ABSTRACT
FOXO transcription factors are key regulators of DNA damage repair, proliferation and apoptosis in thyrocytes. Thyroid malignancies show impaired FOXO function. In this study, we investigated the transcriptional regulation of FOXO isoforms in thyroid epithelial cells. mRNA expression of FOXO isoforms (FOXO1, 3 and 4) was determined in FRTL-5 cells stimulated with different growth factors and H2O2. Furthermore, the impact of PI3K/AKT signalling on FOXO transcription was investigated in PI3K p110α mutant FRTL-5 cells and regulatory dependence of FOXO transcription on FOXO was studied in FRTL-5 cells with hFOXO3 overexpression. Finally, mRNA expression levels of FOXO isoforms were determined in human epithelial thyroid tumours. Growth factor deprivation induced transcription of FOXO1, 3 and 4, whereas insulin stimulation decreased FOXO1 and FOXO4 transcription in FRTL-5 cells. Inhibition of the PI3K/AKT cascade amplified FOXO1 and FOXO4 expression. In contrast, H2O2 and TSH did not influence FOXO transcription in thyrocytes. Overexpression of PI3K p110α inhibited FOXO3 and induced FOXO4 transcription. In human thyroid tumours, FOXO1 and FOXO3 mRNA levels were significantly downregulated in papillary thyroid carcinoma when compared to normal tissues. In contrast, follicular thyroid carcinomas showed significant upregulation of FOXO4 mRNA.In this paper, we demonstrate an influence of PI3K signalling on FOXO transcription in thyrocytes. Moreover, we show that thyroid cancers exhibit alterations in FOXO transcription besides the previously reported alterations in posttranslational FOXO3 regulation. These findings may add to the concept of targeting the PI3K pathway in advanced thyroid cancers.
Subject(s)
Adenocarcinoma, Follicular/genetics , Adenoma/genetics , Forkhead Transcription Factors/genetics , Gene Expression Regulation, Neoplastic , Thyroid Epithelial Cells/metabolism , Thyroid Neoplasms/genetics , Adenocarcinoma, Follicular/pathology , Adenoma/pathology , Animals , Cell Cycle Proteins , Cells, Cultured , Forkhead Box Protein O1/genetics , Forkhead Box Protein O3/genetics , Humans , Phosphatidylinositol 3-Kinases/genetics , Proto-Oncogene Proteins c-akt/genetics , RNA, Messenger/genetics , Rats , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction , Thyroid Epithelial Cells/pathology , Thyroid Neoplasms/pathology , Transcription Factors/genetics , Transcriptional ActivationABSTRACT
Aberrations in the control of apoptosis represent a central feature of thyroid carcinogenesis. However, little is known about the regulation of components of the intrinsic apoptosis pathway in the thyroid. Using a real-time PCR approach we investigated the mRNA expression levels of Caspase3, Caspase3 s, xIAP, Bad, and beta-actin in a panel of 79 thyroid tumours. Additionally, we assessed the activation status of Caspase3 by immunohistochemistry. In the present study, we provide first evidence for a deregulation of the intrinsic apoptosis pathway on the transcriptional and post-transcriptional level. Thus, malignant thyroid tumours revealed a significant downregulation of the proapoptotic Bad. In contrast Caspase3 s, an alternative splice variant of Caspase3 with anti-apoptotic characteristics, was upregulated in follicular and anaplastic cancers. Moreover, papillary thyroid tumours revealed a significant upregulation of Caspase3 mRNA. On the post-translational level, thyroid malignancies featured an impairment in the activation of Caspase3, since activated Caspase3 accumulated exclusively in the cytoplasm of thyroid cancer cells, whereas follicular adenoma and normal thyroid tissues showed no cytoplasmatic but nuclear Caspase3 distribution. Further knowledge on apoptosis-deregulation during thyroid carcinogenesis might confer diagnostic and therapeutic benefits in the management of thyroid cancer.
Subject(s)
Apoptosis/genetics , Thyroid Neoplasms/genetics , Thyroid Neoplasms/pathology , Caspase 3/genetics , Caspase 3/metabolism , Enzyme Activation , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , RNA, Messenger/genetics , RNA, Messenger/metabolism , Thyroid Neoplasms/enzymology , bcl-Associated Death Protein/genetics , bcl-Associated Death Protein/metabolismSubject(s)
Cell Proliferation/drug effects , Insulin/analogs & derivatives , Insulin/pharmacology , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Thyroid Gland/drug effects , Animals , Blotting, Western , Cell Line, Tumor , Dose-Response Relationship, Drug , Forkhead Box Protein O3 , Forkhead Transcription Factors/genetics , Forkhead Transcription Factors/metabolism , Humans , Insulin Glargine , Insulin, Long-Acting , Phosphatidylinositol 3-Kinases/genetics , Proto-Oncogene Proteins c-akt/genetics , Rats , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/physiology , Thyroid Gland/cytology , Thyroid Gland/metabolismABSTRACT
This study investigated the relationship between music listening preferences and preadmission, dysfunctional psychosocial behaviors (PDPB) of 60 adolescents who were hospitalized on an in-patient psychiatric unit. Findings were that hospitalized adolescents who primarily listened to music with negative lyrics/themes had a history of more PDPB than hospitalized adolescents who primarily listened to music that did not contain negative lyrics/themes; and hospitalized adolescents who primarily listened to heavy metal music had a history of more PDPB than hospitalized adolescents who primarily listened to other types of music.
