The Role of the CTBP2 Mediated Glycolytic Pathway in Nasopharyngeal Carcinoma Metastasis

Nasopharyngeal carcinoma (NPC), a highly aggressive and metastatic head and neck malignancy, exhibits invasion and metastasis closely linked to aerobic glycolysis. This study systematically analyzed the effect of CTBP2-mediated glycolytic signaling on NPC progression to elucidate the role of metabolic regulation in tumor development.
Immunohistochemistry was used to assess expression and localization of CTBP2 and ZEB1 in NPC tissues, metastatic lesions, and adjacent tissues. Both proteins were highly expressed in NPC and metastatic tissues, indicating their involvement in tumorigenesis and metastasis. Statistical analysis revealed significant differences between metastatic and primary NPC tissues, with CTBP2 expression correlating with T, N, and M stages. These findings suggest that CTBP2 contributes to NPC invasion and metastasis.
CTBP2 knockdown vectors were constructed, and HNE-1 cells were divided into control, si-NC, and si-CTBP2 groups. Cell viability was evaluated by CCK-8, invasion by Transwell, and metabolic alterations by extracellular acidification rate, lactate production, and glucose uptake. Compared with si-NC, si-CTBP2 significantly reduced proliferation and invasion. Glycolysis, glycolytic capacity, and reserve were decreased, while non-glycolytic acidification remained unchanged. 2-DG6P and lactate levels were reduced, indicating impaired glucose uptake and lactate generation. Collectively, CTBP2 knockdown suppressed glycolysis at the transcriptional level, reducing HNE-1 proliferation and invasion, suggesting its role in regulating glycolysis-related genes in NPC. qPCR confirmed that CTBP2 silencing also reduced ZEB1 mRNA, indicating transcriptional suppression of ZEB1.
To further validate this axis, HNE-1 cells were treated with si-NC, si-CTBP2, si-CTBP2+OE-NC, and si-CTBP2+OE-ZEB1. CCK-8 and wound-healing assays showed that si-CTBP2 significantly reduced proliferation and migration, while ZEB1 overexpression reversed these effects, supporting its role in promoting NPC progression.
A ZEB1 overexpression plasmid (ZEB1-pcDNA3.1(+)) was transfected into HNE-1 cells. Dual-luciferase reporter constructs (HK2-promoter-pmirGLO) were co-transfected with ZEB1-pcDNA3.1(+) into 293T cells. Overexpression significantly increased ZEB1 mRNA and enhanced HK2 promoter activity, confirming direct binding and transcriptional activation of HK2 by ZEB1, thereby facilitating glycolysis.
In vivo, HNE-1 xenograft models were established in nude mice with CTBP2 knockdown or control. Tumor growth was monitored, and molecular analyses performed. CTBP2 silencing markedly inhibited tumor growth, reduced CTBP2 and ZEB1 mRNA, increased E-cadherin protein, and decreased Vimentin, GLUT1, HK2, and ZEB1 expression.
In conclusion, CTBP2 regulates glycolysis and EMT in NPC through ZEB1 transcriptional control. Its silencing suppresses proliferation, invasion, and metastasis, highlighting CTBP2 as a potential therapeutic target.