Abstract：
Colorectal cancer is one of the most common malignant tumors worldwide, with high incidence and mortality rates making it a focus of research. Chemotherapy is a primary treatment modality for colon cancer, but chemotherapy resistance severely impacts treatment efficacy. MIF has been found to promote tumor progression and resistance in various cancers. This study aims to investigate the role of MIF in chemotherapy resistance in colon cancer and its potential mechanisms, particularly through the upregulation of CXCR7 expression, affecting the metabolism and drug sensitivity of colon cancer cells. The expression levels of MIF in colon cancer tissues and its association with patient prognosis were evaluated by analyzing TCGA and HPA data. Subsequently, the expression levels of MIF in colon cancer cell lines and resistant cell lines were detected by qRT-PCR and immunohistochemistry, and the effect of MIF on oxaliplatin sensitivity was assessed. The impact of MIF on the metabolic activity of colon cancer cells was measured using a cellular energy metabolism analyzer. Further experiments explored the mechanism by which MIF affects the metabolic activity of colon cancer cells through the upregulation of CXCR7 expression, and the role of CTCF in regulating CXCR7 transcription was validated by silencing CTCF. Finally, the effect of MIF on drug sensitivity of colon cancer cells was verified in a mouse xenograft tumor model. In this study, we found that the expression of MIF in colon cancer tissues was significantly higher than in normal tissues, and high MIF expression was associated with poor prognosis in patients. The expression levels of MIF in resistant colon cancer cell lines were significantly higher than in parental cell lines, and MIF overexpression significantly increased the resistance of colon cancer cells to oxaliplatin. Conversely, silencing MIF significantly reduced the IC50 value of resistant cells and increased apoptosis. MIF overexpression significantly increased the ECAR and OCR levels of colon cancer cells, while MIF knockdown significantly reduced these metabolic indicators. Further studies indicated that MIF affects the metabolic activity of colon cancer cells by upregulating CXCR7 expression. CTCF binding peaks at the CXCR7 promoter region and luciferase activity assays indicated that CTCF regulates CXCR7 transcription, and silencing CTCF significantly enhanced the sensitivity of colon cancer cells to oxaliplatin. In vivo experiments in mice showed that MIF silencing combined with oxaliplatin treatment significantly inhibited tumor growth and increased the necrotic area of tumor tissues. In conclusion, this study reveals the crucial role of MIF in chemotherapy resistance in colon cancer through the upregulation of CXCR7 expression, with CTCF playing an important regulatory role in this process. Our findings provide new theoretical insights and potential therapeutic targets for overcoming chemotherapy resistance in colon cancer. Future research should further explore the roles of MIF and CXCR7 in other types of cancers and the potential of MIF and CXCR7 as therapeutic targets.
摘要：
结直肠癌是世界范围内最常见的恶性肿瘤之一。高发病率和死亡率使其成为研究的焦点。化疗是结肠癌的主要治疗方式，但化疗耐药严重影响治疗效果。已经发现MIF在各种癌症中促进肿瘤进展和抗性。本研究旨在探讨MIF在结肠癌化疗耐药中的作用及其可能机制。特别是通过CXCR7表达的上调，影响结肠癌细胞的代谢和药物敏感性。通过分析TCGA和HPA数据评估结肠癌组织中MIF的表达水平及其与患者预后的关系。随后，用qRT-PCR和免疫组织化学方法检测结肠癌细胞株和耐药细胞株中MIF的表达水平,并评估了MIF对奥沙利铂敏感性的影响。使用细胞能量代谢分析仪测量MIF对结肠癌细胞代谢活性的影响。进一步的实验探索了MIF通过上调CXCR7表达影响结肠癌细胞代谢活性的机制,通过沉默CTCF验证了CTCF在调节CXCR7转录中的作用。最后,在小鼠移植瘤模型中验证了MIF对结肠癌细胞药物敏感性的影响。在这项研究中,我们发现MIF在结肠癌组织中的表达明显高于正常组织,MIF高表达与患者预后不良有关。MIF在结肠癌耐药细胞株中的表达水平显著高于亲本细胞株,MIF过表达显著增加结肠癌细胞对奥沙利铂的耐药性。相反，沉默MIF可显著降低耐药细胞的IC50值,增加细胞凋亡。MIF过表达显著增加结肠癌细胞的ECAR和OCR水平,而MIF敲低显著降低了这些代谢指标。进一步的研究表明，MIF通过上调CXCR7的表达影响结肠癌细胞的代谢活性。CTCF在CXCR7启动子区的结合峰和荧光素酶活性测定表明CTCF调控CXCR7转录,沉默CTCF可显著增强结肠癌细胞对奥沙利铂的敏感性。小鼠体内实验表明，MIF沉默联合奥沙利铂治疗可显着抑制肿瘤生长并增加肿瘤组织的坏死面积。总之,这项研究揭示了MIF通过上调CXCR7表达在结肠癌化疗耐药中的关键作用，CTCF在这一过程中发挥着重要的调节作用。我们的发现为克服结肠癌化疗耐药提供了新的理论见解和潜在的治疗靶点。未来的研究应进一步探讨MIF和CXCR7在其他类型癌症中的作用以及MIF和CXCR7作为治疗靶标的潜力。
