Zhang Xiaoli, Ma Yiming, Ma Jianhui, Yang Lan, Song Qingzhi, Wang Hongying, Lv Guoqing
Department of Gastrointestinal Surgery, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China.
State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China.
Front Oncol. 2022 Jun 3;12:913669. doi: 10.3389/fonc.2022.913669. eCollection 2022.
Despite the effectiveness of chemotherapy and targeted therapy for colorectal cancer, drug resistance drives therapy failure and tumor relapse. Increasing evidence has suggested that cancer cells can enter a reversible drug-tolerant persister state to survive chemotherapy or targeted agents. However, the traits and treatable vulnerabilities of anti-colorectal cancer drug-tolerant persister cells is not yet known.
In this study, we established 5-fluorouracil and AZ628-tolerant persister cell models in two colorectal cancer cell lines, namely HCT116 and SW620, and revealed the characteristics of colorectal cancer persister cells by cell viability assay and flow cytometry. We investigated the efficacy and mechanism of ferroptosis inducers RSL3 and FIN56 on persister cells, which are glutathione peroxidase 4 inhibitors. In the xenograft mouse model, we further evaluated the inhibitory effect of RSL3 on tumor regrowth.
Colorectal cancer persister cells, which were enriched in the residual cancer cell population, exhibited reduced drug sensitivity, were largely quiescent and expressed high levels of stem cell-related genes and mesenchymal markers but not epithelial markers. The persister cells were more sensitive and underwent ferroptosis induced by glutathione peroxidase 4 inhibitors. Mechanistically, glutathione peroxidase 4 and ferrous iron, which are pivotal ferroptosis regulators, were upregulated in residual cells or tumors, and were hence potential therapeutic targets of persister cells. In the xenograft model, we confirmed that inhibition of glutathione peroxidase 4 restrained tumor regrowth after discontinuation of anti-cancer drug treatment. Moreover, biopsies obtained from patients with colorectal cancer undergoing neoadjuvant chemoradiotherapy revealed upregulated glutathione peroxidase 4 and ferritin heavy chain 1. High glutathione peroxidase 4 expression correlates with a worse prognosis in colorectal cancer patients.
Our work reveals that the upregulated glutathione peroxidase 4 and ferrous iron in anti-colorectal cancer drug-tolerant persister cells were potential therapeutic targets. Glutathione peroxidase 4 inhibition combined with chemotherapy or targeted therapy may be a promising therapy for colorectal cancer.
尽管化疗和靶向治疗对结直肠癌有效，但耐药性会导致治疗失败和肿瘤复发。越来越多的证据表明，癌细胞可以进入一种可逆的耐药性持久细胞状态，以在化疗或靶向药物治疗中存活下来。然而，抗结直肠癌耐药性持久细胞的特征和可治疗的脆弱性尚不清楚。
在本研究中，我们在两种结直肠癌细胞系HCT116和SW620中建立了5-氟尿嘧啶和AZ628耐药性持久细胞模型，并通过细胞活力测定和流式细胞术揭示了结直肠癌持久细胞的特征。我们研究了铁死亡诱导剂RSL3和FIN56（它们是谷胱甘肽过氧化物酶4抑制剂）对持久细胞的疗效和作用机制。在异种移植小鼠模型中，我们进一步评估了RSL3对肿瘤再生长的抑制作用。
富集于残留癌细胞群体中的结直肠癌持久细胞表现出药物敏感性降低，大多处于静止状态，高表达干细胞相关基因和间充质标志物，但不表达上皮标志物。持久细胞对谷胱甘肽过氧化物酶4抑制剂诱导的铁死亡更敏感，并会发生铁死亡。从机制上讲，作为关键铁死亡调节因子的谷胱甘肽过氧化物酶4和亚铁离子在残留细胞或肿瘤中上调，因此是持久细胞的潜在治疗靶点。在异种移植模型中，我们证实抑制谷胱甘肽过氧化物酶4可抑制抗癌药物治疗停止后的肿瘤再生长。此外，对接受新辅助放化疗的结直肠癌患者进行的活检显示，谷胱甘肽过氧化物酶4和铁蛋白重链1上调。谷胱甘肽过氧化物酶4高表达与结直肠癌患者预后较差相关。
我们的研究表明，抗结直肠癌耐药性持久细胞中上调的谷胱甘肽过氧化物酶4和亚铁离子是潜在的治疗靶点。抑制谷胱甘肽过氧化物酶4联合化疗或靶向治疗可能是一种有前景的结直肠癌治疗方法。
