Jianpi‐Tiaoqi decoction inhibits tumour proliferation and lung metastasis in tumour‐bearing mice with triple‐negative breast cancer

Abstract Traditional Chinese medicine, specifically the Jianpi Tiaoqi (JPTQ) decoction, has been explored for its role in treating breast cancer, particularly in inhibiting lung metastasis in affected mice. Our study evaluated the effects of JPTQ on several factors, including tumour growth, apoptosis, angiogenesis, epithelial‐to‐mesenchymal transition (EMT) and immune microenvironment regulation. We used bioluminescence imaging to observe in situ tumour growth and potential lung metastasis. Transcriptomic analysis provided insights into gene expression, whereas flow cytometry was used to examine changes in specific immune cells, such as CD4 + T cells and myeloid‐derived suppressor cells. Several essential proteins and genes, including vascular endothelial growth factor (VEGF), matrix metalloprotein‐9 (MMP‐9) and B‐cell lymphoma 2 (Bcl‐2), were assessed through quantitative real‐time polymerase chain reaction, western blotting and immunohistochemistry. Our findings showed that JPTQ treatment inhibited tumour proliferation in cancer‐bearing mice. Bioluminescence imaging and pathological analysis indicated a reduction in lung metastasis. Transcriptome analysis of lung and tumour tissues indicated that the genes associated with EMT, angiogenesis, proliferation and apoptosis were regulated in the JPTQ‐treated group. Kyoto Encyclopedia of Genes and Genomes analysis suggested enrichment of immune‐related pathways. Flow cytometry indicated that JPTQ treatment reduced the proportion of monocyte–myeloid‐derived suppressor cells in the lung and increased the number of CD4 + T cells in the peripheral blood and the number of T helper 1 (Th1) cells in the spleen ( P < 0.05). E‐cadherin and cleaved caspase 3 were upregulated, whereas Snail, Bcl‐2, Ki67 and VEGF were downregulated in the lung and tumour tissues; moreover, the expression of MMP‐9 was downregulated in the lung tissue ( P < 0.05). In essence, JPTQ not only inhibits tumour growth in affected mice, but also promotes positive immune responses, reduces angiogenesis, boosts tumour cell apoptosis, reverses EMT and decreases breast cancer lung metastasis.