Relationship between the upregulation of Notch1 signaling and the clinical characteristics of patients with papillary thyroid carcinoma in East Asia: a systematic review and meta-analysis

TMEM252 inhibits epithelial-mesenchymal transition and progression in papillary thyroid carcinoma by regulating Notch1 expression

BACKGROUND

Papillary thyroid carcinoma (PTC) accounts for about 85% of thyroid cancer cases. Transmembrane protein 252 (TMEM252) is a gene encoding a transmembrane protein that has only been reported to be associated with triple-negative breast cancer. Herein, we first elucidated the physiological roles and possible regulatory proteins of TMEM252 in PTC pathogenesis.

METHODS

Quantitative real-time polymerase chain reaction, western blot, and immunohistochemical analyses were utilized to ascertain the relative TMEM252 expression in PTC and surrounding normal tissues. Functional investigations involved CCK-8 viability assay, EdU incorporation assay for proliferation, transwell assays for migration and invasion, and an in vivo tumor development assessment to evaluate the TMEM252-mediated regulation of tumor formation.

RESULTS

Our results first revealed diminished TMEM252 transcript and protein expressions in PTC tissues and cell lines. TMEM252 overexpression suppressed cell proliferation through reducing p53, p21, and p16 expression. Conversely, TMEM252 depletion has opposite effects in PTC cells both in vivo. Additionally, the upregulation of TMEM252 demonstrated cell migration and invasion suppression by impeding the epithelial-mesenchymal transition (EMT) process via inhibition of the Notch pathway. Furthermore, overexpression of TMEM252 suppressed tumor growth in vivo.

CONCLUSION

Our study elucidates that TMEM252 suppresses PTC progression by modulating the Notch pathway. These findings underscore TMEM252 is a potential therapeutic target in managing PTC.

Single-cell sequencing reveals SATB2/NOTCH1 signaling promotes the progression of malignancy of epithelial cells from papillary thyroid cancer

Although most papillary thyroid cancers (PTCs) are deemed to have a favorable clinical course and outcome, some develop an aggressive biological behavior at diagnosis or during treatment. Single-cell RNA sequencing (scRNA-seq), which is based on quantifying the features of individual cells to resolve tumor tissue heterogeneity, was used to uncover gene regulatory relationships and trace the transcriptional trajectories underlying the malignant transformation. In this study, we performed single-cell sequencing on samples from four PTC patients and one benign thyroid tumor patient. These included two papillary thyroid microcarcinoma cancers (PTMC) patients, two age-matched advanced PTC patients with invading surrounding tissues, and one patient undergoing surgical treatment due to a benign thyroid tumor. We constructed a new PTC RNA spectrum using single-cell sequencing. Single-cell sequencing analysis indicated that there was a highly invasive subgroup in the PTC epithelial cells, the expression of SATB2 (special AT-rich binding protein-2) was related to the prognosis and clinical progress of PTC, and SATB2 could promote the proliferation, migration, and invasion of PTC cells. We found that NOTCH1 was the key target gene of SATB2, and the activation of the SATB2/NOTCH1 pathway was one of the reasons for the high carcinogenicity of this subgroup.

Cancer-associated fibroblasts: Origin, function, imaging, and therapeutic targeting

The tumor microenvironment (TME) is emerging as one of the primary barriers in cancer therapy. Cancer-associated fibroblasts (CAF) are a common inhabitant of the TME in several tumor types and play a critical role in tumor progression and drug resistance via different mechanisms such as desmoplasia, angiogenesis, immune modulation, and cancer metabolism. Due to their abundance and significance in pro-tumorigenic mechanisms, CAF are gaining attention as a diagnostic target as well as to improve the efficacy of cancer therapy by their modulation. In this review, we highlight existing imaging techniques that are used for the visualization of CAF and CAF-induced fibrosis and provide an overview of compounds that are known to modulate CAF activity. Subsequently, we also discuss CAF-targeted and CAF-modulating nanocarriers. Finally, our review addresses ongoing challenges and provides a glimpse into the prospects that can spearhead the transition of CAF-targeted therapies from opportunity to reality.

Notch Signaling in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system with a steadily rising incidence. The term "thyroid cancer" encompasses a spectrum of subtypes, namely papillary thyroid cancer, follicular thyroid cancer, anaplastic thyroid cancer, and medullary thyroid cancer. Each subtype differs histopathologically and in degrees of cellular differentiation, which may be in part due to signaling of the Notch pathway. The Notch pathway is an evolutionarily conserved signal transduction mechanism that regulates cell proliferation, differentiation, survival, stem cell maintenance, embryonic and adult development, epithelial-mesenchymal transition, and angiogenesis. Its role in cancer biology is controversial, as it has been shown to play both an oncogenic and tumor-suppressive role in many different types of cancers. This discordance holds true for each subtype of thyroid cancer, indicating that Notch signaling is likely cell type and context dependent. Whether oncogenic or not, Notch signaling has proven to be significantly involved in the tumorigenesis of thyroid cancer and has thus earned interest as a therapeutic target. Advancement in the understanding of Notch signaling in thyroid cancer holds great promise for the development of novel treatment strategies to benefit patients.

Expression of NOTCH1 in thyroid cancer is mostly restricted to papillary carcinoma

The NOTCH signaling is an evolutionarily conserved signaling pathway that regulates cell-cell interactions. NOTCH family members play a fundamental role in a variety of processes during development in particular in cell fate decisions. As other crucial factors during embryogenesis, NOTCH signaling is aberrantly reactivated in cancer where it has been linked to context-dependent effects. In thyroid cancer, NOTCH1 expression has been associated to aggressive features even if its in vivo expression within the entire spectrum of thyroid tumors has not definitively established. A series of 106 thyroid specimens including non-neoplastic lesions, benign and malignant tumors of common and rare histotypes, were investigated by immunohistochemistry to assess NOTCH1 expression. Extent of positivity and protein localization were investigated and correlated with clinical and morphological parameters. NOTCH1 positivity was predominantly associated with papillary carcinomas and only occasionally found in follicular carcinomas. Poorly differentiated and undifferentiated thyroid carcinomas showed only a partial positivity. NOTCH1 expression pattern also seemed differently distributed according to histotype. Our data confirm a role of NOTCH1 in thyroid cancer and highlight for the first time the specific involvement of this pathway in papillary carcinomas. Our data also indicate that other thyroid malignancies do not rely on NOTCH1 signaling for development and progression.