Mechanism Of Lung Cancer Cell Growth Promotion By Talaromyces Marneffei Through Induction Of Immunosuppressive Macrophages

Purpose:With the development of sequencing technology,microbial communities in the human body have become a hot research topic.Microbial communities play a crucial role in human physiology under stable conditions,and dysbiosis of microbial populations leads to pathological changes such as inflammation and even tumors.Lung cancer is one of the leading causes of cancer deaths worldwide,and smoking and environmental pollution are the main causes of its pathogenesis.A growing number of studies have shown the involvement of microorganisms in the development and progression of lung cancer.A study on tumor microbiome confirmed the detection of microorganisms as well as microbial composition in tumor cells,including lung cancer.The study further confirmed that microorganisms within tumors are mainly found in tumor cells and immune cells.In the present study,macrogenomic sequencing of bronchial lavage from patients with non-small cell lung cancer revealed significant differences in the abundance of Talaromyces marneffei(TM)in bronchial lavage from tumor and non-tumor patients.It exists in the form of intracellular parasites.Macrophages are a major cell population in the tumor microenvironment and play a role in immune homeostasis.It has been shown that tumor-associated macrophages not only promote tumorigenesis and metastasis,but also exhibit immunosuppressive activity and promote tumor angiogenesis.However,few studies have now investigated the mechanism of macrophage polarization and changes in cytokines and metabolism after TM infection with macrophages,and the effects of macrophages on non-small cell lung cancer after infection are not yet clear.The aim of this study was to investigate the polarization phenotype and functional changes of macrophages after TM infection and their mechanisms,and to investigate the role of post-infection macrophages on the generation of non-small cell lung cancer.Methods: In this study,we examined the microbial community composition of bronchial lavage fluid from non-small cell lung cancer patients and non-tumor control patients by macrogenomic sequencing.We constructed a co-culture system of TM and macrophages,and analyzed the polarization,cytokine and metabolite alterations of macrophages and the effect of macrophages on LLC cell growth after TM infection by flow cytometry,metabolomics and Qpcr.Results:Macrogenomic sequencing results showed significant differences in fungal concentrations between bronchial lavage fluid and non-tumor controls in patients with non-small cell lung cancer,and TM was found to exhibit significant differences in multiple dimensions.Exploring further,we found that flow cytometry results showed that both CD86+ and CD206+ cells grew with increasing infection concentration after TM infection,but M2-type cells grew significantly faster than M1-type cells,and macrophages expressing Arg-1,IL-10,IL-1,TNF-α,and IL-6 significantly increased after TM infection,which promoted LLC cell proliferation in the macrophage environment.By metabolomic analysis we found that the Arginine and proline metabolism pathway was significantly upregulated in macrophages after infection,and Ornithine,a product of the Arg-1 response in this pathway,was also significantly increased.We used the arginase inhibitor NOR-NOHA to significantly reduce the promotion of LLC cells by macrophages after TM infection,demonstrating that Arginine metabolism mediated by Arg-1 is one of the mechanisms involved in the response to TM infection of macrophages.In addition,we found that TM infection of macrophages upregulated the expression of its immunotherapeutic target PD-1.Conclusion:(1)Lung fungal abundance was higher in non-small cell lung cancer patients than in non-tumor controls,and Talaromyces marneffei was significantly more abundant in bronchial lavage fluid of non-small cell lung cancer patients than in non-tumor controls.(2)Talaromyces marneffei promoted lung cancer cell proliferation by promoting macrophage M2-type polarization;(3)Talaromyces marneffei promoted tumor cell proliferation through arginine-mediated immunosuppressive macrophage differentiation.