Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota.
Department of Immunology, Mayo Clinic, Rochester, Minnesota.
Clin Cancer Res. 2021 Jun 15;27(12):3280-3290. doi: 10.1158/1078-0432.CCR-20-1888. Epub 2021 Feb 8.
The apolipoprotein B mRNA editing enzyme catalytic polypeptide (APOBEC) family protects against infection by degrading incoming viral genomes through cytosine deamination. Here, we review how the potential to unleash these potent DNA mutagens comes at a price as APOBEC DNA mutagenesis can contribute to development of multiple types of cancer. In addition, because viral infection induces its expression, APOBEC is seen as the enemy of oncolytic virotherapy through mutation of the viral genome and by generating virotherapy-resistant tumors. Therefore, overall APOBEC in cancer has received very poor press. However, we also speculate how there may be silver linings to the storm clouds (kataegis) associated with APOBEC activity. Thus, although mutagenic genomic chaos promotes emergence of ever more aggressive subclones, it also provides significant opportunity for cytotoxic and immune therapies. In particular, the superpower of cancer immunotherapy derives in part from mutation, wherein generation of tumor neoantigens-neoantigenesis-exposes tumor cells to functional T-cell repertoires, and susceptibility to immune checkpoint blockade. Moreover, APOBECs may be able to induce suprathreshold levels of cellular mutation leading to mitotic catastrophe and direct tumor cell killing. Finally, we discuss the possibility that linking predictable APOBEC-induced mutation with escape from specific frontline therapies could identify mutated molecules/pathways that can be targeted with small molecules and/or immunotherapies in a Trap and Ambush strategy. Together, these considerations lead to the counterintuitive hypothesis that, instead of attempting to expunge and excoriate APOBEC activity in cancer therapy, it might be exploited-and even, counterintuitively, encouraged.
载脂蛋白 B mRNA 编辑酶催化多肽 (APOBEC) 家族通过胞嘧啶脱氨酶降解进入的病毒基因组,从而保护机体免受感染。在这里,我们回顾了这些潜在的强力 DNA 诱变剂是如何发挥作用的,因为 APOBEC 的 DNA 诱变作用可能导致多种类型的癌症的发生。此外,由于病毒感染会诱导其表达,APOBEC 通过突变病毒基因组和产生抗病毒治疗的肿瘤,被视为溶瘤病毒治疗的敌人。因此,总的来说,APOBEC 在癌症中的表现非常糟糕。然而,我们也推测了与 APOBEC 活性相关的“乌云背后的银边”(kataegis)可能存在的情况。因此,尽管突变的基因组混乱会促进更具侵袭性的亚克隆的出现,但也为细胞毒性和免疫治疗提供了巨大的机会。特别是,癌症免疫治疗的超级力量部分来自于突变,其中肿瘤新生抗原的产生(neoantigenesis)使肿瘤细胞暴露于功能性 T 细胞库中,并对免疫检查点阻断敏感。此外,APOBEC 可能能够诱导细胞突变达到阈上水平,导致有丝分裂灾难和直接杀死肿瘤细胞。最后,我们讨论了将可预测的 APOBEC 诱导的突变与逃避特定一线治疗联系起来的可能性,这可能会确定可以用小分子和/或免疫疗法靶向的突变分子/途径,从而实现“陷阱和伏击”策略。综上所述,这些考虑导致了一个反直觉的假设,即在癌症治疗中,与其试图消除和排斥 APOBEC 的活性,不如利用甚至反其道而行之,鼓励其发挥作用。