Thiocoraline alters neuroendocrine phenotype and activates the Notch pathway in MTC-TT cell line

The role of MAPK, notch and Wnt signaling pathways in papillary thyroid cancer: Evidence from a systematic review and meta-analyzing microarray datasets employing bioinformatics knowledge and literature

Papillary thyroid cancer (PTC) is a prevalent kind of thyroid cancer (TC), with the risk of metastasis increasing faster than any other malignancy. So, understanding the role of PTC in pathogenesis requires studying the various gene expressions to find out which particular molecular biomarkers will be helpful. The authors conducted a comprehensive search on the PubMed microarray database and a meta-analysis approach on the remaining ones to determine the differentially expressed genes between PTC and normal tissues, along with the analyses of overall survival (OS) and recurrence-free survival (RFS) rates in patients with PTC. We considered the associated genes with MAPK, Wnt, and Notch signaling pathways. Two GEO datasets have been included in this research, considering inclusion and exclusion criteria. Nineteen genes were found to have higher differences through the meta-analysis procedure. Among them, ten genes were upregulated, and nine genes were downregulated. The expression of 19 genes was examined using the GEPIA2 database, and the Kaplan-Meier plot statistics were used to analyze RFS and the OS rates. We discovered seven significant genes with the validation: PRICKLE1, KIT, RPS6KA5, GADD45B, FGFR2, FGF7, and DTX4. To further explain these findings, it was discovered that the mRNA expression levels of these seven genes and the remaining 12 genes were shown to be substantially linked with the results of the experimental literature investigations on the PTC. Our research found nineteen panels of genes that could be involved in the PTC progression and metastasis and the immune system infiltration of these cancers.

Identification of TNIK as a novel potential drug target in thyroid cancer based on protein druggability prediction

Thyroid cancer is a common endocrine malignancy; however, surgery remains its primary treatment option. A novel targeted drug for the development and application of targeted therapy in thyroid cancer treatment remain underexplored.We obtained RNA sequence data of thyroid cancer from The Cancer Genome Atlas database and identified differentially expressed genes (DEGs). Then, we constructed co-expression network with DEGs and combined it with differentially methylation analysis to screen the key genes in thyroid cancer. PockDrug-Server, an online tool, was applied to predict the druggability of the key genes. Finally, we constructed protein-protein interaction (PPI) network to observe potential targeted drugs for thyroid cancer.We identified 3 genes correlated with altered DNA methylation level and oncogenesis of thyroid cancer. According to the druggable analysis and PPI network, we predicted TRAF2 and NCK-interacting protein kinase (TNIK) sever as the drug targeted for thyroid cancer. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis indicated that genes in protein-protein interaction network of TNIK enriched in mitogen-activated protein kinase signaling pathway. For drug repositioning, we identified a targeted drug of genes in PPI network.Our study provides a bioinformatics method for screening drug targets and provides a theoretical basis for thyroid cancer targeted therapy.

Natural Cyclopeptides as Anticancer Agents in the Last 20 Years

Cyclopeptides or cyclic peptides are polypeptides formed by ring closing of terminal amino acids. A large number of natural cyclopeptides have been reported to be highly effective against different cancer cells, some of which are renowned for their clinical uses. Compared to linear peptides, cyclopeptides have absolute advantages of structural rigidity, biochemical stability, binding affinity as well as membrane permeability, which contribute greatly to their anticancer potency. Therefore, the discovery and development of natural cyclopeptides as anticancer agents remains attractive to academic researchers and pharmaceutical companies. Herein, we provide an overview of anticancer cyclopeptides that were discovered in the past 20 years. The present review mainly focuses on the anticancer efficacies, mechanisms of action and chemical structures of cyclopeptides with natural origins. Additionally, studies of the structure-activity relationship, total synthetic strategies as well as bioactivities of natural cyclopeptides are also included in this article. In conclusion, due to their characteristic structural features, natural cyclopeptides have great potential to be developed as anticancer agents. Indeed, they can also serve as excellent scaffolds for the synthesis of novel derivatives for combating cancerous pathologies.

Notch Signaling in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system with a steadily rising incidence. The term "thyroid cancer" encompasses a spectrum of subtypes, namely papillary thyroid cancer, follicular thyroid cancer, anaplastic thyroid cancer, and medullary thyroid cancer. Each subtype differs histopathologically and in degrees of cellular differentiation, which may be in part due to signaling of the Notch pathway. The Notch pathway is an evolutionarily conserved signal transduction mechanism that regulates cell proliferation, differentiation, survival, stem cell maintenance, embryonic and adult development, epithelial-mesenchymal transition, and angiogenesis. Its role in cancer biology is controversial, as it has been shown to play both an oncogenic and tumor-suppressive role in many different types of cancers. This discordance holds true for each subtype of thyroid cancer, indicating that Notch signaling is likely cell type and context dependent. Whether oncogenic or not, Notch signaling has proven to be significantly involved in the tumorigenesis of thyroid cancer and has thus earned interest as a therapeutic target. Advancement in the understanding of Notch signaling in thyroid cancer holds great promise for the development of novel treatment strategies to benefit patients.

Marine Natural Products with High Anticancer Activities

This review covers recent literature from 2012-2019 concerning 170 marine natural products and their semisynthetic analogues with strong anticancer biological activities. Reports that shed light on cellular and molecular mechanisms and biological functions of these compounds, thus advancing the understanding in cancer biology are also included. Biosynthetic studies and total syntheses, which have provided access to derivatives and have contributed to the proper structure or stereochemistry elucidation or revision are mentioned. The natural compounds isolated from marine organisms are divided into nine groups, namely: alkaloids, sterols and steroids, glycosides, terpenes and terpenoids, macrolides, polypeptides, quinones, phenols and polyphenols, and miscellaneous products. An emphasis is placed on several drugs originating from marine natural products that have already been marketed or are currently in clinical trials.

Thiocoraline mediates drug resistance in MCF-7 cells via PI3K/Akt/BCRP signaling pathway

Thiocoraline, a depsipeptide bisintercalator with potent antitumor activity, was first isolated from marine actinomycete Micromonospora marina. It possesses an intense toxicity to MCF-7 cells at nanomolar concentrations in a dose-dependent manner evaluated by MTT assay and crystal violet staining. We established a human breast thiocoraline-resistant cancer subline of MCF-7/thiocoraline (MCF-7/T) to investigate the expression variation of breast cancer resistance proteins (BCRP) and its subsequent influence on drug resistance. Colony-forming assay showed that the MCF-7 cells proliferated faster than the MCF-7/T cells in vitro. Western blot analysis demonstrated that thiocoraline increased the phosphorylation of Akt. Additionally, the sensitivity of tumor cells to thiocoraline was reduced with a concurrent rise in phosphorylation level of Akt and of BCRP expression.These studies indicated that thiocoraline probably mediated the drug resistance via PI3K/Akt/BCRP signaling pathway. MK-2206 dihydrochloride, a selective phosphorylation inhibitor of Akt, significantly decreased MCF-7 cell viability under exposure to thiocoraline compared to the control. However, it was not obviously able to decrease MCF-7/T cell viability when cells were exposed to thiocoraline.

Signaling cascades in thyroid cancer: Increasing the armory of archers to hit bullseye

Thyroid cancer is a multifaceted and therapeutically challenging disease and rapidly accumulating experimentally verified findings have considerably improve our understanding of the molecular mechanisms which underlie its development. Substantial fraction of information has been added into existing landscape of molecular oncology and we have started to develop a sharper understanding of the underlying mechanisms of thyroid cancer. Wealth of information demystified different intracellular signaling cascades which are frequently deregulated in thyroid cancer. In vitro assays and xenografted mice based studies have helped us to identify drug targets and different synthetic and natural products are currently being tested to effectively treat thyroid cancer. Cabozantinib and vandetanib have been approved to treat medullary thyroid cancer (MTC) and two agents (lenvatinib and sorafenib) are also being used to treat radioactive-iodine refractory differentiated thyroid cancer. This review comprehensively summarizes most recent advancements in our knowledge related to dysregulated intracellular signaling cascades in thyroid cancer and how different proteins can be therapeutically exploited. (1) We discuss how loss of TRAIL mediated apoptosis occurred in thyroid cancer cells and how different strategies can be used to restore apoptosis in resistant cancer cells; (2) We provide detailed account of seemingly opposite roles of NOTCH signaling in thyroid cancers; (3) TGF/SMAD mediated signaling also needs detailed research because of context dependent role in thyroid cancer. Researchers have only begun to scratch the surface of how TGF signaling works in thyroid cancer and metastasis; and (4) Role of SHH signaling in thyroid cancer stem cells is also well appreciated and targeting of SHH pathway will be an important aspect in treatment of thyroid cancer. Better concepts and improved knowledge will be helpful for clinicians in getting a step closer to individualized medicine.

Antineoplastic effects of histone deacetylase inhibitors in neuroendocrine cancer cells are mediated through transcriptional regulation of Notch1 by activator protein 1

Notch signaling is minimally active in neuroendocrine (NE) cancer cells. While histone deacetylase inhibitors (HDACi) suppress NE cancer growth by inducing Notch, the molecular mechanism underlying this interplay has not yet been defined. NE cancer cell lines BON, H727, and MZ-CRC-1 were treated with known HDACi Thailadepsin-A (TDP-A) and valproic acid (VPA), and Notch1 mRNA expression was measured with RT-PCR. Truncated genomic fragments of the Notch1 promotor region fused with luciferase reporter were used to identify the potential transcription factor (TF) binding site. The key regulatory TF was identified with the electrophoretic mobility shift assay (EMSA). The effect of HDACi on Notch1 level was determined before and after silencing the TF. TDP-A and VPA induced Notch1 mRNA in a dose-dependent manner. A functional DNA motif at -80 to -52 from the Notch1 start codon responsible for the HDACi-dependent Notch1 induction was identified. Mutation of this core sequence failed to induce luciferase activity despite HDACi treatment. EMSA showed the greatest gel shift with AP-1 in nuclear extracts. Knockdown of AP-1 significantly attenuated the effect of HDACi on Notch1 induction. Interestingly, AP-1 transfection did not alter Notch1 level, suggesting that AP-1 is necessary but insufficient for HDACi activation of Notch1. Therefore, AP-1 is the TF that binds to a specific transcription-binding site within the Notch1 promotor region to trigger Notch1 transcription. Elucidating the HDACi activation mechanism may lead to the development of novel therapeutic options against NE cancers and facilitate the identification of clinical responders and prevent adverse effects.

Histone deacetylase inhibitor thailandepsin-A activates Notch signaling and suppresses neuroendocrine cancer cell growth in vivo

Novel therapies for neuroendocrine (NE) cancers are desperately needed as they frequently present as metastatic disease and cause debilitating symptoms by secreting excessive hormones. Induction of Notch isoforms has a tumor suppressive effect in NE cancer cell lines, and we have observed that histone deacetylase inhibitors (HDACi) potently activate Notch. In this study, we describe the potential for Burkholderia thailandensis-derived class I HDACi thailandepsin A (TDP-A) as a Notch activator and therapeutic agent against NE cancer. IC₅₀ for TDP-A was determined to be 4-6 nM in NE cancer cell lines (BON, MZ-CRC-1, and TT) without cytotoxicity to lung fibroblasts. The binding characteristics of TDP-A to its target HDAC1 was examined using bioluminescence resonance energy transfer (BRET). Western blot and flow cytometry analysis showed that TDP-A induces cell cycle arrest and apoptosis in a dose-dependent manner. TDP-A dose-dependently activated the Notch pathway as measured by increasing functional CBF1-luciferase reporter signal and mRNA and protein expressions of Notch isoforms, which were attenuated by pretreatment with γ-secretase inhibitor DAPT. Furthermore, TDP-A lead to changes in expression level of downstream targets of Notch pathway and reduced expression of NE cancer markers. An in vivo study demonstrated that TDP-A suppressed NE cancer progression. These results show that TDP-A, as a Notch activator, is a promising agent against NE cancers.

Tumor-suppressor role of Notch3 in medullary thyroid carcinoma revealed by genetic and pharmacological induction

Notch1-3 are transmembrane receptors that appear to be absent in medullary thyroid cancer (MTC). Previous research has shown that induction of Notch1 has a tumor-suppressor effect in MTC cell lines, but little is known about the biologic consequences of Notch3 activation for the progression of the disease. We elucidate the role of Notch3 in MTC by genetic (doxycycline-inducible Notch3 intracellular domain) and pharmacologic [AB3, novel histone deacetylase (HDAC) inhibitor] approaches. We find that overexpression of Notch3 leads to the dose-dependent reduction of neuroendocrine tumor markers. In addition, Notch3 activity is required to suppress MTC cell proliferation, and the extent of growth repression depends on the amount of Notch3 protein expressed. Moreover, activation of Notch3 induces apoptosis. The translational significance of this finding is highlighted by our observation that MTC tumors lack active Notch3 protein and reinstitution of this isoform could be a therapeutic strategy to treat patients with MTC. We demonstrate, for the first time, that overexpression of Notch3 in MTC cells can alter malignant neuroendocrine phenotype in both in vitro and in vivo models. In addition, our study provides a strong rationale for using Notch3 as a therapeutic target to provide novel pharmacologic treatment options for MTC.

Thiocoraline activates the Notch pathway in carcinoids and reduces tumor progression in vivo

Carcinoids are slow-growing neuroendocrine tumors (NETs) that are characterized by hormone overproduction; surgery is currently the only option for treatment. Activation of the Notch pathway has previously been shown to have a role in tumor suppression in NETs. The marine-derived thiodepsipeptide thiocoraline was investigated in vitro in two carcinoid cell lines (BON and H727). Carcinoid cells treated with nanomolar concentrations of thiocoraline resulted in a decrease in cell proliferation and an alteration of malignant phenotype evidenced by decrease of NET markers, ASCL-1, CgA, and NSE. Western blot analysis demonstrated the activation of Notch1 on the protein level in BON cells. Additionally, thiocoraline activated downstream Notch targets HES1, HES5, and HEY2. Thiocoraline effectively suppressed carcinoid cell growth by promoting cell cycle arrest in BON and H727 cells. An in vivo study demonstrated that thiocoraline, formulated with polymeric micelles, slowed carcinoid tumor progression. Thus, the therapeutic potential of thiocoraline, which induced activation of the Notch pathway, in carcinoid tumors was demonstrated.

Biosynthetic modularity rules in the bisintercalator family of antitumor compounds

Diverse actinomycetes produce a family of structurally and biosynthetically related non-ribosomal peptide compounds which belong to the chromodepsipeptide family. These compounds act as bisintercalators into the DNA helix. They give rise to antitumor, antiparasitic, antibacterial and antiviral bioactivities. These compounds show a high degree of conserved modularity (chromophores, number and type of amino acids). This modularity and their high sequence similarities at the genetic level imply a common biosynthetic origin for these pathways. Here, we describe insights about rules governing this modular biosynthesis, taking advantage of the fact that nowadays five of these gene clusters have been made public (thiocoraline, triostin, SW-163 and echinomycin/quinomycin). This modularity has potential application for designing and producing novel genetic engineered derivatives, as well as for developing new chemical synthesis strategies. These would facilitate their clinical development.