Feiwei Heji Enhances Antitumor Immunity by MLL4-Dependent Regulation of Pyroptosis in Lung Cancer

Feiwei Heji (FWHJ) is a traditional Chinese medicine formula used for lung cancer with Qi-Yin deficiency. This study investigated the antitumor effect of FWHJ on lung cancer and explored the underlying mechanisms. The major chemical components of FWHJ were identified by HPLC. Lewis lung carcinoma (LLC) tumor-bearing mice received oral FWHJ at different doses. Tumor histopathology was assessed by H&E and TUNEL staining. Expression of MLL4, pyroptosis-related proteins (NLRP3, caspase-1, and GSDMD), and inflammatory cytokines (IL-1β and IFN-β) was detected by Western blot, immunohistochemistry, and ELISA. Tumor-infiltrating immune cells were evaluated by flow cytometry. An MLL4 overexpression model was established to validate the role of MLL4 in the antitumor effects of FWHJ. HPLC analysis showed that FWHJ primarily contains naringin, chlorogenic acid, amygdalin, and harpagoside. Oral FWHJ significantly inhibited tumor growth, upregulated NLRP3, caspase-1, and GSDMD, as well as their cleaved forms, and increased the release of IL-1β and IFN-β, indicating the activation of pyroptosis. FWJH also enhanced antitumor immunity, characterized by an increased CD8⁺/CD4⁺ T cells ratio and elevated proportion of CD28⁺ and IFN-γ⁺ CD8⁺ T cells in the tumor microenvironment. Mechanistically, FWHJ significantly downregulated MLL4 expression, and MLL4 overexpression largely attenuated its antitumor and immune-enhancing effects. These findings suggest that FWHJ suppresses lung cancer progression by downregulating MLL4, activating pyroptosis, and promoting immune cell infiltration, highlighting that MLL4 may serve as a key regulator mediating the antitumor effects of FWHJ.