Moeinzadeh Leila, Ramezani Amin, Mehdipour Fereshteh, Yazdanpanah-Samani Mahsa, Razmkhah Mahboobeh
Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran.
Shiraz Institute for Cancer Research, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Biomed Res Int. 2023 Jun 7;2023:7692726. doi: 10.1155/2023/7692726. eCollection 2023.
Due to their ability to recruit immune cells to kill tumor cells directly, bispecific T cell engager antibodies (BiTE) hold great potential in T cell redirecting therapies. BiTE is able to activate T cells through CD3 and target them to tumor-expressed antigens. However, there are many components in the tumor microenvironment (TME) such as mesenchymal stem cells (MSCs) that may interfere with BiTE function. Herein, we designed an anti-PDL1-BiTE that targets programmed death ligand 1 (PDL1) and CD3 and investigated its effect on PDL1pos cancer cells in the presence or absence of adipose-derived MSCs (ASCs).
Our anti-PDL1-BiTE comprises of VL and VH chains of anti-CD3 monoclonal antibody (mAb) linked to the VL and VH chains of anti-PDL1 mAb, which simultaneously bind to the CD3 subunit on T cells and PDL1 on tumor cells. Flow cytometry was employed to assess the strength of binding of anti-PDL1-BiTE to tumor cells and T cells. Cytotoxicity, proliferation, and activation of peripheral blood lymphocyte (PBLs) were evaluated by CFSE assay and flow cytometry after using anti-PDL1-BiTE in the presence or absence of ASCs and their conditioned media (C.M.).
Anti-PDL1-BiTE had the ability to induce selective lysis of PDL1pos U251-MG cancer cells while PDL1neg cells were not affected. Also, anti-PDL1-BiTE significantly stimulated peripheral blood lymphocyte (PBL) proliferation and CD69 expression. ASCs/C.M. did not show a significant effect on the biological activity of anti-PDL1-BiTE.
Overall, anti-PDL1-BiTE selectively depletes PDL1pos cells and represents a new immunotherapeutic approach. It would increase the accumulation of T cells and can improve the prognosis of PDL1pos cancers in spite of the immunomodulatory effects of ASCs and C.M.
双特异性T细胞衔接抗体（BiTE）因其能够募集免疫细胞直接杀伤肿瘤细胞，在T细胞重定向治疗中具有巨大潜力。BiTE能够通过CD3激活T细胞，并使其靶向肿瘤表达的抗原。然而，肿瘤微环境（TME）中有许多成分，如间充质干细胞（MSCs），可能会干扰BiTE的功能。在此，我们设计了一种靶向程序性死亡配体1（PDL1）和CD3的抗PDL1-BiTE，并研究了在存在或不存在脂肪来源的间充质干细胞（ASCs）的情况下，其对PDL1阳性癌细胞的作用。
我们的抗PDL1-BiTE由抗CD3单克隆抗体（mAb）的VL和VH链与抗PDL1 mAb的VL和VH链连接而成，可同时结合T细胞上的CD3亚基和肿瘤细胞上的PDL1。采用流式细胞术评估抗PDL1-BiTE与肿瘤细胞和T细胞的结合强度。在存在或不存在ASCs及其条件培养基（C.M.）的情况下使用抗PDL1-BiTE后，通过CFSE检测和流式细胞术评估外周血淋巴细胞（PBLs）的细胞毒性、增殖和活化情况。
抗PDL1-BiTE能够诱导PDL1阳性的U251-MG癌细胞发生选择性裂解，而PDL1阴性细胞不受影响。此外，抗PDL1-BiTE显著刺激外周血淋巴细胞（PBL）增殖和CD69表达。ASCs/C.M. 对抗PDL1-BiTE的生物学活性没有显著影响。
总体而言，抗PDL1-BiTE可选择性清除PDL1阳性细胞，代表了一种新的免疫治疗方法。尽管ASCs和C.M. 具有免疫调节作用，但它会增加T细胞的聚集，并可改善PDL1阳性癌症的预后。
