Gene expression of thyroid-specific transcription factors may help diagnose thyroid lesions but are not determinants of tumor progression.

PURPOSE: The role of thyroid-specific transcription factors in thyroid malignancy is still poorly understood, so we investigate thyroid-specific transcription factors gene expression both in benign and in malignant thyroid nodules, aiming to study a possible clinical utility of these molecules. METHODS: We quantified TTF-1, FOXE1 and PAX8 mRNA levels, relating their expression to diagnostic and prognostic features of thyroid tumors. RNA was extracted from 4 normal thyroid tissues, 101 malignant [99 papillary thyroid carcinomas (PTC) and 2 anaplastic thyroid carcinomas] and 99 benign thyroid lesion tissues [49 goiter and 50 follicular adenomas (FA)]. RESULTS: Levels of mRNA of both FOXE1 (P < 0.0001) and PAX8 (P < 0.0001) genes, but not TTF-1 (P = 0.7056), were higher in benign than in malignant thyroid lesions. FOXE1 was able to identify malignant nodules with 75.8 % sensitivity, 76.1 % specificity, 75.8 % positive predictive value, 76.1 % negative predictive value and 75.9 % accuracy. PAX8 was able to identify malignancy with 60.6 % sensitivity, 81.1 % specificity, 76.9 % positive predictive value, 66.4 % negative predictive value and 70.6 % accuracy. Both FOXE1 and PAX8 gene expression patterns were also able to differentiate FA from the follicular variant of PTC-FVPTC. However, the investigated gene expression was neither associated with any clinical feature of tumor aggressiveness nor associated with recurrence or survival. CONCLUSIONS: We suggest that FOXE1 and PAX8 gene expression patterns may help to diagnose thyroid nodules, identifying malignancy and characterizing follicular-patterned thyroid lesions, but are not determinants of thyroid tumor progression.

Probucol mitigates streptozotocin-induced cognitive and biochemical changes in mice.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by synaptic loss and cognitive impairments. Although AD is the most prevalent aging-related neurodegenerative disease, therapeutic strategies remain palliative. Recent studies have shown that probucol presents neuroprotective effects in experimental models of neurodegenerative disease. The present study aimed to investigate the potential protective effects of probucol against streptozotocin (STZ)-induced cognitive impairment and hippocampal biochemical changes (oxidative stress-related parameters, acetylcholinesterase (AChE) activity, cholesterol levels and ß-secretase (BACE) protein levels) in mice. Adult Swiss mice received STZ [150 µg/bilateral, i.c.v.], and treated daily with probucol (≅10 mg/kg/day, in drinking water, for 5 weeks,). Twenty-one days after i.c.v. administrations, STZ-infused animals displayed significant deficits in cognition (evaluated in the displaced and new object recognition tasks), which were paralleled by a significant increase in hippocampal AChE activity. Moreover, STZ-infused mice showed increased levels of BACE and decreased glutathione reductase (GR) activity in the hippocampus compared with the control group. Probucol treatment significantly protected against the behavioral and hippocampal biochemical changes induced by STZ. However, it was unable to prevent STZ-induced increase of hippocampal BACE levels and did not change hippocampal cholesterol levels. It is noteworthy that probucol treatment increased the glutathione peroxidase (GPx) activity per se independent of STZ injection. The present findings are the first to show that i.c.v. STZ infusions are able to increase hippocampal BACE expression. Moreover, the results also show that probucol can counteract STZ-induced cognitive impairments and biochemical parameters independently of potential modulator effects toward BACE levels. The study is the first to report the protective effects of probucol against STZ-induced biochemical hippocampal changes and behavioral impairments, rendering this compound a promising molecule for further pharmacological studies on the search for therapeutic strategies to treat or prevent AD.