Transcriptional changes by RBN-2397 treatment and FRA1 knockdown in NCI-H1975 cells

PARP7 inhibitors reduce tumor growth in a cell-autonomous manner and by enhancing immune recognition through restoring nucleic acid (NA)-sensing-dependent innate immune signaling. However, the molecular targets of PARP7-mediated ADP-ribosylation, regulating cell survival and innate immune signaling, remained elusive. Here, we identified PARP7 as a nuclear and cysteine-specific mono-ART that ADP-ribosylates proteins critical for regulating gene expression, such as the AP-1 transcription factor FRA1. Upon PARP7 inhibition the loss of FRA1 ADP-ribosylation increased FRA1 degradation in a PSMC3 and proteasomal-dependent manner. To further investigate how FRA1 promotes cell survival, we investigated transcriptional changes after RBN-2397 treatment and FRA1 knockdown in the PARP7 inhibitor sensitive cell line NCI-H1975 by RNA sequencing. RNA sequencing of NCI-H1975 cells after RBN-2397 treatment (6h) or FRA1 knockdown (48h)

聚ADP核糖聚合酶7（PARP7）抑制剂可通过细胞自主性方式，以及恢复核酸（NA）感知依赖的先天免疫信号通路以增强免疫识别，从而抑制肿瘤生长。然而，PARP7介导的ADP核糖基化（ADP-ribosylation）的分子靶点——其调控细胞存活与先天免疫信号通路——仍未明确。本研究鉴定出PARP7是一种定位于细胞核、具有半胱氨酸特异性的单ADP核糖基转移酶（mono-ART），可对调控基因表达的关键蛋白（如AP-1转录因子FRA1）进行ADP核糖基化修饰。当PARP7被抑制后，FRA1的ADP核糖基化修饰缺失会以PSMC3依赖、蛋白酶体介导的方式加速FRA1降解。为进一步探究FRA1促进细胞存活的具体机制，我们在PARP7抑制剂敏感细胞系NCI-H1975中，通过RNA测序分析了RBN-2397处理或FRA1敲低后的转录组变化，具体为对经RBN-2397处理6小时或FRA1敲低48小时的NCI-H1975细胞进行RNA测序。