New molecular targeted therapies in thyroid cancer

The Synergistic Effect of Proanthocyanidin and HDAC Inhibitor Inhibit Breast Cancer Cell Growth and Promote Apoptosis

Histone deacetylase inhibitor (HDACi) is a drug mainly used to treat hematological tumors and breast cancer, but its inhibitory effect on breast cancer falls short of expectations. Grape seed proanthocyanidin extract (GSPE) with abundant proanthocyanidins (PAs) has been explored for its inhibition of HDAC activity in vitro and in vivo. To enhance HDACi's effectiveness, we investigated the potential of PA to synergistically enhance HDACi chidamide (Chi), and determined the underlying mechanism. We evaluated the half-inhibitory concentration (IC50) of PA and Chi using the cell counting kit 8 (CCK8), and analyzed drugs' synergistic effect with fixed-ratio combination using the software Compusyn. Breast cancer cell's phenotypes, including short-term and long-term proliferation, migration, invasion, apoptosis, and reactive oxygen species (ROS) levels, were assessed via CCK8, clone-formation assay, wound-healing test, Transwell Matrigel invasion assay, and flow-cytometry. Protein-protein interaction analysis (PPI) and KEGG pathway analysis were used to determine the underlying mechanism of synergy. PA + Chi synergistically inhibited cell growth in T47D and MDA-MB-231 breast cancer cell lines. Short-term and long-term proliferation were significantly inhibited, while cell apoptosis was promoted. Ten signaling pathways were identified to account for the synergistic effect after RNA sequencing. Their synergism may be closely related to the steroid biosynthesis and extracellular matrix (ECM) receptor interaction pathways. PA + Chi can synergistically inhibit breast cancer cell growth and proliferation, and promote apoptosis. These effects may be related to steroid biosynthesis or the ECM receptor pathway.

Development of an athyroid mouse model using 131I ablation after preparation with a low-iodine diet

We optimized the protocol for thyroid ablation in living mice using radioactive iodine (RAI) and a low-iodine diet (LID). To examine the effect of LID on thyroid ablation, mice were randomly divided into 4 groups: Vehicle, ¹³¹I 2.775 MBq, ¹³¹I 5.55 MBq, and LID + ¹³¹I 2.775 MBq. The LID group was fed a LID for up to 7 days and then mice in the ¹³¹I 2.775, ¹³¹I 5.55, and LID + ¹³¹I 2.775 MBq groups were intravenously administrated with ¹³¹I, respectively. Scintigraphy imaging with ^99mTc pertechnetate was performed once in 2 weeks for 4 weeks. After establishment of athyroid mice, control or athyroid mice were injected with human anaplastic thyroid cancer cells co-expressing sodium iodine symporter and enhanced firefly luciferase (ARO/NF) to evaluate RAI uptake. Scintigraphy imaging with ^99mTc pertechnetate was performed with ARO/NF tumor-bearing mice. Scintigraphy imaging showed decreased thyroid uptake in the LID + ¹³¹I 2.775 MBq group compared to other groups. Scintigraphy images showed that tumor uptake was statically higher in athyroid mice than in control mice. These data suggest that these optimized conditions for thyroid ablation could be helpful to establish an in vivo mouse model.

Changes and prognostic value of serum vascular endothelial growth factor in patients with differentiated thyroid cancer

OBJECTIVE

To evaluate the changes and the prognostic value of serum vascular endothelial growth factor (VEGF) in patients with differentiated thyroid cancer (DTC).

SUBJECTS AND METHODS

A total of 79 patients with DTC and 30 healthy individuals were divided into four groups: (1) a healthy control group (n = 30); (2) DTC without recurrence (n = 35; 23 papillary, 12 follicular); (3) DTC with local recurrence (n = 24; 15 papillary, 9 follicular), and (4) DTC with lung metastasis (n = 20; 13 papillary, 7 follicular). Serum VEGF and thyroglobulin levels were measured in all patients.

RESULTS

Serum levels of VEGF were significantly higher in the lung metastasis group than in the other three groups (p < 0.05). Serum thyroglobulin concentration positively correlated with VEGF expression (r = 0.8678, p < 0.001) in patients with thyroid cancer recurrence. Multivariate Cox regression analysis showed that clinical staging (OR = 1.851, 95% CI 1.04-3.47; p = 0.038), noncompliance with postoperative thyroxin replacement therapy (OR = 1.935, 95% CI 1.03-3.65; p = 0.042) and postoperative levels of thyroglobulin (OR = 1.892, 95% CI 1.01-3.56, p = 0.032) were independent predictors for thyroid cancer recurrence. Every additional 100 ng/l of serum VEGF levels increased the risk of thyroid cancer recurrence by 20.3%; but this did not reach statistical significance (OR = 1.203, 95% CI 0.95-1.52; p = 0.125).

CONCLUSIONS

Serum VEGF increased in patients with recurrent thyroid cancer following surgical therapies. The predictive value of serum VEGF requires further investigation.

Insular variant of poorly differentiated thyroid carcinoma

OBJECTIVE

To present a case of an insular variant of poorly differentiated thyroid carcinoma (PDTC) and to review the literature related to diagnosis, natural history, and treatment of this unusual form of thyroid cancer.

METHODS

We present the clinical, laboratory, and pathologic findings of the study patient and review English-language literature related to PDTC published between 1970 and the present.

RESULTS

PDTC is a controversial and rare epithelial thyroid cancer, intermediate between differentiated thyroid carcinoma and anaplastic thyroid carcinoma that exhibits increased aggressiveness, propensity to local recurrence, distant metastases, and increased mortality. PDTC warrants aggressive management with total thyroidectomy followed by radioactive iodine ablation and potentially additional therapy for residual or recurrent disease. Some carcinomas do not take up radioactive iodine, and dedifferentiated clones of distant metastases may evolve. It is unclear whether chemotherapy is beneficial. Use of additional imaging modalities, including positron emission tomography, 18-fludeoxyglucose positron emission tomography/computed tomography, 18-fludeoxyglucose positron emission tomography/computed tomography/magnetic resonance imaging, (124)I positron emission tomography/computed tomography, positron emission tomography/magnetic resonance imaging fusion studies, and recombinant human thyrotropin-stimulated radioactive iodine uptake for cancer surveillance are discussed.

CONCLUSIONS

PDTC is an unusual and aggressive form of thyroid cancer. Fine-needle aspiration cytology may not yield sufficient information to specifically diagnose PDTC. Aggressive management with total thyroidectomy and neck dissection followed by high-dose radioactive iodine remnant ablation is standard. Iodine I 131 whole body scanning is often the initial test for tumor surveillance, with other imaging modalities applied as needed.

Invasive thyroid cancer: management of the trachea and esophagus

Well-differentiated thyroid cancer most commonly presents as an intrathyroidal tumor; however, extrathyroidal extension occurs in approximately 6% to 13% of patients and carries a significant negative impact on survival. Extrathyroidal disease may involve critical structures in the central neck, including the recurrent laryngeal nerves, trachea, esophagus, and larynx, requiring surgery extending significantly beyond the thyroid gland. Appropriate surgical management is of great importance and can normalize survival curves, whereas gross residual disease postoperatively may lead to recurrence and decreased survival. Adjuvant postoperative therapies for thyroid cancers with extrathyroidal extension include thyroid hormone suppression, radioactive iodine therapy, and external beam radiotherapy. This summary reviews approaches to the management of invasive thyroid cancers involving the aerodigestive tract.

Perspectives for improved and more accurate classification of thyroid epithelial tumors

CONTEXT

Histologic examination of thyroid nodules is the current standard to distinguish benign from malignant thyroid epithelial tumors and to classify histologic subtypes. This review analyzes the problems in histological differential diagnosis as well as contradictions between histology and molecular data and describes possibilities to combine histology with molecular data in an effort to more accurately classify thyroid epithelial tumors.

EVIDENCE ACQUISITION

Published literature, addressing the current recommendations for thyroid tumor classification, as well as literature on the application of histology and molecular studies on the etiology of thyroid tumors is analyzed.

EVIDENCE SYNTHESIS

The current histologic criteria to classify thyroid tumors, especially follicular-patterned tumors, are hampered by considerable interobserver variability. The detection of somatic mutations via genotyping and the definition of potentially informative gene expression signatures by microarray analyses, which can distinguish cancer subtypes as well as low- and high-risk cohorts, have recently demonstrated significant diagnostic potential. Moreover, in a routine diagnostic setting, micro-RNA profiling appears most promising due to their relative stability and the high accuracy of their expression profiles.

CONCLUSIONS

It is very likely that molecular definitions of thyroid tumors mentioned in the current World Health Organization classification will be further developed, leading to future progress in defining thyroid tumor types by an integrated histologic and molecular approach. These integrated classifications need to be evaluated for their specific impact on thyroid tumor diagnosis and prognosis.

Incidentally simultaneous occurrence of RET/PTC, H4-PTEN and BRAF mutation in papillary thyroid carcinoma

Because interaction existed between PTEN and RET-RAS-RAF-MAPK pathway, H4-PTEN (a newly identified gene rearrangement), RET/PTC and BRAF mutation were scanned in 125 Chinese patients with papillary thyroid carcinoma (PTC). H4-PTEN were detected in 9.6% of PTC and the frequency of the occurrence of BRAF mutation and/or RET/PTC in H4-PTEN positive tumors was extremely high (75%). On the other hand, age has an important effect on the aberration formation and young age renders more prone to multi-genetic events. A combinational scanning of these involved changes will improve the predictive value of molecular aberrations in the treatment of PTC.

The discovery of substituted 4-(3-hydroxyanilino)-quinolines as potent RET kinase inhibitors

Substituted 4-(3-hydroxyanilino)-quinoline compounds, initially identified as small-molecule inhibitors of src family kinases, have been evaluated as potential inhibitors of RET kinase. Three compounds, 38, 31, and 40, had K(i)'s of 3, 25, and 50 nM in an in vitro kinase assay; while a cell based kinase assay showed K(i)'s of 300, 100, and 45 nM, respectively. These compounds represent potential new leads for the treatment of medullary and papillary thyroid cancer.

Failure to recognize multiple endocrine neoplasia 2B: more common than we think?

BACKGROUND

Multiple endocrine neoplasia 2B (MEN2B) has a classic childhood phenotypic presentation characterized by mucosal neuromas and marfanoid habitus. However, the diagnosis of MEN2B is often delayed beyond childhood, at which time medullary thyroid carcinoma (MTC) may be regionally advanced or metastatic. We examined the extent of this delay and its impact on the treatment of MTC.

METHODS

Patients in the MEN database were retrospectively analyzed to determine the age at first presentation for a MEN2B-related complaint and the subsequent time to correct diagnosis. Operative and pathology reports were reviewed to determine the extent of thyroidectomy and cervical lymphadenectomy during the initial and subsequent neck operations.

RESULTS

We identified 22 patients with MEN2B, 20 were de novo cases and a M918T RET gene mutation was confirmed in 18 of the 22 patients. Median age at diagnosis of MTC was 13 years (range 6-25 years). The median delay in diagnosis was 26 months (range 0-18 years). Persistent local-regional MTC was present following the initial cervical operation in 12 of 22 patients (55%); including 4 of 13 with MEN2B diagnosed prior to initial surgery and 8 of 9 with MEN2B diagnosed after initial surgery.

CONCLUSIONS

Most patients displayed phenotypic characteristics of MEN2B long before the correct diagnosis was made. Half of the patients failed to undergo complete resection of MTC at their initial thyroid surgery. Early recognition of the MEN2B phenotype with a thoughtful approach to preoperative staging and surgery will maximize control of MTC and minimize the need for reoperation.