In PCOS patients the addition of low-dose spironolactone induces a more marked reduction of clinical and biochemical hyperandrogenism than metformin alone.

BACKGROUND & AIMS: Polycystic ovary syndrome (PCOS) is characterized by ovarian dysfunction and hyperandrogenism and by insulin resistance and related metabolic alterations. Both metformin and anti-androgens, such as spironolactone, are used to ameliorate the different aspects of this disorder. We investigated whether therapy with metformin plus low-dose spironolactone is more effective than metformin alone in PCOS patients. METHODS AND RESULTS: Fifty-six PCOS patients were randomized in two groups: group A (28 patients) was treated with metformin (1700 mg/die) and group B (28 patients) was treated with metformin (1700 mg/die) plus low-dose spironolactone (25 mg/die). Anthropometric, hormonal and metabolic parameters were evaluated at baseline and after six months of treatment. After therapy regular menses were restored in approximately 82% of group A patients (P < 0.001) and in 68% of group B patients (P < 0.001). Circulating testosterone, Δ-4-androstenedione and Hirsutism Score (HS) significantly decreased in both groups. However, dehydro-epiandrosterone sulphate significantly decreased only in group B, and HS underwent a stronger reduction in group B (P < 0.001). At baseline, 39/56 (69.6%) patients met the diagnostic criteria for metabolic syndrome, but only one patient met these criteria after treatment. CONCLUSIONS: This study confirms the beneficial effects of metformin in PCOS patients. It also indicates that the addition of low-dose spironolactone induces a more marked reduction of clinical and biochemical hyperandrogenism as compared to metformin alone.

Thyroid cancer development and progression: emerging role of cancer stem cells.

Thyroid cancer is the most common endocrine malignancy. Although the majority of thyroid cancers are well differentiated and have a favorable prognosis, a minor proportion are poorly differentiated malignancies, which show an aggressive behavior and are refractory to conventional cancer treatments. The molecular mechanisms underlying thyroid development and progression are incompletely understood. Most of thyroid tumorigenesis models propose that thyroid cancer originates from the normal thyrocytes that, via the accumulation of genetic alterations, acquire a malignant phenotype and the ability to metastatize. However, recent progress in clarifying the molecular mechanisms of thyroid embryogenesis/development and the discovery of fetal/stem-like cells within the thyroid gland, have raised the possibility that thyroid cancer originates from progenitor/stem cells. These cells have the ability to self-renew and to undergo multilineage differentiation, and are resistant to common anticancer treatments. Thyroid progenitor/stem cells have been isolated from thyroid cancer and the normal counterpart. Further insights in the biology of these cells will open new perspectives in terms of prevention, diagnosis and therapy of thyroid cancers, especially those with an aggressive behaviour. More effective protocols for the identification and isolation of thyroid cancer stem cells will allow us to specifically and safely target these cells with the aim to definitely eradicate aggressive thyroid cancers.

p53 family proteins in thyroid cancer.

At variance with other human malignancies, p53 mutations are not frequent in thyroid cancer and are believed to be responsible mainly for cancer progression to poorly differentiated and aggressive phenotype. p63 and p73, two proteins with a high degree of homology with p53, are overexpressed in thyroid cancer, but their role in cancer initiation or progression is controversial. Regulation of p53 family protein function depends on: (1) the balance between the expression of transcriptionally active (p53, TAp63, and TAp73) and inactive isoforms (DeltaNp63 and DeltaNp73); (2) their interaction and competition at DNA-responsive elements; (3) their interaction with regulatory proteins, either inhibitory or activating. In thyroid cancer, therefore, although mutations of the p53 oncosuppressor protein family are rare, other mechanisms are present, including aberrant expression of p53 family dominant negative isoforms, up-regulation of inhibitory proteins, and functional inhibition of activating proteins. The overall result is a defective oncosuppressor activity. These inactivating mechanisms may be present in the early stages of thyroid cancer and in different cancer histotypes. A better understanding of this complex network may not only ameliorate our comprehension of cancer biology, but also open the possibility of innovative diagnostic procedures and the development of targeted therapies.

PPAR-γ agonists and their effects on IGF-I receptor signaling: Implications for cancer.

It is now well established that the development and progression of a variety of human malignancies are associated with dysregulated activity of the insulin-like growth factor (IGF) system. In this regard, promising drugs have been developed to target the IGF-I receptor or its ligands. These therapies are limited by the development of insulin resistance and compensatory hyperinsulinemia, which in turn, may stimulate cancer growth. Novel therapeutic approaches are, therefore, required. Synthetic PPAR-γ agonists, such as thiazolidinediones (TZDs), are drugs universally used as antidiabetic agents in patients with type 2 diabetes. In addition of acting as insulin sensitizers, PPAR-γ agonists mediate in vitro and in vivo pleiotropic anticancer effects. At least some of these effects appear to be linked with the downregulation of the IGF system, which is induced by the cross-talk of PPAR-γ agonists with multiple components of the IGF system signaling. As hyperinsulinemia is an emerging cancer risk factor, the insulin lowering action of PPAR-γ agonists may be expected to be also beneficial to reduce cancer development and/or progression. In light of these evidences, TZDs or other PPAR-γ agonists may be exploited in those tumors "addicted" to the IGF signaling and/or in tumors occurring in hyperinsulinemic patients.