Jiangsu Institute of Clinical Immunology, The First Affiliated Hospital of Soochow University, Suzhou, China.
Jiangsu Key Laboratory of Clinical Immunology, Soochow University, Suzhou, China.
Cancer Sci. 2023 Nov;114(11):4225-4236. doi: 10.1111/cas.15944. Epub 2023 Sep 3.
Ferroptosis, a newly discovered form of regulated cell death, has been reported to be associated with multiple cancers, including colorectal cancer (CRC). However, the underlying molecular mechanism is still unclear. In this study, we identified B7H3 as a potential regulator of ferroptosis resistance in CRC. B7H3 knockdown decreased but B7H3 overexpression increased the ferroptosis resistance of CRC cells, as evidenced by the expression of ferroptosis-associated genes (PTGS2, FTL, FTH, and GPX4) and the levels of important indicators of ferroptosis (malondialdehyde, iron load). Moreover, B7H3 promoted ferroptosis resistance by regulating sterol regulatory element binding protein 2 (SREBP2)-mediated cholesterol metabolism. Both exogenous cholesterol supplementation and treatment with the SREBP2 inhibitor betulin reversed the effect of B7H3 on ferroptosis in CRC cells. Furthermore, we verified that B7H3 downregulated SREBP2 expression by activating the AKT pathway. Additionally, multiplex immunohistochemistry was carried out to show the expression of B7H3, prostaglandin-endoperoxide synthase 2, and SREBP2 in CRC tumor tissues, which was associated with the prognosis of patients with CRC. In summary, our findings reveal a role for B7H3 in regulating ferroptosis by controlling cholesterol metabolism in CRC.
铁死亡是一种新发现的细胞程序性死亡方式,与多种癌症有关,包括结直肠癌(CRC)。然而,其潜在的分子机制尚不清楚。在本研究中,我们鉴定出 B7H3 是 CRC 中铁死亡抵抗的潜在调节因子。B7H3 敲低降低了 CRC 细胞的铁死亡抵抗能力,而 B7H3 过表达则增加了 CRC 细胞的铁死亡抵抗能力,这表现在铁死亡相关基因(PTGS2、FTL、FTH 和 GPX4)的表达和铁死亡的重要指标(丙二醛、铁负荷)的水平上。此外,B7H3 通过调节固醇调节元件结合蛋白 2(SREBP2)介导的胆固醇代谢来促进铁死亡抵抗。外源性胆固醇补充和 SREBP2 抑制剂 betulin 的处理均逆转了 B7H3 对 CRC 细胞铁死亡的影响。此外,我们证实 B7H3 通过激活 AKT 通路下调 SREBP2 的表达。此外,还进行了多重免疫组化分析,以显示 CRC 肿瘤组织中 B7H3、前列腺素内过氧化物合酶 2 和 SREBP2 的表达情况,其与 CRC 患者的预后相关。总之,我们的研究结果表明,B7H3 通过控制 CRC 中的胆固醇代谢来调节铁死亡。