Proteomic analysis of human thyroid cell lines reveals reduced nuclear localization of Mn-SOD in poorly differentiated thyroid cancer cells

Integrated Bioinformatics Analysis of Master Regulators in Anaplastic Thyroid Carcinoma

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive and rapidly lethal tumors. However, limited advances have been made to prolong the survival and to reduce the mortality over the last decades. Therefore, identifying the master regulators underlying ATC progression is desperately needed. In our present study, three datasets including GSE33630, GSE29265, and GSE65144 were retrieved from Gene Expression Omnibus with a total of 32 ATC samples and 78 normal thyroid tissues. A total of 1804 consistently changed differentially expressed genes (DEGs) were identified from three datasets. KEGG pathways enrichment suggested that upregulated DEGs were mainly enriched in ECM-receptor interaction, cell cycle, PI3K-Akt signaling pathway, focal adhesion, and p53 signaling pathway. Furthermore, key gene modules in PPI network were identified by Cytoscape plugin MCODE and they were mainly associated with DNA replication, cell cycle process, collagen fibril organization, and regulation of leukocyte migration. Additionally, TOP2A, CDK1, CCNB1, VEGFA, BIRC5, MAPK1, CCNA2, MAD2L1, CDC20, and BUB1 were identified as hub genes of the PPI network. Interestingly, module analysis showed that 8 out of 10 hub genes participated in Module 1 network and more than 70% genes of Module 2 consisted of collagen family members. Notably, transcription factors (TFs) regulatory network analysis indicated that E2F7, FOXM1, and NFYB were master regulators of Module 1, while CREB3L1 was the master regulator of Module 2. Experimental validation showed that CREB3L1, E2F7, and FOXM1 were significantly upregulated in ATC tissue and cell line when compared with normal thyroid group. In conclusion, the TFs regulatory network provided a more detail molecular mechanism underlying ATC occurrence and progression. TFs including E2F7, FOXM1, CREB3L1, and NFYB were likely to be master regulators of ATC progression, suggesting their potential role as molecular therapeutic targets in ATC treatment.

Management of controversial gastroenteropancreatic neuroendocrine tumour clinical situations with somatostatin analogues: results of a Delphi questionnaire panel from the NETPraxis program

BACKGROUND

There are clinical situations (CS) in which the use of somatostatin analogs (SSAs) in patients with neuroendocrine tumors (NET) is controversial due to lack of evidence. A Delphi study was conducted to develop common treatment guidelines for these CS, based on clinical practice and expert opinion of Spanish oncologists.

METHODS

A scientific committee identified 5 CS with a common core (c-c) [non-functioning NET, not susceptible of surgery/locoregional therapy, Ki67 < 10 % (except for CS5: >10 %), ECOG ≤ 2], and controversy regarding use of SSAs, and prepared a Delphi questionnaire of 48 treatment statements. Statements were rated on a 1 (completely disagree) to 9 (completely agree) scale. Responses were grouped by tertiles: 1-3: Disagreement, 4-6: Neutral, 7-9: Agreement. Consensus was reached when the responses of ≥2/3 participants were located in the same tertile as the median value of all reported responses for that statement.

RESULTS

Sixty five (81.2 %) of 80 invited oncologists with experience in the management of NETs answered a first round of the questionnaire and 57 (87.7 %) of those 65 answered a second round (mean age 43.5 years; 53.8 % women; median time of experience 9 years). Consensus was obtained in 42 (36 agreement and 6 disagreement) of the 48 statements (87.5 %). Regarding CS1 (Enteropancreatic NET, c-c, non-progressive in the last 3-6 months), overall, SSA treatment is recommended (a wait and see approach is anecdotal and reserved for fragile patients or with low tumor load or ki-67 < 2 %); CS2 (Pancreatic NET, c-c), overall, SSA monotherapy is recommended, except when high tumor load or tumor progression exists, where combination therapy would be considered; CS3 [Gastroenteropancreatic (GEP)-NET, c-c, in treatment with anti-proliferative dose of SSA and progressing], overall, SSA maintenance is recommended at the time of progression, with or without adding molecular targeted drugs; CS4 (GEP-NET, c-c, and negative octreoscan®), SSA in monotherapy is only considered in low-risk patients (low tumor load and Ki-67 < 5 %); CS5 [GEP-NET, c-c (ki67 > 10 %), and positive octreoscan®], monotherapy with SSA is mainly considered in patients with comorbidities.

CONCLUSION

Several recommendations regarding use of SSAs in controversial NET CS were reached in consensus and might be considered as treatment guideline.

Functional polymorphisms in antioxidant genes in Hurthle cell thyroid neoplasm - an association of GPX1 polymorphism and recurrent Hurthle cell thyroid carcinoma

Background

Hurthle cells of the thyroid gland are very rich in mitochondria and oxidative enzymes. As a high level oxidative metabolism may lead to higher level of oxidative stress and can be associated with an increased risk for cancer, we investigated whether common functional polymorphisms in antioxidant genes (SOD2, CAT, GPX, GSTP1, GSTM1 and GSTT1) are associated with the development or clinical course of Hurthle cell thyroid carcinoma (HCTC).

Methods

A retrospective study was performed in 139 patients treated by thyroid surgery for a Hurthle cell neoplasm. HCTC, Hurthle cell thyroid adenoma (HCTA) or Hurthle cell thyroid nodule (HCTN) were diagnosed by pathomorphology. DNA was extracted from cores of histologically confirmed normal tissue obtained from formalin-fixed paraffin-embedded specimens and genotyped for investigated polymorphisms. Logistic regression was used to compare genotype distributions between patient groups.

Results

HCTC, HCTA and HCTN were diagnosed in 53, 47 and 21 patients, respectively. Metastatic disease and recurrence of HCTC were diagnosed in 20 and 16 HCTC patients, respectively. Genotypes and allele frequencies of investigated polymorphisms did not deviate from Hardy-Weinberg equilibrium in patients with HCTC, HCTA and HCTN. Under the dominant genetic model we observed no differences in the genotype frequency distribution of the investigated polymorphisms when the HCTA and HCTN group was compared to the HCTC group for diagnosis of HCTC or for the presence of metastatic disease. However, GPX1 polymorphism was associated with the occurrence of recurrent disease (p = 0.040).

Conclusions

GPX1 polymorphism may influence the risk for recurrent disease in HCTC.

Differential proteomic and phenotypic behaviour of papillary and anaplastic thyroid cell lines

Thyroid carcinomas account for a minority of all malignant tumours but, after those of the gonads, they represent the most common forms of endocrine cancers. They include several types, among which the papillary thyroid cancer (PTC) and the anaplastic thyroid cancer (ATC) are the best known. The two hystotypes display significant biological and clinical differences: PTC is a well differentiated form of tumour with a high incidence and a good prognosis, while the ATC is less frequent but represents one of the most aggressive endocrine tumours with morphological features of an undifferentiated type. To date, as far as we know, no conclusive studies, useful to design arrays of molecular markers, have been published illustrating the phenotypic and proteomic differences between these two tumours. The aim of this work was to perform a comparative analysis of two thyroid cancer cell lines, derived respectively from papillary (BCPAP) and anaplastic (8505C) thyroid carcinomas. The comparative analysis included cell behaviour assays and proteomic analysis by 2D-PAGE and mass spectrometry. The results have highlighted a new proteomic signature for the anaplastic carcinoma-derived cells, consistent with their high proliferation rate, motility propensity and metabolic shift, in relation to the well-differentiated PTC cells.

Sunitinib exerts only limited effects on the proliferation and differentiation of anaplastic thyroid cancer cells

BACKGROUND

Novel molecularly targeted drugs are undergoing preclinical and clinical testing to assess their efficacy against refractory thyroid carcinomas. The multikinase inhibitor Sunitinib has been shown to inhibit the kinase activity of the RET oncogene and reduce proliferation in differentiated thyroid cancer cells harboring the RET/PTC rearrangement. In this study, we evaluated its effects in human cell lines derived from differentiated (TPC-1) and anaplastic (8505C, CAL-62, and C643) thyroid cancers.

METHODS

The cells exposed to various concentrations of Sunitinib were examined for: (1) cell viability and presence of apoptosis, analyzed by cell counts, MTT assay, trypan blue exclusion assay, western blotting, and immunofluorescence; (2) expression of cyclin D1 and phosphorylated and nonphosphorylated extracellular signal-regulated kinase (ERK) and Akt proteins, analyzed by western blotting; and (3) transcription of genes encoding thyrocyte differentiation markers (thyroid-stimulating hormone receptor, sodium/iodide symporter, thyroglobulin, and thyroperoxidase) and proangiogenic factors (vascular endothelial growth factor A, platelet-derived growth factors A and B), measured by quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Exposure to nanomolar concentrations of Sunitinib significantly reduced cell viability in only TPC-1 cells, and this effect was paralleled by reduction of cyclin D1 levels. Western blotting revealed reduced phosphorylation of ERK and Akt after 3 and 6 hours of drug exposure. In contrast, the growth of 8505C, CAL-62, and C-643 cells was significantly reduced only by micromolar concentrations of Sunitinib, mainly due to induced necrotic rather than apoptotic death. In these cells, Sunitinib exerted a few significant effects on the transcription of angiogenic factors or thyrocyte differentiation markers.

CONCLUSIONS

Sunitinib has little or no effect on the growth or differentiation of anaplastic thyroid cancer cells, thus suggesting that it is unlikely to be effective in the treatment of anaplastic thyroid cancer.

Genetic determinants of mitochondrial response to arsenic in yeast Saccharomyces cerevisiae

We have used yeast Saccharomyces cerevisiae as a tool to identify the importance of mitochondrial processes involved in arsenic-induced carcinogenicity in humans. We screened 466 single-gene knockout strains of yeast S. cerevisiae known to be involved in biogenesis of mitochondria for sodium arsenite (AsIII) and sodium arsenate (AsV) sensitivity. We identified 72 arsenite-sensitive and 81 arsenate-sensitive mutants. We categorized the identified mutants based on the various mitochondrial processes, including nucleic acid metabolism, oxidative phosphorylation, protein synthesis, and vacuolar acidification. We have identified 65 human orthologues to proteins involved in arsenite sensitivity and 3 human orthologues to arsenite resistance. Furthermore, 23 human orthologues to arsenate sensitivity and 20 human orthologues to arsenate-resistant proteins, including MSH3, COX10, GCSH, PPOX, and MTHFD1, were also identified. Using PathwayAssist software, we did cellular network analysis between identified mitochondrial proteins. Three types of interactions, (a) protein-protein interactions, (b) common transcriptional regulators, and (c) common target genes, were identified. We found that RTG (retrograde) genes involved in mitochondria-to-nucleus signaling regulate both arsenite sensitivity and resistance. Furthermore, our study revealed that ABF1, a multifunctional transcriptional factor, regulates genes involved in both arsenite and arsenate sensitivity and resistance. However, REB1 and RAP1 transcriptional regulators were common to only arsenate- and arsenite-sensitive genes, respectively. These studies indicate that multiple pathways involved in mitochondrial biogenesis protect yeast S. cerevisiae from arsenic-induced toxicity. Together, our studies suggest that evolutionary conserved mitochondrial networks identified in yeast S. cerevisiae must play an important role in arsenic-induced carcinogenesis in humans.

Growth inhibition of medullary thyroid carcinoma cells by pyrazolo-pyrimidine derivates

There is no effective treatment for recurrent or metastatic medullary thyroid carcinoma (MTC), a tumor arising from thyroid C-cells commonly presenting an inherited or acquired RET mutation. In this study we examined the sensitivity of two human MTC cell lines to novel pyrazolopyrimidine derivates, able to inhibit src-family tyrosine kinase activity. In TT cells [carrying the multiple endocrine neoplasia (MEN)2A Ret mutation Cys 634Trp] and MZ-CRC-1 cells (carrying the MEN2B RET mutation Met891Thr), one of these compounds, namely Si 34, determined a significant growth inhibitory effect (approximately 90% vs control for TT, 80% vs control for MZ-CRC-1) mainly due to enhanced cell mortality after a 6-day incubation. At concentrations that increased cell mortality, neither biochemical or morphological characteristics of apoptosis were detected in TT and MZCRC- 1 cells treated with Si 34. These results, when confirmed in other in vivo preclinical models, suggest that this novel tyrosine kinase inhibitor may be useful for the treatment of MTC.