Background/Objectives: Death-associated protein kinase 1 (DAPK1) is a serine/threonine kinase that plays a crucial role in cancer by regulating apoptosis through interactions with TP53. Aberrant expression of DAPK1 was shown in certain types of human cancer contributing to tumor progression and chemoresistance. This study aimed to investigate the role of DAPK1 in high-grade serous ovarian cancer (HGSOC) and to evaluate the therapeutic potential of restoring its kinase activity, including the use of truncated DAPK1 variants, to overcome chemoresistance and enhance tumor suppression. Methods: Gene expression analysis was performed on ovarian cancer tissues compared to benign controls to assess DAPK1 downregulation and its epigenetic regulation. Prognostic relevance was evaluated in a cohort of 1436 HGSOC patient samples. Functional restoration of DAPK1 was conducted in HGSOC cell lines and patient-derived primary tumor cells using vector-based expression or in vitro-transcribed (IVT) DAPK1 mRNA, including the application of truncated DAPK1 (ΔDAPK1) forms. To assess apoptosis, Caspase activation assays, 2D-colony formation assays, and cell survival assays were performed. To analyze the reactivation of DAPK1 downstream signaling, phosphorylation of p53 at Ser20 and the expression of p53 target proteins were examined. Chemosensitivity to Paclitaxel and Cisplatin was quantified by changes in IC50values. Results: DAPK1 expression was significantly downregulated in ovarian cancer compared to benign tissue, correlating with epigenetic silencing, and showed prognostic value in early-stage HGSOC. Restoration of DAPK1 activity, including ΔDAPK1 variants, led to phosphorylation of p53 Ser20, increased expression of p53 target proteins, and Caspase-dependent apoptosis. Reactivation of DAPK1 sensitized both established HGSOC cell lines and patient-derived ascites cells to Paclitaxel and Cisplatin. These effects occurred through both p53-dependent and p53-independent pathways, enabling robust tumor suppression even in p53-mutant contexts. Conclusions: Reactivation of DAPK1, particularly through truncated variants, represents a promising therapeutic strategy to overcome chemoresistance in HGSOC. The dual mechanisms of tumor suppression provide a strong rationale for developing DAPK1-based therapies to enhance the efficacy of standard chemotherapy, especially in patients with chemoresistant or p53-deficient tumors. Future work should focus on optimizing delivery approaches for DAPK1 variants and assessing their synergistic potential with emerging targeted treatments in clinical settings.
背景/目的：死亡相关蛋白激酶1（DAPK1）是一种丝氨酸/苏氨酸激酶，通过与TP53相互作用调控细胞凋亡，在癌症中发挥关键作用。研究显示，DAPK1在特定类型的人类癌症中存在异常表达，促进肿瘤进展和化疗耐药。本研究旨在探讨DAPK1在高级别浆液性卵巢癌（HGSOC）中的作用，并评估恢复其激酶活性（包括使用截短型DAPK1变体）以克服化疗耐药和增强肿瘤抑制的治疗潜力。方法：通过对比卵巢癌组织与良性对照组织的基因表达分析，评估DAPK1的下调及其表观遗传调控。在1436例HGSOC患者样本队列中评估其预后相关性。在HGSOC细胞系和患者来源的原代肿瘤细胞中，通过载体表达或体外转录（IVT）DAPK1 mRNA（包括应用截短型DAPK1（ΔDAPK1）形式）实现DAPK1的功能恢复。为评估细胞凋亡，进行了Caspase活化实验、二维集落形成实验和细胞存活实验。为分析DAPK1下游信号通路的再激活，检测了p53 Ser20位点的磷酸化及p53靶蛋白的表达。通过IC50值的变化量化对紫杉醇和顺铂的化疗敏感性。结果：与良性组织相比，DAPK1在卵巢癌中表达显著下调，与表观遗传沉默相关，并在早期HGSOC中显示出预后价值。恢复DAPK1活性（包括ΔDAPK1变体）可导致p53 Ser20磷酸化、p53靶蛋白表达增加以及Caspase依赖性细胞凋亡。DAPK1的再激活使已建立的HGSOC细胞系和患者来源的腹水细胞对紫杉醇和顺铂的敏感性增强。这些效应通过p53依赖性和p53非依赖性途径共同实现，即使在p53突变背景下仍能产生强大的肿瘤抑制作用。结论：DAPK1的再激活，特别是通过截短变体实现，是克服HGSOC化疗耐药的一种有前景的治疗策略。其双重肿瘤抑制机制为开发基于DAPK1的疗法以增强标准化疗疗效提供了有力依据，尤其适用于化疗耐药或p53缺陷肿瘤患者。未来工作应聚焦于优化DAPK1变体的递送方法，并评估其与新兴靶向治疗在临床中的协同潜力。
肿瘤(癌症)患者之家