PO.IM01.12 · 免疫学
溶瘤病毒在使用同基因和PDX模型的三阴性乳腺癌中展现出强大的抗肿瘤和免疫调节作用
Oncolytic virus exhibits potent antitumor and immunomodulatory effects in triple-negative breast cancer using syngeneic and PDX models
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
三阴性乳腺癌（TNBC）占乳腺癌的15-20%，其特征是快速增殖和致癌通路激活，为溶瘤病毒复制创造了有利环境。JX-594（pexastimogene devacirepvec）是一种基因工程改造的痘苗病毒，其中胸苷激酶基因被人GM-CSF替换，从而实现选择性肿瘤复制和免疫激活。我们的体外研究证明TNBC细胞系对JX-594高度敏感。基于这些发现，我们建立了TNBC同基因和患者来源异种移植（PDX）模型，以研究JX-594诱导的肿瘤微环境内分子和免疫学变化。同基因模型通过将4T1和EMT6细胞植入BALB/c小鼠的乳腺脂肪垫中生成。当肿瘤达到约30-60 mm³时，小鼠接受瘤内mJX-594注射（5 × 10⁷ PFU，每三天一次共三剂）。第10天，收取肿瘤进行组织病理学和免疫组化（IHC）分析。为进行转化验证，从人乳腺癌组织建立了TNBC PDX模型。当肿瘤达到约30 mm³时，小鼠接受瘤内注射JX-594（1 × 10⁷ PFU），每周一次共四周。28天后，通过IHC检测肿瘤样本的Ki-67、CD31和痘苗抗原。在两种模型中，整个治疗期间均监测肿瘤生长和体重。在同基因TNBC模型中，与对照相比，mJX-594治疗显著抑制了肿瘤生长，并伴随CD4⁺和CD8⁺ T淋巴细胞浸润增加，以及CD31染色所示的微血管密度降低。相比之下，PD-1/PD-L1和CD20表达水平未发生显著改变。在TNBC PDX模型中，首次JX-594给药后观察到肿瘤体积初始短暂增大，随后在第二次治疗后出现明显的肿瘤消退和持续的生长抑制。IHC分析显示广泛的肿瘤坏死、Ki-67和CD31表达降低以及痘苗抗原染色阳性，表明肿瘤微环境内活跃的病毒复制和持续的溶瘤作用。本研究证明，JX-594通过免疫激活、抗血管生成作用和直接溶瘤机制在TNBC中发挥强大的抗肿瘤活性。在同基因和PDX模型中观察到的一致治疗疗效凸显了JX-594的转化意义。尽管若干研究已探索了针对TNBC的基于溶瘤病毒的疗法，但使用PDX模型的临床前验证仍极为有限。我们的发现提供了支持JX-594治疗潜力的有力体内证据，并为推进TNBC溶瘤病毒疗法奠定了转化基础。
查看英文原文 English abstract
Triple-negative breast cancer (TNBC), which accounts for 15-20% of breast cancers, is characterized by rapid proliferation and oncogenic pathway activation, creating a permissive environment for oncolytic virus replication. JX-594 (pexastimogene devacirepvec) is a genetically engineered vaccinia virus in which the thymidine kinase gene is replaced with human GM-CSF, enabling selective tumor replication and immune activation. Our in vitro studies demonstrated high sensitivity of TNBC cell lines to JX-594. Based on these findings, we established TNBC syngeneic and patient-derived xenograft (PDX) models to investigate JX-594-induced molecular and immunologic changes within the tumor microenvironment. Syngeneic models were generated by implanting 4T1 and EMT6 cells into the mammary fat pads of BALB/c mice. When tumors reached approximately 30-60 mm³, mice received intratumoral mJX-594 injections (5 × 10⁷ PFU, three doses every three days). On day 10, tumors were harvested for histopathologic and immunohistochemical (IHC) analyses. For translational validation, TNBC PDX models were established from human breast cancer tissues. When tumors reached approximately 30 mm³, mice received intratumoral injections of JX-594 (1 × 10⁷ PFU) once weekly for four weeks. After 28 days, tumor samples were examined by IHC for Ki-67, CD31, and vaccinia antigen. Tumor growth and body weight were monitored throughout the treatment period in both models.In syngeneic TNBC models, mJX-594 treatment markedly suppressed tumor growth compared with controls and was associated with increased infiltration of CD4⁺ and CD8⁺ T lymphocytes, as well as reduced micro-vessel density as indicated by CD31 staining. In contrast, PD-1/PD-L1 and CD20 expression levels were not significantly altered. In TNBC PDX models, an initial transient increase in tumor size was observed following the first JX-594 administration, followed by pronounced tumor regression and sustained growth suppression after the second treatment. IHC analyses revealed extensive tumor necrosis, decreased Ki-67 and CD31 expression, and positive vaccinia antigen staining, indicating active viral replication and ongoing oncolysis within the tumor microenvironment.This study demonstrates that JX-594 exerts potent anti-tumor activity in TNBC through immune activation, anti-angiogenic effects, and direct oncolytic mechanisms. The consistent therapeutic efficacy observed in both syngeneic and PDX models highlights the translational significance of JX-594. Although several studies have explored oncolytic virus-based therapies for TNBC, preclinical validation using PDX models remains extremely limited. Our findings provide robust in vivo evidence supporting the therapeutic potential of JX-594 and establish a translational foundation for advancing
oncolytic virotherapy in TNBC.
利益披露 Disclosure
Y. Kim, None..
J. Lee, None.