Contrasting effects of activating mutations of GαS and the thyrotropin receptor on proliferation and differentiation of thyroid follicular cells

Ludgate, Marian; Gire, Véronique; Crisp, M.; Ajjan, Ramzi; Weetman, Anthony P.; Ivan, Mircea; Wynford-Thomas, David

doi:10.1038/sj.onc.1202864

Cited by 27 publications

(21 citation statements)

References 37 publications

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“…COS-7 cells were propagated in 10% FCS/DMEM; A431 cells and hORI3 were propagated in 10% FCS/RPMI 1640 as described (17,20).…”

Section: Cells Used and Culture Conditionsmentioning

confidence: 99%

“…Recently, we have successfully exploited for the first time a human thyrocyte model using retroviral vectors to compare the biological activity of a single TSHR mutant (A623I) with a G␣s mutant (Q227L) (17). We now report the functional assessment of seven gain-of-function TSHR mutations, spread throughout the TM region, comprising somatic and germline events and having variable activation of Gs/adenylyl cyclase and/or Gq/phospholipase C when measured in COS-7 cells.…”

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confidence: 99%

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Biological Activity of Activating Thyroid-Stimulating Hormone Receptor Mutants Depends on the Cellular Context

et al. 2003

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Activating TSH receptor (TSHR) mutations are a major cause of toxic thyroid adenoma and familial hyperthyroidism, and more than 37 such mutations have been described. Previously their functional activity had been assessed in terms of cAMP and inositol phosphate production and predominantly in transiently transfected COS-7 (monkey embryonic kidney cells), a model that does not reflect effects on thyrocyte proliferation and function. Here we have performed a systematic comparison of wild-type and seven gain-of-function TSHR mutants, introduced into rat FRTL-5 and human thyrocytes, using retroviral vectors. Our results show that 1) biological potency of TSHR mutants in thyroid cells does not correlate with their cAMP levels in transfected COS cells, highlighting the importance of cellular context and level of expression when assessing biological effects of oncogenic mutations; 2) dissociation between stimulation of function and growth occurs with thyrocyte differentiated functions more readily stimulated than growth; 3) TSHR mutants show a similar order of potency in FRTL-5 cells and human thyrocytes; 4) mutants inducing the highest stimulation of adenylyl cyclase may paradoxically fail to induce proliferation; and 5) biological effects of cAMP activating TSHR mutants are attenuated by complex counterregulatory mechanisms at least at the level of phosphodiesterases and cAMP regulatory element modulator isoforms.

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“…COS-7 cells were propagated in 10% FCS/DMEM; A431 cells and hORI3 were propagated in 10% FCS/RPMI 1640 as described (17,20).…”

Section: Cells Used and Culture Conditionsmentioning

confidence: 99%

mentioning

confidence: 99%

Biological Activity of Activating Thyroid-Stimulating Hormone Receptor Mutants Depends on the Cellular Context

et al. 2003

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“…As in benign autonomously functioning thyroid nodules, mutations in either the TSH receptor (TSHR) gene, or the adenylate cyclasestimulating G alpha protein (GNAS1) gene that activates the cAMP cascade, have been detected in a small number of thyroid carcinomas (Russo et al 1995, Spambalg et al 1996, Collins et al 2003, with a handful of those being autonomously hyperfunctioning thyroid carcinomas (Russo et al 1997, Camacho et al 2000, Mircescu et al 2000, Collins et al 2003, Fuhrer et al 2003, Gozu et al 2004, Niepomniszcze et al 2006. Chronic cAMP stimulation may contribute, under certain conditions, to tumor progression (Ludgate et al 1999), although it does not seem sufficient for malignant transformation of thyroid follicular cells, and other genetic alterations are probably required to achieve cancer development (Matsuo et al 1993, Russo et al 1995, Spambalg et al 1996, Ludgate et al 1999, Collins et al 2003, Sobrinho-Simões et al 2008.…”

Section: Introductionmentioning

confidence: 99%

Identification of a paired box gene 8–peroxisome proliferator-activated receptor gamma (PAX8–PPARγ) rearrangement mosaicism in a patient with an autonomous functioning follicular thyroid carcinoma bearing an activating mutation in the TSH receptor

Lado-Abeal¹,

Celestino²,

Bravo³

et al. 2010

Endocrine-Related Cancer

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Our main objective was to search for mutations in candidate genes and for paired box gene 8-peroxisome proliferator-activated receptor gamma (PAX8-PPARg) rearrangement in a well-differentiated angioinvasive follicular thyroid carcinoma (FTC) causing hyperthyroidism. DNA and RNA were extracted from the patient's thyroid tumor, as well as 'normal' thyroid tissue, and from peripheral blood lymphocytes (PBLs) of the patient, her daughter, and two siblings. Nuclear isolation was extracted from the patient's tumor, 'normal' thyroid tissue, PBLs, and uterine leiomyoma tissue. TSH receptor (TSHR ), RAS, and BRAF genes were sequenced. We searched for PAX8-PPARg in thyroid, PBL, and uterine leiomyoma samples from the patient and family members. Proliferative effects of detected mutants on non-transformed human thyrocytes cultures. An activating TSHR mutation, M453T, was detected in the tumor. PAX8 (exons 1-8C10 )-PPARg was found in all tested patient's tissues. A second rearrangement, PAX8 (exons 1-8 )-PPARg, was detected in the patient's normal thyroid tissue. Under deprived medium condition, co-transfection of PAX8-PPARg and TSHR-M453T dramatically increased the number of thyrocytes, an effect that it was not observed with TSHR wild-type (WT); under complete medium conditions, co-transfection of PAX8-PPARg with either TSHR-M453T or TSHR-WT inhibited cell proliferation. We report a patient with hyperthyroidism due to a FTC bearing an activating TSHR mutation and PAX8-PPARg rearrangements. PAX8-PPARg was present as a mosaicism affecting tissues from endodermal and mesodermal origin. PAX8-PPARg and TSHR-M453T inhibited or promoted thyrocyte proliferation depending on medium conditions. The activating TSHR mutation could promote in vivo FTC development in PAX8-PPARg-positive thyrocytes under poor blood supply with deprivation of growth factors but restraint the tumor growth when growth factors are supplied.

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“…However, in contrast to FSHR and LHR, which are expressed in gonads and involved in the animal reproductive cycle (3), TSHR is expressed mainly in thyroid follicular cells and is involved in regulating the body metabolic rate (4,5). Upon TSH (also named thyrotropin) binding, activated TSHR facilitates the synthesis as well as the release of thyroid hormones through the cAMP cascade; this increases the expression of thyroglobulin, thyroid peroxidase, and the sodium/iodine symporter (5,6). Interestingly, in addition to TSH, the newly discovered glycoprotein hormone thyrostimulin, which is composed of glycoprotein ␣2 (GPA2) and glycoprotein ␤5 (GPB5) subunits, has been demonstrated to be a more potent ligand of TSHR than TSH itself (7).…”

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confidence: 99%

Thyrostimulin, but Not Thyroid-stimulating Hormone (TSH), Acts as a Paracrine Regulator to Activate the TSH Receptor in Mammalian Ovary

Sun¹,

Hsu²,

Wu³

et al. 2010

Journal of Biological Chemistry

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The thyroid-stimulating hormone receptor (TSHR), activated by either TSH or the newly discovered glycoprotein hormone thyrostimulin, plays a central role in the control of body metabolism. Interestingly, in addition to its thyroid expression, we discovered that the mRNA level of TSHR is periodically regulated in rat ovary by gonadotropins. Ovarian microdissection followed by real-time PCR analysis indicated that granulosa cells show the highest level of TSHR expression. Cultures of follicles and primary granulosa cells demonstrated that the level of TSHR is up-regulated and decreased by the gonadotropindriven cAMP cascade and estradiol production, respectively. Furthermore, in contrast to the negligible expression of TSH in the ovary, we also found by real-time PCR and immunohistochemical analysis that thyrostimulin is expressed mainly in oocytes. Evolving before the appearance of gonadotropins, thyrostimulin is considered the most ancestral glycoprotein hormone. Therefore, the presence of thyrostimulin in the ovary suggests that it may have a primitive function in reproduction when it activates ovarian TSHR. Next, we generated recombinant thyrostimulin protein and characterized its non-covalent heterodimeric nature. Using purified recombinant thyrostimulin, we show that the human ovarian cell line NIH:OVCAR-3 also expresses endogenous and functional TSHR. Using cultured rat granulosa cells isolated from different ovarian stages, we found that treatments with thyrostimulin significantly increase cAMP production and the c-fos gene response in the presence of gonadotropins. Thus, this study demonstrates that oocyte-derived thyrostimulin and granulosa cell-expressed TSHR compose a novel paracrine system in the ovary, where the activity is tightly controlled by gonadotropins.

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Contrasting effects of activating mutations of GαS and the thyrotropin receptor on proliferation and differentiation of thyroid follicular cells

Cited by 27 publications

References 37 publications

Biological Activity of Activating Thyroid-Stimulating Hormone Receptor Mutants Depends on the Cellular Context

Biological Activity of Activating Thyroid-Stimulating Hormone Receptor Mutants Depends on the Cellular Context

Identification of a paired box gene 8–peroxisome proliferator-activated receptor gamma (PAX8–PPARγ) rearrangement mosaicism in a patient with an autonomous functioning follicular thyroid carcinoma bearing an activating mutation in the TSH receptor

Thyrostimulin, but Not Thyroid-stimulating Hormone (TSH), Acts as a Paracrine Regulator to Activate the TSH Receptor in Mammalian Ovary

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