Abstract
It is now generally accepted that TGF-β acts as a pro-metastatic factor in advanced human breast cancer. However, it is well documented, that TGF-β is context dependent, and whether the TGF-β pathway switches to promote metastasis during the progression of squamous cell carcinoma (SCC) is unknown. This study examined the role of TGF-β signalling in SCC using a series of genetically related keratinocyte cell lines representing later stages of the disease, stably transduced with a dominant negative TβRII cDNA (dnTβRII). We demonstrated that clones expressing dnTβRII lost their growth inhibitory response to TGF-βin vitro, while ligand expression remained unchanged. Following transplantation of transduced cells to athymic mice in vivo, we showed that attenuation of the TGF-β signal resulted in a loss of differentiation and increased metastasis. In human tissue samples loss of TGF-β signal transduction as measured by pSmad2 activity also correlated with a loss of differentiation. Id1, previously shown to be down regulated by TGF-β, an inhibitor of differentiation and associated with metastasis, was weakly expressed in focal areas of a small number of human tumours but expression did not correlate with low levels of pSmad2. Our data demonstrate that TGF-β does not switch to promote metastasis in late stage human SCC of the skin and that inhibition of TGF-β signalling results in a loss of differentiation and increased metastasis in the later stages of this disease.
Translated title of the contribution | TGF-ß inhibits metastasis in late stage human squamous cell carcinoma of the skin by a mechanism that does not involve Id1 |
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Original language | English |
Pages (from-to) | 107 - 118 |
Number of pages | 11 |
Journal | Cancer Letters |
Volume | 298 |
DOIs | |
Publication status | Published - Jan 2010 |