The Pathogenetic Role of the HGF/c-Met System in Papillary Carcinoma of the Thyroid

Molecular Basis and Natural History of Medullary Thyroid Cancer: It is (Almost) All in the RET

Medullary thyroid cancer (MTC) is a rare disease, which can be either sporadic (roughly 75% of cases) or genetically determined (multiple endocrine neoplasia type 2, due to REarranged during Transfection RET germline mutations, 25% of cases). Interestingly, RET pathogenic variants (mainly M918T) have also been reported in aggressive forms of sporadic MTC, suggesting the importance of RET signalling pathways in the pathogenesis of MTC. The initial theory of RET codon-related MTC aggressiveness has been recently questioned by studies suggesting that this would only define the age at disease onset rather than the aggressiveness of MTC. Other factors might however impact the natural history of the disease, such as RET polymorphisms, epigenetic factors, environmental factors, MET (mesenchymal-epithelial transition) alterations, or even other genetic alterations such as RAS family (HRAS, KRAS, NRAS) genetic alterations. This review will detail the molecular bases of MTC, focusing on RET pathways, and the potential mechanisms that explain the phenotypic intra- and interfamilial heterogeneity.

High COX-2 immunostaining in papillary thyroid carcinoma is associated with adverse survival outcomes

BACKGROUND

Thyroid carcinoma is one of the most common malignancies worldwide. More than 70%-80% are papillary thyroid carcinoma (PTC). Many factors influence the PTC pathway of development such as genetic mutations, growth factors, and radiation. More biological understanding of the genetic and molecular pathways is needed in PTC to determine tumor behavior, and initial clinical assessment.

OBJECTIVES

Investigate the relation of COX-2 immunostaining in thyroid carcinoma with clinicopathological parameters to assess whether immunostaining results have prognostic significance.

DESIGN

Retrospective study SETTING: Pathology department, tertiary care center METHODS: Records of PTC were retrieved and tissue microarrays were constructed. Tissue sections were stained using anti-human COX-2 monoclonal antibody. Immunostaining results were recorded and analysed.

MAIN OUTCOME MEASURES

Relationship of COX-2 immunostaining in thyroid carcinoma with clinicopathological parameters.

SAMPLE SIZE

139 tissue samples from 139 patients RESULTS: High versus low COX-2 immunostaining showed no significant differences for most clinicopathological parameters. However, high COX-2 immunostaining showed borderline association with tumor multifocality (P=.05), lower overall (log-rank=8.739 and P=.003), and disease-free survival (log-rank=7.033, P=.008).

CONCLUSION

The study showed a positive association of high COX-2 immunostaining with lower survival outcomes in PTC. COX-2 immunostaining could be a potential prognostic factor for survival in PTC. Additional molecular and clinical investigations are needed for further understanding the molecular pathways of COX-2 in PTC and the feasibility of using inhibitors of COX-2 as adjuvant therapy along with current chemotherapy.

LIMITATIONS

Relatively low number of PTC variants, and no testing of other thyroid carcinomas.

CONFLICT OF INTEREST

None.

DIO3OS as a potential biomarker of papillary thyroid cancer

BACKGROUND

Papillary thyroid carcinoma (PTC) is one of the common clinical tumors, where LncRNA plays an important role in tumorigenesis and its development. The purpose of this study was to explore the role of DIO3OS in PTC.

METHOD

Firstly, this study verified the expression of DIO3OS in PTC through the public database. Then, the differences in DIO3OS expression between the PTC group and paracancerous tissues were verified using the qRT-PCR. A series of in vitro experiments were conducted to verify the function of DIO3OS in PTC, while its involvement in possible pathways was analyzed by the GSEA. The ssGSEA algorithm estimated the immune status using the queue transcriptome graph derived from the TCGA database. Further, the correlation analysis was used to confirm the relationship between DIO3OS and the immune genes.

RESULT

The results showed that the expression of DIO3OS was low in PTC. The same results were also confirmed by qRT-PCR analysis (P= 0.0077). In vitro, DIO3OS was localized within the cytoplasm and exosomes. Overexpression of DIO3OS hindered the proliferation, invasion, and migration of PTC cells. According to the degree of immune cell infiltration, the tumor group was divided into high immune cell infiltration group, medium immune cell infiltration group, and low immune cell infiltration group. The results showed that the DIO3OS was highly expressed in the high immune cell infiltration group (P < 0.001), which was positively correlated with the immune cell infiltration and also correlated with multiple immune genes.

CONCLUSION

In summary, this study illustrated the expression pattern of DIO3OS in PTC, which may be involved in the immune-inflammatory pathway. Hence, our results may provide new diagnostic biomarkers and therapeutic targets for PTC.

Cabozantinib for radioiodine-refractory differentiated thyroid cancer (COSMIC-311): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Patients with radioiodine-refractory differentiated thyroid cancer (DTC) previously treated with vascular endothelial growth factor receptor (VEGFR)-targeted therapy have aggressive disease and no available standard of care. The aim of this study was to evaluate the tyrosine kinase inhibitor cabozantinib in this patient population.

METHODS

In this global, randomised, double-blind, placebo-controlled, phase 3 trial, patients aged 16 years and older with radioiodine-refractory DTC (papillary or follicular and their variants) and an Eastern Cooperative Oncology Group performance status of 0 or 1 were randomly assigned (2:1) to oral cabozantinib (60 mg once daily) or matching placebo, stratified by previous lenvatinib treatment and age. The randomisation scheme used stratified permuted blocks of block size six and an interactive voice-web response system; both patients and investigators were masked to study treatment. Patients must have received previous lenvatinib or sorafenib and progressed during or after treatment with up to two VEGFR tyrosine kinase inhibitors. Patients receiving placebo could cross over to open-label cabozantinib on disease progression confirmed by blinded independent radiology committee (BIRC). The primary endpoints were objective response rate (confirmed response per Response Evaluation Criteria in Solid Tumours [RECIST] version 1.1) in the first 100 randomly assigned patients (objective response rate intention-to-treat [OITT] population) and progression-free survival (time to earlier of disease progression per RECIST version 1.1 or death) in all patients (intention-to-treat [ITT] population), both assessed by BIRC. This report presents the primary objective response rate analysis and a concurrent preplanned interim progression-free survival analysis. The study is registered with ClinicalTrials.gov, NCT03690388, and is no longer enrolling patients.

FINDINGS

Between Feb 27, 2019, and Aug 18, 2020, 227 patients were assessed for eligibility, of whom 187 were enrolled from 164 clinics in 25 countries and randomly assigned to cabozantinib (n=125) or placebo (n=62). At data cutoff (Aug 19, 2020) for the primary objective response rate and interim progression-free survival analyses, median follow-up was 6·2 months (IQR 3·4-9·2) for the ITT population and 8·9 months (7·1-10·5) for the OITT population. An objective response in the OITT population was achieved in ten (15%; 99% CI 5·8-29·3) of 67 patients in the cabozantinib group versus 0 (0%; 0-14·8) of 33 in the placebo (p=0·028) but did not meet the prespecified significance level (α=0·01). At interim analysis, the primary endpoint of progression-free survival was met in the ITT population; cabozantinib showed significant improvement in progression-free survival over placebo: median not reached (96% CI 5·7-not estimable [NE]) versus 1·9 months (1·8-3·6); hazard ratio 0·22 (96% CI 0·13-0·36; p<0·0001). Grade 3 or 4 adverse events occurred in 71 (57%) of 125 patients receiving cabozantinib and 16 (26%) of 62 receiving placebo, the most frequent of which were palmar-plantar erythrodysaesthesia (13 [10%] vs 0), hypertension (11 [9%] vs 2 [3%]), and fatigue (ten [8%] vs 0). Serious treatment-related adverse events occurred in 20 (16%) of 125 patients in the cabozantinib group and one (2%) of 62 in the placebo group. There were no treatment-related deaths.

INTERPRETATION

Our results show that cabozantinib significantly prolongs progression-free survival and might provide a new treatment option for patients with radioiodine-refractory DTC who have no available standard of care.

FUNDING

Exelixis.

Structure-activity relationship study of novel quinazoline-based 1,6-naphthyridinones as MET inhibitors with potent antitumor efficacy

As a privileged scaffold, the quinazoline ring is widely used in the development of EGFR inhibitors, while few quinazoline-based MET inhibitors are reported. In our ongoing efforts to develop new MET-targeted anticancer drug candidates, a series of quinazoline-based 1,6-naphthyridinone derivatives were designed, synthesized, and evaluated for their biological activities. The preliminary SARs studies indicate that the quinazoline scaffold was also acceptable for the block A of class II MET inhibitors. The further pharmacokinetic studies led to the identification of the most promising compound 22a with favorable in vitro potency (MET, IC₅₀ = 9.0 nM), human microsomal metabolic stability (t_1/2 = 621.2 min) and oral bioavailability (F = 42%). Moreover, 22a displayed good in vivo antitumor efficacy (IR of 81% in 75 mg/kg) in MET-positive human glioblastoma U-87 MG xenograft model. These positive results indicated that 22a is a potential new MET-targeted antitumor drug lead, which is worthy of further development.

Thyroid Cancer and Circadian Clock Disruption

Simple Summary

In this manuscript we review the recent literature supporting a biological link between circadian clock disruption and thyroid cancer development and progression. After a brief description of the involvement of the circadian clock machinery in the cell cycle, stemness and cancer, we discuss the scientific evidence supporting the contribution of circadian clockwork dysfunction in thyroid tumorigenesis and the possible molecular mechanisms underlying this relationship. We also point out the potential clinical implications of this link highlighting its impact on thyroid cancer prevention, diagnosis and therapy.

Abstract

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.

Lenvatinib for thyroid cancer treatment: discovery, pre-clinical development and clinical application

Introduction: About one third of patients affected with thyroid cancer present with recurrent disease. Unresectability, advanced disease and radioiodine refractoriness are considered poor prognostic factors. Treatment with small molecules inhibiting molecular signaling can be considered for patients with progressive disease, when other therapeutic strategies cannot be applied. Lenvatinib is a tyrosine kinase inhibitor targeting multiple molecular factors involved in angiogenesis and tumor progression. Preclinical studies have demonstrated the utility of lenvatinib as a targeted therapy for different tumors, including both differentiated and anaplastic thyroid cancer.Areas covered: The authors provide an overview of the preclinical development of lenvatinib in the treatment of thyroid cancer and review its clinical application. They also provide their expert opinion on its development.Expert opinion: Preclinical studies have helped in the understanding of the mechanisms of thyroid carcinogenesis and in the development of a targeted therapy. These findings have represented the rationale for the use of lenvatinib in clinical trials, which have confirmed its utility but yet failed to prove a clear benefit in overall survival. The decision to start a systemic treatment with lenvatinib must be personalized for each patient evaluating the risk/benefits ratio. Treatment emergent adverse events must be considered and reasonably managed by a multidisciplinary approach.

Synthesis of novel 6,7-dimethoxy-4-anilinoquinolines as potent c-Met inhibitors

HGF/c-Met signalling pathway plays an important role in the development of cancers. A series of 6,7-dimethoxy-4-anilinoquinolines possessing benzimidazole moiety were synthesised and identified as potent inhibitors of the tyrosine kinase c-Met. Their in vitro biological activities against three cancer cell lines (A549, MCF-7, and MKN-45) were also evaluated. Most of these compounds exhibited moderate to remarkable potency. Among them, compound 12n showed the most potent inhibitory activity against c-Met with IC₅₀ value of 0.030 ± 0.008 µM and it also showed excellent anticancer activity against the tested cancer cell lines at low micromolar concentration. Molecular docking verified the results and revealed the possible binding mode of the most promising compound 12n into the ATP-binding site of c-Met kinase.

The Emerging Role of Insulin Receptor Isoforms in Thyroid Cancer: Clinical Implications and New Perspectives

Thyroid cancer (TC) is the most common endocrine tumor. Although the majority of TCs show good prognoses, a minor proportion are aggressive and refractory to conventional therapies. So far, the molecular mechanisms underlying TC pathogenesis are incompletely understood. Evidence suggests that TC cells and their precursors are responsive to insulin and insulin-like growth factors (IGFs), and often overexpress receptors for insulin (IR) and IGF-1 (IGF-1R). IR exists in two isoforms, namely IR-A and IR-B. The first binds insulin and IGF-2, unlike IR-B, which only binds insulin. IR-A is preferentially expressed in prenatal life and contributes to development through IGF-2 action. Aggressive TC overexpresses IR-A, IGF-2, and IGF-1R. The over-activation of IR-A/IGF-2 loop in TC is associated with stem-like features and refractoriness to some targeted therapies. Importantly, both IR isoforms crosstalk with IGF-1R, giving rise to the formation of hybrids receptors (HR-A or HR-B). Other interactions have been demonstrated with other molecules such as the non-integrin collagen receptor, discoidin domain receptor 1 (DDR1), and the receptor for the hepatocyte growth factor (HGF), Met. These functional networks provide mechanisms for IR signaling diversification, which may also exert a role in TC stem cell biology, thereby contributing to TC initiation and progression. This review focuses on the molecular mechanisms by which deregulated IR isoforms and their crosstalk with other molecules and signaling pathways in TC cells and their precursors may contribute to thyroid carcinogenesis, progression, and resistance to conventional treatments. We also highlight how targeting these alterations starting from TC progenitors cells may represent new therapeutic strategies to improve the clinical management of advanced TCs.

The MET Inhibitor AZD6094 (Savolitinib, HMPL-504) Induces Regression in Papillary Renal Cell Carcinoma Patient-Derived Xenograft Models

PURPOSE

Papillary renal cell carcinoma (PRCC) is the second most common cancer of the kidney and carries a poor prognosis for patients with nonlocalized disease. The HGF receptor MET plays a central role in PRCC and aberrations, either through mutation, copy number gain, or trisomy of chromosome 7 occurring in the majority of cases. The development of effective therapies in PRCC has been hampered in part by a lack of available preclinical models. We determined the pharmacodynamic and antitumor response of the selective MET inhibitor AZD6094 in two PRCC patient-derived xenograft (PDX) models.

EXPERIMENTAL DESIGN

Two PRCC PDX models were identified and MET mutation status and copy number determined. Pharmacodynamic and antitumor activity of AZD6094 was tested using a dose response up to 25 mg/kg daily, representing clinically achievable exposures, and compared with the activity of the RCC standard-of-care sunitinib (in RCC43b) or the multikinase inhibitor crizotinib (in RCC47).

RESULTS

AZD6094 treatment resulted in tumor regressions, whereas sunitinib or crizotinib resulted in unsustained growth inhibition. Pharmacodynamic analysis of tumors revealed that AZD6094 could robustly suppress pMET and the duration of target inhibition was dose related. AZD6094 inhibited multiple signaling nodes, including MAPK, PI3K, and EGFR. Finally, at doses that induced tumor regression, AZD6094 resulted in a dose- and time-dependent induction of cleaved PARP, a marker of cell death.

CONCLUSIONS

Data presented provide the first report testing therapeutics in preclinical in vivo models of PRCC and support the clinical development of AZD6094 in this indication.