Michael Stern Laboratory for Polycystic Kidney Disease, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia.
Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Westmead, NSW 2145, Australia.
Int J Mol Sci. 2021 Sep 29;22(19):10512. doi: 10.3390/ijms221910512.
DNA-dependent protein kinase (DNA-PK) is a serine/threonine protein involved in DNA damage response (DDR) signaling that may mediate kidney cyst growth in autosomal dominant polycystic kidney disease (ADPKD) due to its pleiotropic effects on proliferation and survival. To test this hypothesis, the expression of DNA-PK in human ADPKD and the in vitro effects of DNA-PK inhibition in a three-dimensional model of Madin-Darby Canine Kidney (MDCK) cyst growth and human ADPKD cells were assessed. In human ADPKD, the mRNA expression for all three subunits of the DNA-PK complex was increased, and using immunohistochemistry, the catalytic subunit (DNA-PKcs) was detected in the cyst lining epithelia of human ADPKD, in a focal manner. In vitro, NU7441 (a DNA-PK kinase inhibitor) reduced MDCK cyst growth by up to 52% after long-term treatment over 6-12 days. Although human ADPKD cell lines (WT9-7/WT9-12) did not exhibit synthetic lethality in response to DNA-PK kinase inhibition compared to normal human kidney cells (HK-2), the combination of low-dose NU7441 enhanced the anti-proliferative effects of sirolimus in WT9-7 and WT9-12 cells by 17 ± 10% and 11 ± 7%, respectively. In conclusion, these preliminary data suggest that DNA-PK mediates kidney cyst growth in vivo without a synthetically lethal interaction, conferring cell-specificity in human ADPKD cells. NU7441 enhanced the anti-proliferative effects of rapamycin complex 1 inhibitors, but the effect was modest.
DNA 依赖性蛋白激酶（DNA-PK）是一种丝氨酸/苏氨酸蛋白，参与 DNA 损伤反应（DDR）信号转导，由于其对增殖和存活的多效性影响，可能介导常染色体显性多囊肾病（ADPKD）中的肾脏囊肿生长。为了验证这一假设，评估了 DNA-PK 在人 ADPKD 中的表达以及 DNA-PK 抑制在三维 Madin-Darby 犬肾（MDCK）囊肿生长和人 ADPKD 细胞模型中的体外作用。在人 ADPKD 中，DNA-PK 复合物的所有三个亚基的 mRNA 表达均增加，并且使用免疫组织化学，在人 ADPKD 的囊肿衬里上皮中检测到催化亚基（DNA-PKcs）呈局灶性。在体外，NU7441（一种 DNA-PK 激酶抑制剂）在长期治疗 6-12 天后，可使 MDCK 囊肿生长减少多达 52%。尽管与正常人类肾脏细胞（HK-2）相比，人 ADPKD 细胞系（WT9-7/WT9-12）在 DNA-PK 激酶抑制作用下未表现出合成致死性，但低剂量 NU7441 增强了 sirolimus 在 WT9-7 和 WT9-12 细胞中的抗增殖作用，分别为 17±10%和 11±7%。总之，这些初步数据表明，DNA-PK 在体内介导肾脏囊肿生长，而没有合成致死性相互作用，赋予了人 ADPKD 细胞的细胞特异性。NU7441 增强了雷帕霉素复合物 1 抑制剂的抗增殖作用，但作用适度。
