Molecular Mechanism of Circ_0088300-BOLL Interaction Regulating Mitochondrial Metabolic Reprogramming and Involved in Gastric Cancer Growth and Metastasis

This study aims to investigate the effect and molecular mechanism of the interaction between circRNA circ_0088300 and the RNA binding protein (RBP) BOLL on the growth and metastasis of gastric cancer. A prognostic risk model was established by screening differentially expressed RBP genes from the TCGA database, and BOLL was identified as a critical RBP. Gene Set Enrichment analysis (GSEA) showed that BOLL was associated with mitochondrial function. The upregulation fold change of circ_0088300 was the highest in the GSE93541 data set, and the RPISeq database confirmed its binding relationship with BOLL. In vitro experiments showed that BOLL regulates mitochondrial metabolism and cancer cell function and circ_0088300 upregulates the expression level of BOLL. In vivo experiments demonstrated that knocking down circ_0088300 can inhibit tumor growth and metastasis, whereas overexpression of BOLL can reverse this effect. In conclusion, we have reached a preliminary conclusion that upregulation of BOLL by circ_0088300 promotes gastric cancer growth and metastasis by promoting mitochondrial metabolic reprogramming.

Effects of β-Sitosterol from Corn Silk on TGF-β1-Induced Epithelial-Mesenchymal Transition in Lung Alveolar Epithelial Cells

Pulmonary fibrosis is a chronic lung disease characterized by abnormal accumulation of the extracellular matrix (ECM). Chronic damage of the alveolar epithelium leads to a process called "epithelial-mesenchymal transition" (EMT) and increases synthesis and deposition of ECM proteins. Therefore, inhibition of EMT might be a promising therapeutic approach for the treatment of pulmonary fibrosis. β-Sitosterol is one of the most abundant phytosterols in the plant kingdom and the major constituent in corn silk, which is derived from the stigma and style of maize (Zea mays). In this study, we elucidated that β-sitosterol inhibited transforming growth factor-β1 (TGF-β1)-induced EMT and consequently had an antifibrotic effect. β-Sitosterol (1-10 μg/mL) significantly downregulated the TGF-β1-induced fibrotic proteins, such as collagen, fibronectin, and α-smooth muscle actin in human alveolar epithelial cells (p < 0.01). After 24 h, relative wound density (RWD) was increased in TGF-β1 treated group (82.16 ± 5.70) compare to the control group (64.63 ± 2.21), but RWD was decreased in β-sitosterol cotreated group (10 μg/mL: 71.54 ± 7.39; 20 μg/mL: 65.69 ± 6.42). In addition, the changes of the TGF-β1-induced morphological shape and protein expression of EMT markers, N-cadherin, vimentin, and E-cadherin, were significantly blocked by β-sitosterol treatment (p < 0.01). The effects of β-sitosterol on EMT were found to be associated with the TGF-β1/Snail pathway, which is regulated by Smad and non-Smad signaling pathways. Taken together, these findings suggest that β-sitosterol can be used to attenuate pulmonary fibrosis through suppression of EMT by inhibiting the TGF-β1/Snail pathway.