Restoration of TGF-beta signalling reduces tumorigenicity in human lung cancer cells.
Members of the transforming growth factor-beta (TGF-beta) family regulate a wide range of biological processes including cell proliferation, migration, differentiation, apoptosis, and extracellular matrix deposition. Resistance to TGF-beta-mediated tumour suppressor function in human lung cancer may occur through the loss of type II receptor (TbetaRII) expression. In this study, we investigated the expression pattern of TbetaRII in human lung cancer tissues by RT-PCR and Western blot analyses. We observed downregulation of TbetaRII in 30 out of 46 NSCLC samples (65%) by semiquantitative RT-PCR. Western blot analyses with tumour lysates showed reduced expression of TbetaRII in 77% cases. We also determined the effect of TbetaRII expression in lung adenocarcinoma cell line (VMRC-LCD) that is not responsive to TGF-beta due to lack of TbetaRII expression. Stable expression of TbetaRII in these cells restored TGF-beta-mediated effects including Smad2/3 and Smad4 complex formation, TGF-beta-responsive reporter gene activation, inhibition of cell proliferation and increased apoptosis. Clones expressing TbetaRII showed reduced colony formation in soft-agarose assay and significantly reduced tumorigenicity in athymic nude mice. Therefore, these results suggest that reestablishment of TGF-beta signalling in TbetaRII null cells by stable expression of TbetaRII can reverse malignant behaviour of cells and loss of TbetaRII expression may be involved in lung tumour progression.
Anumanthan
G
G
Department of Surgery and Cancer Biology, Division of Surgical Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Halder
S K
SK
Osada
H
H
Takahashi
T
T
Massion
P P
PP
Carbone
D P
DP
Datta
P K
PK
D000818:Animals; D017209:Apoptosis; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism; D015533:Transcriptional Activation; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D050759:Cyclin-Dependent Kinase Inhibitor p21; D018125:Receptors, Transforming Growth Factor beta; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II