A MALDI-MS-based quantitative analytical method for endogenous estrone in human breast cancer cells.
The level of endogenous estrone, one of the three major naturally occurring estrogens, has a significant correlation with the incidence of post-menopausal breast cancer. However, it is challenging to quantitatively monitor it owing to its low abundance. Here, we develop a robust and highly sensitive mass-assisted laser desorption/ionization mass spectrometry (MALDI-MS)-based quantitative platform to identify the absolute quantities of endogenous estrones in a variety of clinical specimens. The one-step modification of endogenous estrone provided good linearity (R(2) > 0.99) and significantly increased the sensitivity of the platform (limit of quantitation: 11 fmol). In addition, we could identify the absolute amount of endogenous estrones in cells of the breast cancer cell line MCF-7 (34 fmol/10(6) cells) by using a deuterated estrone as an internal standard. Finally, by applying the MALDI-MS-based quantitative method to endogenous estrones, we successfully monitored changes in the metabolic expression level of estrones (17.7 fmol/10(6) letrozole-treated cells) in MCF-7 cells resulting from treatment with an aromatase inhibitor. Taken together, these results suggest that this MALDI-MS-based quantitative approach may be a general method for the targeted metabolomics of ketone-containing metabolites, which can reflect clinical conditions and pathogenic mechanisms.
Department of Chemical Engineering, Soongsil University, Seoul 156-743, Korea.
Kyoung-Jin
KJ
Kim
Department of Chemical Engineering, Soongsil University, Seoul 156-743, Korea.
Hee-Jin
HJ
Kim
Department of Chemical Engineering, Soongsil University, Seoul 156-743, Korea.
Han-Gyu
HG
Park
Department of Chemical Engineering, Soongsil University, Seoul 156-743, Korea.
Cheol-Hwan
CH
Hwang
School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea.
Changmin
C
Sung
Division of Bioconvergence Analysis, Korea Basic Science Institute, Chungbuk 363-883, Korea.
Kyoung-Soon
KS
Jang
School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea.
Sung-Hee
SH
Park
School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea.
Byung-Gee
BG
Kim
Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840, Korea.
Yoo-Kyung
YK
Lee
Department of Microbial Engineering, College of Engineering, Konkuk University, Seoul 143-701, Korea.
Yung-Hun
YH
Yang
Department of Chemical Engineering, Soongsil University, Seoul 156-743, Korea.
Jae Hyun
JH
Jeong
Department of Chemical Engineering, Soongsil University, Seoul 156-743, Korea.
Yun-Gon
YG
Kim
D047072:Aromatase Inhibitors / Q000008:administration & dosage; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D004967:Estrogens / Q000302:isolation & purification* / Q000378:metabolism; D004970:Estrone / Q000302:isolation & purification* / Q000378:metabolism; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D055432:Metabolomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D047072:Aromatase Inhibitors; D004967:Estrogens; D004970:Estrone