppressor gene LKB1 in breast cancer cells. Overexpression of LKB1 in breast cancer cells further increased adiponectin-mediated phosphorylation of AMPK. Using isogenic LKB1 knockdown cell line pair, we found that LKB1 is required for adiponectin-mediated modulation of AMPK-S6K axis and more importantly, inhibition of adhesion, migration and invasion of breast cancer cells. Taken together these data present a novel mechanism involving specific upregulation of tumor suppressor gene LKB1 by which adiponectin inhibits adhesion, invasion and migration of breast cancer cells. Our findings indicate the possibility of using adiponectin analogues to inhibit invasion and migration of breast cancer cells.
authors.affiliation: Department of Hematology and Medical Oncology, Winship Cancer Institute, Atlanta, GA 30322, USA.
authors.forename: L
authors.initials: L
authors.lastname: Taliaferro-Smith
authors.forename: A
authors.initials: A
authors.lastname: Nagalingam
authors.forename: D
authors.initials: D
authors.lastname: Zhong
authors.forename: W
authors.initials: W
authors.lastname: Zhou
authors.forename: N K
authors.initials: NK
authors.lastname: Saxena
authors.forename: D
authors.initials: D
authors.lastname: Sharma
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D052242:Adiponectin / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology*; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D004789:Enzyme Activation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D009361:Neoplasm Invasiveness; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases
chemical_list: D052242:Adiponectin; D011494:Protein Kinases; C546842:MTOR protein, human; D017346:Protein Serine-Threonine Kinases; D038762:Ribosomal Protein S6 Kinases, 70-kDa; C109790:STK11 protein, human; D058570:TOR Serine-Threonine Kinases; D000091162:AMP-Activated Protein Kinase Kinases