Obesity, an established risk factor for breast and other cancers, is associated with systemic inflammation and increased visceral adipose tissue. Adipose tissue is a normal constituent of the breast; however, the role of breast adipose tissue in breast cancer development, especially in the context of obesity, has not been addressed before. There is no information on the lipid composition of different fat depots in the body, especially in the context of obesity, and even less among obese tumor hosts. The study of the lipid composition of breast adipose tissue in diet-induced obese (DIO) tumor-bearing and normal mice and its impact in breast cancer progression is novel and has not been previously examined. New profiling methods employing shotgun lipidomics, a technique employed in mass spectrometric analysis using the direct loading of crude lipid extracts into an electrospray ionization source for intrasource separation and identification of numerous lipids, allow for extensive cellular lipid profiles of different tissues being accrued with relative ease. We studied the lipidomic profiles of the breast adipose tissue in lean and DIO normal and tumor bearing mice. Lipidomics analyses were performed using an electrospray triple quadrupole mass spectrometer (TSQ quantum Access Max) and class specific parent-ion or neutral loss scan in positive and negative ion mode with appropriate collision energy. The ratiometic quantification of lipids was done using class specific lipid standards. The phospholipid classes quantified were phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE). Our results for the PC class reveal an association between the total carbon chain of the lipids and the lipid concentrations based on four conditions: lean control, obese control, lean tumor bearers, and obese tumor bearers. The highest total carbon chain length is associated with the obese tumor condition. The next highest total carbon chain length is associated with lean tumor condition. This demonstrates that both the presence of the tumor as well as obesity play a role in contributing to a higher number of total carbons in the lipid chains. The other lipid classes analyzed express similar patterns from the data gathered when compared to the PC lipid class. Characterizing a particular lipid signature relevant to breast cancer and obesity may allow its targeting with therapeutic purposes.
Citation Format: Osvaldo Perez, Michael Margolis, Ana M. Santander, Mitchell Martinez, Sanjoy Bhattacharya, Marta Torroella-Kouri. Breast cancer and obesity impact the lipid composition of breast adipose tissue: a preliminary study using shotgun lipidomics. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3496. doi:10.1158/1538-7445.AM2014-3496