Centers of Excellence in Environmental Toxicology and Cancer Pharmacology, Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
J Steroid Biochem Mol Biol. 2013 Nov;138:281-9. doi: 10.1016/j.jsbmb.2013.06.014. Epub 2013 Jul 10.
Prostate cancer is the most frequently diagnosed form of cancer in males in the United States. The disease is androgen driven and the use of orchiectomy or chemical castration, known as androgen deprivation therapy (ADT) has been employed for the treatment of advanced prostate cancer for over 70 years. Agents such as GnRH agonists and non-steroidal androgen receptor antagonists are routinely used in the clinic, but eventually relapse occurs due to the emergence of castration-resistant prostate cancer. With the appreciation that androgen signaling still persists in these patients and the development of new therapies such as abiraterone and enzalutamide that further suppresses androgen synthesis or signaling, there is a renewed need for sensitive and specific methods to quantify androgen precursor and metabolite levels to assess drug efficacy. We describe the development, validation and application of a stable isotope dilution liquid chromatography electrospray ionization selected reaction monitoring mass spectrometry (SID-LC/ESI/SRM/MS) method for quantification of serum keto-androgens and their sulfate and glucuronide conjugates using Girard-T oxime derivatives. The method is robust down to 0.2-4pg on column, depending on the androgen metabolite quantified, and can also quantify dehydroepiandrosterone sulfate (DHEA-S) in only 1μL of serum. The clinical utility of this method was demonstrated by analyzing serum androgens from patients enrolled in a clinical trial assessing combinations of pharmacological agents to maximally suppress gonadal and adrenal androgens (Targeted Androgen Pathway Suppression, TAPS clinical trial). The method was validated by correlating the results obtained with a hydroxylamine derivatization procedure coupled with tandem mass spectrometry using selected reaction monitoring that was conducted in an independent laboratory.
前列腺癌是美国男性最常见的癌症类型。这种疾病是雄激素驱动的，使用睾丸切除术或化学去势，即雄激素剥夺疗法（ADT），已经用于治疗晚期前列腺癌超过 70 年。促性腺激素释放激素激动剂和非甾体雄激素受体拮抗剂等药物通常在临床上使用，但由于出现去势抵抗性前列腺癌，最终会复发。由于认识到这些患者的雄激素信号仍然存在，以及阿比特龙和恩扎鲁胺等新疗法的发展，这些药物进一步抑制雄激素合成或信号，因此需要更敏感和特异的方法来定量雄激素前体和代谢物水平，以评估药物疗效。我们描述了一种稳定同位素稀释液相色谱-电喷雾电离-选择反应监测-质谱（SID-LC/ESI/SRM/MS）方法的开发、验证和应用，该方法使用 Girard-T 肟衍生物定量血清中的酮雄激素及其硫酸盐和葡萄糖醛酸缀合物。该方法的灵敏度高达 0.2-4pg 柱上，具体取决于定量的雄激素代谢物，并且仅用 1μL 血清即可定量脱氢表雄酮硫酸盐（DHEA-S）。通过分析参加评估药物联合使用以最大程度抑制性腺和肾上腺雄激素的临床试验（靶向雄激素途径抑制，TAPS 临床试验）的患者的血清雄激素，证明了该方法的临床实用性。该方法通过与在独立实验室进行的串联质谱法中使用选择反应监测的羟胺衍生化程序获得的结果进行相关验证。
