Sensitization of Pancreatic Cancers to Gemcitabine Chemoradiation by WEE1 Kinase Inhibition Depends on Homologous Recombination Repair.
Sensitization of Pancreatic Cancers to Gemcitabine Chemoradiation by WEE1 Kinase Inhibition Depends on Homologous Recombination Repair.
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DOI：
10.1016/j.neo.2015.09.006
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
Morgan MA
中科院分区：
文献类型：
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作者：
Kausar T;Schreiber JS;Karnak D;Parsels LA;Parsels JD;Davis MA;Zhao L;Maybaum J;Lawrence TS;Morgan MA
为了提高局部晚期胰腺癌放化疗的疗效，并开始建立患者选择标准，我们研究了WEE 1抑制剂AZD 1775与吉西他滨-放疗联合治疗同源重组（HR）修复完善型和缺陷型胰腺癌。在胰腺癌细胞中通过克隆形成存活率和在患者来源的异种移植物中通过肿瘤生长评估AZD 1775对吉西他滨辐射的致敏性。分别通过γ H2 AX、BRCA 2操作和RAD 51焦点形成和pHistone H3流式细胞术评估HR修复抑制和G2检查点消除对致敏的贡献。我们发现，AZD 1775在BRCA 2野生型胰腺癌细胞中对吉西他滨辐射敏感，但在BRCA 2突变型胰腺癌细胞中不敏感。在所有细胞中，AZD 1775均导致CDK 1磷酸化抑制和G2检查点消除。然而，AZD 1775的致敏作用与持续性γ H2 AX和抑制RAD 51病灶形成相关。在HR熟练（BRCA 2野生型）或缺乏（BRAC 2无效）的同基因细胞中，AZD 1775对BRCA 2野生型中的吉西他滨辐射敏感，但在BRCA 2无效细胞中不敏感，尽管G2检查点显著消除。在患者来源的胰腺肿瘤异种移植物中，AZD 1775显著抑制肿瘤生长，并损害了吉西他滨辐射后的RAD 51病灶形成。总之，AZD 1775抑制WEE 1是使胰腺癌对吉西他滨放化疗敏感的有效策略。尽管这种致敏伴随着CDK 1磷酸化的抑制和G2检查点的废除，但这种机制不足以致敏。我们的研究结果表明，通过WEE 1抑制导致的对化放疗的敏感性来自HR修复的抑制，并表明没有潜在HR缺陷的患者肿瘤将从这种治疗中获益最多。
To improve the efficacy of chemoradiation therapy for locally advanced pancreatic cancer and begin to establish patient selection criteria, we investigated the combination of the WEE1 inhibitor AZD1775 with gemcitabine-radiation in homologous recombination (HR) repair proficient and deficient pancreatic cancers. Sensitization to gemcitabine-radiation by AZD1775 was assessed in pancreatic cancer cells by clonogenic survival and in patient-derived xenografts by tumor growth. The contributions of HR repair inhibition and G2 checkpoint abrogation to sensitization were assessed by γH2AX, BRCA2 manipulation, and RAD51 focus formation and pHistone H3 flow cytometry, respectively. We found that AZD1775 sensitized to gemcitabine-radiation in BRCA2 wild-type but not BRCA2 mutant pancreatic cancer cells. In all cells, AZD1775 caused inhibition of CDK1 phosphorylation and G2 checkpoint abrogation. However, sensitization by AZD1775 was associated with persistent γH2AX and inhibition of RAD51 focus formation. In HR-proficient (BRCA2 wild-type) or -deficient (BRAC2 null) isogenic cells, AZD1775 sensitized to gemcitabine-radiation in BRCA2 wild-type, but not in BRCA2 null cells, despite significant G2 checkpoint abrogation. In patient-derived pancreatic tumor xenografts, AZD1775 significantly inhibited tumor growth and impaired RAD51 focus formation in response to gemcitabine-radiation. In conclusion, WEE1 inhibition by AZD1775 is an effective strategy for sensitizing pancreatic cancers to gemcitabine chemoradiation. Although this sensitization is accompanied by inhibition of CDK1 phosphorylation and G2 checkpoint abrogation, this mechanism is not sufficient for sensitization. Our findings demonstrate that sensitization to chemoradiation by WEE1 inhibition results from inhibition of HR repair and suggest that patient tumors without underlying HR defects would benefit most from this therapy.