Activated Ras oncogene induces DNA-damage response by triggering reactive oxygen species (ROS) production and this is critical for oncogene-induced senescence. Until now, little connections between oncogene expression, ROS-generating NADPH oxidases and DNA-damage response have emerged from different studies. Here we report that H-RasV12 positively regulates the NADPH oxidase system NOX4-p22phox that produces H2O2. Knocking down the NADPH oxidase with small interference RNA decreases H-RasV12-induced DNA-damage response detected by γ-H2A.X foci analysis. Using HyPer, a specific probe for H2O2, we detected an increase in H2O2 in the nucleus correlated with NOX4-p22phox perinuclear localization. DNA damage response can be caused not only by H-RasV12-driven accumulation of ROS but also by a replicative stress due to a sustained oncogenic signal. Interestingly, NOX4 downregulation by siRNA abrogated H-RasV12 regulation of CDC6 expression, an essential regulator of DNA replication. Moreover, senescence markers, such as senescence-associated heterochromatin foci, PML bodies, HP1β foci and p21 expression, induced under H-RasV12 activation were decreased with NOX4 inactivation. Taken together, our data indicate that NADPH oxidase NOX4 is a critical mediator in oncogenic H-RasV12-induced DNA-damage response and subsequent senescence.

Thyroid cancer is the most common endocrine cancer. The discovery of new biomarkers for thyroid cancer has significantly improved the understanding of the molecular pathogenesis of thyroid cancer, thus allowing more personalized treatments for patients with thyroid cancer. Most of the recently discovered targeted therapies inhibit the known oncogenic mechanisms in thyroid cancer initiation and progression such as MAPK pathway, PI3K/Akt-mTOR pathways, or VEGF. Despite the significant advances in molecular testing and the discoveries of new and promising therapeutics, effective treatments for advanced and metastatic, iodine-refractory thyroid cancer are still lacking. Here, we aim to summarize the current understanding of the genetic alterations and the dysregulated pathways in thyroid cancer and to discuss the most recent targeted therapies and immunotherapy for advanced thyroid cancer with a promising anti-tumor activity and clinical benefit.

Purpose Mitochondrial glycerophosphate dehydrogenase (mGPDH) is the key enzyme connecting oxidative phosphorylation (OXPHOS) and glycolysis as well as a target of the antidiabetic drug metformin (MF) in the liver. There are no data on the expression and role of mGPDH as a metformin target in cancer. In this study, we evaluated mGPDH as a potential target of metformin in thyroid cancer and investigated its contribution in thyroid cancer metabolism. Experimental design We analyzed mGPDH expression in 253 thyroid cancer and normal tissues by immunostaining and examined its expression and localization in thyroid cancer-derived cell lines (FTC133, BCPAP) by confocal microscopy. The effects of metformin on mGPDH expression were determined by qRT-PCR and western blot. Seahorse analyzer was utilized to assess the effects of metformin on OXPHOS and glycolysis in thyroid cancer cells. We analyzed the effects of metformin on tumor growth and mGPDH expression in metastatic thyroid cancer mouse models. Results We show for the first time that mGPDH is overexpressed in thyroid cancer compared with normal thyroid. We demonstrate that mGPDH regulates human thyroid cancer cell growth and OXPHOS rate in vitro. Metformin treatment is associated with downregulation of mGPDH expression and inhibition of OXPHOS in thyroid cancer in vitro. Cells characterized by high mGPDH expression are more sensitive to OXPHOS-inhibitory effects of metformin in vitro and growth inhibitory effects of metformin in vitro and in vivo. Conclusion Our study established mGPDH as a novel regulator of thyroid cancer growth and metabolism that can be effectively targeted by metformin.

Background Nonfunctioning adrenal incidentalomas are common and many patients undergo adrenalectomy to exclude adrenocortical carcinoma (ACC). Recent studies have shown dysregulated microRNA expression in ACC. The objective of this study was to determine the feasibility and diagnostic accuracy of measuring serum microRNAs in patients with benign and malignant adrenocortical tumors. Method Five microRNAs were selected from microRNA profiling studies in ACC (miR-let-7d, -34a, -195, -214, and 483-5p). Total microRNA was extracted from serum samples in patients with malignant and benign adrenal neoplasms. MicroRNAs levels were measured by quantitative RT-PCR and normalized to miR-16. To determine if microRNAs were secreted from ACC cells, we measured microRNA levels in culture. Results Serum samples from 22 patients with cortical adenomas and 17 patients with ACC were analyzed and all 5 microRNAs were detected. We found higher levels of miR-34a(p=0.001) and miR-483-5p(p=0.011) in patients with ACC. The AUC was 0.81 for miR-34a and 0.74 for miR-438-5p. MiR-34a and miR-483-5p levels in ACC cells were higher in the supernatant at 48 hours as compared to intracellular levels. Conclusions We show dysregulated microRNAs in ACC are detectable in human serum samples. MiR-34a and miR-483-5p are candidate serum biomarkers for distinguishing between benign and malignant adrenocortical tumors.

Background Hyperparathyroidism-jaw tumor syndrome (HPT-JT) is a rare autosomal dominant disease secondary to germline inactivating mutations of the tumor suppressor gene HRPT2/CDC73. The aim of the present study is to determine the optimal surgical approach to parathyroid disease in patients with HPT-JT. Method A retrospective analysis of clinical and genetic features, parathyroid operative outcomes, and disease outcomes in seven unrelated HPT-JT families. Results Seven families had five distinct germline HRPT2/CDC73 mutations. Sixteen affected family members (median age of 30.7 years) were diagnosed with primary hyperparathyroidism. Fifteen of the 16 patients underwent preoperative tumor localization studies and uncomplicated bilateral neck exploration at initial operation - all were in biochemical remission at most recent follow up. 31% of patients had multiglandular involvement. 37.5% of patients developed parathyroid carcinoma (median overall survival 8.9 years; median follow-up 7.4 years). Long-term follow-up showed 20% of patients had recurrent primary hyperparathyroidism. Conclusions Given the high risk of malignancy and multiglandular involvement in our cohort, we recommend bilateral neck exploration and en-bloc resection of parathyroid tumors suspicious for cancer and life-long postoperative follow-up.

The microRNAs (miRNAs) are small non-coding RNA comprising approximately 19–25 nucleotides. miRNAs can act as tumour suppressors or oncogenes, and aberrant expression of miRNAs has been reported in several human cancers and has been associated with cancer initiation and progression. Recent evidence suggests that miRNAs play a major role in thyroid carcinogenesis. In this review, we summarize the role of miRNAs in thyroid cancer and describe the oncogenic or tumour suppressor function of miRNAs as well as their clinical utility as prognostic or diagnostic markers in thyroid cancer.

The expression and function of miR-145 in thyroid cancer is unknown. We evaluated the expression and function of miR-145 in thyroid cancer and its potential clinical application as a biomarker. We found that the expression of miR-145 is significantly downregulated in thyroid cancer as compared with normal. Overexpression of miR-145 in thyroid cancer cell lines resulted in: decreased cell proliferation, migration, invasion, VEGF secretion, and E-cadherin expression. miR-145 overexpression also inhibited the PI3K/Akt pathway and directly targeted AKT3. In vivo, miR-145 overexpression decreased tumor growth and metastasis in a xenograft mouse model, and VEGF secretion. miR-145 inhibition in normal primary follicular thyroid cells decreased the expression of thyroid cell differentiation markers. Analysis of indeterminate fine-needle aspiration samples showed miR-145 had a 92% negative predictive value for distinguishing benign from malignant thyroid nodules. Circulating miR-145 levels were significantly higher in patients with thyroid cancer and showed a venous gradient. Serum exosome extractions revealed that miR-145 is secreted. Our findings suggest that miR-145 is a master regulator of thyroid cancer growth, mediates its effect through the PI3K/Akt pathway, is secreted by the thyroid cancer cells, and may serve as an adjunct biomarker for thyroid cancer diagnosis.

Anaplastic thyroid cancer (ATC) is one of the most lethal human malignancies, but its genetic drivers remain little understood. In this study, we report losses in expression of the miRNA miR30a, which is downregulated in ATC compared with differentiated thyroid cancer and normal tissue. miR30a downregulation was associated with advanced differentiated thyroid cancer and higher mortality. Mechanistically, we found miR30a decreased cellular invasion and migration, epithelialmesenchymal transition marker levels, lysyl oxidase (LOX) expression, and metastatic capacity. LOX was identified as a direct target of miR30a that was overexpressed in ATC and associated with advanced differentiated thyroid cancer and higher mortality rate. Consistent with its role in other cancers, we found that LOX inhibited cell proliferation, cellular invasion, and migration and metastasis in vitro and in vivo. Together, our findings establish a critical functional role for miR30a downregulation in mediating LOX upregulation and thyroid cancer progression, with implications for LOX targeting as a rational therapeutic strategy in ATC. Cancer Res; 75(2); 367-77.Ó2014 AACR.