Objective:To investigate the mechanism of neurofibromin 1 (NF1) in gallbla-dder cancer.Methods:The experimental study was conducted. Human gallbladder cancer cell lines, including GBC-SD, NOZ, SGC996, EH-GB1, ZJU0428, human embryonic kidneys cell line 293T and human cervical cancer cell line HELA, were cultured. The recombinant plasmids (mRFP-YAP1 FL-FLAG and eGFP-MYC-NF1 2650?2750-HA) were constructed for co-immunoprecipitation experiment. The truncated Yes associated protein 1(YAP1) and NF1 recombinant proteins were purified in vitro. The interaction between NF1 and YAP1 in vitro or in vivo were verified by isothermal titration calori-metry (ITC) assay, GST pull-down experiment, co-immunoprecipitation, immunofluorescence, laser confocal microscopy, and the expression of NF1 protein in different gallbladder cancer cell lines was verified by Western blot experiments. Observation indicators: (1) interaction between NF1 and YAP1 in vitro; (2) interaction between NF1 and YAP1 in cells; (3) expression of NF1 protein in different human gallbladder cancer cell lines. The dissociation constants were exported from ITC 200 software and represented as Mean± SD. Count data were represented as absolute numbers. Results:(1) Interaction between NF1 and YAP1 in vitro. ① Results of ITC assay showed that there was interac-tion between PPQY and YAP1-WW1, between PPQY and YAP1 (Amino acid residues 162?275), and the dissociation constants between PPQY and YAP1-WW1, between PPQY and YAP1(Amino acid residues 162?275) were (0.42±0.06)mmol/L, (0.69±0.14)mmol/L, respectively. ② GST pull-down results indicated that the target protein His-Sumo-YAP1 WW1 was obviouly observed in protein lane of reaction system between GST-PPQY recombinant protein and His-Sumo-YAP1 WW1, relative to the reaction system between GST protein and His-Sumo-YAP1 WW1. The target protein His-Sumo-YAP1 WW2 was obviouly observed in protein lane of reaction system between GST-PPQY recombinant protein and His-Sumo-YAP1 WW2, relative to the reaction system between GST protein and His-Sumo-YAP1 WW2. (2) Interaction between NF1 and YAP1 in cells. ① Co-immunoprecipitation results indica-ted that NF1 protein was observed in cell lysis solution which was incubated by FLAG gel beads and cotransfected with mRFP-YAP1 FL-FLAG and eGFP-MYC-NF1 2650?2750-HA. ② Immuno-fluorescence and laser confocal microscopy results indicated that YAP1 and NF1 with obvious fluorescence were co-localized in the cytoplasm of human gallbladder cancer NOZ cells. However, YAP1 with obvious fluorescence was localized in the nucleus of human gallbladder SGC996 cells and NF1 showed weak fluorescence. (3) Expression of NF1 protein in different human gallbladder cancer cell lines. Western blot results showed that with the expression level of NF1 protein in HELA cell line as the standard, the relative expression levels of NF1 protein in EH-GB1, GBC-SD, NOZ, SGC996, ZJU0428 cell lines were 1.28, 0, 1.01, 0, 0, respectively. Conclusion:NF1 affects the gallbladder cancer by directly acting on YAP1 protein.

BACKGROUND: Gallbladder cancer (GBC) is the most common malignant tumor of biliary tract. Isoliquiritigenin (ISL) is a natural compound with chalcone structure extracted from the roots of licorice and other plants. Relevant studies have shown that ISL has a strong anti-tumor ability in various types of tumors. However, the research of ISL against GBC has not been reported, which needs to be further investigated. METHODS: The effects of ISL against GBC cells in vitro and in vivo were characterized by cytotoxicity test, RNA-sequencing, quantitative real-time polymerase chain reaction, reactive oxygen species (ROS) detection, lipid peroxidation detection, ferrous ion detection, glutathione disulphide/glutathione (GSSG/GSH) detection, lentivirus transfection, nude mice tumorigenesis experiment and immunohistochemistry. RESULTS: ISL significantly inhibited the proliferation of GBC cells in vitro . The results of transcriptome sequencing and bioinformatics analysis showed that ferroptosis was the main pathway of ISL inhibiting the proliferation of GBC, and HMOX1 and GPX4 were the key molecules of ISL-induced ferroptosis. Knockdown of HMOX1 or overexpression of GPX4 can reduce the sensitivity of GBC cells to ISL-induced ferroptosis and significantly restore the viability of GBC cells. Moreover, ISL significantly reversed the iron content, ROS level, lipid peroxidation level and GSSG/GSH ratio of GBC cells. Finally, ISL significantly inhibited the growth of GBC in vivo and regulated the ferroptosis of GBC by mediating HMOX1 and GPX4 . CONCLUSION ISL induced ferroptosis in GBC mainly by activating p62-Keap1-Nrf2-HMOX1 signaling pathway and down-regulating GPX4 in vitro and in vivo . This evidence may provide a new direction for the treatment of GBC.
Animals ; Mice ; Carcinoma in Situ ; Chalcones/pharmacology* ; Ferroptosis ; Gallbladder Neoplasms/genetics* ; Glutathione Disulfide ; Kelch-Like ECH-Associated Protein 1 ; Mice, Nude ; NF-E2-Related Factor 2/genetics* ; Reactive Oxygen Species ; Humans