[A study on the effect of aqueous extract of Euphorbia helioscopia on improving immune environment and inhibiting the formation of pulmonary tumor nodules].

Objective To explore the effect and mechanism of aqueous extract of Euphorbia helioscopia L. (EHE) on improving the immune environment and inhibiting lung tumor nodules induced by lipopolysaccharide (LPS) combined with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in mice. Methods Male BALB/c mice were randomly divided into 6 groups: normal group, model group, Euphorbia helioscopia water extract low-, medium-, and high-dose groups (0.9, 1.8, 3.6 g/kg), and aspirin group (20 mg/kg). Samples were collected after 25 weeks. HE and immunohistochemistry staining were used to detect tumor lesions in lung tissues. Western blot was performed to determine the expression of oncoproteins in lung tissues. Real-time fluorescence quantitative PCR and flow cytometry were employed to detect the mRNA levels of immune-related molecule genes and the percentage of immune cells in lung tissues, respectively. Additionally, Western blot was used to detect the expression of proteins related to immune regulatory pathways. Results HE and immunohistochemistry staining revealed that LPS combined with NNK induced the formation of adenomatous tumor nodules in mice, with high expression of thyroid transcription factor 1 (TTF-1) in the lungs. Compared with the model group, the Euphorbia helioscopia-treated groups exhibited a significant reduction in the number of lung tumor nodules, decreased expression of the oncoprotein c-Myc and anti-apoptotic protein Bcl2, and increased expression of the pro-apoptotic protein BAX. The mRNA levels of immune-related molecules in lung tissues, including S100 calcium-binding protein A9 (S100A9), cyclooxygenase 2 (COX2), granulocyte-macrophage colony-stimulating factor (GM-CSF), chemokine ligand 1 (CXCL1), monocyte chemoattractant protein 1 (MCP-1), interleukin 10 (IL-10), and IL-4, were significantly downregulated. In lung tissues, the percentage of macrophages increased, while the percentage of myeloid-derived suppressor cells (MDSCs) decreased. In the spleen, the percentages of regulatory T cells (Tregs) and MDSCs were reduced. The protein expression levels of programmed death ligand 1 (PD-L1), cluster of differentiation 47 (CD47), phosphorylated nuclear factor κB p65 subunit (p-NF-κB p65), and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) were decreased. Conclusion The aqueous extract of Euphorbia helioscopia L. can effectively inhibit LPS/NNK-induced formation of lung adenoma nodules by improving the immune environment, and its mechanism may involve regulating the activation of NF-κB and STAT3.