Mechanism of sensitivity to TPF chemoagents and its potential alternative of erbB2 in oral cancer with GDF15 overexpression.

Abstract

e18542 Background: To explore the mechanism of sensitivity to docetaxel, cisplatin, and 5-fluorouracil (TPF) chemoagents in patients with oral squamous cell carcinoma (OSCC) and growth differentiation factor 15 (GDF15) overexpression recruited in a TPF induction chemotherapy trial; and to explore potential alternative agents for patients who might not benefit from TPF induction chemotherapy. Methods: GDF15-overexpression and silenced OSCC cells were used to investigate sensitivity to TPF chemoagents in vitro and in vivo. Immunoprecipitation combined with mass spectrometry was used to screen out the possible receptor for GDF15, and associated signaling pathways were detected after intervention with the possible receptor of GDF15. The efficacy of an inhibitor of the phosphorylation of the possible GDF15 receptor was evaluated by treatment of GDF15-overexpression OSCC cells in vitro and in vivo. Results: Overexpression of GDF15 in OSCC cell lines and xenografts lead to an increase of chemotherapeutics sensitivity on apoptosis effects induced by docetaxel, cisplatin and 5-fluorouracil, through a caspase -dependent pathway. Immunoprecipitation combined with mass spectrometry revealed that the erbB2 protein was a potential binding protein of GDF15, as verified by coimmunoprecipitation. When GDF15 was overexpressed, the phosphorylation of erbB2 and downstream PI3K/AKT and MAPK/ERK pathways was significantly upregulated, but was downregulated when GDF15 expression was interfered. The erbB2 phosphorylation inhibitor CI1033 significantly inhibited the proliferation and colony-forming ability of GDF15-overexpression OSCC cells as well as the growth of xenografts. CI1033 might be used as a potential targeted drug or alternative of TPF chemoagents for OSCC patients with GDF15 overexpression. Conclusions: OSCC with GDF15 overexpression exhibit sensitivity to TPF chemoagents through a caspase-dependent pathway. ErbB2 phosphorylation inhibitors might be used as potential targeted drugs or an alternative of TPF chemoagents for OSCC patients with GDF15 overexpression.