[Mechanism of n-butanol fraction of Wenxia Formula extract in ameliorating cisplatin resistance in lung cancer via CAFs-mediated glutathione synthesis].

This study aims to investigate the mechanism by which the n-butanol fraction of Wenxia Formula extract(NWXF) reverses cisplatin(DDP) resistance in lung cancer via targeting cancer-associated fibroblasts(CAFs)-mediated regulation of glutathione(GSH) synthesis. A combined in vivo and in vitro experimental approach was employed to examine the therapeutic effects and molecular mechanisms of NWXF in ameliorating DDP resistance: a subcutaneous tumor xenograft model in nude mice was established in vivo. The mice injected with non-small cell lung cancer cells(A549) were randomly divided into control group and DDP group, while those injected with A549+CAFs cells were divided into CAFs group, CAFs+DDP group, NWXF+CAFs group, and NWXF+CAFs+DDP group. Hematoxylin-eosin(HE) staining was utilized to observe tumor histomorphological changes. TUNEL staining and immunohistochemistry were employed to detect tumor apoptosis. DTNB assay was used to measure the GSH level, and Western blot was employed to detect expressions of glutamate-cysteine ligase catalytic subunit(GCLc), glutamate-cysteine ligase regulatory subunit(GCLm), and recombinant solute carrier family 7 member 11(SLC7A11) proteins. A conditioned co-culture model with A549 cells was constructed in vitro. Cell counting kit-8(CCK-8) assay was employed to detect A549 cell proliferation, and flow cytometry was used to measure apoptosis. DTNB was used to determine the levels of GSH and cysteine(Cys), and Western blot was utilized to examine the expressions of GCLc, GCLm, and SLC7A11 proteins. In vivo results demonstrated that compared to the CAFs+DDP group, the NWXF+CAFs+DDP group exhibited markedly reduced tumor volume, significant tumor necrosis, obviously increased apoptosis, and apparently downregulated GSH level and expressions of GCLc, GCLm, and SLC7A11 proteins. In vitro results showed that the IC_(50) of DDP in A549 was significantly declined under the conditioned medium treated with NWXF. Compared to the CAFs-CM+DDP group, the NWXF-CAFs-CM+DDP group displayed significantly increased apoptosis, significantly decreased levels of GSH and Cys, and significantly downregulated expressions of GCLc, GCLm, and SLC7A11 proteins. In conclusion, NWXF may ameliorate resistance to DDP in lung cancer by inhibiting CAFs-mediated GSH synthesis.