Aurora激酶A通过磷酸化SREBP2调控胆固醇合成代谢促进食管鳞状细胞癌恶性进展OA

AIM:To investigate the regulatory role and molecular mechanism of Aurora kinase A(AURKA)on cholesterol metabolism in esophageal squamous cell carcinoma(ESCC)cells.METHODS:Cells with AURKA overex-pression,knockdown,and kinase-inactive mutant(D256A)were constructed in the human ESCC KYSE-150 cell line,along with empty vector/negative controls.Rescue experiments were performed by knocking down sterol regulatory element-binding protein 2(SREBP2).Oil Red O staining was used to evaluate lipid droplet accumulation,and colorimetric assays were performed to detect total cholesterol and free cholesterol levels.Filipin III staining was used to analyze membrane cholesterol distribution,and Western blots were conducted to examine the expression and phosphorylation of key mole-cules in the cholesterol synthesis pathway,SREBP2 and its downstream molecule 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMGCR).A subcutaneous in vivo xenograft tumor model was established in female BALB/c nude mice.The mice were randomly assigned to three groups(n=5)and inoculated with control cells,cells overexpressing wild-type AUR-KA,or cells expressing the D256A mutant.Tumor growth was monitored,and the expression of cholesterol metabolism-re-lated molecules in the tumors was analyzed.RESULTS:In KYSE-150 cells,overexpression of AURKA significantly in-creased lipid droplet accumulation,elevated total and free cholesterol levels,and affected membrane cholesterol distribu-tion(P<0.05),while the knockdown of AURKA produced the opposite effects.AURKA overexpression significantly upreg-ulated SREBP2 protein expression levels and its downstream molecule HMGCR(P<0.05).Knockdown of SREBP2 par-tially ameliorated the enhanced cholesterol synthesis,cell proliferation,and migration induced by AURKA overexpression(P<0.05).The kinase-inactive mutant D256A inhibited SREBP2 phosphorylation and the activation of its downstream lip-id metabolism pathway(P<0.05).In vivo experiments confirmed that tumor growth in nude mice inoculated with D256A mutant cells was significantly inhibited,intratumoral cholesterol content was significantly reduced,and the expression lev-els of SREBP2 and HMGCR were also significantly downregulated compared with the inoculation of cells overexpressing wild-type AURKA(P<0.05).CONCLUSION:In ESCC cells,AURKA phosphorylated and activated SREBP2 in a ki-nase activity-dependent manner,driving cholesterol synthesis metabolic reprogramming and thereby promoting cell prolif-eration and migration.