Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA.
Pathology and Laboratory Medicine, University of Kentucky, Lexington, Kentucky, USA.
J Biol Chem. 2022 Jul;298(7):102123. doi: 10.1016/j.jbc.2022.102123. Epub 2022 Jun 10.
High levels of redox enzymes have been commonly observed in various types of human cancer, although whether and how the enzymes contribute to cancer malignancy and therapeutic resistance have yet to be understood. Peroxiredoxin IV (Prx4) is an antioxidant with bona fide peroxidase and molecular chaperone functions. Here, we report that Prx4 is highly expressed in prostate cancer patient specimens, as well as established prostate cancer cell lines, and that its levels can be further stimulated through the activation of androgen receptor signaling. We used lentivirus-mediated shRNA knockdown and CRISPR-Cas9 based KO techniques to establish Prx4-depleted prostate cancer cells, which showed delayed cell cycle progression, reduced rate of cell proliferation, migration, and invasion compared to control cells. In addition, we used proteome profiler phosphokinase arrays to identify signaling changes in Prx4-depleted cells; we found that loss of Prx4 results in insufficient phosphorylation of both Akt and its downstream kinase GSK3α/β. Moreover, we demonstrate that Prx4-depleted cells are more sensitive to ionizing radiation as they display compromised ability to scavenge reactive oxygen species and increased accumulation of DNA damage. In mouse xenograft models, we show depletion of Prx4 leads to significant suppression of tumor growth, and tumors formed by Prx4-depleted cells respond more effectively to radiation therapy. Our findings suggest that increased levels of Prx4 contribute to the malignancy and radioresistance of prostate cancer through the activation of Akt/GSK3 signaling pathways. Therefore, strategies targeting Prx4 may be utilized to potentially inhibit tumor growth and overcome radioresistance in prostate cancer.
高水平的氧化还原酶在各种类型的人类癌症中普遍存在，尽管这些酶是否以及如何促进癌症恶性和治疗耐药性尚未被理解。过氧化物酶 4（Prx4）是一种具有真正过氧化物酶和分子伴侣功能的抗氧化剂。在这里，我们报告 Prx4 在前列腺癌患者标本以及已建立的前列腺癌细胞系中高度表达，并且其水平可以通过激活雄激素受体信号进一步刺激。我们使用慢病毒介导的 shRNA 敲低和基于 CRISPR-Cas9 的 KO 技术建立了 Prx4 缺失的前列腺癌细胞，与对照细胞相比，这些细胞的细胞周期进程延迟，增殖、迁移和侵袭率降低。此外，我们使用蛋白质组印迹激酶阵列鉴定了 Prx4 缺失细胞中的信号变化；我们发现 Prx4 的缺失导致 Akt 及其下游激酶 GSK3α/β 的磷酸化不足。此外，我们证明 Prx4 缺失的细胞对电离辐射更敏感，因为它们清除活性氧的能力受损，并且 DNA 损伤的积累增加。在小鼠异种移植模型中，我们表明 Prx4 的缺失导致肿瘤生长显著抑制，并且由 Prx4 缺失细胞形成的肿瘤对放射治疗更有效。我们的研究结果表明，Prx4 水平的升高通过激活 Akt/GSK3 信号通路促进前列腺癌的恶性和放射抗性。因此，靶向 Prx4 的策略可能用于潜在地抑制前列腺癌的肿瘤生长并克服放射抗性。
