Lundon D J, Boland A, Prencipe M, Hurley G, O'Neill A, Kay E, Aherne S T, Doolan P, Madden S F, Clynes M, Morrissey C, Fitzpatrick J M, Watson R W
UCD School of Medicine, Conway Institute of Biomedical and Biomolecular Sciences, University College Dublin, Belfield, Dublin, Dublin 4, Ireland.
UCD School of Mathematical Sciences and Insight, University College Dublin, Belfield, Dublin, Dublin 4, Ireland.
BMC Cancer. 2017 Mar 1;17(1):163. doi: 10.1186/s12885-017-3100-4.
Docetaxel based therapy is one of the first line chemotherapeutic agents for the treatment of metastatic castrate-resistant prostate cancer. However, one of the major obstacles in the treatment of these patients is docetaxel-resistance. Defining the mechanisms of resistance so as to inform subsequent treatment options and combinations represents a challenge for clinicians and scientists. Previous work by our group has shown complex changes in pro and anti-apoptotic proteins in the development of resistance to docetaxel. Targeting these changes individually does not significantly impact on the resistant phenotype but understanding the central signalling pathways and transcription factors (TFs) which control these could represent a more appropriate therapeutic targeting approach.
Using a number of docetaxel-resistant sublines of PC-3 cells, we have undertaken a transcriptomic analysis by expression microarray using the Affymetrix Human Gene 1.0 ST Array and in conjunction with bioinformatic analyses undertook to predict dysregulated TFs in docetaxel resistant prostate cancer. The clinical significance of this prediction was ascertained by performing immunohistochemical (IHC) analysis of an identified TF (SRF) in the metastatic sites from men who died of advanced CRPC. Investigation of the functional role of SRF was examined by manipulating SRF using SiRNA in a docetaxel-resistant PC-3 cell line model.
The transcription factors identified include serum response factor (SRF), nuclear factor kappa-B (NFκB), heat shock factor protein 1 (HSF1), testicular receptor 2 & 4 (TR2 &4), vitamin-D and retinoid x receptor (VDR-RXR) and oestrogen-receptor 1 (ESR1), which are predicted to be responsible for the differential gene expression observed in docetaxel-resistance. IHC analysis to quantify nuclear expression of the identified TF SRF correlates with both survival from date of bone metastasis (p = 0.003), survival from androgen independence (p = 0.00002), and overall survival from prostate cancer (p = 0.0044). Functional knockdown of SRF by siRNA demonstrated a reversal of apoptotic resistance to docetaxel treatment in the docetaxel-resistant PC-3 cell line model.
Our results suggest that SRF could aid in treatment stratification of prostate cancer, and may also represent a therapeutic target in the treatment of men afflicted with advanced prostate cancer.
多西他赛为主的治疗方案是转移性去势抵抗性前列腺癌的一线化疗药物之一。然而，这些患者治疗的主要障碍之一是多西他赛耐药。明确耐药机制以便为后续治疗方案和联合用药提供依据，对临床医生和科学家来说是一项挑战。我们团队之前的研究表明，在多西他赛耐药的发展过程中，促凋亡蛋白和抗凋亡蛋白发生了复杂变化。单独针对这些变化对耐药表型的影响并不显著，但了解控制这些变化的核心信号通路和转录因子可能是一种更合适的治疗靶向方法。
我们使用多个PC-3细胞的多西他赛耐药亚系，通过Affymetrix Human Gene 1.0 ST Array表达微阵列进行转录组分析，并结合生物信息学分析来预测多西他赛耐药前列腺癌中失调的转录因子。通过对死于晚期去势抵抗性前列腺癌（CRPC）男性转移部位的一种已鉴定转录因子（血清反应因子，SRF）进行免疫组织化学（IHC）分析，确定该预测的临床意义。在多西他赛耐药的PC-3细胞系模型中，使用小干扰RNA（SiRNA）操纵SRF，研究SRF的功能作用。
鉴定出的转录因子包括血清反应因子（SRF）、核因子κB（NFκB）、热休克因子蛋白1（HSF1）、睾丸受体2和4（TR2和4）、维生素D和视黄酸X受体（VDR-RXR）以及雌激素受体1（ESR1），预计它们导致了多西他赛耐药中观察到的差异基因表达。对已鉴定转录因子SRF的核表达进行定量的IHC分析与骨转移日期后的生存率（p = 0.003）、雄激素非依赖后的生存率（p = 0.00002）以及前列腺癌的总生存率（p = 0.0044）相关。在多西他赛耐药的PC-3细胞系模型中，通过小干扰RNA对SRF进行功能敲低，显示出对多西他赛治疗的凋亡耐药性得到逆转。
我们的结果表明，SRF有助于前列腺癌的治疗分层，也可能是晚期前列腺癌患者治疗的一个靶点。
