State Key Laboratory of Virology and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
University of Chinese Academy of Sciences, Beijing, China.
J Med Virol. 2022 Dec;94(12):6000-6015. doi: 10.1002/jmv.28069. Epub 2022 Sep 1.
Oncolytic viruses (OVs), including oncolytic herpes simplex viruses (oHSVs), are promising therapeutics against cancer. Here, we report two ICP6-mutated HSVs (type I) generated by CRISPR/Cas9, rHSV1/∆RR (with ICP6 ribonucleotide reductase [RR] domain deleted) and rHSV1/∆ICP6 (with a complete deletion of ICP6), exhibiting potent antitumor efficacy against lung adenocarcinoma. Both the mutants showed strong cytotoxicity in vitro, comparable with the control viruses expressing intact ICP6, but in relatively lower titers. Moreover, these mutant viruses exhibited preferential killing ability against lung tumor cells rather than normal lung fibroblast cells. Further, unlike the control HSV-1 causing severe illness or death in the mouse model, the ICP6-mutated viruses did not induce significant pathogenicity but instead effectively reduced tumor burden in vivo and led to 100% survival of the animals, indicating notable antitumor activity and attenuated virulence. In addition, rHSV1/∆RR seemed to have even better antitumor efficacy than rHSV1/∆ICP6, albeit no statistical significance in inhibition of tumor volume. Histopathologically, rHSV1/∆RR induced massive neutrophil infiltration to the tumor microenvironment and consistently, triggered more antitumor immune and neutrophil chemotactic cytokines or higher expression levels of them (indicated by quantitative polymerase chain reaction and transcriptome analyses). These results demonstrate the anti-adenocarcinoma potential of the CRISPR/Cas9-engineered ICP6 mutant HSV1, especially the rHSV1/∆RR, which likely induces stronger innate antitumor immune response. Together, these findings may provide new valuable clues for further development of OV-based therapeutics against lung adenocarcinoma or other types of tumors.
溶瘤病毒（OVs），包括溶瘤单纯疱疹病毒（oHSVs），是治疗癌症的有前途的疗法。在这里，我们报告了两种通过 CRISPR/Cas9 生成的 ICP6 突变的 HSV（I 型），rHSV1/∆RR（ICP6 核糖核苷酸还原酶[RR] 结构域缺失）和 rHSV1/∆ICP6（ICP6 完全缺失），对肺腺癌表现出强大的抗肿瘤疗效。这两种突变体在体外均表现出强烈的细胞毒性，与表达完整 ICP6 的对照病毒相当，但滴度较低。此外，这些突变体病毒对肺肿瘤细胞表现出优先的杀伤能力，而对正常肺成纤维细胞则没有。此外，与导致小鼠模型中严重疾病或死亡的对照 HSV-1 不同，ICP6 突变病毒不会引起明显的致病性，而是在体内有效降低肿瘤负担，并导致动物 100%存活，表明具有显著的抗肿瘤活性和减弱的毒力。此外，rHSV1/∆RR 似乎比 rHSV1/∆ICP6 具有更好的抗肿瘤疗效，尽管在抑制肿瘤体积方面没有统计学意义。组织病理学检查显示，rHSV1/∆RR 诱导大量中性粒细胞浸润到肿瘤微环境中，并一致地引发更强的抗肿瘤免疫和中性粒细胞趋化细胞因子或更高的表达水平（通过定量聚合酶链反应和转录组分析）。这些结果表明，CRISPR/Cas9 工程改造的 ICP6 突变 HSV1 具有抗腺癌的潜力，特别是 rHSV1/∆RR，可能会引发更强的先天抗肿瘤免疫反应。总之，这些发现可能为进一步开发基于 OV 的治疗肺腺癌或其他类型肿瘤的疗法提供新的有价值线索。
