Histopathological Assessment for Papillary Thyroid Carcinoma

METTL3-mediated m6A modification of MT1G inhibits papillary thyroid carcinoma cell growth and metastasis via Wnt/β-catenin pathway

BACKGROUND

Downregulation of metallothionein 1 G (MT1G) has been demonstrated in papillary thyroid carcinoma (PTC) tissues. However, the underlying molecular mechanisms of MT1G in PTC progression need to be further explored.

METHODS

MT1G and methyltransferase-like 3 (METTL3) mRNA levels were tested by quantitative real-time PCR. The protein levels of MT1G, METTL3, Wnt3A and β-catenin were measured by western blot. Cell proliferation, apoptosis, invasion and migration were measured by cell counting kit 8 assay, colony formation assay, EdU assay, flow cytometry, transwell assay and wound healing assay. MeRIP analysis was used to detect the MT1G methylation. The interaction between METTL3 and MT1G was evaluated using RIP assay and dual-luciferase reporter assay. A mouse xenograft model was also constructed to explore the roles of METTL3 and MT1G in vivo.

RESULTS

MT1G expression was downregulated in PTC, and its overexpression suppressed PTC cell growth, invasion and migration. METTL3-regulated m6A modification enhanced MT1G mRNA stability. Overexpression of METTL3 repressed PTC cell growth and metastasis, and this effect was reversed by MT1G knockdown. Besides, METTL3/MT1G axis could inhibit the activity of Wnt/β-catenin pathway. Meanwhile, METTL3 enhanced MT1G expression to suppress PTC tumor growth through Wnt/β-catenin pathway in vivo.

CONCLUSION

METTL3-mediated m6A modification of MT1G inhibited PTC cell growth and metastasis via inactivating the Wnt/β-catenin pathway.

MAP17 contributes to the tumorigenesis of papillary thyroid carcinoma by activating the AKT signaling pathway

OBJECTIVE

This study investigates the role of membrane-associated protein 17 (MAP17) and the Akt signaling pathway in the progression of papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

We conducted a series of in vitro experiments using PTC cell lines (HTori-3 and TPC-1). Cells were divided into three groups: control, MAP17 inhibitor negative control (NC), and MAP17 inhibitor treatment. Cell viability was assessed at 0, 24, 48, and 72 hours using the Cell Counting Kit-8 (CCK-8) assay. Apoptosis levels were measured by flow cytometry, and protein and mRNA expression of MAP17, phosphorylated Akt (p-AKT), and Akt were analyzed by Western blot and qRT-PCR.

RESULTS

Cell viability in the control, MAP17 inhibitor NC, and MAP17 inhibitor groups increased significantly over time (P < 0.05). Notably, in both HTori-3 and TPC-1 cells, the MAP17 inhibitor significantly reduced cell viability compared to the control and NC groups at 24, 48, and 72 hours (P < 0.05). Furthermore, apoptosis levels were significantly higher in the MAP17 inhibitor group compared to the control and NC groups (P < 0.05). Western blot and qRT-PCR analyses revealed that MAP17 and p-Akt protein and mRNA levels were significantly higher in the control and NC groups compared to the MAP17 inhibitor group (P < 0.05). However, no significant differences in total Akt protein or mRNA levels were observed across groups.

CONCLUSION

Our findings suggest that MAP17 and the Akt signaling pathway play a crucial role in promoting the progression of PTC. Inhibition of MAP17 suppresses cell viability and induces apoptosis, indicating that MAP17 may be a promising therapeutic target for PTC. The data also highlight the potential for targeting the MAP17-Akt axis in developing future treatments for PTC.

A novel computational pathology approach for identifying gene signatures prognostic of disease-free survival for papillary thyroid carcinomas

INTRODUCTION

Papillary thyroid carcinoma (PTC) is the most prevalent form of thyroid cancer, with the classical and follicular variants representing most cases. Despite generally favorable prognoses, approximately 10% of patients experience recurrence post-surgery and radioactive iodine therapy. Attempts to stratify risk of recurrence have relied on gene expression-based prognostic and predictive signatures with a focus on mutations of well-known driver genes, while hallmarks of tumor morphology have been ignored.

OBJECTIVES

We introduce a new computational pathology approach to develop prognostic gene signatures for PTC that is informed by quantitative features of tumor and immune cell morphology.

METHODS

We quantified nuclear and immune-related features of tumor morphology to develop a pathomic signature, which was then used to inform an RNA-expression signature model provides a notable advancement in risk stratification compared to both standalone and pathology-informed gene-expression signatures.

RESULTS

There was a 17.8% improvement in the C-index (from 0.605 to 0.783) for 123 cPTCs and 15% (from 0.576 to 0.726) for 38 fvPTCs compared to the standalone gene-expression signature. Hazard ratios also improved for cPTCs from 0.89 (0.67,0.99) to 4.43 (3.65,6.68) and fvPTC from 0.98 (0.76,1.32) to 2.28 (1.87,3.64). We validated the image-based risk model on an independent cohort of 32 cPTCs with hazard ratio 1.8 (1.534,2.167).

Hypoxia expedites the progression of papillary thyroid carcinoma by promoting the CPT1A-mediated fatty acid oxidative pathway

Hypoxia has been reported to promote the proliferation and migration of thyroid cancer, while the special mechanism was still unclear. HIF-1α/carnitine palmitoyl-transferase 1A (CPT1A) was found to be associated with papillary thyroid carcinoma (PTC) but the biological role of CPT1A in PTC was not explored. The effects of hypoxia and carnitine palmitoyl-transferase 1A (CPT1A) expression on PTC cells were determined by cell counting kit-8 assay, detection of oxidative stress, inflammation response and mitochondrial membrane motential (MMP). Oil Red O staining and the detection of free fatty acids were performed to assess the status of lipid metabolism. Flow cytometric analysis was performed to assess cell apoptosis. Quantitative polymerase chain reaction (qPCR) and western blot analysis were applied to investigate the expressions of CPT1A and HIF-1α and the molecules involved cell function. The expressions of CPT1A and HIF-1α were significantly increased in PTC cells with or without hypoxia treatment. CPT1A overexpression or silencing promoted or inhibited cell viability, and hypoxia further repressed cell viability. In addition, CPT1A overexpression alleviates hypoxia-induced increased oxidative stress, inflammation response and elevated MMP. CPT1A overexpression enhanced palmitic acid-induced decreased cell growth, enhanced the metabolic capacity of free fatty acid and suppressed cell apoptosis. Animal experiments showed that CPT1A overexpression promoted PTC tumor growth, reduced lipid deposition, oxidative stress and inflammation, as well as enhancing cell function indicators. However, CPT1A silencing showed the opposite effects both in vitro and in vivo. Hypoxia induces the high expression of HIF-1α/CPT1A, thereby reprogramming the lipid metabolism of PTC cells for adapting the hypoxia environment, meanwhile inhibiting the cell damage and apoptosis caused by oxidative stress.