## 3 Results
### Immunotherapy
#### 3.5.1 Nanoparticle-Based Vaccines  
Nanoparticle-based vaccines represent a promising approach in the treatment of hepatocellular carcinoma, leveraging their ability to enhance immune responses and effectively target tumor cells. These vaccines utilize nanoparticles as delivery systems to protect antigens, enhance cellular uptake, and promote immune activation against tumor-specific antigens [84].  
Advances in mRNA technology have introduced nanoparticle-based mRNA vaccines as a versatile platform for liver cancer. These vaccines encode tumor antigens, ensuring their expression in targeted cells, and utilize LNPs to protect and deliver the mRNA effectively.  
In an innovative study, [PERSON] et al. investigated the use of lipid nanoparticles to deliver tumor-derived RNA as a therapeutic vaccine against hepatocellular carcinoma. This strategy aimed to stimulate dendritic cells (DCs), promoting their maturation and enhancing the activation of cytotoxic T lymphocytes (CTLs) capable of recognizing and eliminating tumor cells. The RNA was extracted from Hepa1-6 liver cancer cells and encapsulated into LNPs formulated with DOTAP and cholesterol to ensure both structural stability and efficient cellular uptake.  
A schematic overview of this immune activation process, highlighting the interplay between tumor antigens, immune cells, and checkpoint molecules, is illustrated in Figure 5[85].  
The RNA-LNP vaccine was tested both in vitro and in vivo, where it demonstrated strong immunostimulatory effects. Dendritic cells exposed to the vaccine showed enhanced maturation, while cytotoxic T lymphocyte activation was significantly improved. In mouse models, the treatment led to a marked reduction in tumor growth, confirming the vaccine's  
Figure 5: Schematic representation of tumor vaccine and immunotherapy strategy using lipid nanoparticles for RNA delivery. The image illustrates antigen presentation by dendritic cells, activation of helper and cytotoxic T cells, immune checkpoints, and mechanisms of immune evasion by tumor cells. Reproduced with permission from [PERSON] et al. [85].  
therapeutic potential. Altogether, the findings support RNA-loaded LNPs as a promising and well-tolerated platform for antigen-specific immunotherapy in liver cancer. However, the authors emphasized that tumor heterogeneity poses a challenge in identifying universally expressed tumor antigens, and although total RNA expands antigenic diversity, it does not guarantee immunogenicity or tumor specificity. Furthermore, systemic and local immunosuppression may reduce vaccine efficacy, particularly in patients with a compromised immune response [85].  
[PERSON] et al. explored a next-generation vaccine delivery strategy for hepatocellular carcinoma that enhances immune activation through targeted antigen transport. They designed spike-shaped silicon nanoparticles capable of co-delivering tumor-specific neoantigens and immune adjuvants directly into the cytoplasm of antigen-presenting cells. By leveraging caveolin-mediated uptake, this system improved antigen presentation and minimized degradation, thereby promoting the activation of cytotoxic CD8\({}^{+}\) T cells. The study demonstrated that this platform enhanced immune cell responses in vitro and led to significant tumor suppression and prolonged survival in mouse models. When used alongside checkpoint inhibitors, the therapeutic effect was even greater, suggesting a promising synergy with established immunotherapies. These results point to the potential of such nanoparticle systems to support personalized vaccination strategies for HCC. However, limitations of the study include the need to explore the durability of the immune response in long-term models, potential variability in antigen uptake across different tumor environments, and the requirement to optimize dosing and delivery strategies before clinical translation [86].