Role of extracellular vesicles in the progression, diagnosis and treatment of thyroid cancer (Review)

Comparative Proteomic Profiling of Ectosomes Derived from Thyroid Carcinoma and Normal Thyroid Cells Uncovers Multiple Proteins with Functional Implications in Cancer

Proteins carried by tumor-derived ectosomes play an important role in cancer progression, and are considered promising diagnostic markers. In the present study, a shotgun nanoLC–MS/MS proteomic approach was applied to profile and compare the protein content of ectosomes released in vitro by normal human thyroid follicular epithelial Nthy-ori 3-1 cells and human anaplastic thyroid carcinoma (TC) 8305C cells. Additionally, the pro-migratory and pro-proliferative effects of Nthy-ori 3-1- and 8305C-derived ectosomes exerted on the recipient cells were assessed in wound closure and Alamar Blue assays. A total of 919 proteins were identified in all replicates of 8305C-derived ectosomes, while Nthy-ori 3-1-derived ectosomes contained a significantly lower number of 420 identified proteins. Qualitative analysis revealed 568 proteins present uniquely in 8305C-derived ectosomes, suggesting their applicability in TC diagnosis and management. In addition, 8305C-derived ectosomes were able to increase the proliferation and motility rates of the recipient cells, likely due to the ectosomal transfer of the identified cancer-promoting molecules. Our description of ectosome protein content and its related functions provides the first insight into the role of ectosomes in TC development and progression. The results also indicate the applicability of some of these ectosomal proteins for further investigation regarding their potential as circulating TC biomarkers.

BRAFV600E Induction in Thyrocytes Triggers Important Changes in the miRNAs Content and the Populations of Extracellular Vesicles Released in Thyroid Tumor Microenvironment

Papillary thyroid cancer (PTC) is the most common endocrine malignancy for which diagnosis and recurrences still challenge clinicians. New perspectives to overcome these issues could come from the study of extracellular vesicle (EV) populations and content. Here, we aimed to elucidate the heterogeneity of EVs circulating in the tumor and the changes in their microRNA content during cancer progression. Using a mouse model expressing BRAF^V600E, we isolated and characterized EVs from thyroid tissue by ultracentrifugations and elucidated their microRNA content by small RNA sequencing. The cellular origin of EVs was investigated by ExoView and that of deregulated EV-microRNA by qPCR on FACS-sorted cell populations. We found that PTC released more EVs bearing epithelial and immune markers, as compared to the healthy thyroid, so that changes in EV-microRNAs abundance were mainly due to their deregulated expression in thyrocytes. Altogether, our work provides a full description of in vivo-derived EVs produced by, and within, normal and cancerous thyroid. We elucidated the global EV-microRNAs signature, the dynamic loading of microRNAs in EVs upon BRAF^V600E induction, and their cellular origin. Finally, we propose that thyroid tumor-derived EV-microRNAs could support the establishment of a permissive immune microenvironment.

Identification of DNA Repair-Related Genes Predicting Clinical Outcome for Thyroid Cancer

Recent studies have demonstrated the utility and superiority of DNA repair-related genes as novel biomarkers for cancer diagnosis, prognosis, and therapy. Here, we aimed to screen the potential survival-related DNA repair-related genes in thyroid cancer (TC). TCGA datasets were utilized to analyze the differentially expressed DNA repair-related genes between TC and nontumor tissues. The K–M approach and univariate analysis were employed to screen survival-related genes. RT-PCR was employed to examine the expression of DNA repair-related genes in TC samples and matched noncancer samples. CCK-8 analyses were used to determine cellular proliferation. Herein, our team discovered that the expression of four DNA repair-related genes was remarkably upregulated in TC samples in contrast to noncancer samples. Survival assays identified 14 DNA repair-related genes. In our cohort, we observed that the expression of TAF13 and DCTN4 was distinctly elevated in TC specimens in contrast to nontumor specimens. Moreover, knockdown of TAF13 and DCTN4 was observed to inhibit the TC cellular proliferation. Overall, the upregulation of TAF13 and DCTN4 is related to decreased overall survival in TC patients. Therefore, the assessment of TAF13 and DCTN4 expression may be useful for predicting prognosis in these patients.