Vitamin D Regulates The Phenotype Of Monocyte-macrophages To Affect The Occurrence And Development Of Hepatocellular Carcinoma

Background & AimsHepatocellular carcinoma is characterized by insidious onset,rapid progression and poor clinical prognosis.At present,there is still a lack of effective treatment strategies and prognostic biomarkers.Epidemiological studies have shown that vitamin D is at a low level in patients with chronic liver disease and liver cancer,suggesting that vitamin D levels may be associated with the occurrence of chronic liver disease.Although there are also large cohort studies showing that vitamin D is associated with the occurrence and prognosis of liver cancer,the conclusions are controversial and have not yet been determined.Although previous studies have confirmed that vitamin D can inhibit the occurrence and development of liver cancer,most of them focus on the direct impact on tumor cells,while ignoring the impact of immune microenvironment on liver cancer.In the immune microenvironment of liver cancer,vitamin D receptor(VDR)is highly expressed in non-parenchymal cells of the liver,especially mononuclear-macrophages and stellate cells,suggesting that its effect on hepatocellular carcinoma is mainly achieved by acting on non-parenchymal cells of the liver.However,how it affects the occurrence of hepatocellular carcinoma by regulating the immune microenvironment of the tumor is still unknown,especially the effect on mononuclear-macrophages.Therefore,studying the effect of vitamin D on the occurrence and development of hepatocellular carcinoma from the perspective of immune microenvironment is expected to provide new therapeutic targets and effective prognostic markers for hepatocellular carcinoma.Methods1.To establish a spontaneous model of liver cancer in situ with diethylnitrosamine and carbon tetrachloride,and explore the effect of vitamin D analogue Paricalcitol on the occurrence and development of liver cancer.2.Conduct single cell transcriptome sequencing during the development of liver cancer to dynamically analyze the indirect effects of vitamin D on the development and progression of liver cancer,namely,the regulatory role of vitamin D on the immune microenvironment;Focus on monocyte-macrophage with high expression of VDR,and explore the effect of vitamin D on monocyte-macrophage typing,proportion change and interaction with tumor cells.3.Based on the transcriptome sequencing data and corresponding clinical prognosis information of liver cancer patients in the Cancer Genome Atlas(TCGA)database,the relationship between vitamin D and the prognosis of liver cancer patients is analyzed from the perspective of bioinformatics,and a genetic risk score related to vitamin D is established to determine the prognosis of liver cancer patients,thereby guiding clinical practice.Results1.The VDR activator Paricalcitol can delay liver inflammation,fibrosis process and the occurrence of liver cancer.However,in the progression of liver cancer,it may induce macrophages to polarize to M2-like phenotype,resulting in poor therapeutic effect,may promote the progress of liver cancer,and cause poor prognosis of patients.2.In the tumor immune microenvironment,the expression of VDR is the highest in monocytes and macrophages,and almost no expression in tumor cells;In the process of hepatocarcinogenesis in mice,Paricalcitol can affect the infiltration level of most immune cells in the immune microenvironment;For mononuclear-macrophages,in the pre-cancerous samples,Paricalcitol can promote the increase of their M2-like phenotype score,in the paracancerous samples,promote the increase of their M1-like phenotype score,and in the cancerous samples,promote the increase of their M1 and M2-like phenotype score;In addition,Paricalcitol can recruit two groups of M1 like,VDR highly expressed monocytes and macrophages,namely,Il1r2+monocytes and Ly6i+macrophages,in paracancerous and cancerous tissues,reducing their CD44 expression level and thereby weakening their SPP1-CD44 receptor binding with tumor cells.3.Based on the TCGA database,25 differential genes related to Vitamin D and prognosis of hepatocellular carcinoma patients were screened,and the risk score of hepatocellular carcinoma was constructed.The risk score was closely related to the prognosis of patients with hepatocellular carcinoma,clinical characteristics of tumor and tumor immune microenvironment.ConclusionThis study confirms that vitamin D can alleviate liver damage,delay the progression of liver inflammation and fibrosis,and inhibit the occurrence of liver cancer.However,during the progression of liver cancer,vitamin D may have poor efficacy and may promote tumor progression,suggesting that vitamin D can be used as a drug for liver cancer prevention,but it should be used cautiously in the treatment of liver cancer;Secondly,it is revealed from the single cell level that vitamin D can affect the occurrence and development of liver cancer by regulating the phenotype of mononuclear macrophages.Targeting SPP1-CD44 ligand receptor is expected to improve the therapeutic effect of vitamin D on liver cancer;Finally,the vitamin Drelated gene risk score based on TCGA database can judge the prognosis of liver cancer patients and guide clinical practice.