The Nano-based Immunotherapy And Chemotherapy For The Treatment Of An Advanced Melanoma

Objectives. Tumor immunotherapy is the use of immune ways to provoke the immune systems for the tumor specific killing, which is the hotspot for tumor treatment in recent years. But the response rate of tumor immunotherapy is extremely low, especially for the treatment of the late-stage malignant melanoma. It is a common sence universally acknowledged, that certain molecules(such as tumor antigen peptides, oligonucleotides etc.) encapsulated in the nanoparticles are able to prime immune reactions. Furthermore, the nano-vaccine or nano-adjuvant exhibit enhanced immune responses, while combining with the chemo-drugs. The combination therapy is able to lower the levels of immunesuppressive factors in the tumor microenvironment, enhancing immune response as well as effectively inhibiting the growth of malignant melanoma. There are two possible ways of combining immunotherapy and chemotherapy against the advanced melanoma. One of the combination therapies is suitable for the model that tumor antigens can be easily found; the other one is suitable for the tumor model that is difficult to find certain tumor antigens.Methods. For the first model, the amphiphilic pro-drug of curcumin were synthesized and dissolved in water for the formation of self-assembled micelles Cur PM. Then, in the B16F10 tumor-bearing mice, the anti-tumor efficacy of the combined therapy was compared with both of the two individual treatments and the control group. Subsequently, in vivo CTL response, interferon-gamma(IFN-γ) production and the key signaling pathways were monitored. Then, the numbers of immunesupressive cells such as myeloid-derived suppressor cells(MDSC) and regulatory T cells(Treg), levels of cytokines in the local melanoma microenvironment were also detected. Finally, the bloody chemistry was also analyzed for the toxicity evaluation. For the second model, Lipid-coated cisplatin nanoparticles(LPC) and Cp Gencapsulated liposomes(Cp G-Lipo) were prepared for the temporally controlled and multifaceted treatments of an advanced melanoma tumor model. The tumor volumes, mean survival times, and organ toxicities were monitored. We also conducted the ELISPOT assay, flow cytometry assay and ELISA assay for the determination of IFN-γ production, the number of immune cells and levels of cytokines, respectively.Results. For the first model, the combination therapy significantly retarded the tumor growth compared with other groups. In the immune organs such as spleens, the combination therapy significantly boosted in vivo CTL response and ELISPOT production-IFN-γ. In the tumor microenvironment, Combining Cur PM and Trp-Vac dramatically down regulated the signal transducer and activator of transcription-3(STAT3) pathway, which is the common signal pathway. The combination therapy led to significantly down-regulated levels of immunosuppressive factors, such as decreased numbers of MDSC and Treg cells, declined levels of interleukin-6(IL-6) and chemokine ligand 2(CCL2); in correlation with elevated levels of proinflammatory cytokines, including tumor necrosis factor- alpha(TNF-α) and IFN-γ as well as an enhancement in the CD8+ T cell infiltration. For the second model, this kind of combination therapy established a strong synergistic effect on both of the apoptotic extent and subsequent abrogation of tumor growth, due largely to the enhanced cytotoxic T-cell recruitment and the reduction of immune-suppressive mediators in the microenvironments of both spleen and tumor tissue. So the toxcicity and lung metastasis were dramaticly reduced.Novelty.1 The drugs, the tumor vaccine and the adjuvant were all encapsulated in nanosystems. According to the different properties of the drugs, we designed different nano-delivery systems for the purpose of different organs targeting. 2 These nano-based drug delivery systems were able to accumulate in tumor microenvironment, which led to reduction of the immunosuppressive factors. When these drugs were combined with nano-vaccine or adjuvant, the specific cytotoxic T cells were facilitated to infiltrate to tumor tissues, thus effectively inhibiting the growth of melanoma. 3 We exploited two kinds of combination therapies based on the nano-delivery systems. Tumor vaccine combined with curcumin micelles was applied to retard the tumor growth that contains specific tumor antigens. While the tumors were lack of specific tumor antigens, LPC were used to induce self-antigens in situ. Subsequently, with the help of the adjuvant-Cp G-Lipo, antigen presentation process was dramaticly enhanced, which facilitated the priming of adaptive immune responses.