Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Oncology, Peking University Cancer Hospital and Institute, 1 Life Park Road, Life Science Park of Zhongguancun, Changping, Beijing, 102206, P.R. China.
Department of Oncology, Peking University International Hospital, Beijing, 102206, China.
Mol Cancer. 2022 Jan 4;21(1):11. doi: 10.1186/s12943-021-01466-9.
Hepatocellular carcinoma (HCC) is among the most common forms of cancer and is associated with poor patient outcomes. The emergence of therapeutic resistance has hampered the efficacy of targeted treatments employed to treat HCC patients to date. In this study, we conducted a series of CRISPR/Cas9 screens to identify genes associated with synthetic lethality capable of improving HCC patient clinical responses.
CRISPR-based loss-of-function genetic screens were used to target 18,053 protein-coding genes in HCC cells to identify chemotherapy-related synthetic lethal genes in these cells. Synergistic effects were analyzed through in vitro and in vivo analyses, while related mechanisms were explored through RNA-seq and metabolomics analyses. Potential inhibitors of identified genetic targets were selected through high-throughput virtual screening.
The inhibition of phosphoseryl-tRNA kinase (PSTK) was found to increase HCC cell sensitivity to chemotherapeutic treatment. PSTK was associated with the suppression of chemotherapy-induced ferroptosis in HCC cells, and the depletion of PSTK resulted in the inactivation of glutathione peroxidative 4 (GPX4) and the disruption of glutathione (GSH) metabolism owing to the inhibition of selenocysteine and cysteine synthesis, thus enhancing the induction of ferroptosis upon targeted chemotherapeutic treatment. Punicalin, an agent used to treat hepatitis B virus (HBV), was identified as a possible PSTK inhibitor that exhibited synergistic efficacy when applied together with Sorafenib to treat HCC in vitro and in vivo.
These results highlight a key role for PSTK as a mediator of resistance to targeted therapeutic treatment in HCC cells that functions by suppressing ferroptotic induction. PSTK inhibitors may thus represent ideal candidates for overcoming drug resistance in HCC.
肝细胞癌 (HCC) 是最常见的癌症之一，患者预后较差。治疗耐药性的出现阻碍了迄今为止用于治疗 HCC 患者的靶向治疗的疗效。在这项研究中，我们进行了一系列 CRISPR/Cas9 筛选，以确定与合成致死性相关的基因，这些基因能够改善 HCC 患者的临床反应。
使用基于 CRISPR 的基因敲除遗传筛选靶向 HCC 细胞中的 18053 个编码蛋白基因，以鉴定这些细胞中与化疗相关的合成致死基因。通过体外和体内分析分析协同作用，通过 RNA-seq 和代谢组学分析探讨相关机制。通过高通量虚拟筛选选择鉴定的遗传靶标的潜在抑制剂。
发现抑制磷酸丝氨酸 tRNA 激酶 (PSTK) 可提高 HCC 细胞对化疗的敏感性。PSTK 与抑制 HCC 细胞中化疗诱导的铁死亡有关，PSTK 的耗竭导致谷胱甘肽过氧化物酶 4 (GPX4) 失活和谷胱甘肽 (GSH) 代谢中断，因为硒代半胱氨酸和半胱氨酸合成受到抑制，从而增强了靶向化疗治疗诱导的铁死亡。鞣花酸是一种用于治疗乙型肝炎病毒 (HBV) 的药物，被鉴定为 PSTK 的潜在抑制剂，与 Sorafenib 联合应用于体外和体内 HCC 治疗时具有协同作用。
这些结果强调了 PSTK 作为 HCC 细胞靶向治疗耐药性的中介物的关键作用，其作用机制是抑制铁死亡诱导。因此，PSTK 抑制剂可能是克服 HCC 耐药性的理想候选药物。
