Drug-dependent functionalization of wild-type and mutant p53 in cisplatin-resistant human ovarian tumor cells.
Drug-dependent functionalization of wild-type and mutant p53 in cisplatin-resistant human ovarian tumor cells.
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DOI：
10.18632/oncotarget.14228
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发表时间：
2017-02-14
期刊：
影响因子：
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通讯作者：
Siddik ZH
中科院分区：
文献类型：
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作者：
Bhatt M;Ivan C;Xie X;Siddik ZH
p53功能障碍引起的肿瘤细胞顺铂耐药是一个重要的临床问题。虽然突变可以抑制p53功能，但根据文献报道，>60%的p53突变体保持正常功能。因此，我们研究了p53在顺铂耐药卵巢肿瘤模型中的状态及其对cis-Pt和机制上不同的非交叉耐药奥沙利铂（oxali-Pt）的功能反应。相对于携带野生型p53的敏感A2780细胞，2780 CP/Cl-16、OVCAR-10、Hey和OVCA-433细胞系对顺式铂的抗性为10至30倍，但基本上被草酸铂规避。2780 CP/Cl-16（p53 V172 F）和OVCAR-10（p53 V172 F和p53 G266 R）细胞中的突变型p53（在p53数据库中预测为无功能）显示对顺式铂的反应减弱，HEY和OVCA-433细胞系中的多态性p53 P72 R（功能上等同于野生型p53）也是如此。然而，p53在所有细胞系中被oxali-Pt稳健地激活，使用CRISPR/Cas9系统通过p53敲除证实所得药物效力为p53依赖性的。基于抑制剂和激酶研究，草酸铂对p53的激活与MEK 1/2在Ser 20的磷酸化有关。然而，由于下调Chk 2，Cis-Pt未能磷酸化Ser 20，根据TCGA数据库，其临床影响通过降低卵巢癌患者的总生存率来验证。总之，顺式铂耐药发生在野生型和突变型p53卵巢癌细胞，但与损失的Ser 20磷酸化。然而，这些突变型p53，像多态性p53，是功能性的，并激活草酸铂诱导的Ser 20磷酸化。因此，存在将奥沙利铂或类似药物用于治疗携带野生型或特异性突变型p53的难治性癌症的可能性。
Cisplatin (cis-Pt) resistance in tumor cells from p53 dysfunction is a significant clinical problem. Although mutation can inhibit p53 function, >60% of p53 mutants retain normal function according to literature reports. Therefore, we examined the status of p53 in cisplatin-resistant ovarian tumor models and its functional response to cis-Pt and the mechanistically-distinct non-cross-resistant oxaliplatin (oxali-Pt). Relative to sensitive A2780 cells harboring wild-type p53, the 2780CP/Cl-16, OVCAR-10, Hey and OVCA-433 cell lines were 10- to 30-fold resistant to cis-Pt, but was substantially circumvented by oxali-Pt. Mutant p53 in 2780CP/Cl-16 (p53V172F) and OVCAR-10 (p53V172F and p53G266R) cells, predicted as non-functional in p53 database, displayed attenuated response to cis-Pt, as did the polymorphic p53P72R (functionally equivalent to wild-type p53) in HEY and OVCA-433 cell lines. However, p53 was robustly activated by oxali-Pt in all cell lines, with resultant drug potency confirmed as p53-dependent by p53 knockout using CRISPR/Cas9 system. This p53 activation by oxali-Pt was associated with phosphorylation at Ser20 by MEK1/2 based on inhibitor and kinase studies. Cis-Pt, however, failed to phosphorylate Ser20 due to downregulated Chk2, and its clinical impact validated by reduced overall survival of ovarian cancer patients according to TCGA database. In conclusion, cis-Pt resistance occurs in both wild-type and mutant p53 ovarian cancer cells, but is associated with loss of Ser20 phosphorylation. However, these mutant p53, like polymorphic p53, are functional and activated by oxali-Pt-induced Ser20 phosphorylation. Thus, the potential exists for repurposing oxali-Pt or similar drugs against refractory cancers harboring wild-type or specific mutant p53.