Novel chemotherapy options for advanced thyroid tumors: small molecules offer great hope

Thyroid Carcinoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Differentiated thyroid carcinomas is associated with an excellent prognosis. The treatment of choice for differentiated thyroid carcinoma is surgery, followed by radioactive iodine ablation (iodine-131) in select patients and thyroxine therapy in most patients. Surgery is also the main treatment for medullary thyroid carcinoma, and kinase inhibitors may be appropriate for select patients with recurrent or persistent disease that is not resectable. Anaplastic thyroid carcinoma is almost uniformly lethal, and iodine-131 imaging and radioactive iodine cannot be used. When systemic therapy is indicated, targeted therapy options are preferred. This article describes NCCN recommendations regarding management of medullary thyroid carcinoma and anaplastic thyroid carcinoma, and surgical management of differentiated thyroid carcinoma (papillary, follicular, Hürthle cell carcinoma).

Efficacy and safety of peptide receptor radionuclide therapy in advanced radioiodine-refractory differentiated thyroid cancer and metastatic medullary thyroid cancer: a systematic review

Background

It has been shown that a subgroup of patients with differentiated thyroid cancer (DTC) and medullary thyroid carcinoma (MTC) would progress to advanced stages of thyroid cancer. Therefore, the present study was done to systematically review available evidence in order to investigate efficacy and safety of peptide receptor radionuclide therapy (PRRT) in the patients with advanced radioiodine refractory differentiated thyroid cancer (RR-DTC) and metastatic MTC.

Methods

For this purpose, relevant studies investigated safety and efficacy of PRRT in the patients with advanced RR-DTC and metastatic MTC were identified by searching Medline (Pubmed, Ovid, and Ebsco), Scopus, Embase, Web of Science, and Cochrane Library databases (from database inception to March 24, 2021). The review was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. Searching was done independently by two investigators. Two researchers independently extracted the data and any disagreement was adjudicated by consensus. Quality of the studies was assessed using the tool of case reports/series in systematic reviews.

Results

Among 2284 related papers, 41 papers met the inclusion criteria. A total of 157 patients with RR-DTC were treated with PPRT. Biochemical and objective responses (partial and complete) were observed in 25.3 and 10.5% of patients, respectively. Among 220 patients with metastatic MTC, biochemical and objective responses were observed in 37.2 and 10.6% of the patients, respectively.

Forty-six deaths were reported in 95 patients with advanced RR-DTC. In addition, 63 deaths were observed in 144 patients with metastatic MTC. Major side effects were reported in 124 patients treated with ⁹⁰Y -based agent. In the patients treated with 177Lu-DOTA-TATE and 111In-Octreotide, mild and transient hematologic or renal complications were reported.

Conclusion

Findings of the study revealed that in the absence of the established treatment for the patients with RR-DTC and metastatic MTC, PRRT could be effective with few adverse events.

Trial registration

PROSPERO registration number: CRD42019125245.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08257-x.

Lenvatinib and sorafenib for differentiated thyroid cancer after radioactive iodine: a systematic review and economic evaluation

BACKGROUND

Thyroid cancer is a rare cancer, accounting for only 1% of all malignancies in England and Wales. Differentiated thyroid cancer (DTC) accounts for ≈94% of all thyroid cancers. Patients with DTC often require treatment with radioactive iodine. Treatment for DTC that is refractory to radioactive iodine [radioactive iodine-refractory DTC (RR-DTC)] is often limited to best supportive care (BSC).

OBJECTIVES

We aimed to assess the clinical effectiveness and cost-effectiveness of lenvatinib (Lenvima®; Eisai Ltd, Hertfordshire, UK) and sorafenib (Nexar®; Bayer HealthCare, Leverkusen, Germany) for the treatment of patients with RR-DTC.

DATA SOURCES

EMBASE, MEDLINE, PubMed, The Cochrane Library and EconLit were searched (date range 1999 to 10 January 2017; searched on 10 January 2017). The bibliographies of retrieved citations were also examined.

REVIEW METHODS

We searched for randomised controlled trials (RCTs), systematic reviews, prospective observational studies and economic evaluations of lenvatinib or sorafenib. In the absence of relevant economic evaluations, we constructed a de novo economic model to compare the cost-effectiveness of lenvatinib and sorafenib with that of BSC.

RESULTS

Two RCTs were identified: SELECT (Study of [E7080] LEnvatinib in 131I-refractory differentiated Cancer of the Thyroid) and DECISION (StuDy of sorafEnib in loCally advanced or metastatIc patientS with radioactive Iodine-refractory thyrOid caNcer). Lenvatinib and sorafenib were both reported to improve median progression-free survival (PFS) compared with placebo: 18.3 months (lenvatinib) vs. 3.6 months (placebo) and 10.8 months (sorafenib) vs. 5.8 months (placebo). Patient crossover was high (≥ 75%) in both trials, confounding estimates of overall survival (OS). Using OS data adjusted for crossover, trial authors reported a statistically significant improvement in OS for patients treated with lenvatinib compared with those given placebo (SELECT) but not for patients treated with sorafenib compared with those given placebo (DECISION). Both lenvatinib and sorafenib increased the incidence of adverse events (AEs), and dose reductions were required (for > 60% of patients). The results from nine prospective observational studies and 13 systematic reviews of lenvatinib or sorafenib were broadly comparable to those from the RCTs. Health-related quality-of-life (HRQoL) data were collected only in DECISION. We considered the feasibility of comparing lenvatinib with sorafenib via an indirect comparison but concluded that this would not be appropriate because of differences in trial and participant characteristics, risk profiles of the participants in the placebo arms and because the proportional hazard assumption was violated for five of the six survival outcomes available from the trials. In the base-case economic analysis, using list prices only, the cost-effectiveness comparison of lenvatinib versus BSC yields an incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained of £65,872, and the comparison of sorafenib versus BSC yields an ICER of £85,644 per QALY gained. The deterministic sensitivity analyses show that none of the variations lowered the base-case ICERs to < £50,000 per QALY gained.

LIMITATIONS

We consider that it is not possible to compare the clinical effectiveness or cost-effectiveness of lenvatinib and sorafenib.

CONCLUSIONS

Compared with placebo/BSC, treatment with lenvatinib or sorafenib results in an improvement in PFS, objective tumour response rate and possibly OS, but dose modifications were required to treat AEs. Both treatments exhibit estimated ICERs of > £50,000 per QALY gained. Further research should include examination of the effects of lenvatinib, sorafenib and BSC (including HRQoL) for both symptomatic and asymptomatic patients, and the positioning of treatments in the treatment pathway.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017055516.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Anaplastic Thyroid Carcinoma, Version 2.2015

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Thyroid Carcinoma focuses on anaplastic carcinoma because substantial changes were made to the systemic therapy recommendations for the 2015 update. Dosages and frequency of administration are now provided, docetaxel/doxorubicin regimens were added, and single-agent cisplatin was deleted because it is not recommended for patients with advanced or metastatic anaplastic thyroid cancer.

Nonthermal plasma induces apoptosis in ATC cells: involvement of JNK and p38 MAPK-dependent ROS

PURPOSE

To determine the effects of nonthermal plasma (NTP) induced by helium (He) alone or He plus oxygen (O₂) on the generation of reactive oxygen species (ROS) and cell death in anaplastic thyroid cancer cells.

MATERIALS AND METHODS

NTP was generated in He alone or He plus O₂ blowing through a nozzle by applying a high alternating current voltage to the discharge electrodes. Optical emission spectroscopy was used to identify various excited plasma species. The apoptotic effect of NTP on the anaplastic thyroid cancer cell lines, such as HTH83, U-HTH 7, and SW1763, was verified with annexin V/propidium staining and TUNEL assay. ROS formation after NTP treatment was identified with fluorescence-activated cell sorting with DCFDA staining. The mitogen-activated protein kinase pathways and caspase cascade were investigated to evaluate the molecular mechanism involved and cellular targets of plasma.

RESULTS

NTP induced significant apoptosis in all three cancer cell lines. The plasma using He and O₂ generated more O₂-related species, and increased apoptosis and intracellular ROS formation compared with the plasma using He alone. NTP treatment of SW1763 increased the expression of phosphor-JNK, phosphor-p38, and caspase-3, but not phosphor-ERK. Apoptosis of SW1763 as well as expressions of elevated phosphor-JNK, phosphor-p38, and caspase-3 induced by NTP were effectively inhibited by intracellular ROS scavengers.

CONCLUSION

NTP using He plus O₂ induced significant apoptosis in anaplastic cancer cell lines through intracellular ROS formation. This may represent a new promising treatment modality for this highly lethal disease.

Antineoplastic activity of the multitarget tyrosine kinase inhibitors CLM3 and CLM94 in medullary thyroid cancer in vitro

BACKGROUND

We report the antineoplastic and anti-angiogenic activity of the pyrazolo[3,4-d]pyrimidine derivative CLM3 and the cyclic amide CLM94, both multiple tyrosine kinase inhibitors (TKIs), in human primary medullary thyroid cancer (P-MTC) cells, and in vitro in the medullary thyroid cancer (MTC) cell lines TT (harboring a RET C634W activating mutation) and MZ-CRC-1 (carrying the MEN2B RET mutation Met891Thr).

METHODS

The antiproliferative and proapoptotic effects of CLM3 and CLM94 (1, 5, 10, 30, and 50 μmol/L) were tested in P-MTC cells obtained at operation, and in TT cells. In addition, the antiproliferative effects of CLM3 and CLM94 (0.005, 0.05, 0.5, and 5 μmol/L) were tested in TT and MZ-CRC-1 cells after 7 days of treatment to compare the results with those previously reported in the literature.

RESULTS

CLM3 and CLM94 (30 or 50 μmol/L) inhibited (P < .01) the proliferation of the P-MTC cells, TT cells, and MZ-CRC-1 cells and increased the level of apoptosis in a dose-dependent manner at 10, 30, and 50 μmol/L (P < .001), while having no effect on migration or invasion. The inhibition of proliferation by CLM3 and CLM94 was similar among P-MTC cells with/without RET mutations, and similar effects were observed regarding the increased level of apoptosis. Furthermore, CLM3 and CLM94 significantly decreased vascular endothelial growth factor-A expression in TT cells.

CONCLUSION

The antitumor activities of the multiple TKIs CLM3 and CLM94 were demonstrated in both primary MTC cultures as well as 2 established MTC cell lines in vitro, opening an avenue for future clinical evaluations.

Notable decrease of malignant pleural effusion after treatment with sorafenib in radioiodine-refractory follicular thyroid carcinoma

BACKGROUND

Malignant pleural effusion (MPE) caused by metastatic differentiated thyroid carcinoma (DTC) is usually associated with a rapid fatal outcome and should be recognized as a grim prognostic indicator. A standard therapeutic strategy has not been established for this situation. Here, we report a radioiodine-refractory follicular thyroid carcinoma (FTC) patient in whom a notable decrease of MPE was achieved after treatment with sorafenib.

PATIENT FINDINGS

A 50-year-old patient underwent a total thyroidectomy and resection of recurrence for poorly differentiated FTC followed by radioiodine therapy with a negative whole body scan. One year later, dissection of the inferior lobe of the left lung was performed because two fluorodeoxyglucose-avid nodules were identified; pathological examination revealed a metastatic poorly differentiated FTC. Half a year later, he was referred to our clinic because of cough, thoracic pain, nausea, and loss of appetite. Chest computed tomography showed right lung multiple nodules, left pleural effusion, and left lung collapse with left-sided pleural thickening. We treated him with sorafenib. Clinical and radiographic assessments were performed periodically.

SUMMARY

Symptoms and signs improved dramatically and continuously after initiation of sorafenib treatment. A duration of more than 12 weeks of apparent reduction of pleural effusion was achieved, which was confirmed by consecutive computed tomography examinations. Despite grade 1 alopecia, no other obvious treatment-related adverse events occurred.

CONCLUSIONS

As a grim prognostic indicator for patients with DTC, no standard treatment recommendation for pleural effusion exists. Targeted therapy using sorafenib may be an effective therapeutic strategy in the treatment of MPE caused by FTC.

RECIST 1.1 and serum thyroglobulin measurements in the evaluation of responses to sorafenib in patients with radioactive iodine-refractory differentiated thyroid carcinoma

The present study was designed to investigate the association between response evaluation criteria in solid tumors (RECIST) 1.1 and 1.0, and to explore the utility of thyroglobulin (Tg) measurements in assessing tumor responses to sorafenib in patients with radioactive iodine (RAI)-refractory differentiated thyroid carcinoma (DTC). In total, 23 patients with RAI-refractory DTC were enrolled. A comparison of RECIST 1.1 and 1.0 was performed in all patients with measurable disease. Following the exclusion of patients who were positive for anti-Tg antibody, the correlation between RECIST 1.1 and Tg was investigated in patients with measurable disease, and the concordance of the change in Tg between these patients and the patients with non-measurable disease only was analyzed over time. Tumor responses, assessed by RECIST 1.1 and 1.0, were concordant in 96% of the 23 records. However, the number of target lesions, according to RECIST 1.1, was significantly lower than when using RECIST 1.0. Progressive disease (PD) was identified in one of the five patients who underwent fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) scanning. A correlation between the Tg levels and the sum of the diameters of the target lesions was verified, with the percentage decrease in Tg levels significantly greater than that in the radiograph, demonstrating shrinkage. Furthermore, the percentage change in Tg levels was consistent between the patients with measurable disease and the subjects with non-measurable disease only. In conclusion, in patients with RAI-refractory DTC, RECIST 1.1 is highly concordant with RECIST 1.0 in the assessment of responses to sorafenib treatment, with the advantage of simplified procedures and the complementary use of FDG-PET. Tg measurements, in concordance with RECIST 1.1, are valuable in the evaluation of tumor responses.

Brain metastasis from follicular thyroid carcinoma: treatment with sorafenib

BACKGROUND

Sorafenib has shown promise in the treatment of patients with advanced or metastatic thyroid carcinoma. However, its therapeutic effect has not been assessed in patients with brain metastases from follicular thyroid carcinoma (FTC). Here, we report a patient in whom this treatment was employed with a relatively favorable response.

PATIENT AND METHODS

A 56-year-old woman had a thyroidectomy 8 years previously for FTC. She subsequently developed lung metastases, for which she received seven courses of radioiodine ((131)I) therapy. She developed right hemiplegia and other symptoms and was found to have a ≈ 5-cm lesion in the left parietal lobe. Radiosurgery with a total dose of 28 Gy (7 Gy/day, for 4 days) to treat her brain metastatic lesion was ineffective, and she was referred to us. We treated her with sorafenib, 200 mg orally, on a twice-daily basis. The effect of this intervention was assessed clinically and radiographically using Response Evaluation Criteria in Solid Tumors (RECIST).

SUMMARY

Symptoms and signs improved dramatically and continuously after initiation of sorafenib treatment. Partial response (PR) in the brain metastasis and stable disease (SD) in lung metastatic lesions were verified by consecutive imaging findings for more than one year. Despite alopecia, other treatment-related adverse events did not occur.

CONCLUSIONS

Targeted therapy such as with sorafenib could be an effective alternative therapeutic strategy in the treatment of progressive brain metastasis from differentiated thyroid carcinoma (DTC) when surgery, external beam radiation, and (131)I are not suitable or give poor outcomes. A paradigm of sustained low dose of sorafenib (200 mg,twice a day) may be well-tolerated without compromising maintenance of the therapeutic effect.

Clinical utility of vandetanib in the treatment of patients with advanced medullary thyroid cancer

Vandetanib (ZD6474) became the first systemic agent to be approved for the treatment of metastatic or locally advanced medullary thyroid cancer. It was a proof of principle, because it is an orally bioavailable medication that targets the growth factors felt to be important in the pathogenesis of this disease, ie, the rearranged during transfection proto-oncogene and vascular endothelial growth factor receptor. It was tested initially in two Phase II studies at doses of 100 mg and 300 mg daily. Although activity was seen at both doses, the higher dose was chosen for a randomized, placebo-controlled Phase II study. This trial, which accrued more than 300 patients, showed a statistically significant benefit for the group taking vandetanib compared with those taking placebo medication. Progression-free survival for the vandetanib arm has not been reached, compared with 19 months for the placebo arm. The main toxicity appears to be diarrhea, although some patients experienced significant side effects, including torsades de pointes and sudden cardiac death. Therefore, it is now necessary for practitioners to enroll in a Risk Evaluation Mitigation Strategy before being allowed to prescribe this medication, to reduce the risk of serious side effects occurring.

Synthesis and biological evaluation of phenstatin metabolites

Previous investigations on the incubation of phenstatin with rat and human microsomal fractions revealed the formation of nine main metabolites. The structures of eight of these metabolites have been now confirmed by synthesis and their biological properties have been reported. Eaton's reagent was utilized as a convenient condensing agent, allowing, among others, a simple multigram scale preparation of phenstatin. Synthesized metabolites and related compounds were evaluated for their antiproliferative activity in the NCI-60 cancer cell line panel, and for their effect on microtubule assembly. Metabolite 23 (2'-methoxyphenstatin) exhibited the most potent in vitro cytotoxic activity: inhibition of the growth of K-562, NCI-H322M, NCI-H522, KM12, M14, MDA-MB-435, NCI/ADR-RES, and HS 578T cell lines with GI(50) values <10nM. It also showed more significant tubulin polymerization inhibitory activity than parent phenstatin (3) (IC(50)=3.2 μM vs 15.0 μM) and induced G2/M arrest in murine leukemia DA1-3b cells. The identification of this active metabolite led to the design and synthesis of analogs with potent in vitro cytotoxicity and inhibition of microtubule assembly.

Vandetanib (ZD6474) in the Treatment of Medullary Thyroid Cancer

Vandetanib (ZD6474) is an orally bioavailable small molecule tyrosine kinase inhibitor of multiple growth factor receptors, including RET (Rearrange during transfection), vascular endothelial growth factor receptor-2 (VEGFR-2) and epidermal growth factor receptor (EGFR). The activity against RET and VEGF made it a good choice in the treatment of medullary thyroid cancer (MTC). As there is considerable cross talk between growth factor pathways, dual inhibition with such agents has become an attractive strategy, in the treatment of many malignancies with encouraging Phase II clinical trial data to date. Vandetanib was tested in two Phase II trials in the treatment of patients with medullary thyroid cancer at doses of 100 mg and 300 mg daily respectively. The encouraging results of these 2 trials led to a randomized phase II trial comparing this medication to placebo using a crossover design. More than 300 patients were included in this study, which ultimately showed a significant improvement in progression-free survival in patients taking vandetanib. Based on these results, the Oncology Drug Advisory Committee (ODAC) of the Food and Drug Administration (FDA) recommended that vandetanib be approved for the treatment of patients with unresectable locally advanced or metastatic medullary thyroid cancer.

Upregulation of endocrine gland-derived vascular endothelial growth factor in papillary thyroid cancers displaying infiltrative patterns, lymph node metastases, and BRAF mutation

BACKGROUND

Endocrine gland-derived vascular endothelial growth factor (Prok1) and prokineticin 2 (Prok2) are involved in the organ-specific regulation of angiogenesis, which is a crucial step toward cancer progression in most tumors, including those of thyroid gland. The oncogene BRAF V600E mutation is associated with poor clinical outcome of papillary thyroid cancer (PTC) and can independently predict its recurrence.

DESIGN

Our hypothesis was that Prok1 and Prok2 expression levels associated with BRAF mutations can be prognostic factors for PTC outcome. Prok1 and Prok2 were examined in PTC, a cell line derived from a human PTC (designated FB-2), euthyroid multinodular goiter (MNG), Graves' disease (GD), and contralateral normal thyroid (NT) tissues from PTC cases. We evaluated BRAF mutation and its relationship with Prok1 expression pattern in PTC.

METHODS

We studied Prok1 and Prok2 mRNAs by real-time polymerase chain reaction and BRAF mutation by mutant allele-specific polymerase chain reaction amplification. Formalin-fixed, paraffin-embedded blocks of PTC and NT were used for the immunohistochemical determination of Prok1 using anti-endocrine gland vascular endothelial growth factor primary antibody.

RESULTS

Prok1 and Prok2 transcripts were both present in thyroid tissues, and Prok1 was differentially expressed in PTC compared to MNG, GD, and NT. Prok1 mRNA levels were very low in NT and MNG and significantly higher in PTC, FB-2, and GD (p<0.05). Prok1 protein was almost undetectable in NT but was highly expressed in all PTC samples having an infiltrative pattern of growth and lymph node metastases ( p<0.05). Further, the expression of Prok1 in PTC was associated with 60% of the samples being positive for the BRAF mutation ( p<0.05).

CONCLUSIONS

We found that Prok1 is significantly increased in PTC, and its expression in PTC is related to BRAF mutation. These results suggest that Prok1 could be a new useful marker for thyroid cancer progression. Prok1 therefore could also be a potential target for novel therapeutic strategies, although the lack of functional data suggests caution against generalization of this assumption

Response to sorafenib at a low dose in patients with radioiodine-refractory pulmonary metastases from papillary thyroid carcinoma

BACKGROUND

Sorafenib has shown promise in the treatment of patients with advanced or metastatic thyroid carcinoma. However, the optimal dose has not been established and data on Chinese population are not available. We conducted a study to assess the responses to sorafenib at a low dose of 200 mg twice daily in patients with progressive radioiodine-refractory pulmonary metastases from papillary thyroid carcinoma (PTC).

PATIENTS AND METHODS

Eligible patients received sorafenib 200 mg orally twice daily. Responses were assessed using Response Evaluation Criteria in Solid Tumors and adverse events were assessed periodically. The end points included response rate and progression-free survival.

RESULTS

Nine patients with radioiodine-refractory PTC were enrolled in the study and treated for a minimum of 13 weeks. The objective partial response rate was 33%. The stable disease rate was 44%. The mean progression-free survival was 42 weeks (95% confidence interval, 29.5 to 53.9). Two patients showed disease progression, and one of them died at 4 months after beginning of treatment. There was a marked and rapid change in the serum thyroglobulin level after start of treatment, with a mean decrease of 60% within 12 weeks, consistent with radiographic findings. Although the types of toxicities were consistent with other sorafenib trials, their severity was relatively mild. None of the patients discontinued sorafenib or reduced their dose because of treatment-related adverse events.

CONCLUSION

Sorafenib at a dose of 200 mg twice daily has a potential therapeutic effect and is well tolerated in Chinese patients with PTC and radioiodine-refractory pulmonary metastases. Further study is warranted with a larger cohort of patients.

Anaplastic thyroid cancer: Clinical outcomes with conformal radiotherapy

BACKGROUND

The aim of this study was to review institutional outcomes for anaplastic thyroid cancer treated with conformal 3-dimensional radiotherapy (3DRT) or intensity-modulated radiotherapy (IMRT).

METHODS

In all, 53 consecutive patients were analyzed. Thirty-one (58%) patients were irradiated with curative intent. Median radiation dose was 55 Gray (Gy; range, 4-70 Gy). Thirteen (25%) patients received IMRT to a median 60 Gy (range, 39.9-69.0 Gy). Thirty-nine (74%) patients received chemotherapy with radiation.

RESULTS

The Kaplan-Meier estimate of overall survival (OS) at 1 year for definitively irradiated patients was 29%. Patients without distant metastases receiving >or=50 Gy had superior survival outcomes; 5 such patients had no evidence of disease at last follow-up. Use of IMRT versus 3DRT did not influence toxicity.

CONCLUSIONS

Outcomes for anaplastic thyroid cancer treated with 3DRT or IMRT remain equivalent to historical results. Healthy patients with localized disease who tolerate full dose irradiation can potentially enjoy prolonged survival. Biologically targeted radiosensitization merits prioritized investigation.

Enhanced photodynamic effect of cobalt(III) dipyridophenazine complex on thyrotropin receptor expressing HEK293 cells

Ternary cobalt(III) complexes [CoL(B)] (1-3) of a trianionic tetradentate phenolate-based ligand (L) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyridoquinoxaline (dpq in 2) and dipyridophenazine (dppz in 3) are synthesized, characterized from X-ray crystallographic, analytical and spectral techniques, and their utility in photodynamic therapy (PDT) of thyroid diseases caused by TSH receptor dysfunction is probed. The complexes display a visible spectral band within the PDT spectral window at ~690 nm. Photodynamic potential was estimated through DNA cleavage activity of the dpq and dppz complexes in UV-A light of 365 nm and red light of 676 nm. The reactions proceed via the hydroxyl radical pathway. The complexes retain their DNA photocleavage activity in red light under anaerobic conditions, a situation normally prevails in hypoxic tumor core. Investigation into the photocytotoxic potential of these complexes showed that the dppz complex 3 is approximately 4-fold more active in the HEK293 cells expressing human thyrotropin receptor (HEK293-hTSHR) than in the parental cell line and has an insignificant effect on an unrelated human cervical carcinoma cell line (HeLa). Photoexcitation of complex 3 in HEK293-hTSHR cells leads to damage hTSHR as evidenced from the decrease in cAMP formation both in absence and presence of hTSH and decrease in the TSHR immunofluorescence with a concomitant cytoplasmic translocation of the membrane protein, cadherin. The involvement of hTSHR is evidenced from the ability of complex 3 to bind to the extracellular domain of hTSHR (hTSHR-ECD) with a K(d) value of 81 nM and from the photocleavage of hTSHR-ECD.

Axitinib: The evidence of its potential in the treatment of advanced thyroid cancer

Introduction:

Thyroid cancer is a rare disease with an incidence of around 37,000 cases per year. However, its incidence is rising faster than many other cancers and for men this disease ranks highest overall in the rate of increase (2.4% annual increase) in cancer deaths. As the number of radioactive iodine-resistant thyroid cancers increases, the need for newer treatments has become more important. Axitinib is one of many new small molecule inhibitors of growth factor receptors that have shown promise in the treatment of many cancers. It targets the vascular endothelial growth factor receptors 1, 2 and 3.

Aims:

The goal of this article is to review the published evidence for the use of axitinib in the treatment of thyroid cancer and define its therapeutic potential.

Evidence review:

The major evidence of axitinib activity has appeared in meeting report abstracts. One phase II study has been published. This included patients with any histological type of thyroid cancer that was not amenable to treatment with radioactive iodine.

Clinical potential:

To date, in phase II clinical studies axitinib has demonstrated antitumor activity in advanced refractory thyroid cancer. As a monotherapy it resulted in a 30% response rate with another 38% of patients having stable disease. Axitinib appears to have a good tolerability profile, with hypertension being the most common grade 3 or greater side effect.

Thyroid stem cells and cancer

BACKGROUND

Thyroid gland development and function are essential for life, and recent findings indicate the presence of stem/progenitor cells within the thyroid gland as a potential source of tissue regeneration and cancer formation.

SUMMARY

This review summarizes the current knowledge on early differentiation of thyroid cells from embryonic stem cells and highlights exciting concepts and recent novel findings on adult thyroid stem/progenitor cells in the normal thyroid gland and in thyroid cancer. Other potential sources and markers of stem/progenitor cells in the thyroid include bone marrow, microchimerism, and embryological remnant-derived multifocal solid cell nests. Finally, we discuss new therapeutic strategies that target thyroid cancer stem cells.

CONCLUSIONS

Thyroid stem/progenitor cell populations are present in the normal and diseased thyroid gland. Advances in normal and cancer thyroid stem cell biology will be essential for future targeted therapies.

[(90)Yttrium-DOTA]-TOC response is associated with survival benefit in iodine-refractory thyroid cancer: long-term results of a phase 2 clinical trial

BACKGROUND

The authors aimed to explore the efficacy of (90)Yttrium-1,4,7,10-tetra-azacyclododecane N,N',N'',N'''-tetraacetic acid [(90)Y-DOTA]-Tyr(3)-octreotide (TOC) in advanced iodine-refractory thyroid cancer.

METHODS

In a phase 2 trial, the authors investigated biochemical response (assessed by serum thyroglobulin levels), survival, and the long-term safety profile of systemic [(90)Y-DOTA]-TOC treatment in metastasized iodine-refractory thyroid cancer. Adverse events were assessed according to the National Cancer Institute criteria. Survival analyses were performed by using multiple regression models.

RESULTS

A total of 24 patients were enrolled. A median cumulative activity of 13.0 GBq (range, 1.7-30.3 GBq) was administered. Response was found in 7 (29.2%) patients. Eight (33.3%) patients developed hematologic toxicity grade 1-3, and 4 (16.7%) patients developed renal toxicity grade 1-4. The median survival was 33.4 months (range, 3.6-126.8 months) from time of diagnosis and 16.8 months (range, 1.8-99.1 months) from time of first [(90)Y-DOTA]-TOC treatment. Response to treatment was associated with longer survival from time of diagnosis (hazard ratio [HR], 0.17; 95% confidence interval [CI], 0.03-0.92; P = .04) and from time of first [(90)Y-DOTA]-TOC therapy (HR, 0.20; 95% CI, 0.04-0.94; P = .04). The visual grade of scintigraphic tumor uptake was not associated with treatment response (odds ratio [OR], 0.98; 95% CI, 0.26-3.14; P = 1.00).

CONCLUSIONS

Response to [(90)Y-DOTA]-TOC in metastasized iodine-refractory thyroid cancer was associated with longer survival. Upcoming trials should aim to increase the number of treatment cycles.

Targeting epidermal growth factor receptor 1 signaling in human thyroid-stimulating hormone-independent thyroid carcinoma FRO cells results in a more chemosensitive and less angiogenic phenotype

BACKGROUND

Poorly differentiated and anaplastic thyroid cancers are aggressive malignancies unresponsive to standard treatments. The mechanisms responsible for the progression of thyroid tumors toward a thyroid-stimulating hormone (TSH)-independent phenotype are still under discussion, and a better understanding of them may provide novel molecular targets for the treatment of this disease. We evaluated the hypothesis that epithelial growth factor (EGF) signaling may play a role in favoring the loss of TSH dependency in human differentiated thyroid tumor cells.

METHODS

The sensitivity to EGF stimulation was evaluated in follicular thyroid carcinoma WRO cells that retain some features of thyroid cell differentiation and in undifferentiated TSH-independent thyroid carcinoma FRO cells.

RESULTS

It was observed that, while both cell lines are characterized by a similar EGF-dependent activation of the RAS/MAPK signaling pathway, only FRO cells exhibited a significant induction of phosphoAKT, cell proliferation, and migration as well as the up-regulation of vascular endothelial growth factor-A expression in response to EGF. On the other hand, the inhibition of epidermal growth factor receptor 1 signaling by its tyrosine kinase inhibitor, erlotinib, caused a selective down-regulation of FRO cell proliferation and induced a phenotype more sensitive to the proapoptotic activity of anthracyclins and taxoids. By contrast, the protracted stimulation of TSH-dependent WRO cells with EGF induced the loss of TSH dependency and the rearrangement of F-actin cytoskeleton.

CONCLUSIONS

These results suggest that the acquired sensitivity to EGF in these thyroid tumor cells may be responsible for the loss of differentiation in the transition toward a TSH-independent, invasive, and chemoresistant phenotype.

Antineoplastic agents. 552. Oxidation of combretastatin A-1: trapping the o-quinone intermediate considered the metabolic product of the corresponding phosphate prodrug

The very unstable (<10 min at rt) o-quinone 5 derived from the vicinal diphenol anticancer drug combretastatin A-1 (1) has been obtained by careful oxidation with NaIO4 and tetrabutylammonium bromide in water/dichloromethane. Immediate reaction with phenylenediamine (6) allowed o-quinone 5 to be trapped as the stable phenazine derivative 7. For further confirmation, 5 was also captured as a dimethoxyphenylenediamine-derived phenazine (11). Both phenazines 7 and 11 significantly inhibited (ED50 approximately 0.2 microg/mL) growth of the murine P388 lymphocytic leukemia cell line and provided a new SAR insight in the combretastatin series of naturally occurring anticancer drugs.

Mast cells and cancer--no longer just basic science

The incorporation of new anti-cancer kinase inhibitors within cancer management is rapidly increasing. Mast cells are sensitive to several of these new anti-cancer agents most notably to c-Kit inhibitors. As a result, studies investigating the role of mast cells in tumors may have direct clinical relevance and consequently, important clinical implications. Here we review some of the basic attributes of mast cells, especially those related to the new "targeted" drugs. Mast cell roles such as modulators of regulatory T-cells, inducers of angiogenesis and promoters of clot formation are discussed. We also review recent mouse tumor models and human pathological data which implicate mast cells as having both pro- and anti-tumor growth properties. These studies expose a complex, emerging picture of mast cell involvement in tumor biology. It seems that mast cell modulator drugs may improve the efficacy of anti-tumor therapy under certain circumstances, whilst under others, may negatively affect drug efficacy.