Screening Of Bone Metastasis-Related Proteins In Prostate Cancer Based On Proteomics

Objective: Bone metastasis of prostate cancer significantly reduces the quality of life and survival of patients.In this study,label-free quantitative proteomics technology was used to analyze the changes of protein expression in bone metastasis pathological samples of prostate cancer(MT group),high-grade primary prostate cancer pathological samples(Gleason>7 scores)(HT group),low-grade primary prostate cancer pathological samples(Gleason≤7 scores)(LT group)and benign prostatic hyperplasia pathological samples(N group).The differentially expressed proteins were further screened by immunohistochemistry.It is expected to find differentially expressed proteins related to bone metastasis in the process of prostate cancer progression and bone metastasis,and provide a direction for the clinicopathological diagnosis of bone metastasis of prostate cancer.Methods: In this study,label-free quantitative proteomics technology was used to analyze the differentially expressed proteins in MT group,HT group,LT group and N group(n=3).GO/KEGG enrichment analysis was performed on differentially expressed proteins.Nine significantly differentially expressed proteins(MT group vs non-MT group)were selected from autophagy signaling pathway,lysosome-related proteins and tumor metabolic process-related proteins.The related proteins in the four groups(n=7)were further analyzed and verified by immunohistochemistry.Two chief pathologists independently performed immunohistochemical readings by double-blind method,gave immunohistochemical results scores,and collected clinicopathological data and demographic information of patients.SPSS26.0 software was used for statistical analysis of immunohistochemical results and clinicopathological data.When P<0.05,it was statistically significant.Results: Proteomics GO/KEGG enrichment analysis showed that differentially expressed proteins appeared in different comparison groups.When MT group was compared with non-MT group(HT group,LT group and N group),there were significantly differentially expressed proteins in autophagy signaling pathway,lysosome-related proteins and tumor metabolic process-related proteins.Among them,CTSA,CTSD,LAMP1,LAMP2,VAMP8 and RRAS are related to the autophagy process of tumors,and IMPDH2,COX6 C and GSTM1 are related to the metabolic process of tumors.The expression of six proteins(CTSA,CTSD,LAMP1,LAMP2,COX6 C,IMPDH2)was up-regulated in the bone metastasis group(MT group)compared with the non-bone metastasis group(non-MT group),and the expression of two proteins(GSTM1 and RRAS)was down-regulated in the MT group compared with the non-MT group.Immunohistochemical analysis further confirmed that the expression of VAMP8 was up-regulated in bone metastasis of prostate cancer,and the difference in immunohistochemical scores between bone metastasis group and non-bone metastasis group was statistically significant(P<0.05).Analysis of clinicopathological parameters showed that the expression of VAMP8 was significantly correlated with prostate cancer stage(UICC version 3,2020)(P<0.05),but not with age,PSA and Gleason score(P>0.05).Conclusion: Proteomics GO / KEGG protein enrichment analysis and immunohistochemical analysis verified that VAMP8 is a prostate cancer bone metastasis-related protein and may be involved in the process of prostate cancer bone metastasis.