Induction Of Necrosis Of Human Neuroblastoma Cells By Histone Acetylase P300 Inhibitor C646

Objective:Neurobalstoma(NB)is the most common extracranial malignant solid tumor in children,which occurs in sympathetic nervous system arising from neuroblasts and nerve tissue of the adrenal gland,neck,chest,or spinal cord.Histone acetylase is a potential therapeutic target for the disease.As a new molecular target agent,C646 inhibits histone deacetylase in different kinds of human cancers.The aim of this study was to explore the effect and mechanism of acetylase P300 inhibitor(C646)on neuroblastoma.Methods:SH-SY5Y and Kelly human neuroblastoma cell lines were treated with different concentrations of C646.MTT assay was used to evaluate cell growth and morphology.Cell apoptosis and cycle were detected by flow cytometry.The expression of poly(ADP)-ribose polymerase 1(PARP1)and CCCTC-binding factor(CTCF)was analyzed by Western blot,and the interaction between PARP1 and CTCF was verified by immunoprecipitation.Nude mice subcutaneously treated with different concentrations of C646 were to observe the tumor size and detect the expression of PARP,CTCF and downstream genes of tumor suppressor.Results:C646 inhibited proliferation of SH-SY5Y and Kelly cells in a dose-dependent manner.The IC50 values of C646 in SH-SY5Y and Kelly cells were 9.1 and 36 respectively.Annexin V staining showed that the number of apoptotic cell in the C646 processing group is larger when compared with the control group for the SH-SY5Y and Kelly cells(p<0.05).Cell cycle experiments showed that the number of SH-SY5Y and Kelly G2 cells treated with C6464 decreased significantly compared with the control group(p<0.05).C646 inhibited the cloning of human neuroblastoma cells a dose-dependent manner.It was found that the number of clones of the two cells gradually decreased with the increase of drug concentration.The inhibition of 20μM/L concentration on the formation of the two cell clones was the most obvious.Western blot showed that the expression of PARP and CTCF protein in NB cells decreased with C646 concentration increasing.Co-immunoprecipitation suggested that C646 inhibited repressing PARP1-mediated activation of CTCF.The nude mice model treated with C646 results showed that the survival rate increased and tumor size reduced in the treatment group when compared with the control group(p<0.05).Conclusion:C646 inhibited proliferation of SH-SY5Y and Kelly cells in a dose-dependent manner.The apoptosis of SH-SY5Y and Kelly cells induced by C646 is mediated by PARP1.At the same time,C646 inhibits the development of neuroblastoma by repressing PARP1-mediated activation of CTCF and up-regulating the expression of tumor suppressor genes regulated by CTCF.PARP1 may be a potential therapeutic target for cancer,and C646 has the potential to become a new antitumor drug.