Construction And Anti-tumor Effect Of Recombinant Oncolytic Adenovirus Expressing MARCO

With the advancement of genetic engineering technology,modified oncolytic viruses have become widely used in malignant tumor treatment.Oncolytic adenoviruses have been demonstrated in clinical trials to be safe.It can be selectivity to replicate in tumor tissue,lyse tumor cells effectively,and induce tumor inflammation and anti-tumor immune response.Furthermore,oncolytic adenovirus is well suitable for specific foreign genes which can be used to more effectively utilize and amplify the immune effect.In a brief,oncolytic adenovirus is a wonderful tool for cancer immunotherapy.MARCO,a scavenger receptor with a collagen domain on macrophages,is expressed on particular macrophage subpopulations like lymph nodes,liver,and spleen.It is a member of class A of the scavenger receptor family.MARCO has various recognition ligands in common with PRRs,including exogenous Gram-negative bacteria and Gram-positive bacteria cell walls,endogenous Ox-LDL and Ac-LDL,apoptotic cells,tumor cells,etc.These suggest that MARCO is involved in mediates the binding and uptake of pathogens and tumor.The majority of studies on MARCO in diseases focus on Alzheimer’s disease,atherosclerosis,and other diseases.Nevertheless,little is known about the role of MARCO in the growth of tumors,and it is still unclear how the immune system of tumor cells expressing MARCO receptors is regulated.In light of the aforementioned issues,the major goal of this work is to develop,on the basis of prior research,a recombinant oncolytic adenovirus that expresses the murine MARCO gene and investigate its anti-tumor activity and immunoregulatory impact in the tumor microenvironment.The murine MARCO gene was first inserted into the oncolytic adenovirus(CRAd)-related expression vector by homologous recombination to create the p DC316-m MARCO-GFP-dl24E1 shuttle vector.Next,the adenovirus type 5(Ad5)backbone plasmid packaging CRAd5-m MARCO recombinant oncolytic adenovirus was combined.CRAd5-m MARCO was found to be effective against various tumor cell lines,including Lewis,Hepa1-6,CT26,and 4T1,but there was no obvious killing effect on normal mouse 3T6 cells,suggesting good safety.The cell scratch experiment followed,which demonstrated that CRAd5-m MARCO has the ability to inhibit cell migration.Next,we used flow cytometry to examine the recombinant virus’s impact on tumor cell apoptosis,and the results revealed that CRAd5-m MARCO could significantly increase the apoptosis of Lewis and Hepa1-6 cells.After that,we used q RT-PCR to evaluate the recombinant virus’s ability to stimulate the immune system in vitro.We found that in the model,CRAd5-m MARCO can significantly increase the expression levels of cytokines that are related to anti-tumors,including TNF-α,IL-6,IL-18,IL-23 and CXL10.These results suggest that CRAd5-m MARCO can be used in the treatment of tumors such as lung and liver cancer.Ultimately,the anti-tumor effects of CRAd5-m MARCO as well as the mechanisms of immune modulation were further investigated through the development of Lewis immune totipotent mice model.The outcomes shown that intratumoral injection of CRAd5-m MARCO effectively suppressed tumor growth as compared to the control group.According to flow cytometry analysis of the intratumoral immune cell composition,therapy with CRAd5-m MARCO can considerably boost lymphocyte infiltration,decrease the amount of intratumoral suppressor cells,and enhance CD4~+T cell and CD8~+T cell activation.The effect of CRAd5-m MARCO in preventing tumor metastasis in vivo will be further examined in the future.We will also thoroughly examine the anti-tumor mechanism and safety of oncolytic adenoviruses expressing m MARCO.The research presented in this paper serves as a foundation for additional research on the anti-tumor immune control of MARCO and the use of oncolytic adenovirus.