Laboratory of Molecular Diagnosis of Cancer, West China Hospital, Sichuan University, Chengdu, China; State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China;
Basic Medical Faculty, Dali Medical College, Dali, China; and.
Am J Physiol Gastrointest Liver Physiol. 2014 Jun 15;306(12):G1056-64. doi: 10.1152/ajpgi.00464.2013. Epub 2014 Apr 24.
Engineering cancer cells to express heterologous antigen α-gal and induce the destruction of tumor cells depending on the complement cascade may be a promising strategy of tumor therapy. However, the feasibility and effect of using α-gal to induce colorectal adenocarcinoma cell line cytolysis is not yet known. In this study, we evaluated α-gal expression's ability to sensitize human colorectal adenocarcinoma cell lines to complement attack in cell lines LoVo, SW620, and Ls-174T. Nearly all α-gal-expressing LoVo and SW620 cells were killed by normal human serum (NHS), but α-gal-expressing Ls-174T cells showed no significant lysis. We analyzed the expression levels of membrane-bound complement regulatory proteins (mCRPs) on the three cell lines, and their protective role in α-gal-mediated activation of the complement. LoVo showed no expression of any of the three proteins. CD59 was strongly expressed by SW620 and Ls-174T. CD46 and CD55 varied between the two cell lines. CD46 on SW620 was only half the intensity of CD46 on Ls-174T. Ls-174T showed a notable expression of CD55, while expression of CD55 on SW620 was not detected. The sensitivity of Ls-174T expressing α-gal to NHS greatly increased following the downregulation of CD46 and CD55 with short hairpin RNA (shRNA). However, there is no increase in cell killing when CD59 expression was diminished. Our findings suggest that the use of α-gal as antigen to induce tumor cell killing may be a potential therapeutic strategy in colon cancer and that CD55 plays a primary role in conferring resistance to lysis.
将癌细胞工程化表达异源抗原α-gal，并依靠补体级联诱导肿瘤细胞破坏，这可能是一种有前途的肿瘤治疗策略。然而，利用α-gal 诱导结直肠腺癌细胞系裂解的可行性和效果尚不清楚。在本研究中，我们评估了α-gal 表达在使人类结直肠腺癌细胞系 LoVo、SW620 和 Ls-174T 对补体攻击敏感方面的能力。几乎所有表达α-gal 的 LoVo 和 SW620 细胞都被正常人血清 (NHS) 杀死，但表达α-gal 的 Ls-174T 细胞没有明显的裂解。我们分析了三种细胞系上膜结合补体调节蛋白 (mCRP) 的表达水平，及其在α-gal 介导的补体激活中的保护作用。LoVo 未表达三种蛋白中的任何一种。SW620 和 Ls-174T 强烈表达 CD59。CD46 和 CD55 在两种细胞系之间存在差异。SW620 上的 CD46 只有 Ls-174T 上 CD46 的一半强度。Ls-174T 明显表达 CD55，而 SW620 上则未检测到 CD55 的表达。用短发夹 RNA (shRNA) 下调 CD46 和 CD55 后，表达α-gal 的 Ls-174T 对 NHS 的敏感性大大增加。然而，当 CD59 的表达减少时，细胞杀伤并没有增加。我们的研究结果表明，利用α-gal 作为抗原诱导肿瘤细胞杀伤可能是结肠癌的一种潜在治疗策略，而 CD55 在赋予抗裂解能力方面起着主要作用。
