Exosomal circ-ZNF652 Mediates TGF-β1-Induced Epithelial-Mesenchymal Transition and Glycolytic Reprogramming to Promote Hepatocellular Carcinoma Progression

Abstract

Hepatocellular carcinoma (HCC) progression involves epithelial-mesenchymal transition (EMT) and glycolytic reprogramming induced by TGF-β1. The role of exosomal circular RNAs in coordinating these processes remains unclear. This study aims to investigate whether exosomal circ-ZNF652 is associated with TGF-β1-induced mesenchymal marker induction and glycolysis in HCC and elucidate the underlying mechanism. Exosomes were isolated from SMMC-7721 cells and characterized by TEM, NTA, and CD63 western blot. RT-qPCR measured circ-ZNF652 expression. Cell viability, migration, cycle, and apoptosis were assessed by MTT, wound healing, and flow cytometry. EMT and glycolysis proteins were detected by western blot. Glucose uptake, lactate, and HK/LDHA activities were measured. In vivo xenograft and rescue experiments with AKT/HIF-1α inhibitors were performed. TGF-β1 stimulation upregulated circ-ZNF652 in SMMC-7721 cells and their exosomes. Exosomal circ-ZNF652 was internalized by HCC cells and further enhanced TGF-β1-induced upregulation of EMT markers (Twist1, N-cadherin, vimentin, MMP-9). It also promoted cell proliferation, migration, S-phase entry, reduced apoptosis and Caspase-3 activity. Moreover, Exos circ-ZNF652 augmented TGF-β1-induced glycolysis as evidenced by increased glucose uptake, lactate secretion, HK/LDHA activities, and Glut-1/HIF-1α expression. In vivo, circ-ZNF652 overexpression significantly increased tumor volume (1286.5 vs 452.8 mm3) and weight (1.32 vs 0.48 g), along with elevated Ki-67, N-cadherin, HIF-1α, and p-AKT. Rescue experiments showed that AKT or HIF-1α inhibition reversed circ-ZNF652-mediated EMT and glycolysis. All differences were statistically significant (P<0.05). To sum up, exosomal circ-ZNF652 is associated with TGF-β1-induced mesenchymal phenotype acquisition and glycolysis via the AKT/HIF-1α pathway, promoting HCC progression. It represents a potential non-invasive biomarker and therapeutic target for HCC.