TP53 mutations frequently occur in head and neck squamous cell carcinoma (HNSCC) patients without human papillomavirus infection. The recurrence rate for these patients is distinctly high. It has been actively explored to identify agents that target TP53 mutations and restore wild-type (WT) TP53 activities in HNSCC. PRIMA-1 (p53-reactivation and induction of massive apoptosis-1) and its methylated analogue PRIMA-1^Met (also called APR-246) were found to be able to reestablish the DNA-binding activity of p53 mutants and reinstate the functions of WT p53. Herein we report that piperlongumine (PL), an alkaloid isolated from Piper longum L., synergizes with APR-246 to selectively induce apoptosis and autophagic cell death in HNSCC cells, whereas primary and immortalized mouse embryonic fibroblasts and spontaneously immortalized non-tumorigenic human skin keratinocytes (HaCat) are spared from the damage by the co-treatment. Interestingly, PL-sensitized HNSCC cells to APR-246 are TP53 mutation-independent. Instead, we demonstrated that glutathione S-transferase pi 1 (GSTP1), a GST family member that catalyzes the conjugation of GSH with electrophilic compounds to fulfill its detoxification function, is highly expressed in HNSCC tissues. Administration of PL and APR-246 significantly suppresses GSTP1 activity, resulting in the accumulation of ROS, depletion of GSH, elevation of GSSG, and DNA damage. Ectopic expression of GSTP1 or pre-treatment with antioxidant N-acetyl-L-cysteine (NAC) abrogates the ROS elevation and decreases DNA damage, apoptosis, and autophagic cell death prompted by PL/APR-246. In addition, administration of PL and APR-246 impedes UMSCC10A xenograft tumor growth in SCID mice. Taken together, our data suggest that HNSCC cells are selectively sensitive to the combination of PL and APR-246 due to a remarkably synergistic effect of the co-treatment in the induction of ROS by suppression of GSTP1.

中文翻译：

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Piperlongumine 和 p53 重激活剂 APR-246 通过靶向 GSTP1 选择性诱导 HNSCC 细胞死亡。


TP53突变经常发生在未感染人乳头瘤病毒的头颈鳞状细胞癌（HNSCC）患者中。这些患者的复发率明显很高。人们正在积极探索识别针对 TP53 突变并恢复 HNSCC 中野生型 (WT) TP53 活性的药物。 PRIMA-1（p53-重新激活和诱导大量凋亡-1）及其甲基化类似物 PRIMA-1 ^Met （也称为 APR-246）被发现能够重建 p53 突变体的 DNA 结合活性并恢复 p53 突变体的功能。 WT p53。在此，我们报道了胡椒碱（PL），一种从胡椒中分离出来的生物碱，与 APR-246 协同作用，选择性诱导 HNSCC 细胞凋亡和自噬性细胞死亡，而原代和永生化小鼠胚胎成纤维细胞以及自发永生化非致瘤性人类皮肤角质形成细胞 (HaCat) 不会因联合治疗而受到损伤。有趣的是，PL 对 APR-246 敏感的 HNSCC 细胞与 TP53 突变无关。相反，我们证明谷胱甘肽 S-转移酶 pi 1 (GSTP1) 在 HNSCC 组织中高度表达，GSTP1 是一种 GST 家族成员，催化 GSH 与亲电化合物的结合以实现其解毒功能。给予 PL 和 APR-246 显着抑制 GSTP1 活性，导致 ROS 积累、GSH 耗尽、GSSG 升高和 DNA 损伤。 GSTP1 的异位表达或用抗氧化剂 N-乙酰基-L-半胱氨酸 (NAC) 进行预处理可以消除 PL/APR-246 引起的 ROS 升高并减少 DNA 损伤、细胞凋亡和自噬性细胞死亡。此外，给予 PL 和 APR-246 会阻碍 SCID 小鼠中 UMSCC10A 异种移植肿瘤的生长。 综上所述，我们的数据表明，HNSCC 细胞对 PL 和 APR-246 的组合选择性敏感，因为联合治疗在通过抑制 GSTP1 诱导 ROS 方面具有显着的协同作用。