APMAP regulated by YY1 transcription mediates ferroptosis and metastasis in non-small cell lung cancer through the PI3K/AKT/mTOR pathway.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide. Adipocyte Plasma Membrane Associated Protein (APMAP) is a glycosylated type II transmembrane protein, and APMAP induces malignant metastasis of colorectal cancer. However, the role and mechanism of APMAP in NSCLC remain unknown. We aimed to study the APMAP regulation on NSCLC. APMAP mRNA levels in NSCLC tissues were tested by quantitative reverse transcription-PCR (qRT-PCR). APMAP protein levels in NSCLC tissues and cells were determined via Western blot. Also, the association between APMAP expressions and NSCLC clinicopathology was assessed using Chi-square test. After silencing APMAP (sh-APMAP) in NSCLC cells, APMAP's roles in NSCLC were revealed by Western blot, Cell Counting Kit-8 (CCK-8) assay, Transwell, Fe level analysis, and immunofluorescence assays. Meanwhile, APMAP mechanism in NSCLC was verified through Human TFDB and PROMO databases, qRT-PCR, Western blot, dual-luciferase reporter assay, CCK-8 experiment, Transwell, analysis of Fe, reactive oxygen species levels, and Clinical Bioinformatics Home. Also, APMAP function in vivo was examined using a tumor xenograft model, immunohistochemistry assay, and Western blot. APMAP expressions were up-regulated in NSCLC tissues and cells. Moreover, patients with high APMAP expression exhibited a poorer overall survival rate. APMAP expression was closely related to TNM stage, distant metastasis, and tumor differentiation. Functionally, APMAP knockdown repressed NSCLC cell proliferation and invasion, and induced cell ferroptosis. Mechanistically, transcription factor YY1 induced APMAP expression. Meanwhile, APMAP expressions were decreased after interfering with YY1, while APMAP expressions were increased after overexpressing YY1. Also, co-transfection experiments demonstrated that YY1 overexpression enhanced the fluorescence intensity of APMAP-WT promoter. Importantly, YY1 overexpression promoted NSCLC cell proliferation and invasion, and repressed cell ferroptosis, yet these effects were reversed after APMAP knockdown. Moreover, knocking down APMAP reduced NSCLC proliferation in vivo, mainly through reduced tumor volume, reduced KI-67 and GPX4 expressions, and decreased p-pI3K, p-AKT, and p-mTOR protein levels. APMAP regulated by YY1 transcription enhanced NSCLC proliferation, invasion, and repressed cell ferroptosis via activating PI3K/AKT/mTOR.