This study aims to investigate the potential of oncolytic nanoparticles encapsulating Coxsackievirus A21 (CVA21) full-genome mRNA (CVA21@ONP) to resurrect CVA21 and induce apoptosis in host cells, as well as the antitumor immune effects of CVA21@ONP in immunocompetent tumor-bearing BALB/c mice. We used lipid nanoparticles (LNPs) to encapsulate CVA21 full-genome mRNA, thus preparing CVA21@ONP. The killing efficacy of CVA21@ONP was determined by the plaque assay and cell counting kit-8 (CCK-8), and the apoptosis in HT29 and CT26-iRFP cells was evaluated by flow cytometry. Mice were administrated with CVA21@ONP at high and low doses intratumorally, and the growth of tumors expressing infra-red fluorescent protein (iRFP) was monitored. Additionally, the types and changes of immune cells in the spleen were analyzed by flow cytometry. The results demonstrated that CVA21@ONP successfully resurrected CVA21 in both HT29 and U87MG cells. The plaque assay revealed robust killing effects of CVA21@ONP against both human and murine cell lines, and flow cytometry results showed increased early and late apoptotic cells. Notably, intratumoral detection revealed significantly down-regulated expression of iRFP in both high- and low-dose CVA21@ONP groups. Flow cytometry results further indicated that CVA21@ONP treatment effectively reduced the levels of immunosuppressive cells, including myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), in the spleen, while enhancing T cell-dependent antitumor immune responses. These findings suggest that CVA21@ONP can replicate and survive extensively both in vitro and in vivo, activating the immune system of mice administrated with CVA21@ONP to target cells at the tumor site, thereby remodeling the tumor immune microenvironment and accelerating the suppression or even complete regression of tumors. The oncolytic performance of CVA21@ONP has been verified through intratumoral injection administration in this study, aimed at further exploring its therapeutic potential and promoting the development of the field of tumor treatment.
Animals ; Nanoparticles/chemistry* ; Mice ; Mice, Inbred BALB C ; Humans ; Apoptosis ; Oncolytic Viruses/genetics* ; Oncolytic Virotherapy/methods* ; Cell Line, Tumor ; RNA, Messenger/genetics* ; HT29 Cells

Objective:Detect the gut microbiota change in mice caused by 10 ％ short-chain inulin addition in high fat diet condition.Methods:8-week-old male C57/B6J mice,5 mice were fed with high fat diets,5 mice were fed with high fat diets with 10 ％ short-chain inulin addition.Fed 8 weeks and then collected fresh feces.Detected the three main short chain fatty acids in fresh feces.Extracted gut bacteria genome DNA for 16S rRNA V4 region sequencing.Principal Coordinate Analysis (PCoA),Alpha diversity and LEfSe analysis were performed to detect gut microbiota changes induced by short chain inulin.Results:Gut bacterial DNA amount and SCFAs amount per gram feces increased.PCoA analysis demonstrated fecal microbiota from inulin and control group mice had distinctive different features and clustered well.Inulin group owned lower fecal microbiota diversity compared with control group.LEfSe analysis revealed that in family level,Ｓ24_7 increased,Deferribacteraceae,Lachnospiraceae and Ruminococcaceae decreased.PICRUSt predicted that 22 level 2 KEGG Orthology groups changed.Conclusions:Inulin addition altered the gut microbiota composition in mice in high fat diet condition and impact the gut microbiota gene function.