EP300 through upregulating the expression of vimentin to promote the progression of chordoma

OBJECTIVE There is a lack of effective drugs to treat the progression and recurrence of chordoma, which is widely resistant to treatment in chemotherapy. The authors investigated the functional and therapeutic relevance of the E1A-binding protein p300 (EP300) in chordoma. METHODS The expression of EP300 and vimentin was examined in specimens from 9 patients with primary and recurrent chordoma with immunohistochemistry. The biological functions of EP300 were evaluated with Cell Counting Kit-8, clonogenic assays, and transwell assays. The effects of EP300 inhibitors (C646 and SGC-CBP30) on chordoma cell motility were assessed with these assays. The effect of the combination of EP300 inhibitors and cisplatin on chordoma cells was evaluated with clonogenic assays. Reverse transcription quantitative polymerase chain reaction and Western blot techniques were used to explore the potential mechanism of EP300 through upregulation of the expression of vimentin to promote the progression of chordoma. RESULTS Immunohistochemistry analysis revealed a positive correlation between elevated EP300 expression levels and recurrence. The upregulation of EP300 stimulated the growth of and increased the migratory and invasive capabilities of chordoma cells, along with upregulating vimentin expression and consequently impacting their invasive properties. Conversely, EP300 inhibitors decreased cell proliferation and downregulated vimentin. Furthermore, the combination of EP300 inhibition and cisplatin exhibited an enhanced anticancer effect on chordoma cells, indicating that EP300 may influence chordoma sensitivity to chemotherapy. CONCLUSIONS These findings indicate that EP300 functions as an oncogene in chordoma. Targeting EP300 offers a novel approach to the development and clinical treatment of chordoma.