Background: Chimeric antigen receptor T cells (CAR-Ts) have demonstrated remarkable efficacy in hematological cancers but have not yet translated in treating solid tumors. The significant hurdles limiting CAR-T therapy were from a paucity of differentially expressed cell surface molecules on solid tumors that can be safely targeted. Here, we present TSH receptor (TSHR) as a putative target for CAR-T therapy of differentiated thyroid cancer (DTC). Methods: We undertook a large-scale screen on thyroid cancer tissues and multiple internal organs through bioinformatical analysis and immunohistochemistry to date TSHR expression. Using 3 previously described monoclonal antibodies, we generated 3 third-generation CAR-Ts. We tested anti-TSHR CAR-T in vitro activity by T-cell function and killing assay. Then we tested preclinical therapeutical efficacy in a xenograft mouse model of DTC and analyzed mice’s physical conditions and histological abnormalities to evaluate anti-TSHR CAR-T’s safety. Results: TSHR is highly and homogeneously expressed on 90.8% (138/152) of papillary thyroid cancer, 89.2% (33/37) of follicular thyroid cancer, 78.2% (18/23) of cervical lymph node metastases, and 86.7% of radioactive iodine resistance diseases. We developed 3 novel anti-TSHR CAR-Ts from monoclonal antibodies M22, K1-18, and K1-70; all 3 CAR-Ts mediate significant antitumor activity in vitro. Among these, we demonstrate that K1-70 CAR-T can have therapeutical efficacy in vivo, and no apparent toxicity has been observed. Conclusion: TSHR is a latent target antigen of CAR-T therapy for DTC. Anti-TSHR CAR-T could represent a therapeutic option for patients with locoregional relapsed or distant metastases of thyroid cancer and should be tested in carefully designed clinical trials.

Papillary thyroid cancer (PTC) remains the most common endocrine malignancy, despite marked achieves in recent decades, and the mechanisms underlying the pathogenesis and progression for PTC are incompletely elucidated. Accumulating evidence show that γ-glutamylcyclotransferase (GGCT), an enzyme participating in glutathione homeostasis and is elevated in multiple types of tumors, represents an attractive therapeutic target. Using bioinformatics, immunohistochemistry, qRT-PCR, and Western blot assays, we found that GGCT expression was upregulated in PTC and correlated with more aggressive clinicopathological characteristics and worse prognosis. GGCT knockdown inhibited the growth and metastasis ability of PTC cells both in vitro and in vivo and reduced the expression of mesenchymal markers (N-cadherin, CD44, MMP2, and MMP9) while increasing epithelial marker (E-cadherin) in PTC cells. We confirmed binding of microRNA-205-5p (miR-205-5p) on the 3′-UTR regions of GGCT by dual-luciferase reporter assay and RNA-RNA pull-down assay. Delivery of miR-205-5p reversed the pro-malignant capacity of GGCT both in vitro and in vivo. Lastly, we found that GGCT interacted with and stabilized CD44 in PTC cells by co-immunoprecipitation and immunohistochemistry assays. Our findings illustrate a novel signaling pathway, miR-205-5p/GGCT/CD44, that involves in the carcinogenesis and progression of PTC. Development of miR-205-mimics or GGCT inhibitors as potential therapeutics for PTC may have remarkable applications.

Breast cancer (BC) poses one of the major threats to female's health worldwide. Immune infiltration in BC is a key representative of the tumor microenvironment and has been proven highly relevant for prognosis. The role of the FREM1 (FRAS1‐Related Extracellular Matrix 1) gene in carcinoma has not studied, moreover, the underlying mechanism remains largely unknown. This study aims to investigate the expression profile and potential action of FREM1 on BC progression. We applied series of bioinformatic methods as well as immunohistochemistry (IHC) and immunofluorescence (IF) to analyze FREM1 expression profile, its relationship with clinicopathological characteristics, impact on clinical outcomes, relevant functions, correlation with immune infiltration in BC. The results demonstrated that FREM1 had a dramatically reduced expression in BC tissues, possessed an inverse correlation with stage, age, and metastasis, and exhibited a higher level in invasive lobular breast carcinoma than in ductal one. Furthermore, decreased FREM1 expression was often associated with estrogen receptor (ER)/progesterone receptor (PR) negative and triple negative breast carcinoma (TNBC) status while human epidermal growth factor 2 (Her‐2) positive status, and considerably correlated with a worse overall survival (OS) and recurrence‐free survival (RFS). Meanwhile, the univariate/multivariate Cox model revealed that low‐FREM1 expression can be an independent prognostic factor for BC. Additionally, FREM1 was mainly involved in the cell metabolism and immune cells infiltration. Moreover, IHC and IF demonstrated a positive correlation of its expression with the immune infiltrating levels of CD4⁺, CD8⁺ T cells, and CD86⁺ M1 macrophages while a negative correlation with CD68⁺ pan‐macrophages and CD163⁺ M2 macrophages. These findings suggest that FREM1 can be a potential biomarker for evaluating the immune infiltrating status, and the BC prognosis.