title: Laminin-5γ-2 (LAMC2) is highly expressed in anaplastic thyroid carcinoma and is associated with tumor progression, migration, and invasion by modulating signaling of EGFR.
abstract: BACKGROUND
  Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy having no effective treatment. Laminin subunit-γ-2 (LAMC2) is an epithelial basement membrane protein involved in cell migration and tumor invasion and might represent an ideal target for the development of novel therapeutic approaches for ATC.
  
  
  OBJECTIVE
  The objective of the investigation was to study the role of LAMC2 in ATC tumorigenesis.
  
  
  METHODS
  LAMC2 expression was evaluated by RT-PCR, Western blotting, and immunohistochemistry in tumor specimens, adjacent noncancerous tissues, and cell lines. The short hairpin RNA (shRNA) approach was used to investigate the effect of LAMC2 knockdown on the tumorigenesis of ATC.
  
  
  RESULTS
  LAMC2 was highly expressed in ATC samples and cell lines compared with normal thyroid tissues. Silencing LAMC2 by shRNA in ATC cells moderately inhibited cell growth in liquid culture and dramatically decreased growth in soft agar and in xenografts growing in immunodeficient mice. Silencing LAMC2 caused cell cycle arrest and significantly suppressed the migration, invasion, and wound healing of ATC cells. Rescue experiments by overexpressing LAMC2 in LAMC2 knockdown cells reversed the inhibitory effects as shown by increased cell proliferation and colony formation. Microarray data demonstrated that LAMC2 shRNA significantly altered the expression of genes associated with migration, invasion, proliferation, and survival. Immunoprecipitation studies showed that LAMC2 bound to epidermal growth factor receptor (EGFR) in the ATC cells. Silencing LAMC2 partially blocked epidermal growth factor-mediated activation of EGFR and its downstream pathway. Interestingly, cetuximab (an EGFR blocking antibody) or EGFR small interfering RNA additively enhanced the antiproliferative activity of the LAMC2 knockdown ATC cells compared with the control cells.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report investigating the effect of LAMC2 on cell growth, cell cycle, migration, invasion, and EGFR signaling in ATC cells, suggesting that LAMC2 may be a potential therapeutic target for the treatment of ATC.
authors.affiliation: Cancer Science Institute of Singapore (M.G., D.K., S.J., V.M., W.C., A.S., LW.D., M.X., L.-Z.L., H.Y., H.P.K.), National University of Singapore, and National University Cancer Institute (H.P.K.), National University Hospital, 117599 Singapore; Division of Hematology/Oncology (R.O., S.G., H.P.K.), Cedars-Sinai Medical Center, and Departments of Pathology and Laboratory Medicine (J.W.S., N.B.D.), Medicine (G.D.B), David Geffen School of Medicine, University of California School of Medicine, Los Angeles, California 90059.
authors.forename: Manoj
authors.initials: M
authors.lastname: Garg
authors.forename: Deepika
authors.initials: D
authors.lastname: Kanojia
authors.forename: Ryoko
authors.initials: R
authors.lastname: Okamoto
authors.forename: Saket
authors.initials: S
authors.lastname: Jain
authors.forename: Vikas
authors.initials: V
authors.lastname: Madan
authors.forename: Wenwen
authors.initials: W
authors.lastname: Chien
authors.forename: Abhishek
authors.initials: A
authors.lastname: Sampath
authors.forename: Ling-Wen
authors.initials: LW
authors.lastname: Ding
authors.forename: Meng
authors.initials: M
authors.lastname: Xuan
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Said
authors.forename: Ngan B
authors.initials: NB
authors.lastname: Doan
authors.forename: Li-Zhen
authors.initials: LZ
authors.lastname: Liu
authors.forename: Henry
authors.initials: H
authors.lastname: Yang
authors.forename: Sigal
authors.initials: S
authors.lastname: Gery
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Braunstein
authors.forename: H Phillip
authors.initials: HP
authors.lastname: Koeffler
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics*; D018450:Disease Progression; D066246:ErbB Receptors / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007797:Laminin / Q000235:genetics*; D051379:Mice; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics; D065646:Thyroid Carcinoma, Anaplastic; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000473:pathology*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: C400567:LAMC2 protein, human; D007797:Laminin; D034741:RNA, Small Interfering; D066246:ErbB Receptors