DataSheet1_Reactivation of mutant p53 in esophageal squamous cell carcinoma by isothiocyanate inhibits tumor growth.DOCX

p53 mutations are prevalent in human cancers; approximately half of patients with esophageal cancer present these mutations. Mutant p53 (mutp53) exerts oncogenic functions that promote malignant tumor progression, invasion, metastasis, and drug resistance, resulting in poor prognosis. Some small molecules have been shown to mitigate the oncogenic function of mutp53 by restoring its wild-type activity. Although these molecules have been evaluated in clinical trials, none have been successfully used in the clinic. Here, we investigated the antitumor effects of phenethyl isothiocyanate (PEITC) in p53-mutant esophageal squamous cell carcinoma (ESCC) and elucidated its mechanism to identify new therapeutic strategies. We observed that p53R248Q is a DNA contact mutation and a structural mutation and that PEITC can restore the activity of p53R248Qin vitro and in vivo, further clarifying the antitumor activity of PEITC in cancers with different types of p53 mutations. PEITC can inhibit ESCC growth, induce apoptosis, and arrest cell cycle progression and has a preferential selectivity for ESCC with p53 mutations. Mechanistic studies showed that PEITC induced apoptosis and arrested cells at G2/M transition in cells expressing the p53R248Q mutant by restoring the wild-type conformation and transactivation function of p53; these effects were concentration dependent. Furthermore, PEITC inhibited the growth of subcutaneous xenografts in vivo and restored p53 mutant activity in xenografts. According to these findings, PEITC has antitumor effects, with its ability to restore p53R248Q activity being a key molecular event responsible for these effects.

p53突变在人类癌症中普遍存在；约有一半的食管癌患者呈现出这些突变。突变型p53（mutp53）行使致癌功能，促进恶性肿瘤的进展、侵袭、转移和耐药性，导致预后不良。一些小分子已被证实可以通过恢复其野生型活性来减轻mutp53的致癌功能。尽管这些分子已在临床试验中进行评估，但尚未有成功应用于临床的案例。在本研究中，我们探讨了异硫氰酸苯乙酯（PEITC）在p53突变型食管鳞状细胞癌（ESCC）中的抗肿瘤作用，并阐明了其作用机制，以识别新的治疗策略。我们观察到p53R248Q是一种DNA接触突变和结构突变，并且PEITC能够在体外和体内恢复p53R248Q的活性，进一步阐明PEITC在不同类型p53突变癌症中的抗肿瘤活性。PEITC可以抑制ESCC的生长、诱导细胞凋亡并阻止细胞周期进程，且对具有p53突变的ESCC具有选择性。机制研究表明，PEITC通过恢复p53的野生型构象和转激活功能，在表达p53R248Q突变型的细胞中诱导细胞凋亡并阻止细胞周期在G2/M转换，这些效应呈浓度依赖性。此外，PEITC在体内抑制皮下异种移植的生长并恢复异种移植中的p53突变型活性。根据这些发现，PEITC具有抗肿瘤作用，其恢复p53R248Q活性的能力是这些效应的关键分子事件。