HIF1A and glioblastoma: To investigate the function of HIF-1α protein in GBM, we first assessed the proliferation of GBM cells using the CCK8 assay and found that under hypoxic conditions, the proliferation capacity of U87 and U251 cells in the shRNA-HIF-1α group began to decline after 24 hours of culture, and with extended culture periods (36-48 hours), their proliferation ability was significantly reduced compared to the shRNA-NC group (Figure 2D-E).