Vía de señalización dependiente de la proteincinasa de activación mitogénica en el carcinoma papilar de tiroides. De las bases moleculares a la práctica clínica

Cross-Talk between Inflammatory Mediators and the Epithelial Mesenchymal Transition Process in the Development of Thyroid Carcinoma

There is strong association between inflammatory processes and their main metabolic mediators, such as leptin, adiponectin secretion, and low/high-density lipoproteins, with the cancer risk and aggressive behavior of solid tumors. In this scenario, cancer cells (CCs) and cancer stem cells (CSCs) have important roles. These cellular populations, which come from differentiated cells and progenitor stem cells, have increased metabolic requirements when it comes to maintaining or expanding the tumors, and they serve as links to some inflammatory mediators. Although the molecular mechanisms that are involved in these associations remain unclear, the two following cellular pathways have been suggested: 1) the mesenchymal-epithelial transition (MET) process, which permits the differentiation of adult stem cells throughout the acquisition of cell polarity and the adhesion to epithelia, as well to new cellular lineages (CSCs); and, 2) a reverse process, termed the epithelial-mesenchymal transition (EMT), where, in pathophysiological conditions (tissue injury, inflammatory process, and oxidative stress), the differentiated cells can acquire a multipotent stem cell-like phenotype. The molecular mechanisms that regulate both EMT and MET are complex and poorly understood. Especially, in the thyroid gland, little is known regarding MET/EMT and the role of CCs or CSCs, providing an exciting, new area of knowledge to be investigated. This article reviews the progress to date in research on the role of inflammatory mediators and metabolic reprogramming during the carcinogenesis process of the thyroid gland and the EMT pathways.

Inhibition of c-Met promoted apoptosis, autophagy and loss of the mitochondrial transmembrane potential in oridonin-induced A549 lung cancer cells

OBJECTIVE

Herein, inhibition of hepatocyte growth factor receptor, c-Met, significantly increased cytochrome c release and Bax/Bcl-2 ratio, indicating that c-Met played an anti-apoptotic role. The following experiments are to elucidate this anti-apoptotic mechanism, then the effect of c-Met on autophagy has also been discussed.

METHODS

Investigated was the influence of c-Met on apoptosis, autophagy and loss of mitochondrial transmembrane potential (Δψm), and the relevant proteins were examined.

KEY FINDINGS

First, we found that activation of extracellular signal-regulated kinase (ERK), p53 was promoted by c-Met interference. Subsequent studies indicated that ERK was the upstream effector of p53, and this ERK-p53 pathway mediated release of cytochrome c and up-regulation of Bax/Bcl-2 ratio. Secondly, the inhibition of c-Met augmented oridonin-induced loss of mitochondrial transmembrane potential (Δψm), resulting apoptosis. Finally, the inhibition of c-Met increased oridonin-induced A549 cell autophagy accompanied by Beclin-1 activation and conversion from microtubule-associated protein light chain 3 (LC3)-I to LC3-II. Activation of ERK-p53 was also detected in autophagy process and could be augmented by inhibition of c-Met. Moreover, suppression of autophagy by 3-methyladenine (3-MA) or small interfering RNA against Beclin-1 or Atg5 decreased oridonin-induced apoptosis. Inhibition of apoptosis by pan-caspase inhibitor (z-VAD-fmk) decreased oridonin-induced autophagy as well and Loss of Δψm also occurred during autophagic process.

CONCLUSION

Thus, inhibiting c-Met enhanced oridonin-induced apoptosis, autophagy and loss of Δψm in A549 cells.

Current and Future Perspectives in Thyroid Carcinoma Treatment

Thyroid nodules are a common clinical problem and evaluation with neck and thyroid ultrasound and fine-needle aspiration biopsy are the most accurate methods for evaluating and identifying those that require surgical resection. The surgical treatment of differentiated thyroid carcinoma is the most common and recommended approach. Post-operative ¹³¹I remnant ablation is used to eliminate the post-surgical thyroid remnant and may facilitate the early detection of recurrence. The conclusion of two important recent studies is that the use of recombinant human thyrotropin and low ¹³¹I dose, 30 mCi, for post-operative ablation may be sufficient for the management of low-risk thyroid cancer. Recently, multi-targeted kinase inhibitors have emerged as promising treatments for metastatic differentiated thyroid cancers based on mutation detection in samples from thyroid cancer. Motesanib, sorafenib, vandetanib, sunitinib, lenvatinib, imatinib and cabozantinib are multi-kinase inhibitors that have the ability of inhibiting the rearranged during transection (RET) and vascular endothelial growth factor receptor (VEGFR), and other kinases, and have been used in advanced differentiated thyroid carcinoma. By contrast, axitinib and pazopanib seem to act only as anti-angiogenic agents. Anaplastic thyroid carinoma is often advanced and metastatic at diagnosis. Patients with localised disease not amenable to surgical resection can be treated with adjuvant chemoradiotherapy.

Diagnostic and prognostic markers in differentiated thyroid cancer

The MAPK/ERK (mitogen-activated protein kinase/extracellular signal- regulated kinase signaling pathway) and PI3K/Akt (lipid kinase phoshoinositide-3-kinase signaling pathway) play an important role in transmission of cell signals through transduction systems as ligands, transmembrane receptors and cytoplasmic secondary messengers to cell nucleus, where they influence the expression of genes that regulate important cellular processes: cell growth, proliferation and apoptosis. The genes, coding the signaling cascade proteins (RET, RAS, BRAF, PI3K, PTEN, AKT), are mutated or aberrantly expressed in thyroid cancer derived from follicular thyroid cell. Genetic and epigenetic alternations, concerning MAPK/ERK and PI3K/Akt signaling pathways, contribute to their activation and interaction in consequence of malignant follicular cell transformation. Moreover, it is additionally pointed out that genetic, as well as epigenetic DNA changing via aberrant methylation of several tumor suppressor and thyroid-specific genes is associated with tumor aggressiveness, being a jointly responsible mechanism for thyroid tumorigenesis. In the present manuscript the currently developed diagnostic and prognostic genetic/epigenetic markers are presented; the understanding of this molecular mechanism provides access to novel molecular therapeutic strategies.

Gene expression profiling in human high-grade astrocytomas

Diffuse astrocytoma of (WHO grade II) has a tendency to progress spontaneously to anaplastic astrocytoma (WHO grade III) and/or glioblastoma (WHO grade IV). However, the molecular basis of astrocytoma progression is still poorly understood. In current study, an essential initial step toward this goal is the establishment of the taxonomy of tumors on the basis of their gene expression profiles. We have used gene expression profiling, unsupervised (hierarchal cluster (HCL) and principal component analysis (PCA)) and supervised (prediction analysis for microarrays (PAM)) learning methods, to demonstrate the presence of three distinct gene expression signatures of astrocytomas (ACMs), which correspond to diffuse or low-grade astrocytoma (WHO grade II), Anaplastic astrocytoma (WHO grade III) and Glioblastoma multiforme (WHO grade IV). We also demonstrate a 171 gene-based classifier that characterize the distinction between these pathologic/molecular subsets of astrocytomas. These results further define molecular subtypes of astrocytomas and may potentially be used to define potential targets and further refine stratification approaches for therapy. In addition, this study demonstrates that combining gene expression analysis with detailed annotated pathway and gene ontology (GO) category resources was applied to highly enriched normal and tumor population; it can yield an understanding of the critical biological mechanism of astrocytomas.

Clinical and pathological implications of concurrent autoimmune thyroid disorders and papillary thyroid cancer

Cooccurrences of chronic lymphocytic thyroiditis (CLT) and thyroid cancer (DTC) have been repeatedly reported. Both CLT and DTC, mainly papillary thyroid carcinoma (PTC), share some epidemiological and molecular features. In fact, thyroid lymphocytic inflammatory reaction has been observed in association with PTC at variable frequency, although the precise relationship between the two diseases is still debated. It also remains a matter of debate whether the association with a CLT or even an autoimmune disorder could influence the prognosis of PTC. A better understanding about clinical implications of autoimmunity in concurrent thyroid cancer could raise new insights of thyroid cancer immunotherapy. In addition, elucidating the molecular mechanisms involved in autoimmune disease and concurrent cancer allowed us to identify new therapeutic strategies against thyroid cancer. The objective of this article was to review recent literature on the association of these disorders and its potential significance.

[Usefulness of the immunohistochemical analysis of several molecular markers in the characterization of papillary thyroid carcinoma with initial lymph node metastasis]

INTRODUCTION AND OBJECTIVE

Regional lymph node metastases (LNM) are a common finding in papillary thyroid cancer (PTC). Approximately half of patients have LNM at diagnosis. The aim of this study was to analyze immunohistochemically the combined expression of different PTC-related molecules in order to identify cases with a tendency to show LNM.

PATIENTS AND METHODS

Thirty-five patients were included in the study. The patients were distributed in two groups. Group I included 19 patients with no histological evidence of LNM at diagnosis. Group II included 16 patients with histological evidence of cervical LNM. Samples were stained for RET/PTC, EGFR, p16(INk4a), p21(cip1), p27(kip1), BCL2, and pAKT.

RESULTS

Expression of p21(cip1), p27(kip1), p16(INk4a), Bcl-2, and pAKT showed no differences between the two groups. However, RET/PTC and EGFR expression showed significant differences: in both cases, staining was more frequent in patients with LNM. Simultaneous positivity of RET/PTC and EGFR was a discriminative marker in patients with LNM. Finally, the combination of RET/PTC negative, EGFR negative and p16(INk4a) negative was found in none of the patients with LNM but in nearly half of those in group I.

CONCLUSIONS

Immunohistochemical analysis of several molecular markers could be useful in the phenotypic characterization of PTC. Application of these markers could enhance diagnosis and improve the management of patients with thyroid cancer.