FKBP11 promotes cell proliferation and tumorigenesis via p53-related pathways in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is one of the causes of cancer-related death worldwide. The abnormal proliferation ability of OSCC has become one of the major reasons for its poor prognosis. FK-506 binding protein 11 (FKBP11) is abnormally expressed in malignant tumors and affects many biological processes. The purpose of this study is to investigate the effect of FKBP11 on cell proliferation in OSCC and explore the possible regulatory mechanism. The expression of FKBP11 was detected by western blotting (WB) and/or real-time PCR in OSCC and paracancerous normal tissues in tongue squamous cell carcinoma (TSCC) cell lines, revealing high expression in OSCC and CAL-27 cells. Furthermore, FKBP11 knockdown inhibited the proliferation of CAL-27 cells by CCK-8 and colony formation assays. G/M arrest and induction of apoptosis were observed using flow cytometry, Hoechst 33258 and Calcein-AM/PI staining, accompanied by changes in some cell cycle- and apoptosis-related proteins, including CDK1, Cyclin B1, p21, p27, p53, Bax, Bcl-2 and Caspase-3. Additionally, the expression of these proteins can be reversed by the use of pifithrin-α (PFT-α), a p53 inhibitor. An in vivo xenograft model further confirmed that FKBP11 enhanced OSCC progression. In conclusion, FKBP11 could promote cell proliferation by regulating G/M phase and apoptosis via the p53/p21/p27 and p53/Bcl-2/Bax pathways, respectively, which suggests that it may be a new candidate target for the treatment of OSCC.