| Malignant tumors are a major class of diseases that threaten human health,with the rapid development of scientific technology over the years,the treatments for tumors have been improved.Among them,the approval of immune checkpoint inhibitors(ICI),including antibodies against programmed cell death protein 1(PD1)/programmed cell death-ligand 1(PDL1)has improved the prognosis of patients in a variety of tumors,but some patients can not benefit from them,so the research for efficacy biomarkers is critical.In this thesis,for the lack of effective efficacy biomarkers for anti-PD1 antibodies,we screened the plasma autoantibodies in patients treated with anti-PD1 antibodies in various tumors,identified and validated several tumor-specific autoantibody biomarkers.On the other hand,we have used in-depth plasma proteomics technique to study the dynamic changes of blood proteins pre-and post-immunotherapy in patients with different therapeutic efficacy.The main content is divided into two sections:Section 1.Plasma autoantibody profiling identifies efficacy biomarkers of anti-PDl antibody therapy in cancer patientsStudies have confirmed that autoantibodies have shown great potential in tumor screening,early diagnosis,and prognosis evaluation.The present study was conducted to further explore the potential of autoantibody as anti-PD1 antibody efficacy biomarkers as follows.Chapter 1:We screened the autoantibody profiling in 45 plasma samples before receiving anti-PD1 antibody treatment using high-throughput protein microarray technology,including lymphoma,non-small cell lung cancer(NSCLC)and alveolar soft tissue sarcoma(ASPS)patients,23 potential autoantibody biomarkers were selected based on the correlation analysis of detection signal with efficacy and related literature reports,these autoantibodies were subsequently validated using enzyme linked immunosorbent assay(ELISA).The results showed that patients with lymphoma,NSCLC and ASPS have different autoantibody expression profiles,and we identified therapeutic autoantibody markers for each cancer type based on the correlation with clinical outcomes.The anti-PD1 and P53 autoantibodies are therapeutic biomarkers for ASPS,anti-SIX2 autoantibody is efficacy biomarker in NSCLC,anti-EIF4E2,PD1 IgG2 and PDL1 IgG2 autoantibodies are predictive markers for lymphoma,and finally we validated anti-SIX2 and EIF4E2 autoantibodies in NSCLC and lymphoma cohorts,respectively.The results suggest that anti-SIX2 and EIF4E2 are highly promising biomarkers with good distinguish ability for different clinical outcomes.Chapter 2:To explore the distribution of anti-PDl and PDL1 autoantibodies in different cancer types and the relationship with prognosis of receiving anti-PD1 antibody therapy,we examined the distribution of anti-PD1 and PDL1 autoantibodies in the plasma of a total of 190 patients from ten cancer types including lung cancer,breast cancer,esophageal cancer,colorectal cancer,liver cancer,prostate cancer,cervical cancer,ovarian cancer,gastric cancer and lymphoma.The relationship between the levels of these two autoantibodies and prognosis was analyzed in a cohort of 76 NSCLC patients receiving anti-PD1 antibodies.The results showed that anti-PD1 and PDL1 autoantibodies were widely detected in cancer patients,IgG1 and IgG2 were predominant subtypes.Survival analysis showed that anti-PD1 IgG4 was associated with poor prognosis of anti-PD1 antibodies,suggesting that PD1 IgG4 is a potential therapeutic biomarker for anti-PD1 antibodies.Section 2.Plasma protein changes pre-and post-anti-PD1 antibody treatment and therapeutic biomarker study using in-depth plasma proteomicsThere is a wide variety of proteins in human blood,in clinical practice the quantification of some blood proteins was used for diagnosis or prognosis evaluation of diseases,but there are more clinical applications of blood proteins waiting to be developed.The current research on proteomics mainly relies on mass spectrometry,but low abundance proteins are to some extent masked by high abundance proteins and are difficult to be detected,antibody microarrays are capable of detecting lower abundance proteins,and deep plasma proteomics technologies that combine mass spectrometry and microarray platforms can achieve comprehensive coverage of blood proteins.The aim of this study is to examine longitudinal plasma samples using deep plasma proteomics technique,to explore the characteristics of plasma proteome changes pre-and post-treatment,and further identify efficacy biomarkers for anti-PD1 therapy.The details of the study are as follows.A total of 263 plasma samples from 117 patients of three cancer types before and after anti-PD1 antibodies treatment were included and examined using in-depth plasma proteomics technology.The results showed that the in-depth proteomics platform established by combining antibody microarray and mass spectrometry technology was able to detect more than 1000 plasma proteins and covered different types of proteins with different functions.By analyzing the differences in pre-treatment blood proteins in patients with different responses to anti-PD1 antibodies,we found multiple immune-related pathways、tumors/infection/autoimmune diseases-related pathways were activated.We then analyzed the pattern of changes in plasma proteins before and after anti-PD1 antibody treatment and found that the IL17 signaling pathway decreased,while the vitamin digestion and absorption pathways increased after treatment in patients with good response in all three cancer types.Finally,potential efficacy markers were validated using an independent lymphoma cohort,5 protein biomarkers were successfully validated,including FLT4、SFTPB、GNPTG、F5 and IL17A protein.Both parts of the above study explored the efficacy markers of anti-PD1 antibodies in terms of autoantibodies and proteins from blood,blood samples are easy to obtain and repeatable,the blood biomarkers obtained from the study have potential clinical translational advantages and certain application prospects.The results of this study can provide experimental basis and new ideas for the study of efficacy biomarkers for anti-PD1 antibody therapy in cancer patients and the development of clinical practice. |
PDF Full Text Request