To interfere with cell function, many scientists rely on methods that target DNA or RNA due to the ease with which they can be applied. Proteins are usually the final executors of function but are targeted only indirectly by these methods. Recent advances in targeted degradation of proteins based on proteolysis-targeting chimaeras (PROTACs), ubiquibodies, deGradFP (degrade Green Fluorescent Protein) and other approaches have demonstrated the potential of interfering directly at the protein level for research and therapy. Proteins can be targeted directly and very specifically by antibodies, but using antibodies inside cells has so far been considered to be challenging. However, it is possible to deliver antibodies or other proteins into the cytosol using standard laboratory equipment. Physical methods such as electroporation have been demonstrated to be efficient and validated thoroughly over time. The expression of intracellular antibodies (intrabodies) inside cells is another way to interfere with intracellular targets at the protein level. Methodological strategies to target the inside of cells with antibodies, including delivered antibodies and expressed antibodies, as well as applications in the research areas of neurobiology, viral infections and oncology, are reviewed here. Antibodies have already been used to interfere with a wide range of intracellular targets. Disease-related targets included proteins associated with neurodegenerative diseases such as Parkinson’s disease (α-synuclein), Alzheimer’s disease (amyloid-β) or Huntington’s disease (mutant huntingtin [mHtt]). The applications of intrabodies in the context of viral infections include targeting proteins associated with HIV (e.g. HIV1-TAT, Rev, Vif, gp41, gp120, gp160) and different oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV) and Epstein-Barr virus, and they have been used to interfere with various targets related to different processes in cancer, including oncogenic pathways, proliferation, cell cycle, apoptosis, metastasis, angiogenesis or neo-antigens (e.g. p53, human epidermal growth factor receptor-2 [HER2], signal transducer and activator of transcription 3 [STAT3], RAS-related RHO-GTPase B (RHOB), cortactin, vascular endothelial growth factor receptor 2 [VEGFR2], Ras, Bcr-Abl). Interfering at the protein level allows questions to be addressed that may remain unanswered using alternative methods. This review addresses why direct targeting of proteins allows unique insights, what is currently feasible in vitro, and how this relates to potential therapeutic applications.

中文翻译：

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在细胞内应用抗体：神经生物学、病毒学和肿瘤学的原理和最新进展。


为了干扰细胞功能，许多科学家依赖于 DNA 或 RNA 靶向方法，因为它们易于应用。蛋白质通常是功能的最终执行者，但这些方法仅间接靶向。基于蛋白水解靶向嵌合体 (PROTAC)、泛素体、deGradFP（降解绿色荧光蛋白）和其他方法的蛋白质靶向降解的最新进展已经证明了在蛋白质水平上直接干扰研究和治疗的潜力。抗体可以直接且非常特异性地靶向蛋白质，但迄今为止在细胞内使用抗体被认为具有挑战性。然而，可以使用标准实验室设备将抗体或其他蛋白质递送到胞质溶胶中。电穿孔等物理方法已被证明是有效的，并且随着时间的推移得到彻底验证。细胞内抗体（胞内抗体）的表达是在蛋白质水平上干扰细胞内靶标的另一种方式。本文将总结用抗体靶向细胞内部的方法策略，包括递送抗体和表达抗体，以及在神经生物学、病毒感染和肿瘤学研究领域的应用。抗体已被用于干扰多种细胞内靶标。疾病相关靶标包括与神经退行性疾病相关的蛋白质，例如帕金森病（α-突触核蛋白）、阿尔茨海默病（淀粉样蛋白-β）或亨廷顿舞蹈病（突变亨廷顿蛋白 [mHtt]）。体内抗体在病毒感染中的应用包括靶向与 HIV 相关的蛋白质（例如 HIV1-TAT、Rev、Vif、gp41、gp120、gp160）和不同的肿瘤病毒，如人乳头瘤病毒（HPV）、乙型肝炎病毒（HBV）、丙型肝炎病毒（HCV）和 Epstein-Barr 病毒，它们已被用于干扰与癌症不同过程相关的各种靶标，包括致癌途径、增殖、细胞周期、细胞凋亡、转移、血管生成或新抗原（例如 p53、人表皮生长因子受体 2 [HER2]、信号转导器和转录激活剂） 3 [STAT3]、RAS 相关 RHO-GTPase B (RHOB)、cortactin、血管内皮生长因子受体 2 [VEGFR2]、Ras、Bcr-Abl)。在蛋白质水平上进行干扰可以解决使用替代方法可能无法回答的问题。这篇综述探讨了为什么直接靶向蛋白质可以带来独特的见解、目前在体外可行的方法，以及这与潜在的治疗应用有何关系。