The role of iodine and delta-iodolactone in growth and apoptosis of malignant thyroid epithelial cells and breast cancer cells.

OBJECTIVE: As we previously demonstrated, the inhibitory effect of iodine on thyroid cell growth is mediated by iodolactones, especially 6-iodo-5-hydroxy-eicosatrienoic acid (delta-iodolactone). In this communication we compare the effect of iodide, molecular iodine and delta-iodolactone on growth inhibition and apoptosis on three human thyroid carcinoma cell lines (B-CPAP cells, FTC-133 cells and 8505C cells) as well as on human breast cancer cells (MCF 7). METHODS: Thyroid carcinoma cells were cultured in Dulbecco's modified Eagle's medium (DMEM) and MCF 7 cells in Rowswell Park Memorial Institute (RPMI) culture medium, both containing 10% (v/v) Fetal Calf Serum (FCS), until they were confluent. Around 2000 cells were then distributed in 12-well plates and grown for 48 h in either DMEM (thyroid cancer cells) or in RPMI medium (MCF 7 cells) both containing 5% FCS. Thereafter, different concentrations of iodide, iodine or delta-iodolactone were added for 24 h. Growth rate was estimated by cell counting in a Coulter Counter adapted for epithelial cells. Apoptosis was determined by a mitochondrial potential assay. RESULTS: The growth rate of B-CPAP cells was unaffected by iodide, but was reduced by high concentreations of molecular iodine (100 and 500 microM). However, delta-iodolactone significantly reduced cell proliferation already with low concentrations (5 microM and 10 microM) and further in a dose-dependent manner up to 82%. FTC-133 and 8505C cells were unaffected by iodide, iodine or delta-iodolactone. In contrast, in MCF 7 cells, molecular iodine (100 microM) inhibited growth from 100% to 83% but delta-iodolactone (1, 5 and 10 microM) dose-dependently decreased growth rate from 100% to 82% and 62%, respectively. The inhibition of growth was through apoptosis, and not necrosis, as the amount of apoptotic cells corresponded to the growth inhibition. CONCLUSION: delta-Iotaodolactone seems to be the main iodocompound which can inhibit growth and induce apoptosis in B-CPAP cells as well as in MCF 7 breast cancer cells.

Diverse Responses of Autoantibodies to the Angiotensin II Type 1 Receptor in Primary Aldosteronism.

Primary aldosteronism is a common form of endocrine hypertension mainly caused by a unilateral aldosterone-producing adenoma (APA) or bilateral adrenal hyperplasia (BAH). AT1R-Abs (autoantibodies to the angiotensin II type 1 receptor) have been reported in patients with disorders associated with hypertension. Our objective was to assess AT1R-Ab levels in patients with primary aldosteronism (APA, n=40 and BAH, n=40) relative to patients with primary hypertension (n=40), preeclampsia (n=23), and normotensive individuals (n=25). AT1R-Abs in whole sera were measured using 2 different ELISAs which gave contrasting results. A functional cell-based assay was used to quantify activation of the AT1R (angiotensin II type 1 receptor) using whole sera or affinity-purified antibodies in the absence or presence of losartan (a specific AT1R antagonist). Serum samples from all groups displayed different levels of AT1R activation with different responses to losartan. Patients with BAH displayed higher losartan-independent affinity-isolated agonistic AT1R-Ab levels compared with patients with APA (P<0.01) and with normotensive individuals (P<0.0001). In patients with APA, BAH, and primary hypertension combined, higher aldosterone-to-renin ratios and lower plasma renin concentrations were associated with higher compared with lower agonistic AT1R-Ab levels. In patients with primary aldosteronism, higher AT1R-Ab activity was associated with an increased likelihood of a diagnosis of BAH compared with APA and with the presence of adrenal hyperplasia detected by computed tomography. Taken together, these data suggest that agonistic AT1R-Abs may have a functional role in a subgroup of patients with primary aldosteronism.

Synergistic Highly Potent Targeted Drug Combinations in Different Pheochromocytoma Models Including Human Tumor Cultures.

There are no officially approved therapies for metastatic pheochromocytomas apart from ultratrace 131I-metaiodbenzylguanidine therapy, which is approved only in the United States. We have, therefore, investigated the antitumor potential of molecular-targeted approaches in murine pheochromocytoma cell lines [monocyte chemoattractant protein (MPC)/monocyte chemoattractant protein/3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)], immortalized mouse chromaffin Sdhb-/- cells, three-dimensional pheochromocytoma tumor models (MPC/MTT spheroids), and human pheochromocytoma primary cultures. We identified the specific phosphatidylinositol-3-kinase α inhibitor BYL719 and the mammalian target of rapamycin inhibitor everolimus as the most effective combination in all models. Single treatment with clinically relevant doses of BYL719 and everolimus significantly decreased MPC/MTT and Sdhb-/- cell viability. A targeted combination of both inhibitors synergistically reduced MPC and Sdhb-/- cell viability and showed an additive effect on MTT cells. In MPC/MTT spheroids, treatment with clinically relevant doses of BYL719 alone or in combination with everolimus was highly effective, leading to a significant shrinkage or even a complete collapse of the spheroids. We confirmed the synergism of clinically relevant doses of BYL719 plus everolimus in human pheochromocytoma primary cultures of individual patient tumors with BYL719 attenuating everolimus-induced AKT activation. We have thus established a method to assess molecular-targeted therapies in human pheochromocytoma cultures and identified a highly effective combination therapy. Our data pave the way to customized combination therapy to target individual patient tumors.

Dose-related influence of sodium selenite on apoptosis in human thyroid follicles in vitro induced by iodine, EGF, TGF-beta, and H2O2.

Apoptosis of thyroid follicular cells is induced by high doses of iodide, epidermal growth factor (EGF), transforming growth factor-beta (TGF-beta), as well as H2O2 and might be attenuated by antioxidants. Therefore, we examined the apoptotic index induced by these substances in selenium-treated vs untreated human thyroid follicular cells. Reconstituted human thyroid follicles were incubated with sodium selenite (10 or 100 nM) for 72 h; controls received none. The follicles were then distributed to 24-well plates and incubated with potassium iodide (5, 10, or 20 nM), EGF (5 ng/mL), TGF-beta (5 ng/mL), or H2O2 (100 muM). Apoptosis was determined by a mitochondrial potential assay and the number of apoptotic cells counted by two independent, experienced technicians and the glutathione peroxidase (GPx) activity was determined. Asignificant increase of apoptic cells was obtained in control thyroid follicles treated with iodine (5, 10, or 20 microM), thyroidstimulating hormone (TSH) 1, or 10 mU/mL in combination with 5 and 10 microM iodine, EGF (5 ng/mL) and TGF-beta (5 ng/mL), or H2O2 (100 microM) (p < 0.001). In contrast, in thyroid follicles preincubated with 10 or 100 nM sodium selenite, the apoptototic index was identical to the basal rate. In H2O2-treated follicles, the apoptotic index was still significantly elevated but 50% lower compared to control cells. The GPx activity increased from 1.4 +/- 0.2 to 2.25 +/- 0.4 mU/microg DNA with 10 nMselenite and 2.6 + 0.4 mU/microg DNA with 100 nM selenite. Sodium selenite might increase the antioxidative potential in human thyroid follicles in vitro and therefore diminish the apoptosis induced by TGF-beta, EGF, iodide, and even H2O2.