Department of Pathogenic Biology and Immunology, Medical School, Southeast University, Nanjing 210009, China.
Department of General Surgery, Zhongda Hospital Affiliated to Southeast University, Nanjing 210009, China.
Biomed Pharmacother. 2020 Dec;132:110804. doi: 10.1016/j.biopha.2020.110804. Epub 2020 Oct 2.
Colorectal cancer (CRC), initiated and maintained by colorectal cancer stem cells (CCSCs), ranks the third most common cancers and has drawn wide attentions worldwide. Therefore, targeting clearance of CCSCs has become an important strategy of CRC immunotherapy. Mucin1 (MUC1) is a tumor-associated cell surface antigen of CRC, but its role in CCSC vaccine remains unclear. In the study, we demonstrated that MUC1 may be a dominant antigen to exert antitumor immunity in CCSC vaccine. First, CCSCs were enriched from CT26 cell line via a serum-free sphere formation approach, and were identified by detecting expression of CD133, ALDH, and ALCAM. Then, the isolated CCSCs were frozen for 30 min and thawed for 30 min to prepare the cell lysate. The specific anti-MUC1 antibody was added to the cell lysate to neutralize the dominant antigen MUC1. Finally, mice were subcutaneously immunized with the cell lysate, followed by a challenge with CT26 cells at one week after final vaccination. Attractively, CCSC vaccine significantly activated the NK cells, T cells, and B cells, resulting in inhibiting the tumor growth via a target killing of CCSCs as evidenced by a decrease of CD133cells in tumor compared to CCSC vaccine with specific anti-MUC1 antibody. In addition, CCSC vaccine reduced expression of inflammatory factors in vaccinated mice. As expected, neutralizing antibody against MUC1 significantly impaired the antitumor efficacy of CCSC vaccine. Overall, CCSC vaccine could serve as a potent vaccine for CRC immunotherapy. The surface dominant antigen MUC1 may play a key role in regulating immunogenicity of CCSCs.
结直肠癌（CRC）由结直肠肿瘤干细胞（CCSCs）引发和维持，其发病率在所有癌症中排名第三，引起了全球广泛关注。因此，清除 CCSCs 已成为 CRC 免疫治疗的重要策略。黏蛋白 1（MUC1）是 CRC 的一种肿瘤相关细胞表面抗原，但它在 CCSC 疫苗中的作用尚不清楚。在本研究中，我们证实 MUC1 可能是 CCSC 疫苗发挥抗肿瘤免疫的主要抗原。首先，我们通过无血清球形成方法从 CT26 细胞系中富集 CCSCs，并通过检测 CD133、ALDH 和 ALCAM 的表达来鉴定 CCSCs。然后，将分离的 CCSCs 冷冻 30 分钟，然后解冻 30 分钟，以制备细胞裂解物。将特异性抗 MUC1 抗体添加到细胞裂解物中，以中和主要抗原 MUC1。最后，在最后一次接种后一周，通过皮下免疫小鼠，用 CT26 细胞进行攻击。令人欣喜的是，CCSC 疫苗显著激活 NK 细胞、T 细胞和 B 细胞，通过靶向杀伤 CCSCs 抑制肿瘤生长，与用特异性抗 MUC1 抗体的 CCSC 疫苗相比，肿瘤中 CD133 细胞减少。此外，CCSC 疫苗降低了接种小鼠中炎症因子的表达。不出所料，抗 MUC1 的中和抗体显著削弱了 CCSC 疫苗的抗肿瘤功效。总之，CCSC 疫苗可为 CRC 免疫治疗提供一种有效疫苗。表面主要抗原 MUC1 可能在调节 CCSCs 的免疫原性方面发挥关键作用。
