Background/Objectives: Hepatocellular carcinoma (HCC) therapies are limited by poor response, rapid resistance, and recurrence of aggressive disease. Sorafenib, a multi-tyrosine kinase inhibitor, can trigger β-catenin stabilization and activation, contributing to resistance. Overexpression of the chemokine receptor CXCR6 and its ligand CXCL16 and hyperactivation are implicated in HCC progression and β-catenin stabilization. We hypothesized that SBI-457, a small-molecule CXCR6 antagonist we developed, could disrupt CXCR6/β-catenin crosstalk and enhance sorafenib sensitivity.Methods: We tested SBI-457 alone and in combination with sorafenib in SK-Hep-1 xenograft models and a panel of human HCC cell lines. Tumor burden, β-catenin activation, and CXCR6 expression were assessed by tumor volume measurements, immunohistochemistry, Western blotting, and immunofluorescence. Soluble CXCL16 levels were quantified by ELISA, and cell death responses were evaluated using MTT assays.Results: In vivo, SBI-457 combined with sorafenib reduced normalized tumor volume by 55% compared to vehicle controls, modestly exceeding monotherapy effects, and attenuated sorafenib-induced β-catenin upregulation. In vitro, SBI-457 blocked nuclear accumulation of β-catenin and reversed sorafenib-induced increases in β-catenin levels. Enhanced cell death was observed in specific “responder” HCC cell lines (Hep-3B, SNU-398, JHH-5), which correlated with high intracellular β-catenin, secretion of soluble CXCL16, and expression of a high molecular weight form of CXCR6. In contrast, “non-responder” cell lines with conventional CXCR6 expression and low CXCL16 secretion showed no enhanced cell death response.Conclusions: CXCR6 antagonism with SBI-457 can modulate β-catenin activation and may help overcome sorafenib resistance in selected HCC models. These findings support further development of CXCR6 antagonists as single agents or combination therapies to improve treatment outcomes in HCC.
**背景/目的：** 肝细胞癌的治疗因疗效不佳、快速耐药及侵袭性疾病复发而受限。多酪氨酸激酶抑制剂索拉非尼可引发β-连环蛋白的稳定与激活，从而导致耐药。趋化因子受体CXCR6及其配体CXCL16的过表达与过度激活，与HCC进展及β-连环蛋白稳定化相关。我们推测，我们开发的小分子CXCR6拮抗剂SBI-457能够破坏CXCR6/β-连环蛋白的交互作用，并增强对索拉非尼的敏感性。 **方法：** 我们在SK-Hep-1异种移植模型及一组人HCC细胞系中，分别测试了SBI-457单药及其与索拉非尼联合使用的效果。通过肿瘤体积测量、免疫组织化学、蛋白质印迹和免疫荧光评估肿瘤负荷、β-连环蛋白激活及CXCR6表达。采用ELISA定量可溶性CXCL16水平，并使用MTT法评估细胞死亡反应。 **结果：** 在体内，与载体对照组相比，SBI-457联合索拉非尼使标准化肿瘤体积减少了55%，效果略优于单药治疗，并减弱了索拉非尼诱导的β-连环蛋白上调。在体外，SBI-457阻断了β-连环蛋白的核内积聚，并逆转了索拉非尼诱导的β-连环蛋白水平升高。在特定的"应答者"HCC细胞系（Hep-3B、SNU-398、JHH-5）中观察到细胞死亡增强，这与高水平的细胞内β-连环蛋白、可溶性CXCL16的分泌以及高分子量形式CXCR6的表达相关。相比之下，具有常规CXCR6表达和低CXCL16分泌的"非应答者"细胞系未显示出增强的细胞死亡反应。 **结论：** 使用SBI-457进行CXCR6拮抗可以调节β-连环蛋白的激活，并可能有助于在选定的HCC模型中克服索拉非尼耐药。这些发现支持进一步开发CXCR6拮抗剂作为单药或联合疗法，以改善HCC的治疗效果。
肿瘤(癌症)患者之家