Recent advances in molecular diagnosis of thyroid cancer

Preclinical Pharmacokinetics in Tumors and Normal Tissues of the Antigene PNA Oligonucleotide MYCN-Inhibitor BGA002

Although MYCN has been considered an undruggable target, MYCN alterations confer poor prognosis in many pediatric and adult cancers. The novel MYCN-specific inhibitor BGA002 is an antigene peptide nucleic acid oligonucleotide covalently bound to a nuclear localization signal peptide. In the present study, we characterized the pharmacokinetics (PK) of BGA002 after single and repeated administration to mice using a novel specific enzyme-linked immunosorbent assay. BGA002 concentrations in plasma showed linear PK, with dose proportional increase across the tested dose levels and similar exposure between male and female and between intravenous and subcutaneous route of administration. Repeated dosing resulted in no accumulation in plasma. Biodistribution up to 7 days after single subcutaneous administration of [14C]-radiolabeled BGA002 showed broad tissues and organ distribution (suggesting a potential capability to reach primary tumor and metastasis in several body sites), with high concentrations in kidney, liver, spleen, lymph nodes, adrenals, and bone marrow. Remarkably, we demonstrated that BGA002 concentrates in tumors after repeated systemic administrations in three mouse models with MYCN amplification (neuroblastoma, rhabdomyosarcoma, and small-cell lung cancer), leading to a significant reduction in tumor weight. Taking into account the available safety profile of BGA002, these data support further evaluation of BGA002 in patients with MYCN-positive tumors.

Circ_PSD3 promotes the progression of papillary thyroid carcinoma via the miR-637/HEMGN axis

AIMS

In the present study, we aimed to uncover the potential functions of circular RNA (circRNA) pleckstrin and Sec7 domain containing 3 (circ_PSD3) in papillary thyroid carcinoma (PTC) development.

MAIN METHODS

The abundance of circ_PSD3, PSD3 messenger RNA (mRNA), microRNA-637 (miR-637) and hemogen (HEMGN; EDAG-1) mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was employed to measure cell cycle progression and cell apoptosis. Western blot assay was used to examine protein expression. The proliferation ability and motility of PTC cells were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assays, respectively. The interaction between miR-637 and circ_PSD3 or HEMGN was tested by dual-luciferase reporter assay. Animal experiments were used to explore the role of circ_PSD3 in PTC progression in vivo.

KEY FINDINGS

Circ_PSD3 was aberrantly up-regulated in PTC tumor tissues compared with adjacent normal tissues. Circ_PSD3 and HEMGN promoted the cell cycle progression, proliferation and metastasis and impeded the apoptosis of PTC cells. MiR-637 was a direct target of circ_PSD3, and miR-637 directly interacted with HEMGN mRNA in PTC cells. Circ_PSD3 silencing-induced effects in PTC cells were partly attenuated by the addition of anti-miR-637 or HEMGN overexpression plasmid. Circ_PSD3/miR-637/HEMGN regulated the activity of PI3K/Akt signal pathway in PTC cells. Circ_PSD3 silencing inhibited the tumor growth in vivo.

SIGNIFICANCE

Circ_PSD3 promoted the progression of PTC through regulating miR-637/HEMGN axis and activating PI3K/Akt signaling. Circ_PSD3/miR-637/HEMGN signaling axis might be a potential target for PTC therapy.

Liquid Biopsy as a Minimally Invasive Source of Thyroid Cancer Genetic and Epigenetic Alterations

In the blood of cancer patients, some nucleic acid fragments and tumor cells can be found that make it possible to trace tumor changes through a simple blood test called “liquid biopsy”. The main components of liquid biopsy are fragments of DNA and RNA shed by tumors into the bloodstream and circulate freely (ctDNAs and ctRNAs). Tumor cells which are shed into the blood (circulating tumor cells or CTCs), and exosomes that have been investigated for non-invasive detection and monitoring several tumors including thyroid cancer. Genetic and epigenetic alterations of a thyroid tumor can be a driver for tumor genesis or essential for tumor progression and invasion. Liquid biopsy can be real-time representative of such genetic and epigenetic alterations to trace tumors. In thyroid tumors, the circulating BRAF mutation is now taken into account for both thyroid cancer diagnosis and determination of the most effective treatment strategy. Several recent studies have indicated the ctDNA methylation pattern of some iodine transporters and DNA methyltransferase as a diagnostic and prognostic biomarker in thyroid cancer as well. There has been a big hope that the recent advances of genome sequencing together with liquid biopsy can be a game changer in oncology.

The efficacy of HRAS and CDK4/6 inhibitors in anaplastic thyroid cancer cell lines

PURPOSE

Anaplastic thyroid carcinomas (ATCs) are non-responsive to multimodal therapy, representing one of the major challenges in thyroid cancer. Previously, our group has shown that genes involved in cell cycle are deregulated in ATCs, and the most common mutations in these tumours occurred in cell proliferation and cell cycle related genes, namely TP53, RAS, CDKN2A and CDKN2B, making these genes potential targets for ATCs treatment. Here, we investigated the inhibition of HRAS by tipifarnib (TIP) and cyclin D-cyclin-dependent kinase 4/6 (CDK4/6) by palbociclib (PD), in ATC cells.

METHODS

ATC cell lines, mutated or wild type for HRAS, CDKN2A and CDKN2B genes, were used and the cytotoxic effects of PD and TIP in each cell line were evaluated. Half maximal inhibitory concentration (IC50) values were determined for these drugs and its effects on cell cycle, cell death and cell proliferation were subsequently analysed.

RESULTS

Cell culture studies demonstrated that 0.1 µM TIP induced cell cycle arrest in the G2/M phase (50%, p < 0.01), cell death, and inhibition of cell viability (p < 0.001), only in the HRAS mutated cell line. PD lowest concentration (0.1 µM) increased significantly cell cycle arrest in the G0/G1 phase (80%, p < 0.05), but only in ATC cell lines with alterations in CDKN2A/CDKN2B genes; additionally, 0.5 µM PD induced cell death. The inhibition of cell viability by PD was more pronounced in cells with alterations in CDKN2A/CDKN2B genes (p < 0.05) and/or cyclin D1 overexpression.

CONCLUSIONS

This study suggests that TIP and PD, which are currently in clinical trials for other types of cancer, may play a relevant role in ATC treatment, depending on the specific tumour molecular profile.

Suppression of CCT3 inhibits malignant proliferation of human papillary thyroid carcinoma cell

Papillary thyroid carcinoma (PTC) is the most frequently occurring subtype of thyroid cancer. A certain portion of PTCs can progress to recurrent metastatic cancer. Currently, there remains no effective molecular target therapy for PTCs. As a subunit of the chaperonin containing TCP1 (CCT) complex, CCT3 is involved in various biological processes. CCT3 has been reported to drive the proliferation of hepatocellular carcinoma cells. Nevertheless, it remains unknown whether CCT3 regulates the development of PTC. The present study examined CCT3 protein expression in 30 PTC samples from patients undergoing thyroidectomy. A significant increase was observed in CCT3 expression in the PTC samples compared with the matched adjacent normal thyroid tissues. Lentiviral-mediated small interfering RNAs were used to knock down CCT3 in K1 cells. It was observed that the expression of CCT3 was significantly suppressed in K1 cells infected with lentivirus containing a CCT3-targeting short hairpin RNA. Our results showed that CCT3 knockdown markedly decreased the proliferation and cell cycle progression of K1 cells. In addition, the knockdown of CCT3 induced apoptosis of K1 cell. Taken together, the findings of the present study indicated that CCT3 presents as a potential molecular marker of PTC and regulates the development of PTC in humans.

Association of p53 (-16ins-pro) haplotype with the decreased risk of differentiated thyroid carcinoma in Iranian-Azeri patients

Association of P53 polymorphisms with the increased risk of various cancers has been investigated in numerous studies. However, the results were conflicting and no polymorphism has been determined as a definite risk factor. It is likely that the study of P53 combined genotypes and haplotypes may be more useful than individual polymorphisms. Thus, in this study, we analyzed the associations of intron 3 Ins16bp and exon 4 Arg72Pro polymorphisms, as well as their combined genotypes and haplotypes with the risk of differentiated thyroid carcinoma in Iranian-Azeri patients. This case-control study was performed on 84 Iranian Azeri patients with differentiated thyroid carcinoma and 150 healthy subjects. Intron 3 genotype was determined using PCR products analysis on polyacrylamide gels and AS-PCR was used for genotyping Arg72Pro polymorphism. The javastat online statistics package software and SHEsis program were applied for data analysis. There was no significant difference in genotype frequencies of both two polymorphisms between cases and controls. However, the (-16 ins/-16 ins) (Arg/Pro) genotype combination had a noticeable but not significant association with decreased risk of thyroid cancer development (OR = 0.497 95%CI: 0.209-1.168 P = 0.080) and also the frequency of (-16 ins-Pro) haplotype was significantly higher in controls rather than patients (OR = 0.543 95%CI: 0.326-0.903 P = 0.018). In our study, there was association between (-16 ins-Pro) haplotype with decreased risk of differentiated thyroid carcinoma development in Iranian-Azeri patients.

Evaluation of PTEN, PI3K, MTOR, and KRAS expression and their clinical and prognostic relevance to differentiated thyroid carcinoma

Aim of the study

Important signalling pathways play fundamental roles in the pathogenesis of thyroid carcinoma (TC). PTEN, mTOR, PI3K-p85 and K-Ras are the principal factors involved in these signalling pathways. To immunohistochemically examine the expressions of PI3K, mTOR and PTEN in patients suffering from follicular TC, papillary TC or variants thereof, as well as to investigate KRAS mutations via PCR to determine their clinical and prognostic relevance to differentiated thyroid cancer.

Material and methods

The expression of PTEN, PI3K-p85 and mTOR was immunohistochemically examined, and the mutation of K-Ras was examined via PCR. The results obtained were compared to the clinico-pathologic characteristics of the patients.

Results

A significant correlation was found between p85 expression and lymphovascular invasions and between PTEN expression and multifocality (p = 0.048 and p = 0.04, respectively), and a correlation between p85 and capsular invasion was found, with a borderline statistical significance (p = 0.056). No expression of PTEN, p85 or Mtor was detected in normal tissue. K-Ras mutation was examined in 66 of the 101 patients (57.4%), and the percentage of patients exhibiting a K-Ras mutation was 17.4%. All of the patients exhibiting a K-Ras mutation were women (p = 0.047). The disease-free survival was 44.6 months (95% CI: 37.9–51.3) and was statistically significantly higher in the group that displayed level 1 or lower expression of p85 (p = 0.043).

Conclusions

The expression levels of the aforementioned markers were significantly higher in TC cells than in normal tissue. A significant correlation was detected between K-Ras mutation and gender. This study demonstrates that p85 and PTEN are markers that should be evaluated in further studies of TC.

Candidate agents for papillary thyroid cancer identified by gene expression analysis

A better understanding of the molecular mechanisms involved in papillary thyroid cancer (PTC) is needed to manage these patients effectively. Our objectives were to expand our understanding of this disease, and to identify biologically active small molecules capable to reverse PTC. We downloaded gene expression data of PTC from Gene Expression Omnibus database and employed computational bioinformatics analysis to compare gene expression patterns with normal tissues. Small molecules that induced inverse gene changes to the PTC were identified. A total of 2,154 differentially expressed genes (DEGs) with a false discovery rate of 0.01 were identified. These 2,154 DEGs were significantly enriched in 17 pathways, including pathways associated with signal transduction, tumorigenesis and lipid or amino acid metabolism. In addition, we identified large amount of small molecules that capable to reverse PTC. We found a group of small molecules that can provide new ideas for the therapeutic studies in PTC. These drugs are clearly a direction that warrants additional consideration.

Evaluation of expression and function of vascular endothelial growth factor receptor 2, platelet derived growth factor receptors-alpha and -beta, KIT, and RET in canine apocrine gland anal sac adenocarcinoma and thyroid carcinoma

Background

Toceranib phosphate (Palladia) has a reported objective response rate of 25% in both canine apocrine gland anal sac adenocarcinoma (AGASACA) and thyroid carcinoma (TC), with stable disease occurring in an additional 50-60% of dogs. The basis for the observed responses to toceranib is not known. The purpose of this study was to evaluate AGASACA and TC samples for the expression and activation of VEGFR2, PDGFRα, PDGFRβ, KIT and RET to assess whether dysregulation of these receptor tyrosine kinases (RTKs) may contribute to the biologic activity of toceranib.

Results

mRNA for VEGFR2, PDGFRα/β, KIT and RET was detected in all AGASACA samples. mRNA for VEGFR2, PDGFRα/β, and KIT was detected in all TC samples, while mRNA for RET was amplified in 10/15 samples. No phosphorylation of VEGFR2, PDGFRα/β, or KIT was observed on the arrays. However, phosphorylation of RET was detected in 54% of the primary AGASACA and 20% of TC. VEGFR2 was expressed in 19/24 primary and 6/10 metastatic AGASACA and 6/15 TC samples. KIT was present in 8/24 primary and 3/10 metastatic AGASACA and 9/15 TC samples. PDGFRα expression was noted in all tumor samples. In contrast PDGFRβ expression was found in only a few tumor samples but was evident in the stroma of all tumor specimens.

Conclusions

Known targets of toceranib are expressed in both AGASAC and TC. Given the observed expression of VEGFR and PDGFRα/β and phosphorylation of RET, these RTKs merit investigation as to their roles in the biology of AGSACA and TC and their contribution to toceranib’s activity.