Treatment of anaplastic thyroid cancer with tyrosine kinase inhibitors targeted on the tumor vasculature: initial experience in clinical practice.

Anaplastic thyroid cancer (ATC) is a rarely occurring refractory disease. While recent clinical trials have demonstrated the efficacy of tyrosine kinase inhibitor (TKI) therapy for ATC, evidence is scarce in clinical practice. In this study, we reviewed our initial experiences with TKI treatment in ATC patients with the aim of revealing the efficacy and safety of the same in clinical practice. We retrospectively reviewed our experiences with TKI treatment use in ATC patients diagnosed at our institute from 2014 to 2019. Changes in the patients' neutrophil-to-lymphocyte ratio (NLR) by TKI therapy introduction as well as their clinical factors to indicate the efficacy were examined. Seven patients showed no indication for TKI treatment, while 13 (65%) received treatment. The median duration of TKI treatment was 1.9 months. All patients died, and the overall survival period from diagnosis was 4.7 (95% confidence interval: 2.0-11.5) months. Adverse events ≥Grade 3 were observed commonly (92.3%), and resulted in the termination of TKI treatment in six cases (46.1%). Existence of multiple unfavorable characteristics (higher Prognostic Index) was associated with poor survival. The NLR decreased after the introduction of TKIs and increased again when treatment failed. The response rate to TKI among the ATC patients were approximately 30% in practice. Although the duration of the response was short, several patients demonstrated long survival durations when TKI treatment was provided after successful multidisciplinary treatment to control local disease. Decreases in high NLR values during treatment may suggest the continued effect of TKIs.

Lestaurtinib is a potent inhibitor of anaplastic thyroid cancer cell line models.

Anaplastic thyroid cancer (ATC) is a rare and lethal human malignancy with no known effective therapies in the majority of cases. Despite the use of conventional treatments such as chemotherapy, radiation and surgical resection, this disease remains almost universally fatal. In the present study, we identified the JAK2 inhibitor Lestaurtinib as a potent compound when testing against 13 ATC cell lines. Lestaurtinib demonstrated a potent antiproliferative effect in vitro at nanomolar concentrations. Furthermore, Lestaurtinib impeded cell migration and the ability to form colonies from single cells using scratch-wound and colony formation assays, respectively. Flow cytometry was used for cell cycle analysis following drug treatment and demonstrated arrest at the G2/M phase of the cell cycle, indicative of a cytostatic effect. In vivo studies using the chick chorioallantoic membrane xenograft models demonstrated that treatment with Lestaurtinib resulted in a significant decrease in endpoint tumor volume and vascularity using power Doppler ultrasound imaging. Overall, this study provides evidence that Lestaurtinib is a potent antiproliferative agent with potential antiangiogenic activity that warrants further investigation as a targeted therapy for ATC.

Expression of angiogenic switch, cachexia and inflammation factors at the crossroad in undifferentiated thyroid carcinoma with BRAF(V600E).

Cachexia is the result of complex metabolic alterations which cause morbidity and mortality in patients with advanced cancers including undifferentiated (anaplastic) thyroid carcinoma (ATC). ATC is a lethal disease with limited therapeutic options and unclear etiology for cachexia. We hypothesize that the BRAF(V600E) oncoprotein triggers microvascular endothelial cell tubule formation (in vitro angiogenesis) by means of factors which play a crucial role in angiogenic switch, inflammation/immune response and cachexia. We use human ATC cells and applied multiplex ELISA assay to screen for and measure angiogenic/cachectic and pro-inflammatory factors in the ATC-derived secretome. We find that vemurafenib anti-BRAF(V600E) therapy significantly reduces secreted VEGFA, VEGFC and IL6 protein levels compared to vehicle-treated ATC cells. As a result, the secretome from vemurafenib-treated ATC cells inhibits microvascular endothelial cell-related in vitro angiogenesis. Furthermore, ATC clinical samples express VEGFA, VEGFC and IL6 proteins. Our results suggest that angiogenic/cachectic and pro-inflammatory/immune response factors could play a crucial role in BRAF(V600E)-positive human ATC aggressiveness. Understanding the extent to which microenvironment-associated angiogenic factors participate in cachexia and cancer metabolism in advanced thyroid cancers will reveal new biomarkers and foster novel therapeutic approaches.