Selinexor targeting XPO1 promotes PEG3 nuclear accumulation and suppresses cholangiocarcinoma progression.

Background: The role of selinexor, a targeted inhibitor of exportin 1 (XPO1), in the treatment of cholangiocarcinoma is not yet fully understood. This study conducted comprehensive in vitro and in vivo investigations to elucidate the effects of selinexor on cholangiocarcinoma, with a focus on its mechanistic relationship with the cellular localization of Paternally Expressed Gene 3 (PEG3).

Methods: A patient-derived xenograft (PDX) model was established using samples from a cholangiocarcinoma patient in immunodeficient mice to assess the in vivo effects of selinexor. Additionally, cholangiocarcinoma cell lines HuCC-T1 and BRE were cultured to evaluate selinexor's impact on cell proliferation, invasion, migration, cell cycle, and apoptosis. HuCC-T1 cells were also implanted in immunodeficient mice for further investigation. Immunofluorescence and Western blotting were employed to observe the expression and localization of the PEG3 protein.

Results: The results demonstrated that selinexor significantly inhibited tumor growth in the cholangiocarcinoma PDX model and promoted the accumulation of PEG3 protein within the nuclei of tumor cells. In vitro experiments showed that selinexor effectively suppressed cholangiocarcinoma cell proliferation, invasion, and migration, while also impeding the cell cycle and inducing apoptosis. Notably, selinexor markedly facilitated the nuclear accumulation of PEG3 protein in cholangiocarcinoma cells. However, when PEG3 expression was knocked down, the effects of selinexor on cholangiocarcinoma were significantly reversed.

Conclusion: These findings suggest that selinexor inhibits the progression of cholangiocarcinoma by targeting XPO1 and promoting the nuclear accumulation of PEG3 protein, thereby hindering the cell cycle and inducing apoptosis.