The Significance Of IDO Expression And Related Clinical Value In PD-1 Combined Chemotherapy Neoadjuvant Therapy Resistant NSCLC Patients

Background: Immune checkpoint inhibitors,represented by PD-1 drugs,combined with chemotherapy have shown an outstanding therapeutic effect and safety in clinical trials of non-small cell lung cancer(NSCLC).However,there were a few reported of the efficacy of PD-1-based immunochemotherapy in clinical.Major pathological response(MPR)has been widely recognized as a survival surrogate endpoint for neoadjuvant therapy,but its clinical significance to cancer treatment needs to be further clarified by real-world studies.Clinical trials indicated that the MPR rate of PD-1combined with platinum-containing double drugs in locally advanced non-small cell lung cancer treatment was approximately reached 50%.On the other hand,nearly half of the patients still fail to achieve MPR.Studies have confirmed that immunosuppressive molecules represented by IDO are one of the main causes of immunochemotherapy resistance,however,the exploration of related biological mechanisms is mostly focused on cell or animal experiments,and there is a lack of research evidence based on clinical samples.Therefore,this research plans to review the clinical data of patients receiving PD-1 combined with chemotherapy in the real world,evaluate the therapeutic effect of this therapeutic regimen in clinical,and the correlation between MPR and survival.Furthermore,we plan to use clinical samples of treatment-sensitive and treatment-resistant patients to explore the significance,potential mechanism,and related clinical value of IDO molecule expression in NSCLC patients.Methods: From March 2020 to March 2023,the clinical data and treatment outcomes of patients diagnosed with locally advanced non-small cell lung cancer and received PD-1 combined with platinum-based double-drug chemotherapy in our hospital were collected retrospectively,and figured the clinical remission rate in radiographical and pathological measures.The incidence of adverse events and survival were also recorded.Tumor tissue,peripheral blood,and stool samples were collected prospectively before and after neoadjuvant chemotherapy combined with immunotherapy.High-throughput sequencing was used to screen IDO and other differential genes of patients with treatment remission and treatment resistance,and immunohistochemistry and fluorescent quantitative PCR were used to verify the expression of differential genes.The levels of peripheral blood lymphocytes and cytokines were detected by flow cytometry,and the differential immune factors of patients in the treatment-sensitive group and the treatment-resistant group were screened.The correlation between different immune factors and IDO molecules was analyzed,and the regulatory factors of IDO molecule expression were screened.16 S r RNA gene sequencing method was used to detect and analyze the differences in the composition and diversity of intestinal microorganisms in treatment-resistant and treatment-sensitive patients before treatment,and to analyze the correlation between the different microorganisms and peripheral blood immune cells and molecules,and the relationship between the two and the treatment outcome.Identify potential links between gut microbes,immune factors,and the tumor microenvironment.Results: The imaging objective response rate of 97 patients in our center who received PD-1 combined with platinum-containing double-drug neoadjuvant therapy and completed surgery was 76.3%,the main pathological response rate was 46.4%,and the incidence of grade 3 and above adverse reactions was 14.4%.The recurrence-free survival time of patients who achieved major pathological responses was significantly better than that of patients who did not meet the criteria of major pathological response.The results of next-generation sequencing,fluorescent quantitative PCR,and immunohistochemistry all showed that IDO molecules were significantly enriched in lesions of patients with treatment resistance,and IDO molecules were significantly enriched in lesions of patients with treatment resistance in biopsy lesions before treatment.Multicolor immunofluorescence and immunohistochemical analysis showed that IDO molecules were mainly expressed in the tumor stroma,and almost not expressed in tumor cells.The levels of IL-5,IL-10,and IFN-γ in the peripheral blood of treatment-resistant patients were significantly higher than those of treatmentsensitive patients,and the concentrations of IL-17 F,NK cells,and NK T cells in the peripheral blood of treatment-sensitive patients were significantly higher than those of treatment-resistant patients.The IFN-γ transcription level in the lesion and the plasma IFN-γ concentration was significantly correlated with the expression level of IDO molecules,and both exert a negative effect on the treatment outcome.The gut microbial composition and diversity were significantly different between treatmentresistant and treatment-sensitive patients,and the α-diversity of treatment-sensitive patients was significantly higher than that of treatment-resistant patients.Eubacterium coprostanoligenes,Christensenellaceae R 7 group,Oscillospirales UCG 010,and other bacterial genera treatment positively correlated were positively correlated with positive immune factors such as NK cells,while negatively correlated with immune factors such as IFN-γ and IL-10.On the contrary,Bacteroides,Enterococcus,Bifidobacterium,and other negatively correlated bacteria were positively correlated with IFN-γ,IL-10,and other negative immune factors,and negatively correlated with positive immune factors such as NK cells and active T cells.Conclusion: PD-1 combined with platinum-containing double-drug chemotherapy as a neoadjuvant therapy for locally advanced non-small cell lung cancer has shown high efficacy and safety in clinical practice.IDO molecules,as immune negative regulatory molecules,play an important role in mediating the resistance of PD-1 combined with chemotherapy in neoadjuvant therapy.IFN-γ produced in the lesion and the peripheral blood is an important factor that induces the overexpression of IDO molecules and leads to immunotherapy resistance.The curative effect-related intestinal flora was significantly correlated with peripheral blood lymphocytes and cytokines,and the impact of the two on the treatment outcome was in the same direction.Bacteria such as Enterococcus and Bifidobacterium may be one of the important factors that lead to higher levels of IFN-γ in patients and induce immunotherapy resistance.Gut microbes can interact with the immune system to regulate the levels of various immune factors and thus play an important role in regulating anti-tumor immunity and anti-tumor immunotherapy.