To investigate the effect and fat mass and obesity-associated protein (FTO) expression on tumor proliferation in glioblastoma (GBM) under hypoxic environment.

(1) Tumor tissue samples were collected from 15 GBM patients who underwent surgical resection at the Second Affiliated Hospital of Xinjiang Medical University from January 2021 to December 2024. Samples were collected from the peripheral, intermediate, and core regions, with 15 tumor tissue samples obtained from each region. Analyze the transcription and translation of FTO in different regions of GBM samples through Western blot and qRT-PCR; Using the GEO database (GSE78025) and cell models, U251-MG and LN229 cells were divided into normoxic, moderate hypoxic (1%O₂), and severe hypoxic (5%O₂) groups, and the differences in FTO expression under different conditions were analyzed. (2) Twenty-four 4-week-old Balb/c nude mice were selected, and U251-MG and LN229 cells pre stably infected with Lv-FTO or Lv-NC were subcutaneously inoculated into mice to construct xenograft tumor models. Each cell line was randomly divided into an FTO overexpression group (Lv-FTO group) and a negative control group (Lv-NC) using a random number table method, with 6 mice in each group. The changes in volume and mass of transplanted tumors in two groups of mice were observed and compared. The effect of FTO overexpression on GBM cell proliferation was explored, and the expression of PCNA, Vimentin, and Twist in transplanted tumor tissues was detected. (3) The expression changes of miR-27a-3p in GBM cells were detected under hypoxic conditions. Overexpression or inhibition of miR-27a-3p was achieved by transfecting agomir-27a-3p/antagomir-27a-3p, agomir-NC group, agomir-27a-3p group, antagomir-NC group, and antagomir-27a-3p group were set up, and its effects on FTO mRNA and protein expression were detected by qRT-PCR and Western blot.

(1) FTO exhibited regional expression differences in GBM tissue, with FTO mRNA and protein expression levels in the core and intermediate zones significantly lower than those in the peripheral zone (P<0.05); Compared with normoxic conditions, FTO expression in GBM cells was significantly downregulated under hypoxic conditions (P<0.05). (2) Compared with the Lv-NC control group, the Lv-FTO overexpression group in nude mice exhibited significantly smaller tumor volumes and lighter tumor weights (P<0.05). furthermore, the protein and mRNA expression levels of PCNA, Vimentin, and Twist in tumor tissues of the Lv-FTO group were all significantly lower than those in the Lv-NC group (P<0.05). (3) Compared with the normoxic group, miR-27a-3p expression was significantly upregulated in the hypoxic group (P<0.05); Compared with the agomir-NC group, FTO mRNA and protein expression were significantly reduced in the agomir-27a-3p group (P<0.05); Compared with the antagomir-NC group, FTO expression was significantly increased in the antagomir-27a-3p group (P<0.05).

FTO inhibits GBM cell proliferation by downregulating the expression of PCNA, Vimentin, and Twist; Under hypoxic conditions, FTO expression decreases, reducing its inhibitory effect on GBM proliferation; MiR-27a-3p negatively regulates FTO expression, indirectly promoting GBM proliferation.