A MALDI-MS-based quantitative analytical method for endogenous estrone in human breast cancer cells

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Endogenous estrone levels correlate with post-menopausal breast cancer incidence.
• Quantifying low-abundance estrone in clinical specimens presents a significant challenge.

Purpose of the Study:

• To develop a robust and highly sensitive mass-assisted laser desorption/ionization mass spectrometry (MALDI-MS) platform for absolute estrone quantification.
• To establish a method for monitoring estrone levels in various clinical specimens, including cell lines.

Main Methods:

• Development of a one-step modification protocol for estrone to enhance MALDI-MS sensitivity.
• Utilized a deuterated estrone internal standard for accurate quantification in MCF-7 breast cancer cells.
• Applied the MALDI-MS platform to monitor estrone metabolic changes in response to aromatase inhibitor treatment.

Main Results:

• The developed platform demonstrated excellent linearity (R(2) > 0.99) and high sensitivity (limit of quantitation: 11 fmol).
• Absolute estrone quantities were successfully determined in MCF-7 cells (34 fmol/10(6) cells).
• Changes in estrone metabolic expression were monitored in treated MCF-7 cells (17.7 fmol/10(6) cells).

Conclusions:

• The MALDI-MS-based quantitative approach offers a sensitive and robust method for estrone measurement.
• This technique may serve as a general platform for targeted metabolomics of ketone-containing metabolites.
• The method has potential applications in reflecting clinical conditions and understanding breast cancer pathogenesis.