miR-148a inhibits self-renewal of thyroid cancer stem cells via repressing INO80 expression

Significance of miRNAs on the thyroid cancer progression and resistance to treatment with special attention to the role of cross-talk between signaling pathways

Thyroid cancer (TC) is the most prevalent endocrine malignant tumor. It has many types, the Papillary thyroid cancer (PTC)(most common and follicular thyroid carcinoma (FTC). Several risk factors have been associated with TC radiation exposure, autoimmunity, and genetics. Microribonucleic acids (miRNAs) are the most important genetic determinants of TC. They are small chains of nucleic acids that are able to inhibit the expression of several target genes. They could target several genes involved in TC proliferation, angiogenesis, apoptosis, development, and even resistance to therapy. Besides, they could influence the stemness of TC. Moreover, they could regulate several signaling pathways such as WNT/β-catenin, PI3K/AKT/mTOR axis, JAK/STAT, TGF- β, EGFR, and P53. Besides signaling pathways, miRNAs are also involved in the resistance of TC to major treatments such as surgery, thyroid hormone-inhibiting therapy, radioactive iodine, and adjuvant radiation. The stability and sensitivity of several miRNAs might be exploited as an approach for the usage of miRNAs as diagnostic and/or prognostic tools in TC.

Targeting Autophagy in Thyroid Cancer: EMT, Apoptosis, and Cancer Stem Cells

Autophagy is a highly conserved recycling process through which cellular homeostasis is achieved and maintained. With respect to cancer biology, autophagy acts as a double-edged sword supporting tumor cells during times of metabolic and therapeutic stress, while also inhibiting tumor development by promoting genomic stability. Accumulating evidence suggests that autophagy plays a role in thyroid cancer, acting to promote tumor cell viability and metastatic disease through maintenance of cancer stem cells (CSCs), supporting epithelial-to-mesenchymal transition (EMT), and preventing tumor cell death. Intriguingly, well-differentiated thyroid cancer is more prevalent in women as compared to men, though the underlying molecular biology driving this disparity has not yet been elucidated. Several studies have demonstrated that autophagy inhibitors may augment the anti-cancer effects of known thyroid cancer therapies. Autophagy modulation has become an attractive target for improving outcomes in thyroid cancer. This review aims to provide a comprehensive picture of the current knowledge regarding the role of autophagy in thyroid cancer, focusing on the potential mechanism(s) through which inhibition of autophagy may enhance cancer therapy and outcomes.

Inflammatory Components of the Thyroid Cancer Microenvironment: An Avenue for Identification of Novel Biomarkers

The incidence of thyroid cancer in the United States is on the rise with an appreciably high disease recurrence rate of 20-30%. Anaplastic thyroid cancer (ATC), although rare in occurrence, is an aggressive form of cancer with limited treatment options and bleak cure rates. This chapter uses discussions of in vitro models that are representative of papillary, anaplastic, and follicular thyroid cancer to evaluate the crosstalk between specific cells of the tumor microenvironment (TME), which serves as a highly heterogeneous realm of signaling cascades and metabolism that are associated with tumorigenesis. The cellular constituents of the TME carry out varying characteristic immunomodulatory functions that are discussed throughout this chapter. The aforementioned cell types include cancer-associated fibroblasts (CAFs), endothelial cells (ECs), and cancer stem cells (CSCs), as well as specific immune cells, including natural killer (NK) cells, dendritic cells (DCs), mast cells, T regulatory (Treg) cells, CD8+ T cells, and tumor-associated macrophages (TAMs). TAM-mediated inflammation is associated with a poor prognosis of thyroid cancer, and the molecular basis of the cellular crosstalk between macrophages and thyroid cancer cells with respect to inducing a metastatic phenotype is not yet known. The dynamic nature of the physiological transition to pathological metastatic phenotypes when establishing the TME encompasses a wide range of characteristics that are further explored within this chapter, including the roles of somatic mutations and epigenetic alterations that drive the genetic heterogeneity of cancer cells, allowing for selective advantages that aid in their proliferation. Induction of these proliferating cells is typically accomplished through inflammatory induction, whereby chronic inflammation sets up a constant physiological state of inflammatory cell recruitment. The secretions of these inflammatory cells can alter the genetic makeup of proliferating cells, which can in turn, promote tumor growth.This chapter also presents an in-depth analysis of molecular interactions within the TME, including secretory cytokines and exosomes. Since the exosomal cargo of a cell is a reflection and fingerprint of the originating parental cells, the profiling of exosomal miRNA derived from thyroid cancer cells and macrophages in the TME may serve as an important step in biomarker discovery. Identification of a distinct set of tumor suppressive miRNAs downregulated in ATC-secreted exosomes indicates their role in the regulation of tumor suppressive genes that may increase the metastatic propensity of ATC. Additionally, the high expression of pro-inflammatory cytokines in studies looking at thyroid cancer and activated macrophage conditioned media suggests the existence of an inflammatory TME in thyroid cancer. New findings are suggestive of the presence of a metastatic niche in ATC tissues that is influenced by thyroid tumor microenvironment secretome-induced epithelial to mesenchymal transition (EMT), mediated by a reciprocal interaction between the pro-inflammatory M1 macrophages and the thyroid cancer cells. Thus, targeting the metastatic thyroid carcinoma microenvironment could offer potential therapeutic benefits and should be explored further in preclinical and translational models of human metastatic thyroid cancer.

Disruption of Cell-Cell Communication in Anaplastic Thyroid Cancer as an Immunotherapeutic Opportunity

Thyroid cancer incidence is increasing at an alarming rate, almost tripling every decade. About 44,280 new cases of thyroid cancer (12,150 in men and 32,130 in women) are estimated to be diagnosed in 2021, with an estimated death toll of around 2200. Although most thyroid tumors are treatable and associated with a favorable outcome, anaplastic thyroid cancer (ATC) is extremely aggressive with a grim prognosis of 6-9 months post-diagnosis. A large contributing factor to this aggressive nature is that ATC is completely refractory to mainstream therapies. Analysis of the tumor microenvironment (TME) associated with ATC can relay insight to the pathological realm that encompasses tumors and aids in cancer progression and proliferation. The TME is defined as a complex niche that surrounds a tumor and involves a plethora of cellular components whose secretions can modulate the environment in order to favor tumor progression. The cellular heterogeneity of the TME contributes to its dynamic function due to the presence of both immune and nonimmune resident, infiltrating, and interacting cell types. Associated immune cells discussed in this chapter include macrophages, dendritic cells (DCs), natural killer (NK) cells, and tumor-infiltrating lymphocytes (TILs). Nonimmune cells also play a role in the establishment and proliferation of the TME, including neuroendocrine (NE) cells, adipocytes, endothelial cells (ECs), mesenchymal stem cells (MSCs), and fibroblasts. The dynamic nature of the TME contributes greatly to cancer progression.Recent work has found ATC tissues to be defined by a T cell-inflamed "hot" tumor immune microenvironment (TIME) as evidenced by presence of CD3+ and CD8+ T cells. These tumor types are amenable to immune checkpoint blockade (ICB) therapy. This therapeutic avenue, as of 2021, has remained unexplored in ATC. New studies should seek to explore the therapeutic feasibility of a combination therapy, through the use of a small molecule inhibitor with ICB in ATC. Screening of in vitro model systems representative of papillary, anaplastic, and follicular thyroid cancer explored the expression of 29 immune checkpoint molecules. There are higher expressions of HVEM, BTLA, and CD160 in ATC cell lines when compared to the other TC subtypes. The expression level of HVEM was more than 30-fold higher in ATC compared to the others, on average. HVEM is a member of tumor necrosis factor (TNF) receptor superfamily, which acts as a bidirectional switch through interaction with BTLA, CD160, and LIGHT, in a cis or trans manner. Given the T cell-inflamed hot TIME in ATC, expression of HVEM on tumor cells was suggestive of a possibility for complex crosstalk of HVEM with inflammatory cytokines. Altogether, there is emerging evidence of a T cell-inflamed TIME in ATC along with the expression of immune checkpoint proteins HVEM, BTLA, and CD160 in ATC. This can open doors for combination therapies using small molecule inhibitors targeting downstream effectors of MAPK pathway and antagonistic antibodies targeting the HVEM/BTLA axis as a potentially viable therapeutic avenue for ATC patients. With this being stated, the development of adaptive resistance to targeted therapies is inevitable; therefore, using a combination therapy that targets the TIME can serve as a preemptive tactic against the characteristic therapeutic resistance that is seen in ATC. The dynamic nature of the TME, including the immune cells, nonimmune cells, and acellular components, can serve as viable targets for combination therapy in ATC. Understanding the complex interactions of these associated cells and the paradigm in which their secretions and components can serve as immunomodulators are critical points of understanding when trying to develop therapeutics specifically tailored for the anaplastic thyroid carcinoma microenvironment.

Poorly Differentiated and Anaplastic Thyroid Cancer: Insights into Genomics, Microenvironment and New Drugs

Simple Summary

In the last decades, many researchers produced promising data concerning genetics and tumor microenvironment of poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC). They are trying to tear the veil covering these orphan cancers, suggesting new therapeutic weapons as single or combined therapies.

Abstract

PDTC and ATC present median overall survival of 6 years and 6 months, respectively. In spite of their rarity, patients with PDTC and ATC represent a significant clinical problem, because of their poor survival and the substantial inefficacy of classical therapies. We reviewed the newest findings about genetic features of PDTC and ATC, from mutations occurring in DNA to alterations in RNA. Therefore, we describe their tumor microenvironments (both immune and not-immune) and the interactions between tumor and neighboring cells. Finally, we recapitulate how this upcoming evidence are changing the treatment of PDTC and ATC.

Non-Coding RNAs: Uncharted Mediators of Thyroid Cancer Pathogenesis

Thyroid cancer is the most prevalent malignancy of the endocrine system and the ninth most common cancer globally. Despite the advances in the management of thyroid cancer, there are critical issues with the diagnosis and treatment of thyroid cancer that result in the poor overall survival of undifferentiated and metastatic thyroid cancer patients. Recent studies have revealed the role of different non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) that are dysregulated during thyroid cancer development or the acquisition of resistance to therapeutics, and may play key roles in treatment failure and poor prognosis of the thyroid cancer patients. Here, we systematically review the emerging roles and molecular mechanisms of ncRNAs that regulate thyroid tumorigenesis and drug response. We then propose the potential clinical implications of ncRNAs as novel diagnostic and prognostic biomarkers for thyroid cancer.

Thyroid Cancer and Circadian Clock Disruption

Thyroid cancer (TC) represents the most common malignancy of the endocrine system, with an increased incidence across continents attributable to both improvement of diagnostic procedures and environmental factors. Among the modifiable risk factors, insulin resistance might influence the development of TC. A relationship between circadian clock machinery disfunction and TC has recently been proposed. The circadian clock machinery comprises a set of rhythmically expressed genes responsible for circadian rhythms. Perturbation of this system contributes to the development of pathological states such as cancer. Several clock genes have been found deregulated upon thyroid nodule malignant transformation. The molecular mechanisms linking circadian clock disruption and TC are still unknown but could include insulin resistance. Circadian misalignment occurring during shift work, jet lag, high fat food intake, is associated with increased insulin resistance. This metabolic alteration, in turn, is associated with a well-known risk factor for TC i.e., hyperthyrotropinemia, which could also be induced by sleep disturbances. In this review, we describe the mechanisms controlling the circadian clock function and its involvement in the cell cycle, stemness and cancer. Moreover, we discuss the evidence supporting the link between circadian clockwork disruption and TC development/progression, highlighting its potential implications for TC prevention, diagnosis and therapy.

The Possible Role of Cancer Stem Cells in the Resistance to Kinase Inhibitors of Advanced Thyroid Cancer

Target therapy with various kinase inhibitors (KIs) has been extended to patients with advanced thyroid cancer, but only a subset of these compounds has displayed efficacy in clinical use. However, after an initial response to KIs, dramatic disease progression occurs in most cases. With the discovery of cancer stem cells (CSCs), it is possible to postulate that thyroid cancer resistance to KI therapies, both intrinsic and acquired, may be sustained by this cell subtype. Indeed, CSCs have been considered as the main drivers of metastatic activity and therapeutic resistance, because of their ability to generate heterogeneous secondary cell populations and survive treatment by remaining in a quiescent state. Hence, despite the impressive progress in understanding of the molecular basis of thyroid tumorigenesis, drug resistance is still the major challenge in advanced thyroid cancer management. In this view, definition of the role of CSCs in thyroid cancer resistance may be crucial to identifying new therapeutic targets and preventing resistance to anti-cancer treatments and tumor relapse. The aim of this review is to elucidate the possible role of CSCs in the development of resistance of advanced thyroid cancer to current anti-cancer therapies and their potential implications in the management of these patients.

Non-Coding RNAs and Nucleosome Remodeling Complexes: An Intricate Regulatory Relationship

Eukaryotic genomes are pervasively transcribed, producing both coding and non-coding RNAs (ncRNAs). ncRNAs are diverse and a critical family of biological molecules, yet much remains unknown regarding their functions and mechanisms of regulation. ATP-dependent nucleosome remodeling complexes, in modifying chromatin structure, play an important role in transcriptional regulation. Recent findings show that ncRNAs regulate nucleosome remodeler activities at many levels and that ncRNAs are regulatory targets of nucleosome remodelers. Further, a series of recent screens indicate this network of regulatory interactions is more expansive than previously appreciated. Here, we discuss currently described regulatory interactions between ncRNAs and nucleosome remodelers and contextualize their biological functions.

The Emerging Roles of ATP-Dependent Chromatin Remodeling Complexes in Pancreatic Cancer

Pancreatic cancer is an aggressive cancer with low survival rates. Genetic and epigenetic dysregulation has been associated with the initiation and progression of pancreatic tumors. Multiple studies have pointed to the involvement of aberrant chromatin modifications in driving tumor behavior. ATP-dependent chromatin remodeling complexes regulate chromatin structure and have critical roles in stem cell maintenance, development, and cancer. Frequent mutations and chromosomal aberrations in the genes associated with subunits of the ATP-dependent chromatin remodeling complexes have been detected in different cancer types. In this review, we summarize the current literature on the genomic alterations and mechanistic studies of the ATP-dependent chromatin remodeling complexes in pancreatic cancer. Our review is focused on the four main subfamilies: SWItch/sucrose non-fermentable (SWI/SNF), imitation SWI (ISWI), chromodomain-helicase DNA-binding protein (CHD), and INOsitol-requiring mutant 80 (INO80). Finally, we discuss potential novel treatment options that use small molecules to target these complexes.

Roles of the INO80 and SWR1 Chromatin Remodeling Complexes in Plants

Eukaryotic genes are packed into a dynamic but stable nucleoprotein structure called chromatin. Chromatin-remodeling and modifying complexes generate a dynamic chromatin environment that ensures appropriate DNA processing and metabolism in various processes such as gene expression, as well as DNA replication, repair, and recombination. The INO80 and SWR1 chromatin remodeling complexes (INO80-c and SWR1-c) are ATP-dependent complexes that modulate the incorporation of the histone variant H2A.Z into nucleosomes, which is a critical step in eukaryotic gene regulation. Although SWR1-c has been identified in plants, plant INO80-c has not been successfully isolated and characterized. In this review, we will focus on the functions of the SWR1-c and putative INO80-c (SWR1/INO80-c) multi-subunits and multifunctional complexes in Arabidopsis thaliana. We will describe the subunit compositions of the SWR1/INO80-c and the recent findings from the standpoint of each subunit and discuss their involvement in regulating development and environmental responses in Arabidopsis.

Role of miRNA-Regulated Cancer Stem Cells in the Pathogenesis of Human Malignancies

Recent biomedical discoveries have revolutionized the concept and understanding of carcinogenesis, a complex and multistep phenomenon which involves accretion of genetic, epigenetic, biochemical, and histological changes, with special reference to MicroRNAs (miRNAs) and cancer stem cells (CSCs). miRNAs are small noncoding molecules known to regulate expression of more than 60% of the human genes, and their aberrant expression has been associated with the pathogenesis of human cancers and the regulation of stemness features of CSCs. CSCs are the small population of cells present in human malignancies well-known for cancer resistance, relapse, tumorigenesis, and poor clinical outcome which compels the development of novel and effective therapeutic protocols for better clinical outcome. Interestingly, the role of miRNAs in maintaining and regulating the functioning of CSCs through targeting various oncogenic signaling pathways, such as Notch, wingless (WNT)/β-Catenin, janus kinases/ signal transducer and activator of transcription (JAK/STAT), phosphatidylinositol 3-kinase/ protein kinase B (PI3/AKT), and nuclear factor kappa-light-chain-enhancer of activated B (NF-kB), is critical and poses a huge challenge to cancer treatment. Based on recent findings, here, we have documented the regulatory action or the underlying mechanisms of how miRNAs affect the signaling pathways attributed to stemness features of CSCs, such as self-renewal, differentiation, epithelial to mesenchymal transition (EMT), metastasis, resistance and recurrence etc., associated with the pathogenesis of various types of human malignancies including colorectal cancer, lung cancer, breast cancer, head and neck cancer, prostate cancer, liver cancer, etc. We also shed light on the fact that the targeted attenuation of deregulated functioning of miRNA related to stemness in human carcinogenesis could be a viable approach for cancer treatment.

LncRNA PTCSC3 affects drug resistance of anaplastic thyroid cancer through STAT3/INO80 pathway

BACKGROUND

LncRNA PTCSC3 is a tumor suppressor in thyroid cancer, and its role in drug resistance of anaplastic thyroid cancer (ATC) to chemotherapy drug doxorubicin was investigated in this study.

METHODS

Expression of RNA and protein was analyzed by qRT-PCR and western blot, respectively. Flow cytometry was used to analyze the expression rate of CD133⁺ cells. The endogenous expression of related genes was modulated by recombinant plasmids and cell transfection. Combination condition and interaction between PTCSC3 and STAT3 were determined by RIP and RNA pull-down assay, respectively. MTT assay was performed to detect cytotoxicity. Chromatin immunoprecipitation was conducted to identify interactions between STAT3 and DNA promoter of INO80.

RESULTS

LncRNA PTCSC3 was low-expressed in ATC tissues and cells. Over-expressed PTCSC3 inhibited the drug resistance of ATC to doxorubicin. PTCSC3 negatively regulated STAT3, and STAT3 promoted expression of INO80. PTCSC3 regulated INO80 through STAT3. PTCSC3 suppressed stem cells properties and drug resistance of ATC to doxorubicin.

CONCLUSION

LncRNA PTCSC3 inhibits INO80 expression by negatively regulating STAT3, and thereby attenuating drug resistance of ATC to chemotherapy drug doxorubicin.

The INO80 remodeller in transcription, replication and repair

The accessibility of eukaryotic genomes to the action of enzymes involved in transcription, replication and repair is maintained despite the organization of DNA into nucleosomes. This access is often regulated by the action of ATP-dependent nucleosome remodellers. The INO80 class of nucleosome remodellers has unique structural features and it is implicated in a diverse array of functions, including transcriptional regulation, DNA replication and DNA repair. Underlying these diverse functions is the catalytic activity of the main ATPase subunit, which in the context of a multisubunit complex can shift nucleosomes and carry out histone dimer exchange. In vitro studies showed that INO80 promotes replication fork progression on a chromatin template, while in vivo it was shown to facilitate replication fork restart after stalling and to help evict RNA polymerase II at transcribed genes following the collision of a replication fork with transcription. More recent work in yeast implicates INO80 in the general eviction and degradation of nucleosomes following high doses of oxidative DNA damage. Beyond these replication and repair functions, INO80 was shown to repress inappropriate transcription at promoters in the opposite direction to the coding sequence. Here we discuss the ways in which INO80's diverse functions help maintain genome integrity.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.

Microrna-136 promotes proliferation and invasion ingastric cancer cells through Pten/Akt/P-Akt signaling pathway

Gastric cancer is the fourth most common cancer and the second most frequent cause of cancer-associated mortality in the world. Previous studies have revealed that expression levels of microRNAs (miRNAs) are associated with the initiation and progression of several types of cancer, including gastric cancer. Previous studies have demonstrated that the abnormal expression of miRNA-136 may serve a function in the progression of several types of human cancer. However, the expression pattern of miR-136, its functions and underlying molecular mechanisms in gastric cancer remain unresolved. In the present study, it was revealed that the expression of miR-136 was aberrantly up regulated in gastric cancer tissues and cell lines. The suppression of miR-136 was able to inhibit proliferation and invasion in gastric cancer cell lines. Furthermore, phosphatase and tensin homolog (PTEN) was identified as a direct target gene of miR-136 in gastric cancer. PTEN was under expressed in gastric cancer tissues compared with non-tumor gastric tissues, and PTEN expression was negatively correlated with miR-136 expression. Furthermore, PTEN overexpression mimics the effects of miR-136 knockdown on gastric cancer cells. Additionally, miR-136 under expression decreased phospho-(p) AKT expression, but did not affect AKT expression in gastric cancer cells. In conclusion, the data of the present study suggest that miR-136 acts as an oncogene in gastric cancer via regulation of the PTEN/AKT/p-AKT signaling pathway and may potentially serve as a novel therapeutic target for the treatment of gastric cancer.