Fumarate-1 Mediates the Regulation of Mitochondrial Homeostasis by PGC-1α to Promote Cell Pyroptosis and Inhibit the Progression of Thyroid Cancer.

Abstract

Thyroid cancer is a rare but increasingly prevalent form of cancer worldwide. The development and progression of thyroid cancer are associated with mitochondrial instability, which refers to alterations in the structure, function, and energy status of mitochondria. These alterations lead to an imbalance in mitochondrial metabolism, causing cellular damage and apoptosis. However, the molecular mechanisms underlying mitochondrial instability and thyroid cancer remain poorly understood. This study aimed to explore the molecular mechanism of delaying the progression of thyroid cancer by regulating mitochondrial homeostasis through fumarate 1-mediated PGC-1α in vitro. Human papillary thyroid carcinoma cell lines (TPC-1 and K-1) and a normal thyroid cell line (Nthy-ori 3-1) were cultured in this study. TPC-1 cells and K-1 cells were separately transfected with oveRNA-FH1 and oveRNA-NC, designated as the oveRNA-FH1 group, oveRNA- NC group, TPC-1 group, and Nthy-ori 3-1 group. Various assays were performed to assess cell viability, proliferation capacity, invasion and migration abilities, as well as mitochondrial morphology changes and the expression of relevant factors. qRT-PCR and Western blot analysis were carried out to analyze the expression changes of PGC-1α, mitochondrial dynamics-related factors, and pyroptosis genes. The goal of these experiments was to evaluate the impact of FH1 on mitochondrial instability and elucidate the specific mechanisms underlying thyroid cancer and mitochondrial instability. The results of this study demonstrated that FH1 expression was significantly downregulated in thyroid papillary carcinoma cell lines compared to the normal thyroid cell line. Overexpression of FH1 reduced cell viability and inhibited cell proliferation rate in TPC-1 cells. Furthermore, FH1 overexpression suppressed cell invasion and migration abilities. Abnormal mitochondrial morphological changes were observed in TPC-1 and K-1 cells, whereas FH1 overexpression resulted in relatively normal mitochondria. FH1 overexpression also affected the expression of fusion and fission genes, promoting fission and inhibiting fusion in thyroid cancer cells. Moreover, FH1 overexpression led to increased inflammation and pyroptosis. These conclusions were further verified by in vitro tumor formation experiments. FH1 promoted thyroid cancer progression by regulating mitochondrial homeostasis via the PGC-1α-dependent pathway, which affected pyroptosis and apoptosis.