Sp1-mediated transactivation of LamC1 promoter and coordinated expression of laminin-gamma 1 and Sp1 in human hepatocellular carcinomas
AMERICAN JOURNAL OF PATHOLOGY
Authors: Lietard, J; Musso, O; Theret, N; LHelgoualch, A; Campion, JP; Yamada, Y; Clement, B
Abstract
The laminin-gamma 1 chain is present in most basement membranes and is involved in various physiological and pathological processes, including carcinogenesis in the liver. We have investigated the role of the transcription factor Sp1 in the activation of the LamC1 gene, which encodes laminin-gamma 1, both in hepatocytes and in human hepatocellular carcinomas. DNAse I hypersensitive sites were mapped in the murine LamC1 promoter using early hepatocyte primary cultures in which LamC1 becomes activated, Three hypersensitive sites were found in enhancer-like elements that contain GC-rich regions. Gel-shift analyses showed that specific complexes were resolved using GC-containing oligonucleotides and Faza 567 hepatoma cells, which constitutively express laminin-gamma 1 at a high level. Increased GC-binding activity was observed using nuclear extracts from early hepatocyte cultures versus normal liver. Sp1 overexpression in normal hepatocytes transfected with an Sp1 expression vector induced a marked increased of laminin-gamma 1 mRNA content and co-transfection of promoter fragments in Drosophila melanogaster SL2 cells demonstrated that Spl transactivates LamC1. In human hepatocellular carcinomas, Sp1 and laminin-gamma 1 mRNA were simultaneously expressed at high levels, and gel-shift experiments demonstrated a higher GC-binding activity to Sp1 compared with control Livers. In situ hybridization indicated that cells exhibiting a high content of laminin-gamma 1 mRNA were also strongly positive for Sp1 mRNA, including both cancer cells at the invasion front and stromal cells. These results show that Sp1 is involved in the activation of LamC1 that occurs in human hepatocellular carcinomas.
Genome-wide association study identifies three novel loci in Fuchs endothelial corneal dystrophy
NATURE COMMUNICATIONS
Authors: Afshari, Natalie A.; Igo, Robert P., Jr.; Morris, Nathan J.; Stambolian, Dwight; Sharma, Shiwani; Pulagam, V. Lakshmi; Dunn, Steven; Stamler, John F.; Truitt, Barbara J.; Rimmler, Jacqueline; Kuot, Abraham; Croasdale, Christopher R.; Qin, Xuejun; Burdon, Kathryn P.; Riazuddin, S. Amer; Mills, Richard; Klebe, Sonja; Minear, Mollie A.; Zhao, Jiagang; Balajonda, Elmer; Rosenwasser, George O.; Baratz, Keith H.; Mootha, V. Vinod; Patel, Sanjay V.; Gregory, Simon G.; Bailey-Wilson, Joan E.; Price, Marianne O.; Price, Francis W., Jr.; Craig, Jamie E.; Fingert, John H.; Gottsch, John D.; Aldave, Anthony J.; Klintworth, Gordon K.; Lass, Jonathan H.; Li, Yi-Ju; Iyengar, Sudha K.
Abstract
The structure of the cornea is vital to its transparency, and dystrophies that disrupt corneal organization are highly heritable. To understand the genetic aetiology of Fuchs endothelial corneal dystrophy (FECD), the most prevalent corneal disorder requiring transplantation, we conducted a genome-wide association study (GWAS) on 1,404 FECD cases and 2,564 controls of European ancestry, followed by replication and meta-analysis, for a total of 2,075 cases and 3,342 controls. We identify three novel loci meeting genome-wide significance (P<5 x 10(-8)): KANK4 rs79742895, LAMC1 rs3768617 and LINC00970/ATP1B1 rs1200114. We also observe an overwhelming effect of the established TCF4 locus. Interestingly, we detect differential sex-specific association at LAMC1, with greater risk in women, and TCF4, with greater risk in men. Combining GWAS results with biological evidence we expand the knowledge of common FECD loci from one to four, and provide a deeper understanding of the underlying pathogenic basis of FECD.