Heidari Horestani Mehdi, Schindler Katrin, Baniahmad Aria
Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07740, Jena, Germany.
Cell Commun Signal. 2024 Dec 12;22(1):590. doi: 10.1186/s12964-024-01970-7.
Prostate cancer (PCa) is a public health problem mostly reported in developed countries. The androgen receptor (AR) regulates the development and physiological function of normal prostate as well as the proliferation of cancerous prostate tissue. Treatment with supraphysiological androgen levels (SAL) is used in bipolar androgen therapy and inhibits PCa growth, suggesting SAL induces a tumor suppressive program. It was shown that SAL induces cellular senescence, in PCa cell lines, human tumor samples and in xenografted mouse tumor model.
Transcriptome and ChIP-seq analysis, PCa spheroids, knockdown (KD), co-immunoprecipitation, qRT-PCR, immune detection, in situ histochemistry.
Here we show that LYL1 is upregulated by the clock gene BHLHE40 in both C4-2 and LNCaP cells and mediates SAL-induced cellular senescence. LYL1 is a transcriptional co-factor with oncogenic activity in leukemia. However, analysis of a large cohort of PCa patients shows that LYL1 expression is reduced during PCa development and reduced expression is significantly associated with reduced overall survival. SAL induces the expression of LYL1 through upregulation of BHLHE40. On the other hand, the KD of LYL1 enhances BHLHE40 expression via a negative feedback loop including p27kip1. Regulatory feedback loops were identified by rescue experiments. Functional analysis revealed that KD of BHLHE40 reduces whereas LYL1 KD enhances p27kip1 levels. The KD of p27kip1 suggests that this cell cycle inhibitor is a mediator of cellular senescence by the BHLHE40 - LYL1 regulatory loop. Interestingly, ChIP-seq data revealed recruitment of both AR and BHLHE40 to the LYL1 gene indicating that LYL1 is a novel direct target of both factors. Furthermore, RNA-seq data from C4-2 cells suggests that LYL1 and BHLHE40 encompass a large overlap of genes by SAL suggesting a co-regulatory activity controlled by androgens. In line with this, co-immunoprecipitation suggests LYL1 is in a complex with BHLHE40 and the AR.
Three novel feed-back loops and a novel AR- BHLHE40 / LYL1 -p27kip1 axis has been identified mediating cellular senescence in PCa cells.
前列腺癌（PCa）是一个主要在发达国家报道的公共卫生问题。雄激素受体（AR）调节正常前列腺的发育和生理功能以及癌性前列腺组织的增殖。超生理雄激素水平（SAL）治疗用于双相雄激素疗法并抑制PCa生长，这表明SAL诱导了一种肿瘤抑制程序。研究表明，SAL在PCa细胞系、人肿瘤样本和异种移植小鼠肿瘤模型中均可诱导细胞衰老。
转录组和ChIP-seq分析、PCa球体、敲低（KD）、免疫共沉淀、qRT-PCR、免疫检测、原位组织化学。
在此我们表明，在C4-2和LNCaP细胞中，时钟基因BHLHE40均可上调LYL1的表达，并介导SAL诱导的细胞衰老。LYL1是一种在白血病中具有致癌活性的转录共因子。然而，对大量PCa患者队列的分析表明，LYL1表达在PCa发展过程中降低，且表达降低与总生存期缩短显著相关。SAL通过上调BHLHE40诱导LYL1的表达。另一方面，LYL1的KD通过包括p27kip1的负反馈环增强BHLHE40的表达。通过拯救实验鉴定了调节反馈环。功能分析表明，BHLHE40的KD会降低而LYL1的KD会增强p27kip1水平。p27kip1的KD表明这种细胞周期抑制剂是BHLHE40 - LYL1调节环介导细胞衰老的介质。有趣的是，ChIP-seq数据显示AR和BHLHE40均被招募到LYL1基因，这表明LYL1是这两种因子的一个新的直接靶点。此外，来自C4-2细胞的RNA-seq数据表明，LYL1和BHLHE40在SAL作用下包含大量重叠基因，提示存在由雄激素控制的共调节活性。与此一致的是，免疫共沉淀表明LYL1与BHLHE40和AR形成复合物。
已鉴定出三个新的反馈环和一个新的AR - BHLHE40 / LYL1 - p27kip1轴，它们介导PCa细胞中的细胞衰老。
