演題抄録

International Session

開催概要
開催回
第55回・2017年・横浜
 

進行直腸癌におけるγH2AXの術前放射線治療感受性予測バイオマーカーとしての役割

演題番号 : IS6-2

[筆頭演者]
革島 悟史:1 
[共同演者]
田代 圭太郎:2、近藤 圭策:3、田中 慶太朗:2、奥田 準二:2、内山 和久:2

1:社会医療法人医真会八尾総合病院・消化器センター外科、2:大阪医科大学・附属病院・消化器外科、3:医療法人達瑛会鳳胃腸病院・消化器外科

 

[Background] Preoperative chemoradiotherapy (PRT) for rectal cancer has been one of the standard therapies in terms of anus preservation, reduction of local recurrence and down staging for the operation. In practice, the efficiency of PRT varies among different individuals clinically. Validated predictor has not been indicated yet. It was revealed that γH2AX expression level significantly and gradually increased during tumor progression in human colorectal cancer. It was also shown that fraction of γH2AX after irradiation was correlated with radiosensitivity in 18 human cell lines in vitro. We hypothesized the expression level of γH2AX was the predictor of radiosensitivity in PRT for advanced rectal cancer.
[Aim] We reveal the relationship between the expression of γH2AX and PRT for colorectal cancer in vivo and vitro experiments.
[Results] 1. We examined the histopathological expression of γH2AX protein using resected sections of advanced rectal cancer treated PRT. For result, cancer cells with expression of γH2AX tended to cell death by PRT. 2. We examined the expression level of γH2AX in vitro after irradiation using DLD-1 cells. The expression of γH2AX were significantly decreased by radiation dose depended manner. For result, cancer cells expressed γH2AX were easier to cell death by irradiation. 3. We subsequently knocked down γH2AX gene expression using H2AX si-RNA transfection, these si-RNA transfected cells were exposed by irradiation, and conducted MTT assay. Whereas the survival cells significantly decreased in control cells without si-RNA radiation dependent manner, the cells transfected si-RNA remained to survive as control level by irradiation. For result, H2AX gene knocked down cancer cells tended to survive after irradiation.
[Conclusion] Cancer cells with expression of γH2AX imply easy to cell death by PRT. The expression of γH2AX has possibility to predict radiosensitivity before PRT for advanced colorectal cancer.

キーワード

臓器別:大腸・小腸

手法別:バイオマーカー

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