Wnt/ß-catenin signaling is a therapeutic target in anaplastic thyroid carcinoma.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is a highly aggressive malignancy that has consistently shown Wnt/ß-catenin (canonical) signaling activation in various study populations. There are currently no targetable treatments for BRAF-wildtype ATC and a lack of effective treatment for BRAFV600EATC. Our aim is to identify whether Wnt inhibitors could be potential therapeutic agents for ATC patients with limited treatment options. METHODS: In this Institutional Review Board-approved study, we utilize a cohort of 32 ATCs and 20 non-neoplastic multinodular goiters (MNG). We also use 4 ATC spheroid cell lines (THJ-16T, THJ-21T, THJ-29T, and THJ-11T) and two primary patient-derived ATC organoid cultures (VWL-T5 and VWL-T60). Finally, we use a murine xenograft mouse model of ATC for in vivo treatment studies. RESULTS: Using a large patient cohort, we demonstrate that this near-universal Wnt signaling activation is associated with ligand expression- rather than being mutationally-driven. We show that pyrvinium pamoate, a potent Wnt inhibitor, exhibits in vitro efficacy against both ATC cell lines and primary patient-derived ATC organoids VWL-T5 (p < 0.05) and VWL-T60 (p < 0.01) Finally, using a murine xenograft model of ATC, we show that pyrvinium significantly delays the growth of ATC tumors in THJ-16T (p < 0.005) and THJ-21T (p < 0.001). CONCLUSIONS: We tested Wnt inhibitor treatment, both in vitro and in vivo, as a potential novel therapy for this highly lethal disease. Future large-scale studies utilizing multiple Wnt inhibitors will lay the foundation for the development of these novel therapies for patients with ATC.

Utilizing Three-Dimensional Culture Methods to Improve High-Throughput Drug Screening in Anaplastic Thyroid Carcinoma.

Anaplastic thyroid carcinoma (ATC) is the most aggressive endocrine neoplasm, with a median survival of just four to six months post-diagnosis. Even with surgical and chemotherapeutic interventions, the five-year survival rate is less than 5%. Although combination dabrafenib/trametinib therapy was recently approved for treatment of the ~25% of ATCs harboring BRAFV600E mutations, there are no approved, effective treatments for BRAF-wildtype disease. Herein, we perform a screen of 1525 drugs and evaluate therapeutic candidates using monolayer cell lines and four corresponding spheroid models of anaplastic thyroid carcinoma. We utilize three-dimensional culture methods, as they have been shown to more accurately recapitulate tumor responses in vivo. These three-dimensional cultures include four distinct ATC spheroid lines representing unique morphology and mutational drivers to provide drug prioritization that will be more readily translatable to the clinic. Using this screen, we identify three exceptionally potent compounds (bortezomib, cabazitaxel, and YM155) that have established safety profiles and could potentially be moved into clinical trial for the treatment of anaplastic thyroid carcinoma, a disease with few treatment options.

HDAC inhibitors induce LIFR expression and promote a dormancy phenotype in breast cancer.

Despite advances in breast cancer treatment, residual disease driven by dormant tumor cells continues to be a significant clinical problem. Leukemia inhibitory factor receptor (LIFR) promotes a dormancy phenotype in breast cancer cells and LIFR loss is correlated with poor patient survival. Herein, we demonstrate that histone deacetylase inhibitors (HDACi), which are in phase III clinical trials for breast cancer, epigenetically induced LIFR and activated a pro-dormancy program in breast cancer cells. HDACi slowed breast cancer cell proliferation and reduced primary tumor growth. Primary breast tumors from HDACi-treated patients had increased LIFR levels and reduced proliferation rates compared to pre-treatment levels. Recent Phase II clinical trial data studying entinostat and azacitidine in metastatic breast cancer revealed that induction of several pro-dormancy genes post-treatment was associated with prolonged patient survival. Together, these findings suggest HDACi as a potential therapeutic avenue to promote dormancy, prevent recurrence, and improve patient outcomes in breast cancer.

Immunofluorescent staining of cancer spheroids and fine-needle aspiration-derived organoids.

Our organoid generation technique has allowed for the development of downstream organoid applications. Here, we detail an accessible, straightforward protocol for immunofluorescent staining and imaging of thyroid cancer organoids, particularly those with tumor de-differentiation. Immunofluorescence is a powerful tool to help understand the localization of cell types within organoids and determine the interactions between those cells. As organoids have been shown to recapitulate patient tumor morphology, immunofluorescent staining and imaging of organoids allows for enhanced understanding of near in vivo structures. For complete details on the use and execution of this protocol, please refer to Lee et al. (2020) and Vilgelm et al. (2020).

Obtaining patient-derived cancer organoid cultures via fine-needle aspiration.

Patient-derived tumor organoid cultures are an essential and innovative methodology for translational research. However, current techniques to establish these cultures are cumbersome, expensive, and often require irreplaceable clinical tissue from surgery or core biopsies. Fine-needle aspiration (FNA) provides a minimally invasive biopsy technique commonly performed in clinical settings. Here, we provide a protocol for FNA. We have found that FNA provides a cost-effective, rapid, and streamlined method for tissue acquisition for cancer organoid culture. For complete details on the use and execution of this protocol, please refer to Lee et al. (2020) and Vilgelm et al. (2020).

High-throughput drug screening of fine-needle aspiration-derived cancer organoids.

Generation of fine-needle aspiration (FNA)-derived cancer organoids has allowed us to develop a number of downstream applications. In this protocol, we start with organoids cultured in a semi-solid format. We dissociate organoids into single cells and then plate in a 384-well format for high-throughput drug screening. While this method must be fine-tuned for each individual organoid culture, it offers a format well suited for rapidly screening medium-sized drug/compound libraries (500-5,000 molecules) and generating dose-response curves to measure relative efficacy. For complete details on the use and execution of this protocol, please refer to Lee et al. (2020) and Vilgelm et al. (2020).

Fine-Needle Aspiration-Based Patient-Derived Cancer Organoids.

Patient-derived cancer organoids hold great potential to accurately model and predict therapeutic responses. Efficient organoid isolation methods that minimize post-collection manipulation of tissues would improve adaptability, accuracy, and applicability to both experimental and real-time clinical settings. Here we present a simple and minimally invasive fine-needle aspiration (FNA)-based organoid culture technique using a variety of tumor types including gastrointestinal, thyroid, melanoma, and kidney. This method isolates organoids directly from patients at the bedside or from resected tissues, requiring minimal tissue processing while preserving the histologic growth patterns and infiltrating immune cells. Finally, we illustrate diverse downstream applications of this technique including in vitro high-throughput chemotherapeutic screens, in situ immune cell characterization, and in vivo patient-derived xenografts. Thus, routine clinical FNA-based collection techniques represent an unappreciated substantial source of material that can be exploited to generate tumor organoids from a variety of tumor types for both discovery and clinical applications.

Novel three-dimensional cultures provide insights into thyroid cancer behavior.

Thyroid cancer has the fastest growing incidence of any cancer in the United States, as measured by the number of new cases per year. Despite advances in tissue culture techniques, a robust model for thyroid cancer spheroid culture is yet to be developed. Using eight established thyroid cancer cell lines, we created an efficient and cost-effective 3D culture system that can enhance our understanding of in vivo treatment response. We found that all eight cell lines readily form spheroids in culture with unique morphology, size, and cytoskeletal organization. In addition, we developed a high-throughput workflow that allows for drug screening of spheroids. Using this approach, we found that spheroids from K1 and TPC1 cells demonstrate significant differences in their sensitivities to dabrafenib treatment that closely model expected patient drug response. In addition, K1 spheroids have increased sensitivity to dabrafenib when compared to monolayer K1 cultures. Utilizing traditional 2D cultures of these cell lines, we evaluated the mechanisms of this drug response, showing dramatic and acute changes in their actin cytoskeleton as well as inhibition of migratory behavior in response to dabrafenib treatment. Our study is the first to describe the development of a robust spheroid system from established cultured thyroid cancer cell lines and adaptation to a high-throughput format. We show that combining 3D culture with traditional 2D methods provides a complementary and powerful approach to uncover drug sensitivity and mechanisms of inhibition in thyroid cancer.

Papillary thyroid carcinoma behavior: clues in the tumor microenvironment.

The prevalence of thyroid carcinoma is increasing and represents the most common endocrine malignancy, with papillary thyroid carcinoma (PTC) being the most frequent subtype. The genetic alterations identified in PTCs fail to distinguish tumors with different clinical behaviors, such as extra-thyroidal extension and lymph node metastasis. We hypothesize that the immune microenvironment may play a critical role in tumor invasion and metastasis. Computational immunogenomic analysis was performed on 568 PTC samples in The Cancer Genome Atlas using CIBERSORT, TIMER and TIDE deconvolution analytic tools for characterizing immune cell composition. Immune cell infiltrates were correlated with histologic type, mutational type, tumor pathologic T stage and lymph node N stage. Dendritic cells (DCs) are highly associated with more locally advanced tumor T stage (T3/T4, odds ratio (OR) = 2.6, CI = 1.4-4.5, P = 5.4 × 10-4). Increased dendritic cells (OR = 3.4, CI = 1.9-6.3, P = 5.5 × 10-5) and neutrophils (OR = 10.5, CI = 2.7-44, P = 8.7 × 10-4) significantly correlate with lymph node metastasis. In addition, dendritic cells positively correlate with tall cell morphology (OR = 4.5, CI = 1.6-13, P = 4.9 × 10-3) and neutrophils negatively correlate with follicular morphology (OR = 1.3 × 10-3, CI = 5.3 × 10-5-0.031, P = 4.1 × 10-5). TIDE analysis indicates an immune-exclusive phenotype that may be mediated by increased galectin-3 found in PTCs. Thus, characterization of the PTC immune microenvironment using three computational platforms shows that specific immune cells correlate with mutational type, histologic type, local tumor extent and lymph node metastasis. Immunologic evaluation of PTCs may provide a better indication of biologic behavior, resulting in the improved diagnosis and treatment of thyroid cancer.