Study On TIGIT/CD40 Cell Membrane Nanovesicles Coated With Melanin-Oxaliplation In The Treatment Of Pancreatic Cancer

Objective:As a novel drug delivery material,cell vesicles have been proved to have good biocompatibility and certain biological targeting.The purpose of this study was to investigate whether the TIGIT/CD40 overexpressed nanovesicles carrying melanin-oxaliplatin(OXA)could inhibit the growth of tumor cells by inhibiting the TIGIT/CD155 immune checkpoint in the mouse pancreatic cancer model,and target the release of the drugs contained in them to the tumor site to achieve the tumor killing effect.Methods:1.Stable cell lines overexpressing TIGIT/CD40 were constructed by lentivirus packaging.Cell vesicles derived from biological cell membranes were prepared by differential centrifugal method.At the same time,they were coated with MO@Ti40 NVs by electrorevolution.2.The characterization of TIGIT/CD40 cell vesicles and the expression of TIGIT/CD40 protein were identified by Western Blot and transmission electron microscopy,as well as the size distribution of the vesicles and melanin detected by dynamic scattering light.3.Observe the combination of TIGIT/CD40 expressed cell vesicles with pancreatic cancer cells,and verify the role of MO@Ti40 NVs in promoting pancreatic cancer apoptosis and inhibiting tumor cell growth in vitro.4.Construct C57BL/6J mouse pancreatic cancer model to verify the effect of MO@Ti40NVs on animal pancreatic cancer model.Immunohistochemical and HE staining and flow cytometry were used to observe the effects of MO@Ti40 nanoparticles on T cell immunity and inflammation in vivo.Results:1.Cell vesicles with high TIGIT/CD40 expression were prepared from TIGIT/CD40 stable overexpression HEK293 T cell lines,and then MO@Ti40 NVs were prepared by electrotransfer by embedding melanin-oxaliplatin.2.TIGIT/CD40 cell vesicles can bind specifically to CD155/CD40 L on the surface of pancreatic cancer cells.3.Melanin-oxaliplatin can inhibit the growth of pancreatic cancer cells in vitro.4.MO@Ti40 NVs promoted apoptosis and inhibited proliferation of pancreatic cancer cells in vitro.5.MO@Ti40 NVs significantly inhibited the growth of pancreatic cancer in C57BL/6J mouse pancreatic cancer models.Conclusion:In this study,melanin-oxaliplatin and TIGIT/CD40 were used to inhibit immune escape in nanovesicles,thereby achieving tumor growth inhibition.As a very good biocompatible carrier,nanovesicles can effectively carry cytotoxic drugs to achieve the purpose of targeted treatment of tumors,providing a treatment plan for clinical treatment of pancreatic cancer that can be further explored and transformed.