Search

Nowadays, immunotherapy, in particular immunotherapeutic vaccines, is a promising approach in the treatment of cancer which has already demonstrated its effectiveness. Extracellular vesicles (EVs), which are capable of delivering biologically active agents to the cells, can be a promising candidate for such vaccines. M14 human melanoma cells were transduced with lentivirus encoding interleukin (IL)–2. Membrane vesicles from M14 cells expressing IL-2 were isolated using cytochalasin B. The interaction of membrane vesicles with human peripheral blood mononuclear cells has been analyzed. Activation of T cells was shown, as well as a decrease in the number of NK cells, after cultivation with tumor-derived vesicles. However, no cytotoxic activity of T cells after cultivation with tumor-derived vesicles was observed, which can be explained by their immunosuppressive properties. On the other hand, such vesicles can be a promising source of tumor-specific antigens for dendritic vaccines. Therefore, further studies are required in view of the possible use of tumor-derived vesicles as a target antigen for dendritic cells.

The development of imaging techniques in the experimental oncology has made it possible to model and continuously monitor growth and development of tumors in vivo. For this purpose, fluorescent or bioluminescent proteins are most commonly introduced into the genome of target cells which in turn can be used to create xenograft tumor models. In our study, SH-SY5Y human neuroblastoma cells were genetically modified with a firefly luciferase ffLucgene or far-red fluorescent protein Katushka2Sgene, and bioluminescence and fluorescence of obtained cells were analyzed in vitro. Then, produced cell lines were used to create xenograft tumor models in vivo.The bioluminescence and fluorescence of the obtained tumor models were evaluated in vivo.When evaluated in vitro, ffLuc bioluminescence was firstly detected within fewer number of SH-SY5Y cells compared to Katushka2S fluorescence. However, after in vivo administration, the fluorescence intensity of SH-SY5Y-Katushka2S cells was significantly higher than the bioluminescence intensity of the same number of SH-SY5Y-ffLuc cells. This may be due to the distribution and limited intracellular availability of a luciferase substrate, which is administered intraperitoneally, and requires further analysis.

At present, there is an increasing interest in the potential role of extracellular vesicles (EVs), acting as multi-signal messengers of the tumor stroma, in the development and progression of tumor. Tumor cell-derived EVs are considered a potential vector for the targeted delivery of antitumor agents due to the ability to fuse with parental cells through endocytosis and release their contents into the cytoplasm of the recipient cell. Tumor cell-derived EVs could be also used for priming immune cells and therapeutic vaccine development. It is also known that mesenchymal stem cells (MSCs) have a tropism toward tumor niches. It is believed that MSC migration to the tumor is due to its inflammatory signaling. Presumably, with the accumulation of MSCs at tumor sites, these cells differentiate into pericytes or tumor-associated fibroblasts, thereby forming a supporting tumor growth microenvironment. However, besides the ability to promote tumor progression, MSCs can also suppress its growth by inhibiting proliferation and cell cycle progression, and angiogenesis. Thus, the further studies of the MSC role in TME and MSC interaction with other cells of the tumor stroma, including through EVs, are of particular interest. To increase the yield of vesicles the isolation method based on pharmacological disorganization of the actin cytoskeleton induced by treating with cytochalasin B was used in this study. In this investigation the interaction of SH-SY5Y neuroblastoma cell-derived membrane vesicles, obtained using cytochalasin B (CIMVs), with human bone marrow-derived MSCs was analyzed using imaging flow cytometry. Using transmission electron microscopy, it was shown that CIMVs have a size similar to that of natural microvesicles, which is 100–1000 nm. Using imaging flow cytometry, it was shown that after 24 h of co-cultivation 6% of the MSCs contained a large number of CIMVs, and 42% of the MSCs contained a small amount of CIMVs. Cultivation of MSCs with SH-SY5Y cell-derived CIMVs also induced dose-dependent decrease in the expression of CD markers typical for MSCs. Thus, the internalization of SH-SY5Y cell-derived CIMVs within MSCs and the ability of the CIMVs to modulate immunophenotype of the recipient cells were shown. However, further studies are required to determine the effect of CIMVs on pro- or antioncogenic phenotype and function of MSCs.