PO.IM01.05 · 免疫学
适形外照射放疗在胰腺癌肝转移小鼠模型中增加B7-H3表达并促进CAR-T细胞功能
Conformal external beam radiation increases B7-H3 expression in a murine model of pancreatic cancer liver metastases and promotes CAR T cell function
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：胰腺导管腺癌（PDAC）是一种以早期肝转移为特征的致命疾病。嵌合抗原受体（CAR）修饰细胞（T和NK细胞）在PDAC和其他实体瘤中大多未获成功，尽管其在血液系统恶性肿瘤中取得了成功。CAR疗法在实体瘤中取得成功的限制因素包括迁移、植入和抗原丢失。肝脏定向放疗（RT）可能通过改变肿瘤和肿瘤微环境来改善CAR疗法。我们在PDAC肝转移的异种模型中研究了肝脏定向放疗（RT）增强B7-H3 CAR-T细胞归巢和功能的作用。
方法：我们在体外和体内通过流式细胞术评估了RT后人PANC-1和AsPC-1细胞中B7-H3和NKG2D活化配体的剂量依赖性表达，包括使用半脾植入技术接种肝脏的单纯肝转移模型。生成B7-H3 CAR-T细胞并通过流式细胞术进行评估。随后将B7-H3 CAR-T细胞与经RT处理的靶细胞共培养，并使用Incucyte活细胞成像分析细胞毒性。
结果：体外RT后，PANC-1和AsPC-1细胞的B7-H3和NKG2D配体MICA/B表达，无论以中位荧光强度还是表达百分比衡量，均显著增加。与未治疗的小鼠相比，肝脏定向RT导致PANC-1肝转移灶上B7-H3和MICA/B的表达显著增加。当靶细胞在杀伤实验前预先接受4 Gy RT处理时，B7-H3 CAR-T细胞对PANC-1和AsPC-1细胞的杀伤百分比显著增加。
结论：RT增加了胰腺癌细胞系上B7-H3以及NKG2D配体MICA/MICB的表达，这在对荷转移小鼠进行肝脏定向RT后于体内得到重现。用RT预处理靶细胞可使体外B7-H3 CAR-T细胞杀伤增强。肝脏定向RT可能是一种利用CAR细胞疗法更好地靶向PDAC肝转移的策略。
查看英文原文 English abstract
Background: Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease characterized by early liver metastases. Chimeric antigen receptor (CAR) modified cells (T and NK) have been largely unsuccessful in PDAC and other solid tumors, despite success in hematologic malignancies. Limitations to CAR therapy success in solid tumors include trafficking, engraftment, and antigen loss. Liver-directed radiation (RT) may improve CAR therapy through altering the tumor and tumor microenvironment. We investigated the impact of liver-directed radiation therapy (RT) to augment B7-H3 CAR T cell homing and function in a xenogeneic model of PDAC liver metastases.
Methods: We evaluated dose-dependent expression of B7-H3 and NKG2D activating ligands by flow cytometry in human PANC-1 and AsPC-1 cells in vitro and in vivo after RT, including a liver-only metastatic model using a hemi-spleen implantation technique to seed the liver. B7-H3 CAR T cells were generated and assessed by flow cytometry. B7-H3 CAR T cells were then co-cultured with RT-treated target cells, and cytotoxicity was analyzed using Incucyte live cell imaging.
Results: Following RT in vitro , PANC-1 and AsPC-1 cells exhibited significant increase in expression of both B7-H3 and NKG2D ligands MICA/B by either median fluorescent intensity or percent expression. Liver-directed RT led to significantly increased expression of B7-H3 and MICA/B on PANC-1 liver metastases compared to untreated mice. Percent killing by B7-H3 CAR T cells against PANC-1 and AsPC-1 cells was significantly increased when target cells were pre-treated with 4 Gy RT prior to killing assay.
Conclusions: RT increases the expression of both B7-H3 and the NKG2D ligands MICA/MICB on pancreas cancer cell lines and this is recapitulated in vivo following liver-directed RT to metastasis-bearing mice. Pre-treating target cells with RT results in greater B7-H3 CAR T cell killing in vitro . Liver-directed RT may be a strategy to better target PDAC liver metastases with CAR cell therapy.
利益披露 Disclosure
M. C. Purl, None..
A. Shick, None..
A. Grimm, None..
H. Abdallat, None..
C. J. Sholevar, None..
M. Karimzadeh, None..
N. M. Liu, None..
J. Kim, None..
C. E. Gaskill, None..
E. J. Kim, None..
A. M. Monjazeb, None..
W. J. Murphy, None..
R. J. Canter, None..
S. J. Judge, None.