sepantronium and Esophageal-Squamous-Cell-Carcinoma

Survivin and transcription factor p65 (NF‑κB p65) participate in the progression of esophageal squamous cell carcinoma (ESCC). However, the mechanism of NF‑κB p65 activation in ESCC remains to be elucidated. The aim of the present study was to investigate the role of survivin in the activation of NF‑κB p65 in ESCC. The expression levels of survivin, NF‑κB p65, inhibitor of nuclear factor κB kinase subunit α (IKKα) and inhibitor of nuclear factor κB kinase subunit β (IKKβ) were detected in ESCC tissue samples. Eca109 and KYSE150 cells were cultured and survivin activity was modulated via transfection with an overexpression plasmid, a small hairpin RNA plasmid and a specific inhibitor. Quantitative reverse transcription-polymerase chain reaction and western blotting assays were conducted to assess the effects of survivin on the expression levels of IKKα, IKKβ and NF‑κB p65. Cell cycle and apoptosis assays were conducted to detect surviving-dependent cellular behavior changes. In addition, the luciferase reporter gene assay and chromatin immunoprecipitation assay were conducted to determine the genomic sites responsible for surviving-induced activation of NF‑κB p65. The present study demonstrated that the expression of survivin is positively correlated with IKKα and IKKβ in ESCC tissues. Survivin affected the mRNA and protein expression levels of IKKα, IKKβ, and NF‑κB p65 in Eca109 and KYSE150 cells. Furthermore, survivin increased the transcriptional activity of the IKKβ promoter and bound to the IKKβ promoter region in the Eca109 cells. Downregulation of survivin arrested the cell cycle at the G2/M phase and induced apoptosis. Results of the present study suggest that survivin activates NF‑κB p65 in Eca109 cells via binding to the IKKβ promoter region and upregulating IKKβ promoter transcriptional activity. Survivin overexpression activates NF‑κB p65, which is important in the acquisition and maintenance of the oncogenic characteristics of ESCC.

Topics: Apoptosis; Carcinoma, Squamous Cell; Cell Count; Cell Line, Tumor; Cell Survival; Chromatin Immunoprecipitation; Down-Regulation; Esophageal Neoplasms; Esophageal Squamous Cell Carcinoma; G2 Phase Cell Cycle Checkpoints; Gene Knockdown Techniques; Humans; I-kappa B Kinase; Imidazoles; Inhibitor of Apoptosis Proteins; Naphthoquinones; Promoter Regions, Genetic; Protein Binding; RNA, Small Interfering; Survivin; Transcription Factor RelA; Up-Regulation

Survivin is overexpressed in cancer cells and plays a crucial role in apoptosis evasion. YM155, a small-molecule inhibitor of survivin, could enhance the cytotoxicity of various DNA-damaging agents. Here, we evaluated the radiosensitizaion potential of YM155 in human esophageal squamous cell carcinoma (ESCC).. Cell viability was determined by CCK8 assay. The radiosensitization effect of YM155 was evaluated by clonogenic survival and progression of tumor xenograft. Cell cycle progression was determined by flow cytometric analysis. Radiation-induced DNA double strand break (DSB) and homologous recombination repair (HRR) were detected by the staining of γ-H2AX and RAD51, respectively. Expression of survivin and cell cycle regulators was detected by Western blot analysis.. YM155 induced radiosensitization in ESCC cell lines Eca109 and TE13, associated with the abrogation of radiation induced G2/M checkpoint, impaired Rad51 focus formation, and the prolongation of γ-H2AX signaling. G2/M transition markers, including the activation of cyclinB1/Cdc2 kinase and the suppression of Cdc2 Thr14/Tyr15 phosphorylation were induced by YM155 in irradiated cells. The combination of YM155 plus irradiation delayed the growth of ESCC tumor xenografts to a greater extent compared with either treatment modality alone.. Our findings suggest that the abrogation of G2 checkpoint and the inhibition of HRR contribute to radiosensitization by YM155 in ESCC cells.

Topics: Animals; Antineoplastic Agents; Blotting, Western; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Survival; Esophageal Neoplasms; Esophageal Squamous Cell Carcinoma; Flow Cytometry; Fluorescent Antibody Technique; G2 Phase Cell Cycle Checkpoints; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Radiation-Sensitizing Agents; Recombinational DNA Repair; Survivin; Xenograft Model Antitumor Assays