PTEN deficiency accelerates tumour progression in a mouse model of thyroid cancer.

Abstract

Inactivation and silencing of PTEN have been observed in multiple cancers, including follicular thyroid carcinoma. PTEN (phosphatase and tensin homologue deleted from chromosome 10) functions as a tumour suppressor by opposing the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway. Despite correlative data, how deregulated PTEN signalling leads to thyroid carcinogenesis is not known. Mice harbouring a dominant-negative mutant thyroid hormone receptor beta (TRbeta(PV/PV) mice) spontaneously develop follicular thyroid carcinoma and distant metastases similar to human cancer. To elucidate the role of PTEN in thyroid carcinogenesis, we generated TRbeta(PV/PV) mice haploinsufficient for Pten (TRbeta(PV/PV)Pten(+/-) mouse). PTEN deficiency accelerated the progression of thyroid tumour and increased the occurrence of metastasis spread to the lung in TRbeta(PV/PV)Pten(+/-) mice, thereby significantly reducing their survival as compared with TRbeta(PV/PV)Pten(+/+) mice. AKT activation was further increased by two-fold in TRbeta(PV/PV)Pten(+/-) mice thyroids, leading to increased activity of the downstream mammalian target of rapamycin (mTOR)-p70S6K signalling and decreased activity of the forkhead family member FOXO3a. Consistently, cyclin D1 expression was increased. Apoptosis was decreased as indicated by increased expression of nuclear factor-kappaB (NF-kappaB) and decreased caspase-3 activity in the thyroids of TRbeta(PV/PV)Pten(+/-) mice. Our results indicate that PTEN deficiency resulted in increased cell proliferation and survival in the thyroids of TRbeta(PV/PV)Pten(+/-) mice. Altogether, our study provides direct evidence to indicate that in vivo, PTEN is a critical regulator in the follicular thyroid cancer progression and invasiveness.

• Authors: C J Guigon, L Zhao, M C Willingham, S-Y Cheng
• Journal: Oncogene (Oncogene) Vol. 28 Issue 4 Pg. 509-17 (Jan 29 2009) ISSN: 1476-5594 [Electronic] England
• PMID: 18997818 (Publication Type: Journal Article, Research Support, N.I.H., Intramural)

Chemical References

• Carrier Proteins
• Ccnd1 protein, mouse
• Forkhead Box Protein O3
• Forkhead Transcription Factors
• FoxO3 protein, mouse
• NF-kappa B
• Thyroid Hormone Receptors beta
• Cyclin D1
• Phosphotransferases (Alcohol Group Acceptor)
• MTOR protein, human
• mTOR protein, mouse
• Proto-Oncogene Proteins c-akt
• Ribosomal Protein S6 Kinases, 70-kDa
• TOR Serine-Threonine Kinases
• PTEN Phosphohydrolase
• Pten protein, mouse
• Casp3 protein, mouse
• Caspase 3

Topics

• Animals
• Apoptosis (genetics)
• Carrier Proteins (genetics, metabolism)
• Caspase 3 (genetics, metabolism)
• Cell Proliferation
• Cell Survival (genetics)
• Chromosomes, Mammalian (genetics, metabolism)
• Cyclin D1 (genetics, metabolism)
• Disease Models, Animal
• Enzyme Activation (genetics)
• Forkhead Box Protein O3
• Forkhead Transcription Factors (genetics, metabolism)
• Lung Neoplasms (genetics, metabolism, pathology, secondary)
• Mice
• Mice, Mutant Strains
• Mice, Transgenic
• NF-kappa B (genetics, metabolism)
• Neoplasm Invasiveness
• Neoplasm Metastasis
• PTEN Phosphohydrolase (genetics, metabolism)
• Phosphatidylinositol 3-Kinases (genetics, metabolism)
• Phosphotransferases (Alcohol Group Acceptor) (genetics, metabolism)
• Proto-Oncogene Proteins c-akt (genetics, metabolism)
• Ribosomal Protein S6 Kinases, 70-kDa (genetics, metabolism)
• Signal Transduction (genetics)
• TOR Serine-Threonine Kinases
• Thyroid Hormone Receptors beta (genetics, metabolism)
• Thyroid Neoplasms (genetics, metabolism, pathology)