Phospholipid makeup of the breast adipose tissue is impacted by obesity and mammary cancer in the mouse: Results of a pilot study

Abstract

Obesity, an established risk factor for breast cancer (BC), is associated with systemic inflammation. The breast contains adipose tissue (bAT), yet whether it plays a role in BC progression in obese females is being intensively studied. There is scarce knowledge on the lipid composition of bAT in health and disease. The purpose of this pilot study was: 1) to determine whether obesity and BC are associated with inflammatory changes in bAT 2) to analyze for the first time the lipid profile of bAT in obese and lean mammary tumor-bearing and normal mice. Syngeneic E0771 mammary tumor cells were implanted into the mammary fat pad of lean and diet-induced obese C57BL/6 mice. BATs were analyzed four weeks after tumor cell inoculation by immunohistochemistry and mass spectrometry. Phospholipids were identified and subjected to ratiometric quantification using a TSQ Quantum Access Max triple quadrupole mass spectrometer utilizing precursor ion scan or neutral ion loss scan employing appropriate class specific lipid standards in a two step quantification process. Four main classes of phospholipids were analyzed: phosphatidylcholines phosphatidylserines, phosphatidylethanolamines and phosphatidylinositols. Our results showed that bAT in obese (normal and tumor-bearing) mice contained hypertrophic adipocytes compared with their corresponding samples in lean mice; higher numbers of macrophages and crown-like structures were observed in obese tumor bearers compared to obese normal mice. BAT from normal obese mice revealed higher concentrations of phosphatidylethanolamines. Furthermore, bAT from tumor-bearing mice expressed higher phosphatidylcholines than that from non-tumor bearing mice, suggesting the presence of the tumor is associated with phosphatidylcholines. Conversion of phosphatidylethanolamines to phosphatidylcholines will be investigated in E0771 cells. Additional studies are projected to investigate macrophage activation by these specific classes of phospholipids. Occurrence of triglycerides and free fatty acids will be examined in bAT and similar lipidomic analyses will be carried out visceral adipose tissue, highly inflamed in obesity.

High fat diet confers vascular hyper-contractility against angiotensin II through upregulation of MLCK and CPI-17

“…Eight week-old male Sprague-Dawley rats were purchased from Koatec (Daegu, Korea) and used. They were fed with 60% Kcal fat diet (TD.06414, Harlan Teklad, Madison, WI, USA) or its control diet containing 10% Kcal fat diet (TD.94048, Harlan Teklad, Madison, WI, USA) and had free access to water for 16 weeks as others induced diet-induced obesity previously [17]. …”

EO771, is it a well‐characterized cell line for mouse mammary cancer model? Limit and uncertainty

“…The obesity of the C57BL/6 mice, induced either by taking a HFD 28,32,35,36,51,52,79 or by genetic alteration, 13,35 leads to a protumoral effect by increasing tumor growth, 13,28,32,52 promoting tumor angiogenesis, 28,32 having an immunomodulatory effect 28 as well as activating pro-tumor pathways such as AKT/mTOR. 13 Nachat-Kappes et al have used an environmental enrichment that leads to spontaneous physical activity in mice.…”

Obesity modulates the immune macroenvironment associated with breast cancer development

“…Tumor implantation was performed as previously described. Briefly, 3x10 5 tumor cells were resuspended in 1:1 PBS: Matrigel High Concentration (Corning) and subcutaneously injected in the fourth fat pad of the mammary gland [ 35 , 36 ]. Control mice were also administered with saline solution.…”