Impaired AKT signaling and lung tumorigenesis by PIERCE1 ablation in KRAS-mutant non-small cell lung cancer

KRAS-mutant non-small cell lung cancer (NSCLC) is one of the main subtypes across lung cancers. Despite the enormous studies on KRAS-mutant NSCLC, new therapeutic targets need to be identified because current therapies are insufficient. Here we show the tumor promoting function of PIERCE1 in the KRAS-mutant NSCLC. Mechanistically, PIERCE1 depletion inhibits cell growth and AKT phosphorylation (pAKT) at S473, particularly in KRAS-mutant lung cancer. Analyses of AKT-related genes show that PIERCE1 negatively regulates gene expression of AKT suppressor TRIB3 through CHOP pathway. Correspondingly, four independent in vivo approaches in lung cancer mouse models related to KRAS mutations reveal the tumor suppressive effect of PIERCE1 depletion suggesting its therapeutic potential. Tissue microarray of human lung cancer showed that PIERCE1 is expressed in 83% of lung cancers and is linked to pAKT expression. This illustrates how PIERCE1 depletion acts as a novel therapeutics against KRAS-mutant NSCLC. The mRNA levels were measured for two biological replicates for each condition: A549 cells transfected with one of three different sequences of siPIERCE1 (siP1 #1, siP1 #2, and siP1 #3) or control (siControl).

KRAS突变型非小细胞肺癌（non-small cell lung cancer, NSCLC）是肺癌主要亚型之一。尽管针对KRAS突变型非小细胞肺癌已有大量研究，但由于现有治疗手段存在局限，仍需挖掘全新的治疗靶点。本研究揭示了PIERCE1在KRAS突变型非小细胞肺癌中的促肿瘤功能。机制层面分析显示，敲低PIERCE1可抑制细胞增殖，并降低KRAS突变型肺癌细胞中丝氨酸473位点的AKT磷酸化水平（pAKT）。对AKT相关基因的分析表明，PIERCE1可通过CHOP通路负调控AKT抑制因子TRIB3的基因表达。相应地，在4种独立的KRAS突变相关肺癌小鼠模型体内实验中，敲低PIERCE1均展现出抑瘤效果，提示其具备治疗潜力。人类肺癌组织芯片检测结果显示，83%的肺癌组织中均有PIERCE1表达，且其表达与pAKT表达相关。上述结果表明，敲低PIERCE1可作为KRAS突变型非小细胞肺癌的新型治疗策略。本实验针对每种处理条件设置2次生物学重复以检测mRNA水平：将A549细胞转染3种不同序列的siPIERCE1（siP1 #1、siP1 #2及siP1 #3）或阴性对照siControl。