Phosphorylation of TFCP2L1 by CDK1 is required for stem cell pluripotency and bladder carcinogenesis

Molecular programs involved in embryogenesis are frequently upregulated in oncogenic dedifferentiation and metastasis. However, their precise roles and regulatory mechanisms remain elusive. Here, we showed that CDK1 phosphorylation of TFCP2L1, a pluripotency‐associated transcription factor, orchestrated pluripotency and cell‐cycling in embryonic stem cells (ESCs) and was aberrantly activated in aggressive bladder cancers (BCs). In murine ESCs, the protein interactome and transcription targets of Tfcp2l1 indicated its involvement in cell cycle regulation. Tfcp2l1 was phosphorylated at Thr177 by Cdk1, which affected ESC cell cycle progression, pluripotency, and differentiation. The CDK1‐TFCP2L1 pathway was activated in human BC cells, stimulating their proliferation, self‐renewal, and invasion. Lack of TFCP2L1 phosphorylation impaired the tumorigenic potency of BC cells in a xenograft model. In patients with BC, high co‐expression of TFCP2L1 and CDK1 was associated with unfavorable clinical characteristics including tumor grade, lymphovascular and muscularis propria invasion, and distant metastasis and was an independent prognostic factor for cancer‐specific survival. These findings demonstrate the molecular and clinical significance of CDK1‐mediated TFCP2L1 phosphorylation in stem cell pluripotency and in the tumorigenic stemness features associated with BC progression. Synopsis Aberrant activation of pluripotency genes is frequently observed in tumors. Thr177‐phosphorylation of TFCP2L1 by CDK1 stimulates pluripotency and cell cycling in embryonic stem cells and stemness features of bladder cancers, potentiating the tumorigenesis and aggressive behavior of bladder cancer. CDK1 phosphorylates TFCP2L1 at Thr177 in both murine embryonic stem cells (mESCs) and human bladder cancer cells. Thr177 phosphorylation of TFCP2L1 by CDK1 is essential for pluripotency and cell cycle progression of mESCs via its ability to regulate cell cycle, pluripotency and developmental gene expression. Activation of CDK1‐TFCP2L1 pathway enhances the stemness features and tumorigenesis of bladder cancer cells. Activation of the CDK1‐TFCP2L1 cascade is associated with aggressive features of bladder cancer: high tumor grade, lymphovascular invasion, muscularis‐propria invasion, metastasis to distant organs, and low patient survival rates. Graphical Abstract Aberrant activation of pluripotency genes is frequently observed in tumors. Thr177‐phosphorylation of TFCP2L1 by CDK1 stimulates pl