Abstract

Background The strategy of limiting the availability of tumor cell phosphoglycerate dehydrogenase (PHGDH) has become a potential treatment for cancer. Modulation of the tumor-derived serine synthesis pathway to reprogram the tumor microenvironment represents a viable approach to optimize the efficacy of anti-tumor immunotherapy. However, currently no reliable PHGDH inhibitors of natural product origin have been approved for clinical use, and the precise pharmacological mechanisms underlying their biological activity have not yet been fully elucidated. Purpose This study aims to identify PHGDH inhibitors from natural products and elucidate the underlying anti-tumor pharmacological mechanisms. Methods Multiple public databases were utilized to analyze the correlation between PHGDH and human non-small cell lung cancer (NSCLC) in this study. We took advantage of a natural compound library to perform the compound screening of PHGDH inhibitors. The binding capacity of DHT I to PHGDH was examined using molecular docking simulations, cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS), and microscale thermophoresis (MST). Co-immunoprecipitation and western blotting assays were employed to investigate the regulatory effect of DHT I on PRMT1-mediated monomethylation of PHGDH. The roles of DHT I in PHGDH-mediated serine synthesis pathway in the lung cancer cells were determined through metabolomics analysis. Western blotting analysis was performed to examine the regulatory impact of DHT I on histone H3 lysine 4 methylation (H3K4me). Quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were utilized to determine the effects of DHT I on the transcriptional and secretory levels of IL-10 and TGF-β. Co-culture assays of tumor cells and bone marrow-derived macrophages (BMDMs) were performed to investigate DHT I-mediated polarization of macrophages. Single-cell RNA sequencing (scRNA-seq) analysis was performed to eluc