Dihydrotanshinone I exhibits antitumor effects via ß-catenin downregulation in papillary thyroid cancer cell lines.

Thyroid cancer is the most common endocrine carcinoma and, among its different subtypes, the papillary subtype (PTC) is the most frequent. Generally, PTCs are well differentiated, but a minor percentage of PTCs are characterized by a worse prognosis and more aggressive behavior. Phytochemicals, naturally found in plant products, represent a heterogeneous group of bioactive compounds that can interfere with cell proliferation and the regulation of the cell cycle, taking part in multiple signaling pathways that are often disrupted in tumor initiation, proliferation, and progression. In this work, we focused on 15,16-dihydrotanshinone I (DHT), a tanshinone isolated from Salvia miltiorrhiza Bunge (Danshen). We first evaluated DHT biological effect on PTC cells regarding cell viability, colony formation ability, and migration capacity. All of these parameters were downregulated by DHT treatment. We then investigated gene expression changes after DHT treatment by performing RNA-seq. The analysis revealed that DHT significantly reduced the Wnt signaling pathway, which plays a role in various diseases, including cancer. Finally, we demonstrate that DHT treatment decreases protein levels of ß-catenin, a final effector of canonical Wnt signaling pathway. Overall, our data suggest a possible use of this nutraceutical as an adjuvant in the treatment of aggressive papillary thyroid carcinoma.

A bird's eye view on the use of whole exome sequencing in rare congenital ophthalmic diseases.

Phenotypic and genotypic heterogeneity in congenital ocular diseases, especially in anterior segment dysgenesis (ASD), have created challenges for proper diagnosis and classification of diseases. Over the last decade, genomic research has indeed boosted our understanding in the molecular basis of ASD and genes associated with both autosomal dominant and recessive patterns of inheritance have been described with a wide range of expressivity. Here we describe the molecular characterization of a cohort of 162 patients displaying isolated or syndromic congenital ocular dysgenesis. Samples were analyzed with diverse techniques, such as direct sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing (WES), over 20 years. Our data reiterate the notion that PAX6 alterations are primarily associated with ASD, mostly aniridia, since the majority of the cohort (66.7%) has a pathogenic or likely pathogenic variant in the PAX6 locus. Unexpectedly, a high fraction of positive samples (20.3%) displayed deletions involving the 11p13 locus, either partially/totally involving PAX6 coding region or abolishing its critical regulatory region, underlying its significance. Most importantly, the use of WES has allowed us to both assess variants in known ASD genes (i.e., CYP1B1, ITPR1, MAB21L1, PXDN, and PITX2) and to identify rarer phenotypes (i.e., MIDAS, oculogastrointestinal-neurodevelopmental syndrome and Jacobsen syndrome). Our data clearly suggest that WES allows expanding the analytical portfolio of ocular dysgenesis, both isolated and syndromic, and that is pivotal for the differential diagnosis of those conditions in which there may be phenotypic overlaps and in general in ASD.

GSK2801 Reverses Paclitaxel Resistance in Anaplastic Thyroid Cancer Cell Lines through MYCN Downregulation.

Anaplastic thyroid cancer (ATC) is a very rare, but extremely aggressive form of thyroid malignancy, responsible for the highest mortality rate registered for thyroid cancer. Treatment with taxanes (such as paclitaxel) is an important approach in counteracting ATC or slowing its progression in tumors without known genetic aberrations or those which are unresponsive to other treatments. Unfortunately, resistance often develops and, for this reason, new therapies that overcome taxane resistance are needed. In this study, effects of inhibition of several bromodomain proteins in paclitaxel-resistant ATC cell lines were investigated. GSK2801, a specific inhibitor of BAZ2A, BAZ2B and BRD9, was effective in resensitizing cells to paclitaxel. In fact, when used in combination with paclitaxel, it was able to reduce cell viability, block the ability to form colonies in an anchor-independent manner, and strongly decrease cell motility. After RNA-seq following treatment with GSK2801, we focused our attention on MYCN. Based on the hypothesis that MYCN was a major downstream player in the biological effects of GSK2801, we tested a specific inhibitor, VPC-70619, which showed effective biological effects when used in association with paclitaxel. This suggests that the functional deficiency of MYCN determines a partial resensitization of the cells examined and, ultimately, that a substantial part of the effect of GSK2801 results from inhibition of MYCN expression.

Role of m6A RNA Methylation in Thyroid Cancer Cell Lines.

N6-methyladenosine (m6A) is the most abundant internal modification of RNA in eukaryotic cells, and, in recent years, it has gained increasing attention. A good amount of data support the involvement of m6A modification in tumorigenesis, tumor progression, and metastatic dissemination. However, the role of this RNA modification in thyroid cancer still remains poorly investigated. In this study, m6A-related RNA methylation profiles are compared between a normal thyroid cell line and different thyroid cancer cell lines. With this approach, it was possible to identify the different patterns of m6A modification in different thyroid cancer models. Furthermore, by silencing METTL3, which is the main player in the RNA methylation machinery, it was possible to evaluate the impact of m6A modification on gene expression in an anaplastic thyroid cancer model. This experimental approach allowed us to identify DDI2 as a gene specifically controlled by the m6A modification in anaplastic thyroid cancer cell lines. Altogether, these data are a proof of concept that RNA methylation widely occurs in thyroid cancer cell models and open a way forward in the search for new molecular patterns for diagnostic discrimination between benign and malignant lesions.

Enantioselective Cytotoxicity of Chiral Diphosphine Ruthenium(II) Complexes Against Cancer Cells.

The chiral cationic complex [Ru(η1 -OAc)(CO)((R,R)-Skewphos)(phen)]OAc (2R ), isolated from reaction of [Ru(η1 -OAc)(η2 -OAc)(R,R)-Skewphos)(CO)] (1R ) with phen, reacts with NaOPiv and KSAc affording [RuX(CO)((R,R)-Skewphos)(phen)]Y (X=Y=OPiv 3R ; X=SAc, Y=OAc 4R ). The corresponding enantiomers 2S -4S have been obtained from 1S containing (S,S)-Skewphos. Reaction of 2R and 2S with (S)-cysteine and NaPF6 at pH=9 gives the diastereoisomers [Ru((S)-Cys)(CO)(PP)(phen)]PF6 (PP=(R,R)-Skewphos 2R -Cys; (S,S)-Skewphos 2S -Cys). The DFT energetic profile for 2R with (S)-cysteine in H2 O indicates that aquo and hydroxo species are involved in formation of 2R -Cys. The stability of the ruthenium complexes in 0.9 % w/v NaCl solution, PBS and complete DMEM medium, as well as their n-octanol/water partition coefficient (logP), have been evaluated. The chiral complexes show high cytotoxic activity against SW1736, 8505 C, HCT-116 and A549 cell lines with EC50 values of 2.8-0.04 µM. The (R,R)-Skewphos derivatives show higher cytotoxicity compared to their enantiomers, 4R (EC50 =0.04 µM) being 14 times more cytotoxic than 4S against the anaplastic thyroid cancer 8505 C cell line.

Effects of Dihydrotanshinone I on Proliferation and Invasiveness of Paclitaxel-Resistant Anaplastic Thyroid Cancer Cells.

ATC is a very rare, but extremely aggressive form of thyroid malignancy, responsible for the highest mortality rate registered for thyroid cancer. In patients without known genetic aberrations, the current treatment is still represented by palliative surgery and systemic mono- or combined chemotherapy, which is often not fully effective for the appearance of drug resistance. Comprehension of the mechanisms involved in the development of the resistance is therefore an urgent issue to suggest novel therapeutic approaches for this very aggressive malignancy. In this study, we created a model of anaplastic thyroid cancer (ATC) cells resistant to paclitaxel and investigated the characteristics of these cells by analyzing the profile of gene expression and comparing it with that of paclitaxel-sensitive original ATC cell lines. In addition, we evaluated the effects of Dihydrotanshinone I (DHT) on the viability and invasiveness of paclitaxel-resistant cells. ATC paclitaxel-resistant cells highlighted an overexpression of ABCB1 and a hyper-activation of the NF-κB compared to sensitive cells. DHT treatment resulted in a reduction of viability and clonogenic ability of resistant cells. Moreover, DHT induces a decrement of NF-κB activity in SW1736-PTX and 8505C-PTX cells. In conclusion, to the best of our knowledge, the results of the present study are the first to demonstrate the antitumor effects of DHT on ATC cells resistant to Paclitaxel in vitro.

Dihydrotanshinone exerts antitumor effects and improves the effects of cisplatin in anaplastic thyroid cancer cells.

Anaplastic thyroid cancer (ATC) is the most aggressive type of thyroid cancer and is responsible for 20­50% of thyroid cancer­associated deaths. The absence of response to conventional treatments makes the search for novel therapeutics a clinical challenge. In the present study, the effects of 15,16­dihydrotanshinone I (DHT), a tanshinone extracted from Salvia miltiorrhiza Bunge (Danshen), which has previously been shown to possess anticancer activity, were examined in two human ATC cell lines. DHT significantly reduced cell viability, which was coupled with an increase in apoptosis. DHT administration also reduced the colony­forming ability and proliferation of these cells in soft agar and downregulated the expression of epithelial­to­mesenchymal transition­related genes. In addition, DHT significantly reduced MAD2 expression, a target of HuR with a relevant role in ATC. Finally, cotreatment with cisplatin and DHT has a greater effect on cell viability than each compound alone. In conclusion, to the best of our knowledge, the present study is the first to demonstrate that DHT exerts antitumor effects on ATC cells by reducing MAD2 expression levels. Moreover, a synergistic effect of DHT with cisplatin was shown. Further in vivo studies are required to assess this phytochemical compound as a potential adjuvant for the treatment of ATC.

Longitudinal Dynamics of Circulating Tumor Cells and Circulating Tumor DNA for Treatment Monitoring in Metastatic Breast Cancer.

Liquid biopsy-based biomarkers, including circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), are increasingly important for the characterization of metastatic breast cancer (MBC). The aim of the study was to explore CTCs and ctDNA dynamics to better understand their potentially complementary role in describing MBC. METHODS: The study retrospectively analyzed 107 patients with MBC characterized with paired CTCs and ctDNA assessments and a second prospective cohort, which enrolled 48 patients with MBC. CTCs were immunomagnetically isolated and ctDNA was quantified and then characterized through next-generation sequencing in the retrospective cohort and droplet digital polymerase chain reaction in the prospective cohort. Matched pairs variations at baseline, at evaluation one (EV1), and at progression were tested through the Wilcoxon test. The prognostic role of ctDNA parameters was also investigated. RESULTS: Mutant allele frequency (MAF) had a significant decrease between baseline and EV1 and a significant increase between EV1 and progression. Number of detected alterations steadily increased across timepoints, CTCs enumeration (nCTCs) significantly increased only between EV1 and progression. MAF dynamics across the main altered genes was then investigated. Plasma DNA yield did not vary across timepoints both in the retrospective cohort and in the prospective cohort, while the short fragments fraction showed a potential role as a prognostic biomarker. CONCLUSION: nCTCs and ctDNA provide complementary information about prognosis and treatment benefit. Although nCTCs appeared to assess tumor biology rather than tumor burden, MAF may be a promising biomarker for the dynamic assessment of treatment response and resistance.

A paternally inherited 1.4 kb deletion of the 11p15.5 imprinting center 2 is associated with a mild familial Silver-Russell syndrome phenotype.

The Silver-Russell syndrome (SRS) is a rare disorder characterized by heterogeneous clinical features, including growth retardation, typical facial dysmorphisms, and body asymmetry. Genetic alterations causative of SRS mostly affect imprinted genes located on chromosomes 7 or 11. Hypomethylation of the Imprinting Center 1 (IC1) of the chromosome 11p15.5 is the most common cause of SRS, while the Imprinting Center 2 (IC2) has been more rarely involved. Specifically, maternally inherited 11p15.5 deletions including the IC2 have been associated with the Beckwith-Wiedemann Syndrome (BWS), while paternal deletions with a variable spectrum of phenotypes. Here, we describe the case of a girl with a mild SRS phenotype associated with a paternally inherited 1.4 kb deletion of IC2. The father of the proband inherited the deletion from his mother and showed normal growth, while the paternal grandmother had the deletion on her paternal chromosome and exhibited short stature. Together with previous findings obtained in mouse and humans, our data support the notion that deletion of the paternal copy of IC2 can cause SRS.

Plasma-Based Longitudinal Evaluation of ESR1 Epigenetic Status in Hormone Receptor-Positive HER2-Negative Metastatic Breast Cancer.

BACKGROUND: Endocrine therapy (ET) is the mainstay of treatment for hormone receptor-positive human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer; however, adaptive mechanisms emerge in about 25-30% of cases through alterations in the estrogen receptor ligand-binding domain, with a consequent ligand-independent estrogen receptor activity. Epigenetic-mediated events are less known and potentially involved in alternative mechanisms of resistance. The aim of this study was to test the feasibility of estrogen receptor 1 (ESR1) epigenetic characterization through liquid biopsy and to show its potential longitudinal application for an early ET sensitivity assessment. METHODS: A cohort of 49 women with hormone receptor-positive HER2-negative MBC was prospectively enrolled and characterized through circulating tumor DNA using methylation-specific droplet digital PCR (MS-ddPCR) before treatment start (BL) and after 3 months concomitantly with computed tomography (CT) scan restaging (EV1). ESR1 epigenetic status was defined by assessing the methylation of its main promoters (promA and promB). The most established cell-free tumor DNA (ctDNA) factors associated with ET resistance [ESR1 and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) mutations] were assessed through next-generation sequencing. Associations were tested through Mann-Whitney U test, matched pairs variations through Wilcoxon signed rank test, and survival was analyzed by log-rank test. RESULTS: The ET backbone was mainly based on aromatase inhibitors (AIs) (70.83%) in association with CDK4/6 inhibitors (93.75%). Significantly lower promA levels at baseline were observed in patients with liver metastases (P = 0.0212) and in patients with ESR1 mutations (P = 0.0091). No significant impact on PFS was observed for promA (P = 0.3777) and promB (P = 0.7455) dichotomized at the median while a ≥2-fold increase in promB or in either promA or promB at EV1 resulted in a significantly worse prognosis (respectively P = 0.0189, P = 0.0294). A significant increase at EV1 was observed for promB among patients with PIK3CA mutation (P = 0.0173). A trend was observed for promB in ESR1 wild-type patients and for promA in the ESR1 mutant subgroup. CONCLUSION: The study proofed the concept of an epigenetic characterization strategy based on ctDNA and is capable of being integrated in the current clinical workflow to give useful insights on treatment sensitivity.

Critical Involvement of Calcium-Dependent Cytosolic Phospholipase A2α in Aortic Valve Interstitial Cell Calcification.

The involvement of calcium-dependent cytosolic phospholipase A2α (cPLA2α) in aortic valve calcification is not exhaustively elucidated. Here, cPLA2α expression in aortic valve interstitial cell (AVIC) pro-calcific cultures simulating either metastatic or dystrophic calcification was estimated by qPCR, Western blotting, and counting of cPLA2α-immunoreactive cells, with parallel ultrastructural examination of AVIC calcific degeneration. These evaluations also involved pro-calcific AVIC cultures treated with cPLA2α inhibitor dexamethasone. cPLA2α over-expression resulted for both types of pro-calcific AVIC cultures. Compared to controls, enzyme content was found to increase by up to 300% and 186% in metastatic and dystrophic calcification-like cultures, respectively. Increases in mRNA amounts were also observed, although they were not as striking as those in enzyme content. Moreover, cPLA2α increases were time-dependent and strictly associated with mineralization progression. Conversely, drastically lower levels of enzyme content resulted for the pro-calcific AVIC cultures supplemented with dexamethasone. In particular, cPLA2α amounts were found to decrease by almost 88% and 48% in metastatic and dystrophic calcification-like cultures, respectively, with mRNA amounts showing a similar trend. Interestingly, these drastic decreases in cPLA2α amounts were paralleled by drastic decreases in mineralization degrees, as revealed ultrastructurally. In conclusion, cPLA2α may be regarded as a crucial co-factor contributing to AVIC mineralization in vitro, thus being an attractive potential target for designing novel therapeutic strategies aimed to counteract onset or progression of calcific aortic valve diseases.

Cationic carboxylate and thioacetate ruthenium(ii) complexes: synthesis and cytotoxic activity against anaplastic thyroid cancer cells.

The cationic acetate ruthenium complex [Ru(η1-OAc)(CO)(dppb)(phen)]OAc (1) is easily prepared in 83% yield from [Ru(η1-OAc)(η2-OAc)(CO)(dppb)] (dppb = 1,4-bis(diphenylphosphino)butane) and 1,10-phenanthroline (phen) in MeOH. The derivative 1 undergoes easy substitution of the coordinated acetate by reaction with NaOPiv, KSAc, and KSCN in MeOH, affording the corresponding complexes [RuX(CO)(dppb)(phen)]X (X = OPiv, 2; SAc, 3; and NCS, 4), whereas its reaction with NaCl and NH4PF6 affords [RuCl(CO)(dppb)(phen)]PF6 (5). Carboxylate complexes 1 and 2 show high solubility in water, enabling easy exchange of the coordinated carboxylate by water and other ligands (CH3CN, glutathione). Cationic complexes 1-5, compared to Cisplatin, display a strong cell viability decrease in two human anaplastic thyroid cancer cell lines (SW1736 and 8505C), ranging from 3.10 µM to 0.09 µM EC50 values. The most active compounds 1-3 show a marked increment of apoptosis and decrease of cancer cell aggressiveness, making them promising candidates for further evaluation studies.

BAZ1B is a candidate gene responsible for hypothyroidism in Williams syndrome.

Williams syndrome (WS) is a rare neurodevelopmental disorder associated to a hemizygous deletion of 28 genes located on chromosome 7q11.23. WS affected subjects frequently suffer from several endocrine abnormalities including hypothyroidism due to defects in thyroid morphology. To date, several genes involved in thyroid dysgenesis have been identified, nonetheless, none of them is located in the 7q11.23 region. Thus, the hypothyroidism-linked molecular features in WS are not yet known. In this study we focused on one of the WS deleted gene, BAZ1B, demonstrating that its downregulation in thyroid cells leads to cell viability and survival decrement. Taking together, our results show that BAZ1B could be the mainly responsible for thyroid defects observed in some of WS patients and that these alterations are activated by PTEN-mediated mechanisms.

The HuR CMLD-2 inhibitor exhibits antitumor effects via MAD2 downregulation in thyroid cancer cells.

Hu antigen R (HuR) is indeed one of the most studied RNA-binding protein (RBP) since its fundamental role both in tumorigenesis and cancer progression. For this reason, downregulation in HuR protein levels or inhibition of HuR biological function are, nowadays, attractive goals in cancer research. Here, we examined the antitumor effects of CMLD-2 in four thyroid cancer cell lines (SW1736, 8505 C, BCPAP and K1). Indeed, CMLD-2 competitively binds HuR protein disrupting its interaction with RNA-targets. 35 µM CLMD-2 produced a significant downregulation in thyroid cancer cell viability, coupled to an increase in apoptosis. Moreover, CMLD-2 treatment hindered both migration and colony formation ability. MAD2 is a microtubules-associated protein known to be greatly overexpressed in cancer and correlating with tumor aggressiveness. Furthermore, MAD2 is known to be a HuR target. CMLD-2 treatment induced a strong MAD2 downregulation and rescue experiments depicted it as a key effector in HuR-mediated in cancer. Altogether, these data contributed to foster HuR inhibition as valid antineoplastic treatment in thyroid cancer, highlighting MAD2 as a novel therapeutic target.

Biological and molecular effects of bromodomain and extra-terminal (BET) inhibitors JQ1, IBET-151, and IBET-762 in OSCC cells.

BACKGROUND: Despite improvements in oral squamous cell carcinoma (OSCC) management, survival rates remain relatively low and novel anti-neoplastic agents are needed. Bromodomain and extra-terminal (BET) inhibitors proved to be promising agents for cancer treatment. We investigated the effects of three BET inhibitors (JQ1, IBET-151, IBET-762) on SCC-25 cell line and primary oral cancer cell culture. METHODS: Cell viability was evaluated by MTT. Protein levels of MCM5 and cleaved-PARP were estimated by Western blot. Clonogenic and migratory abilities were determined by colony forming and scratch assays. BET inhibitors effects on mRNA levels of E-Cadherin, Vimentin, SNAI1, SNAI2, CLU, SERPINI1, MCM5, c-Myc, E2F, IL7R, and PPARg were analyzed by qPCR. RESULTS: BET inhibitors significantly reduced oral cancer cell viability. JQ1 showed the greatest effect reducing cell viability to 10%, both in SCC-25 and primary OSCC cultures (P < 0.001), compared to control cells. Cells treated with BET inhibitors displayed a reduction to 50% in colony forming capacity compared to control cells (P < 0.0001) and the colonies were smaller; they also had a 50%-60% reduction in migratory capacity (P < 0.05) compared to untreated cells. BET inhibitors had a significant impact on genes related to epithelial to mesenchymal transition and other cancer cell markers, notably on MCM5, a gene related to cell cycle control. CONCLUSIONS: BET inhibitors induce both OSCC cell death and reduction of tumor aggressiveness. Molecular mechanisms of BET inhibition involve among others, MCM5 downregulation. Importantly, this study demonstrates for the first time the anti-tumoral effect of IBET-151 and IBET-762 in oral cancer.

Human telomerase reverse transcriptase in papillary thyroid cancer: gene expression, effects of silencing and regulation by BET inhibitors in thyroid cancer cells.

PURPOSE: Mutations in TERT promoter have been detected in the more aggressive papillary thyroid cancers (PTCs). To elucidate the role of TERT as an eligible molecular target in these tumors, the expression of hTERT was analyzed in a series of PTCs and the effects of both pharmacological and RNA-interference-induced hTERT silencing were investigated in two human PTC cell lines (K1 and BCPAP). METHODS: The expression levels of hTERT mRNA and protein were evaluated by real-time PCR and western blot assays, respectively. Effects of hTERT silencing on PTC cell lines were analyzed by MTT, migration and western blot assays. Pharmacological inhibition of hTERT was performed using two bromodomain and extra-terminal (BET) inhibitors, JQ1 and I-BET762. RESULTS: hTERT expression results increased in 20 out of 48 PTCs, including tumors either positive or negative for the presence of hTERT promoter and/or BRAF mutations. In K1 and BCPAP cells, hTERT silencing determined a reduction in cell viability (~50% for K1 and ~70%, for BCPAP, vs control) and migration properties that were associated with a decrease of AKT phosphorylation and ß-Catenin expression. Moreover, hTERT mRNA levels were down-regulated by two BET inhibitors, JQ1 and I-BET762, which at the same dosage (0.5 and 5 µM) reduced the growth of these thyroid cancer cells. CONCLUSIONS: These findings demonstrate that hTERT may represent an excellent therapeutic target in subgroups of aggressive PTCs.

Successful and safe long-term treatment of cerebral aspergillosis with high-dose voriconazole guided by therapeutic drug monitoring.

We report the case of a patient who had cerebral aspergillosis after otorhinolaryngologic surgery and who was successfully and safely treated with high-dose voriconazole (200 mg q6h) for more than 1 year thanks to a TDM-guided approach coupled with pharmacological review and with genotyping of CYP2C19 polymorphisms. The findings support the idea that personalized medicine based on TDM coupled with the need of avoiding drug-drug interactions may be helpful for maximizing the net benefit (probability of efficacy vs. probability of adverse events) of voriconazole in the management of long-term treatment of cerebral aspergillosis.

Genomic Deletion Involving the IMMP2L Gene in Two Cases of Autism Spectrum Disorder.

Mutations/deletions of the IMMP2L gene have been associated with different cognitive/behavioral disturbances, including autism spectrum disorders (ASD). The penetrance of these defects is not complete since they often are inherited from a healthy parent. Using array-CGH in a cohort of 37 ASD patients, we found 2 subjects harboring a deletion inside the IMMP2L gene. In both cases, the IMMP2L gene deletion was inherited: from a healthy mother in one case and from a dyslectic father in the other. In the latter family, the IMMP2L deletion was also detected in the patient's brother, who showed delayed language development. In a cohort of 100 normal controls, no deletions including the IMMP2L gene were observed. However, a recent meta-analysis found no association between IMMP2L deletions and ASD. Our data would indicate that deletions involving the IMMP2L gene may contribute to the development of a subgroup of cognitive/behavioral disorders.

Anti-hTERT siRNA-Loaded Nanoparticles Block the Growth of Anaplastic Thyroid Cancer Xenograft.

The high frequency of hTERT-promoting mutations and the increased expression of hTERT mRNA in anaplastic thyroid cancer (ATC) make TERT a suitable molecular target for the treatment of this lethal neoplasm. In this study, we encapsulated an anti-hTERT oligonucleotide in biocompatible nanoparticles and analyzed the effects of this novel pharmaceutical preparation in preclinical models of ATC. Biocompatible nanoparticles were obtained in an acidified aqueous solution containing chitosan, anti-hTERT oligoRNAs, and poloxamer 188 as a stabilizer. The effects of these anti-hTERT nanoparticles (Na-siTERT) were tested in vitro on ATC cell lines (CAL-62 and 8505C) and in vivo on xenograft tumors obtained by flank injection of CAL-62 cells into SCID mice. The Na-siTERT reduced the viability and migration of CAL-62 and 8505C cells after 48-hour incubation. Intravenous administration (every 48 hours for 13 days) of this encapsulated drug in mice hosting a xenograft thyroid cancer determined a great reduction in the growth of the neoplasm (about 50% vs. untreated animals or mice receiving empty nanoparticles), and decreased levels of Ki67 associated with lower hTERT expression. Moreover, the treatment resulted in minimal invasion of nearby tissues and reduced the vascularity of the xenograft tumor. No signs of toxicity appeared following this treatment. Telomere length was not modified by the Na-siTERT, indicating that the inhibitory effects of neoplasm growth were independent from the enzymatic telomerase function. These findings demonstrate the potential suitability of this anti-TERT nanoparticle formulation as a novel tool for ATC treatment. Mol Cancer Ther; 17(6); 1187-95. ©2018 AACR.