Fig. 2: FOXD1 knockdown promotes the senescence and apoptosis but inhibits the growth of HNSCC cells, whereas FOXD1 overexpression results in the opposite trend.

A The establishment of two HNSCC cell lines with knockdown and overexpression of FOXD1 was verified at the mRNA and protein levels. The (B) EdU, (C) CCK-8, and (D) colony formation assays showed that higher FOXD1 expression levels resulted in stronger proliferation abilities. E SA-β-gal staining showed that lower FOXD1 expression levels resulted in higher proportions of senescent tumor cells. F, G Cell cycle experiments showed that FOXD1 knockdown significantly increased the G0/G1 phase ratios and reduced the S phase ratios but that FOXD1 overexpression showed the opposite trend. H, I Apoptosis experiments showed that FOXD1 knockdown increased the percentage of apoptosis cells but that FOXD1 overexpression decreased the percentage of apoptosis cells. *p < 0.05, **p < 0.01, and ***p < 0.001. FOXD1 forkhead box D1, HNSCC head and neck squamous cell carcinoma, mRNA messenger RNA, EdU 5-Ethynyl-2’-deoxyuridine, SA-β-gal senescence-associated beta-galactosidase, SEM standard error of the mean.