Correlation of glypican-1 expression with TGF-beta, BMP, and activin receptors in pancreatic ductal adenocarcinoma.
Glypican1 (GPC1) is a cell surface heparan sulfate proteoglycan that acts as a co-receptor for heparin-binding growth factors as well as for members of the TGF-beta family. GPC1 plays a role in pancreatic cancer by regulating growth factor responsiveness. In view of the importance of members of the TGF-beta family in pancreatic cancer, in the present study, the role of GPC1 in TGF-beta, BMP and activin signaling was analyzed. Quantitative RT-PCR and immunohistochemistry were utilized to analyze GPC1 and TGF-beta, BMP and activin receptor expression levels. Panc-1 and T3M4 pancreatic cancer cells were transfected in a stable manner with a GPC1 antisense expression construct. Anchorage-dependent and -independent growth was determined by MTT and soft agar assays. TGF-beta1, activin-A and BMP-2 responsiveness was determined by MTT assays and immunoblotting with p21, p-Smad1, and p-Smad2 antibodies. QRT-PCR demonstrated increased GPC1 mRNA levels in pancreatic ductal adenocarcinoma (PDAC) compared to normal pancreatic tissues (NPT), as described previously. There was a significant correlation between GPC1 mRNA levels and TbetaRII, act-R1a, act-R1b, act-R2a, BMP-R1a, and BMP-R2 mRNA expression in NPT. In contrast, GPC1 mRNA expression correlated directly with act-R1a and BMP-R1a in N0 PDAC cases and with act-R2a and BMP-R1a in lymph node positive cases. Down-regulation of GPC1 resulted in increased doubling time in Panc-1 but not in T3M4 cells, and decreased anchorage-independent growth in both cell lines. GPC1 down-regulation resulted in a slightly altered response towards TGF-beta1, activin-A and BMP-2 in terms of growth, p21 induction and Smad2 phosphorylation. In conclusion, enhanced GPC1 expression correlates with BMP and activin receptors in pancreatic cancer. GPC1 down-regulation suppresses pancreatic cancer cell growth and slightly modifies signaling of members of the TGF-beta family of growth factors.
Kayed
Hany
H
Department of General Surgery, University of Heidelberg, D-69120 Heidelberg, Germany.
Kleeff
Jörg
J
Keleg
Shereen
S
Jiang
Xiaohua
X
Penzel
Roland
R
Giese
Thomas
T
Zentgraf
Hanswalter
H
Büchler
Markus W
MW
Korc
Murray
M
Friess
Helmut
H
D029404:Activin Receptors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D052004:Bone Morphogenetic Protein Receptors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation; D005260:Female; D053673:Glypicans / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
C000621866:GPC1 protein, human; D053673:Glypicans; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D029404:Activin Receptors; D052004:Bone Morphogenetic Protein Receptors