Supplementary Material for: Inhibition of Heat Shock Factor 1 Enhances Repressive Molecular Mechanisms on the <b><i>POMC</i></b> Promoter

<b><i>Background:</i></b> Cushing’s disease (CD) is caused by adrenocorticotropic hormone (ACTH)-secreting pituitary tumours. They express high levels of heat shock protein 90 and heat shock factor 1 (HSF1) in comparison to the normal tissue counterpart, indicating activated cellular stress. <b><i>Aims:</i></b> Our objectives were: (1) to correlate HSF1 expression with clinical features and hormonal/radiological findings of CD, and (2) to investigate the effects of HSF1 inhibition as a target for CD treatment. <b><i>Patients/Methods:</i></b> We examined the expression of total and pSer³²⁶HSF1 (marker for its transcriptional activation) by Western blot on eight human CD tumours and compared to the HSF1 status of normal pituitary. We screened a cohort of 45 patients with CD for HSF1 by immunohistochemistry and correlated the HSF1 immunoreactivity score with the available clinical data. We evaluated the effects of HSF1 silencing with RNA interference and the HSF1 inhibitor KRIBB11 in AtT-20 cells and four primary cultures of human corticotroph tumours. <b><i>Results:</i></b> We show that HSF1 protein is highly expressed and transcriptionally active in CD tumours in comparison to normal pituitary. The immunoreactivity score for HSF1 did not correlate with the typical clinical features of the disease. HSF1 inhibition reduced proopiomelanocortin (<i>Pomc</i>) transcription in AtT-20 cells. The HSF1 inhibitor KRIBB11 suppressed ACTH synthesis from 75% of human CD tumours in primary cell culture. This inhibitory action on <i>Pomc</i> transcription was mediated by increased glucocorticoid receptor and suppressed Nurr77/Nurr1 and AP-1 transcriptional activities. <b><i>Conclusions:</i></b> These data show that HSF1 regulates <i>POMC</i> transcription. Pharmacological targeting of HSF1 may be a promising treatment option for the control of excess ACTH secretion in CD.

<b><i>背景：</i></b> 库欣病（Cushing’s disease, CD）由分泌促肾上腺皮质激素（adrenocorticotropic hormone, ACTH）的垂体腺瘤引发。与正常垂体组织相比，此类腺瘤高表达热休克蛋白90（heat shock protein 90）与热休克因子1（heat shock factor 1, HSF1），提示细胞应激处于激活状态。<b><i>研究目的：</i></b> 本研究的目标为：（1）明确HSF1表达与库欣病的临床特征、激素及影像学检查结果的相关性；（2）探究以HSF1为靶点进行库欣病治疗的效果。<b><i>研究对象与方法：</i></b> 本研究通过免疫印迹（Western blot）检测了8例人库欣病腺瘤组织中总HSF1与磷酸化Ser³²⁶HSF1（pSer³²⁶HSF1，其转录激活标志物）的表达水平，并以正常垂体组织的HSF1表达情况作为对照。通过免疫组化（immunohistochemistry）检测了45例库欣病患者队列的HSF1表达情况，并将HSF1免疫反应评分与可获取的临床数据进行关联分析。此外，本研究利用RNA干扰（RNA interference, RNAi）技术与HSF1抑制剂KRIBB11，分别在AtT-20细胞及4例人促肾上腺皮质激素瘤原代培养细胞中评估了HSF1抑制的作用效果。<b><i>研究结果：</i></b> 本研究证实，与正常垂体组织相比，库欣病腺瘤组织中HSF1蛋白表达水平显著升高且转录活性增强。HSF1免疫反应评分与该病典型临床特征无相关性。在AtT-20细胞中，HSF1抑制可降低阿黑皮素原（proopiomelanocortin, Pomc）的转录水平。HSF1抑制剂KRIBB11可在原代细胞培养中抑制75%的人库欣病腺瘤组织的ACTH合成。该对Pomc转录的抑制作用，是通过增强糖皮质激素受体（glucocorticoid receptor）活性、抑制Nurr77/Nurr1与激活蛋白1（activator protein 1, AP-1）的转录活性实现的。<b><i>研究结论：</i></b> 上述数据表明，HSF1可调控POMC基因的转录。以HSF1为靶点进行药物干预，有望成为控制库欣病患者过量ACTH分泌的潜在治疗方案。

搜集汇总

背景与挑战

背景概述

该数据集是Cushing's disease（库欣病）研究的补充材料，聚焦于热休克因子1（HSF1）在调控POMC启动子中的作用。它包含实验数据（如Western blot、免疫组化和细胞培养结果），展示了HSF1抑制如何减少ACTH合成，并探讨了其作为潜在治疗靶点的可能性。数据集以PDF文件形式提供，发布于2019年，适用于神经内分泌学和医学研究领域。