Published in:
Open Access 01-12-2019 | Research
SP600125 enhances C-2-induced cell death by the switch from autophagy to apoptosis in bladder cancer cells
Published in: Journal of Experimental & Clinical Cancer Research | Issue 1/2019
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Background
A natural compound Jaspine B and its derivative possess potential anti-cancer activities; However, little is known about the underlying mechanism. Here, the role of a new autophagy inducer Jaspine B derivative C-2 in suppressing bladder cancer cells was researched in vitro and in vivo.
Methods
The underlying mechanisms and anticancer effect of C-2 in bladder cancer cells were investigated by MTT, western blotting, immunoprecipitation and immunofluorescence assays. The key signaling components were investigated by using pharmacological inhibitors or specific siRNAs. In vivo, we designed a C-2 and SP600125 combination experiment to verify the effectiveness of compound.
Results
C-2 exhibits cytotoxic effect on bladder cancer cells, and JNK activated by C-2 triggers autophagy and up-regulates SQSTM1/p62 proteins, contributing to activation of Nrf2 pathway. Utilization of JNK inhibitor SP600125 or knockdown of JNK by siRNA potentiate the cytotoxicity of C-2 through down-regulation of p62 and LC3II proteins and up-regulation of active-Caspase3 proteins, enhance the cell death effect, facilitating the switch from autophagy to apoptosis. In vivo study, C-2 suppresses tumor growth in a xenograft mouse model of EJ cells without observed toxicity. Combined treatment with SP600125 further enhances tumor inhibition of C-2 associated with enhanced activation of caspase3 and reduction of autophagy.
Conclusions
It reveals a series of molecular mechanisms about SP600125 potentiate the cytotoxicity and tumor inhibition of C-2 in bladder cancer cells through promoting C-2-induced apoptosis, expecting it provides research basis and theoretical support for new drugs development.