Restoration of SMAD4 by gene therapy reverses the invasive phenotype in pancreatic adenocarcinoma cells.
SMAD4 is a critical cofactor in signal transduction pathways activated in response to transforming growth factor-beta (TGF-beta)-related ligands, regulating cell growth and differentiation. The roles played by SMAD4 inactivation in tumours highlighted it as a tumour-suppressor gene. However, restoration of the TGF-beta antiproliferative pathway following SMAD4 gene transfer in null-tumour cell lines is controversial. Herein, we report the inhibitory effects of SMAD4 on pancreatic tumour invasion and angiogenesis. Adenoviral transfer of this gene in a panel of SMAD4 homozygous-deleted human pancreatic tumour cell lines restored SMAD4 protein expression and function. Although it did not affect proliferation significantly in vitro, SMAD4 inhibited in vivo tumour growth in immunodeficient mice. In this xenograft setting, differential suppression of tumour growth in vivo was mediated, at least in part, through downregulation of vascular endothelial growth factor and expression of gelatinases. We documented the reduced invasion and angiogenesis histologically and by intravital microscopy, and gained mechanistic insight at the messenger and protein level. Finally, we found a negative reciprocal regulation between SMAD4 and ETS-1. ETS-1 is considered a marker for tumour invasion. Upon SMAD4 deletion, we detected high expression levels of ETS-1 in pancreatic tumour cells, suggesting the shift of the pancreatic tumour toward an invasive phenotype.
Duda
Dan G
DG
Division of Gastroenterological Surgery, Graduate School of Medicine, Tohoku University, 980-8574 Sendai, Japan.
Sunamura
Makoto
M
Lefter
Liviu P
LP
Furukawa
Toru
T
Yokoyama
Tadaaki
T
Yatsuoka
Toshimasa
T
Abe
Tadayoshi
T
Inoue
Hiroko
H
Motoi
Fuyuhiko
F
Egawa
Shin-ichi
S
Matsuno
Seiki
S
Horii
Akira
A
D000230:Adenocarcinoma / Q000098:blood supply / Q000235:genetics* / Q000473:pathology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D014408:Biomarkers, Tumor; D017690:Cell Transplantation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D018093:Gelatinases / Q000276:immunology / Q000378:metabolism; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D016147:Genes, Tumor Suppressor; D015316:Genetic Therapy / Q000379:methods*; D008024:Ligands; D051379:Mice; D016513:Mice, SCID; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000235:genetics* / Q000473:pathology; D010641:Phenotype; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000276:immunology / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D012333:RNA, Messenger / Q000378:metabolism; D051901:Smad4 Protein; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000276:immunology / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C494041:ETS1 protein, human; C494042:Ets1 protein, mouse; D008024:Ligands; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D012333:RNA, Messenger; D051901:Smad4 Protein; C490810:Smad4 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D018093:Gelatinases