The Application And Mechanism Of Ultrasound-mediated Physical Injury Technology To Activate The Body's Immunity In Tumor Treatment

Background:With the gradual and in-depth discussion of immunology and tumor pathogenesis,tumor immunotherapy has become one of the most anticipated research fields.As one of the important components of immunotherapy,tumor vaccines have grown rapidly in recent years and have obtained many excellent results in the fields of basic research and clinical research.This study uses tumor cell lysates(TCL)combined with adjuvant to prepare tumor vaccine,and intends to explore its potential immune activation and tumor suppression effects in melanoma,and to pave the way for follow-up research.Materials and Methods:We used an ultrasonic disruptor to prepare B16F10 melanoma TCL and used trypan blue staining to confirm its activity.Twenty-four C57BL/6 mice were randomly divided into four groups.PBS,IL-2,TCL and TCL+IL-2 were injected subcutaneously respectively,once a week for 3 weeks.In the 4th week,the contralateral tumor was implanted,and the tumor emergence time and tumor size were observed.The peripheral blood of mice was continuously collected for CD4+T and CD8+T flow dynamic analysis.The expression of CD4+T and CD8+T in the spleen and tumor tissues were also detected by flow cytometry and immunohistochemistry.Results:The tumor emergence time was significantly delayed after prophylactic immunization in the TCL+IL-2 group(p=0.034),and the tumor volume(p=0.023)and tumor weight(p=0.0015)were also significantly smaller than those in the control group.The results of flow cytometry showed that the proportion of CD8+T cells in the peripheral blood of the TCL+IL-2 group and the TCL group alone was significantly higher than that of the control group(p=0.0016,p=0.012).The CD4+T cells in the TCL+IL-2 group decreased after tumor implantation compared with the control group(p=0.0089).The proportions of CD4+T and CD8+T cells in the spleen and tumor tissues were the same as the expression trends in peripheral blood.Conclusions:TCL combined with IL-2 can effectively activate the body's immunity,prevent the occurrence of melanoma in mice and inhibit the growth of tumors.Backgrounds:With the rapid development of material technology and medical imaging technology,new physical therapy methods have become another important strategy for tumor treatment in recent years.Ultrasound microbubble physical therapy technology is a non-invasive physical therapy method.Phase change nanoparticles undergo a liquid-to-gas phase change under the intervention of external ultrasound,which leads to cell injury in situ.This study intends to investigate the role of a physical therapy consisited of ultrasound combined and phase-change nanoparticles in breast cancer and the related immune activation mechanisms.Materials and Methods:Preparing lipid fluorocarbon nanoparticles(LIP-PFH nanoparticles),use Malvern particle size and potential detection equipment to test their physical and chemical properties,and use confocal methods to determine the phagocytosis of 4T1 breast cancer cells.Through CCK-8 experiment,apoptosis and cycle experiment,the anti-tumor effect of low-frequency ultrasound combined with nano-particle physical therapy technology in vitro is analyzed.The establishment of Balb/c breast cancer mouse xenograft model to further confirm the anti-tumor effect of the physical therapy,and through the HE staining of lung metastases,preliminary suggestion of the effect on distant metastasis.Flow cytometry was used to monitor the changes of CD4+T,CD8+T cells in peripheral blood,spleen and tumor tissues of mice.Detection of immunogenic cell death markers to study the underlying immune mechanism,and use nude mice to confirm again.Results:Low-intensity focused ultrasound combined with LIP-PFH nanoparticles can effectively inhibit the proliferation of 4T1 cells and promote their apoptosis both in vitro and in vivo.An inhibitory effect on distant metastasis also have been preliminarily showed in vivo animal experiments.The proportion of CD4+T and CD8+T cell subsets in peripheral blood,spleen and tumor tissues increased significantly,indicating that this physical therapy technique effectively increases the anti-tumor immune response of breast cancer cells.Flow cytometric analysis of immunogenic cell death markers(ATP,high mobility group box B1 and calreticulin)and DC cell maturity showed that the physical therapy technology can induce immunogenic cell death in 4T1 breast cancer cells and mediates DC maturation to increase the proportion of cytotoxic T cells.Nude mouse experiments further verified this mechanism.Conclusion:The new physical therapy combined with ultrasound and nanoparticles can effectively enhance the anti-tumor immunity of breast cancer cells and improve their immunogenicity,providing potential research directions for improving the efficacy of breast cancer immunotherapy in the future.