Yang Qiaohong, Gupta Romi
Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA.
Oncotarget. 2017 Dec 23;9(5):5906-5918. doi: 10.18632/oncotarget.23643. eCollection 2018 Jan 19.
UV is one of the major causes of DNA damage induced apoptosis. However, cancer cells adopt alternative mechanisms to evade UV-induced apoptosis. To identify factors that protect cancer cells from UV-induced apoptosis, we performed a genome wide short-hairpin RNA (shRNA) screen, which identified Zinc finger protein 598 (ZNF598) as a key regulator of UV-induced apoptosis. Here, we show that UV irradiation transcriptionally upregulates ZNF598 expression. Additionally, ZNF598 knockdown in cancer cells inhibited UV-induced apoptosis. In our study, we observe that ELK1 mRNA level as well as phosphorylated ELK1 levels was up regulated upon UV irradiation, which was necessary for UV irradiation induced upregulation of ZNF598. Cells expressing ELK1 shRNA were also resistant to UV-induced apoptosis, and phenocopy ZNF598 knockdown. Upon further investigation, we found that ZNF598 knockdown inhibits UV-induced apoptotic gene expression, which matches with decrease in percentage of annexin V positive cell. Similarly, ectopic expression of ZNF598 promoted apoptotic gene expression and also increased annexin V positive cells. Collectively, these results demonstrate that ZNF598 is a UV irradiation regulated gene and its loss results in resistance to UV-induced apoptosis.
紫外线是导致DNA损伤诱导细胞凋亡的主要原因之一。然而，癌细胞采用其他机制来逃避紫外线诱导的细胞凋亡。为了确定保护癌细胞免受紫外线诱导细胞凋亡的因素，我们进行了全基因组短发夹RNA（shRNA）筛选，该筛选确定锌指蛋白598（ZNF598）是紫外线诱导细胞凋亡的关键调节因子。在此，我们表明紫外线照射在转录水平上上调ZNF598的表达。此外，在癌细胞中敲低ZNF598可抑制紫外线诱导的细胞凋亡。在我们的研究中，我们观察到紫外线照射后ELK1 mRNA水平以及磷酸化ELK1水平上调，这是紫外线照射诱导ZNF598上调所必需的。表达ELK1 shRNA的细胞也对紫外线诱导的细胞凋亡具有抗性，并且与敲低ZNF598表现出相似的表型。进一步研究发现，敲低ZNF598可抑制紫外线诱导的凋亡基因表达，这与膜联蛋白V阳性细胞百分比的降低相匹配。同样，异位表达ZNF598可促进凋亡基因表达，并增加膜联蛋白V阳性细胞。总的来说，这些结果表明ZNF598是一个受紫外线照射调节的基因，其缺失导致对紫外线诱导细胞凋亡的抗性。
