分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: One of the major challenges in prostate cancer therapy remains the development of effective treatments for castration-resistant prostate cancer (CRPC), as the underlying mechanisms for its progression remain elusive. Previous studies showed that androgen receptor (AR) is crucially involved in regulation of metabolism in prostate cancer (PCa) cells throughout the transition from early stage, androgen-sensitive PCa to androgen-independent CRPC. AR achieves such metabolic rewiring directively either via its transcriptional activity or via interactions with AMP-activated protein kinase (AMPK). However, due to the heterogeneous expression and activity status of AR in PCa cells, it remains a challenge to investigate the links between AR status and metabolic alterations. To this end, we compared the proteomes of three pairs of androgen-sensitive (AS) and androgen-independent (AI) PCa cell lines, namely, PC3-AR(+)/PC3, 22Rv1/Du145, and LNCaP/C42B, using an iTRAQ labeling approach. Our results revealed that most of the differentially expressed proteins between each pair function in metabolism, indicating a metabolic shift between AS and AT cells, as further validated by multiple reaction monitoring (MRM)-based quantification of nucleotides and relative comparison of fatty acids between these cell lines. Furthermore, increased adenylate kinase isoenzyme 1 (AK1) in AS relative to AT cells may result in activation of AMPK, representing a major regulatory factor involved in the observed metabolic shift in PCa cells.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-11
摘要: A comprehensive approach that can identify and quantify selenium (Se) in seleno-proteins in Se-enriched yeast was developed. The Se-containing compounds in Se-enriched yeast were first extracted and then the fraction of Se-containing proteins in the supernatant was analyzed by 2-dimensional electrophoresis (2-DE) and synchrotron radiation X-ray fluorescence (SR-XRF). The detection limit (DL) of SR-XRF analysis for Se quantification in Se-containing proteins after 2-DE separation was calculated to be 0.20 mu g g(-1), which is suitable for Se quantification in the Se-containing spots present on the 2-D gel. After being scanned by SR-XRF, only spots with a mean Se content exceeding twice the DL of SR-XRF were considered to be seleno-proteins. In this way, a total of 157 Se-containing spots in the gel were visually distinguished. Se contents in all the Se-containing proteins of different molecular weights were quantified. The total Se content on the 2-D gel was calculated to be 126.56 mu g g(-1), which covered most of the seleno-proteins on the 2-D gel.