Qian Cao,1,* Ruijie Zhou,2,* Songlin Guo,3 Kai Meng,4 Xiaojuan Yang,5 Miao Liu,1 Bin Ma,6 Chunxia Su,5 Xiangguo Duan2 

1The First School of Clinical Medicine, Ningxia Medical University, Yinchuan, 750004, People’s Republic of China; 2School of Inspection, Ningxia Medical University, Yinchuan, 750004, People’s Republic of China; 3Institute of Medical Sciences, General Hospital of Ningxia Medical University, Yinchuan, Yinchuan, 750004, People’s Republic of China; 4Traditional Chinese Medicine Hospital of Ningxia Medical University, Yinchuan, 750003, People’s Republic of China; 5School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, 750004, People’s Republic of China; 6Department of Oncology Surgery, the First People’s Hospital of Yinchuan, Yinchuan, 750004, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Chunxia Su, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, 750004, People’s Republic of China, Email 1651085195@qq.com Xiangguo Duan, School of Inspection, Ningxia Medical University, Yinchuan, 750004, People’s Republic of China, Email 2455281549@qq.com

Background: Tumor vaccines have achieved remarkable progress in treating patients with various tumors in clinical studies. Nevertheless, extensive research has also revealed that tumor vaccines are not up to expectations for the treatment of solid tumors due to their low immunogenicity. Therefore, there is an urgent need to design a tumor vaccine that can stimulate a broad anti-tumor immune response.
Methods: In this work, we developed a nanovaccine (NP-TCL@APS), which includes nanoparticles loaded with colorectal cancer tumor cell lysates (TCL) and Astragalus polysaccharides (APS) into poly (lactic-co-glycolic acid) to induce a robust innate immune response. The NP-TCL@APS was identified by transmission electron microscopy and Malvern laser particle size analyzer. The killing and immune activation effects of NP-TCL@APS were evaluated in vitro. Finally, safety and anti-tumor efficacy were evaluated in the colorectal cancer tumor-bearing mouse model.
Results: We found that NP-TCL@APS was preferentially uptaken by DC and further promoted the activation of DC in vitro. Additionally, nanoparticles codelivery of TCL and APS enhanced the antigen-specific CD8+ T cell response and suppressed the growth of tumors in mouse models with good biocompatibility.
Conclusion: We successfully prepared a nanovaccine termed NP-TCL@APS, which can promote the maturation of DC and induce strong responses by T lymphocytes to exert anti-tumor effects. The strategy proposed here is promising for generating a tumor vaccine and can be extended to various types of cancers.

Keywords: colorectal cancer, nanovaccine, PLGA, Astragalus polysaccharide, tumor cell lysates (TCL)