title: Enhanced expression of LKB1 in breast cancer cells attenuates angiogenesis, invasion, and metastatic potential.
abstract: LKB1 (also known as STK11) is a recently identified tumor suppressor gene whose mutation can lead to Peutz-Jeghers syndrome, which is characterized by gastrointestinal polyps and cancers of different organ systems. Approximately 30% of sporadic breast cancer samples express low levels of LKB1. This suggests that the LKB1 gene may be related to the tumorigenesis of breast cancer. We reintroduced LKB1 into MDA-MB-435 breast cancer cells that lack the LKB1 gene to investigate how overexpression of LKB1 affects tumor invasiveness and metastasis. Overexpression of the LKB1 protein in breast cancer cells resulted in significant inhibition of in vitro invasion. In vivo, LKB1 expression reduced tumor growth in the mammary fat pad, microvessel density, and lung metastasis. LKB1 overexpression was associated with down-regulation of matrix metalloproteinase-2, matrix metalloproteinase-9, vascular endothelial growth factor, and basic fibroblast growth factor mRNA and protein levels. Overexpression of the LKB1 protein in human breast cancer is significantly associated with a decrease in microvessel density. Our results indicate that LKB1 plays a negative regulatory role in human breast cancer, a finding that may lead to a new therapeutic strategy.
authors.affiliation: Breast Cancer Institute, Cancer Hospital, Department of Oncology, Shanghai Medical College, Institutes of Biomedical Science, Fudan University, Shanghai, People's Republic of China.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Zhuang
authors.forename: Gen-Hong
authors.initials: GH
authors.lastname: Di
authors.forename: Zhen-Zhou
authors.initials: ZZ
authors.lastname: Shen
authors.forename: Jian
authors.initials: J
authors.lastname: Ding
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Shao
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D000328:Adult; D000368:Aged; D000818:Animals; D001943:Breast Neoplasms / Q000098:blood supply* / Q000201:enzymology / Q000473:pathology*; D002196:Capillaries / Q000473:pathology; D045744:Cell Line, Tumor; D015536:Down-Regulation; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000556:secondary; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D042461:Vascular Endothelial Growth Factor A; D005346:Fibroblast Growth Factors; D017346:Protein Serine-Threonine Kinases; C109790:STK11 protein, human; D000091162:AMP-Activated Protein Kinase Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9