Kim Yunlim, Park Sang Eun, Moon Jeong-Weon, Kim Bong-Min, Kim Ha-Gyeong, Jeong In Gab, Yoo Sangjun, Ahn Jae Beom, You Dalsan, Pak Jhang Ho, Kim Sujong, Hwang Jung Jin, Kim Choung-Soo
Department of Urology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
Institute for Innovative Cancer Research, Asan Medical Center, Seoul, Korea.
Prostate. 2017 Jul;77(10):1128-1136. doi: 10.1002/pros.23370. Epub 2017 May 30.
Androgen and androgen receptor (AR) play essential roles in the development and maintenance of prostate cancer. The recently identified AR splice variants (AR-Vs) have been considered as a plausible mechanism for the primary resistance against androgen deprivation therapy (ADT) in castration-resistant prostate cancer (CRPC). Sodium meta-arsenite (NaAsO ; KML001; Kominox), a trivalent arsenical, is an orally bioavailable and water soluble, which is currently in phase I/II clinical trials for the treatment of prostate cancer. It has a potent anti-cancer effect on prostate cancer cells and xenografts. The aim of this study was to examine the effect of NaAsO on AR signaling in LNCaP and 22Rv1 CRPC cells.
We used hormone-sensitive LNCaP cells, hormone-insensitive 22Rv1 cells, and CRPC patient-derived primary cells. We analyzed anti-cancer effect of NaAsO using real-time quantitative reverse transcription-PCR, Western blotting, immunofluorescence staining and CellTiter Glo® luminescent assay. Statistical evaluation of the results was performed by one-way ANOVA.
NaAsO significantly reduced the translocation of AR and AR-Vs to the nucleus as well as their level in LNCaP and 22Rv1 cells. Besides, the level of the prostate-specific antigen (PSA), downstream target gene of AR, was also decreased. This compound was also an effective modulator of AKT-dependent NF-κB activation which regulates AR. NaAsO significantly inhibited phosphorylation of AKT and expression and nuclear translocation of NF-κB. We then investigated the effect of NaAsO on AR stabilization. NaAsO promoted HSP90 acetylation by down-regulating HDAC6, which reduces the stability of AR in prostate cancer cells.
Here, we show that NaAsO disrupts AR signaling at multiple levels by affecting AR expression, stability, and degradation in primary tumor cell cultures from prostate cancer patients as well as CRPC cell lines. These results suggest that NaAsO could be a novel therapeutics for prostate cancer.
雄激素和雄激素受体（AR）在前列腺癌的发生和维持中起着至关重要的作用。最近发现的AR剪接变体（AR-Vs）被认为是去势抵抗性前列腺癌（CRPC）对雄激素剥夺治疗（ADT）产生原发性抵抗的一种可能机制。偏亚砷酸钠（NaAsO₂；KML001；Kominox），一种三价砷化合物，口服生物利用度高且水溶性好，目前正处于治疗前列腺癌的I/II期临床试验阶段。它对前列腺癌细胞和异种移植瘤具有强大的抗癌作用。本研究的目的是检测NaAsO₂对LNCaP和22Rv1 CRPC细胞中AR信号通路的影响。
我们使用了激素敏感的LNCaP细胞、激素不敏感的22Rv1细胞以及CRPC患者来源的原代细胞。我们通过实时定量逆转录PCR、蛋白质印迹、免疫荧光染色和CellTiter Glo®发光测定法分析了NaAsO₂的抗癌作用。结果的统计评估采用单因素方差分析。
NaAsO₂显著降低了AR和AR-Vs向细胞核的转位以及它们在LNCaP和22Rv1细胞中的水平。此外，AR的下游靶基因前列腺特异性抗原（PSA）的水平也降低了。该化合物还是调节AR的AKT依赖性NF-κB激活的有效调节剂。NaAsO₂显著抑制AKT的磷酸化以及NF-κB的表达和核转位。然后我们研究了NaAsO₂对AR稳定性的影响。NaAsO₂通过下调HDAC6促进HSP90乙酰化，从而降低前列腺癌细胞中AR的稳定性。
在此，我们表明NaAsO₂通过影响前列腺癌患者原代肿瘤细胞培养物以及CRPC细胞系中AR的表达、稳定性和降解，在多个水平上破坏AR信号通路。这些结果表明NaAsO₂可能是一种新型的前列腺癌治疗药物。
