| Background Colon cancer peritoneal carcinomatosis is a hidden disease,and there is currently no effective treatment.Chimeric antibody receptor engineered T cell(CAR-T)is the latest adoptive cell reinfusion therapy technology,which can express specific receptors and target specific cells to induce tumor cell apoptosis.However,solid tumors have not yet matched good targets,and there are problems such as off-target effects,difficulty in homing effector cells,and serious systemic complications.Objective This study aimed to assess prognostic significance the expression of B7-H3 in peritoneal metastasis stage IV colorectal cancer and the feasibility of B7-H3 as a target antigen for tumor immune cell therapy,and builds a NCG mouse model of colorectal cancer peritoneal metastasis to evaluate B7-The inhibitory effect of H3CAR-T cells on tumors in animal models provides a strong experimental basis and experimental basis for future clinical transformation therapy of individualized chimeric antigen receptor T cell technology.Method 1.Use public database to analyze the difference of B7-H3 expression in various tumors.2.To analyze the correlation between B7-H3 and related genes and immune cell markers in colon cancer.3.Analyze the correlation between B7-H3 and immune checkpoint blocking molecules.4.To detect the correlation of B7-H3 in colon cancer with 22 tumor infiltrating immune cells.5.Use the public database to analyze the relationship between the expression of B7-H3 and prognosis in colon cancer and verify it.By combining clinical specimens of colon cancer with abdominal metastasis,use immunohistochemistry to analyze the expression and prognosis of B7-H3 at the protein level relationship.6.Western blot was used to detect the expression level of B7-H3 in different colon cancer tumor cells.Flow cytometry was used to analyze the specific killing of B7-H3 CAR-T cells in vitro by B7-H3 CAR-T cells.7.Build and identify an in situ PDX model of peritoneal metastasis of colon cancer,and evaluate the inhibitory effect of B7-H3 CAR-T on the in situ PDX model of peritoneal metastasis of colon cancer.Results 1.Compared with paracancerous controls,B7-H3 is highly expressed in gastrointestinal tumors such as cholangiocarcinoma(CHOL),colon cancer(COAD),esophageal cancer(ESCA),rectal adenocarcinoma(READ),and gastric cancer(STAD)(P <0.05),also common tumors such as breast invasive carcinoma(BRCA),lung adenocarcinoma(LUAD),lung squamous cell carcinoma(LUSC),prostate cancer(PRAD),thyroid cancer(THCA),endometrial cancer(UCEC)Medium to high expression.2.B7-H3 is highly expressed in adrenocortical carcinoma(ACC)(HR = 2.4,P = 0.033),bladder urothelial carcinoma(BLCA)(HR = 1.5,P = 0.011),colon cancer(COAD)(HR = 1.6,P = 0.048),head and neck squamous cell carcinoma(HNSC)(HR =1.4,P = 0.02),low-grade glioma of the brain(LGG)(HR = 2.3,P <0.001),hepatocellular carcinoma(LIHC)(HR = 1.5,P = 0.026),mesothelioma(MESO)(HR =3.4,P <0.001)and other tumors with poor OS;and high levels of B7-H3 in ACC(HR =3.7,P <0.001),DGF in poorly formed glioblastoma(GBM)(HR = 1.7,P = 0.012)and LGG(HR = 1.5,P = 0.017).3.The expression of B7-H3 was significantly positively correlated with the expression of TAM,M2 type macrophages and Treg cells(P<0.0001).4.B7-H3 has a certain degree of effectiveness in the treatment of BLCA,COAD,LGG,LIHC and other tumors PD-1(PDCD1),PD-L1(CD274),CTLA4,LAG3 and TIM3(HAVCR2)Positive correlation.5.Use CIBER-SORTx to detect COD M0,M2,Tregs,neutrophils and other cells infiltrated more in B7-H3 high expression samples(P <0.001).6.Using the Consensus TME method to analyze the B7-H3 expression group with a high level of immune scores in the lower level group was statistically different(P <0.001).7.Based on the TCGA database survival analysis,the high and low expression of B7-H3 is an independent prognostic risk factor and is statistically significant(HR = 1.8,95% CI: 1.15-2.81,P = 0.01).8.Based on the survival analysis of the GEO database in the GSE39582 data set,the expression of B7-H3 is also an independent prognostic risk factor and has statistical significance(HR= 1.38,95% CI: 1-1.89,P = 0.047).9.Combined with the survival data of patients with colorectal surgery at Union Medical College Hospital affiliated to Fujian Medical University,the survival analysis showed that the expression of B7-H3 was an independent prognostic risk factor for patients with abdominal cancer metastasis from colon cancer(HR = 1.67,95% CI: 1.38-2.03,P <0.001).10.B7-H3 CAR-T cells have a strong ability to specifically recognize and activate B7-H3 positive tumor cells,but have no obvious killing effect on B7-H3 negative tumor cells.11.The successful PDX model of in situ peritoneal metastasis can better simulate the microenvironment of peritoneal metastasis and retain the molecular characteristics of the original tissue.12.CAR-T cells targeting B7-H3 can effectively inhibit tumors in successfully constructed PDX in situ model mice and prolong the survival time of mice.Conclusion 1.B7-H3 is highly expressed in a variety of tumors and is related to prognosis.The high expression of B7-H3 in colon cancer indicates more Treg cells and M2 type macrophage infiltration,suggesting that B7-H3 is a potential immunotherapy Target.2.B7-H3 is an independent prognostic risk factor for patients with abdominal cancer metastasis from colon cancer.3.CAR-T cells targeting B7-H3 can effectively inhibit the growth of B7-H3 positive tumor cells and prolong the survival time of animal models. |
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