Targeting PI3K and RAD51 in Barrett's adenocarcinoma: impact on DNA damage checkpoints, expression profile and tumor growth.
Targeting PI3K and RAD51 in Barrett's adenocarcinoma: impact on DNA damage checkpoints, expression profile and tumor growth.
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发表时间：
2012-03
影响因子：
2.5
通讯作者：
Jagannath Pal;M. Fulciniti;P. Nanjappa;Leutz Buon;Y. Tai;P. Tassone;N. Munshi;M. Shammas
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文献类型：
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作者：
Jagannath Pal;M. Fulciniti;P. Nanjappa;Leutz Buon;Y. Tai;P. Tassone;N. Munshi;M. Shammas
癌症中的磷脂酰肌醇3-激酶（PI 3 K）/v-akt鼠胸腺瘤病毒癌基因同源物1（AKT）信号传导涉及多种存活途径，包括重组酶（RAD 51）的调节。在这项研究中，我们评估了PI 3 K和RAD 51作为靶点在巴雷特腺癌（BAC）细胞在体外和体内。在PI 3 K抑制剂（渥曼青霉素）的存在下培养BAC细胞系（OE 19、OE 33和FLO-1），并测定对AKT、磷酸化AKT（P-AKT）和RAD 51的生长和表达的影响。Wortmannin可诱导AKT高表达的两株BAC细胞系（OE 33和OE 19）生长停滞和凋亡。具有较低AKT表达的FLO-1细胞对治疗较不敏感，并进一步研究。在FLO-1细胞中，渥曼青霉素抑制共济失调毛细血管扩张和Rad 3相关蛋白（ATR）-检查点激酶1（CHK 1）介导的检查点和多个DNA修复基因，而RAD 51和CHK 2不受影响。Western blotting证实wortmannin在OE 33和OE 19细胞中抑制了RAD 51，但在FLO-1细胞中没有。抑制FLO-1细胞中的RAD 51下调CHK 2和CHK 1的表达，并降低增殖潜力。最后，在FLO-1细胞中抑制RAD 51显著增加了渥曼青霉素在这些细胞中的体外和体内抗癌活性。我们表明，PI 3 K信号和hsRAD 51，通过不同的作用，在DNA损伤反应和修复途径，提供生存优势BAC细胞。在具有AKT固有低表达的细胞中，RAD 51不受PI 3 K抑制的影响，并提供了额外的存活途径。同时抑制PI 3 K和RAD 51，特别是在AKT表达较低的细胞中，可以显著降低其增殖潜力。
Phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog 1 (AKT) signaling in cancer is implicated in various survival pathways including regulation of recombinase (RAD51). In this study, we evaluated PI3K and RAD51 as targets in Barrett's adenocarcinoma (BAC) cells both in vitro and in vivo. BAC cell lines (OE19, OE33, and FLO-1) were cultured in the presence of PI3K inhibitor (wortmannin) and the impact on growth and expression of AKT, phosphorylated-AKT (P-AKT), and RAD51 was determined. Wortmannin induced growth arrest and apoptosis in two BAC cell lines (OE33 and OE19), which had relatively higher expression of AKT. FLO-1 cells, with lower AKT expression, were less sensitive to treatment and investigated further. In FLO-1 cells, wortmannin suppressed ataxia telangiectasia and Rad3-related protein (ATR)-checkpoint kinase 1 (CHK1)-mediated checkpoint and multiple DNA repair genes, whereas RAD51 and CHK2 were not affected. Western blotting confirmed that RAD51 was suppressed by wortmannin in OE33 and OE19 cells, but not in FLO-1 cells. Suppression of RAD51 in FLO-1 cells down-regulated the expression of CHK2 and CHK1, and reduced the proliferative potential. Finally, the suppression of RAD51 in FLO-1 cells, significantly increased the anticancer activity of wortmannin in these cells, both in vitro and in vivo. We show that PI3K signaling and hsRAD51, through distinct roles in DNA damage response and repair pathways, provide survival advantage to BAC cells. In cells with inherent low expression of AKT, RAD51 is unaffected by PI3K suppression and provides an additional survival pathway. Simultaneous suppression of PI3K and RAD51, especially in cells with lower AKT expression, can significantly reduce their proliferative potential.