Mutation of Thyroid Hormone Receptor-&Beta
Oncogene (2011) 30, 3381–3390 & 2011 Macmillan Publishers Limited All rights reserved 0950-9232/11 www.nature.com/onc ORIGINAL ARTICLE Mutation of thyroid hormone receptor-b in mice predisposes to the development of mammary tumors CJ Guigon1, DW Kim1, MC Willingham2 and S-y Cheng1 1Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA and 2Department of Pathology, Wake Forest University, Winston-Salem, NC, USA Correlative data suggest that thyroid hormone receptor-b Introduction (TRb) mutations could increase the risk of mammary tumor development, but unequivocal evidence is still Thyroid hormone receptors (TRs) belong to the lacking. To explore the role of TRb mutants in vivo in superfamily of nuclear receptors that are ligand- breast tumor development and progression, we took dependent transcription factors. Two TR genes, THRA advantage of a knock-in mouse model harboring a and THRB, located on chromosomes 17 and 3, respec- mutation in the Thrb gene encoding TRb (ThrbPV mouse). tively, encode four thyroid hormone (T3)-binding Although in adult nulliparous females, a single ThrbPV receptors: TRa1, TRb1, TRb2 and TRb3. They bind allele did not contribute to mammary gland abnormalities, T3 that has critical roles in differentiation, growth and the presence of two ThrbPV alleles led to mammary metabolism (Yen, 2001). hyperplasia in B36% ThrbPV/PV mice. The ThrbPV Several findings support the notion that mutations of mutation further markedly augmented the risk of TRs can be associated with cancer. Early evidence mammary hyperplasia in a mouse model with high suggested that mutated TRs could be involved in susceptibility to mammary tumors (Pten þ /À mouse), as carcinogenesis came from the discovery that v-erbA, a demonstrated by the occurrence of mammary hyperplasia highly mutated chicken THRA1 that has lost the ability in B60% of ThrbPV/ þ Pten þ /À and B77% of ThrbPV/PV to activate gene transcription, leads to neoplastic trans- Pten þ /À mice versus B33% of Thrb þ / þ Pten þ /À mice.
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